WO2011002881A1 - Polishing pad with array of gimballed abrasive segments - Google Patents

Abstract

An abrasive article with an array of independently gimballed abrasive members that are capable of selectively engaging with nanometer-scale and/or micrometer-scale asperities on the surfaces of substrates. Each abrasive member maintains a fluid bearing (air is the typical fluid) with the substrate. The spacing and pitch of the abrasive members can be adjusted to follow the topography of the substrate to remove a generally uniform layer of material, to engage with the peaks on the substrate to reduce the unevenness and/or to remove debris and contamination from the surface of the substrate.

Description

POLISHING PAD WITH ARRAY OF GIMBALLED ABRASIVE SEGMENTS

Cross-Reference to Related Applications

This application claims the benefit of the filing date of United States Provisional Patent Application Serial Number 61/221,554 filed June 30, 2009 and entitled "Abrasive Article with Array of Gimballed Abrasive Members and Method of Use", and of United States Provisional Patent Application Serial Number 61/248,194 filed October 2, 2009 and entitled "Method and Apparatus for Nano-Scale Cleaning", both of which are hereby incorporated herein in their entirety by reference.

Field of the Invention

The present application is directed to an abrasive article with an array of independently gimballed abrasive members that are capable of selectively engaging with nanometer-scale and/or micrometer-scale height variations and micrometer-scale and/or millimeter-scale wavelengths of waviness, on the surfaces of substrates. Each abrasive member maintains a fluid bearing with the substrate. The spacing and fly attitude of the abrasive members can be adjusted to follow the topography of the substrate to remove a generally uniform layer of material, to engage with the peaks on the substrate to remove target wavelengths of waviness, and/or to remove debris and contamination from the surface of the substrate. The abrasive members can include abrasive features, or can interact with free abrasive particles at an interface with the substrate, or a combination thereof.

Background of the Invention

Semiconductor wafers are typically fabricated using photolithography, which is adversely affected by inconsistencies or unevenness in the wafer surface. This sensitivity is accentuated with the current drive toward smaller, more highly integrated circuit designs. After each layer of the circuit is etched on the wafer, an oxide layer is put down as the base for the next layer. Each layer of the circuit can create roughness and waviness to the wafer that is preferably removed before depositing the next circuit layer. For many semiconductor applications the chemical mechanical processing ("CMP") is customized for each layer. A change in a single processing parameter, such as for example, pad design, slurry formulation, or pressure applied by the pad, can require the entire CMP process to be redesigned and recertified.

Figures 1 and 2 illustrate the shape of bits formed by etching, such as ion milling or reactive etching. Note that the tops of the bits are rounded, leading to head media spacing loss, roughness at the rounded areas, and magnetic damage due to etching of magnetic materials. Such bits are not viable for magnetic recording. The uneven material increases head media spacing and potential damage to the diamond-like-carbon overcoats. CMP processes have proven inadequate to achieving smooth and flat tops both before and after magnetic material deposition.

CMP is currently the primary approach to planarizing wafers, semiconductors, optical components, magnetic media for hard disk drives, and bit patterned or discrete track media (collectively "substrates"). CMP uses pads to press sub-micron sized particles suspended in the slurry against the surface of the substrate. The nature of the material removal varies with the hardness of the CMP pad. Soft CMP pads conform to the

nanotopography and tend to remove material generally uniformly from the entire surface. Hard CMP pads as shown in Figure 4 conform less to the nanotopography and therefore remove more material from the peaks or high spots on the surface and less material from low spots.

Traditionally, soft CMP pads have been used to remove a uniform surface layer as shown in Figure 3, such as removing a uniform oxide layer on a semiconductor device. Polishing a substrate with a soft pad also transfers various features from the polishing pad to the substrate. Roughness and waviness is typically caused by uneven pressure applied by the pad during the polishing process. The uneven pressure can be caused by the soft pad topography, the run out of the moving components, or the machined imperfections transferred to the pads. Run-out is the result of larger pressures at the edges of the substrate due to deformation of the soft pad. Soft pad polishing of heterogeneous layered materials, such as semiconductor devices, causes differential removal and damage to the electrical devices.

A CMP pad is generally of a polyurethane or other flexible organic polymer. The particular characteristics of the CMP pad such as hardness, porosity, and rigidity, must be taken into account when developing a particular CMP process for processing of a particular substrate. Unfortunately, wear, hardness, uneven distribution of abrasive particles, and other characteristics of the CMP pad may change over the course of a given CMP process. This is due in part to water absorption as the CMP pad takes up some of the aqueous slurry when encountered at the wafer surface during CMP. This sponge-like behavior of the CMP pad leads to alteration of CMP pad characteristics, notably at the surface of the CMP pad. Debris coming from the substrate and abrasive particles can also accumulate in the pad surface. This accumulation causes a "glazing" or hardening of the top of the pad, thus making the pad less able to hold the abrasive particles of the slurry and decreasing the pad's overall polishing performance. Further, with many pads the pores used to hold the slurry become clogged, and the overall asperity of the pad's polishing surface becomes depressed and matted.

Shortcomings of current CMP processes affect other aspects of substrate processing as well. The sub-micron particles used in CMP tend to agglomerate and strongly adhere to each other and to the substrate, resulting in nano-scale surface defects. Van der Waals forces create a very strong bond between these surface debris and the substrate. Once surface debris form on a substrate it is very difficult to effectively remove them using conventional cleaning methods. Various methods are known in the art for removing surface debris from substrates after CMP, such as disclosed in U.S. Pat. Nos. 4,980,536; 5,099,557; 5,024,968; 6,805,137 (Bailey); 5,849,135 (Selwyn); 7,469,443 (Liou); 6,092,253 (Moinpour et al); 6,334,229 (Moinpour et al); 6,875,086 (Golzarian et al); 7,185,384 (Sun et al); and U.S. Patent Publication Nos. 2004/0040575 (Tregub et al.); and 2005/0287032 (Tregub et al.), but have proven inadequate for the next generation semiconductors and magnetic media.

Current processing of substrates for semiconductor devices and magnetic media treats uniform surface layer reduction, planarization to remove waviness, and cleaning as three separate disciplines. The incremental improvements in each of these disciplines have not kept pace with the shrinking feature size of features demanded by the electronics industry.

Brief Summary of the Invention

The present application is directed to an abrasive article with an array of independently gimballed abrasive members that are capable of selectively engaging with nanometer-scale and/or micrometer-scale height variations and micrometer-scale and/or millimeter-scale wavelengths of waviness, on the surfaces of substrates. Each abrasive member maintains a fluid bearing with the substrate. The spacing, which includes clearance, pitch, and roll, of the abrasive members can be adjusted to follow the topography of the substrate to remove a generally uniform layer of material; to engage with the peaks on the substrate to remove target wavelengths of waviness; and/or to remove debris and contamination from the surface of the substrate.

The gimbals permit each abrasive member to move independently in at least pitch and roll relative to the substrate. The fluid bearing can be hydrodynamic, hydrostatic, or a combination thereof. The fluid can be gas, liquid, or a combination thereof. The present abrasive article can be used before or after features are formed on the substrates.

A hydrodynamic and/or hydrostatic bearing is used to provide vertical, pitch and roll stiffness to the abrasive member and to control the spacing and pressure distribution across the fluid bearing features on the abrasive members. Adjustments to certain variables, such as for example, the spacing (which includes minimal spacing and fly attitude of the abrasive members), pitch and roll stiffness which control fly attitude, the preload, and/or the abrasive features can be used to modify the cutting force applied to the substrate

Fluid bearing structures are fairly complex with a substantial number of variables involved in their design. The primary forces involved in a given fluid bearing are the gimbal structure and the preload. The gimbal structure applies both a pitch and roll moments to the individual abrasive members, and hence, the fluid bearing structures. If the gimbal is extremely stiff, the fluid bearing may not be able to form a pitch or roll angle. The preload and preload offset (location where the preload is applied) bias the fluid bearing toward the substrate. The preload is typically applied by a different structure than the gimbal structure.

Fluid bearing surface geometries play a large role in pressurization of the bearing. Possible geometries include tapers, steps, trenches, crowns, cross curves, twists, wall profile, and cavities. Finally, external factors such as viscosity of the bearing fluid and linear velocity play an extremely important role in pressurizing bearing structures.

The individual abrasive members are capable of selectively engaging with nanometer-scale and micrometer-scale height variations and/or micrometer-scale or millimeter-scale wavelengths of waviness on the surface of substrates to perform one or more of the following three overlapping and complementary functions: 1) following the topography of the substrate to remove a generally uniform layer of material; 2) engaging with the surface features such as peaks and valleys on the substrate to remove target wavelengths of waviness; and/or 3) removing debris and contamination from the surface of the substrate. Consequently, the present abrasive articles can be engineered to perform a wide variety of functions, including lapping, planarization, polishing, cleaning, and burnishing substrates. In connection with performing any of these three functions, the abrasive members may 1) include abrasive features positioned to interact with the substrate, 2) interact with free abrasive particles at the interface with the substrate, or 3) a combination thereof. Free abrasive particles can be used with either topography following or topography removing abrasive members.

While the abrasive features generally have a hardness greater than the substrate, this property is not required for every embodiment since any two solid materials that repeatedly rub against each other will tend to wear each other away. For example, relatively soft polymeric abrasive features molded on the abrasive members can be used to remove surface contaminants or can interact with free abrasive particles to remove material from the surface of a harder substrate. As used herein, "abrasive feature" refers to a portion of an abrasive member that comes in physical contact with a substrate or a contaminant on a substrate, independent of the relative hardness of the respective materials and the resulting cut rate.

Figure 5 is a schematic illustration of the topography present in any surface including very short wavelength known as roughness, micro-waviness in the range of 1 micron - lmm, and finally runnout in the range greater than a millimiter.

Figure 6 is a schematic illustration of a topography following abrasive member 1000 in accordance with an embodiment of the present invention. The abrasive member 1000 is typically designed to follow the topography by assuring that the trailing edge area has the largest pressure peak. For example, the fluid bearing can be pitched to ensure that the leading edge is spaced substantially higher above the substrate than the trailing edge. The trailing edge in contact with the substrate 1006 of the abrasive member 1000 applies a cutting force to nanometer-scale and/or micron-scale height variations 1008 on the surface 1004, while following the millimeter-scale and/or micrometer-scale wavelengths in the waviness on the substrate. Consequently, the abrasive member 1000 removes a generally uniform layer of material 1012 from peaks and valleys on the surface 1004, such as for example, removing or controlling the thickness of an oxide layer. As used herein,

"topography following" refers to an individually gimbaled abrasive member that generally follows millimeter-scale and/or micrometer-scale wavelengths of waviness on a substrate, while engaging with nanometer-scale height variations to primarily remove a generally uniform amount of material from the surface. The strategy described in Figure 6 is analogous to debris removal while maintaining a lower cutting force at the substrate while generating a large force to interact and remove asperities 1005.

Figure 7 is a schematic illustration of a topography removing abrasive member 1050 in accordance with an embodiment of the present invention. The leading edge 1056 and/or trailing edge 1058 of the abrasive member 1050 applies a cutting force to peaks 1060 of millimeter-scale and/or micrometer-scale wavelengths of the waviness 1062 on the surface 1054 of the substrate, while engaging with the valleys. Topography removal from original surface 1054 leads to a new surface 1012 substantially flatter. As used herein, "topography removing" refers to an individually gimbaled abrasive member that primarily removes nanometer-scale and/or micrometer-scale height variations from peaks and valleys of millimeter-scale and/or micrometer-scale wavelengths in the waviness on a substrate. Note that the abrasive removing member dimensions and pressure distribution dictates the peak and valley removal rate.

Figure 8 is a schematic illustration of a chemical mechanical polishing member 1100 in accordance with an embodiment of the present invention. The trailing edge 1106 of the abrasive member 1100 follows the millimeter-scale and/or micrometer-scale wavelengths in the waviness 1108 on the substrate, while interacting with free abrasives 1090. The abrasive member 1100 preferably is in contact at the trailing edge while the leading edge 1114 is free of contact with the substrate. The proposed chemical polishing strategy can be changed to render both leading and trailing edges in contact with the substrate while applying a force onto the free abrasives 1090 to promote material removal from the substrate 1004 to remove both the peaks and the valleys of the substrate surface. A similar strategy as shown in Figure 7 can also be adapted to remove the substrate topography of the substrate by designing the abrasive element to remove peaks of the substrate.

Various abrasive features are available for the present abrasive members, such as for example, a surface roughness formed on the leading and/or trailing edges of the abrasive members. That surface roughness may include a hard coat, such as for example, diamond-like-carbon. In another embodiment, the abrasive features may be discrete abrasive particles, such as for example, fixed diamonds. In yet another embodiment, the abrasive features may be structured abrasives, discussed further below.

For example, to remove all the wavelengths smaller than a desired value, the dimensions of the abrasive members can be greater than the target wavelengths. The wavelengths are determined by the gas pressure profile generated by the abrasive member and the size of the abrasive member. As a rule of thumb, the smallest circumferential wavelength is about one-fourth the length of the abrasive members.

The dimensions of the abrasive members and the pressure profile due to the hydrostatic and/or hydrodynamic lift (gas and/or liquid) determine the ability of the abrasive member to follow the waviness of the substrate. Assuming that the abrasive members can follow ¹A of its size, then all wavelengths smaller than the ¹A will cause interference with the abrasive members and material removal will ensue due to the interactions. Portions of the abrasive members generate a hydrodynamic lift causing predictable waviness following capability and stabilizing force countering the cutting forces.

Brief Description of the Several Views of the Drawing

Figure 1 is the configuration of a single bit on a bit patterned media for a hard disk drive.

Figure 2 is a perspective view of an array of bits on a bit patterned media.

Figure 3 is a schematic representation of a soft pad in contact with a wavy substrate

Figure 4 is a schematic representation of a hard pad in contact with a wavy substrate

Figure 5 is a schematic representation of the components describing a surface topography

Figure 6 is a schematic illustration of a debris removing abrasive member in accordance with an embodiment of the present invention.

Figure 7 is a schematic illustration of a topography removing abrasive member in accordance with an embodiment of the present invention.

Figure 8 is a schematic illustration of a CMP abrasive member in accordance with an embodiment of the present invention.

Figure 9 is an exploded view of an abrasive article with gimbaled abrasive members in accordance with an embodiment of the present invention.

Figure 10 is a perspective view of a preload mechanism for the abrasive article of Figure 9.

Figure 11 is a perspective view of a gimbal structure for the abrasive article of Figure 9. Figure 12 is a perspective view of the abrasive members for the abrasive article of Figure 9.

Figure 13A is another perspective view of the abrasive members for the abrasive article of Figure 9.

Figure 13B is a detailed perspective view of the fluid bearing surface on the abrasive members of Figure 9.

Figure 14A-14C is a detailed perspective view of the fluid bearing surface on the abrasive members of Figure 9 with various abrasive surface additives.

Figure 15 is a perspective view of a unitary abrasive article in accordance with an embodiment of the present invention.

Figure 16 is a perspective view of the gimbal assemblies of the abrasive article of Figure 15.

Figure 17 is a perspective view of the fluid bearing surfaces of the abrasive article of Figure 15.

Figure 18 is an exploded view of an abrasive article with an integral hydrostatic bearing structure in accordance with an embodiment of the present invention.

Figure 19 is a bottom view of the abrasive article of Figure 18 with the membrane removed.

Figure 20 is a detailed top view of the abrasive article of Figure 18 with the membrane removed.

Figure 21 is an exploded view of the hydrostatic abrasive member.

Figures 22 and 23 are perspective views of the hydrostatic abrasive member assembly of Figure 21.

Figure 24 is a bottom perspective view of the hydrostatic abrasive member assembly of Figure 21.

Figure 25 is a perspective view of an annular fluid bearing surface in accordance with an embodiment of the present invention.

Figure 26B is a pressure profile graph of the fluid bearing of Figure 26A.

Figure 27 is a perspective view of a hydrodynamic abrasive member in accordance with an embodiment of the present invention.

Figure 28 is a pressure profile generated at one of the pads for the abrasive member of Figure 27. Figure 29 is an exploded view of a hydrodynamic abrasive member assembly in accordance with an embodiment of the present invention.

Figure 30 is a perspective view of the hydrodynamic abrasive member assembly of Figure 29.

Figures 31A-31C are various views of a cylindrical array of abrasive members in accordance with an embodiment of the present invention.

Figure 32 is an exploded view of the cylindrical array of abrasive members of Figures 31A-31C.

Figure 33 is a plurality of the cylindrical array abrasive member assemblies of Figures 31A-31C in accordance with an embodiment of the present invention.

Figure 34 is a schematic illustration of an abrasive member for topography following applications in accordance with an embodiment of the present invention.

Figure 35 is a schematic illustration of an abrasive member for topography following applications in accordance with an embodiment of the present invention.

Figure 36 is a schematic illustration of an abrasive member for topography removing applications in accordance with an embodiment of the present invention.

Figures 37 illustrate a hydrodynamic abrasive member for use in CMP in accordance with an embodiment of the present invention.

Figure 38 illustrates a hydrostatic abrasive member for use in CMP in accordance with an embodiment of the present invention.

Figure 39 illustrates an alternate abrasive article with curved hydrodynamic fluid bearing surfaces in accordance with an embodiment of the present invention.

Figure 40 illustrates a hydrostatic version of the abrasive article of Figures 39 in accordance with an embodiment of the present invention.

Figure 41 illustrates an alternate abrasive article with integrated fluid delivery through a gimbal in accordance with an embodiment of the present invention.

Figure 42 illustrates an alternate abrasive article of Figure 41 with consumable design in accordance with an embodiment of the present invention.

Figure 43 illustrates an alternate arrangement of abrasive article of Figure 41 in accordance with an embodiment of the present invention. Detailed Description of the Invention

Figure 9 is an exploded view of an abrasive article 50 with an array of gimballed abrasive members 52 in accordance with an embodiment of the present invention. The abrasive article 50 includes gimbal structure 54, preload mechanism 56, and the abrasive members 52. The abrasive article 50 can be manufactured in circular and non-circular shapes. The abrasive members 52 can be arranged in a regular pattern a random

configuration, an off-set pattern or a variety of other configurations.

Figure 10 provides a detailed view of the preload mechanism 56 of Figure 9. The preload mechanism 56 includes a series of outer rings 58 each with a plurality of preload beams 60 configured to apply a preload on each of the abrasive members 52. The preload applied by the beams 60 is preferably concentrated toward the center of the abrasive members 52 so as to not interfere with pitch and roll motions during polishing. A dimple 61 at the end of the load beam 60 pushes against the abrasive member to transfer preload.

Figures 11 and 12 illustrate the gimbal structure 54 of Figure 9. Framework 62 supports an array of gimbal assemblies 64. In the illustrated embodiment, each gimbal assembly 64 includes one or more arms 66, a cross member 68 with attachment features 72. The gimbal assemblies 64 allow each of the abrasive members 52 to independently follow millimeter-scale and micrometer-scale waviness of the substrate during polishing.

The gimbal assemblies 54 control the static attitude or pitch of each abrasive member 52. The arms 66 and cross members 68 permit the abrasive members 52 to move through at least pitch and roll, while assuring adequate torque is applied to the abrasive members 52. The members 66 and 68 can be configured to promote topography following or topography removing behavior in the abrasive members 52. Various alternate gimbal assemblies are disclosed in U.S. Pat. Nos. 5,774,305; 5,856,896; 6,069,771; 6,459,260;

6,493,192; 6,714,386; 6,744,602; 6,952,330; 7,057,856; and 7,203,033.

Figure 12 illustrates the array of abrasive members 52 prior to assembly onto the gimbal assemblies 64. The abrasive members 52 can be made from a variety of materials, such as for example, metal, ceramic, polymers, or composites thereof. The abrasive members 52 are preferably arranged in a random or off-set pattern to impart a uniform polishing pattern onto the substrate.

As illustrated in Figure 12, shear forces between the rotating substrate 107 and the abrasive article 52 entrain an air cushion that applies fluid dynamic lift on fluid bearing surfaces 94 and 98 on the abrasive member 52. The dynamic lift causes the abrasive members 52 to assume a fly attitude during the relative rotation of a substrate 107. The fluid bearing developed allows the abrasive members 52 to follow the micrometer-scale and/or millimeter- scale wavelengths of waviness ("waviness") on the substrate 107, while removing nanometer- scale and/or micrometer-scale height variations. Typically, the leading edges 94 of the abrasive members 52 generate a lift countering the cutting forces.

Since each of the abrasive members 52 can independently adjust to the waviness of the substrate 107 and maintain a constant cutting force/pressure, the amount of material removed across the substrate 107 is substantially uniform. The present embodiment is particularly well suited to remove a uniform amount of an oxide layer on a semiconductor. The ability of the abrasive members 52 to follow the waviness enables uniform material removal at a level not attainable by conventional CMP processes.

Figures 13A and 13B illustrate one possible geometry of the fluid bearing surface 90 of the abrasive members 52. The fluid bearing surfaces 90 include various fluid bearing features 92 that promote the creation of a fluid bearing with the substrate 107. In the illustrated embodiment, leading edge 92 of the fluid bearing surface 90 includes a pair of pressure pads separated. The trailing edge 98 includes is formed from pressure pad. A discussion of the lift created by rotating rigid disks is provided in U.S. Pat. No. 7,218,478.

In one embodiment, the pads 92 and 98 can be formed with a crown and cross- curve. The leading edges 94 are optionally tapered or stepped to help initiate aerodynamic lift. For air bearing type bearings a negative suction force areas can be generated in the fluid bearing surface 90 to stabilize the abrasive members 52 during flying. The fluid bearing surface 90 can also include trenches to enable higher pressurization during the flying.

Figure 13B illustrates the addition of a hard coating on the polishing surfaces 96 A and 96B. In one embodiment the DLC is applied by chemical vapor deposition. As used herein, the term "chemically vapor deposited" and "CVD" refer to materials deposited by vacuum deposition processes, including, but not limited to, thermally activated deposition from reactive gaseous precursor materials, as well as plasma, microwave, DC, or RF plasma arc-jet deposition from gaseous precursor materials. Various methods of applying a hard coat to a substrate are disclosed in U.S. Pat. Nos. 6,821,189 (Coad et al); 6,872,127 (Lin et al); 7,367,875 (Slutz et al.); and 7,189,333 (Henderson), which are hereby incorporated by reference.

Figures 14A-C are a schematic representation of the abrasive members 52 with the addition of various abrasive elements to the surface in accordance with an embodiment of the present invention. Nano diamonds are added to the bearing surfaces 96 A, 96B and 96C.

In another embodiment, nano-diamonds (i.e., with a major diameter less than 1 micrometer) are attached to the pads 96, 100 via existing processes (CVD encapsulation, brazing, adhesives, embedding, etc.). Methods of uniformly dispersing nanometer size abrasive grains are disclosed in U.S. Pat. Pub. No. 2007/0107317 (Takahagi et al.), which is hereby incorporated by reference. Various geometrical features and arrangement of abrasive particles on abrasive articles are disclosed in U.S. Pat. Nos. 4,821,461 (Holmstrand), 3,921,342 (Day), and 3,683,562 (Day), and U.S. Pat. Pub. No. 2004/0072510 (Kinoshita et al), which are hereby incorporated by reference. A two-step adhesion process for attaching diamonds to the pads 96, 100 is disclosed in U.S. Pat. Nos. 7,198,553 and 6,123,612, which are hereby incorporated by reference.

Figure 14B illustrates abrasive particles 340, such as nano-scale diamonds, attached to a polyamide backing layer 342 located on the pads 96 that act as the abrasive features in accordance with an embodiment of the present invention. In another embodiment, a slurry of nano-scale diamonds and adhesive are spin coated, sprayed coated, or otherwise deposited directly onto the pads 96.

Figures 14C illustrates perspective and side views of an engineered surface imparted to the pads 96A-C in accordance with an embodiment of the present invention. The engineered surface is preferably nanometer-scale or micrometer-scale. A hard coat, such as DLC, is preferably applied to the engineered surface.

The engineered surface allows for precise stress management between the polished substrate and the nano-features. Such precise stress management yields a predictable surface finish and the gap allows for residual material to be removed. Various engineered surfaces 130 are disclosed in U.S. Pat. Nos. 6,194,317 (Kaisaki et al); 6,612,917 (Bruxvoort); 7,160,178 (Gagliardi et al.); 7,404,756 (Ouderkirk et al.); and U.S. Publication No. 2008/0053000 (Palmgren et al.), which are hereby incorporated by reference.

In another embodiment, a slurry of abrasive particles is located at the interface between the abrasive element and the, such as for example, in a standard chemical- mechanical polishing process. Various methods of chemical-mechanical processing are disclosed in U.S. Pat. No. 6,811,467 (Beresford et al.) and U.S. Pat. Publication Nos.

2004/0072510 (Kinoshita et al.) and 2008/0004743 (Goers et al.), which are hereby incorporated by reference. In some embodiments, the abrasive members 52 are manufactured with one or more sensors to monitor the polishing process, such as for example, acoustic emission or friction sensor. The present interference lapping preferably results in a surface finish or roughness (Ra) of less than about 20 Angstrom, and more preferably less than about 0.2 Angstrom.

Figures 15-16 illustrate a fully integrated gimbaled abrasive article 150 in accordance with an embodiment of the present invention. Preload structure 152 includes circumferential ribs 154 and radial ribs 156 to impart a desired preload onto abrasive members 158. Gimbal assemblies 160 include a collection of flexible ribs 162, 164 connecting the preload structure 152 to the abrasive members 158. The abrasive article 150 is preferably fabricated as a single unit, such as by injection molding. The fabrication process can include multiple mold injection steps to meet the system requirements.

Instead of applying the preload directly to the abrasive members 158, the preload is applied by the preload structure 152 through the gimbal assemblies 160. This configuration is ideal for low preload applications. Care must be taken not to cause excessive deformation of the gimbal assemblies 160 during preload applications. Figure 16 illustrates fluid bearing features fabricated on the abrasive members 158, such as discussed above. The fluid bearing surfaces can include any of the abrasive features discussed herein.

Figure 17 presents a view of an alternate abrasive article 358 in which the fluid bearing features 352A, 352B, 352C ("352") include a plurality of grooves 354 oriented generally parallel to the direction of travel of the abrasive members 358 relative to the substrate. The grooves 354 release fluid located at the interface between the fluid bearing features 352, reducing the lift on the abrasive members 358.

The grooves 354 reduce the fly height of the abrasive members 358. In applications where the fluid is a liquid, the grooves 354 permit a low fly height and/or a low preload. The grooved abrasive members 358 are particularly well suited to fully flooded applications.

The depth of the grooves 354 must be sufficient to reduce hydrodynamic pressure between the abrasive members 358 and the substrate. In most cases, the grooves 354 have a depth of greater than about 5 micrometers.

By reducing the hydrodynamic film, it is possible to use lubricants with a higher viscosity and/or maintain a low preload on each abrasive member 358, while still achieving interference with the substrate. In some applications, the grooves 354 allow a reduction in the hydrodynamic film while allowing the use of nano-scale diamonds attached to the fluid bearing features 352.

In one embodiment, nano-scale diamonds attached to a polymeric film, such as illustrated in Figure 14B, are attached to the fluid bearing features 352. The grooves 354 permit the load on the abrasive members 358 to be sufficiently low. In another embodiment, the fluid bearing features 352 are grooved abrasive composites. The grooves 354 also permit the fly height to be engineered for particular applications. Assuming all other processing variables are held constant, increasing the size or number of grooves 354 reduces fly height, and hence, increases interference between the substrate. The spacing height of the abrasive members 358 above the substrate can also be engineered, such as by changing the size and shape of the fluid bearing features 352.

Figures 18-20 illustrate an alternate abrasive article 200 with an array of abrasive members 212 having an integrated hydrostatic bearing structure 202 in accordance with an embodiment of the present invention. Membrane 216 seals gas conduits 204 in the bearing structure 202.

Figures 19 and 20 illustrate the integrated hydrostatic bearing structure 202 without sealing membrane 216 shown. Gas conduits 204 are fabricated in gimbal assembly 206 and along preload ribs 208. Holes 210 extending through the abrasive members 212 to fluid bearing surfaces 214 (see Figure 19). The gas conduits 204 are externally pressurized to provide a hydrostatic bearing on each abrasive member 212. The fluid bearing surfaces 214 can include any of the abrasive features discussed herein.

As best illustrated in Figure 19, fluid bearing surfaces 214 of the abrasive members 212 are fabricated with button pressure ports 218 to form a hydrostatic bearing on each abrasive member 212. The hydrostatic bearing generated at each fluid bearing surface 214 is designed to counter the cutting forces during the polishing process. For illustrative purposes, a button bearing design is shown. Additional configurations can easily be adapted such as multiple ports onto each abrasive member 212 to enable the abrasive member to form a pitch and roll moment.

In one preferred embodiment, a pressure port 218 is located near the leading edges 220 to increase the pitch of the abrasive members 212 for topography following applications. In another embodiment, pressure ports 218 are located at both the leading edges 220 and trailing edges 222 of the abrasive members 212 to configure the pitch for topography removing applications. The abrasive article 200 is particularly useful when the relative speed between the substrate and the abrasive members 212 is not high enough to form a fluid bearing or hydrodynamic film. The external pressure applied to the abrasive members 212 forms a hydrostatic film capable of following the substrate waviness and countering the cutting forces emanating from the interference between the peaks of the abrasive member 200 and the substrate.

The hydrostatic fluid bearing may be used in combination with a hydrodynamic fluid bearing. In one embodiment, the hydrostatic fluid bearing is used during start-up rotation and/or ramp-down of the abrasive article 200 relative to a substrate.

A preferred method for making the abrasive composites 312 having precisely shaped abrasive composites 312 is described in U.S. Pat. No. 5,152,917 (Pieper et al) and U.S. Pat. No. 5,435,816 (Spurgeon et al.), both incorporated herein by reference. Other descriptions of suitable methods are reported in U.S. Pat. Nos. 5,437,754; 5,454,844 (Hibbard et al.); U.S. Pat. No. 5,437,7543 (Calhoun); and U.S. Pat. No. 5,304,223 (Pieper et al.), all incorporated herein by reference.

Production tools for making the abrasive members may be in the form of a belt, a sheet, a continuous sheet or web, a coating roll such as a rotogravure roll, a sleeve mounted on a coating roll, or die. The production tool may be made of metal, (e.g., nickel), metal alloys, or plastic. The production tool is fabricated by conventional techniques, including photolithography, knurling, engraving, hobbing, electroforming, or diamond turning. For example, a copper tool may be diamond turned and then a nickel metal tool may be electroplated off of the copper tool. Preparations of production tools are reported in U.S. Pat. No. 5,152,917 (Pieper et al.); U.S. Pat. No. 5,489,235 (Gagliardi et al.); U.S. Pat. No. 5,454,844 (Hibbard et al.); U.S. Pat. No. 5,435,816 (Spurgeon et al.); PCT WO 95/07797 (Hoopman et al.); and PCT WO 95/22436 (Hoopman et al.), all incorporated herein by reference. In an alternate embodiment, the abrasive members are used in combination with the gimbal mechanism such as disclosed in Figure 9.

Figure 21-24 give a perspective view of hydrostatic abrasive article 550 with an array of hydrostatic abrasive members 552 in accordance with an embodiment of the present invention. External pressure source 554 is applied to each of the abrasive members 552 to control clearance 556 with the substrate 558. Preload 612 biases the abrasive members 552 toward the substrate 558. Polishing is accomplished by relative motion between the hydrostatic abrasive article 550 and the substrate 558, such as linear, rotational, orbital, ultrasonic, and the like.

Figure 21 is an exploded view of the hydrostatic abrasive article 550 of Figure 31. External pressure source 554 delivers pressurized gas (e.g., air) to plenum 600 in preload structure 602. Cover 604 is provided to enclose the plenum 600. A plurality of pressure ports 606 in the plenum 600 are fluidly coupled to the pressure ports on the gimbal mechanism 590 by bellows couplings 608.

Springs 610 transfer the preload 612 from the preload structure 602 to each of the gimbal mechanisms 590. The externally applied load 612, the geometry of the

hydrostatic bearing 564, 572, and the external pressure control the desired spacing 556 between the abrasive members 552 and the substrate 558.

Holder structure 620 is attached to the preload structure 602 by stand-offs 622. The holder structure 620 sets the preload 624 applied on each abrasive member 552 and limits the deformation of the gimbal mechanisms 590 in order to avoid damage while the individual preload 624 is applied. An adhesive layer (not shown) attaches the abrasive members 552 to the gimbal box-like structure 594. The external preload 612 applied to the array of abrasive members 552 is greater than or equal to the preloads 624 generated by the independently suspended abrasive members 552 in order to allow the gimbal mechanisms 590 to comply with the substrate 558 and not interfere with the holder structure 620.

Figures 22 and 23 illustrate dimple structure 630 interposed between the springs 610 and the gimbal mechanism 590. The dimple structure 630 delivers the preload as a point source. Offset from the springs 610 and the dimple 630 is a flexible bellow 608 that delivers the external pressure to each individual abrasive member 552 via the gimbal mechanisms 590. The gimbal mechanisms 590, preload structure 602, and holder structure 620 can also be used in a hydrodynamic application without the pressure ports 566 and bellows couplings 608.

Figure 23 is a bottom view of the hydrostatic abrasive article 550 with the individual abrasive members 552 organized in a serial fashion. Note that other configurations can easily be accommodated, such as for example an off-set or random pattern.

Controlling the magnitude of the pressure applied to the abrasive members changes the clearance between the substrate and the abrasive members. The frequency response of the system is independent of the compliance of the material selected for the abrasive member but can be engineered by the selection of the gimballing mechanism, including the hydrostatic bearing design. The pressure generated by the hydrostatic bearing contributes to forming pitch, z-height, and roll forces that counter the cutting forces emanating from surface defects interaction and potential contact with the substrate.

The hybrid abrasive member 552 can operate with a hydrostatic fluid bearing and/or a hydrodynamic fluid bearing. The hydrostatic pressure ports 566 apply lift to the abrasive member 552 prior to movement of the substrate 558. The lift permits clearance 556 to be set before the substrate 558 starts to move. Consequently, preload 612 does not damage the substrate 558 during start-up. Once the substrate 558 reaches its safe speed and the hydrodynamic fluid bearing is fully formed, the hydrostatic fluid bearing can be reduced or terminated. The procedure can also be reversed at the end of the polishing process.

Figure 24 illustrates a gimbal assembly 588 that contains an array of gimbal mechanisms 590 of Figure 21. Each gimbal mechanism 590 includes four L-shaped springs 592A, 592B, 592C, 592D (collectively "592") that suspend the abrasive members 552 above the substrate 558 in accordance with an embodiment of the present invention. Box-like structure 594 is optionally fabricated on each gimbal structure 590 to help align the abrasive members 552. The box-like structure 594 also includes a port 596 that delivers the pressurized gas to the backs of the abrasive members 552 and out the pressure ports 566.

Figure 25 illustrates an embodiment of an individual abrasive member 552 with both hydrostatic and hydrodynamic fluid bearing capabilities designed into bottom surface 560 in accordance with an embodiment of the present invention. The bottom surface 560 of the abrasive member 552 includes both air bearing features 564 and pressure ports 566.

Leading edge 562 of the abrasive member 552 includes a pair of fluid bearing pads 564A, 564B (collectively "564") each with at least one associated pressure port 566A, 566B. Trailing edge 570 also includes a pair of fluid bearing pads 572A, 572B (collectively "572") and associated pressure ports 566C, 566D.

The fluid bearing pads 564 A, 564B are fabricated on the trailing edge 570. The leading edge 562 typically flies higher than the trailing edge 570, which sets the pitch of the abrasive member 552 relative to the substrate 558. The trailing edge 574, 564A, and 564B is typically designed to be in interference with the surface defects on the substrate 558. Both leading edge and trailing edge structures 562, 570 contribute to controlling the amount of interference with substrate. It is also possible to control the pressure applied to the pressure ports 566 A, 566B at the leading edge 562 to increase or decrease the pitch of the abrasive member 552.

Figure 26A illustrates a circular hydrostatic abrasive member 640 in accordance with an embodiment of the present invention. The cylindrical shaped recess 642 and pressure port 644 create a generally constant pressure at center, with a logarithmical decaying pressure radially outward.

Figure 26B is a graphical illustration of the pressure profile for the circular abrasive member of Figure 38. The circular abrasive member has a generally constant pressure profile 646 in center region 642 adjacent to the pressure port 644. The pressure at the outer edges 648 of the abrasive member matches ambient pressure. This pressure profile operates similar to a nonlinear spring. One embodiment envisions a cylindrical shaped recess, such as 642, at each corner of the abrasive member 560 of Figure 25.

Figure 27 illustrates a hydrodynamic abrasive member 650 in accordance with an embodiment of the present invention. The abrasive member 650 is generally the same as discussed above, except that no pressure ports are required. Fluid bearing surfaces 652A, 652B, 652C, 652D, 652E (collectively "652") located along the leading edge 654 and trailing edge 656 create hydrodynamic lift between the abrasive member 650 and the substrate. The air for the fluid bearing enters along the leading edge 654 and exits along the trailing edge 656. The fluid bearing surfaces 652 also enhance the stability at the interface and a cutting surface to remove surface defects from the substrate.

The conditions promoting hydrodynamic lift are bearing design, gas/liquid shearing, and linear velocity of the abrasive member 650 relative to the substrate. Such conditions can promote the formation of a fluid film (oil, water, gas) between the abrasive member and the substrate. The relative velocity is obtained by rotating the substrate and/or the abrasive members 650.

Figure 28 illustrates a pressure curve generate by the abrasive member 650 of Figure 27 at each pressure pad. Note that the pressure vanishes to atmospheric pressure at the edges of the fluid bearing surfaces and builds-up to a maximum 672 at the trailing edge fluid bearing surfaces 652C, 652D, 652E. Each of the fluid bearing surfaces pressurizes under the shear force of the lubricating fluid (air or liquid) to generate a pressure force contributing to lift and countering the cutting forces emanating from the polishing or polishing operation. The pressure formed under the fluid bearing surfaces maintains a certain clearance between the substrate 658 and the abrasive members 650. Figure 29-30 offer a hydrodynamic abrasive article 670 of the present embodiment. An array of abrasive members 650 is attached to preload structure 660 by an array of gimbal mechanisms 662. Preload 664 is transmitted to the gimbal mechanisms 662 by dimpled springs 666, generally as discussed above. The suspended abrasive members 650 have a static pitch and roll stiffness through the hydrodynamic fluid bearing and a z-stiffness through the gimbal mechanisms 662. The fluid bearing surfaces 652 can include any of the abrasive features discussed herein.

The hydrodynamic fluid film formed at each abrasive member 650 controls the dynamic response of the structure. The frequency response of such system can be designed to be in the 5-100 kHz range, which is sufficient to comply with the substrate surface 668 and to interact with surface debris. The spacing between the polishing surfaces 652C, 652D, 652E can be controlled to cause interaction with surface defects with little to no material removal from the substrate 658. In order for the fluid bearing surfaces 652 to develop a stable interface, the hydrodynamic forces must be greater than external

disturbances caused by the interference or contact between the polishing surfaces 652C, 652D, 652E and the surface defects.

Figures 31A-31C illustrate an abrasive member assembly 750 with an array of abrasive members 768 arranged in a cylindrical array in accordance with an embodiment of the present invention. Figure 32 is an exploded view of the abrasive member assembly 750 ofFigure 31A-31C.

The abrasive member 750 preferably forms a contact interface with the substrate, although this embodiment may be used with a hydrodynamic or hydrostatic bearing. Cylinder preload fixture 752 includes a plurality of dimpled spring members 754 that apply an outward radial preload 756 on each gimbal mechanism 758. The preload 756 is transferred by dimple member 760 acting on rear surface 762 of the gimbal mechanisms 758. The gimbal mechanisms 758 are interconnected into a gimbal assembly 764 by support structure 766. The individual abrasive members 768 are attached to the gimbal mechanisms 758.

Figures 32-33 illustrate a plurality of the abrasive member assemblies 750 of Figure 45 arranged in a stack configuration 782. The cylindrical structure can be used to clean planar or non-planar substrates. In one embodiment, axis of rotation 780 is oriented parallel to the surface 784 of the substrate 786. The stacked configuration 782 is optionally rotated while engaged with the substrate 786. The substrate 786 can be stationary or moving. A hydrostatic bearing can optionally be generated at the interface of the abrasive members 768 and the substrate via external pressurization means, as discussed above. The hydrostatic approach permits the abrasive members 768 to hover over the substrate surface at any desired clearance while still being able to interact and remove surface defects. A stable contacting interface can also be used with the abrasive members 768. The abrasive members 768 can either be a porous sponge-like material or a hard coated slider. The gimbal mechanisms 758 and preload mechanisms 754 permit the abrasive members 768 to follow the run-out and waviness of the substrate while the abrasive members 768 intimately contact and clean the substrate.

Controlling the magnitude of the pressure applied to the abrasive members changes the clearance between the substrate and the abrasive members. The frequency response of the system is independent of the compliance of the material selected for the abrasive members but can be engineered by the selection of the gimballing mechanism, including the hydrostatic bearing design. The pressure generated by the hydrostatic bearing contributes to forming pitch, z-height and roll forces that counter the cutting forces emanating from surface defects interaction and potential contact with the substrate.

Example 1

Figure 34 illustrates an abrasive member 800 modeled for topography following applications. The leading edge 802 includes a plurality of discrete features 804 separated by cavities 806 that permit air flow and particles to enter. The cavity depth 812 is about 2 micrometers to about 3 micrometers to promote a negative suction force in the presence of air as a lubricant.

The front of the leading edge pads 804 are rounded to promote the redistribution of debris and lubricant. This example of a low contact force abrasive member 800 includes leading edge step 818 that increases lift at the leading edge 802. The modeled air bearing structure forms a positive lift from the pressurization of the bearing surface pads and a negative suction force located in the cavity of the air bearing. The design presented tradeoff the air bearing pitch angle with the cutting force increase due to a preload increase as demonstrated in Table 1.

Table 1 shows that the leading edge 802 clears the substrate, while the trailing edge 810 is in contact. This approach permits the trailing edge 810 to follow the substrate waviness. The leading and trailing edge pressurization contribute to the stability of the design during asperity interactions and debris removal. This design is ideal for cleaning debris and removing nano level amounts of material in the presence of a thin film lubricant.

Table 1

Example 2

Figure 35 illustrates an abrasive member 820 modeled for topography following applications. The leading edge 822 includes a plurality of discrete features 824 separated by slots 826 that permit air flow and particles to enter. This example of a low contact force abrasive member 820 includes leading edge step 828 and extended sides 830 to increase the negative pressure force (suction force). The leading edge step 828 has a depth of about 0.1 micrometers to about 0.5 micrometers to promote the formation of higher pressure at the leading edge 822.

Note that the trailing edge 832 is formed of discrete pads 834 to reduce the spacing between the substrate and the abrasive member, and to allow for circulation of lubricant and debris.

Table 2 provides a summary of various performance parameters for the abrasive member as a function of preload. Table 2

Example 3

Figure 36 illustrates an abrasive member 840 modeled for topography removing applications. The leading edge 842 includes a plurality of discrete features 844 separated by slots 846 that permit air flow and particles to enter. The trailing edge 848 similarly includes a plurality of discrete features 850 separated by slots 852. The features 844, 850 have of about 2 micrometers with respect to the cavity 830 and are formed with rounded leading edge surfaces to distribute both lubricant and wear debris.

The cavity depth is sufficient to create a positive pressure profile at the top of the pads 844, 850 and a negative suction force. The proper selection of the pressure distributions controls the pitch angle of the abrasive member 840 and the minimum spacing above the substrate.

In the case of topography removing, the abrasive member 840 does not follow certain target wavelengths of waviness. The pitch angle of the abrasive member 840 is therefore substantially reduced to cause both the leading edges 842 and the trailing edges 848 to not follow the target wavelengths of waviness and to cause wear of the interacting surfaces.

A simple exercise demonstrates the capability of this design given in Table 3. By varying the externally applied preloads from about 0.1 grams to about 10 grams, a reduction in the pitch angle and spacing is attained, causing a higher level of wear and interactions between both the leading and trailing edges 842, 848 and the substrate. The low pitch angle also inhibits follow of the target wavelengths. Note that at 5 grams of preload a negative suction force and a total positive pressure is generated to counter the contact force of 2.56 grams and the 5 grams of preload. An increase in preload as shown causes a substantially linear increase in contact force responsible for the removal of material at the substrate.

Table 3 provides a summary of various performance parameters for the abrasive member as a function of preload.

Table 3

Example 4

Figure 37 illustrates an abrasive member 870 for use with free abrasive particles, such as in CMP. Leading edge pressurization 882 causes the abrasive member 870 to pitch upward so leading edge 872 does not contact the substrate. The pitch also contributes to the ability of the abrasive member 870 to follow the topography of the substrate.

Spacer rails 876 at trailing edge 874 help set a known spacing between the free abrasives (not shown) and the polishing recessed surface 880. The distance between the surface 880 and the spacer rails 876 must be smaller than the average size of the free abrasives to ensure intimate contact of the polishing recessed surface 880 with the free abrasives. The rails 876 control the spacing between the abrasive member 870 and the substrate and provide a predictable interference between the trapped free abrasive particles and the substrate.

A series of shaped recessed polishing surfaces 880 are fabricated at the trailing edge 874 between the rails 876 to interact with the free abrasive particles present in the chemical mechanical polishing slurry. The recesses have a depth 882 of about 10 nanometers to about 200 nanometers relative to rails 876, which is smaller than the diameter of the free abrasive particles. The leading edges 884 of the recessed pads 880 are shaped to allow progressive entrance of the free abrasive particles to the interface of the abrasive member 870 with the substrate.

The design presents a leading edge 884 pressurized zone and a trailing edge 874 pressurized zone. The trailing edge 874 is able to both follow the topography while the recessed polishing surfaces 880 cause the free abrasive particles to be in intimate contact with the substrate. The resulting contact pressure is substantially uniform and independent of the substrate topography.

Example 5

Figure 38 illustrates abrasive member 900 for use with free abrasive particles, similar to CMP. In the case of conditions where a hydrodynamic film is difficult to establish, such as for example in the case of slow spinning plates and the presence of large amount of debris interfering with the formation of a hydrodynamic film, it is desirable to switch to a hydrostatic bearing concept.

One or more button bearings 902, 914 are fabricated at the leading edge 906, such as illustrated in Figures 26A and 26B. Pad 908 is formed at the trailing edge 910. The pad 908 includes ramp 912 that promotes movement of the free abrasive particles into the interface with the substrate. The trailing edge 910 is in contact with the slurry, causing the free abrasive particles to contact the surface and remove material. The hydrostatic bearing establishes a stable bearing and assures topography following. The hydrostatic bearing provides a substantially constant polishing pressure across the substrate.

Example 6

Figure 39 illustrates an abrasive article 1150 with an array of abrasive member 1152 with integrated preload applied through the platform 1174 and gimbal structure 1156 in accordance with an embodiment of the present invention. The illustrated abrasive members 1152 includes spherical fluid bearing structures 1180 each shown with a spherical or cylindrical curvature. The illustrated curvature is substantially exaggerated to illustrate the concept. Each abrasive member 1152 includes a plurality of extensions 1156 that contribute to forming an individual gimballing assembly. The extensions 1156 are mounted to tabs 1172 on preload pad 1174, such as for example, by an adhesive, solvent bonding, ultrasonic welding, and the like. The extensions 1156 can flex and twist on either side of the tabs 1172 so the abrasive members 1152 can be independently displace vertically, and in pitch and roll. For ease of manufacturing the abrasive members 1152 and extension 1156 are molded as a unitary structure.

Preload members are positioned between the preload pad (underneath the spherical abrasive member) and rear surfaces 1158 of the abrasive members 1152. The preload members are preferably resilient to permit deflection of the abrasive members 1152 in the vertical direction. The preload members are preferably attached to either the preload pad 1174 or the abrasive members 1152.

The abrasive members 1152 optionally include one or more cavities or steps 1180 near leading edge to promote formation of a fluid bearing. By changing the curvature of the fluid bearing surface, the shape or location of the cavities, or a variety of other variables, the abrasive members can be either topography following or topography removing. The spherical configuration permits a progressive interactions with free abrasives. The spherical shape also allows for a elliptical contact with desirable topography following properties.

Example 7

Figure 40 illustrates an abrasive article 1200 with an array of abrasive member 1202 substantially with hydrostatic ports 1204 in accordance with an embodiment of the present invention. The hydrostatic ports 1204 are preferably button bearings located at leading edges 1206 of the abrasive members 1202.

Rear surfaces 1208 of each abrasive member 1202 includes channels that fluidly communicate with opening in sealing layer 1214. The openings fluidly communicate with holes 1216 in preload members 1226. Rear surface of preload pad 1218 includes a series of channels and backing layer 1224. As a result, a pressurized gas delivered to the channels flows through the backing layer, to the preload pad channels, in the abrasive members ports and out the pressure ports 1204. Example 8

Figure 41 gives an exploded view of a configuration with a distant preload cartridge comprising a dimple holder 1565, a spring preload 1563 and a spring housing 1561 attached to a preload cartridge holder 1520. The preload cartridge holder contains a series of hydrostatic ports 1521. The spring housing connects the hydrostatic pressure from the preload cartridge holder to the gimball assembly. A four-layer gimball assembly 1541, 1542, 1543, and 1544 delivers the inlet hydrostatic pressure to the abrasive member cover 1582 through a series of springs. The abrasive member assembly is formed with a top membrane 1582 attached to an air flow channel member 1583. The abrasive member 1590 contains the hydrostatic bearing arrangement. The pressurized air is supplied by opening mating the air flow channel member 1583 and the abrasive member 1590.

Figure 42 shows an abrasive member 1590 with a series of hydrostatic ports organized in a concentric manner. A channel 1610 at atmospheric pressure boundary condition connects hydrostatic button bearings 1600.

Figure 43 shows a ganged arrangement of abrasive members 1590. Each abrasive member is independently gimbaled and preloaded to perform desired polishing operations.

Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range is encompassed within the inventions. The upper and lower limits of these smaller ranges which may independently be included in the smaller ranges is also

encompassed within the inventions, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either both of those included limits are also included in the inventions.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which these inventions belong. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present inventions, the preferred methods and materials are now described. All patents and publications mentioned herein, including those cited in the Background of the application, are hereby incorporated by reference to disclose and describe the methods and/or materials in connection with which the publications are cited.

An abrasive article for polishing a surface of a substrate, the abrasive article includes a gimbal structure, a plurality of abrasive members, a preload mechanism and a fluid beaming feature on the abrasive article. The gimbal structure includes a plurality of gimbal assemblies. The abrasive members comprie a first surface engaged with one of the gimbal assemblies, and a second surface. The gimbal assemblies permit each abrasive member to move independently along a pitch axis and a roll axis. The preload mechanism biases the second surface of the abrasive members toward the substrate. The fluid bearing feature is located on the second surface of at least some of the plurality of the abrasive members. The fluid bearing is configured to generate lift forces during motion of the abrasive article relative to the substrate. In some embodiments, the fluid bearing feature comprises an abrasive material attached to the second surface of the abrasive member. In still other embodiments, the abrasive article further includes a slurry of free abrasive particles located at the interface of the second surface and the substrate. In one embodiment, the plurality of abrasive members comprises an interconnected array of molded abrasive members. The abrasive members can be in a patterned array. The pattern can include a circular array, a rectangular array, or an off-set pattern. In another embodiment, the array is a random pattern. The abrasive article of claim 1 wherein the fluid bearing feature comprises a fluid bearing feature a leading edge of the second surface and a fluid bearing surface at a trailing edge of the second surface of the abrasive members. The fluid bearing feature of the abrasive article can include abrasive composites.

An abrasive article for polishing a surface of a substrate includes an integrated structure and a including a plurality of gimbal assemblies and a plurality of preload structures. The a plurality of abrasive members each includes a first surface and a second surface. The first surface is engaged with one of the integrated gimbal assemblies and one of the preload structures. The second surface is for polishing the substrate. The gimbal assembly, to which the abrasive member is attached, permits the abrasive member to move independently in at least pitch and roll, The preload structure biases the second surface of the abrasive member toward the substrate. One or more fluid bearing features on the second surface of the abrasive member generate lift forces during motion of the abrasive article relative to the substrate. In some embodiments, the bearing structure is a hydrostatic bearing structure while in other embodiments, the bearing structure is a hydrodynamic bearing structure. In still other embodiments, the abrasive features include abrasives attached to the fluid bearing features of the abrasive members. The plurality of abrasive members can include an interconnected array of molded abrasive members. In some embodiments, the abrasive members comprise a cylindrically shaped bearing surface. The abrasive members can also include a grooved bearing surface. In other words, the bearing surface can have a groove or grooves therein. In another embodiment, the abrasive features include an abrasive material attached to the second surface of the abrasive members, a slurry of free abrasive particles located at the interface of the second surface and the substrate, or a combination thereof.

An abrasive article for polishing a substrate includes a plurality of interconnected abrasive members wherein at least some of the plurality of interconnected abrasive members include at least one bearing structure. The abrasive members further include a first surface and a second surface. An abrasive feature is located on the second surface of the abrasive members. The abrasive feature applies a cutting or a contact force to the substrate during motion of the abrasive article relative to the substrate. The bearing structure can be a hydrostatic bearing structure or a hydrodynamic bearing structure. Abrasives can be attached to the abrasive feature of the abrasive member. In some embodiments, the plurality of interconnected abrasive members include an interconnected array of molded abrasive members. The abrasive members can be set forth in an array. The second surface can also be cylindrically shaped. The second surface also can have a groove therein. An abrasive feature can also include one or more abrasive materials attached to the second surface of the abrasive members, the abrasive article. In some embodiments, the abrasive article further includes a slurry of free abrasive particles located at the interface of the second surface and the substrate.

An apparatus for polishing a surface of a substrate includes a gimbal structure including an array of gimbal assemblies; and preload mechanism that biases the array of gimbal assemblies toward the substrate. Some embodiments of the apparatus include a plurality of gas conduits adapted to deliver pressurized gas to one or more pressure ports positioned opposite the substrate. Other embodiments of the invention are possible. Although the description above contains much specificity, these should not be construed as limiting the scope of the invention, but as merely providing illustrations of some of the presently preferred embodiments of this invention. It is also contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the inventions. It should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the disclosed inventions. Thus, it is intended that the scope of at least some of the present inventions herein disclosed should not be limited by the particular disclosed embodiments described above.

Thus the scope of this invention should be determined by the appended claims and their legal equivalents. Therefore, it will be appreciated that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the present invention is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean "one and only one" unless explicitly so stated, but rather "one or more." All structural, chemical, and functional equivalents to the elements of the above-described preferred embodiment that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the present invention, for it to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims.

Claims

What is claimed is:

1. An abrasive article for polishing a surface of a substrate, the abrasive article comprising:

a gimbal structure including a plurality of gimbal assemblies; a plurality of abrasive members comprising a first surface engaged with one of the gimbal assemblies, and a second surface, the gimbal assemblies permitting each abrasive member to move independently along a pitch axis and a roll axis;

a preload mechanism that biases the second surfaces of the abrasive members toward the substrate; and

a fluid bearing feature on the second surface of at least some of the plurality of the abrasive members configured to generate lift forces during motion of the abrasive article relative to the substrate.

2. The abrasive article of claim 1 wherein the fluid bearing feature comprises an abrasive material attached to the second surface of the abrasive member.

3. The abrasive article of claim 1 further comprising, a slurry of free abrasive particles located at the interface of the second surface and the substrate.

4 The abrasive article of claim 1 wherein the plurality of abrasive members comprises an interconnected array of molded abrasive members.

5. The abrasive article of claim 1 wherein the plurality of abrasive members are arranged in a patterned array

6. The abrasive article of claim 1 wherein the plurality of abrasive members are arranged in a random pattern.

7. The abrasive article of claim 1 wherein the fluid bearing feature comprises a fluid bearing feature a leading edge of the second surface and a fluid bearing surface at a trailing edge of the second surface of the abrasive members.

8. The abrasive article of claim 1 wherein the fluid bearing features include abrasive composites.

9. An abrasive article for polishing a surface of a substrate, the abrasive article comprising:

an integrated structure including a plurality of gimbal assemblies and a plurality of preload structures;

a plurality of abrasive members each comprising

a first surface engaged with one of the integrated gimbal assemblies and one of the preload structures; and

a second surface for polishing the substrate,the gimbal assembly, to which the abrasive member is attached, permitting the abrasive member to move

independently in at least pitch and roll, the preload structure biasing the second surface of the abrasive member toward the substrate; and

fluid bearing features on the second surface of the abrasive member generate lift forces during motion of the abrasive article relative to the substrate.

10. The abrasive article of claim 9 wherein the bearing structure is a hydrostatic bearing structure.

11. The abrasive article of claim 9 wherein the bearing structure is a hydrodynamic bearing structure.

12. The abrasive article of claim 9 wherein the abrasive features comprise abrasives attached to the fluid bearing features of the abrasive members.

13. The abrasive article of claim 9 wherein the plurality of abrasive members comprises an interconnected array of molded abrasive members.

14. The abrasive article of claim 9 wherein the abrasive members comprise a cylindrically shaped bearing surface.

15. The abrasive article of claim 9 wherein the abrasive members comprise a grooved bearing surface.

16. The abrasive article of claim 9 wherein the abrasive features comprise abrasive material attached to the second surface of the abrasive members, a slurry of free abrasive particles located at the interface of the second surface and the substrate, or a combination thereof.

17. An abrasive article for polishing a substrate, the abrasive article comprising:

a plurality of interconnected abrasive members wherein at least some of the plurality of interconnected abrasive members comprise at least one bearing structure, the abrasive members including a first surface and a second surface; and

an abrasive feature located on the second surface of the abrasive members, the abrasive feature applying a cutting or a contact force to the substrate during motion of the abrasive article relative to the substrate.

18. The abrasive article of claim 17 wherein the bearing structure is a hydrostatic bearing structure.

19. The abrasive article of claim 17 wherein the bearing structure is a hydrodynamic bearing structure.

20. The abrasive article of claim 17 wherein the abrasive feature comprise abrasives attached to the abrasive feature of the abrasive member.

21. The abrasive article of claim 17 wherein the plurality of interconnected abrasive members comprise an interconnected array of molded abrasive members.

22. The abrasive article of claim 17 wherein the abrasive members comprise a cylindrically shaped second surface.

23. The abrasive article of claim 17 wherein the abrasive members comprise a second surface having a groove therein.

24. The abrasive article of claim 17 wherein the abrasive feature comprises one or more of an abrasive materials attached to the second surface of the abrasive members, the abrasive article further comprising a slurry of free abrasive particles located at the interface of the second surface and the substrate.

25. An apparatus for polishing a surface of a substrate, the apparatus comprising:

a gimbal structure including an array of gimbal assemblies; and a preload mechanism that biases the array of gimball assemblies toward the substrate.

26. The apparatus of claim 25 further comprising a plurality of gas conduits adapted to deliver pressurized gas to one or more pressure ports positioned opposite the substrate.