JPH10249709A - Polishing cloth - Google Patents

Abstract

(57) [Problem] To improve the quality of a polishing cloth used for precision polishing of a semiconductor substrate and a hard disk substrate. SOLUTION: The urethane resin film (1) having a vertical foam structure has a hardness different from the hardness of the urethane resin film (1) in the range of 3 to 15 degrees in Shore hardness. A polishing cloth obtained by bonding (3) via an adhesive (2).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a polishing cloth used for precision polishing of semiconductor substrates such as silicon and hard disk substrates.

[0002]

2. Description of the Related Art Conventionally, a polishing cloth used for precision polishing of a semiconductor substrate such as metallic silicon or gallium arsenide, or a hard disk substrate such as aluminum / nickel glass has a urethane resin film having a vertical foam structure on one surface of a nonwoven fabric. The formed polishing cloth is used.

[0003]

As described above, in a polishing cloth having a non-woven fabric as a base material and a polyurethane resin layer having a vertical foam structure formed on one surface thereof, the thickness, density, hardness,
The compression ratio and the compression elasticity vary greatly, and these variations in quality directly affect the quality of the polishing cloth, and have a disadvantage that the polishing performance varies.

[0004] In addition, variations in the thickness and density of the nonwoven fabric affect the processing accuracy when forming a urethane resin film having a vertical foam structure, which is a factor that causes the thickness and structure of the vertical urethane foam resin film to fluctuate. .

[0005] Further, since the nonwoven fabric is an aggregate of fibers, dust is often generated from a cut surface or the like, which has been a factor of causing troubles such as polishing scratches due to the dust.

The present invention provides a polishing cloth having uniform quality without variation in polishing performance and generating no dust.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a urethane resin film (1) having a vertical foam structure with a Shore hardness higher than that of the urethane resin film (1) having a vertical foam structure. Then, a resin film (3) having a difference in hardness within a range of 3 degrees or more and 15 degrees or less was bonded by an adhesive (2).

In the polishing cloth of the second invention, the resin film (3) is a sponge-structured porous resin film (3A). (Fig. 2)

The third invention has a compression elastic modulus of 30% or more and 95% or more.
% Of the resin film (3).

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A urethane resin film (1) having a vertical foam structure having a function of holding a polishing slurry is formed by uniformly applying a urethane resin liquid to one surface of a flat sheet-like base material such as a film or a filament fabric, and wet-solidifying. It is manufactured by buffing after coagulation, desolvation, drying after solidification by the method.Thickness and foam structure are very uniform, so physical quality such as hardness, compressibility, compression elastic modulus and opening diameter A uniform urethane resin film with a vertical foam structure without variation can be obtained.

Since the resin film (3) is a resin film formed of a natural or synthetic resin such as an acrylic resin, a urethane resin, a synthetic rubber, a natural rubber, etc., the resin film (3) is very homogeneous, and has a thickness, hardness, compressibility, and compressibility. Variations in physical properties such as elastic modulus are very low.

The above-mentioned urethane resin film (1) having a very uniform vertical foam structure and a uniform resin film (3) containing no fibers or the like are bonded to an adhesive mainly composed of acrylic resin, epoxy resin, urethane resin or the like. (2) to provide a polishing cloth of stable quality with very little variation in physical properties related to polishing performance such as thickness, density, compression ratio, compression elastic modulus, opening diameter, etc. Can be done.

Since the resin film (3) is different in hardness from 3 degrees to 15 degrees in Shore hardness than the hardness of the urethane resin film (1) having the vertical foam structure, various polishing methods are employed. The most suitable polishing cloth can be designed for the conditions.

The resin film (3) having a sponge structure of the second invention
In A), a sponge structure resin film obtained by independently foaming or continuously foaming a polyurethane resin, a polyacrylic resin, a polypropylene resin, a synthetic rubber, or a natural rubber by a dry foaming method or a wet coagulation method is obtained. (Fig. 2)

The compression modulus of the third invention is 30% or more and 95% or more.
% Or less can be adjusted by selecting the type of resin, the degree of crosslinking, and the degree of vulcanization.

[0016]

【Example】

Example 1 One side of a 75 micron thick polyester film was previously coated with 15% ether urethane resin, N, N
-Dimethylformamide (hereinafter referred to as DMF) 83.9
A resin solution prepared to 5%, pigment 1% and activator 0.05% was applied by knife over roll method, immediately immersed in water, completely coagulated, washed with water, removed from DMF, dried, and then placed on a belt sander. To grind the skin layer of the urethane resin film, and then peel it off from the polyester film.
Thus, a urethane resin film (1) having a vertical foam structure was obtained.

On the other hand, an ethylene-vinyl acetate copolymer (hereinafter referred to as EVA) was extruded into a sheet by an extruder to obtain a uniform sheet (3) having a thickness of 0.9 mm and a Shore hardness of 70 degrees. One side of this eversheet (3) was coated with a chloroprene rubber adhesive (2) by a knife over roll method and dried, and then the above-mentioned urethane resin film (1) having a vertical foam structure was pressure-bonded to obtain a polishing cloth. As a result of measuring the quality of the polishing cloth, the thickness, hardness, compression ratio, and compression elasticity variation were extremely small compared to the polishing cloth based on nonwoven fabric, and the vertical foam structure of the urethane resin film was uniform and open. No variation in caliber was observed. Further, no dust was generated from the cut surface, and no generation of polishing scratches due to the dust was observed.

Example 2 A polyurethane foam produced by reacting polyether triol and tolylene diisocyanate was sliced, and had a thickness of 0.95 mm, a hardness of 50 degrees, a compressibility of 12% and a compressive elasticity of 85%. A resin film (3A) having a sponge structure was obtained. After applying a curable urethane adhesive solution to the film surface of the urethane resin film (1) having a vertical foam structure produced in Example 1 with a spray coater and drying,
The resin film (3) having the above-mentioned sponge structure is laminated,
After curing for 8 hours and bonding, a polishing cloth was obtained. Using this polishing cloth, the silicon wafer was polished at a low pressure. As a result, a polishing result with extremely excellent flatness, which could not be obtained with a conventional polishing cloth made of a nonwoven fabric substrate, could be obtained.

Example 3 Fineness 50 denier, woven density,
A polyester long-fiber woven fabric having a warp of 112 fibers / inch and a weft of 98 fibers / inch is subjected to refining, fluorine treatment and heat setting treatment on one side of a base material in advance, urethane resin 16%, DMF 83%,
A resin solution prepared with 0.995% pigment and 0.005% activator was applied by knife over roll method, immediately immersed in water, solidified, washed and dried, and the skin of the formed urethane resin film was belted. After grinding with a sander, the film was peeled off from the substrate to obtain a urethane resin film (1) having a vertical foam structure with a Shore hardness of 68 degrees.

The polypropylene foam produced by radiation crosslinking was sliced to a thickness of 0.6 mm to obtain a resin film (3A) having a sponge structure having a Shore hardness of 60 degrees, a compressibility of 6% and a compressive elasticity of 55%. . A chloroprene-based adhesive (2) was applied to one surface of the resin film (3A) having a sponge structure by a knife over roll and dried, and then the urethane resin film having a vertical foam structure was attached to obtain a polishing cloth. As a result of polishing the aluminum / nickel substrate, which is a substrate for a hard disk, using this polishing cloth, a polishing result excellent in flatness without polishing scratches was obtained.

[0021]

The polishing cloth according to the present invention has a very small variation in physical properties such as thickness, density, hardness, compressibility, compressive modulus and the like, and has a uniform vertical foam structure, so that it is uniform and stable. Exhibits a polishing effect. The hardness of the resin film (3) as the base material and the urethane resin film (1) of the vertical foam structure holding the polishing slurry differ from Shore hardness of 3 degrees to 15 degrees, so that it can be used in a wide range of polishing conditions. Can respond.
Further, since the dust generation is very low, it is possible to prevent the occurrence of polishing scratches.

The polishing cloth according to the second aspect of the present invention can change physical properties such as density, hardness, compression ratio, compression elastic modulus and the like in a wide range, and can cope with a wide range of polishing conditions.

The polishing cloth according to the third aspect of the present invention prevents the polishing surface from being distorted due to the distortion of the polishing material and exhibits a stable polishing effect.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a polishing cloth according to an embodiment of the present invention.

FIG. 2 is a sectional view of a polishing pad according to Embodiment 2 of the present invention.

[Explanation of symbols]

 1 Urethane resin film with vertical foam structure 2 Adhesive 3,3A resin film

Claims (3)

[Claims] 1. A resin film (3) having a hardness different from the hardness of the urethane resin film (1) in a range of 3 to 15 degrees in Shore hardness in a urethane resin film (1) having a vertical foam structure. ) Is bonded via an adhesive (2). 2. The polishing cloth according to claim 1, wherein the resin film is a porous resin film having a sponge structure. 3. The polishing cloth according to claim 1, wherein the polishing pad is a resin film (3) having a compression elastic modulus of 30% or more and 95% or less.