TW201620670A - Polishing pad and method for producing polishing pad - Google Patents

Abstract

The purpose of the present invention is to provide a polishing pad which is able to achieve a good balance between reduction of the processing time and prevention of scratches on a polished object. The present invention is a polishing pad comprising a base and a polishing layer laminated on the front surface of the base, and this polishing pad is characterized in that: the polishing layer comprises a resin binder and abrasive grains dispersed in the binder; the abrasive grains have an average grain diameter of from 2 [mu]m to 45 [mu]m (inclusive); the binder has a durometer D hardness of from 60 to 88 (inclusive); the polishing layer has a plurality of projections in the surface; the projections have an average area of from 0.5 mm2 to 13 mm2 (inclusive); and the area occupancy of the plurality of projections in the whole polishing layer is from 5% to 40% (inclusive). It is preferable that the abrasive grains are diamond abrasive grains. It is preferable that the composition that constitutes the binder is mainly composed of a thermosetting epoxy resin. It is preferable that the plurality of projections are in a regularly arranged block pattern. It is preferable that an adhesive layer is provided on the back surface of the base.

Description

Method for manufacturing polishing pad and polishing pad

The present invention relates to a polishing pad and a method of manufacturing the polishing pad.

In recent years, the precision of electronic devices such as hard disks has been continuously developed. As a substrate material of such an electronic device, glass or the like can be used in consideration of rigidity, impact resistance, and heat resistance that can be reduced in size and thickness. When glass is used as the substrate, the mechanical strength may be significantly impaired by scratches on the surface. Therefore, it is necessary to prevent damage of the substrate during processing of the substrate.

In the processing of such a substrate (the object to be polished), a polishing pad for fixing abrasive grains is usually used, and in order to prevent damage of the object to be polished, for example, the shape of the polishing layer of the polishing pad and the particle size of the abrasive grains contained in the polishing layer are studied. Etc. (for example, refer to Japanese Patent Laid-Open Publication No. 2009-72832). In order to prevent damage to the object to be polished, the polishing pad uses relatively small abrasive grains having a particle diameter of less than 3 μm. However, since the particle size is small, it is necessary to lengthen the processing time, thereby requiring an improvement in production efficiency. [Prior Art Document] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2009-72832

[Problems to be solved by the invention]

The present invention has been made in view of the above circumstances, and an object thereof is to provide a polishing pad which can simultaneously achieve a reduction in processing time and prevention of damage of a workpiece. [Means for solving the problem]

As a result of intensive studies, the inventors of the present invention have found that the shape of the polishing layer and the hardness of the binder in which the abrasive grains are dispersed can be prevented from being damaged by the abrasive body even if the particle size of the abrasive grains is 3 μm or more. The present invention has thus been completed.

In other words, the invention has been made in order to solve the above problems, and is a polishing pad having a substrate and a polishing layer laminated on the surface side thereof, wherein the polishing layer has a resin binder and is dispersed therein. The abrasive grains in the binder, wherein the abrasive grains have an average particle diameter of 2 μm or more and 45 μm or less, and the D-type durometer D hardness of the binder is 60 or more and 88 or less. The surface has a plurality of convex portions, and the average area of the convex portions is 0.5 mm ² or more and 13 mm ² or less, and an area occupation ratio of the plurality of convex portions with respect to the entire polishing layer is 5% or more. And 40% or less.

Since the polishing pad has a D-type durometer hardness of the binder within the above range, the polishing layer has moderate elasticity. In addition, the polishing pad has a plurality of convex portions on the surface of the polishing layer, and an average area of the convex portions is within the range, and an area occupation ratio of the plurality of convex portions with respect to the entire polishing layer Within the above range, it is possible to prevent the object to be polished from being damaged, and to polish the object to be polished. By the moderate elasticity of the polishing layer and the effect of preventing damage, the polishing pad can make the average particle diameter of the abrasive grains within the above range, so that the processing time can be shortened and the damage of the object to be polished can be prevented at the same time.

The abrasive particles can be diamond abrasive particles. By using the abrasive grains as described above as the diamond abrasive grains, high polishing efficiency can be obtained, and the processing time can be shortened.

The composition constituting the binder may have a thermosetting epoxy resin as a main component. By using the thermosetting epoxy resin as a main component of the composition constituting the binder as described above, the D-type durometer hardness of the adhesive after heat curing can be easily made into the above range.

The shapes of the plurality of convex portions may be regularly arranged. By regularly arranging the shapes of the plurality of convex portions as described above, the anisotropy of polishing can be reduced, and the surface to be polished can be easily flattened.

An adhesive layer may be provided on the back side of the substrate. By having an adhesive layer on the back side of the substrate as described above, it can be easily and surely fixed to a support for attaching the polishing pad to the polishing apparatus.

The adhesive layer may be composed of an adhesive. Since the adhesive layer is made of an adhesive as described above, the polishing pad can be peeled off from the support and reattached, so that the polishing pad and the support can be easily reused.

Another invention completed in order to solve the above problems is a method for producing a polishing pad having a substrate and a polishing layer laminated on the surface side thereof, which comprises forming a composition for polishing the layer. The step of polishing the layer, wherein the polishing layer composition has a resin binder component and abrasive grains, and the abrasive grains have an average particle diameter of 2 μm or more and 45 μm or less, and the binder component is cured. The hardness of the D-type durometer is 60 or more and 88 or less. In the polishing layer step, an average area of 0.5 mm ² or more and 13 mm ² or less is formed on the surface of the polishing layer and is integrated with respect to the entire polishing layer. The convex portion having an area occupation ratio of 5% or more and 40% or less.

In the method for producing a polishing pad, since the polishing layer can be formed by applying the composition for the polishing layer, the production efficiency is good. Further, in the method for producing a polishing pad, the composition for the polishing layer has a D-type durometer hardness after curing, and the resin component in the range and the average particle diameter are abrasive grains in the above range, so that the convexity is convex. Since the average area of the shape and the area ratio of the convex portion to the entire polishing layer are within the above range, it is possible to manufacture a polishing pad which can simultaneously reduce the processing time and prevent damage of the object to be polished.

Here, the "average particle diameter" means a 50% value (50% particle diameter, D50) of a volume-based cumulative particle size distribution curve measured by laser diffractometry or the like. In addition, the "D-type durometer hardness" is a value measured according to the test method described in Japanese Industrial Standards (JIS)-K-7215:1986. Further, in the case where the polishing layer has a void, the "area of the entire polishing layer" is a concept including the area of the void. [Effects of the Invention]

As described above, according to the polishing pad of the present invention, it is possible to simultaneously shorten the processing time and prevent damage of the object to be polished. Therefore, the polishing pad can be preferably used for processing of a substrate or the like of an electronic device.

[First Embodiment] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

<Polishing Pad> The polishing pad 1 shown in FIGS. 1A and 1B includes a resin substrate 10, a polishing layer 20 laminated on the surface side of the substrate 10, and an adhesive layer 30 laminated on the back side of the substrate 10. .

(Substrate) The substrate 10 is a plate-like member for supporting the polishing layer 20.

The material of the substrate 10 is not particularly limited, and examples thereof include polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), and polyphthalate. Polyimide (PI), polyethylene naphthalate (PEN), aromatic aramid, aluminum, copper, and the like. Among them, PET and PI which are excellent in adhesion to the polishing layer 20 are preferable. Further, the surface of the substrate 10 may be subjected to a treatment for improving adhesion, such as chemical treatment, corona treatment, or primer treatment.

The shape and size of the substrate 10 are not particularly limited, and for example, it may be an annular shape having an outer shape of 200 mm or more and 2022 mm or less and an inner diameter of 100 mm or more and 658 mm or less. Alternatively, a plurality of substrates 10 juxtaposed on a plane may be supported by a single support.

The average thickness of the substrate 10 is not particularly limited, and may be, for example, 75 μm or more and 1 mm or less. In the case where the average thickness of the substrate 10 is less than the lower limit, the strength or flatness of the polishing pad 1 is insufficient. On the other hand, in the case where the average thickness of the substrate 10 exceeds the upper limit, the polishing pad 1 is unnecessarily thick and difficult to handle.

(Polishing Layer) The polishing layer 20 has a resin binder 21 and abrasive grains 22 dispersed in the binder 21. Further, the polishing layer 20 has a plurality of convex portions 23 on the surface.

The average thickness of the polishing layer 20 (only the average thickness of the portion of the convex portion 23) is not particularly limited, and the lower limit of the average thickness of the polishing layer 20 is preferably 25 μm, more preferably 30 μm. Further, the upper limit of the average thickness of the polishing layer 20 is preferably 1000 μm, more preferably 800 μm. In the case where the average thickness of the polishing layer 20 is less than the lower limit, the durability of the polishing layer 20 may be insufficient. On the other hand, in the case where the average thickness of the polishing layer 20 exceeds the upper limit, the polishing pad 1 is unnecessarily thick and difficult to handle.

(Binder) The lower limit of the hardness of the D-type durometer as the binder 21 is 60, and more preferably 70. Further, the upper limit of the hardness of the D-type durometer as the binder 21 is 88, and more preferably 80. When the hardness of the D-type durometer of the adhesive 21 is less than the lower limit, there is a possibility that the deformation of the polishing layer 20 is increased and the polishing is insufficient during the polishing treatment. On the other hand, when the hardness of the D-type durometer of the adhesive 21 exceeds the upper limit, the polishing layer 20 becomes hard, and thus the function of causing damage to the object to be polished or hindering the abrasive grains 22 may occur.

The composition constituting the binder 21 is not particularly limited, and a thermosetting resin can be used as a main component. Examples of the thermosetting resin include polyurethane, polyphenol, epoxy resin, polyester, cellulose, ethylene copolymer, polyvinyl acetal, polyacrylic acid, acrylate, polyvinyl alcohol, polyvinyl chloride, and the like. Polyvinyl acetate, polyamine, and the like. Among these, a thermosetting epoxy resin is preferable. When the thermosetting epoxy resin constitutes the binder 21, it is easy to ensure good dispersibility of the abrasive grains 22 and good adhesion to the substrate 10. Further, the D-type durometer hardness of the adhesive 21 after heat curing can be easily made into the above range.

The binder 21 may contain various additives such as a dispersing agent, a coupling agent, a surfactant, a lubricant, an antifoaming agent, and a coloring agent, and the like, as appropriate. Further, at least a part of the resin of the binder 21 may be crosslinked.

(Abrasive Grain) The abrasive grains 22 include particles such as diamond, alumina, and cerium oxide. Among them, it is preferred to obtain diamond abrasive grains having high polishing efficiency.

The lower limit of the average particle diameter of the abrasive grains 22 is 2 μm, more preferably 5 μm, still more preferably 10 μm. Further, the upper limit of the average particle diameter of the abrasive grains 22 is 45 μm, more preferably 20 μm, still more preferably 15 μm. In the case where the average particle diameter of the abrasive grains 22 is less than the lower limit, there is a possibility that the polishing rate becomes insufficient. On the other hand, when the average particle diameter of the abrasive grains 22 exceeds the upper limit, there is a possibility that the object to be polished is damaged or the polishing layer 20 is worn early.

The lower limit of the content of the abrasive grains 22 with respect to the polishing layer 20 is preferably 35% by volume, and more preferably 40% by volume. Further, the upper limit of the content of the abrasive grains 22 with respect to the polishing layer 20 is preferably 70% by volume, and more preferably 65% by volume. When the content of the abrasive grains 22 with respect to the polishing layer 20 is less than the lower limit, the polishing force of the polishing layer 20 may be insufficient. On the other hand, when the content of the abrasive grains 22 with respect to the polishing layer 20 exceeds the upper limit, the object to be polished is damaged.

(Convex Portion) The polishing layer 20 has a plurality of lattice-shaped convex portions 23 arranged at equal intervals on the surface. The shape of the plurality of convex portions 23 is a block pattern in which they are regularly arranged. The bottom surface of the portion (groove portion) other than the convex portion 23 of the polishing layer 20 is composed of the surface of the substrate 10.

The lower limit of the average area of the convex portion 23 is 0.5 mm ² , more preferably 2 mm ² , and still more preferably 4 mm ² . Further, the average area of the convex portion 23 of the upper limit is 13 mm ^2, more preferably 10 mm ^2, further preferably 8 mm ^2. When the average area of the convex portion 23 is smaller than the lower limit, the convex portion 23 of the polishing layer 20 may be peeled off. On the other hand, when the average area of the convex portion 23 exceeds the upper limit, the frictional resistance during polishing of the polishing layer 20 is increased, and the object to be polished is damaged.

The lower limit of the area occupation ratio of the plurality of convex portions 23 with respect to the entire polishing layer 20 is 5%, more preferably 12%, still more preferably 17%. Further, the upper limit of the area occupancy ratio of the plurality of convex portions 23 with respect to the entire polishing layer 20 is 40%, and more preferably 30%. When the area occupation ratio of the plurality of convex portions 23 with respect to the entire polishing layer 20 is smaller than the lower limit, the convex portion 23 of the polishing layer 20 may be peeled off. On the other hand, when the area occupying ratio of the plurality of convex portions 23 with respect to the entire polishing layer 20 exceeds the upper limit, the frictional resistance during polishing of the polishing layer 20 is increased, and the object to be polished is Suffering from injury.

(Next Layer) Next, the layer 30 is a layer in which the polishing pad 1 is fixed to a support for supporting the polishing pad 1 and attached to the polishing apparatus.

The adhesive used in the adhesive layer 30 is not particularly limited, and examples thereof include a reactive adhesive, an instant adhesive, a hot melt adhesive, and an adhesive.

The adhesive used in the adhesive layer 30 is preferably an adhesive. By using an adhesive as an adhesive used in the adhesive layer 30, the polishing pad 1 can be peeled off from the support and re-bonded, so that the polishing pad 1 and the support can be easily reused. The adhesive is not particularly limited, and examples thereof include an acrylic adhesive, an acrylic-rubber adhesive, a natural rubber adhesive, a synthetic rubber adhesive such as a butyl rubber, and an anthrone-based adhesive. A urethane-based adhesive, an epoxy-based adhesive, a polyethylene-based adhesive, a polyester-based adhesive, and the like.

The lower limit of the average thickness of the adhesive layer 30 is preferably 0.05 mm, more preferably 0.1 mm. Further, the upper limit of the average thickness of the adhesive layer 30 is preferably 0.3 mm, more preferably 0.2 mm. When the average thickness of the adhesive layer 30 is less than the lower limit, there is a possibility that the polishing pad is insufficient and the polishing pad is peeled off from the support. On the other hand, when the average thickness of the adhesive layer 30 exceeds the upper limit, for example, when the polishing pad is cut into a desired shape due to the thickness of the adhesive layer 30, workability such as an obstacle is lowered.

(Manufacturing Method of Polishing Pad) The polishing pad 1 can be produced by a step of preparing a composition for polishing a layer and a step of forming a polishing layer by coating a composition for a polishing layer.

First, in the polishing layer composition preparation step, a solution obtained by dispersing a polishing layer composition (formation material of the binder 21 and abrasive grains 22) in a solvent is prepared as a coating liquid. The solvent is not particularly limited as long as it can dissolve the material forming the binder 21 . Specifically, methyl ethyl ketone (MEK), isophorone, rosinol, N-methylpyrrolidone, cyclohexanone, propylene carbonate or the like can be used. In order to control the viscosity or fluidity of the coating liquid, a diluent such as water, an alcohol, a ketone, an acetate or an aromatic compound may be added.

Next, in the polishing layer forming step, the coating liquid prepared in the composition layer preparation step of the polishing layer is applied onto the surface of the substrate 10 to form the polishing layer 20 having the convex portion 23. In order to form the convex portion 23, a mask having a shape corresponding to the shape of the convex portion 23 is used. The shape of the mask is such that the average area of the convex portion 23 is 0.5 mm ² or more and 13 mm ² or less, and the area occupation ratio of the plurality of convex portions 23 with respect to the entire polishing layer is 5% or more. 40% or less is determined. The coating liquid was applied using the mask. As the coating method, for example, bar coating, reverse roll coating, knife coating, screen printing, or gravure coating can be used. , die coating, etc. Then, the polishing layer 20 is formed by drying and reacting the applied coating liquid. Specifically, for example, the solvent of the coating liquid is evaporated by heat of 100° C. or higher and 120° C. or lower, and the solvent of the coating liquid is cured by heat of 80° C. or higher and 120° C. or lower to form the binder 21 .

(Advantages) Since the polishing pad 1 has a D-type durometer hardness of 60 or more and 88 or less, the polishing layer 20 has moderate elasticity. In addition, the polishing pad 1 has a plurality of convex portions 23 on the surface of the polishing layer 20, and the average area of the convex portions 23 is 0.5 mm ² or more and 13 mm ² or less, and the plurality of convex portions 23 are opposed to each other. Since the area occupation ratio of the entire polishing layer 20 is 5% or more and 40% or less, it is possible to prevent the object to be polished from being damaged, and to polish the object to be polished. By the moderate elasticity of the polishing layer 20 and the effect of preventing damage, the polishing pad 1 can have an average particle diameter of the abrasive grains 22 of 2 μm or more and 45 μm or less, thereby simultaneously reducing the processing time and preventing the object to be polished. damage.

Further, since the shapes of the plurality of convex portions 23 are regularly arranged in a square pattern shape, the anisotropy of polishing can be reduced, and the surface to be polished can be easily flattened. Further, in the method for producing the polishing pad 1, since the polishing layer 20 can be formed by applying the composition for the polishing layer, the production efficiency is good.

[Other Embodiments] The present invention is not limited to the above-described embodiments, and various modifications and improvements can be made in addition to the above-described embodiments. In the above embodiment, the convex portions are formed in a lattice shape at equal intervals, and the intervals of the lattices may not be equally spaced, and for example, the intervals may be changed in the longitudinal direction and the lateral direction. However, when the interval between the convex portions is different, there is a problem that anisotropy occurs during polishing, and therefore it is preferable to be equally spaced. Further, the planar shape of the convex portion may not be a lattice shape, and may be, for example, a shape in which a polygon other than a quadrilateral is repeated, a circular shape, a shape having a plurality of parallel lines, or the like.

Further, in the above-described embodiment, the bottom surface of the plurality of groove portions is configured as a surface of the base material, and the depth of the groove portion may be smaller than the average thickness of the polishing layer, and the groove portion may not reach the surface of the base material. In this case, the depth of the groove portion may be 50% or more of the average thickness of the polishing layer. When the depth of the groove portion is less than the lower limit, the groove portion may be lost due to abrasion, and the durability of the polishing pad may be poor.

In the above-described embodiment, the method of forming the convex portion means a method using a mask. However, after coating the entire surface of the surface of the substrate, it may be formed by etching, laser processing, or the like. unit.

Further, as in the polishing pad 2 shown in FIG. 2, the support 40 laminated via the back surface layer 30 on the back side and the second adhesive layer 31 laminated on the back side of the support 40 may be provided. Since the polishing pad 2 is provided with the support 40, the operation of the polishing pad 2 becomes easy.

Examples of the material of the support 40 include thermoplastic resins such as polypropylene, polyethylene, polytetrafluoroethylene, and polyvinyl chloride, and engineering plastics such as polycarbonate, polyamide, and polyethylene terephthalate. (engineering plastic). By using such a material in the support 40, the support 40 has flexibility, and the polishing pad 2 follows the surface shape of the object to be polished, and the polished surface and the object to be polished become easily contacted, and thus processed. The efficiency is further improved.

The average thickness of the support 40 can be, for example, 0.5 mm or more and 2 mm or less. In the case where the average thickness of the support 40 is less than the lower limit, the strength of the support 40 is insufficient. On the other hand, when the average thickness of the support 40 exceeds the upper limit, it is difficult to attach the support 40 to the polishing apparatus or the flexibility of the support 40 is insufficient. [Examples]

Hereinafter, the present invention will be described in more detail by way of examples and comparative examples, but the invention is not limited to the following examples.

[Example 1] A diluent solvent (isophorone) and a curing agent ("Rikacid MH700" of Nippon Chemical and Chemical Co., Ltd.) and an appropriate amount of hardening were added to an epoxy resin ("JER1001" of Mitsubishi Chemical Corporation). The catalyst and the diamond abrasive grains ("LS series" of Lands Corporation, average particle diameter: 13 μm) were mixed, and the diamond abrasive grains were adjusted so that the content of the polishing layer was 50% by mass. Coating solution.

A PET film ("Melinex S" of Teijin Dupont Films Co., Ltd.) having an average thickness of 75 μm was used as a substrate, and a polishing layer was formed by coating on the surface of the substrate to prepare a polishing pad. Further, a convex portion is formed in the polishing layer by using a mask corresponding to the convex portion as a coating pattern. The convex portion was a square shape (area 1 mm ² ) having a side of 1 mm in plan view, and the average thickness was 135 μm. The convex portions are arranged in a regular pattern, and the area ratio of the convex portions to the entire polishing layer is set to 21%. Further, the D-type durometer hardness (HDD) of the adhesive using the epoxy resin, the hardener, and the curing catalyst was 75.

In addition, a rigid vinyl chloride resin sheet ("SP770" of Takiron Co., Ltd.) having an average thickness of 1 mm was used as a support for supporting the polishing pad to be fixed to the polishing apparatus, and an adhesive having an average thickness of 130 μm was used. The back surface of the substrate is bonded to the surface of the support. As the adhesive material, a two-sided tape ("5605HGD" of Sekisui Chemical Co., Ltd.) was used.

[Example 2 to Example 9, Example 16 to Example 21, Comparative Example 1 to Comparative Example 4, Comparative Example 7 to Comparative Example 9] The particle diameter of the diamond abrasive grains of Example 1 and the area of the convex portion The area occupancy rate was changed as shown in Table 1, and Example 2 to Example 9, Example 16 to Example 21, Comparative Example 1 to Comparative Example 4, and Comparative Example 7 to Comparative Example 9 were obtained. Further, the adhesives of Examples 2 to 9 and Examples 16 to 21, Comparative Examples 1 to 4, and Comparative Examples 7 to 9 had a D-type durometer hardness of 75.

[Example 10] A diluent solvent (isophorone) and a curing agent ("Rikacid HNA-100" of Nippon Chemical and Chemical Co., Ltd.) and an appropriate amount were added to an epoxy resin ("JER1001" of Mitsubishi Chemical Corporation). The hardening catalyst and the diamond abrasive grains ("LS series" of Lands Corporation, average particle diameter 13 μm) are mixed, and the diamond abrasive grains are adjusted so that the content of the polishing layer is 50% by mass. The coating liquid was obtained.

Example 10 was obtained in the same manner as in Example 1 except that the coating liquid was used. Further, the D-type durometer hardness of the adhesive using the epoxy resin, the hardener, and the curing catalyst was 80.

[Example 11] A diluent solvent (isophorone) and a curing agent ("Rikacid MH700" of Nippon Chemical and Chemical Co., Ltd.) and an appropriate amount of hardening were added to an epoxy resin ("JER1007" of Mitsubishi Chemical Corporation). The catalyst and the diamond abrasive grains ("LS series" of Lands Corporation, average particle diameter: 13 μm) were mixed, and the diamond abrasive grains were adjusted so that the content of the polishing layer was 50% by mass. Coating solution.

Example 11 was obtained in the same manner as in Example 1 except that the coating liquid was used. Further, the D-type durometer hardness of the adhesive using the epoxy resin, the hardener, and the curing catalyst was 65.

[Example 12] Example 12 was obtained by changing the area and area occupation ratio of the convex portion of Example 11 as shown in Table 1. Further, the adhesive of Example 12 had a D-type durometer hardness of 65.

[Example 13] A diluent solvent (isophorone), a curing agent ("YH306" of Mitsubishi Chemical Corporation), and an appropriate amount of hardening catalyst were added to an epoxy resin ("JER1001" of Mitsubishi Chemical Corporation). And diamond abrasive grains ("LS series" of Lands Corporation, average particle diameter: 13 μm) were mixed, and the diamond abrasive grains were adjusted so that the content of the polishing layer was 50% by mass. liquid.

Example 13 was obtained in the same manner as in Example 1 except that the coating liquid was used. Further, the D-type durometer hardness of the adhesive using the epoxy resin, the hardener, and the curing catalyst was 85.

[Example 14] Example 14 was obtained by changing the area and area occupation ratio of the convex portion of Example 13 as shown in Table 1. Further, the adhesive of Example 14 had a D-type durometer hardness of 85.

[Example 15] A diluent solvent (isophorone) and a curing agent ("Rikacid MH700" of Nippon Chemical and Chemical Co., Ltd.) and an appropriate amount of hardening were added to an epoxy resin ("JER1010" of Mitsubishi Chemical Corporation). The catalyst and the diamond abrasive grains ("LS series" of Lands Corporation, average particle diameter: 13 μm) were mixed, and the diamond abrasive grains were adjusted so that the content of the polishing layer was 50% by mass. Coating solution.

Example 15 was obtained in the same manner as in Example 1 except that the coating liquid was used. Further, the D-type durometer hardness of the adhesive using the epoxy resin, the hardener, and the curing catalyst was 61.

[Example 22] Example 22 was obtained in the same manner as in Example 8 except that the convex portion was a circular shape (area 3.14 mm ² ) having a diameter of 2 mm in plan view. Further, the adhesive of Example 22 had a D-type durometer hardness of 75.

[Example 23] A diluent solvent (isophorone) and a curing agent ("Rikacid MH700" of Nippon Chemical and Chemical Co., Ltd.) and an appropriate amount of hardening were added to an epoxy resin ("JER1001" of Mitsubishi Chemical Corporation). Catalyst, diamond abrasive grains as abrasive grains ("LS series" from Lands, average particle size 9 μm) and alumina filler ("Pacific 4000" from Pacific Rundum Co., Ltd. In the case where the content of the diamond abrasive grains to the polishing layer was 5% by mass and the content of the alumina filler was 60% by mass based on the polishing layer, a coating liquid was obtained.

An aluminum plate (A1050) having an average thickness of 300 μm was used as a substrate, and a polishing layer was formed by coating on the surface of the substrate to prepare a polishing pad. Further, a convex portion is formed in the polishing layer by using a mask corresponding to the convex portion as a coated pattern. The convex portion is set to one side of a square shape of 1.5 mm (area 2.25 mm ^2), and the average thickness is set to 200 μm in plan view. The convex portions are arranged in a regular pattern, and the area ratio of the convex portions to the entire polishing layer is set to 9%. Further, the D-type durometer hardness (HDD) of the adhesive using the epoxy resin, the hardener, and the curing catalyst was 85.

Further, the polishing pad was fixed to the support in the same manner as in Example 1 to obtain Example 23.

[Comparative Example 5] A diluent solvent (Dimethylformamide (DMF)) and diamond polishing were added to a thermoplastic polyurethane resin ("ET100" as a polyester-based TPU of NTW Co., Ltd.). The pellets ("LS series" of Lands, Inc., average particle diameter: 13 μm) were mixed, and the coating liquid was obtained so that the content of the diamond abrasive grains was 50% by mass based on the polishing layer.

Comparative Example 5 was obtained in the same manner as in Example 7 except that the coating liquid was used. Further, the D-type durometer hardness of the adhesive using the thermoplastic polyurethane resin was 30.

[Comparative Example 6] A diluent solvent (isophorone) and a curing agent ("Diethylethylamine" of Tokyo Chemical Industry Co., Ltd.) were added to an epoxy resin ("JER828" of Mitsubishi Chemical Corporation). An appropriate amount of hardening catalyst and diamond abrasive grains (Lands' "LS series", average particle size 13 μm) are mixed, and the content of the diamond abrasive grains with respect to the polishing layer is 50% by mass. Adjustment was made to obtain a coating liquid.

Comparative Example 6 was obtained in the same manner as in Example 7 except that the coating liquid was used. Further, the D-type durometer hardness of the adhesive using the epoxy resin, the hardener, and the curing catalyst was 91.

[Polishing Conditions] Using the polishing pads obtained in the above-described Examples 1 to 23 and Comparative Examples 1 to 9, the glass substrate was polished. The glass substrate was a soda lime glass (manufactured by Hiraoka Special Glass Co., Ltd.) having a diameter of 6.25 cm and a specific gravity of 2.4. The polishing was carried out using a commercially available double side grinding machine ("EJD-5B-3W" of Engis Japan Co., Ltd.). The carrier of the double side grinder is an epoxy glass having a thickness of 0.6 mm. The polishing was carried out by setting the polishing pressure to 200 g/cm ² for 15 minutes under the conditions of an upper platen rotation number of 60 rpm, a lower platen rotation number of 90 rpm, and a sun gear rotation number of 30 rpm. At this time, as a coolant, "Toolmate GR-20" of Moresco Co., Ltd. was supplied to 120 cc per minute.

[Evaluation Method] The glass substrates polished using the polishing pads of Examples 1 to 23 and Comparative Examples 1 to 9 were subjected to the following evaluations.

<Polishing Rate> The polishing rate was calculated by dividing the weight change (g) of the glass substrate before and after polishing by the surface area (cm ² ) of the glass substrate, the specific gravity (g/cm ³ ) of the glass substrate, and the polishing time (minutes). The results are shown in Table 1.

<Finishing roughness> For the finishing roughness, a contact surface roughness meter ("S-3000" from Mitutoyo Co., Ltd.) was used to measure any four parts on the front and back sides. The average of 8 parts is totaled. The results are shown in Table 1.

<Drying layer durability> With respect to the durability of the polishing layer, the state of the polished layer after polishing was observed, and evaluation was performed in three levels according to the following criteria. The results are shown in Table 1.

(Criteria for Durability of Polishing Layer) A: The polishing layer under visual observation was not confirmed to have good durability. B: It was confirmed that the polishing layer was visually abraded and the durability was slightly inferior. C: The abrasion of the polishing layer (total abrasion) was confirmed and the durability was poor.

<Polishing performance> The polishing rate and the finishing roughness were comprehensively judged, and evaluation was performed in three levels according to the following criteria. The results are shown in Table 1.

(Criteria for polishing performance) A: The balance between the polishing rate and the finishing roughness is excellent, and the polishing can be performed satisfactorily. B: The balance between the grinding rate and the finishing roughness is poor but grindable. C: A defect in the substrate was generated or the polishing rate was not exhibited and the polishing was impossible.

[Table 1]

In the table, "unable to grind" means that polishing cannot be performed due to peeling of the polishing layer, and thus the polishing rate or finishing roughness (Ra) cannot be measured. In addition, the term "cracking" means that the polishing film has a missing edge, a crack, or the like, and the polishing rate or the finishing roughness (Ra) cannot be measured. Further, the term "wearing" means that the polishing layer is worn early, so that the polishing rate or the finishing roughness (Ra) cannot be measured.

According to Table 1, the average particle diameter of the abrasive grains is 2 μm or more and 45 μm or less, and the D-type durometer hardness of the adhesive is 60 or more and 88 or less, and the average area of the convex portions on the surface of the polishing layer is 0.5 mm ² or more. and 13 mm ² or less, and the convex portion with respect to the occupancy area of the entire polishing layer is 5% to 40% of Example 1 to Example 23, the polishing rate to be polished and finished roughness is excellent, The durability of the polishing layer is high, and the glass substrate can be polished well.

On the other hand, in Comparative Example 1 and Comparative Example 2 in which the average area of the convex portions was less than 0.5 mm ² , the polishing layer was peeled off and was not polished. On the other hand, in Comparative Example 7 in which the average area of the convex portions exceeded 13 mm ² , it was considered that the frictional resistance during polishing of the polishing pad was increased, and the glass substrate was damaged, and polishing was not performed satisfactorily.

Further, in Comparative Example 8 in which the area ratio of the convex portion was less than 5%, the abrasion due to the peeling of the convex portion of the polishing layer progressed, and the durability was low. On the other hand, in Comparative Example 3 in which the area occupation ratio of the convex portion exceeded 40%, it was considered that the frictional resistance during polishing of the polishing pad was increased, and the glass substrate was damaged, and the polishing could not be performed satisfactorily.

Further, in Comparative Example 4 in which the average particle diameter of the abrasive grains was less than 2 μm, the polishing force was insufficient and polishing was impossible. On the other hand, in Comparative Example 9 in which the average particle diameter of the abrasive grains exceeded 45 μm, the polishing layer was worn early and the durability was low.

Further, in Comparative Example 5 in which the hardness of the D-type durometer was less than 60, it was considered that the polishing force due to the large deformation of the polishing layer was insufficient and polishing was impossible. On the other hand, in Comparative Example 6 in which the hardness of the D-type durometer was more than 88, it was considered that the edge was not broken due to the hardening of the polishing layer or cracking, and the polishing was not performed satisfactorily.

In more detail, when the first, first, tenth, and eleventh examples in which the hardness of the D-type durometer is different are compared, the D-type durometer hardness is 70 or more and 80 or less. The polishing rates of 1 and 10 were higher than those of Example 11 and Example 15. From this, it is understood that the hardness of the D-type durometer is more preferably 70 or more and 80 or less.

Further, when Example 1, Example 2, Example 4, Example 6, and Example 16 to Example 18 in which only the average area of the convex portions is different, the average area of the convex portions is 4 mm ^{2 .} The polishing rate of Example 6 above and 8 mm ² or less was higher than the other examples. From this, it is understood that the average area of the convex portions is more preferably 4 mm ² or more and 8 mm ² or less.

Further, when Example 1, Example 8, and Example 9 in which only the average particle diameter of the abrasive grains were different were compared, the finishing roughness was relatively low. On the other hand, in Example 1 and Example 8 in which the average particle diameter of the abrasive grains was 5 μm or more, the polishing rate was higher than that in Example 9, and the polishing rate of Example 1 in which the average particle diameter of the abrasive grains was 10 μm or more was particularly high. . Further, when Example 7 and Example 19 to Example 21 in which only the average particle diameter of the abrasive grains were different were compared, the polishing rate was relatively high. On the other hand, Example 7 in which the average particle diameter of the abrasive grains is 20 μm or less, the finishing roughness (Ra) of Example 19 and Example 20 is low, and the average particle diameter of the abrasive grains is 15 μm or less. The finishing roughness (Ra) of Example 19 was particularly low. From this, it is more preferable that the average particle diameter is 5 μm or more and 20 μm or less, and it is more preferable to set the average particle diameter to 10 μm or more and 15 μm or less. [Industrial availability]

According to the polishing pad of the present invention, it is possible to simultaneously shorten the processing time of the glass substrate or the like and prevent damage of the object to be polished. Therefore, the polishing pad can be preferably used for processing of a substrate or the like of an electronic device.

1, 2‧‧‧ polishing pad
10‧‧‧Substrate
20‧‧‧Abrasive layer
21‧‧‧Binder
22‧‧‧ abrasive grain
23‧‧‧ convex
30‧‧‧Next layer
31‧‧‧second second layer
40‧‧‧Support

Fig. 1A is a schematic plan view showing a polishing pad according to an embodiment of the present invention. Fig. 1B is a schematic end view taken along line A-A of Fig. 1A. Fig. 2 is a schematic end view showing a polishing pad of a different embodiment from Fig. 1B.

1‧‧‧ polishing pad

10‧‧‧Substrate

20‧‧‧Abrasive layer

21‧‧‧Binder

22‧‧‧ abrasive grain

23‧‧‧ convex

30‧‧‧Next layer

Claims (7)

A polishing pad comprising a substrate and a polishing layer laminated on a surface side thereof, wherein the polishing layer has a resin binder and abrasive grains dispersed in the binder, The abrasive grains have an average particle diameter of 2 μm or more and 45 μm or less, and the D-type durometer hardness of the adhesive is 60 or more and 88 or less. The polishing layer has a plurality of convex portions on the surface, and the convex portion The average area is 0.5 mm ² or more and 13 mm ² or less, and the area ratio of the plurality of convex portions to the entire polishing layer is 5% or more and 40% or less. The polishing pad of claim 1, wherein the abrasive particles are diamond abrasive grains. The polishing pad according to Item 1 or 2, wherein the composition constituting the binder contains a thermosetting epoxy resin as a main component. The polishing pad of claim 1 or 2, wherein the plurality of convex portions are regularly arranged. The polishing pad according to claim 1 or 2, wherein the substrate has an adhesive layer on the back side of the substrate. The polishing pad of claim 5, wherein the adhesive layer is composed of an adhesive. A method for producing a polishing pad, comprising: a substrate; and a polishing pad having a polishing layer laminated on a surface side thereof, comprising: forming the polishing layer by coating a composition for a polishing layer; In the step, the polishing layer composition has a resin binder component and abrasive grains, and the abrasive grains have an average particle diameter of 2 μm or more and 45 μm or less, and the D-type hardness of the binder component after curing The hardness is 60 or more and 88 or less. In the polishing layer step, an average area of 0.5 mm ² or more and 13 mm ² or less and an area occupation ratio with respect to the entire polishing layer is formed on the surface of the polishing layer. 5% or more and 40% or less of the convex portion.