JP2017022254A - Abrasive pad and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an abrasive pad capable of flattening a processing surface and accelerating a polishing speed in a chemical mechanical polishing of a silicon carbide substrate.SOLUTION: The abrasive pad is used for chemical mechanical polishing of a silicon carbide substrate. The abrasive pad includes: a first abrasive material 10 including artificial leather and a polymer elastic body immersed in the artificial leather; and a second abrasive material 20 which is composed of an adhesive for adhering the first abrasive materials 10 with each other and of which the hardness is higher than that of the first abrasive material 10. On an abrasive surface 30 of the abrasive pad, abrasive surfaces of the first abrasive materials 10 and abrasive surfaces of the second abrasive materials 20 are disposed alternately.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a polishing pad used for chemical mechanical polishing and a method for manufacturing the same, and more particularly to a polishing pad suitable for chemical mechanical polishing of a silicon carbide substrate and a method for manufacturing the same.

  Conventionally, a workpiece held on a carrier is brought into contact with a polishing surface of a polishing pad affixed on a surface plate, and the carrier and the surface plate are simultaneously rotated while flowing slurry on the polishing surface to polish the workpiece. Performing chemical mechanical polishing is known.

  This chemical mechanical polishing is used for polishing a silicon carbide substrate. However, since silicon carbide is a stable crystal that is very hard and has a very high melting point, it is a machine that uses solid components (abrasive grains) in the slurry. It was difficult to polish the silicon surface with high efficiency even when the interaction between the chemical action and the chemical action of the liquid component in the slurry was used.

  For example, Patent Document 1 below discloses an example in which a silicon carbide substrate is polished by chemical mechanical polishing, but the polishing rate is lower than 150 nm / hour.

  As a polishing pad used for chemical mechanical polishing, a polishing pad made of artificial leather is known. For example, Patent Document 2 below discloses a polishing pad made of artificial leather including a nonwoven fabric and a polymer elastic body impregnated in the nonwoven fabric.

  Artificial leather is generally low in rigidity, flexible, and has a smooth surface. Therefore, in order to apply artificial leather as a polishing pad, as described in Patent Document 2 below, in order to impart mechanical frictional force and polishing force to the polishing surface of the polishing pad, fibers on the polishing surface are used. It was necessary to perform a raising process.

  When a conventional polishing pad made of artificial leather is applied to chemical mechanical polishing of a silicon carbide substrate, there is an advantage that scratches are hardly generated on the processed surface because the polishing pad is flexible. However, since the polishing pad has low rigidity, it is difficult to obtain a flat surface and the polishing rate is low.

  As a method for increasing the hardness of a polishing pad made of artificial leather, press working for compressing artificial leather is known (see Patent Document 3 below). However, there is a problem in that the retention performance of the slurry is lowered because the space inside the pad is reduced or reduced by compressing the artificial leather. Therefore, in chemical mechanical polishing of a silicon carbide substrate, it has been difficult to improve the flatness of the processed surface and the polishing rate simply by increasing the rigidity of the polishing pad.

Japanese Patent Laying-Open No. 2015-084432 JP 2012-214944 A JP 2008-302454 A

  The problem to be solved by the present invention is to provide a polishing pad capable of improving the flatness and polishing rate of a processed surface and the manufacturing method thereof in chemical mechanical polishing of a silicon carbide substrate.

In order to solve the above problems, the present invention provides the following polishing pad and a method for producing the same.
1. A polishing pad used for chemical mechanical polishing of a silicon carbide substrate,
A first abrasive comprising an artificial leather and a polymer elastic body impregnated in the artificial leather;
It consists of an adhesive that bonds the first abrasives together, and includes a second abrasive that has higher hardness than the first abrasives,
A polishing pad, wherein the polishing surface of the first polishing material and the polishing surface of the second polishing material are alternately arranged on the polishing surface of the polishing pad.
2. 2. The polishing pad according to 1 above, wherein the polishing surface of the first abrasive is a cut surface that intersects the surface of the artificial leather.
3. The polishing pad according to 1 above, wherein the hardness of the first abrasive is in the range of ASKER C 75-85.
4). 2. The polishing pad according to 1 above, wherein the hardness of the second abrasive is in the range of ASKER C 90-98.
5. 2. The polishing pad according to 1 above, wherein the distance between the second abrasives is in the range of 0.5 mm to 5.0 mm.
6). A method of manufacturing a polishing pad used for chemical mechanical polishing of a silicon carbide substrate,
Cutting artificial leather to form multiple primary materials,
Each primary material is impregnated with a polymer elastic body to form a plurality of secondary materials,
Applying an adhesive to the surface and / or back of each secondary material, and bonding the secondary materials with the adhesive to form a laminate,
A method comprising a step of cutting the laminated body to form a polished surface having a cut surface in which a first layer made of a secondary material and a second layer made of the adhesive are alternately arranged.

  According to the present invention, the polishing surface of the first polishing material and the polishing surface of the second polishing material having higher hardness than the first polishing material are alternately arranged on the polishing surface of the polishing pad. Due to the interaction between the abrasive and the second abrasive, the flatness of the processed surface and the polishing rate can be improved while suppressing the generation of scratches. Further, according to the present invention, since the first abrasive material includes a polymer elastic body impregnated in artificial leather, the hardness suitable for the polishing process of the silicon carbide substrate can be obtained without deteriorating the slurry holding performance. It is possible. Furthermore, according to the present invention, since the polishing surface of the first abrasive is a cut surface that intersects the surface of the artificial leather, there are a lot of fibers exposed to the polishing surface. It is possible to improve the power. In addition, the polished surface having such a cut surface has an advantage that the fibers of the artificial leather are raised appropriately, so that it is not necessary to perform the raising treatment.

FIG. 1 is a perspective view of an embodiment of the present invention. FIG. 2 is a schematic partial sectional view of an embodiment of the present invention. FIG. 3 is a photomicrograph of the cut surface of the secondary material when the laminate is cut substantially parallel to the surface of the secondary material (the surface side of the artificial leather). FIG. 4 is a photomicrograph of the cut surface of the secondary material (the polished surface of the first abrasive) when the laminate is cut substantially perpendicular to the surface of the secondary material (the surface side of the artificial leather). . FIG. 5 is a diagram for explaining the manufacturing method of the embodiment of the present invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawings. However, the technical scope of the present invention is not limited to the contents of the following description.

  As shown in FIG. 1, the polishing pad according to the present invention includes a first abrasive 10 and a second abrasive 20.

  The first abrasive 10 includes artificial leather and a polymer elastic body impregnated in the artificial leather.

  Artificial leather is obtained by impregnating a non-woven fabric made of synthetic fibers such as nylon fibers with a synthetic resin such as polyurethane. A commercially available artificial leather can be used, and the structure of the artificial leather is not particularly limited. It is preferable to employ an artificial leather having more voids inside. The hardness of the artificial leather is preferably in the range of ASKER C 60-70, and more preferably in the range of ASKER C 62-68.

  The polymer elastic body is impregnated in artificial leather in order to increase the hardness of the first abrasive 10. The polymer elastic body is applied to the voids inside the artificial leather, but is impregnated into the artificial leather so that the voids remain after the application. Specific examples of the polymer elastic body include, but are not limited to, polyurethane elastomers.

  The hardness of the first abrasive 10 impregnated with the polymer elastic body is preferably in the range of ASKER C 75 to 85, and more preferably in the range of ASKER C 77 to 83. When the hardness of the first abrasive 10 is lower than ASKER C 75, the polishing efficiency is lowered. On the other hand, when the hardness is higher than ASKER C 85, scratches are likely to occur.

  It is preferable to employ a polymer elastic body that exhibits resistance to the liquid component contained in the slurry. By impregnating the artificial leather with the polymer elastic body, the synthetic resin impregnated in the nonwoven fabric is coated with the polymer elastic body. Therefore, even if the synthetic resin impregnated in the nonwoven fabric does not show resistance to the liquid component contained in the slurry by impregnating the artificial leather with a polymer elastic body having chemical resistance, the first abrasive 10 It becomes possible to improve the chemical resistance.

  The second abrasive 20 is obtained by curing an adhesive. Specific examples of the adhesive that is the base material of the second abrasive 20 include, but are not limited to, urethane adhesives. The hardness of the second abrasive 20 is preferably in the range of ASKER C 90-98, and more preferably in the range of ASKER C 92-96.

  The first abrasive 10 and the second abrasive 20 are alternately arranged on the polishing surface 30 of the polishing pad. The width (thickness) of the second abrasive 20 is in the range of 40 μm to 300 μm, but is not limited thereto. The interval between the second abrasives 20 (this interval is substantially equal to the width (thickness) of the first abrasive 10) is preferably in the range of 0.5 mm to 5.0 mm. More preferably, it is in the range of 5 mm to 3.0 mm, and most preferably in the range of 0.5 mm to 1.5 mm. As this interval is narrower, the polishing rate tends to be improved.

  The polished surface of the first abrasive 10 is preferably a cut surface that intersects the surface of the artificial leather. This cut surface is a cross section that appears when the artificial leather is cut so as to cut vertically between the front and back surfaces of the artificial leather.

  Cutting the secondary material when cutting the laminated body, which will be described later, approximately parallel to the surface of the artificial leather (primary material) impregnated with an elastic polymer (secondary material) (surface side of the artificial leather) Since not only the synthetic resin impregnated in the nonwoven fabric but also the polymer elastic body impregnated in the artificial leather is deposited on the surface, there are few fibers exposed to the cut surface, and the fiber reaches the surface. They are lying down (see Fig. 3).

  On the other hand, as shown in FIG. 4, the cut surface has a large amount of fibers exposed to the surface, and the fibers are raised, so that the mechanical frictional force and polishing force can be improved. And is suitable as a polished surface. In addition, as shown in FIG. 4, there are more voids that can effectively hold the slurry, as shown in FIG. 4, and thus the slurry holding performance can be improved.

  In the polishing pad according to the present invention, the first abrasive 10 has a lower hardness than the second abrasive 20, and more fibers are exposed on the polishing surface 30, so that the processed surface is mainly smooth, It is thought that the polishing surface which suppresses generation | occurrence | production of a scratch is exerted on the processed surface. On the other hand, since the second abrasive 20 has a higher hardness than the first abrasive 10, it is considered that the second abrasive 20 mainly exerts a sharpening action on the machined surface on the machined surface. As will be described later, the polishing pad according to the present invention has scratches caused by the interaction between the polishing surfaces of the first polishing material 10 and the polishing surface of the second polishing material 20 alternately arranged on the polishing surface 30. It is possible to significantly improve the flatness and polishing rate of the processed surface as compared with the prior art while suppressing the occurrence.

  On the polishing surface 30 of the polishing pad, a groove 40 is formed for spreading the slurry over the entire polishing surface 30 (see FIGS. 1 and 2). A double-sided tape 50 for fixing the polishing pad to the surface plate of the polishing apparatus is provided on the back side of the polishing pad (see FIGS. 1 and 2).

  Next, an example of a method for manufacturing a polishing pad according to the present invention will be described.

(1) Formation of primary material First, a plurality of primary materials are formed by cutting artificial leather as a raw material (see FIG. 5). The primary material is a cut piece of artificial leather. In this step, the artificial leather is cut so as to cut vertically between the front and back surfaces of the artificial leather, which is a raw material.

(2) Formation of Secondary Material Next, the primary material is impregnated with a polymer elastic body to form a plurality of secondary materials (see FIG. 5). The secondary material is obtained by impregnating a cut piece of artificial leather with a polymer elastic body. In this step, for example, the secondary material is formed by immersing the primary material in a polyurethane-based elastomer solution and then coagulating the elastomer. According to this method, the hardness of the first abrasive 10 can be increased without compressing the artificial leather. Therefore, since the first abrasive 10 manufactured by this method has more or larger voids left inside than the one manufactured by the method of compressing artificial leather, the slurry holding performance is high.

(3) Formation of Laminate Next, an adhesive is applied to each of the front and / or back surfaces of a plurality of secondary materials, and the secondary materials are bonded together with the adhesive to form a laminate (FIG. 5). reference). The laminate may be pressurized to increase the adhesive strength.

(4) Formation of tertiary material having polished surface Next, the laminate is cut to form a tertiary material having the polished surface 30 formed of the cut surface. At this time, the laminate is cut so that the layer made of the secondary material (first abrasive 10) and the layer made of the adhesive (second abrasive 20) are alternately arranged on the polishing surface 30. . By cutting the laminate in this manner, the polishing surface 30 has the polishing surface of the first abrasive 10 and the polishing surface of the second abrasive 20. Double-sided tape 50 is affixed to the back surface of the tertiary material (the surface opposite to the polishing surface 30).

(5) Formation of Groove Next, the groove 40 is formed on the polishing surface 30 of the tertiary material. The groove 40 can be formed by pressing or cutting.

(6) Molding Finally, the tertiary material is molded into a circular shape by pressing or the like to complete the polishing pad.

  The Example of this invention was manufactured with the above-described manufacturing method. In addition, the brand name "Clarino (registered trademark)" (available from Kuraray Co., Ltd.) was used as the artificial leather. The hardness of this artificial leather was ASKER C 65 (average value).

  The hardness of the first abrasive 10 of the example was ASKER C 79 (average value), and the hardness of the second abrasive 20 was ASKER C 94 (average value). The spacing between the second abrasives 20 was 1.15 mm in Example 1 and 2.3 mm in Example 2.

An example having a diameter of 810 mm was attached to a surface plate of a polishing apparatus (32SP AW (single-side polishing apparatus) manufactured by Speedfam Co., Ltd.) with a double-sided tape 50 and chemical mechanical polishing was performed. The workpiece is a 3 inch (76.2 mm) diameter silicon carbide (4H—SiC) substrate. The processed surface is a silicon surface. The rotation speed of the surface plate and the carrier was set to 50 rpm, and the pressure was set to 715 g / cm ² (about 70 kPa). A slurry containing colloidal silica as abrasive grains was used. The slurry flow rate was 50 mL per minute. The results are shown in Table 1.

  As shown in Table 1, in the chemical mechanical polishing using Examples 1 and 2, the polishing rate was twice or more that of the prior art. Also, the surface roughness (Ra) was very good at less than 0.05 nm, and high flatness was obtained. When the processed surface was observed with an optical microscope after processing, no scratch was found.

  The polishing pad according to the present invention can be suitably used not only for silicon carbide substrates but also for chemical mechanical polishing of sapphire substrates, gallium nitride substrates, and the like.

DESCRIPTION OF SYMBOLS 10 1st abrasive material 20 2nd abrasive material 30 Polishing surface of polishing pad 40 Groove 50 Double-sided tape

Claims (6)

A polishing pad used for chemical mechanical polishing of a silicon carbide substrate,
A first abrasive comprising an artificial leather and a polymer elastic body impregnated in the artificial leather;
It consists of an adhesive that bonds the first abrasives together, and includes a second abrasive that has higher hardness than the first abrasives,
A polishing pad, wherein the polishing surface of the first polishing material and the polishing surface of the second polishing material are alternately arranged on the polishing surface of the polishing pad.   The polishing pad according to claim 1, wherein the polishing surface of the first abrasive is a cut surface that intersects the surface of the artificial leather.   The polishing pad according to claim 1, wherein the hardness of the first abrasive is in the range of ASKER C 75-85.   The polishing pad according to claim 1, wherein the hardness of the second abrasive is in the range of ASKER C 90-98.   The polishing pad according to claim 1, wherein an interval between the second abrasives is in a range of 0.5 mm to 5.0 mm. A method of manufacturing a polishing pad used for chemical mechanical polishing of a silicon carbide substrate,
Cutting artificial leather to form multiple primary materials,
Each primary material is impregnated with a polymer elastic body to form a plurality of secondary materials,
Applying an adhesive to the surface and / or back of each secondary material, and bonding the secondary materials with the adhesive to form a laminate,
A method comprising a step of cutting the laminated body to form a polished surface having a cut surface in which a first layer made of a secondary material and a second layer made of the adhesive are alternately arranged.

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