WO2003007045A1

WO2003007045A1 - Projection optical system production method

Info

Publication number: WO2003007045A1
Application number: PCT/JP2002/007017
Authority: WO
Inventors: Youhei Fujishima; Hironori Ikezawa; Toshihiko Ozawa; Yasuhiro Omura; Takeshi Suzuki
Original assignee: Nikon Corporation
Priority date: 2001-07-10
Filing date: 2002-07-10
Publication date: 2003-01-23
Also published as: JPWO2003007045A1; TW571344B

Abstract

A method for producing a projection optical system for focusing a light of a predetermined wavelength to form on a second plane a second image of a first image formed on a first plane. The optical system includes a refractive member made of at least one crystalline material of isometric system and having a transmittance to a light with a predetermined wavelength. The method comprises a designing step of acquiring predetermined design data, the designing step including a substep of determining the orientation of the crystallographic axis of a refractive member made of at least one crystalline material of isometric system while carrying out evaluation about a light having a first polarized component and a second polarized component different from the first one, a crystalline material preparing step for preparing the crystalline material, a crystal axis determining step of determining the crystal axis of the crystalline material, a refractive member forming step of forming the refractive member of predetermined shape from the crystalline material, and an assembling step of disposing the refractive member depending on the orientation of the crystallographic axis of the refractive member determined at the designing step.

Description

Itoda

Manufacturing method of projection optical system

Technical field

The present invention relates to a projection optical system, a method for manufacturing the projection optical system, and an exposure apparatus provided with the projection optical system, and is particularly used for manufacturing a micro device such as a semiconductor device or a liquid crystal display device by a photolithographic process. The present invention relates to a projection optical system suitable for an exposure apparatus to be used.

Background art

When forming micropatterns for electronic devices (microdevices) such as semiconductor integrated circuits and liquid crystal displays, the pattern of the photomask (also called a reticle) drawn by enlarging the pattern to be formed by about 4 to 5 times is projected. A method of reducing exposure transfer onto a photosensitive substrate (substrate to be exposed) such as a wafer using an exposure apparatus is used. In this type of projection exposure apparatus, the exposure wavelength keeps shifting to the shorter wavelength side in order to cope with miniaturization of semiconductor integrated circuits.

At present, the exposure wavelength of KrF excimer laser is 248 nm, but the shorter wavelength of ArF excimer laser is 193 nm. In addition, it supplies light in a wavelength band called the vacuum ultraviolet region, such as an F ₂ laser with a wavelength of 157 nm, a Kr ₂ laser with a wavelength of 14.6 nm, and a 1 " ₂ laser with a wavelength of 1 2 6 11 111. Projection exposure systems that use light sources are also being proposed, and high resolution can be achieved by increasing the numerical aperture (NA) of the projection optical system. Instead, a projection optical system having a larger numerical aperture has been developed.

Optical materials (lens materials) with good transmittance and uniformity for exposure light in the ultraviolet region having such a short wavelength are limited. In a projection optical system using an ArF excimer laser as a light source, synthetic quartz glass can be used as a lens material.However, since one type of lens material cannot sufficiently correct chromatic aberration, some Float the lens Calcium iodide crystals (fluorite) are used. On the other hand, in the projection optical science system to a light source F ₂ laser, the lens material available is limited to substantially calcium fluoride crystal (fluorite).

Disclosure of the invention

Recently, it has been reported that such birefringence exists even in cubic calcium fluoride crystals (fluorite) for ultraviolet rays having such a short wavelength. In an ultra-high-precision optical system such as a projection optical system used in the manufacture of electronic devices, the aberration caused by the birefringence of the lens material is fatal, and a lens that substantially avoids the effects of birefringence Adoption of configuration and lens design is essential.

The present invention has been made in view of the above-described problems. For example, even when a crystalline material exhibiting intrinsic birefringence such as fluorite is used, good optical performance is obtained without being substantially affected by birefringence. The purpose is to secure.

In order to achieve the above object, an invention according to claim 1 of the present invention is directed to a projection optical system that forms an image on a first surface on a second surface based on light having a predetermined wavelength. This is a method for producing a projection optical system including a refraction member made of at least one equiaxed crystal material having transparency to the light. Then, while evaluating the light of the first polarized light component and the light of the second polarized light component different from the first polarized light component, the crystal axis of the refraction member made of the at least one equiaxed crystal material is determined. A design step of obtaining predetermined design data, including an auxiliary step of determining an orientation; a crystal material preparing step of preparing the equiaxed crystal material; and a crystal for measuring a crystal axis of the equiaxed crystal material. An axis measurement step; a refraction member forming step of forming a refraction member having a predetermined shape from the equiaxed crystal material based on the design data in the design step; Assembling the refraction member based on the crystal axis orientation of the refraction member.

According to the present invention, while evaluating the influence of birefringence due to the equiaxed crystal material with respect to a plurality of polarization components, the crystal axis of the refraction member made of the equiaxed crystal material is evaluated. Since it is possible to determine the angle of incorporation so that the effect of birefringence is minimized, good optical performance can be ensured.

Furthermore, in order to achieve the above object, an invention according to claim 16 of the present invention is a projection optical system that forms an image of a first surface on a second surface based on light of a predetermined wavelength. An equiaxed refraction member made of at least one equiaxed crystal material having transparency to the light of the predetermined wavelength; and an optical performance due to intrinsic birefringence of the equiaxed refraction member. And a non-crystalline refraction member made of a non-crystalline material for compensating the deterioration.

According to the present invention, deterioration of optical performance due to intrinsic birefringence of an equiaxed refraction member made of an equiaxed crystal material can be compensated for by a non-crystal refraction member. Optical performance can be ensured.

According to another aspect of the present invention, there is provided a projection optical system that forms an image of a first surface on a second surface based on light of a predetermined wavelength, A twin refraction member made of a twin having transparency to the light.

A twin is one in which two crystals of the same phase that are in contact with each other are oriented 180 degrees around a given common low-index crystal axis, or that are in contact with each other. Two crystals are in a mirror image relationship with respect to a predetermined crystal plane. By using this twin as a crystal refraction member in the projection optical system, the effects of birefringence are opposite to each other before and after the twin plane or twin boundary. Can be reduced. This makes it possible to ensure the optical performance of the projection optical system.

It should be noted that, in the claims of the present invention, the first group of light transmitting members and the second group of light transmitting members have a positional relationship of being relatively rotated about 45 ° about the optical axis. Predetermined crystal axes (for example, crystal axes [0110], [001], [011]) oriented in a direction different from the optical axis of the first group of light transmitting members and the second group of light transmitting members. — 1] or [0 1 1]) means that the relative angle between the optical axes is about 45 °. When the crystal axis [100] is used as the optical axis, the rotational asymmetry due to the effect of birefringence about the optical axis appears at a period of 90 °, so that it is only about 45 ° about the optical axis. Having a relatively rotated positional relationship is equivalent to having a relatively rotated positional relationship of approximately 45 ° + (n X 90 °) about the optical axis (where n is an integer is there).

Further, in the claims of the present invention, it is defined that the third group of light transmitting members and the fourth group of light transmitting members have a positional relationship relatively rotated by about 60 ° about the optical axis. A predetermined crystal axis (for example, a crystal axis [—111], [111-1], or a crystal axis) oriented in a direction different from the optical axis of the third group of light transmitting members and the fourth group of light transmitting members. [1-1] means that the relative angle between the optical axes is about 60 °. When the crystal axis [1 1 1] is used as the optical axis, the rotational asymmetry due to the effect of birefringence around the optical axis appears at a period of 120 °, so it is almost 60 ° around the optical axis. Having a positional relationship rotated relative to the optical axis is equivalent to having a positional relationship rotated relative to the optical axis by about 60 ° + (n X l 20 °) (where n is an integer). Is).

Further, in the claims of the present invention, the fifth group of light transmitting members and the sixth group of light transmitting members have a positional relationship relatively rotated by about 90 ° about the optical axis. Predetermined crystal axes (eg, crystal axes [00 1], [-111], [-1]) oriented in directions different from the optical axes of the fifth group of light transmitting members and the sixth group of light transmitting members. 1 0], or

[1-1 1]) means that the relative angle between the optical axes is about 90 °. When the crystal axis [1 110] is used as the optical axis, the rotational asymmetry of the effect of birefringence around the optical axis appears at a period of 180 °, so that it is almost Having a positional relationship relatively rotated by 90 ° has the same meaning as having a positional relationship rotated relatively by approximately 90 ° + (n X 180 °) about the optical axis ( n is an integer). BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a flowchart schematically showing a method for manufacturing a projection optical system according to a first embodiment of the present invention.

FIG. 2 is a flowchart schematically showing the design process S1 in the first embodiment of the present invention.

FIG. 3 is a diagram showing an example of evaluation points of the optical performance of the projection optical system according to the first embodiment of the present invention.

FIG. 4 is a flow chart for explaining details of step S12 in the first embodiment of the present invention. FIG. 5 is a view for explaining the crystal axis orientation of the equiaxed crystal material in the first embodiment of the present invention.

FIG. 6 is a flowchart showing details of the crystal material preparing step S2 in the first embodiment of the present invention.

FIG. 7 is a diagram schematically showing a ray camera.

FIG. 8 is a diagram showing a schematic configuration of a birefringence measuring instrument.

FIG. 9 is a diagram showing a schematic configuration of an interferometer apparatus for measuring an error of a lens surface shape.

FIG. 10 is a flowchart showing an outline of a method for manufacturing a projection optical system according to the second embodiment of the present invention.

FIG. 11A, FIG. 11B, and FIG. 11C are diagrams illustrating an example of a method of reducing intrinsic birefringence by combining a plurality of equiaxed crystal materials.

FIG. 12 is a diagram schematically showing an interferometer device for measuring the absolute value of the refractive index and the refractive index distribution.

FIG. 13 is a flowchart showing details of the assembling step S5 of the method for manufacturing a projection optical system according to the second embodiment of the present invention.

FIG. 14 is a diagram schematically showing an aberration measuring apparatus using the principle of the phase retrieval method. FIG. 15 is a diagram schematically showing an external adjustment mechanism of the projection optical system according to the second embodiment of the present invention.

FIG. 16A, FIG. 16B, and FIG. 16C are views for explaining an optical member having an aspheric surface and an optical member having a changed Z or birefringence distribution.

FIG. 17 is a view schematically showing an exposure apparatus including a projection optical system manufactured according to the first embodiment or the second embodiment.

FIGS. 18A, 18B, and 18C schematically show the projection optical system of the fourth embodiment as an example of a method of reducing the intrinsic birefringence by combining a plurality of equiaxed crystal materials. FIG. 5 is a diagram schematically showing a crystal direction of members 5 la and 51 b.

FIG. 19 is a diagram schematically showing a projection optical system according to a fifth embodiment as an example of a technique for reducing intrinsic birefringence by combining a plurality of equiaxed crystal materials.

FIG. 20 is a diagram schematically showing a projection optical system according to an eighth embodiment as an example of a method of reducing intrinsic birefringence by combining a plurality of equiaxed crystal materials.

FIG. 21 is a diagram showing a lens configuration of a projection optical system according to a first embodiment as a numerical embodiment according to the present invention.

FIGS. 22A, 22B and 22C show the point image intensity distribution of the projection optical system in the first embodiment.

FIGS. 23A and 23B show the point image intensity distribution of the projection optical system in the first embodiment. FIG. 24 is a diagram showing a lens configuration of a projection optical system according to a second embodiment as a numerical embodiment according to the present invention.

FIGS. 25A, 25B, 25C, and 25D show the point image intensity distribution of the projection optical system in the second example.

FIGS. 26A and 26B show the point image intensity distribution of the projection optical system in the second embodiment. Figure 27 is a flowchart of the method for obtaining a semiconductor device as a microdevice.

Figure 28 is a flowchart of the method used to obtain a liquid crystal display element as a microdevice. It is.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a method for manufacturing a projection optical system according to the first embodiment of the present invention will be described with reference to the drawings. Before describing the details of the method of manufacturing the projection optical system according to the present embodiment, an outline thereof will be briefly described with reference to FIG. 1 to facilitate understanding. FIG. 1 is a flowchart schematically illustrating a method for manufacturing a projection optical system according to a first embodiment of the present invention.

As shown in FIG. 1, the method for manufacturing a projection optical system according to the present embodiment includes a design step S1, a crystal material preparation step S2, a crystal axis measurement step S3, a refraction member forming step S4, and an assembly step S1. With 5.

In the design process S1, when designing the projection optical system using the ray tracing software, the ray tracing of the projection optical system is performed using the rays of the plural polarization components, and the ray tracing is performed under each polarization component. The aberration, preferably the wavefront aberration for each polarization component is calculated. Then, while evaluating the projection optical system with respect to the aberration for each polarization component and the scalar difference which is a scalar component of the combination of the polarization component aberrations, a plurality of optical members (refractive members, By optimizing the parameters of the reflection member, diffraction member, etc., the design data consisting of these parameters is obtained. As this parameter, in addition to the conventional parameters such as the surface shape of the optical member, the spacing between the optical members, the refractive index of the optical member, and the like, when the optical member is a crystalline material, the crystal axis orientation is used as the parameter. .

In the crystal material preparation step S2, an equiaxed crystal system having a light transmission property with respect to the wavelength used by the projection optical system (the unit length of the crystal axes is equal to each other, and each crystal axis at the intersection of each crystal axis is used) Prepare a crystalline material whose crystallographic angle is 90 °. In the crystal axis measurement step S3, the crystal axis of the crystal material prepared in the crystal material preparation step is measured. At this time, for example, a method of directly measuring the crystal axis direction by performing Laue measurement, or measuring the birefringence of the crystal material, and measuring based on the relationship between the known crystal axis direction and the amount of birefringence. Method to determine the crystal axis orientation from the determined birefringence. Can be.

In the bending member forming step S4, processing (polishing) of the crystal material prepared in the crystal preparation step is performed so that the bending member has the parameters (design data) obtained in the designing step. In the present embodiment, the order of the crystal axis measurement step S3 and the refraction member forming step S4 may be any order. For example, when the refraction member formation step S4 is performed first, the shape of the refraction member It is only necessary to measure the crystal axis of the crystal material that has been processed in advance, and if the crystal axis measurement step S3 is performed first, the refraction member or the relevant What is necessary is just to give the information of the crystal axis direction to the holding member holding the refraction member.

In the assembling step S5, the processed refraction member is incorporated in the lens barrel of the projection optical system according to the design data obtained in the design step. At this time, the crystal axis of the refraction member made of an equiaxed crystal material is positioned so as to be the crystal axis orientation in the design data obtained in the design process.

The outline of the method of manufacturing a projection optical system according to an embodiment of the present invention has been described above. Next, the detailed procedure will be described with reference to FIGS.

FIG. 2 is a flowchart schematically showing the design process S1. As shown in FIG. 2, in a design process S1, a step S11 of inputting initial values of design parameters, based on the design parameters, evaluates the optical performance of the projection optical system under a plurality of polarization components. Step S12, step S13 for judging whether the optical performance calculated in step S12 is within a predetermined standard, and design parameters in step S13 if the optical performance is not in a predetermined standard. Step S14 for changing is provided.

In this embodiment, the design parameters include the surface shape, the surface interval, the amount of eccentricity, the inclination with respect to the optical axis, and the azimuth centered on the optical axis of the optical members (lens, reflecting surface, etc.) constituting the projection optical system , Refractive index, birefringence distribution, reflectance, transmittance, transmittance distribution, effective diameter, tolerance, etc., the structure of the thin film formed on the surface of these optical members, that is, the number of thin films, the thickness of each layer , Material of each layer (if necessary, absorption coefficient of each layer), etc. Can be.

Next, with reference to FIGS. 3 and 4, details of step S12 for evaluating the optical performance of the projection optical system under a plurality of polarization components will be described. Here, FIG. 3 is a diagram showing an example of evaluation points of the optical performance of the projection optical system, and FIG. 4 is a flowchart for explaining details of step S12.

As shown in FIG. 3, in the present embodiment, the evaluation point W0 on the optical axis Ax of the image plane W as the second plane of the projection optical system PL, the arbitrary image height on the image plane W (for example, the outermost image height) The evaluation point W i) is used as the evaluation point. Note that the number of evaluation points W i of arbitrary image heights on the image plane W is not limited to one, and a plurality of evaluation points of arbitrary image heights may be used. The imaging light beam incident on the evaluation point W0 corresponds to the light beam from the point R0 on the optical axis Ax on the object plane R as the first surface of the projection optical system, and is incident on the evaluation point Wi. The formed image light beam corresponds to a light beam from a point Ri at an arbitrary object height on the object plane R.

Further, the plurality of polarization components in step S12 include, for example, an X polarization component that vibrates in a predetermined X direction in a plane normal to the optical axis of the projection optical system, and a direction orthogonal to the X direction in the plane. Γ-polarized light component that vibrates in the γ-direction can be used. Further, the plurality of polarization components have an R polarization component that vibrates in a direction including the optical axis (radiation direction R) in a plane normal to the optical axis, and a vibration direction orthogonal to the R polarization component. A zero polarization component (a polarization component having a vibration direction in the tangential direction Θ) and may be used, and both the XY polarization component and the RΘ polarization component (that is, four polarization components) may be used.

In this embodiment, a phase distribution WO (ρ, Θ) (W i (, θ)) at the exit pupil PS of the projection optical system PL is obtained for each of a plurality of polarization components. On the exit pupil PS in polar coordinates (ρ, Θ). Here, ρ is a normalized pupil radius obtained by normalizing the radius of the exit pupil plane P S to 1, and 0 is the center of the exit pupil plane P S, typically, the radial angle in polar coordinates with the optical axis as the origin.

(Step S 1 2 1) In step S 1 21, the projection optical system Ρ L design parameters are input. If this step S121 is executed immediately after step S11 in FIG. 2, this design parameter becomes the initial value of the design parameter input in step S11. If it is executed after step S14 in step 2, the design parameters will be those changed in step S14.

Note that the above design parameters are used to calculate the complex amplitude of each ray entered from the object side (reticle plane R side) of the projection optical system PL and tracing the ray on the object plane (wafer plane W). It is necessary information.

(Step S122) Next, the computer performs ray tracing, and the first polarization direction of the imaging light flux incident on an arbitrary evaluation target image point Xi (for example, the highest peripheral image height) as shown in FIG. The phase distribution WH i (, 0) and the second polarization direction phase distribution WV i (ρ, Θ), and the first polarization direction phase distribution WH 0 (p , Θ) and the second polarization direction phase distribution WVO (ρ, Θ) are calculated.

Note that the “first polarization direction” and the “second polarization direction” here are two polarization directions orthogonal to each other on the exit pupil plane PS. For example, the XY polarization direction, the polarization direction, or XY and R directions双方 Both polarization directions can be applied.

In the present embodiment, the complex amplitudes to be calculated when calculating these phase distributions are not only for the end of the exit pupil plane PS of the projection optical system PL but also for the entire area of the exit pupil plane PS. As shown in Fig. 7, the ray tracing of the imaging light beam incident on the evaluation target image point Xi is performed by changing the exit pupil of the light beam Lfi emitted from the conjugate point Ri on Xi at different exit angles. This is performed for each ray that passes through different positions on the surface PS (the maximum exit angle of the ray to be traced depends on the image-side numerical aperture of the projection optical system PL).

In this embodiment, ray tracing is performed on an optical member made of an equiaxed crystal material having intrinsic birefringence, but the distribution of birefringence with respect to the crystal axis in such an optical member is described below. , 157ηια litho opened on May 15, 2001 At the 2nd International Symposium on 157nm Lithography

Standards and Technology) published by John H. Burnett et al.

Then, by such ray tracing, the exit pupil plane P of the projection optical system P L of the light beam L f i

The complex amplitude distribution of the first polarization direction and the complex amplitude distribution of the second polarization direction in S are obtained, and the first polarization direction phase distribution and the second side polarization direction phase distribution are obtained from these distributions, respectively. The distribution represented by the polar coordinates (p, Θ) on the exit pupil plane PS is represented by the first polarization direction phase distribution WH i (p, 0) of the imaging light flux incident on the evaluation target image point X i, respectively.位相 Phase distribution in the second polarization direction WV i (ρ, Θ). In addition,

_Ρ is a normalized pupil radius obtained by standardizing the radius of the exit pupil plane PS to 1, and Θ is a radial angle in polar coordinates with the origin at the center of the exit pupil plane PS.

Similarly, the ray tracing of the imaging light beam incident on the central image height Χ0 is also performed by the conjugate point of χο

This is performed for each light ray of the light beam Lf0 emitted from R0, which is emitted at different emission angles and passes through different positions on the exit pupil plane PS. Then, a complex amplitude distribution in the first polarization direction and a complex amplitude distribution in the second direction of the light flux L fi are obtained, and these distributions are represented by polar coordinates ( _Ρ , Θ) on the exit pupil plane PS. And the first direction phase distribution WHO (p, 0) of the imaging light flux incident on the

The two-way phase distribution is WV0 (ρ, Θ).

(Step S 1 2 3) Next, the computer calculates the average phase distribution WA i (ρ, θ) of the evaluation target image point X i and the average phase distribution WA 0 (ρ, Θ) of the central image height X 0. Is calculated by the following equations (1) and (2).

(1) WA i (ρ, θ) = (WV i (p, Θ) + WH i, Θ)) / 2

(2) WAO (p, Θ) = (WV 0 (p, Θ) + WH0 (p, Θ)) / 2 That is, the average phase distribution WA i (p, Θ) is equal to WV i (p, Θ). WVO (p,

This is the distribution of intermediate values obtained by matching the coordinates with Θ). Then, the RMS values wai and waO of the obtained average phase distributions WA i (p, Θ) and WA0 (ρ, θ) are obtained. These RMS values correspond to the wavefront difference of the projection optical system PL.

(Step S124) The computer refers to WVip, Θ), WHi (ρ, Θ), WVO (ρ, θ), WHO (ρ, θ) obtained in step S122. The retardation distribution δ W i (ρ, Θ) of the image point X i to be evaluated and the retardation distribution δ WO (p, θ) of the evaluation image point Χ 光 on the optical axis are expressed by the following equation (3) ) And (4).

(3) δ W i (, θ) = WV i (ρ, θ) -WH ί (ρ, θ)

(4) δ WO (ρ, θ) = WVO (ρ, θ) -WHO (ρ, θ)

That is, the retardation distribution SW i (ρ, θ) is a distribution of differences obtained by matching the coordinates of WVi (p, Θ) and WVi (p, Θ), and the retardation distribution SWO (ρ, Θ) is the distribution of differences obtained by matching the coordinates of WVO, Θ) and WVO (ρ, Θ).

Further, the RMS values S w i and S wO of the obtained retardation distributions δ W i (ρ, θ) and β WO (ρ, θ) are obtained.

In general, when the retardation is large, the contrast of the pattern image decreases.Therefore, the RMS value of the retardation distribution δW i (ρ, θ) and the RMS value of the retardation distribution SWO (p, 0) are evaluated. It shows the contrast of the image at the target image point and the poor contrast of the image at the evaluation image point on the optical axis.

(Step S125) The computer refers to the retardation distribution SWO obtained in step S124, calculates its RMS value Sw0, and its average value A [δWO] in the exit pupil plane, and The PSF value is obtained by the equation (5).

ヽ₁ 4JT ² X SwO ² + 2π ² x A [dW0f

(5) PSF = 1 ―

2 This PSF value is approximately the maximum value of the point spread distribution caused by retardation. Corresponding to the value of The smaller the PSF value, the more the point image intensity distribution is degraded.

In the present embodiment, in addition to each of w ai and w a0 obtained above, evaluation indices such as the following (a), (b), (c), and (d) may be obtained.

(a) The RMS value of each term obtained by subjecting WA i (p, 0) to Zernike expansion, or the RMS value of each term obtained by grouping Z and a plurality of terms obtained by subjecting it to a Zuelke expansion.

(b) The RMS value of each term obtained by subjecting WA O (ρ, Θ) to Zernike expansion, and / or the RMS value of each term obtained by grouping a plurality of terms obtained by subjecting the Zernike expansion to WAO (ρ, Θ).

(c) The average phase distribution ΔWA i (ρ, 0) or Z of the evaluation target image point X i based on the evaluation image point X 0 on the optical axis and the RMS value of the average phase distribution S WA i.

(d) RMS value of each term obtained by Zernike expansion of AWA i (p, Θ), or RMS value of each term obtained by grouping a plurality of terms obtained by Z and Zerke expansion.

Based on the optical performance calculated in step S12 (for example, average phase distribution, retardation distribution, their RMS value, PSF value, etc.), in step S13, the calculated optical performance is set to a predetermined value. Judge whether it is within the standard. Here, if it is within the standard, the design data (design parameter) is output, and the design process S 1 is completed. If the calculated optical manufacturing is not within the predetermined standard, the process proceeds to step S14.

In step S14, at least a part of the design parameters of the projection optical system is changed, and the process proceeds to step S12. In this embodiment, this loop is repeated until the calculated optical performance falls within a predetermined standard.

When changing design parameters, first of all, the surface shape, spacing, eccentricity, inclination with respect to the optical axis, and refraction of the optical members (lenses, reflection surfaces, etc.) that constitute the projection optical system Only the parameters of the optical system made of an amorphous material, such as the ratio, effective diameter, and tolerance, are changed to correct the scalar component aberration in the optical performance of the projection optical system, and then the thin film structure and optical members The parameters such as the birefringence distribution and the azimuth around the optical axis may be changed to correct the aberration of one scalar component and polarization component.

For example, considering the case where fluorite (calcium fluoride, CaF ₂ ) is used as an equiaxed crystal material, this fluorite has a crystal axis [111] or the crystal axis [111]. Conventionally, a refraction member having a crystal axis equivalent to that of the optical axis is formed, so that the accumulation of know-how in forming the refraction member compared to the case of using another crystal axis as the optical axis is known. The product is large. Therefore, as shown in Fig. 5, for example, when designing the projection optical system, the optical member made of fluorite in the projection optical system is designed in such a manner that the optical axis coincides with the crystal axis [111]. and, as a design parameter of the optical member formed of the fluorite, adopting the azimuth angle theta _Z around the optical axis can be considered as an example.

As described above, in the design process S1, the design data of the projection optical system having the optical performance within the predetermined standard in calculation (design parameters: the surface of the optical member (lens, reflecting surface, etc.) constituting the projection optical system) Shape, spacing, eccentricity, inclination to the optical axis, azimuth around the optical axis, refractive index, birefringence distribution, reflectance, transmittance, transmittance distribution, effective diameter, tolerance, etc. It is possible to obtain the structure of the thin film formed on the surface of the optical member, that is, the number of thin films, the thickness of each layer, and the material of each layer (absorption coefficient of each layer if necessary).

Next, the crystal material preparing step S2 will be described with reference to the flowchart in FIG. FIG. 6 is a flowchart showing the details of the crystal material preparing step S2 for preparing an equiaxed crystal material having optical transparency with respect to the wavelength used by the projection optical system. In addition, as such an equiaxed crystal material, fluorite (calcium fluoride, CaF ₂ ) and barium fluoride (BaF ₂ ) are exemplified.

In the following description, a case where fluorite is applied as an equiaxed crystal material will be described as an example. (Step S21) In step S21, a pretreatment for causing a deoxygenation reaction of the powder raw material is performed. When fluorite single crystals used in the ultraviolet region or vacuum ultraviolet region are grown by the Bridgeman method, it is common to use high-purity raw materials of artificial synthesis. Furthermore, when only the raw material is melted and crystallized, it tends to become cloudy and devitrified. Therefore, measures have been taken to prevent cloudiness by adding a heating force and heating. Typical scavengers for use in the pretreatment or growth of fluorite single crystal, and lead fluoride (P b F ₂₎ is. In addition, an additive substance that chemically reacts with impurities contained in the raw material and acts to remove it is generally called a steam venter. In the pretreatment in this example, first, a scavenger is added to a high-purity powder raw material and mixed well. Then, the deoxygenation reaction is advanced by heating to a temperature above the melting point of the scavenger and below the melting point of fluorite.

Thereafter, the temperature may be lowered to room temperature to form a sintered body, or the temperature may be further raised to once melt the raw material, and then lowered to room temperature to obtain a polycrystalline body. The sintered body or polycrystalline body deoxygenated as described above is referred to as a pre-treated product.

(Step S22) Next, in step S22, a single crystal ingot is obtained by further growing a crystal using this pre-processed product.

It is widely known that crystal growth methods can be broadly classified into solidification of a melt, precipitation from a solution, deposition from a gas, and growth of solid particles. Let it grow.

First, the preprocessed product is stored in a container and placed at a predetermined position in a vertical Bridgman apparatus (crystal growth furnace). Then, the pre-processed product stored in the container is heated and melted. After reaching the melting point of the pretreated product, crystallization is started after a predetermined time has elapsed. When all of the melt crystallizes, slowly cool to room temperature and remove it as an ingot.

(Step S23) In step S23, the ingot is cut to obtain a disk material having the same size and shape as the optical member to be obtained in a bending member forming step S4 described later. Here, the optical member to be obtained in the refractive member forming step S4 is a lens. In such a case, it is preferable that the shape of the disk material be a thin cylindrical shape. The diameter and thickness of the cylindrical disk material are determined according to the effective diameter (outer diameter) of the lens and the thickness in the optical axis direction. It is desirable that

(Step S24) In step S24, an annealing process is performed on the disk material cut out from the fluorite single crystal ingot. By performing these steps S21 to S24, a crystal material composed of a fluorite single crystal is obtained.

Next, the crystal axis measuring step S3 will be described. In the crystal axis measurement step S3, the crystal axis of the crystal material prepared in the crystal material preparation step S2 is measured. At this time, a first measurement technique for directly measuring the orientation of the crystal axis and a second measurement technique for indirectly determining the crystal axis orientation by measuring the birefringence of the crystal material can be considered. First, a first measurement technique for directly measuring the orientation of the crystal axis will be described.

The first measurement technique uses the technique of X-ray crystallography to directly measure the crystal structure of a crystalline material and, consequently, the crystal axis. As such a measuring method, for example, the Laue method is known. Hereinafter, the case where the Laue method is applied as the first measurement technique will be briefly described with reference to FIG. FIG. 7 is a diagram schematically showing a Laue camera.

As shown in FIG. 7, the Laue force melody for realizing the crystal axis measurement by the Laue method is composed of an X-ray source 100 and an X-ray 101 from the X-ray source 100 as a crystal material as a sample. A collimator 102 for guiding to 103 is provided, and a photosensitive member 105 exposed to X-ray diffraction 104 diffracted from the crystal material 103. Here, although not shown in FIG. 7, a pair of opposing slits are provided inside the collimator 102 penetrating the X-ray photosensitive member 105.

In the first measurement method, first, the crystal material 103 prepared in the crystal material preparation step S2 is irradiated with X-rays 101, and the crystal material 103 is subjected to diffraction X-rays 104. Generates. Then, the X-ray photosensitive member 105 such as an X-ray film or an imaging plate disposed on the X-ray incident side of the crystal material 103 is exposed by the diffracted X-ray 104, A visible image (diffraction image) of a pattern corresponding to the crystal structure is formed on the X-ray photosensitive member 105. This diffraction image (Rae pattern) is spot-like when the crystalline material is a single crystal, and these spots are called Ray-points. The crystal material used in the present embodiment is fluorite, and its crystal structure is known. Therefore, by analyzing the Laue spots, the crystal orientation of the crystal can be determined.

Note that the first measurement method for directly measuring the crystal axis is not limited to the Laue method, but may be a rotation method or a vibration method of irradiating an X-ray while rotating or vibrating a crystal, a Weissenberg method, a precession method, or the like. Other X-ray crystallography techniques, methods using the cleavage properties of crystalline materials, Observation of compression images (or impressions) with specific shapes that appear on the surface of crystalline materials by giving plastic deformation of the crystalline materials A mechanical method such as a method may be used.

Next, a brief description will be given of a second measurement method for indirectly determining the crystal axis orientation by measuring the birefringence of a crystal material. In the second measurement method, first, the crystal axis direction of the crystal material is associated with the amount of birefringence in that direction. At this time, the crystal axis orientation of the sample of the crystal material is measured using the first measurement method described above. Then, the birefringence is measured for each of a plurality of crystal axes of the crystal material sample.

FIG. 8 is a diagram showing a schematic configuration of a birefringence measuring instrument. In FIG. 8, light from a light source 110 is converted by a polarizer 111 into linearly polarized light having a vibrating plane inclined by π / 4 from the horizontal direction (X direction). Then, the linearly polarized light is subjected to phase modulation by the photoelastic modulator 112, and is applied to the crystal material sample 113. In other words, the linearly polarized light of which phase changes is incident on the crystalline material sample 113. The light transmitted through the crystal material sample 113 is guided to the analyzer 114, and only polarized light having a vibration plane in the horizontal direction (X direction) passes through the analyzer 114 and the photodetector 111 Is detected by By measuring how much light is detected by the photodetector 115 at a predetermined phase delay generated by the photoelastic modulator 112, the phase delay is measured by changing the amount of phase delay. The direction of the axis and its refractive index, and the refractive index in the fast axis can be determined. it can.

When birefringence is present in a sample, the phase of two linearly polarized lights whose vibration planes (polarization planes) passing through the sample are orthogonal to each other changes due to a difference in the refractive index. In other words, the phase of one polarized light leads or lags the other, but the polarization direction in which the phase advances is called the fast axis, and the polarization direction in which the phase lags is called the slow axis. . In this example, birefringence measurement was performed for each crystal axis of a crystal material sample whose crystal axis direction was known by the first measurement method, and the crystal axis direction of the crystal material and the amount of birefringence in that direction were measured. Is associated with. At this time, in addition to typical crystal axes of [100], [1 10] and “1 1 1” as crystal axes of the crystal material to be measured, [1 1 2], [2 1 0] and [2 1 1] ], Etc. (Note that the crystal axes [010], [0

01] is a crystal axis equivalent to the crystal axis [100], and the crystal axes [01 1] and [10 1] are crystal axes equivalent to the crystal axis [1 10]. In addition, the intermediate crystal axis between the measured crystal axes may be interpolated using a predetermined interpolation operation expression.

In the crystal axis measurement step S3 to which the second method is applied, the birefringence of the crystal material prepared in the crystal material preparation step S2 is measured using the birefringence measurement device shown in FIG. Then, since the correspondence between the crystal axis orientation and the birefringence is determined in advance, the crystal axis orientation is calculated from the measured birefringence using this correspondence.

Thus, according to the second technique, the crystal axis orientation of the crystal material can be obtained without directly measuring the crystal axis orientation.

Next, the bending member forming step S4 will be described. In the refraction member forming step S4, the crystal material prepared in the crystal material preparation step S2 is processed to form an optical member (a lens or the like) having a predetermined shape. At this time, the order of the crystal axis measurement step S3 and the refraction member formation step S4 may be any order, for example, a first member formation method of performing the refraction member formation step S4 after the crystal axis measurement step S3, A second member forming method of performing a crystal axis measurement step after the refraction member forming step S4, and a third member forming method of simultaneously performing the crystal axis measurement step S3 and the crystal axis measurement step S4 can be considered. First, the first member forming method will be described. In the first member formation method, the disk material prepared in the crystal material preparation step S2 is ground so that the optical member becomes the design data including the parameters related to the crystal axis orientation obtained in the design step S1. Processing such as polishing. At this time, a predetermined mark or the like is provided on the processed optical member so that the crystal axis direction of the optical member can be recognized.

Specifically, the refraction forming the projection optical system is performed using a material that is ground as necessary from a crystal material (typically a disk material) whose crystal axis orientation has been measured in the crystal material preparation step S2. Manufacture components. That is, the surface of each lens is polished in accordance with a well-known polishing process with the target of the surface shape and the surface interval in the design data, and a refraction member having a lens surface of a predetermined shape is manufactured. At this time, polishing is repeated while measuring the error in the surface shape of each lens with an interferometer, and the surface shape of each lens is brought close to the target surface shape (best fit spherical shape). Thus, when the surface shape error of each lens falls within a predetermined range, the error of the surface shape of each lens is measured using, for example, a precise interferometer device shown in FIG.

The interferometer device shown in FIG. 9 is suitable for measuring the surface shape of a spherical lens having a spherical design value. In FIG. 9, light emitted from the interferometer unit 122 controlled by the control system 122 enters the Fizeau lens 123 supported on the Fizeau stage 123a. Here, the light reflected by the reference surface (Fizeau surface) of the Fizeau lens 1 23 becomes the reference light, and returns to the interferometer unit 1 22. Although FIG. 9 shows the Fizeau lens 123 with a single lens, an actual Fizeau lens is composed of a plurality of lenses (lens groups). On the other hand, the light transmitted through the Fizeau lens 123 becomes measurement light, and is incident on the optical surface of the lens 124 to be measured.

The measurement light reflected by the test optical surface of the test lens 1 2 4 returns to the interferometer unit 1 2 2 via the Fizeau lens 1 2 3. In this way, based on the phase shift between the reference light and the measurement light returned to the interferometer unit 122, the wavefront aberration of the test optical surface of the test lens 124 with respect to the reference surface and, consequently, the test lens 1 2 4 Error in surface shape (design The deviation from the best fit spherical surface is measured. For details of the measurement of the surface shape error of the spherical lens by the interferometer, refer to, for example, Japanese Patent Application Laid-Open Nos. 7-123535, 7-113609, and 10-154657. Can be. When the surface shape error of the aspherical lens is measured using an interferometer, a reference member having a planar reference surface in place of the Fizeau lens 113 in the interferometer device of FIG. An aspherical wave forming member for converting light transmitted through the reference member into an aspherical wave having a predetermined shape is provided on the Fizeau stage 113a. Here, the aspherical wave forming member is configured by a lens, a zone plate, or a combination thereof, and converts the plane wave from the reference member into an aspherical wave corresponding to the surface shape of the optical surface to be measured, which is a measurement target. It is something to convert. Regarding such a method of measuring an aspherical lens, for example, JP-A-10-260020, JP-A-10-260024, and JP-A-11-11784 can be referred to.

In the first member forming method in the bending member forming step S4, measurement and polishing are repeated until the measured surface shape falls within a predetermined range.

In recent years, in order to minimize the stress applied to a lens when holding an optical member such as a lens, a plurality of ridges (ridges) are provided on the periphery of the lens to hold the lens. It has been proposed that a plurality of ridges be kinematically held by a member (lens sensor) (see Japanese Patent Application Laid-Open No. 2001-74991). Here, the crystal axis orientation of the processed optical member can also be indicated by processing such a plurality of raised portions to have the crystal axis orientation of the optical member. Further, according to the above-described optical member holding method, since the relationship between the holding member and the position / posture of the optical member is constant, information (a mark or the like) indicating the crystal axis direction of the optical member is provided on this holding member. May be provided.

Next, a second member forming method will be described. In the second member forming method, the disc material prepared in the crystal material preparing step S2 is subjected to processing such as polishing and polishing. At this time, of the design data obtained in the design process S1, the surface shape, Processing is performed using parameters such as (outer diameter) (without using parameters related to crystal axis orientation). Note that, in the second member forming method as well, the measurement and polishing are repeated until the surface shape falls within a predetermined range, as in the first member forming method. Then, the crystal axis direction of the processed optical member is measured using the above-described first measurement method, and information on the measured crystal axis direction is provided on the optical member processed with, for example, a mark. As described above, in the present embodiment, the crystal axis orientation can be determined even after being processed into a lens or the like.

In the second member forming method, the crystal axis direction was measured after forming the refraction member from the crystalline material. However, the measurement of the crystal axis direction may be performed during the formation of the refraction member. Good (3rd member formation method).

Then, in the assembling step S5, the space in the optical axis direction, the position in the vertical direction of the optical axis, and the rotation angle (azimuth angle) around the optical axis of each processed optical member were obtained in the design step S1. Position each optical member so as to meet the design parameters, and assemble the projection optical system.

As described above, according to the method for manufacturing a projection optical system according to the first embodiment, the influence of birefringence caused by an equiaxed crystal material such as fluorite or barium fluoride is affected for a plurality of polarization components. While evaluating, it is possible to determine the angle of incorporation of the crystal axis of the refraction member made of this equiaxed crystal material so that the influence of birefringence is minimized, so that good optical performance ^ is obtained. Can be secured.

In the first embodiment described above, by optimizing the crystal axis orientation of the refraction member made of an equiaxed crystal material, the force S for reducing the aberration of the projection optical system, and optimizing the crystal axis orientation only, The required optical performance may not be satisfied. Next, as a second embodiment, a method of manufacturing a projection optical system for compensating for the deterioration of optical properties due to intrinsic birefringence of an equiaxed refraction member made of an equiaxed crystal material by using an amorphous refraction member Is explained. Before describing the details of the method of manufacturing the projection optical system according to the present embodiment, an outline thereof will be briefly described with reference to FIG. 10 to facilitate understanding. Figure 10 shows the book 6 is a flowchart schematically illustrating a method of manufacturing a projection optical system according to a second embodiment of the present invention.

As shown in FIG. 10, the method of manufacturing the projection optical system of the second embodiment includes a design process S1, a crystal material preparation process S2, a crystal axis measurement process S3, which the manufacturing method of the first embodiment has. In addition to the first refraction member forming step S4 and the assembling step S5, the method includes an amorphous material preparing step S6, a birefringence amount measuring step S7, and a second refraction member forming step S8. Note that the first bending member forming step S4 is the same process as the bending member forming step S4 of the first embodiment. In the present embodiment, the bending is performed to avoid confusion with the second bending member forming step S8. It is referred to as a first bending member forming step S4 instead of the member forming step S4.

Hereinafter, differences from the manufacturing method according to the first embodiment will be described.

First, in the design step S1, as the parameters of the projection optical system to be optimized, in addition to the design parameters in the first embodiment, for example, the birefringence of an amorphous material such as quartz doped with quartz and fluorine is used. Used.

For example, as shown in FIG. 11A, a projection optical system includes a plurality of refraction members 11 and 12 made of an equiaxed crystal material and an amorphous material such as quartz or fluorine-doped quartz. An optical system including a refraction member 13 made of

Here, in the first refraction member 11 and the second refraction member 12 made of an equiaxed crystal material, for example, fluorite, the crystal axis [1 1 1] is made to coincide with the optical axis Ax. It is arranged, and the second refraction member 12 is rotated 60 ° about the optical axis Ax in the XY plane with respect to the first refraction member 11. At this time, the effect of birefringence by the first refraction member 11 is shown in (b) of FIG. 11B, and the effect of birefringence by the second refraction member 12 is shown in (a) of FIG. 11B. Show.

(A) to (c) in Fig. 11B and Fig. 11C show the distribution of the birefringence index with respect to the incident angle of the light beam, and six concentric circles indicated by broken lines in the figure indicate one scale of 10 °. Represents. Accordingly, the innermost circle represents a region having an incident angle of 10 ° with respect to the optical axis, and the outermost circle represents a region having an incident angle of 60 ° with respect to the optical axis. A black circle indicates a region having a relatively large refractive index and no birefringence, and a white circle indicates a region having a relatively small refractive index and no birefringence. On the other hand, the thick circle and the thick double arrow indicate the direction of the relatively large refractive index (the direction of the slow axis) in the birefringent area, and the thin circle and the thin double arrow indicate the relatively small refractive index in the birefringent area. Represents the direction (fast axis).

As shown in (b) of FIG. 11B and (c) of FIG. 11B, in the first and second refraction members 11 and 12, the crystal axis [1] The region corresponding to [1 1] is a region having a relatively small refractive index and no birefringence. The regions corresponding to the crystal axes [100], [010], and [001] are regions having a relatively large refractive index and no birefringence. Further, the regions corresponding to the crystal axes [1 1 0], [1 0 1], and [0 1 1] have a relatively small refractive index for circumferentially polarized light and a relatively large refractive index for radially polarized light. It becomes a refraction area. Thus, in each of the refraction members 11 and 12, in the region of 35.26 ° (the angle between the crystal axis [1 1 1] and the crystal axis [1 1 0]) from the optical axis Ax, It can be seen that the influence of birefringence is greatest.

(C) of FIG. 11B combines the effects of birefringence by the first and second refraction members 11 and 12 exhibiting a relative rotation angle of 60 ° about the optical axis. As is clear from (c) of FIG. 11B, in the first and second refraction members 11 and 12 as a whole, the crystal axes [1 110], [101], [100] where the birefringence is the maximum 0 1 1] is reduced. However, in the region at 3.5.26 ° from the optical axis, that is, the region relatively close to the optical axis, there remains a birefringent region in which the refractive index for circumferentially polarized light is smaller than that for radially polarized light. . In other words, in the method of adjusting the angle of the crystal axis of the refraction member made of an equiaxed crystal material, the effect of birefringence may be affected to some extent depending on the angle of the crystal axis, and a sufficiently good imaging performance ( Optical performance) may be difficult.

Therefore, in this embodiment, the birefringence of the refraction members 11 and 12 is applied to the refraction members 13 and 11 made of an amorphous material different from the refraction members 11 and 12 made of an equiaxed crystal material. > Give birefringence distribution. FIG. 11E shows the birefringence distribution of the refraction member 13. A method of giving a desired birefringence distribution to a refraction member made of an amorphous material will be described in a non-crystalline material preparation step S6 described later.

In the design step S1, the birefringence distribution of the refraction member made of such an amorphous material is calculated. Specifically, the parameters of the birefringence distribution of the refraction member are added to the design parameters (design data) in the design process S1 of the first embodiment, and the steps S11 to S11 are performed as in the first embodiment. Perform 1 to 4.

In the present embodiment, parameters other than the parameters of the birefringence distribution of the refraction member made of an amorphous material (the same parameters as the parameters of the first embodiment) are optimized, and the parameters are calculated based on the optimized parameters. It is also possible to use a method of correcting the residual amount of aberration by optimizing the parameters of the birefringence distribution of the refractive member made of an amorphous material.

Similarly to the first embodiment, first, the surface shape, the surface interval, the amount of eccentricity, the inclination with respect to the optical axis, the refractive index, the effective diameter, and the By changing only the parameters of the optical system made of an amorphous material such as the difference, the aberration of one component of the scalar in the optical performance of the projection optical system is corrected, and then the structure of the thin film and the birefringence of the optical member The aberration of the scalar single component and the polarization component may be corrected by changing parameters such as the distribution and the azimuth around the optical axis.

When the crystal axis orientation of the refraction member made of an equiaxed crystal material is optimized, not only polarization aberration but also scalar aberration remains. An aspherical surface for correcting this scalar aberration may be formed on the optical surfaces (lens surfaces, reflection surfaces) of some optical members. The aspherical surface may be used also as an aspherical surface for correcting residual aberration (typically a shape rotationally asymmetrical with respect to the optical axis) calculated in step S526 in the assembling process S5 described later. , May be provided separately. If provided separately, the aspherical shape (shape rotationally symmetric or rotationally asymmetrical with respect to the optical axis) is set as a design parameter in the design step S1. Next, the amorphous material preparing step S6 will be described. In this embodiment, quartz or fluorine-doped quartz (hereinafter referred to as modified quartz) is used as the amorphous material. Such quartz or modified quartz is in an ideal state unlike an optical crystal. Does not produce birefringence.

However, in the case of quartz or modified quartz, birefringence due to internal stress appears when impurities are mixed in or when a temperature distribution occurs when cooling quartz formed at a high temperature. Therefore, in the present embodiment, a desired birefringence distribution is generated in quartz or modified quartz by adjusting the amount and type of impurities mixed in the ingot or the thermal history.

The impurities include 〇H, Cl, metal impurities, and dissolved gas. In the case of the direct method, OH containing several hundred ppm or more, and then OH containing several tens ppm. Is considered to be dominant from the amount of contamination. When this impurity is mixed into the ingot, the coefficient of thermal expansion of the material changes.For example, when cooling after annealing, the part where the impurity is mixed shrinks greatly, and the difference in the shrinkage causes Stress occurs and stress birefringence occurs.

The thermal history exists regardless of the production method such as the direct method, the vapor axial deposition (VAD) method, the sol-gel method (sol-gel) method, and the plasma burner method.

In the present embodiment, a Si compound gas (a carrier gas such as 02 or H2 is used to send out the Si compound gas) as a raw material for quartz, and a combustion gas (O 2 gas and H 2 gas) for heating are used. Are discharged from the burner, and quartz is synthesized using a flame hydrolysis method in which quartz is deposited in the flame to obtain an ingot. Thereafter, the ingot is cut out to obtain a disc material, and the disc material is annealed (or gradually cooled). Then, in the present embodiment, the synthesis conditions at the time of synthesis of quartz and the thermal history conditions at the time of annealing are set so that the birefringence distribution of the refractive member made of quartz becomes the birefringence distribution calculated in the design step S1. And have adjusted. At this time, the bar of the synthesis condition And the swinging pattern of the target. Note that such a synthesis condition / anneal condition may be obtained by trial and error or may be determined using empirical rules.

In the present embodiment, the axis of symmetry of the birefringence distribution of an amorphous material made of, for example, quartz or modified quartz substantially coincides with the optical axis of a refractive member formed of the amorphous material. For this purpose, the ingot is synthesized while rotating the ingot during the synthesis of quartz, and the impurity concentration and the physical property distribution in the ingot are made centrally symmetric. Since the center position of the ingot (substantially coincides with the rotation center at the time of synthesis) becomes the center of the stress distribution, in the second refraction member forming step described later, the center position and the optical axis are matched based on this center position. It is preferable to form a refraction member. For this reason, it is desirable to mark the center position of the material cut out from the ingot. At the time of annealing, the raw material cut from the ingot is made into a cylindrical disk material and heated in the center of a furnace having a symmetrical temperature distribution. At this time, it is preferable to perform annealing while rotating the disk material.

Next, the birefringence amount measuring step S7 will be described. In this birefringence measuring step S7, the birefringence distribution of the amorphous material made of quartz or modified quartz obtained in the amorphous material preparing step S6 is measured. In the measurement of the birefringence distribution, a birefringence measuring instrument shown in FIG. 8 can be used, and the method of measuring the birefringence distribution is also as described above, and therefore the description is omitted here. It is preferable that information on the position of the axis of symmetry of the birefringence distribution obtained by this measurement be provided in the amorphous material by, for example, a method of marking a disc material.

In the birefringence measurement step, it is preferable to measure the refractive index distribution of the amorphous material. Hereinafter, a method for measuring the absolute value of the refractive index and the refractive index distribution of the amorphous material will be described with reference to FIGS. FIG. 12 is a diagram schematically showing an interferometer device for measuring the absolute value of the refractive index and the refractive index distribution.

In Fig. 12, a predetermined position in the sample case 13 2 filled with oil 13 1 The non-crystalline material 1 3 3 which is the object to be tested is set in the apparatus. The light emitted from the interferometer unit 135 controlled by the control system 134 is incident on a Fizeau flat (Fizeau plane) 135 supported on a Fizeau stage 135a.

Here, the light reflected by the Fizeau flat 1336 becomes the reference light, and returns to the interferometer unit 135. On the other hand, the light transmitted through the Fizeau flat 13 36 becomes measurement light, and is incident on the test object 13 3 in the sample case 13 2. The light transmitted through the test object 133 is reflected by the reflection plane 133 and returns to the interferometer cut 135 via the test object 133 and the Fizeau flat 136. Thus, the wavefront aberration due to the refractive index distribution of the amorphous optical member 133 is measured based on the phase shift between the reference light and the measurement light returned to the interferometer unit 135. For details of the measurement of the refractive index homogeneity by the interferometer, for example, Japanese Patent Application Laid-Open No. 8-55505 can be referred to.

Next, the second bending member forming step S8 of forming a bending member from an amorphous material will be described.

In the second refraction member forming step S8, a material obtained by grinding an amorphous material (typically a disc material) whose birefringence distribution or refractive index distribution was measured in the birefringence amount measurement step S7 as necessary. Is used to manufacture each lens that constitutes the projection optical system. In other words, the surface of each lens is polished in accordance with a well-known polishing process with the target of the surface shape and the surface interval in the design data, and a refraction member having a lens surface of a predetermined shape is manufactured. In this second refraction member forming step, similarly to the first refraction member formation step (the refraction member formation step S4 of the first embodiment), polishing is repeated while measuring the surface shape error of each lens with an interferometer. Then, bring the surface shape of each lens close to the target surface shape (best fit spherical shape). Thus, when the surface shape error of each lens falls within a predetermined range, the error of the surface shape of each lens is reduced in the same manner as in the first refraction member forming step (the refraction member forming step S4 of the first embodiment). For example, the measurement is performed using the precise interferometer shown in FIG. Also in the second refraction member forming step S8, the measured surface shape falls within a predetermined range. Repeat the measurement and polishing.

Next, the assembling step S5 in the second embodiment will be described with reference to FIG. FIG. 13 is a flowchart showing details of the assembling step S5 of the method for manufacturing a projection optical system according to the second example. In the flowchart, the judgment process is generally illustrated by a diamond, but in FIG. 13, the judgment process (for example, S5 14, S5 17, S5 22, S 5 2 3, S 5 3 2) are represented by hexagons as shown.

(Step S510) In step S510, information on the crystal axis of the refraction member made of the crystalline material measured in the crystal axis measurement step S3 and the information measured in the first refraction member formation step S4 Information on the surface shape and surface spacing of the processed refraction member, information on the refractive index and distribution of the refraction member made of an amorphous material measured in the birefringence amount measurement step S7, and information on the birefringence amount and distribution. (2) Refraction member forming step These parameters (surface shape, surface interval, refractive index, refractive index distribution, crystal The optical performance when assembling the projection optical system using the optical members having the axial orientation, the amount of birefringence, the birefringence distribution, etc., is predicted by simulation using a computer.

Specifically, first, after setting the parameters of each optical member of the projection optical system according to the design data obtained in the design process S1, the optical performance of the projection optical system by adding the above information to each optical member Is calculated. Here, as the evaluation value of the optical performance of the projection optical system, the average phase distribution, the retardation distribution, the RMS value, the PSF value, and the like described above can be used.

(Step S 5 11 1) In step S 511, the distance between the optical members virtually assembled in the simulation, the amount of eccentricity with respect to the optical axis, and the azimuth (incorporation angle) around the optical axis are changed. The optical performance of the projection optical system PL is calculated by simulation. The optical member manufactured through the above-described steps S2 to S4 and S6 to S8 has a non-uniform refractive index distribution / birefringence distribution, a surface shape, a plane interval, and a crystal axis orientation. Because of the fabrication error, the characteristics of the projection optical system PL change even when only the azimuth (embedded angle) around the optical axis of the optical member is changed. Here, the interval and the amount of eccentricity of each optical member and the mounting angle are optimized so as to obtain the best optical characteristics.

(Step S512) In step S512, the optimized distance between optical members, the amount of eccentricity, and the amount of installation are determined based on the distance and the amount of eccentricity of the optical members optimized by simulation and the angle of installation. Incorporate the optical member into the lens barrel that holds each optical member according to the angle. (Step S 5 13) In step S 5 13, the wavefront aberration is measured using the aberration measuring and measuring apparatus shown in FIG. The aberration measuring device shown in FIG. 14 uses the principle of the phase recovery method. In Fig. 14, the pattern forming surface of the pattern plate 141 is positioned on the object plane of the projection optical system PL, and the front side of the objective optical system 144 is positioned at the imaging position (image plane) of the projection optical system PL. Position the focal point. After that, the illumination light emitted from the illumination light source 140 illuminates the pinhole 142 formed on the pattern plate 141 to generate an ideal spherical wave. When this ideal spherical wave passes through the projection optical system PL, the ideal spherical wavefront shape changes under the influence of the aberration remaining in the projection optical system PL. The light that has passed through the projection optical system PL is condensed by the object optical system 144, and the image is captured by the imaging element 144. The intensity distribution changes. Therefore, the residual aberration of the projection optical system PL can be obtained by performing a predetermined operation based on the phase recovery method on the image signal including the information on the residual aberration aberration of the projection optical system PL. For details of the phase recovery method described above, see US Pat. No. 4,309,602.

In order to measure the residual aberration of the projection optical system PL, as shown in FIG. 14, the pinhorn 14 formed on the pattern plate 14 1 is arranged on the optical axis AX of the projection optical system PL. In addition to the above, it is necessary to measure the wavefront aberration in a state where the pinholes 142 are arranged at a plurality of measurement points (for example, several tens) in a plane orthogonal to the optical axis AX. Therefore, in this step, the pinhole 1 4 2 is set in the plane orthogonal to the optical axis AX. Is moved to the measurement point and the wavefront aberration is measured. Instead of moving the pattern plate 141, a plurality of pinholes are formed in the pattern plate 141, a member for defining an illumination area is provided in the illumination light source 140, and one pin at a time is provided. The wavefront aberration may be measured by illuminating the hole.

(Step S 5 14) In step S 5 14, it is determined whether or not the wavefront aberration can be measured at all the measurement points on the image plane of the projection optical system. The aberration measuring device shown in FIG. 14 performs a predetermined operation based on the phase recovery method on an image signal obtained by imaging with the image sensor 144 to reduce the residual aberration of the projection optical system PL. However, the phase recovery method cannot restore the wavefront if the residual aberration of the projection optical system PL is too large. Therefore, in step S514, it is determined whether the wavefront aberration can be measured at all the measurement points. If it is determined that there is at least one measurement point at which aberration cannot be measured (determination result is “NG”), the process proceeds to step S515.

(Step S 515) In step S 515, the adjustment of the interval of each optical member in the optical axis direction, the adjustment of the position of each optical member in the plane orthogonal to the optical axis (the eccentricity adjustment), and the light of each optical member By performing at least one of the adjustments of the azimuth around the axis, the optical performance of the projection optical system is adjusted, and the flow proceeds to step S513.

These steps S513 to S515 are repeated until it is determined in step S515 that aberration measurement is possible at all measurement points. Here, when it is determined in step S5 14 that aberration measurement is possible at all measurement points (when the determination result is “OK”), the process proceeds to step S5 16.

(Step S 516) In step S 516, the wavefront aberration at all measurement points is measured using the above-described aberration measuring device.

(Step S5 17) In step S5 17, it is determined whether or not the wavefront aberration measured in step S5 16 is within a predetermined standard. This step S 517 is a step of judging whether or not the optical performance of the projection optical system has been adjusted to the extent that highly accurate aberration measurement described later can be performed. If the result of this determination is "NG", step S5 The process proceeds to 18, and if the determination result is “OK”, the process proceeds to step S 5 19. (Step S 518) In step S 518, the adjustment of the interval of each optical member in the optical axis direction, the adjustment of the position of each optical member in the plane orthogonal to the optical axis (eccentricity adjustment), and the light By performing at least one of the adjustments of the azimuth around the axis, the optical performance of the projection optical system is adjusted, and the flow proceeds to step S 516.

(Step S5 19) By repeatedly executing the above steps S5 16 to S5 18, the optical performance of the projection optical system is adjusted to such an extent that highly accurate aberration measurement can be performed. Then, the flow shifts to step S 5 19.

In step S 519, for example, a Fizeau interferometer-type wavefront aberration measuring device disclosed in Japanese Patent Application Laid-Open No. H10-38957 and a method disclosed in Japanese Patent Application Laid-Open No. 2000-97616 are disclosed. High-precision wavefront aberration measurement using a PDI (Phase Diffraction Interferometer) type wavefront aberration measurement device.

At this time, in the present embodiment, the wavefront aberration is measured for each of a plurality of polarization components with respect to the projection optical system. Specifically, the XY polarization component, the R0 polarization component, and the like described above can be used. In the present embodiment, instead of or instead of measuring the wavefront aberration for each of a plurality of polarization components, measurement using a non-polarization component (for example, using the XY polarization component and the polarization component simultaneously) is performed. May be.

(Step S520) In Step S520, the expansion coefficient of each term is obtained by fitting the measured wavefront aberration to the Zell-Eke cylindrical function system Ζη (ρ, Θ), and the wavefront aberration is calculated. Is calculated (and, if necessary, each component of wavefront aberration for each polarization). '

Here, the fitting of the wavefront aberration using the Zernike cylindrical function system Ζ η (ρ, Θ) will be briefly described.

First, the polar coordinates on the exit surface are determined, and the wavefront aberration is expressed as W (ρ, Θ). Here, ρ is a normalized pupil radius obtained by standardizing the exit pupil radius to 1, and 0 is a radial angle in polar coordinates. Next, the wavefront aberration W (ρ, Θ) is converted into the Zernike cylindrical function system Ζ η (ρ, Using Θ), expand as shown in the following equation (6).

(6) W (, Θ) = ∑CnZn (, Θ) = C 1

Z l (p, Θ) + C 2 Z 2 (, Θ) + ■--.

+ CnZn (p, Θ) Since the cylindrical function system relating to each term of the Zelke's cylindrical function system Z n {ρ, θ) is well known, detailed description is omitted.

The projection optical system according to the present embodiment is provided with an external adjustment mechanism for adjusting optical performance (magnification, aberration, etc.) even after the projection optical system is mounted on the exposure apparatus main body. As such an external adjustment mechanism, a mechanism for controlling or manually adjusting the position and orientation of an optical member constituting the projection optical system, or a mechanism for manually adjusting the position and orientation, and the first surface among the optical members constituting the projection optical system There is a mechanism for exchanging an optical member located on the side and / or the second surface side with an optical member having optical characteristics different from the optical member.

Hereinafter, the external adjustment mechanism will be briefly described with reference to FIG. The projection optical system of the present embodiment has a configuration in which a plurality of optical members 21 to 27 are arranged along the optical axis direction (Ζ direction). The two optical members 22 on the W side are interchangeable with the main body of the projection optical system PL. The five lenses 23 to 27 of the plurality of optical members are respectively rotated by the actuators 28 to 32 in the direction of the optical axis (） direction) and the direction perpendicular to the optical axis (ΧΥ direction). (S x, 0 y direction) can be adjusted. Here, the holding member 33 that holds the optical member 22 closest to the second surface W is configured to be detachable from a part 34 of the lens barrel that forms the projection optical system PL.

In this embodiment, since five lenses can be adjusted in the Z direction, the θ X direction, and the 0 y direction, respectively, five rotationally symmetric aberrations (magnification, low-order distortion, low-order Aberration, low-order field curvature and low-order spherical aberration) and five eccentric aberrations (two types of eccentric distortion, eccentric coma, eccentric ass, and eccentric spherical aberration) can be corrected. In this embodiment, five lenses can be adjusted. However, the number of lenses whose position can be adjusted is not limited to five.

In this embodiment, at least one of the optical member closest to the first surface R and the optical member closest to the second surface W has a birefringence amount and a birefringence distribution different from those of the optical member. It can be replaced with an optical member. Here, as the optical member, an equiaxed crystal material manufactured by the same manufacturing method as the above-described crystal material preparing step S2, crystal axis measuring step S3, and first refraction member forming step S4 is used. (For example, fluorite or barium fluoride) or an amorphous material manufactured by the same manufacturing method as the above-described amorphous material preparation step S6, birefringence amount measuring step S7, and second refractive member forming step S8. Materials (quartz, modified stones) can be applied.

Further, the optical member closest to the first surface R and the optical member closest to the second surface W are positioned relative to the projection optical system PL in the XY plane and in the 0x and 0y directions. It is preferable that the tilt and the position in the Z direction can be adjusted. According to this configuration, for example, when rotationally asymmetric polarization aberration is generated in the projection optical system PL, the position and orientation of the optical member 21 or 22 having a predetermined birefringence distribution is adjusted, and the rotation is adjusted. Asymmetric polarization aberration can be corrected. Here, when the optical member closest to the second surface W is a plane-parallel plate, decentering coma can be corrected by adjusting the inclination in the θ, and Θy directions. In addition, if the refractive power of the optical member closest to the second surface W is adjusted (by replacing the optical member with a different refractive power), the Pebbles sum of the projection optical system PL can be adjusted. .

Although not shown in FIG. 15, an optical surface (a refractive surface, a reflective surface, or the like) having a toric surface shape is provided on a part of the optical member constituting the projection optical system PL, and the optical axis AX of the optical member is provided. By adjusting the surrounding azimuth, it is possible to correct the astigmatic difference on the optical axis.

(Step S 5 21) Returning to FIG. 13, in step S 5 21, when the projection optical system has the value of each component of the wavefront aberration calculated in step S 5 20, Simulate the wavefront aberration (or each component of the wavefront aberration) after adjustment using the external adjustment mechanism. Predict with a ration. Specifically, the values of the calculated components of the wavefront aberration are used as a starting point, and the parameters of the external adjustment mechanism (the movement amount of the lenses 23 to 27, the surface shape of the optical members 21 and Z or 22, (Thickness, refractive index, refractive index distribution, birefringence, birefringence distribution) are optimized, and the aberration of the projection optical system in the simulation after optimization is determined. In the case where optical members having different birefringence amounts and distributions are not replaced in the external adjustment mechanism, the predicted wavefront aberration may be a scalar component only.

(Step S522) In step S522, it is determined whether or not the aberration predicted by the simulation is within a predetermined standard. If the result of the determination in step S522 is "NG", the flow shifts to step S522. If the result of the determination in step S522 is "OK:", the flow shifts to step S529.

(Step S 5 2 3) In step S 5 2 3, the aberration predicted in step S 5 22 is adjusted by adjusting the interval of each optical member in the optical axis direction, and by adjusting the position of each optical member in the plane orthogonal to the optical axis. Adjustment (eccentricity adjustment) and adjustment of the azimuth of each optical member around the optical axis are performed to determine whether or not the correction can be performed. Here, if the result of the determination in step S 5 23 is “Ο Κ”, the process proceeds to step S 5 24, and if the result of the determination is “NG”, the process proceeds to step S 5 25. Transition.

(Step S 524) In step S 524, the adjustment of the interval of each optical member in the optical axis direction, the adjustment of the position of each optical member in the plane orthogonal to the optical axis (the eccentricity adjustment), and the light of each optical member By adjusting at least one of the adjustments of the azimuth around the axis, the aberration of the projection optical system is corrected, and the process proceeds to the wavefront aberration measurement in step S516.

These steps S 516 to S 524 can improve the optical performance of the projection optical system without forming an aspherical surface on the optical member of the projection optical system or replacing the optical member with a different birefringence distribution. This is the process to find out if you can drive.

If it is determined in step S523 that the correction of the aberration that is determined to be out of the standard cannot be performed only by adjusting the spacing, the eccentricity, and the azimuth of the optical members, the following is performed. Move on to step S525. (Step S 525) In step S 525, the adjustment of the interval of each optical member in the optical axis direction, the adjustment of the position of each optical member in the plane orthogonal to the optical axis (the eccentricity adjustment), and the light of each optical member After adjustment of the azimuth around the axis, the wavefront aberration (or each component of the wavefront aberration, and if necessary, each component of the wavefront aberration for each polarization) is predicted by simulation.

Specifically, the value of each component of the calculated wavefront aberration is set as an output point, and the distance adjustment amount, the eccentricity adjustment amount, and the azimuth angle adjustment amount of each optical member are optimized as parameters, and after optimization. Of the projection optical system is obtained.

(Step S 526) In step S 526, an aspherical shape and Z or birefringence that can correct the residual aberration (residual component of aberration) of the projection optical system predicted in step S 525 Calculate the distribution. In this step S526, an optical member that forms an aspheric surface and an optical member that changes Z or birefringence distribution are selected according to the aberration to be corrected.

FIG. 16A, FIG. 16B, and FIG. 16C are diagrams for explaining an optical member having an aspheric surface and / or an optical member having a changed birefringence distribution. The projection optical system PL shown in FIG. 16A is simplified in illustration, and has an optical member e 1 having a negative refractive power and an optical member e having a positive refractive power in order from the first surface R side. 2. It has an optical member e3 having a negative refractive power, an aperture stop AS, and an optical member e4 having a positive refractive power. Consider an optical path when light from two different object points Q 1 and Q 2 on the first surface R passes through the projection optical system PL. In the figure, reference numeral L1 denotes an optical path of a light beam emitted from the object point Q1, and reference numeral L2 denotes an optical path of a light beam emitted from the object point Q2. The light from the object point Q1 located at the intersection of the optical axis Ax of the projection optical system PL and the first surface R is diverged or converged each time it passes through the optical members e1 to e4, and the optical axis A An image is formed at the intersection of x and the second surface W. Here, the effective diameters of the optical members e1 to e4 are ψ1 to φ4. Further, the light beam diameter of the light beam L1 when passing through each optical member el to e4 is φLl1 to φL14, and the light beam diameter of the light beam L2 when passing through each optical member el to e5 is φL21 to φL24.

Considering the optical path when the light beams LI and L2 pass through the optical member e1, the optical member The ratio of the luminous flux diameter φ1 to the effective diameter φ1 of e1 and the luminous flux diameter of the optical member e1 to the effective diameter φ1 (the ratio of i> L21 is about 0.25, and the luminous flux L1 Is different from the position where the light beam L 2 passes through the optical member e 1 and the position where the light beam L 2 passes through the optical member e 1. Next, consider the optical path when the light beams L l and L 2 pass through the optical member e 4. The ratio of the luminous flux diameter <i> L15 to the effective diameter φ4 of the optical member e4 and the ratio of the luminous flux diameter 0L24 to the effective diameter φ4 of the optical member e4 are almost equal to 1. The position where the light beam L1 passes through the optical member e4 is substantially the same as the position where the light beam L2 passes through the optical member e4. When calculating the aspherical surface and calculating the birefringence amount and distribution of the optical members in the projection optical system PL, consider the light path described with reference to Fig. 16A. It is necessary to select the optical member can be corrected effectively aberration Te.

For example, when correcting for high image plane coordinate dependency and correcting aberrations (scalar aberrations such as distortion and field curvature, and polarization aberrations (influence of birefringence) that varies depending on the image plane coordinates), the object point Q 1 An aspherical surface is provided on the optical surface (lens surface, reflection surface, etc.) of the optical member e1 that passes through the position where the light beam L1 and the light beam L2 from the object point Q2 are separated, or the optical member e1 is duplicated. By changing the refractive index distribution, aberrations highly dependent on image plane coordinates can be effectively corrected.

When correcting aberrations highly dependent on pupil coordinates (for example, scalar aberrations such as spherical aberration and decentered coma, and polarization aberrations (effect of birefringence) with little dependence on image plane coordinates), the correction is performed from the object point Q1. When an aspherical surface is provided on the optical surface of the optical member e4 through which the light beam L1 of the optical member L1 and the light beam L2 from the object point Q2 pass almost over the entire surface, or the birefringence distribution of the optical member e4 is changed, the pupil coordinates Highly dependent aberrations can be effectively corrected.

For aberrations (for example, coma aberration) whose image plane coordinate dependency and pupil coordinate dependency are almost equal, the degree of superposition of the light flux L1 from the object point Q1 and the light flux L2 from the object point Q2 is small. An aspherical surface is provided on the optical surface of the intermediate optical member (for example, optical member e2, etc.), or the degree of superposition of the light flux L1 from the object point Q1 and the light flux L2 from the object point Q2 is intermediate. By changing the birefringence distribution of a target optical member (for example, the optical member e2, etc.), it is possible to effectively correct aberrations whose image plane dependence and pupil coordinate dependence are almost equal. Therefore, in step S526, an aspherical shape is calculated for the optical surfaces of at least three of the plurality of optical members e1 to e4 in the projection optical system PL in order to correct scalar aberration. Is preferred. As for the correction of the polarization aberration (the effect of birefringence), since the polarization aberration (the effect of the birefringence) with high pupil coordinate dependency (low image plane coordinate dependency) often occurs, the projection optical system PL It is preferable to calculate the amount of birefringence and the distribution of at least one of the plurality of optical members e1 to e4.

Here, in an optical member made of an amorphous material having such a birefringence amount and distribution, the effective diameter of the optical member is Φc, and a light beam emitted from a predetermined point on the first surface R is an optical member. When the luminous flux diameter when passing through the member is ΦP,

(7) 0.6 <φ ρ / φ ο≤ 1

Is preferably arranged at a position that satisfies the following. By arranging the optical member having the predetermined birefringence distribution at a position satisfying the expression (7), the polarization aberration (influence of birefringence) caused by the refraction member made of an equiaxed crystal material can be reduced. It can be corrected effectively. In order to more properly correct the polarization aberration (the effect of birefringence), it is preferable to set the lower limit of the above expression (7) to 0.7.

In addition, an optical member made of an amorphous material having a birefringence amount and distribution for correcting polarization aberration (influence of birefringence) having high pupil coordinate dependency (low image plane coordinate dependency) includes a projection optical system. It is preferable to be arranged at a position within 15 O mm from the pupil position.

Also, in order to more effectively correct aberrations such as coma aberration and the like that are almost equivalent to the image plane coordinates and the pupil coordinates, the light flux L 1 from the object point Q 1 and the light flux L from the object point Q 2 Since it is desirable to calculate the aspherical shape related to the optical surfaces of the two optical members where the degree of superposition of 2 is intermediate, in step S526, the plurality of optical members e1 to e in the projection optical system PL are calculated. e is aspherical with respect to the optical surface of at least four of the optical members More preferably, the shape is calculated.

The aspherical surfaces formed on the optical members e1 to e4 may be symmetric or asymmetric with respect to the optical axis Ax. Further, an aspherical surface may be formed irregularly (randomly) according to the generated aberration. Similarly, the birefringence distribution provided in the optical members el to e4 may be either symmetric or asymmetric with respect to the optical axis Ax, and may be irregular (random) birefringence depending on the generated aberration. It may have a distribution.

Here, the aspherical surface, the amount of birefringence, and the distribution calculated in step S526 are not necessarily intended to correct all the wavefront aberrations remaining in the projection optical system PL. The purpose may be to correct only the residual aberration. For example, the wavefront aberration that can be corrected by the external adjustment mechanism described later may be corrected by the external adjustment mechanism without being intentionally corrected in step S526. In addition, among the residual wavefront aberrations of the projection optical system PL, those that can be ignored in view of the imaging performance need not be corrected by forming an aspheric surface or adding a birefringent distribution.

(Step S 5 2 7) Returning to FIG. 13, in step S 5 27, the optical surface (lens surface, reflection surface, etc.) of the optical member selected in step S 5 26 is replaced with step S 5 2

Processing is performed to obtain the aspherical shape calculated in 6. When the birefringence distribution of a predetermined optical member is changed in step S526, an optical material having the birefringence amount and distribution calculated in step S526 is prepared, and this optical material is prepared. Process materials.

(Step S528) In step S528, an optical member having a predetermined aspherical surface and an optical member having a predetermined birefringence and distribution are assembled into a projection optical system. At this time, an assembling error may occur.However, the assembling error generated here is considered to be not so large as to be impossible to measure with the aberration measuring device shown in FIG. In the example, the process shifts to step S 5 16.

(Step S 5 2 9) By the way, in Step S 5 2 2, when the aberration predicted by the simulation is within a predetermined standard (when the judgment result is “OK”) In this case, since the optical characteristics of the projection optical system PL have been adjusted to such an extent that they can be finely adjusted by an external adjustment mechanism, the external adjustment mechanism is attached and its initial adjustment is performed. Here, in the initial adjustment of the external adjustment mechanism, processing for adjusting the response amount to the control signals of the actuators 28 to 32 shown in FIG. 15 is performed. Specifically, for example, when a control signal for extending 1 μπι is output to the actuators 28 to 32 from a control system (not shown), the actuators 28 to 32 output 1 / zm according to the control signal. Since the extension may not occur, the response amount of the actuators 28 to 32 to the control amount by the control system is adjusted. Here, since the control signal output from the control system is a signal that varies the optical performance of the projection optical system PL, this initial adjustment is performed by adjusting the amount of adjustment by the external adjustment mechanism and the performance of the projection optical system PL. This is a process for obtaining a correlation with the quantity. When the actuators 28 to 32 are attached, only adjustment using the external adjustment mechanism is performed.

(Step S530) When the above step S529 is completed, the wavefront aberration is measured using the wavefront measuring device used in step S516 described above. At this time, similarly to the above-described step S520, the Zernike cylindrical function system Znp, に対して) is fitted to the wavefront aberration measurement result to obtain an expansion coefficient Cn (Zernike coefficient) for each term. Processing for calculating the component of the wavefront aberration may be performed.

(Step S 531) When the above step S 531 is completed, it is determined whether or not the projection optical system is within a predetermined tolerance. If the result of the determination in step S 531 is “NG”, the flow proceeds to step S 5 32. If the result of the determination in step S 531 is “OK”, the manufacture of the projection optical system PL is completed.

(Step S 5 32) In step S 5 32, adjustment using the above-described external adjustment mechanism is performed, and the flow advances to step S 5 29. Here, steps S529 to S532 are repeated until the determination result of step S530 becomes "OKj".

In the assembling process of the second embodiment described above, the adjustment is performed using the wavefront aberration of a plurality of polarization components, but the wavefront aberration may be measured using only the non-polarization component. In this case, since only the scalar component of the wavefront aberration is known, the parameter of the optical member that affects the polarization component of the wavefront aberration is correlated with the change in the scalar component of the wavefront aberration. Based on this, the parameters of the optical member may be changed in each step.

As described above, according to the method for manufacturing a projection optical system according to the second embodiment, the influence of birefringence caused by an equiaxed crystal material such as fluorite or barium fluoride is applied to a plurality of polarization components. During the evaluation, the incorporation angle of the crystal axis of the refraction member made of this equiaxed crystal material was determined so that the effect of birefringence (polarization aberration) was minimized, and only the optimization of the crystal axis direction was performed. Since the effect of birefringence (polarization aberration) that cannot be completely corrected can be compensated by the amorphous refraction member, good optical performance can be secured.

Next, as a third embodiment, an exposure apparatus including a projection optical system manufactured according to the first or second embodiment will be described with reference to FIG. FIG. 17 is a diagram schematically showing an exposure apparatus according to the third embodiment.

In FIG. 17, for example, a pulse light from a light source 40 composed of an ArF excimer laser that supplies a pulse light having a wavelength of 193 nm travels along the X direction and is deflected by an optical path bending prism 41. Then, a diffractive optical element (DOE) provided on the DOE turret 42 is provided. The DOE turret 42 is provided with a plurality of diffractive optical elements of different types. These diffractive optical elements have a predetermined cross-sectional shape in a far field region of the diffractive optical element, for example, a circular cross section, an annular cross section, a multipole cross section (a plurality of eccentric sections with respect to the reference optical axis). The incident light beam is converted so that the light beam has the following pole.

The divergent light beam from the diffractive optical element is condensed by the condenser lens group 43, and forms a far-field area of the diffractive optical element near the position of the micro fly's eye lens 44. Here, the micro fly's eye lens 4 is formed by integrally forming a plurality of lens surfaces arranged in a two-dimensional matrix on one or a plurality of substrates. Things. Instead of the micro fly's eye lens 44, a fly's eye lens having a plurality of lens elements integrated in a two-dimensional matrix may be used. Further, a condenser lens group disposed between the diffractive optical element and the micro fly's eye lens 44 includes a zoom optical system capable of continuously changing the focal length by moving the lens in the optical axis direction, It is preferable to use a variable power optical system such as a multifocal length optical system that can change the focal length discontinuously by exchanging lenses. A secondary light source (surface light source) composed of a plurality of light source images is formed on the exit surface side of the micro fly's eye lens 44. Note that virtual images of a plurality of light sources may be formed at the position of the incident surface of the micro fly's eye lens 44 (or fly's eye lens).

The light from the secondary light source is condensed by the condenser optical system 45 and illuminates the variable field stop 46 in a superimposed manner. Then, the light from the variable field stop 46 is used as a blind imaging optical system 47 a through which the aperture of the variable field stop 46 and the reticle R as a projection original plate arranged on the first surface are almost shared. Reticle R is reached via 4 7 c. In this embodiment, two optical path bending mirrors 48a and 48b are arranged in the blind imaging optical systems 47a to 47c to deflect the optical path by approximately 180 °. ing. For example, a slit-shaped illumination field is formed in a part of the pattern formation area on the reticle R by the light from the blind imaging optical systems 47a to 47c. The light from this illuminated field passes through the projection optical system PL obtained by the manufacturing method of the first or second embodiment described above and passes through a work piece (photosensitive substrate) arranged on the second surface of the projection optical system. Then, the wafer W is formed, and an image of the pattern in the slit-shaped illumination field is formed on the wafer W. In the present embodiment, the reticle stage RS supporting the reticle R on the first surface and the wafer stage supporting the wafer W on the second surface are movable in the Y direction, and the magnification of the projection optical system is changed. By performing exposure while moving the reticle stage RS and the wafer stage WS at the ratio of the magnification jS, a slit-shaped imaging region is swept in the Y direction on the wafer WS. , Typically a rectangular A pattern image of the reticle R in the pattern formation region is formed in the region.

After the scanning exposure on one shot area is completed, the wafer stage WS is driven to perform scanning exposure on another shot area, and a plurality of shot areas are formed on almost the entire surface of the wafer W.

In this embodiment, an example is shown in which the projection optical system manufactured by the manufacturing method of the first and second embodiments is applied to a scanning exposure apparatus. The manufactured projection optical system can be applied to a batch exposure type projection exposure apparatus.

Further, in the projection exposure apparatus of the present embodiment, at least a part of the illumination optical system 41 to 47 c for illuminating the reticle R as the projection original plate arranged on the first surface based on the light from the light source, In particular, an optical member made of an equiaxed crystal material (for example, fluorite) is used in a portion where light energy is increased. In such an illumination optical system, the required optical performance is lower than that of the projection optical system. Therefore, in this embodiment, the crystal axis orientation of the equiaxial crystal material in the illumination optical system is optimized. We did not reduce the effect of birefringence (polarization aberration).

However, when the optical performance required for the illumination optical system is high, the crystal axis orientation of the equiaxed crystal material is optimized or the non-crystal The influence of birefringence (polarization aberration) caused by the equiaxial crystal material may be corrected by an optical member made of a material.

Further, in the present embodiment, the wavelength 1 9 3 nm of pulsed light is applied to A r F excimer laser for supplying the light source as the light source, for example, F ₂ laser which supplies the path light of wavelength 1 5 7 nm , it can also be applied K r ₂ laser supplying light of wavelength 1 4 7 nm, the a r ₂ laser supplying light of wavelength 1 2 6 n ln.

For example, when the pulsed light having a wavelength of 1 5 7 nm were applied F ₂ laser which supplies a light source, a light transmitting member in the illumination optical system 4 1 to 4 7 c, equiaxed fluorite or the like fluoride Bariumu Crystalline crystalline materials and fluorine-doped quartz (modified quartz) can be used. In particular, as the optical material of the micro fly's eye lens 44, force [1 It is preferable to use modified quartz in consideration of ease of use and shortness of the glass path.

Next, as a fourth embodiment, a projection optical system using a twin refraction member will be described. FIG. 18 is a diagram schematically showing the projection optical system of the fourth embodiment. The projection optical system of the fourth embodiment described below is also applicable as the projection optical system of the projection exposure apparatus of the third embodiment.

FIG. 18A shows a schematic configuration of a projection optical system including a refraction member 51 made of a twin crystal and a refraction member 52 made of an amorphous material, and FIG. 18B shows a crystal 5 in the refraction member 51. FIG. 18C shows the crystal axis of crystal 51 b in refraction member 51. The coordinate systems in FIGS. 18A, 18B and 18C are common as shown.

As shown in FIG. 18A, FIG. 18B and FIG. 18C, the twin refraction member 51 is composed of two crystals 5 1a of the same phase that are in contact with each other with a twin plane or twin boundary 50S as a boundary. , 5 1b are oriented 180 ° rotated around a predetermined common low-index crystal axis (in this embodiment, crystal axis [1 1 1]), or are in contact with each other The two crystals of the phase are mirror images of a given crystal plane (the {111} plane in this example).

In this configuration, in the twin refraction member 51, the crystal axes [1 1 1] of the two crystals 5 la and 5 1 coincide with the optical axis Ax, and the crystal 5 1b corresponds to the crystal 5 1a. Is rotated 180 ° around the optical axis Ax in the XY plane. This is because the crystal axes [1 1 1] of the two crystals 51a and 51b coincide with the optical axis Ax, and the crystal 51b is positioned on the XY plane with respect to the crystal 51a. In this case, the effect of birefringence (polarization aberration) is reduced by the crystal 51a and the crystal 51b for the same reason as in the projection optical system shown in FIG. 11 described above. Can cancel each other out. At this time, the influence of the birefringence (polarization aberration) that cannot be completely canceled by the crystals 51a and 51b can be corrected by the optical member 52 made of an amorphous material as in the above-described embodiment. It is. As described above, in this embodiment, the deterioration of optical performance due to intrinsic birefringence in the entire crystal refraction member is exploited by utilizing the fact that the influence of birefringence is opposite to each other before and after a twin plane or a twin boundary. It is possible to reduce. This makes it possible to ensure the optical performance of the projection optical system.

By the way, in the above-described embodiment, the crystal axis of the optical member made of an equiaxed crystal material [1

Although an example in which [1 1] is matched with the optical axis is shown, the crystal axis to be matched with the optical axis is not limited to the crystal axis [1 1 1] and a crystal axis equivalent to the crystal axis [1 1 1]. .

Hereinafter, as a fifth embodiment, of a plurality of refraction members made of an equiaxed crystal material, a predetermined first group of optical axes is optically defined as the crystal axis [100] or the crystal axis [100]. The optical axis of the predetermined second group, which is different from the first group, is substantially coincident with the crystal axis [100] or a crystal axis optically equivalent to the crystal axis [100]. An example in which the first and second units are relatively rotated by 45 ° about the optical axis will be described.

FIG. 19 is a diagram for explaining the method of the fifth embodiment, and shows the distribution of birefringence with respect to the incident angle of a light ray, similarly to FIGS. 11B and 11C described above. In the method of the fifth embodiment, the distribution of birefringence in the first group of refraction members is as shown in FIG. 19 (a), and the distribution of birefringence in the second group of refraction members is shown in FIG. 19 (b). It becomes as shown in. As a result, the distribution of birefringence in the whole of the first group of refraction members and the second group of refraction members is as shown in FIG. 19 (c).

Referring to FIGS. 19 (a) and 19 (b), in the method of the fifth embodiment, the region corresponding to the crystal axis [100] coincident with the optical axis is relatively large. This is a region having a refractive index and no birefringence. The regions corresponding to the crystal axes [1 1 1], [1-1 1], [1 1 1-1], [1 1-1] are the regions with relatively small refractive index and no birefringence. Become. Furthermore, the regions corresponding to the crystal axes [1 0 1], [1 0-1], [1 10], [1-10] have relatively large refractive indices for polarized light in the circumferential direction (0 polarized light). The birefringence region has a relatively small refractive index for radially polarized light (R-polarized light). in this way, It can be seen that the lens elements of each group are maximally affected by birefringence in the region of 45 ° from the optical axis (the angle between the crystal axis [100] and the crystal axis [101]). On the other hand, referring to (c) of FIG. 19, the first group of refraction members and the second group of refraction members are relatively rotated about the optical axis by 45 ° to thereby obtain the first group of refraction portions. The effect of the crystal axes [1 0 1], [1 0-1], [1 1 0], and [1 _ 1 0], where the birefringence is the largest, on the whole and the second group of refraction members A birefringent region that is thinned and has a larger refractive index for circumferentially polarized light (Θ-polarized light) than that for radially polarized light (R-polarized light) in a region 45 ° from the optical axis, that is, a region far from the optical axis. Will remain. In this case, in a general projection optical system, the maximum angle between the optical axis and the light beam in each lens element is about 35 ° to 40 °. Therefore, by employing the method of the fifth embodiment, the effect of the birefringence of the crystal axes [101], [101-1], [110] and [1-110] is substantially reduced. Good imaging performance can be ensured without receiving. In the above description, the first group of refraction members and the second group of refraction members each have one or more refraction members. When the first group of bending members or the second group of bending members include a plurality of bending members, the plurality of bending members are not necessarily limited to adjacent bending members. The concept of the group of refracting members in the present embodiment is the same for the refracting members of the third to sixth groups described later. In the method of the fifth embodiment, it is preferable that the total thickness of the first group of bending members along the optical axis is substantially equal to the total thickness of the second group of bending members along the optical axis.

By the way, referring to FIG. 11B (c) and FIG. 19 (c), the birefringence direction in the region of 3.5.26 ° from the optical axis in the method of FIG. The direction of birefringence in a region 45 ° from the optical axis in the method of the embodiment is opposite. Therefore, by adopting a method that combines the method of the fifth embodiment with the method described in FIGS. 11A, 11B and 11C, it is possible to obtain a good A high imaging performance can be ensured.

Next, as a sixth embodiment, the method of the above fifth embodiment, FIG. 11A, FIG. 11B and FIG. An example in which the method described in 1c is combined will be described.

According to the method of the sixth embodiment, the optical axis of a predetermined first group of refraction members among a plurality of refraction members made of an equiaxed crystal material is set to the crystal axis [100] (or the crystal axis [1 00] and the optical axis of the second group of refraction members different from the first group is optically aligned with the crystal axis [100] (or the crystal axis [100]). The first group of refracting members and the second group of refracting members are rotated relative to each other by 45 ° about the optical axis. Further, the optical axis of the predetermined third group of refraction members is set to the crystal axis [1 1 1]

(Or the crystal axis optically equivalent to the crystal axis [111]), and the optical axis of the fourth group of refraction members different from the third group is set to the crystal axis [111] (or the crystal axis). The third group of refraction members and the fourth group of refraction members are rotated relative to each other by 60 ° about the optical axis.

Here, the crystal axes optically equivalent to the crystal axis [1 1 1] are the crystal axes [—1 1 1], [1 1 1 1], and [1 1 1]. According to the method of the sixth embodiment, the total thickness of the first group of refracting members along the optical axis is substantially equal to the total thickness of the second group of refracting members along the optical axis; It is preferable that the total thickness of the refraction members along the optical axis be substantially equal to the total thickness of the fourth group of refraction members along the optical axis.

Next, as a seventh embodiment, the optical axis and the crystal axis [100] (or the crystal axis [100]) of at least one of the plurality of refraction members made of an equiaxed crystal material are used. A crystal axis that is optically equivalent to the above) will be described.

Referring to (a) of FIG. 11B and (b) of FIG. 11B, since the optical axis and the crystal axis [1 1 1] of the refraction member are matched, the crystal axis having the maximum birefringence [ The areas corresponding to [1 1 0], [1 0 1], and [0 1 1] exist at a pitch of 1 20 °, and the effect of birefringence having a distribution of 30 in the pupil plane, ie, the image plane (wafer) It is considered that an effect such as the occurrence of coma aberration appears on the surface.

On the other hand, referring to (a) of FIG. 19 and (b) of FIG. 19, since the optical axis of the refraction member and the crystal axis [100] match, the crystal having the largest birefringence is obtained. Axis [1 0 Regions corresponding to [1], [1 0-1], [1 10], and [1 1 1 0] exist at 90 ° pitch, and the influence of birefringence having a distribution of 4 mm in the pupil plane is appear.

In this case, since the vertical and horizontal patterns are dominant in the pattern to be projected on the wafer, if the distribution is 4 mm, the vertical and horizontal patterns are not affected by astigmatism. The collapse of the image does not become noticeable. Therefore, among a plurality of refraction members made of an equiaxed crystal material, the optical axis and the crystal axis [100] of at least one refraction member (or optically equivalent to the crystal axis [100]) By adopting the method of the seventh embodiment that matches the crystal axis, good imaging performance can be secured without being substantially affected by birefringence.

Next, as an eighth embodiment, among a plurality of refraction members made of an equiaxed crystal material, the optical axis of a predetermined fifth group is defined as a crystal axis [110] or the crystal axis [110]. The optical axis of the predetermined sixth group, which is different from the fifth group, is made substantially coincident with the optically equivalent crystal axis, and the optical axis of the crystal axis [110] or the crystal axis [110] is optically equivalent. An example will be described in which the fifth group and the sixth group are relatively rotated by 90 ° about the optical axis so that they substantially coincide with the crystal axis.

FIG. 20 is a diagram for explaining the method of the eighth embodiment of the present invention, and shows the distribution of birefringence with respect to the incident angle of a light ray, similarly to FIGS. 11B and 11 to 19 described above. . In the method of the eighth embodiment, the distribution of birefringence in the fifth group of refraction members is as shown in FIG. 20 (a), and the distribution of birefringence in the sixth group of refraction members is shown in FIG. It becomes as shown in. As a result, the distribution of birefringence in the whole of the fifth group of refraction members and the sixth group of refraction members is as shown in FIG. 20 (c).

Referring to FIG. 20 (a) and FIG. 20 (b), in the method of the eighth embodiment, the region corresponding to the crystal axis [1 10] coinciding with the optical axis is located in one direction. The birefringence region has a relatively large refractive index for polarized light and a relatively small refractive index for polarized light in the other direction (a direction orthogonal to one direction). The region corresponding to the crystal axes [100] and [010] is a region having a relatively large refractive index and no birefringence. Further In addition, the region corresponding to the crystal axes [111] and [111] is a region having a relatively small refractive index and no birefringence.

On the other hand, referring to (c) of FIG. 20, the refractive index of the fifth group and the refractive group of the sixth group are 90 around the optical axis. By rotating them relatively only, the entire refracting member of the fifth group and the refracting member of the sixth group have almost no influence on the crystal axis [110] where the birefringence is maximum, and the optical axis does not. The vicinity is a region having an intermediate refractive index and no birefringence. That is, when the method of the eighth embodiment is adopted, good imaging performance can be secured without being substantially affected by birefringence.

Also in the method of the eighth embodiment, it is preferable that the total thickness of the fifth group of refraction members along the optical axis is substantially equal to the total thickness of the sixth group of refraction members along the optical axis. In particular, in the method of the eighth embodiment, since the birefringent region is located at the center (the optical axis and its vicinity), it is more preferable to apply the method to a thin negative lens at the center.

It should be noted that one method appropriately selected from the four methods described above may be employed, or a plurality of methods selected from the four methods may be employed in combination. Further, in the case of a refraction member made of an equiaxed crystal material, when the maximum angle of a light beam passing through the refraction member with respect to the optical axis exceeds 20 °, birefringence is performed regardless of the arrangement position. Susceptible to. Therefore, for a refraction member made of an equiaxed crystal material in which the maximum angle of the passing light beam with respect to the optical axis exceeds 20 °, FIG. 11A, FIG. 11B and FIG. It is preferable to apply the method described in (1) or the method described in the fifth to eighth examples alone or in combination. With this configuration, the influence of birefringence can be further reduced, and good optical performance can be secured.

Also, in a projection optical system having a large image-side numerical aperture, the pupil position (the pupil position closest to the image side (second surface side in the case of a multiple-imaging optical system having an intermediate imaging point)) is closer to the second surface. In the lens located on the side, the maximum angle of the passing light beam with respect to the optical axis tends to be large. Therefore, for the refraction member formed of an equiaxed crystal material among the refraction members arranged between the pupil position closest to the second surface and the second surface, the method shown in FIG. number 5 It is preferable to apply the methods shown in the eighth to eighth embodiments individually or in combination. With this configuration, the influence of birefringence can be further reduced, and good optical performance can be ensured.

Also, among a plurality of refraction members made of an equiaxed crystal material, a seventh group of light transmitting members formed so that a predetermined crystal axis and an optical axis substantially coincide with each other; The eighth group of light transmitting members formed so that their axes substantially coincide with each other is defined as the glass path length when the light beam corresponding to the maximum numerical aperture of the projection optical system passes through the seventh group of light transmitting members. Let L7 be a path length when a ray corresponding to the maximum numerical aperture of the projection optical system passes through the eighth group of light transmitting members, and let L be a predetermined wavelength; It is preferable to satisfy the following conditional expression: IL 7−L 8 \ / λ <3 X 10 + ⁵ According to this configuration, even in a projection optical system having a large image-side numerical aperture, the effects of birefringence can be reduced by the light transmitting members of the seventh and eighth units. In order to further reduce the influence of birefringence, it is preferable to set the upper limit of Expression (9) to 2.6 × 10 ^{+ 5} . Hereinafter, embodiments based on specific numerical values will be described.

FIG. 21 is a diagram showing a lens configuration of a projection optical system according to Example 1 of the present invention. The projection optical system of this embodiment uses quartz SiO ₂ and fluorite C a F ₂ as optical materials, and an image of the reticle R arranged on the first surface is arranged on the second surface. Project on W.

The projection optical system includes, in order from the reticle R side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a third lens group having a positive refractive power. Has G3. Here, the first lens group G1 includes a lens LP11 formed of fluorite and having a positive refractive power. The third lens group G3 includes lenses LP12, LP13, LP14, and LP15 formed of fluorite. The aperture stop AS is arranged in the third lens group G3. The reference wavelength of the projection optical system of the first embodiment is 193.3 nm (ArF excimer laser), and is an optical system that is telecentric on both sides. Now, in the first embodiment, the first lens group G1 having a positive refractive power is The telecentric luminous flux emitted from the second lens group G2 is relayed to the second lens group G2, and a positive distortion is generated in advance, whereby the negative distortion generated by the second and third lens groups G2 and G3 is reduced. Has been corrected. The second lens group G2 having a negative refractive power mainly contributes to the correction of the Bebbar sum and realizes the flatness of the image plane. The third lens group G3 having a positive refractive power is based on the luminous flux relayed from the second lens group G2, and telecentrically forms an image on the second surface while suppressing the generation of spherical aberration as much as possible. It plays the role of forming an image under a luminous flux.

It is known that the quartz glass material causes irradiation fluctuation such as absorption and compaction with respect to the ArF laser. Here, by using at least one or more fluorite glass material for the first lens group having a positive refractive power, it becomes possible to suppress the deterioration of the irradiation fluctuation caused by the quartz glass material. In the first lens group, the luminous flux (partial diameter) passing through the center of the optical axis and the luminous flux passing through the periphery are relatively far from each other on the lens surface. In the area, the difference between the center and the periphery becomes noticeable, and the aberration fluctuation increases. Therefore, by using fluorite for the first lens group G1, it is possible to efficiently suppress aberration degradation due to irradiation fluctuation. In the projection optical system according to the present embodiment, it is desirable that at least one of the lens components formed of fluorite in the first lens group G1 has a positive refractive power. As described above, the influence of aberration degradation due to irradiation variation such as coma caused by the first lens group G1 and the difference between the center and the periphery of the projection area is greater than that caused by other lens groups. In particular, with a convex lens, the optical path length passing through the glass material is longer in the light beam passing through the center of the optical axis than in the peripheral light beam, and is therefore more susceptible to fluctuations in the irradiation of the glass material. As described above, it is desirable to use the fluorite glass for a lens having a positive refractive power from the viewpoint of efficiently controlling aberration fluctuation due to irradiation fluctuation. Also, from the viewpoint of achromatism due to the difference in refractive index from quartz, it is desirable to use fluorite glass for lenses having a positive refractive power.

The third lens group G3 includes a lens component formed of at least one fluorite. It is preferred to have a minute. In the projection optical system of the present embodiment, the luminous flux diverged by the second lens group G2 is converged by the third lens group G3, so that the irradiation energy density of each lens of the third lens group G3 is high. Become. This causes compaction, a type of irradiation variation. If fluorite glass material is used for the third lens group, the effect of reducing the effect of this compaction can be obtained. Furthermore, if fluorite glass is used for thick glass near the surface where the irradiation energy density is concentrated, compaction can be corrected more efficiently.

Table 1 below shows the specification values of the projection optical system according to the first example. In Table 1, 3 indicates the projection magnification (lateral magnification), NA indicates the numerical aperture on the image side (second surface side), and B indicates the diameter of the image circle on the image plane. In Table 1, the surface numbers indicate the order from the reticle side along the direction in which light rays travel from the reticle surface, which is the object surface (first surface), to the wafer surface, which is the image surface (second surface). , R indicates the radius of curvature of each surface (vertical radius of curvature in the case of an aspheric surface), and d indicates the surface interval of each surface on the optical axis.

Table 2 shows the aspheric coefficient for each aspheric surface. For an aspheric surface, let y be the height in the direction perpendicular to the optical axis, and let Z be the distance (sag amount) along the optical axis from the tangent plane at the vertex of the aspheric surface to a position on the aspheric surface at height y. Where r is the radius of curvature at the apex, K is the conic coefficient, and A to F are the n-th order aspherical coefficients, the following equation (10) is obtained.

(1 0) Z = (y 2 / x) {1-(1 + K)-y 2 / r 2} 1/2] + Ay4 + B ■ y6 + Cy8 + D ■ y 10+ E · y 12+ F

Em described in the column of each aspheric coefficient in 2 represents 10 m. Here, mm can be used as an example of the unit of the radius of curvature and the surface interval in the specification values of the present embodiment. The refractive index of each glass material at a wavelength of 193.3 nm is shown below. Si0 ₂ 1.5 6 0 326 1

CaF 2 1.5 0 14 5 48 Cn ί_π

ο CO o HW ¾ o ^ Rin>

CTi

00 ω CO CO O CJi 00

-J Cn o o On Cn

o O C o O Cn

o t \ j ω CJI O o cn o O CJi IV) O 0

-J o o o n Ol

cn ω o in in H-

H- H- 〇〇〇〇

〇〇〇〇 ho

s〇i

n

ω

o I— 1 GO Cn Cn Cn Cn ro t

CO ro Cn CO CO O

I) 00

ω -J Ω ω (_Π CO) O

Ji O ο -J 00

SiO [Surface number 2]

K = 0.000000

Α = -0.106010E-06

Β = 0.204228Ε-11 C = -0.588237E-16

D = 0.112269E-20

[Surface number 14]

K = 0.000000

A = 0.417491E-08 Β = 0.514111E-13

C = -0.666592E-18

D = 0.141913E-22

[Surface number 20] κ == 0.000000 Α = 0.166854E-07

Β = 0.370389E-12

C = -0.138273E-16

D = -0.304113E-20

[Surface number 24]

K = 0.000000

A = 0.361963E-07

Β = -0.679214E-12

C = -0.128267E-16

D = 0.908964E-21 E = -0.121007E-25

[Surface number 40] K = 0.000000

A =-0.179608E-07

B = 0.149941E-12

C = -0.128914E-17

D = -0.506694E-21

E = 0.204017E-25

F = -0.730011E-30 In this embodiment, the azimuth angles (rotation angles around the optical axis) of the lens components LP11 to LP15 made of fluorite in the optical members constituting the projection optical system are adjusted. This corrects the adverse effect (polarization aberration) due to birefringence.

FIG. 22A shows the points of the lens components LP11 to LP15 made of fluorite on the optical axis when the crystal axis [1 1 1] of fluorite matches the optical axis and their azimuths are aligned in the same direction. 4 shows an image intensity distribution. In FIG. 22A, the maximum value of PSF is 90.72.

Fig. 22B shows that the azimuth of the lens component LP14 of the fluorite lens components LP11 to LP15 is rotated by 180 ° around the optical axis with respect to the other fluorite lens components LP11 to LP13 and LP15. 7 shows a point image intensity distribution on the optical axis in the case of the above. In FIG. 22B, the maximum value of PSF is 96.41.

Referring to FIGS. 22A and 22B, the lens components LP11 to fluorite

When the azimuth angles of the crystal axes of LP15 are all the same (in the case of Fig. 22A), the scalar aberration 30 component is large and the PSF value is as low as 90.6, whereas the azimuth of the lens component LP14 Horn, other stone lens components; LP11 ~! Rotated 180 ° around the optical axis with respect to ^ 13,1 ^ 15 (When the relative azimuth between lens component LP14 and fluorite lens components LP11-LP13, LP15 is 60 ° In the case of Fig. 22B), the 3Θ component of the scalar aberration becomes smaller, 3 value also up to about 96.4 To Thus, by changing the azimuth of the crystal axis of the equiaxed crystal material, the optical performance of the projection optical system can be improved.

Fig. 22C shows the state of Fig. 22B (in which the azimuth of the lens component LP14 is rotated by 180 ° relative to the other fluorite lens components LP11 to LP13 and LP15 around the optical axis). Of the lens components LS1 to LS17 made of quartz in the projection optical system, the lens components LS12 and LS14 near the pupil are given a birefringence distribution for correcting the aberration shown in Fig. 22B. . As a result, the maximum value of the PSF value becomes 99.86, and the optical performance of the projection optical system can be further improved.

By the way, in the examples shown in FIGS. 22A to 22C, a method was used in which the crystal axis [1 1 1] of the fluorite lens component in the projection optical system was made to coincide with the optical axis. And the optical axis may be matched.

Fig. 23A shows a lens component LP11 to LP15 made of fluorite, as in Fig. 22A, when the crystal axis [1 1 1] of fluorite matches the optical axis, and the azimuths are aligned in the same direction. 5 shows a point image intensity distribution on the optical axis at. FIG. 23B shows that, among the fluorite lens components LP11-LP15, the optical axes of the lens components LP11, LP12 and LP13 coincide with the crystal axis [100] of the fluorite, and the optical axes of the lens components LP14 and LP15. The fluorite crystal axis

This is an example of matching with [1 1 0].

Then, in the lens components LP11, LP12, and LP13 having the crystal axis [100] as the optical axis, the azimuths of the lens components LP11 and LP13 around the optical axis are aligned, and the azimuth of the lens component LP12 is changed to the lens component LP11. And it is rotated around the optical axis by 45 ° with respect to LP13. Also, in the lens components LP14 and LP15 having the crystal axis [110] as the optical axis, the azimuth of one lens component is set to be 90 ° around the optical axis with respect to the azimuth of one lens component. Rotating.

Referring to FIG. 23A and FIG. 23B as comparative examples, in the case of FIG. 23B, the maximum value of the PSF value is 99.4, and it can be seen that the optical system has good optical performance. Note that in Figure 23B, in order to capture the slightly remaining polarization aberration component, As in the case of 22C, at least one of the lens components LS1 to LS17 made of quartz is given a predetermined birefringence distribution to further improve the optical performance.

FIG. 24 is a diagram showing a lens configuration of a projection optical system according to Example 2 of the present invention. The projection optical system of this embodiment uses quartz SiO ₂ and fluorite C a F ₂ as optical materials, and an image of the reticle R arranged on the first surface is arranged on the second surface. Project on W. The projection optical system of the second embodiment includes lenses LP11 to LP16 formed of fluorite and having a positive refractive power, and lenses LS1 to LS16 formed of quartz. The reference wavelength of the projection optical system of the second embodiment is 193.3 nm (ArF excimer laser), which is a double-sided telecentric optical system.

Table 3 below shows the specification values of the projection optical system according to the second example. The meanings of the symbols in Table 3 are the same as those in Table 1, and the description is omitted here.

Table 4 shows the aspheric coefficient for each aspheric surface. The aspherical shape is represented by the above-described equation (10). In Table 4, Era described in the column of each aspheric coefficient represents ΙΟια.

Here, mm can be used as an example of the unit of the radius of curvature and the surface interval in the specification values of the present embodiment. The refractive index of each glass material at the wavelength of 193.3 nm is as shown in the first embodiment.

[Table 3]

β = — 0.25

ΝΑ = 0.85

Β = 23.4

Surface number Curvature radius Surface spacing Glass material

1 -1664 .993 14.681 S i 0 ₂

2 200.000 38.160

3 -97.636 39.394 S i 0 ₂ o

〇〇

〇 0 〇〇〇 0

o ω of ω ϋ

〇 ί

CM o o

CO m

σι o r-

[

ro LO

LO LO LO

cm

69

[9 τ · ^ deer]

^ ζ-30805Δ £ · 2- = Ή

02-309T05 £ '2 = α

9T-a0T £ T58'2- = O

-3〇6 06'ς = e

Δ0-ϋ06009 ^ τ- = ν 02 ΟΟΟΟΟΟΌ = ¾

[S each 銎 ffl]

[挲]

009 οτ oo V 91 866 * ε L69 '^ T05- ε

τε9 "90 2

d Β〇 8 9 τ

οοο'τ TLL'9 £ Z

οοο * τ 296 "9 n 8ε

: ο ΐ S 8 ε "68τ L £

οοο'τ 691 * 655- 9 £

: ο ΐ S 088 · £ 60 * £ 901 ςε

£ 9L'9Z οοο * οοε- ε

ϊ S 990 Ή οβνττζ- εε

fL9 'T ££-

Ό ΐ S 086 * £ 9 / .τε

2S9 6Τ £ L '18L- οε

LlOLO / ZOdt / Ud St0L00 / £ 0 OAV K = 0.000000

A = 2.294100E-08

B = -2.794170E-13

C = 1.017110E-17 D = 5.514660E-22

E = -5.807000E-26

F = 4.364070E-30

[Surface number 2 2]

K = 0.000000

A = 7.961350E-09

B = -3.690120E-12

C = 1.927460E-17

D = 5.305600E-21

E = -2.919800E-26 F = -2.770450E-29

[Surface number 26]

= 0.000000

A = 2.103660

E-08B = -6.466850E-13 C = -6.551390E-18

D = 2.426880E-22

E = 1.189120E-27

F = -3.538550E-31

[Surface number 40]

K = 0.000000

A 1.693250E-08 B = 6.620660E-13

C = -9.551420E-18

D = -l .367360E-21

E = 1.080030E-25

F = -4.115960E-30

By the way, in this embodiment, by adjusting the azimuth angle (rotation angle around the optical axis) of the lens components LP11 to LP16 made of fluorite in the optical members constituting the projection optical system, the adverse effect due to birefringence ( (Polarization aberration) is corrected.

FIG. 25A shows the point image intensity distribution on the optical axis when the influence of the intrinsic birefringence of fluorite is neglected for comparison. In FIG. 25A, the maximum value of PSF is 99.97.

Fig. 25B shows a point image of the lens components LP11 to LP16 made of fluorite on the optical axis when the crystal axis [111] of the fluorite matches the optical axis and their azimuths are aligned in the same direction. 3 shows an intensity distribution. In FIG. 25A, the maximum value of PSF is 94.57.

Fig.25C shows the azimuth of the lens component LP11 of the fluorite lens components LP11 to LP16, which is rotated by 60 ° around the optical axis relative to the other fluorite lens components LP12 to LP14 and LP16. The point image intensity distribution on the optical axis when the azimuth of the lens component LP15 is rotated by 60 ° relative to the other fluorites: LP12 to LP14 and LP16 around the optical axis is shown. In Fig. 25C, the maximum number of PSF is 95.86.

Referring to FIGS. 25B and 25C, when the azimuthal angles of the crystal axes of the lens components LP11 to LP16 made of fluorite are all the same (in the case of FIG. 25B), the 30 component of the scalar aberration is large. , And the PSF value is as low as about 94.6, but the azimuth of the lens component LP11 is rotated by 60 ° relatively around the optical axis with respect to the other stone lens components LP12 to LP14, LP16. , And lens component LP15 azimuth angle to other fluorite lens components

When rotated around the optical axis by 60 ° relative to LP12 to LP14 and LP16 (Fig. 25 In the case of C), the 30 component of the scalar aberration becomes small, The three values also rise to about 95.8. As described above, by changing the azimuth of the crystal axis of the equiaxed crystal material, the optical performance of the projection optical system can be improved.

Fig. 25D shows the state of Fig. 25C (in which the azimuths of lens components LP11 and LP15 are rotated by 60 ° around the optical axis relative to the other fluorite lens components LP12 to LP14 and LP16). Of the lens components LS1 to LS16 made of quartz in the projection optical system, the lens component LSI4 near the pupil is provided with a birefringence distribution for correcting the aberration shown in FIG. 25C. As a result, the maximum value of the PSF value becomes 99.82. Here, comparing with the ideal state of Fig. 25A, the maximum value of PSF in Fig. 25A is 99.92, while in Fig. 25D, the maximum value of PSF is improved to almost the same value. It is clear that the optical performance of the projection optical system can be further improved. By the way, in the examples shown in FIGS. 25A to 25D, the method in which the crystal axis [1 1 1] of the fluorite lens component in the projection optical system is made to coincide with the optical axis is used. Similar to the embodiment, another crystal axis may be coincident with the optical axis.

Figure 26A shows the lens component of the fluorite lens components LP11 to LP16 in the projection optical system.

The optical axes of LP11 and LP12 are aligned with the crystal axis of fluorite [1 10], the optical axes of lens components LP 13 and LP14 are aligned with the crystal axis of fluorite [100], and the lens components LP15 and LP16 are aligned. Fig. 3 shows a point image intensity distribution when the optical axis is matched with the crystal axis [1 1 1] of fluorite. In the case of FIG. 26A, in the lens components LP11 and LP12 having the crystal axis [1 110] as the optical axis, the azimuth of one lens component is shifted by 90 ° with respect to the azimuth of one lens component. Rotating around. In the lens components LP 13 and LP 14 having the crystal axis “100” as the optical axis, the azimuth of one lens component is rotated around the optical axis by 45 ° with respect to the azimuth of one lens component. In the lens components LP15 and LP16 having the crystal axis [1 1 1] as the optical axis, the azimuth of one lens component is rotated around the optical axis by 60 ° with respect to the azimuth of the other lens component. Let me know. Referring to FIGS. 25B and 26A as comparative examples, in the case of FIG. 26A, it can be seen that the maximum value of the PSF value is 98.76, and that it has good optical performance. . Further, FIG. 26B shows, in addition to the state of FIG. 26A, a lens component LS I〜 made of quartz in the projection optical system. This is a point image intensity distribution on the optical axis when a birefringence distribution for correcting the difference represented by is given. As a result, the maximum value of the PSF value is 99.776. Here, when compared with the ideal state of Fig. 25A, the maximum value of PSF in Fig. 25A is 99.92, while in Fig. 25D, the maximum value of PSF is almost equal. It is clear that the optical performance of the projection optical system has been further improved.

In the exposure apparatus of each of the above-described embodiments, the reticle (mask) is illuminated by the illumination device (illumination step), and the transfer pattern formed on the mask is exposed on the photosensitive substrate using the projection optical system (exposure step). Thus, microdevices (semiconductor elements, imaging elements, liquid crystal display elements, thin-film magnetic heads, etc.) can be manufactured. The flowchart of FIG. 27 shows an example of a method for obtaining a semiconductor device as a micro device by forming a predetermined circuit pattern on a wafer or the like as a photosensitive substrate using the exposure apparatus of each embodiment. It will be described with reference to FIG.

First, in step 301 of FIG. 27, a metal film is deposited on one lot of wafers. In the next step 302, a photoresist is applied on the metal film on the wafer of the lot. Thereafter, in step 303, the image of the pattern on the mask is sequentially exposed and transferred to each shot area on the one-lot wafer via the projection optical system using the exposure apparatus of each embodiment. . Then, in step 304, the photoresist on the one lot of wafers is developed, and then in step 304, etching is performed on the one lot of wafers using the resist pattern as a mask. Thus, a circuit pattern force S corresponding to the pattern on the mask is formed in each shot area on each wafer.

After that, the circuit pattern of the upper layer is formed, etc. Devices such as elements are manufactured. According to the above-described semiconductor device manufacturing method, a semiconductor device having an extremely fine circuit pattern can be obtained with high throughput. In steps 301 to 305, a metal is vapor-deposited on the wafer, a resist is applied on the metal film, and the respective steps of exposure, development, and etching are performed. It is needless to say that a silicon oxide film may be formed on the wafer, a resist may be applied on the silicon oxide film, and each process such as exposure, development, and etching may be performed.

In the exposure apparatus of each embodiment, a liquid crystal display element as a micro device can be obtained by forming a predetermined pattern (circuit pattern, electrode pattern, etc.) on a plate (glass substrate). Hereinafter, an example of the technique at this time will be described with reference to the flowchart in FIG. In FIG. 28, in a pattern forming step 401, a so-called optical lithography is used in which a mask pattern is transferred and exposed to a photosensitive substrate (a glass substrate coated with a resist or the like) using the exposure apparatus of each embodiment. The process is executed. By this photolithography process, a predetermined pattern including a large number of electrodes and the like is formed on the photosensitive substrate. Thereafter, the exposed substrate undergoes each of a developing process, an etching process, a reticle peeling process, and the like, whereby a predetermined pattern is formed on the substrate, and the process proceeds to a next color filter forming process 402.

Next, in the color filter forming step 402, a large number of sets of three dots corresponding to R (Red), G (Green), and B (Blue) are arranged in a matrix, or R, G, B A color filter in which a set of three stripe filters is arranged in a plurality of horizontal scanning line directions is formed. Then, after the color filter forming step 402, a cell assembling step 403 is performed. In the cell assembling step 403, a liquid crystal panel (liquid crystal cell) is formed by using the substrate having the predetermined pattern obtained in the pattern forming step 401 and the color filter obtained in the color filter forming step 402. Assemble the. In the cell assembling step 403, for example, the substrate having the predetermined pattern obtained in the pattern forming step 401 and the color filter forming layer are formed. Liquid crystal is injected between the color filter obtained in step 402 and the liquid crystal panel (liquid crystal cell).

Then, in a module assembling step 404, components such as an electric circuit and a backlight for performing a display operation of the assembled liquid crystal panel (liquid crystal cell) are attached to complete a liquid crystal display element. According to the above-described method for manufacturing a liquid crystal display element, a liquid crystal display element having an extremely fine circuit pattern can be obtained with high throughput.

Industrial applicability

As described above, according to the present invention, even when a crystalline material exhibiting intrinsic birefringence such as fluorite is used, it is possible to secure good optical performance without being substantially affected by birefringence. An optical system can be manufactured.

Claims

The scope of the claims

1. A projection optical system that forms an image of a first surface on a second surface based on light of a predetermined wavelength, wherein the projection optical system has at least one equiaxed crystal system that is transparent to the light of the predetermined wavelength. In a method for manufacturing a projection optical system including a refraction member made of a crystalline material,

While evaluating the first polarized light component and the light of the second polarized light component different from the first polarized light component, the orientation of the crystal axis of the refraction member made of the at least one equiaxed crystal material is determined. A design step of obtaining predetermined design data including an auxiliary step of determining; a crystal material preparing step of preparing the equiaxed crystal material; and a crystal axis measurement of measuring a crystal axis of the equiaxed crystal material. A refraction member forming step of forming a refraction member having a predetermined shape from the equiaxed crystal material based on the design data in the design step; and a crystal of the refraction member obtained in the design step. And assembling the refraction member on the basis of the axial direction.

2. The method further includes providing at least one refraction member having a predetermined birefringence distribution,

2. The method according to claim 1, wherein the predetermined birefringence distribution is determined according to the design data in the design step.

3. The predetermined birefringence distribution is at least one of a predetermined stress birefringence distribution of the refraction member and a birefringence distribution caused by a thin film provided on the refraction member. 3. The method for manufacturing a projection optical system according to item 2 above.

4. The method for manufacturing a projection optical system according to claim 2, wherein the refraction member having the predetermined birefringence distribution is made of quartz or quartz in which fluorine is doped.

5. The effective diameter of the refractive member having the stress birefringence distribution is ψc,

A light beam emitted from a predetermined point on one surface passes through the refractive member having the stress birefringence distribution. When the luminous flux diameter when passing is ΦP,

6. The method of manufacturing a projection optical system according to claim 2, wherein 0.6 <φρ / φc ≦ 1 is satisfied.

6. The method further includes an aspheric surface forming step of forming a surface shape of at least one optical member in the projection optical system into an aspheric shape.

The method according to any one of claims 1 to 5, wherein the aspherical shape is determined according to design data in the design step.

7. The method according to claim 6, wherein the aspherical shape has an aspherical shape that is asymmetrical with respect to an optical axis of the optical member.

8. The assembling step includes:

An optical performance measurement assisting step of measuring the optical performance of the assembled projection optical system; and a position and / or a position of at least one optical member in the projection optical system in order to make the measured optical performance a predetermined optical performance. Or an optical member adjustment assisting step of changing the posture; and an aspheric surface for forming the surface shape of at least one optical member in the projection optical system into an aspherical shape in order to make the measured optical performance a predetermined optical performance. The method for manufacturing a projection optical system according to any one of claims 1 to 7, further comprising:

9. The method for manufacturing a projection optical system according to claim 8, wherein the aspherical shape is determined in consideration of design data in the design process.

10. The assembling step includes:

The projection according to any one of claims 1 to 9, further comprising an azimuth angle adjusting and trapping step of adjusting an azimuth angle of the refraction member made of the equiaxed crystal system around the optical axis. Optical system manufacturing method.

1 1. The assembling step is

A polarization optical performance measurement assisting step of measuring the optical performance of the assembled projection optical system with respect to light of a plurality of polarization components, The azimuth angle adjustment assisting step is performed based on the measured optical performance of the plurality of polarization components so that the optical performance of the plurality of polarization components has a predetermined value. The method for manufacturing a projection optical system according to claim 10, wherein the azimuth angle is adjusted.

1 2. The assembling step includes:

Including an optical performance measurement assisting step of measuring the optical performance of the assembled projection optical system,

The azimuth angle adjustment assisting step adjusts the azimuth angle of the refraction member made of the equiaxed crystal system based on the measured optical performance so that the optical performance of the projection optical system becomes a predetermined value. 10. The method for manufacturing a projection optical system according to claim 10, wherein:

13. The production of the projection optical system according to any one of claims 1 to 12, wherein the equiaxed crystal material has calcium fluoride or barium fluoride. Method.

14. The method for manufacturing a projection optical system according to any one of claims 1 to 13, wherein the predetermined wavelength is a wavelength of 200 nm or less.

15. A projection optical system that forms an image of the first surface on the second surface based on light of a predetermined wavelength, wherein at least one equiaxed crystal that is transparent to the light of the predetermined wavelength. In a method of manufacturing a projection optical system including a refraction member made of a system crystal material,

A step of replacing at least one of the refraction members in the projection optical system with another refraction member having a birefringence amount and Ζ or a birefringence distribution different from the refraction member. A method for manufacturing a projection optical system.

16. The manufacturing method according to claim 15, wherein said another refraction member comprises an equiaxed crystalline material or an amorphous material.

17. Projection light that forms an image of the first surface on the second surface based on light of a predetermined wavelength A method of manufacturing a projection optical system, comprising: a refraction member made of at least one equiaxed crystal material having transparency to light having the predetermined wavelength.

A method of manufacturing a projection optical system, comprising: adjusting a position, a Z, or a posture of an optical member having a predetermined birefringence distribution in the projection optical system to correct polarization aberration.

18. The manufacturing method according to claim 17, wherein the polarization aberration includes rotationally asymmetric polarization aberration.

19. A projection optical system manufactured according to the manufacturing method according to any one of claims 1 to 18.

20. In a projection optical system that forms an image of the first surface on the second surface based on light of a predetermined wavelength,

An equiaxed refraction member made of at least one equiaxed crystal material having transparency to the light having the predetermined wavelength; and deterioration of optical performance due to intrinsic birefringence of the equiaxed refraction member. And a non-crystalline refraction member made of a non-crystalline material for compensating the following.

21. The equiaxed refraction member has a crystal axis [100] or a crystal axis optically equivalent to the crystal axis [100], and an optical axis of the equiaxed refraction member. 17. The projection optical system according to claim 16, wherein the projection optical system is formed so as to substantially match.

22. The equiaxed refraction member made of the equiaxed crystal material includes a plurality of equiaxed refraction members,

17. The method according to claim 16, wherein the crystal axis directions of the plurality of equiaxed refraction members are determined so as to reduce deterioration of optical performance due to the intrinsic birefringence. Projection optics.

2 3. The maximum value of the angle with respect to the optical axis of the light beam passing through the equiaxed refraction member, in which the crystal axis orientation is determined so as to reduce the deterioration of the optical performance due to the intrinsic birefringence, is: 19. The projection optical system according to claim 18, wherein the angle is larger than 20 degrees.

24. The equiaxed refraction member, in which the crystal axis orientation is determined so as to reduce the deterioration of the optical performance due to the intrinsic birefringence, is provided at the pupil position on the second surface side of the projection optical system, 10. The projection optical system according to claim 18, wherein the projection optical system is disposed between the first surface and the second surface.

2 5. The plurality of equiaxed refraction members include:

A first group of light transmitting members formed so that the crystal axis [100] or a crystal axis optically equivalent to the crystal axis [100] and the optical axis substantially coincide with each other;

A second group of light transmitting members formed so that the crystal axis [100] or a crystal axis optically equivalent to the crystal axis [100] and the optical axis substantially coincide with each other,

The first group of light transmitting members and the second group of light transmitting members have a positional relationship relatively rotated by about 45 ° about an optical axis. 21. The projection optical system according to any one of items 8 to 20.

2 6. The plurality of equiaxed refraction members are:

A third group of light transmitting members formed such that the crystal axis and the optical axis thereof are substantially the same as the crystal axis [1 1 1] or the crystal axis [1 1 1];

A fourth group of light transmitting members formed so that the crystal axis [1 1 1] or the crystal axis optically equivalent to the crystal axis [1 1 1] and the optical axis substantially coincide with each other,

The light transmitting member of the third group and the light transmitting member of the fourth group have a positional relationship relatively rotated about 60 ° about an optical axis. 18. The projection optical system according to any one of items 18 to 21.

2 7. The plurality of equiaxed refraction members include:

A crystal axis [1 10] or a crystal axis optically equivalent to the crystal axis [1 10] A fifth group of light transmitting members formed so that their optical axes substantially coincide with each other; and a crystal axis [1 110] or a crystal axis optically equivalent to the crystal axis [1 110] and an optical axis. A sixth group of light transmitting members formed so as to substantially coincide with each other,

The light transmitting member of the fifth group and the light transmitting member of the sixth group have a positional relationship relatively rotated by about 90 ° about an optical axis. The projection optical system according to any one of Items 8 to 22.

2 8. The plurality of equiaxed refraction members are:

A fifth group of light transmitting members formed so that the crystal axis [1 110] or the crystal axis optically equivalent to the crystal axis [1 110] and the optical axis substantially coincide with each other. The projection optical system according to any one of claims 18 to 20, wherein: .

2 9. The plurality of equiaxed refraction members are:

A third group of light transmitting members formed so that the crystal axis [1 1 1] or the crystal axis optically equivalent to the crystal axis [1 1 1] substantially coincides with the optical axis. 25. The projection optical system according to claim 24, wherein:

30. In the plurality of equiaxed refraction members in which the crystal axis orientation is determined so as to reduce the deterioration of the optical performance due to the intrinsic birefringence, a predetermined crystal axis substantially coincides with an optical axis. A seventh group of light transmitting members formed as described above, and an eighth group of light transmitting members formed so that a predetermined crystal axis and an optical axis substantially coincide with each other,

The glass path length when a light ray corresponding to the maximum numerical aperture of the projection optical system passes through the light transmitting member of the seventh group is L7, and a light ray corresponding to the maximum numerical aperture of the projection optical system is the eighth. When the glass path length when passing through the light transmitting member of the group is L 8 and the predetermined wavelength is 1,

Claim 1 characterized by satisfying ^IL7-L8I / 2 < ^{3X10 + 5} .

26. The projection optical system according to any one of items 8 to 25.

31. The method according to claim 26, wherein the maximum value of the angle of the light beam passing through the light transmitting members of the seventh group and the eighth group with respect to the optical axis exceeds 20 degrees. 3. The projection optical system according to 1.

32. The seventh group and the eighth group of light transmitting members are arranged between the pupil position on the second surface side of the projection optical system and the second surface. The projection optical system according to claim 26 or 27.

33. The method according to any one of claims 16 to 28, further comprising an aspherical surface for reducing a scalar component in deterioration of optical performance due to the intrinsic birefringence. Projection optics.

34. The projection according to claim 29, wherein the aspherical surface has a shape that is rotationally asymmetric with respect to the optical axis of the refraction member provided with the aspherical surface. Optical system.

35. The projection optical system according to any one of claims 16 to 30, wherein the amorphous refraction member has a stress birefringence distribution.

36. The stress birefringence distribution according to claim 3, wherein the stress birefringence distribution is generated due to at least one of an impurity and a density distribution due to a heat history at the time of manufacturing the amorphous refraction member. 2. The projection optical system according to item 1.

37. The projection optical system according to any one of claims 16 to 32, wherein the amorphous optical member is quartz or quartz doped with fluorine.

38. The method for manufacturing a projection optical system according to any one of claims 16 to 33, wherein the equiaxed refraction member has calcium fluoride or barium fluoride. .

39. In a projection optical system that forms an image of the first surface on the second surface based on light of a predetermined wavelength,

A twin refraction member made of a twin having transparency to the light having the predetermined wavelength. A projection optical system, comprising:

40. The twin boundary or twin plane of the twin refraction member is set so as to reduce deterioration of optical performance due to intrinsic birefringence of the twin. Item 6. The projection optical system according to Item 5.

41. The projection optical system according to any one of claims 16 to 36, wherein the predetermined wavelength is a wavelength equal to or less than 200ηια.

42. A projection exposure apparatus for projecting and exposing an image of a projection original placed on a first surface to a workpiece placed on a second surface based on light of a predetermined wavelength,

A light source for supplying light of the predetermined wavelength;

An illumination optical system arranged in an optical path between the light source and the first surface, for guiding the light from the light source to the projection master; and an optical path between the first surface and the second surface. The projection optical system according to any one of claims 15 to 37, wherein the projection optical system is configured to form an image of the projection original on the second surface. Dew

4 3. A projection exposure method for projecting and exposing an image of a projection original arranged on a first surface to a workpiece arranged on a second surface based on light of a predetermined wavelength,

A step of supplying the light of the predetermined wavelength; a step of illuminating the projection master using the light of the predetermined wavelength; and a step based on the illuminated light from the projection master. 39. A projection exposure method, comprising: forming an image of the projection original on the second surface by the projection optical system according to any one of items 5 to 37.

44. Applied to a projection exposure apparatus for projecting and exposing an image of a projection original plate arranged on a first surface to a work piece arranged on a second surface based on light of a predetermined wavelength, A method for manufacturing an illumination optical system including a refraction member made of at least one equiaxed crystal material having transparency with respect to

In order to correct the polarization aberration, the crystal refraction made of the equiaxed crystal material A manufacturing method comprising a step of optimizing a crystal axis orientation of a member.

45. The manufacturing method according to claim 44, further comprising a step of preparing an amorphous refraction member made of an amorphous material for correcting the remaining polarization aberration.

46. A projection exposure apparatus for projecting and exposing an image of a projection original placed on a first surface to a work piece placed on a second surface based on a predetermined wavelength,

A light source for supplying light of the predetermined wavelength;

The illumination optical system according to claim 44 or 45, disposed between the light source and the first surface, for guiding the light from the light source to the projection original;

A projection optical system that is arranged in an optical path between the first surface and the second surface and forms an image of the original projection plate on the second surface;

A projection exposure apparatus comprising:

47. A projection exposure method for projecting and exposing an image of a projection original placed on a first surface to a work piece placed on a second surface based on a predetermined wavelength,

Supplying the light having the predetermined wavelength; and illuminating the projection original plate with the light having the predetermined wavelength via the illumination optical system according to claim 44.

Forming an image of the projection master on the second surface based on the illuminated light from the projection master;

A projection exposure method comprising: