WO2006085524A1

WO2006085524A1 - Exposure equipment

Info

Publication number: WO2006085524A1
Application number: PCT/JP2006/302052
Authority: WO
Inventors: Toshimasa Shimoda
Original assignee: Nikon Corporation
Priority date: 2005-02-14
Filing date: 2006-02-07
Publication date: 2006-08-17
Also published as: TW200633011A

Abstract

Exposure equipment for lithography of a semiconductor integrated circuit and the like is provided for maintaining relative positions of a lighting optical system and a projection optical system at a high accuracy. The exposure equipment is provided with the lighting optical system for irradiating a reticle with illuminating light and the projection optical system for projecting the illuminating light from the reticle on a sensitive substrate. The exposure equipment is characterized in that a part of the lighting optical system and the projection optical system are arranged in a space formed between a plane including the reticle surface and a plane including the sensitive substrate surface, and the lighting optical system and the projection optical system are supported on a same mount. Furthermore, the equipment is characterized in that the mount is supported in a chamber through a vibration eliminating apparatus, and a reticle side interferometer for measuring the positions of the projection optical system and a reticle stage is firmly fixed on the mount.

Description

Exposure equipment

Technical field

The present invention relates to an exposure apparatus used for lithography such as a semiconductor integrated circuit.

Background art

In recent years, with the miniaturization of semiconductor integrated circuits, EUV exposure apparatuses using EUV light having a wavelength of about 13 nm have been developed in order to improve the resolving power of optical systems limited by the diffraction limit of light. Yes. In such an EUV light exposure apparatus, the illumination optical system using a mirror irradiates the reticle with illumination light, and the illumination light reflected by the reticle is projected onto the sensitive substrate by the projection optical system using the mirror. High accuracy is required due to the relative positional accuracy between the projector and the projection optical system.

Patent Document 1: Japanese Patent No. 3200282

Disclosure of the invention

Problems to be solved by the invention

[0003] However, in the conventional exposure apparatus, the illumination optical system and the projection optical system are supported on separate platforms, and the illumination optical system and the projection optical system are independently displaced. It is difficult to maintain the relative position between the projector and the projection optical system with high accuracy!

The present invention has been made in order to solve the conventional problems, and it is an object of the present invention to provide an exposure apparatus capable of maintaining the relative position between the illumination optical system and the projection optical system with high accuracy. .

Means for solving the problem

An exposure apparatus according to claim 1 is an exposure apparatus comprising: an illumination optical system that irradiates illumination light onto a reticle; and a projection optical system that projects illumination light having the reticle power onto a sensitive substrate. A part of the illumination optical system and the projection optical system are arranged in a space formed between the surface including the sensitive substrate surface and the surface including the sensitive substrate surface, and the illumination optical system and the projection optical system are the same. It is characterized by being supported by a gantry. [0005] An exposure apparatus according to a second aspect is the exposure apparatus according to the first aspect, wherein the gantry is supported in a chamber via a vibration isolation device.

The exposure apparatus according to claim 3 is the exposure apparatus according to claim 1 or 2, wherein a reticle-side interferometer that measures the positions of the projection optical system and the reticle stage is fixed to the gantry. To do.

[0006] The exposure apparatus according to claim 4 is the exposure apparatus according to claim 1, wherein the position of the projection optical system and the sensitive substrate stage is measured on the gantry. The sensitive substrate side interferometer is fixed.

The exposure apparatus according to claim 5 is the exposure apparatus according to claim 1, wherein the position of the sensitive substrate in the optical axis direction of the projection optical system is measured on the gantry. It is characterized by fixing an autofocus device.

[0007] An exposure apparatus according to claim 6 is the exposure apparatus according to claim 1, wherein the reticle side reference microscope for measuring a planar position of the reticle is mounted on the gantry. It is characterized by being fixed.

The exposure apparatus according to claim 7 is the exposure apparatus according to claim 1, and the exposure apparatus according to claim 6, wherein a sensitive substrate side reference microscope for measuring a planar position of the sensitive substrate is provided on the mount. It is characterized by being fixed.

The invention's effect

In the exposure apparatus of the present invention, since the illumination optical system and the projection optical system are supported on the same frame, the relative position between the illumination optical system and the projection optical system can be maintained with high accuracy. wear.

Brief Description of Drawings

FIG. 1 is an explanatory diagram viewed from the side of an embodiment of an exposure apparatus of the present invention.

2 is an explanatory view of the exposure apparatus of FIG. 1 as viewed from the AA direction.

FIG. 3 is an explanatory view showing a measuring device arranged on the gantry of the exposure apparatus of FIG. 1.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1 and 2 schematically show an embodiment of the exposure apparatus of the present invention. This fruit In the embodiment, the present invention is applied to an EUV exposure apparatus using EUV light. This exposure apparatus has a base plate 11 at the bottom. The base plate 11 is held on the floor 15 via a vibration isolator 13. A chamber 17 is disposed on the base plate 11. The chamber 17 has a rectangular parallelepiped shape and has an upper surface portion 17a and a side surface portion 17b. The inside of the chamber 17 is evacuated by a vacuum pump (not shown) and kept in a vacuum.

A gantry 19 is horizontally disposed in the chamber 17. The gantry 19 is held in the chamber 17 via a vibration isolation device 21. As shown in FIG. 2, the vibration isolator 21 is arranged at three locations on the lower surface of the gantry 19. Each vibration isolator 21 is disposed between the frame 19 and the beams 19 a, 23 b, 23 c in which the side surface 17 b force of the chamber 17 extends inward.

In the present embodiment, the member that supports the force stand 19 supported by the beams 23a, 23b, and 23c via the vibration isolator 21 is not limited to the beams 23a, 23b, and 23c. For example, three or four legs (not shown) may be arranged on the base plate 11, and the mount 19 may be arranged on the legs via the vibration isolator 21. Alternatively, the legs can penetrate the base plate 11 and be installed directly on the floor 15!

An illumination optical system 25 and a projection optical system 27 are arranged on the gantry 19. The illumination optical system 25 includes a fly-eye mirror (not shown) that equalizes the illuminance of the EUV light source and a condenser mirror (not shown) that collects the EUV light that is uniformed by the fly-eye mirror. ) Is included. These mirrors are arranged in the upper part 25b of the illumination optical system 25. The illumination optical system 25 and the projection optical system 27 are arranged so as to penetrate the gantry 19 in the vertical direction and are fixed to the gantry 19. A lower portion 25 a of the illumination optical system 25 extends through the side surface portion 17 b of the chamber 17 and extends outside the chamber 17.

A wafer stage 29 is disposed below the projection optical system 27. The wafer stage 29 is arranged on the base plate 11 via the base member 31 !. A reticle stage 33 is disposed above the projection optical system 27. The reticle stage 33 is supported by a beam 35 projecting inward from the side surface portion 17b of the chamber 17.

Reticle side interferometer bases 37 and 39 are fixed on the upper surface of the gantry 19 so as to protrude toward the reticle stage 33. Reticle side interferometer pedestal 37 has a reticle stay as shown in Fig. 2. The interferometer base 39 on the reticle side is used for position measurement in the Υ direction. Further, wafer side interferometer bases 41 and 43 are fixed to the lower surface of the gantry 19 so as to protrude toward the wafer stage 29. As shown in FIG. 2, the wafer side interferometer base 41 is used for measuring the position of the wafer stage 29 in the vertical direction, and the wafer side interferometer base 43 is used for measuring the position in the X direction.

FIG. 3 schematically shows a measuring device arranged in the vicinity of the gantry 19 in this embodiment.

First and second reticle side interferometers 45 and 47 are arranged on a reticle side interferometer base 37 fixed to the upper surface of the gantry 19. The first reticle-side interferometer 45 reflects the laser beam on the length measuring mirror 49 fixed to the reticle stage 33 and measures the distance to the reticle stage 33 by the interference of the laser beam. Find the position coordinates. The second reticle-side interferometer 47 reflects the laser beam to the reference mirror 51 fixed to the projection optical system 27 and measures the distance to the projection optical system 27 by the interference of the laser beam. Then, by comparing the distance to the projection optical system 27 measured by the second reticle-side interferometer 47 with the distance to the reticle stage 33 measured by the first reticle-side interferometer 45, the projection optical system It is possible to know the position of the reticle stage 33 in the vertical direction with reference to 27. Note that the reticle side interferometer is also arranged on the reticle side interferometer base 39 for measuring the position in the X direction, and the measurement in the X direction is performed. However, since the configuration is the same, the detailed description is omitted.

First and second wafer side interferometers 53 and 55 are arranged on wafer side interferometer base 41 fixed to the lower surface of gantry 19. The first wafer side interferometer 53 reflects the laser beam on the length measuring mirror 57 fixed to the wafer stage 29, measures the distance to the wafer stage 29 by the interference of the laser beam, and moves the wafer stage 29 in the vertical direction. Find position coordinates. The second wafer side interferometer 55 reflects the laser beam to the reference mirror 59 fixed to the projection optical system 27 and measures the distance to the projection optical system 27 by the interference of the laser beam. Then, the distance to the projection optical system 27 measured by the second wafer side interferometer 55 is compared with the distance to the wafer stage 29 measured by the first wafer side interferometer 53. The position of the wafer stage 29 with reference to the projection optical system 27 can be known. X direction The wafer-side interferometer is also arranged on the wafer-side interferometer pedestal 43 for measuring the direction position, and measurement in the X direction is performed. However, since the configuration is the same, a detailed description is omitted.

[0016] Since the position of the reticle stage 33 relative to the projection optical system 27 can be known as described above, the positions of the reticle stage 33 and the wafer stage 29 relative to the projection optical system 27 are determined. I can know.

In this embodiment, the reticle-side reference microscope 61 of the offaxis system is fixed to the reticle-side interferometer base 37. The reticle 65 is aligned by detecting the reference mark of the reticle 65 attracted to the lower surface of the electrostatic chuck 63 of the reticle stage 33 by the reticle side reference microscope 61.

[0017] Further, an offaxis wafer-side reference microscope 67 is fixed to the wafer-side interferometer base 41. The wafer is aligned by detecting the alignment mark of the wafer 71 adsorbed on the upper surface of the electrostatic chuck 69 of the wafer stage 29 by the wafer side reference microscope 67.

Further, an autofocus (AF) device 73 for measuring the position of the upper surface of the wafer 71 in the optical axis direction is disposed on the lower surface of the gantry 19. The autofocus device 73 has a projection optical system 75 and a light receiving optical system 77. Detection of the position of the wafer 71 in the optical axis direction is performed by projecting a slit image from the projection optical system 75 onto the upper surface of the wafer 71 from an oblique direction and monitoring the position of the reflected slit by the light receiving optical system 77. . That is, when the wafer 71 moves in the optical axis direction of the projection optical system 27, the position of the slit incident on the light receiving optical system 77 varies due to the effect of oblique incidence. This variation is photoelectrically detected by the light receiving optical system 77 as a distance from the reference position.

In the above-described exposure apparatus, EUV light is generated by converting the target material into plasma in a light source unit (not shown) arranged outside the chamber 17. The generated EUV light is guided to the illumination optical system 25, reflected by a plurality of reflecting mirrors (not shown), and guided to the lower surface of a reticle (shown in FIG. 3) 65 disposed below the wafer stage 29. The reticle 65 has a multilayer film that reflects EUV light and an absorber pattern layer for forming a pattern. The EUV light is patterned by reflecting the EUV light on the reticle 65. The patterned EUV light is sequentially reflected by a plurality of mirrors (not shown) of the projection optical system 27, so that the reticle pattern is reflected. A reduced image of the turn is formed on Ueno 71 (shown in Figure 3). When exposing the die on the wafer 71, EUV light is irradiated onto a predetermined area of the reticle 65, and the reticle 65 and wafer 71 are compared with the projection optical system 27 according to a reduction ratio of the projection optical system 27. Move at speed. In this way, the reticle pattern is exposed to a predetermined exposure range (with respect to the die) on the wafer 71.

In the above-described exposure apparatus, the illumination optical system 25 and the projection optical system 27 are supported by the same mount 19, so that the relative positions of the illumination optical system 25 and the projection optical system 27 are maintained with high accuracy. Can have. That is, for example, when the gantry 19 is deformed by evacuating the chamber 17, the illumination optical system 25 and the projection optical system 27 are less likely to be independently displaced, and the illumination optical system 25 and the projection optical system 25 are projected. The relative position with the optical system 27 can be maintained with high accuracy. In addition, since the illumination optical system 25 and the projection optical system 27 are supported on the same base 19, the illumination optical system 25 and the projection optical system 27 are supported by the same base 19, compared with the case where the illumination optical system 25 and the projection optical system 27 are supported on separate bases 19. The relative position adjustment between the optical system 25 and the projection optical system 27 becomes easy, and the illumination optical system 25 and the projection optical system 27 can be easily arranged with high accuracy.

[0020] In the exposure apparatus described above, since the gantry 19 is supported by the chamber 17 via the vibration isolator 21, the floor 15, the wafer stage 29, and the vacuuming device (not shown) input via the chamber 17 It is possible to reliably block the vibration of the isotropic force, and the positional accuracy of the illumination optical system 25 and the projection optical system 27 can be stably maintained. In addition, the measurement accuracy of measurement devices such as reticle-side interferometers 45 and 47, wafer-side interferometers 53 and 55, reticle-side reference microscope 61, wafer-side reference microscope 67, and auto-focus device 73 placed on the pedestal 19 is improved. It can be maintained stably.

Furthermore, the first and second reticle side interferometers 45 and 47 are arranged on the reticle side interferometer base 37 on the upper surface of the gantry 19, and the first and second reticle side interferometer bases 41 on the lower surface of the gantry 19 are arranged. Since the second wafer side interferometers 53 and 55 are arranged, the positions of the reticle stage 33 and the wafer stage 29 relative to the projection optical system 27 can be measured with high accuracy.

Since the autofocus device 73 is fixed to the gantry 19 to which the projection optical system 27 is fixed, the relative position between the projection optical system 27 and the autofocus device 73 can be maintained with high accuracy. Position of wafer 71 in 27 optical axis directions with high accuracy Can be determined.

In addition, since the reticle side reference microscope 61 is fixed to the gantry 19 to which the projection optical system 27 is fixed, the relative position between the projection optical system 27 and the reticle side reference microscope 61 can be maintained with high accuracy. Thus, the planar position of the reticle 65 with respect to the projection optical system 27 can be measured with high accuracy.

Furthermore, since the wafer-side reference microscope 67 is fixed to the gantry 19 to which the projection optical system 27 is fixed, the relative positions of the projection optical system 27 and the wafer-side reference microscope 67 can be maintained with high accuracy, and projection can be performed. The plane position of the wafer 71 with respect to the optical system 27 can be measured with high accuracy.

(Supplementary items of the embodiment)

As mentioned above, the force which demonstrated this invention by embodiment mentioned above The technical scope of this invention is not limited to embodiment mentioned above.

For example, in the above-described embodiment, an example in which the present invention is applied to an exposure apparatus using EUV light has been described, but the present invention is widely applied to an exposure apparatus including an illumination optical system and a projection optical system. can do.

Claims

The scope of the claims

[1] An exposure apparatus comprising: an illumination optical system that irradiates illumination light onto a reticle; and a projection optical system that projects illumination light from the reticle onto a sensitive substrate.

Arranging a part of the illumination optical system and the projection optical system in a space formed between the surface including the reticle surface and the surface including the sensitive substrate surface,

An exposure apparatus characterized in that the illumination optical system and the projection optical system are supported on the same frame.

[2] In the exposure apparatus according to claim 1,

An exposure apparatus, wherein the gantry is supported in the chamber via a vibration isolation device.

[3] In the exposure apparatus according to claim 1 or claim 2,

An exposure apparatus, wherein a reticle-side interferometer for measuring positions of the projection optical system and a reticle stage is fixed to the gantry.

[4] In the exposure apparatus according to claim 1, the claim 1! And the claim 3 according to claim 1!

An exposure apparatus, wherein a sensitive substrate side interferometer for measuring the positions of the projection optical system and the sensitive substrate stage is fixed to the frame.

[5] In the exposure apparatus according to claim 1, the claim 1 !, and the claim 4 according to claim 1!

An exposure apparatus, wherein an autofocus device for measuring the position of the sensitive substrate in the optical axis direction of the projection optical system is fixed to the gantry.

[6] In the exposure apparatus according to claim 1, the claim 1 is!

An exposure apparatus, wherein a reticle-side reference microscope for measuring a planar position of the reticle is fixed to the frame.

[7] In the exposure apparatus according to claim 1, the claim 1 !, and the claim 6 according to claim 1!

An exposure apparatus, wherein a sensitive substrate side reference microscope for measuring a planar position of the sensitive substrate is fixed to the frame.