Abrasive-containing high-strength polishing pad

Abstract

To provide a polishing pad having a strength against destruction even when polishing is carried out by increasing workpiece polishing pressure to enhance polishing performance.SOLUTION: Resin hollow spheres 38 are three-dimensionally disposed in a polishing pad 18, and the hollow spheres 38 are coupled by a base material resin 40, and a communication space 42 between the hollow spheres 38 is filled with polishing abrasives 36. Thus, as the hollow spheres 38 coupled by the base material resin 40 form a wall structure, the polishing pad 18 strong enough to resist destruction even when high-load polishing is carried out by increasing polishing pressure against a workpiece 16 is provided. In the polishing pad 18, the hollow spheres 38 in the polishing pad 18 are deformed to convert vertical pressure received from the workpiece 16 into horizontal pressure and extrudes the polishing abrasives 36 to the surface layer of the polishing pad 18, thereby increasing the polishing abrasives 36 on a polishing surface. Thus, action abrasives 36a brought into contact with the workpiece 16 increase, and a polishing rate RP is increased.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an abrasive grain-containing polishing pad used to polish one surface of a workpiece such as a glass substrate or a semiconductor substrate, and to a high-strength polishing pad that enables high-load polishing processing. [Background technology]

[0002] Abrasive-containing polishing pads are known, which include a porous base resin having interconnected pores and a large number of abrasive grains contained in the longitudinal interconnected pores formed in the base resin. Such abrasive-containing polishing pads are also called LHA (Loosely Held Abrasive) pads, and because they do not use abrasive-containing slurry as a polishing liquid, they consume less abrasive grains and reduce environmental impact. For example, the abrasive-containing polishing pads described in Patent Documents 1 and 2 are examples of such pads.

[0003] In the abrasive grain-containing polishing pad described in Patent Document 1, abrasive grains are self-supplied between the polishing pad and the workpiece, so when used in CMP (chemical mechanical polishing) methods, there is no need to use a slurry containing expensive abrasive grains, thereby reducing the economical costs and increased environmental impact associated with disposing of used slurry.

[0004] The abrasive-containing polishing pad described in Patent Document 2 includes a porous resin matrix with interconnected pores, numerous abrasive grains contained within the longitudinally extending interconnected pores, and large pores formed between the interconnected pores by the resin matrix, each with a larger cross-sectional area than the interconnected pores. When pressure is applied during polishing, a micropumping effect (pressure pressing the polishing pad to push the abrasive grains in the interconnected pores toward the large pores) causes the abrasive grains contained within the interconnected pores to move into the large pores that communicate with the interconnected pores, resulting in a large number of abrasive grains remaining within the large pores on the surface. This increases the number of active abrasive grains that come into contact with the underside of the workpiece, thereby improving polishing efficiency. This effect is particularly pronounced with abrasive grains that are irregularly shaped (non-spherical), such as ceria particles, making them difficult to move. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-025415 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-049256 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the abrasive grain-containing polishing pads described in Patent Documents 1 and 2, the base resin is columnar (fibrous) in order to form longitudinal, interconnected pores that contain the abrasive particles. Therefore, when the polishing pressure on the workpiece is increased to improve the polishing efficiency, the base resin may be insufficiently strong, causing the polishing pad to break and making polishing difficult.

[0007] The present invention was made against the background of the above circumstances, and its purpose is to provide an abrasive grain-containing polishing pad that is strong enough to withstand high load polishing by increasing the polishing pressure on the workpiece in order to improve polishing efficiency.

[0008] Based on the above background, the inventors conducted extensive research and found that by arranging hollow resin spheres (microballoons) three-dimensionally within an abrasive grain-containing polishing pad, bonding the hollow spheres with a matrix resin, and filling the interconnected spaces between the hollow spheres with abrasive grains, the hollow spheres bonded by the matrix resin form a wall structure, resulting in a highly durable abrasive grain-containing polishing pad that will not break even when high-load polishing pressure is applied to the workpiece. Furthermore, the inventors found that in such an abrasive grain-containing polishing pad, the hollow spheres within the polishing pad deform to convert the vertical pressure from the workpiece into lateral pressure, pushing the abrasive grains toward the surface of the polishing pad, thereby increasing the amount of abrasive grains on the polishing surface. The hollow spheres open to the polishing surface act as reservoirs for abrasive grains to be supplied between the polishing pad and the workpiece, increasing the number of active abrasive grains that come into contact with the workpiece, thereby improving polishing efficiency. The present invention was made based on this finding. [Means for solving the problem]

[0009] In other words, the gist of the first invention is a high-strength polishing pad containing abrasive grains used to polish one surface of a workpiece using the CMP method, which comprises hollow resin spheres, a base resin that bonds the hollow spheres, and abrasive grains filled in the communicating spaces between the hollow spheres.

[0010] The gist of the second invention is that in the first invention, the base resin is made of a hydrophilic resin, and the hollow spheres are made of a non-hydrophilic resin.

[0011] The gist of the third invention is that in the second invention, the hydrophilic resin is a polyethylene glycol-based acrylic resin.

[0012] The gist of the fourth invention is that in the third invention, the monomer of the polyethylene glycol-based acrylic resin before hardening of the base resin is a combined resin of polyethylene glycol diacrylate and dipentaerythritol hexaacrylate.

[0013] The gist of the fifth invention is that in the second invention, the non-hydrophilic resin is an acrylic resin or a vinylidene chloride resin.

[0014] The gist of the sixth invention is that in the first invention, the abrasive grains are at least one of ceria, manganese oxide, silica, alumina, titania, zirconia, and iron oxide. [Effects of the Invention]

[0015] According to the first invention, a high-strength abrasive-containing polishing pad contains hollow resin spheres (microballoons) arranged three-dimensionally within the pad, bonded by a resin matrix, and filled with abrasive grains in the interconnected spaces between the spheres. The hollow spheres bonded by the resin matrix form a wall structure, resulting in a high-strength abrasive-containing polishing pad that is strong enough to withstand high-load polishing, even when subjected to high-pressure polishing. Furthermore, in a high-strength abrasive-containing polishing pad with this structure, the hollow spheres within the pad deform to convert vertical pressure from the workpiece into lateral pressure, pushing the abrasive grains toward the surface of the pad, increasing the amount of abrasive grains on the polishing surface. The hollow spheres open to the polishing surface act as reservoirs for abrasive grains to accumulate between the pad and the workpiece, increasing the amount of active abrasive grains that come into contact with the workpiece, thereby improving polishing efficiency.

[0016] In the second invention of the high-strength polishing pad containing abrasive grains, the base resin is made of a hydrophilic resin and the hollow spheres are made of a non-hydrophilic resin. During polishing using an aqueous polishing liquid, the base resin softens but the hollow spheres do not, so the strength of the high-strength polishing pad is maintained.

[0017] According to the third invention of the high-strength polishing pad containing abrasive grains, the hydrophilic resin is a polyethylene glycol-based acrylic resin, so that when polishing using an aqueous polishing liquid, the base resin has an appropriate elasticity, and repeated pressure from the workpiece can effectively produce a micro-pumping effect that pushes the polishing grains to the surface.

[0018] According to the fourth invention of the abrasive grain-encapsulated high-strength polishing pad, the monomer of the polyethylene glycol-based acrylic resin before hardening of the base resin is a combination of polyethylene glycol diacrylate and dipentaerythritol hexaacrylate, which provides the base resin with an appropriate hardness, thereby achieving a favorable polishing rate and surface roughness.

[0019] According to the fifth invention, the non-hydrophilic resin constituting the hollow spheres is an acrylic resin or a vinylidene chloride resin, which prevents the hollow spheres from softening during polishing with an aqueous polishing liquid, resulting in a high-strength polishing pad containing abrasive grains that is strong enough to withstand high-load polishing without breaking.

[0020] According to the sixth invention of the high-strength polishing pad containing abrasive grains, the abrasive grains are at least one of ceria, manganese oxide, silica, alumina, titania, zirconia, and iron oxide. In particular, even with irregular (non-spherical) abrasive grains such as ceria, the abrasive grains in the communicating spaces are pushed toward the large pores by the micro-pumping action caused by repeated elastic deformation of the hollow spheres. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a perspective view conceptually showing the configuration of a polishing device to which an abrasive grain-containing polishing pad according to one embodiment of the present invention is applied; [Figure 2] 2 is a plan view for schematically explaining rotation holes of an attachment disk of the polishing processing device of FIG. 1. FIG. [Figure 3] 2 is an SEM photograph of a cross section for explaining the configuration of a polishing pad having hollow spheres used in the polishing processing apparatus of FIG. 1. FIG. [Figure 4] 2 is a cross-sectional view for explaining the structure of the polishing pad having the hollow sphere of FIG. 1. FIG. [Figure 5] 2 is a schematic diagram illustrating the micro-pumping action of the polishing pad having the hollow sphere of FIG. 1. FIG. [Figure 6] FIG. 2 is a diagram showing the composition ratio of the polishing pad having hollow spheres in FIG. 1 in comparison with the polishing pad having large pores in Patent Document 2. [Figure 7] FIG. 2 is a diagram showing the basic chemical structure of a hydrophilic resin that constitutes the base resin in the abrasive grain-containing polishing pad of FIG. [Figure 8] FIG. 2 is a diagram showing the chemical structure of dipentaerythritol hexaacrylate (monomer), which is a material constituting the hydrophilic resin that constitutes the base resin in the abrasive grain-containing polishing pad of FIG. [Figure 9] FIG. 2 is a diagram showing the chemical structure of PEG400# diacrylate (n=9), which is a material constituting the hydrophilic resin that constitutes the base resin in the abrasive grain-containing polishing pad of FIG. [Figure 10] FIG. 2 is a diagram showing the chemical structure of PEG600# diacrylate (n=14), which is a material constituting the hydrophilic resin that constitutes the base resin in the abrasive grain-containing polishing pad of FIG. [Figure 11] 1 is a table showing the results of an evaluation conducted by the inventors of the combination ratio of dipentaerythritol hexaacrylate with PEG400# diacrylate (n=9) or PEG600# diacrylate (n=14) and the polishing ability of the polishing pad. [Figure 12] 1A to 1C are process diagrams illustrating a manufacturing process of a polishing pad. [Figure 13] 1 is a graph showing changes in polishing rate during polishing tests of polishing pads obtained in polishing tests conducted by the present inventors under different polishing loads, in comparison with the polishing pad of Patent Document 2. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0022] An embodiment of the present invention will be described in detail below with reference to the drawings. Note that in the following embodiment, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of the various parts are not necessarily drawn accurately. [Example]

[0023] Fig. 1 conceptually shows the main components of a surface polishing apparatus 10 employing an abrasive grain-containing high-strength polishing pad (hereinafter referred to as "polishing pad") 18 according to one embodiment of the present invention, with the guide roller fixing base 28 removed. In Fig. 1, the surface polishing apparatus 10 is provided with a polishing platen 12 rotatably supported about a vertical rotation axis C1, and the polishing platen 12 is driven by a platen drive motor 14 to rotate at a constant speed in one rotation direction indicated by the arrow in Fig. 1. A polishing pad 18 having a diameter of, for example, about 300 mm is attached to the upper surface of the polishing platen 12, i.e., the surface against which one surface of a workpiece (glass plate or semiconductor substrate) 16 is pressed.

[0024] The workpiece 16 is held on the lower surface of the attachment disc 20, i.e., the surface facing the polishing pad 18, and the attachment disc 20 presses the workpiece 16 against the polishing pad 18 with a predetermined load. A drip nozzle 22 is provided near the attachment disc 20 of the surface polishing device 10, and a polishing liquid (lubricant) 26 containing no abrasive grains is delivered from a polishing liquid supply device 24 and supplied onto the polishing surface plate 12. When the workpiece 16 is a glass plate, water is used as the polishing liquid 26.

[0025] The surface polishing apparatus 10 is optionally provided with an adjustment tool holder (not shown) that is rotatable about a rotation axis C1 parallel to the rotation axis C1 of the polishing table 12 and that is movable in the direction of the rotation axis C1 and in the radial direction of the polishing table 12, and an abrasive body adjustment tool (dresser or conditioner) such as a diamond wheel (not shown) that is attached to the lower surface of the adjustment tool holder, i.e., the surface facing the polishing pad 18. The adjustment tool holder and the abrasive body adjustment tool attached thereto are pressed against the polishing pad 18 while being rotated by an adjustment tool drive motor (not shown), and are moved back and forth in the radial direction of the polishing table 12, thereby adjusting the polishing surface of the polishing pad 18 and constantly maintaining the surface condition of the polishing pad 18 in a state suitable for polishing.

[0026] 2, at a position eccentric from the rotation axis C1 on the polishing table 12, a short cylindrical application disk 20 holds the workpiece 16, or the object to be polished, on its underside by suction, adhesion, or a holding frame, etc. The outer surface of the application disk 20 is supported by a pair of free-rotating guide rollers 30 and a drive guide roller 32 mounted on a fixed guide roller support base 28 fixed to a frame (not shown), allowing the application disk 20 to rotate about the rotation axis C2. The application disk 20 is rotated about the rotation axis C2 by a rotational force based on the difference in peripheral speed between the polishing table 12 and the polishing pad 18, and the application disk 20 is pressed against the polishing pad 18 on the polishing table 12 by the load of, for example, a weight 34, thereby polishing the workpiece 16.

[0027] The following polishing method is used for polishing using the surface polishing apparatus 10. The polishing platen 12 and the polishing pad 18 attached thereto, and the attachment disk 20 and the workpiece (silicon wafer) 16 held on its underside are rotated about their respective rotation axes C1 and C2 by the platen drive motor 14 and drive guide roller 32. While a polishing liquid 26 containing no abrasive grains is supplied onto the surface of the polishing pad 18 from the drip nozzle 22 and a spray nozzle (not shown), the workpiece 16 held on the attachment disk 20 is pressed against the polishing pad 18. As a result, the polished surface of the workpiece 16, i.e., the surface facing the polishing pad 18, is polished flat by the mechanical polishing action of the abrasive grains 36 contained within and self-supplied from the polishing pad 18. When the workpiece 16 is a glass plate, ceria is used as the abrasive grains 36.

[0028] As shown in the SEM photograph of FIG. 3 and the schematic diagram of FIG. 4, the polishing pad 18 attached to the polishing surface plate 12 includes a matrix resin 40 that bonds hollow spheres 38 arranged three-dimensionally within the polishing pad 18, and abrasive grains 36 that fill the interconnected spaces 42 formed by the matrix resin 40 between the hollow spheres 38. The hollow spheres (microballoons) 38 are hollow and made of a non-hydrophilic resin, such as an acrylic resin or a vinylidene chloride resin. The particle diameter of the hollow spheres 38 is, for example, 20 μmφ to 60 μmφ, and the particle diameter of the abrasive grains 36 is, for example, 6 nmφ to 1720 nmφ. The abrasive grains 36 are selected from at least one of ceria, manganese oxide, silica, alumina, titania, and zirconia. In FIG. 3, 38s denotes the shell of the hollow sphere 38.

[0029] In the polishing pad 18 having the hollow spheres 38 configured in this manner, the hollow spheres 38 are bonded together in close proximity to each other, forming a relatively rigid wall structure, thereby enhancing strength. Because the hollow spheres 38 bonded together by the matrix resin 40 form a wall structure, the polishing pad 18 has high strength and is not damaged even when high-load polishing pressure is applied to the workpiece 16. As shown in FIG. 5 , the hollow spheres 38 in the polishing pad 18 elastically deform to convert the vertical pressure from the workpiece 16 into lateral pressure, pushing the abrasive grains 36 toward the surface of the polishing pad 18, thereby increasing the amount of abrasive grains 36 on the polishing surface. The inside of the hollow spheres 38 that open to the polishing surface act as a reservoir for the abrasive grains 36 to be supplied between the polishing pad 18 and the workpiece 16. This increases the amount of active abrasive grains that come into contact with the underside of the workpiece 16, contributing to high polishing efficiency.

[0030] The base resin 40 is made of a hydrophilic resin, such as a polyethylene glycol-based acrylic resin, and the hollow spheres 38 are made of a non-hydrophilic resin, such as an acrylic resin or a vinylidene chloride resin. During polishing using an aqueous polishing liquid 26, the base resin 40 softens, but the hollow spheres 38 do not, thereby maintaining the strength of the high-strength polishing pad. As a result, the base resin 40 is appropriately softened. As shown in FIG. 5, when the polishing pad 18 is repeatedly pressed against the workpiece 16, the hollow spheres 38 elastically deform into a horizontally elongated shape, and the abrasive grains 36 contained in the interconnected spaces 42 of the base resin 40 are pushed to the surface of the polishing pad 18, creating a micropumping effect.

[0031] The polishing pad 18 of this embodiment has, for example, the volume ratio shown in Figure 6. Figure 6 shows a comparison with a polishing pad of the conventional structure described in Patent Document 2 (comprising a porous base resin having interconnected pores, a large number of abrasive grains contained in longitudinal interconnected pores formed in the base resin, and large-diameter pores formed between the interconnected pores by the base resin and having a larger cross-sectional area than the interconnected pores). The polishing pad 18 of this embodiment does not have a significant difference in the volume of abrasive grains compared to the polishing pad with large pores of Patent Document 2, but the volume of the base resin (PEG400# diacrylate (n=9) used) 40 is more than twice the volume of the base resin (PES resin) of the polishing pad of Patent Document 2, the volume of the hollow sphere 38 is slightly larger, about 1.2 times the volume of the large pores of the polishing pad of Patent Document 2, the volume of the communicating space 42 is less than 1 / 3 the volume of the communicating pores of the polishing pad of Patent Document 2, and the hardness of the polishing pad 18 measured with a durometer hardness tester is about 1.5 times higher than the hardness of the polishing pad of Patent Document 2.

[0032] The base resin 40 is composed of, for example, a polyethylene glycol-based acrylic resin basically having the chemical structure shown in FIG. 7. The monomer of this polyethylene glycol-based acrylic resin is a combination resin of dipentaerythritol hexaacrylate (monomer) shown in FIG. 8 and PEG400# diacrylate (n=9) shown in FIG. 9 or PEG600# diacrylate (n=14) shown in FIG. 10. According to tests conducted by the inventors, these combinations preferably have a dipentaerythritol hexaacrylate ratio of 10 vol% to 20 vol%, as shown in FIG. 11. If the dipentaerythritol hexaacrylate ratio is 0 vol%, the base resin 40 swells, and if the dipentaerythritol hexaacrylate ratio is 100 vol%, the base resin 40 becomes hard, and neither is suitable for polishing.

[0033] FIG. 12 is a process diagram illustrating the manufacturing process of the polishing pad 18. In FIG. 12, in the resin blending step P1, dipentaerythritol hexaacrylate and PEG400# diacrylate (n=9), which are materials for the base resin 40, are blended and mixed so that the dipentaerythritol hexaacrylate content is 10 to 20 vol%. Next, in the polymerization initiator mixing step P2, the polymerization initiator AIBN is mixed with the blended resin. In the subsequent resin stirring step P3, the polymerization initiator AIBN and the blended resin are stirred. Next, in the abrasive grain mixing step P4, abrasive grains (ceria) 36 are added and stirred. Then, in the hollow sphere mixing step P5, hollow spheres 38 are added and stirred to form a slurry. Next, in the molding step P6, the pad is molded into a plate of a predetermined thickness using a casting method or a doctor blade method. Then, in the curing step P7, the polymerization of the resin is accelerated by heating, and the slurry molded to a predetermined thickness is cured.

[0034] (Experimental example) Below, we will explain a polishing test that the inventor conducted using polishing pad 18 under polishing test conditions to measure the change over time in the polishing rate PR (μm / min) of polishing pad 18, with the pressing load of workpiece 16 against polishing pad 18 as a parameter.

[0035] (Polishing test conditions) Equipment: 380mmφ single-sided polishing machine Workpiece: Synthetic quartz (100mmφ×1mmt) [1 piece] Plate rotation speed: 60 rpm Work rotation speed: 60 rpm Test time: 300 min Polishing liquid: Water (city water) (10ml / min) Dresser: Diamond pellet (#400) for 2 minutes before polishing test Polishing pad: High-strength polishing pad with embedded abrasive grains (abrasive grains: average primary particle diameter 27 nm [measured by laser particle size distribution analyzer: particle diameters D10 = 6 nm φ, D50 = 0.78 nm φ, D90 = 1.72 nm φ], ceria 17.9 vol%, hollow spheres: average particle outer diameter 40 μm φ, acrylic resin 34.2 vol%, base resin: polyethylene glycol-based acrylic resin 36.4 vol%, hardness: 60.5 (durometer hardness Type-D))

[0036] 12 shows the polishing rate PR (μm / min) measured over time when polishing was performed under the above polishing conditions using a conventional abrasive-containing polishing pad described in Patent Document 2 and a high-strength abrasive-containing polishing pad (polishing pad 18) of this example at two different polishing loads (20 kPa, 40 kPa). In FIG. 12, the polishing rate PR when the conventional abrasive-containing polishing pad described in Patent Document 2 was used at a polishing load of 20 kPa and 40 kPa is shown by △ and ▲. In addition, the polishing rate PR when the high-strength abrasive-containing polishing pad of this example was used at a polishing load of 20 kPa and 40 kPa is shown by ○ and ●. According to FIG. 12, when the polishing load was 20 kPa, there was not much difference between the polishing rate PR of the conventional abrasive-containing polishing pad and the polishing rate PR of the high-strength abrasive-containing polishing pad of this example. However, when the polishing load was 40 kPa, the polishing rate PR of the conventional structured abrasive-containing polishing pad was higher than that when the polishing load was 20 kPa, but the polishing pad was damaged after 30 minutes of polishing.In contrast, with the abrasive-containing high-strength polishing pad of this embodiment, a polishing rate PR of about 1.8 times that of the polishing load of 20 kPa was obtained until the polishing time of 300 minutes had elapsed.In other words, the abrasive-containing high-strength polishing pad of this embodiment made it possible to perform high-load, high-efficiency polishing.

[0037] As described above, in the polishing pad 18 of this embodiment, hollow resin spheres (microballoons) 38 are arranged three-dimensionally within the polishing pad 18, and these hollow spheres 38 are bonded together with a matrix resin 40, with abrasive grains 36 filling the communicating spaces 42 between these hollow spheres 38. As a result, the hollow spheres 38 bonded together with the matrix resin 40 form a wall structure, and an abrasive grain-encapsulated high-strength polishing pad 18 is obtained that has such high strength that it will not break even when high-load polishing is performed by increasing the polishing pressure on the workpiece 16. Furthermore, in the abrasive grain-containing high-strength polishing pad 18 having such a structure, the hollow spheres 38 inside the polishing pad 18 convert the vertical pressure received from the workpiece 16 into lateral pressure through their deformation, and push the abrasive grains 36 out onto the surface of the polishing pad 18, thereby increasing the amount of abrasive grains 36 on the polishing surface.The inside of the hollow spheres 38 that open to the polishing surface become a reservoir where the abrasive grains 36 accumulate and supply the abrasive grains 36 between the polishing pad 18 and the workpiece 16, so that the amount of active abrasive grains 36a that come into contact with the workpiece 16 increases, and the polishing rate PR is improved.

[0038] In the polishing pad 18 of this embodiment, the base resin 40 is made of a hydrophilic resin, and the hollow spheres 38 are made of a non-hydrophilic resin. Therefore, during polishing using the aqueous polishing liquid 26, the base resin 40 softens, but the hollow spheres 38 do not, so the strength of the polishing pad 18 is maintained.

[0039] According to the polishing pad 18 of this embodiment, the base resin 40 is a polyethylene glycol-based acrylic resin, and therefore, when polishing using the aqueous polishing liquid 26, the base resin 40 has an appropriate elasticity, and repeated pressure from the workpiece 16 produces an optimal micro-pumping effect that pushes the polishing grains 36 to the surface.

[0040] In the polishing pad 18 of this embodiment, the monomer of the polyethylene glycol-based acrylic resin before hardening of the base resin 40 is a combination resin of polyethylene glycol diacrylate and dipentaerythritol hexaacrylate, which provides the base resin 40 with an appropriate hardness, thereby achieving a favorable polishing rate PR and polished surface roughness.

[0041] In the polishing pad 18 of this embodiment, the non-hydrophilic resin constituting the hollow spheres 38 is an acrylic resin or a vinylidene chloride resin. This prevents the hollow spheres 38 from softening during polishing with the aqueous polishing liquid 26, and provides a polishing pad 18 with high strength that will not break even when polished under high loads.

[0042] In the polishing pad 18 of this embodiment, the abrasive grains 36 are at least one of ceria, manganese oxide, silica, alumina, titania, zirconia, and iron oxide. In particular, even if the abrasive grains 36 are irregular (non-spherical) in shape, such as ceria particles, the abrasive grains 36 in the communicating spaces 42 are pushed toward the large-diameter pores by the micro-pumping action caused by repeated elastic deformation of the hollow spheres 38.

[0043] Although one embodiment of the present invention has been described above, the present invention can also be applied in other aspects.

[0044] For example, in the surface polishing apparatus 10 of the above embodiment, the polishing liquid 26 is aqueous, but it may be a polishing liquid made of an organic amine and water, or an organic amine, an alkaline agent and water.

[0045] Furthermore, although a polyethylene glycol-based acrylic resin was used for the base resin 40, other hydrophilic resins may also be used, such as PES resin having a hydrophilic group, rigid foamed polyurethane resin, polyamide, polyamideimide, polyimide, polyacrylonitrile, polyvinylidene fluoride, cellulose acetate, polyvinyl alcohol, polyvinyl acetate, polyethylene glycol (molecular weight of 1000 or more), polyester, polyolefin-based resin, non-foamed polyurethane, and PVA.

[0046] Furthermore, although acrylic resin or vinylidene chloride resin is used for the hollow sphere 38, other non-hydrophilic resins may also be used.

[0047] Although not specifically exemplified, the present invention can be used with various modifications within the scope of the invention. [Explanation of symbols]

[0048] 16: Workpiece, 18: Polishing pad (high-strength polishing pad containing abrasive grains), 36: Polishing grains, 38: Hollow sphere, 40: Base resin, 42: Communicating space

Claims

1. A high-strength polishing pad containing abrasive grains used to polish one surface of a workpiece using a CMP method, A hollow sphere made of resin, a matrix resin that bonds the hollow spheres; and polishing grains filled in the communicating spaces between the hollow spheres. A high-strength polishing pad containing abrasive grains.

2. The matrix resin is made of a hydrophilic resin, and the hollow spheres are made of a non-hydrophilic resin.

2. The high-strength polishing pad according to claim 1, wherein the polishing pad has an abrasive grain encapsulation.

3. The hydrophilic resin is a polyethylene glycol-based acrylic resin.

3. The high-strength polishing pad according to claim 2, wherein the abrasive grains are contained therein.

4. The monomer of the polyethylene glycol-based acrylic resin before curing of the base resin is a combination resin of polyethylene glycol diacrylate and dipentaerythritol hexaacrylate.

4. The high-strength polishing pad according to claim 3, wherein the abrasive grains are contained therein.

5. The non-hydrophilic resin is an acrylic resin or a vinylidene chloride resin.

3. The high-strength polishing pad according to claim 2, wherein the abrasive grains are contained therein.

6. The abrasive grains are at least one of ceria, manganese oxide, silica, alumina, titania, zirconia, and iron oxide.

2. The high-strength polishing pad according to claim 1, wherein the polishing pad has an abrasive grain encapsulation.

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