JPH10146754A - Polishing template material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of abrasion powder such as damaging a workpiece by using polyarylate fiber as a base material, and forming a hardening agent of thermosetting resin as a matrix. SOLUTION: It is desirable that a totally aromatic polyester by copolymerizing a hydroxynaphthoic acid and a hydroxybenzoic acid be used as polyarylate fiber being a base material. A hardening accelerator is blended according to its necessity to promote hardening reaction of epoxy resin and a phenol added conjugate diene type polymer. These components becoming a matrix of a polishing template material are dissolved in a solvent, and are formed as varnish, and are impregnated into a base material, and are dried, and are formed as a prepreg. Tensile ductility of polyarylate fiber nonwoven fabric is 0.5 to 2,0%, and (base material directional tensile ductility/base material orthogonal directional tensile ductility) is (1 to 2)/(2 to 3).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing template material.

[0002]

2. Description of the Related Art High precision wafers for semiconductor manufacturing, aluminum plates for magnetic disks, glass panels for flat panel displays, carbon plates for semiconductor manufacturing equipment or magnetic disks, glass plates for semiconductor manufacturing equipment or magnetic disks, etc. Flatness is required. A polishing process is indispensable for the production of those requiring high precision flatness. In particular, electronic device members typified by semiconductor manufacturing wafers require processing accuracy on the order of 1 μm.

[0003] In the production process of silicon wafers for semiconductor production, the most frequently used practically is a constant pressure sliding mechanical chemical polishing method. In this method, a silicon wafer is pressed against a rotating table on which a polishing cloth is stuck with a constant load, and a polishing agent in which fine abrasive grains for mechanical removal and a chemical solution for etching are mixed is supplied and polishing is performed. is there. SiO ₂ particles are used as fine abrasive grains. An alkali hydroxide aqueous solution is used as the chemical liquid. Further, as the abrasive grains, using particles that are softer than the workpiece and can cause a chemical reaction with the workpiece,
Mechanochemical polishing methods have also been used. As abrasive grains, carbonate particles such as BaCO ₃ and CaCO ₃ are considered to be effective in polishing a silicon wafer. According to the mechanochemical polishing method, since SiO ₂ particles having an indentation or scratching effect on silicon are not used,
A surface free of a work-affected layer is obtained.

In these polishing methods, a workpiece is placed on a polishing board by a polishing template (hereinafter referred to as a template).
And adsorb or adhere to the template using water or wax as a medium. The template needs to have good thickness accuracy and be resistant to a chemical solution of an abrasive, particularly an alkaline aqueous solution. Conventionally, a glass cloth base epoxy resin laminate has been most often used. This is because chemical resistance, rigidity, dimensional accuracy, and the like are more suitable for the above-mentioned applications than paper-based phenolic resin laminates and glass nonwoven epoxy resin laminates.

[0005]

However, when a glass cloth-based epoxy resin laminate obtained by molding is used as a template and is machined by a die-punching process or the like, the wall surface produced by the process is minute but rough. Also, glass powder having a diameter of several tens μm to several hundreds of μm is generated from this wall surface. Further, the template also wears out during the polishing operation, and abrasion powder of the template is generated. The wear powder includes not only resin powder but also glass powder because glass cloth is used as a reinforcing base material. These glass powders are made of SiO
Since it is equivalent to _two particles, it damages the workpiece. An object of the present invention is to provide a template material that does not generate wear powder that damages a workpiece.

[0006]

SUMMARY OF THE INVENTION The present invention is a polishing template material comprising a polyarylate fiber as a substrate and a cured product of a thermosetting resin as a matrix.

As the thermosetting resin, any one can be used as long as the cured product gives a cured product having low water absorption and resistance to alkali, but an epoxy resin conventionally used can be used. Among them, a reaction cured product of an epoxy resin and a phenol-added conjugated diene polymer is preferred. This is because the cured product of the reaction between the epoxy resin and the phenol-added conjugated diene-based polymer has particularly low water absorption, and is less susceptible to chemical deterioration and water absorption during polishing, so that the template has a long life.

[0008] It is preferable to use a polyarylate fiber nonwoven fabric as the base material because roughness of the wall surface caused by processing can be minimized. Here, the nonwoven fabric also includes fiber paper manufactured by wet papermaking.

In the step of impregnating and drying a resin varnish in a polyarylate fiber nonwoven fabric, heat shrinkage occurs due to curing of the adhered resin. At this time, if the tensile elongation of the polyarylate fiber non-woven fabric is large, the polyarylate fiber non-woven fabric or fiber paper also shrinks with the curing shrinkage of the resin. This shrinkage is particularly noticeable in the direction perpendicular to the substrate (width direction). Therefore, as the polyarylate fiber nonwoven fabric, the tensile elongation is in the range of 0.5 to 2.0%, and the tensile elongation in the direction of the substrate / the tensile elongation in the direction perpendicular to the substrate = (1-2) / ( It is preferable to use the one in 2-3).
If the tensile elongation is less than 0.5%, the material tends to be hard, and handling in the step of impregnating and drying the resin varnish tends to be difficult, and if it exceeds 2.0%, the shrinkage tends to be large. . In the present invention, the tensile elongation means a test piece cut into a rectangular shape of 15 × 150 mm,
The elongation obtained by measuring the elongation of the test piece at room temperature (25 ° C.) using a tensile tester at room temperature (25 ° C.) with a chuck distance of 180 mm and a pulling speed of 105 mm / min until the test piece breaks is expressed as a percentage (%). It was done.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As the polyarylate fiber, it is preferable to use wholly aromatic polyester obtained by copolymerizing hydroxynaphthoic acid and hydroxybenzoic acid. This polyarylate is a molten liquid crystal polymer and is highly oriented during spinning, so that the spun yarn has ultra-high strength and high heat resistance. In addition, as the polyarylate fiber non-woven fabric, those composed of only polyarylate pulp and short fibers,
Since no other binder or third component is used, the excellent properties of the polymer are reflected as they are, which is preferable. The polyarylate fiber nonwoven fabric can be subjected to a heat calendering treatment to have a predetermined tensile elongation.

When hydroxynaphthoic acid and hydroxybenzoic acid are copolymerized in a molar ratio of hydroxynaphthoic acid of 20 to 50 and hydroxybenzoic acid of 80 to 50, when the liquid crystal polymer is melt-polymerized, It is preferable because the viscosity can be reduced. From such a viewpoint, hydroxynaphthoic acid 40 in a molar ratio,
Particularly preferred is hydroxybenzoic acid 60.

Polyarylate fiber has a very low water absorption compared to aramid fiber of the same type, and has a lower water absorption than a conventional glass cloth base epoxy laminate when combined with a low water absorption resin composition. Can be produced.

The type of the epoxy resin used in the present invention is not particularly limited. For example, bisphenol A epoxy resin, bisphenol S epoxy resin, bisphenol F epoxy resin, biphenol epoxy resin, phenol novolak epoxy resin,
Cresol novolak type epoxy resin, bisphenol A type novolak type epoxy resin, bisphenol F type novolak type epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, hydantoin type epoxy Resins, isocyanurate type epoxy resins, salicylaldehyde novolak type epoxy resins, diglycidyl ether compounds of bifunctional phenols, and diglycidyl ether compounds of bifunctional alcohols. These halides, hydrogenated products and the like can also be used. Some of these may be used in combination.

The phenol-added conjugated diene copolymer is obtained by adding a phenol to a conjugated diene copolymer. As the conjugated diene copolymer, a diene polymer such as polybutadiene is used. Examples of phenols include monofunctional phenols such as phenol, o-cresol, m-cresol, p-cresol, ethylphenol, propylphenol, butylphenol, tert-butylphenol, amylphenol, hexylphenol, hydroquinone, resorcinol, catechol, bisphenol A, bisphenol F, bifunctional phenols such as biphenol, pyrogallol, hydroxyhydroquinone, phloroglysin, phenol novolak, cresol novolac, polyfunctional phenols such as bisphenol A type novolak, isomers thereof, halides and the like, These are used alone or in combination of two or more. The amount of the phenol added is preferably adjusted so that the amount of the phenolic hydroxyl group is 0.1 to 1.0 mol per 100 g of the conjugated diene copolymer. If the added amount of phenols is less than 0.1 mol, the glass transition temperature of the cured product becomes low and the heat resistance becomes poor, and if it exceeds 1.0 mol, the hygroscopicity tends to become large. From such a viewpoint, the addition amount of phenols is determined based on 100 g of the conjugated diene copolymer.
It is particularly preferable to set the phenolic hydroxyl group to 0.2 to 0.5 mol.

The mixing ratio of the epoxy resin and the phenol-added conjugated diene polymer is 80 to 100 parts by weight of the epoxy resin and the phenol-added conjugated diene-based polymer is 80 to 80 parts by weight.
120 parts by weight, preferably 90 to 110 parts by weight, more preferably 95 to 105 parts by weight. If the blending amount of the phenol-added conjugated diene polymer is less than this range, the water absorption will increase, and if it exceeds this range, chemical resistance, especially resistance to alkali chemicals, tends to deteriorate.

In order to accelerate the curing reaction between the epoxy resin and the phenol-added conjugated diene-based polymer, a curing accelerator is added if necessary. As a curing accelerator, an imidazole compound, an organic phosphorus compound, a tertiary amine, a quaternary ammonium salt, or the like is used. When an imidazole compound in which a secondary amino group is masked with acrylonitrile, isocyanate, melamine, acrylate, or the like is used. It has good storage stability when formed into a prepreg, and can secure stable resin flow characteristics in the template material molding process.

The imidazole compound used herein includes imidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 1-benzyl-2-methylimidazole,
-Heptadecyl imidazole, 4,5-diphenylimidazole, 2-methylimidazoline, 2-methyl-4-
Methylimidazoline, 2-phenylimidazoline, 2-
Undecyl imidazoline, 2-heptadecyl imidazoline, 2-isopropylimidazole, 2,4-dimethylimidazole, 2-phenyl-4-methylimidazole, 2-ethylimidazoline, 2-isopropylimidazoline, 2,4-dimethylimidazoline, 2 -Phenyl-4-methylimidazoline and the like, and as a masking agent, there are acronitrile, phenylene diisocyanate, toluene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, methylene bisphenyl isocyanate, melamine acrylate and the like.

Some of these curing accelerators may be used in combination, and the amount of the curing accelerator is preferably 0.01 to 5 parts by weight based on 100 parts by weight of the epoxy resin. 0.01
If the amount is less than 5 parts by weight, the effect is small, and if it exceeds 5 parts by weight, the storage stability of the varnish and the prepreg tends to decrease.

These components to be a matrix of the template material are dissolved in a solvent to form a varnish, impregnated into a substrate, and dried to form a prepreg. As varnish solvents, alcohol-based, ether-based, ketone-based, amide-based,
There are aromatic hydrocarbon type, ester type, nitrile type, etc.
Mixtures can be used if necessary.

In preparing a prepreg, a template material having excellent thickness accuracy can be prepared by strictly controlling the amount of resin adhered to one sheet to a design value. A sheet with a release agent is placed on both sides of the obtained prepreg, and the product temperature is 170 ° C. to 200 ° C., and the product pressure is 0.1 to 3 MPa, preferably 0.5 to 1.5 MPa.
Then, heat and pressure are applied for 30 to 40 minutes to obtain a template material. If the product pressure is lower than 0.1 MPa, the end portion is liable to be worn out, and there is no need to apply pressure exceeding 3 MPa. However, when using a polyarylate fiber nonwoven fabric as the base material,
It is preferable that the pressure does not exceed 1.5 MPa so that the substrate does not tear. For accurate molding, it is preferable to mold the prepreg with as few sheets as possible, preferably with one sheet. Since the accumulated error is reduced, a more accurate template material can be manufactured.

[0021]

【Example】

Example 1 A brominated bisphenol A type epoxy resin having a bromine content of 50% by weight and an epoxy equivalent of 400 (using Epicron 153 (trade name) manufactured by Dainippon Ink and Chemicals, Inc.)
100 parts (parts by weight, hereinafter the same), polybutadiene 100
88 parts of phenol-added polybutadiene (using PP-1000-240 (trade name), manufactured by Nippon Petrochemical Co., Ltd.) having a hydroxyl equivalent of 410 with a phenol addition amount of 0.25 mol per g, and 0.6 parts of isocyanate mask imidazole Was dissolved in 325 parts of methyl ethyl ketone to prepare Varnish A. This varnish A is applied to a thickness of 0.05
mm, weight 54 g / m ² , tensile elongation (substrate direction /
The thickness after drying was 0.12 mm on a polyarylate fiber paper (using a Vulcle HL-50 (trade name) manufactured by Kuraray Co., Ltd.) having a base material perpendicular direction = (0.6 / 1.0). And dried to obtain a prepreg. Five of these prepregs are stacked and heated at a temperature of 175 ° C. and a pressure of 1 MPa.
Heating and pressurization was performed for 0 minute to produce a polishing template material of 500 mm × 500 mm. With respect to the three prepared polishing template materials, the thickness of a total of three points (a total of nine points) at the center and diagonal of one sheet was measured using a micrometer. As a result, the minimum value was 0.579 mm and the maximum value was 0.621 mm. The water absorption was 0.194% (% by weight, the same applies hereinafter) after immersion in water at 23 ° C. for 23 hours, and 0.265% after immersion in 960 hours.
Furthermore, when it was immersed in a 3% aqueous solution of sodium hydroxide at 40 ° C. and examined for alkali resistance, it was immersed in water for 24 hours to obtain a solution of 0.1%.
021% reduction, 0.020% reduction after 480 hours immersion, 960
It was reduced by 0.048% after immersion for hours. The reason that the value of the alkali resistance after immersion for 480 hours is smaller than that after immersion for 24 hours is due to a measurement error.

Example 2 A brominated bisphenol A type epoxy resin was obtained from Sumitomo Chemical Co., Ltd., ESB-400T (trade name, bromine content: 5).
0%, epoxy equivalent 400) and Example 1
A varnish B was prepared in the same manner as described above. The varnish B was applied to the same polyarylate fiber paper as in Example 1 so that the thickness after drying was 0.12 mm, and dried to obtain a prepreg. One prepreg is subjected to a temperature of 175 ° C. and a pressure of 1M.
500mm x 500mm by heating and pressing for 30 minutes at Pa
Was prepared. The thickness of the prepared polishing template material was measured using a micrometer in the same manner as in Example 1. As a result, the minimum value was 0.108 mm and the maximum value was 0.129 mm. The water absorption was 0.194% after immersion in water at 23 ° C. for 23 hours, and 0.283% after immersion in 960 hours. Furthermore, when immersed in a 3% aqueous sodium hydroxide solution at 40 ° C. and examined for alkali resistance, the immersion was reduced by 0.018% after immersion for 24 hours and 0.021% after immersion for 480 hours.
It decreased by 0.035% after immersion for 960 hours.

Example 3 The varnish B was prepared to a thickness of 0.05 mm and a weight of 58 g / m ^2.
Tensile elongation is (substrate direction / substrate perpendicular direction) = (1.3
/1.5) Nonwoven fabric of polyarylate fiber (Kuraray Co., Ltd., using Spunlace N-50 (trade name))
The resulting prepreg was dried and coated so that the thickness after drying was 0.12 mm to obtain a prepreg. One prepreg is heated and pressurized at a temperature of 175 ° C. and a pressure of 1 MPa for 30 minutes to obtain 50 pieces.
A polishing template material of 0 mm × 500 mm was prepared. The thickness of the prepared polishing template material was measured using a micrometer in the same manner as in Example 1. As a result, the minimum value was 0.113 mm and the maximum value was 0.127 mm. The water absorption was 0.190% after immersion in water at 23 ° C. for 23 hours, and 0.298% after immersion in 960 hours. Furthermore, when immersed in a 3% aqueous sodium hydroxide solution at 40 ° C. and examined for alkali resistance, the immersion was reduced by 0.020% after immersion for 24 hours, reduced by 0.022% after immersion for 480 hours, and reduced by 0.038% after immersion for 960 hours. %.

Comparative Example 1 10 parts of a bisphenol A type epoxy resin having an epoxy equivalent of 185 (DER-331L (trade name) manufactured by Dow Chemical Co., Ltd.), 90 parts of the ESB-400T, and a hydroxyl equivalent of 398 were used. PP-1000-240 to 88
Part and 1 part of 1-cyanoethyl-2-ethyl-4-methylimidazole are added to 325 of methyl ethyl ketone.
To prepare a varnish C. Varnish C has a thickness of 0.
A 1 mm, weight 104 g / m ² glass cloth (WEA116E (trade name) manufactured by Nitto Boseki Co., Ltd. was used) was applied so that the thickness after drying was 0.15 mm, and dried to obtain a prepreg. . Five prepregs were piled up and the temperature was 1
Heating and pressurizing at 70 ° C and pressure of 3MPa for 60 minutes, 500
A polishing template material of mm × 500 mm was prepared. The thickness of the prepared polishing template material was measured using a micrometer in the same manner as in Example 1. As a result, the minimum value was 0.581 mm and the maximum value was 0.624 mm. The water absorption was 0.170% after immersion in water at 23 ° C. for 23 hours, and 0.311% after immersion in 960 hours. Further, when immersed in a 3% aqueous sodium hydroxide solution at 40 ° C. and examined for alkali resistance, the immersion was reduced by 0.025% after immersion for 24 hours, reduced by 0.036% after immersion for 480 hours, and reduced by 0.054% after immersion for 960 hours. %.

Comparative Example 2 Varnish D was prepared in the same manner as in Comparative Example 1 except that the brominated bisphenol A type epoxy resin was changed to the above-mentioned Epicron 153.
Was prepared. This varnish D was applied to the same glass cloth as in Comparative Example 1 so that the thickness after drying was 0.15 mm, and dried to obtain a prepreg. One prepreg is heated and pressurized at a temperature of 170 ° C. and a pressure of 3 MPa for 40 minutes to obtain 50
A polishing template material of 0 mm × 500 mm was prepared. The thickness of the prepared polishing template material was measured using a micrometer in the same manner as in Example 1. As a result, the minimum value was 0.148 mm and the maximum value was 0.162 mm. The water absorption was 0.216% after immersion in water at 23 ° C. for 23 hours, and 0.278% after immersion in 960 hours. Further, when immersed in a 3% aqueous sodium hydroxide solution at 40 ° C. and examined for alkali resistance, the immersion for 24 hours was reduced by 0.020%, the immersion for 480 hours was reduced by 0.032%, and the immersion for 960 hours was reduced by 0.048%. %.

Comparative Example 3 A mixed solvent comprising 100 parts of an epoxy resin (Epicoat 1001 (trade name) manufactured by Yuka Shell Epoxy Co., Ltd.), 0.6 part of dicyandiamide, 150 parts of methyl ethyl ketone and 25 parts of dimethylformamide To prepare a varnish E. Using this varnish E, a prepreg was obtained in the same manner as in Comparative Example 2 below. Five prepregs were stacked and heated and pressed at a temperature of 170 ° C. and a pressure of 3 MPa for 90 minutes to produce a polishing template material of 500 mm × 500 mm. The thickness of the prepared polishing template material was measured using a micrometer in the same manner as in Example 1. As a result, the minimum value is 0.56
2 mm, and the maximum value was 0.644 mm. The water absorption was 0.510% after immersion in water at 23 ° C. for 23 hours, and 0.503% after immersion in 960 hours. further,
When immersed in a 3% aqueous sodium hydroxide solution at 40 ° C. and examined for alkali resistance, after immersion for 24 hours, 0.039%
The reduction was 0.045% after 480 hours immersion and 0.057% after 960 hours immersion.

Comparative Example 4 One prepreg prepared in Comparative Example 3 was heated at a temperature of 170 ° C.
Heat and pressurize for 30 minutes at a pressure of 3MPa and 500mm × 5
A 00 mm polishing template material was prepared. The thickness of the prepared polishing template material was measured using a micrometer in the same manner as in Example 1. As a result, the minimum value is 0.133 mm and the maximum value is 0.158.
mm. The water absorption was 0.492% after immersion in water at 23 ° C. for 23 hours, and 0.5% after immersion in 960 hours.
33%. Further, the sample was immersed in a 3% aqueous solution of sodium hydroxide at 40 ° C. to examine the alkali resistance.
0.029% reduction after 4 hours immersion, 0.0 after 480 hours immersion
It decreased by 35% and decreased by 0.055% after immersion for 960 hours.

Next, in order to examine the roughness of the wall surface caused by the processing, three sheets of the polishing template material prepared as described above were stacked and drilled. The drilling conditions are as follows using a drill with a diameter of 0.7 mm.
65,000 revolutions per minute, feed rate 3,500mm
/ Min. Using a new drill, among the three polishing template materials with the number of drilling hits corresponding to 6,000 holes, the bottom one was plated with copper on the inner wall of the hole, and the distance of the plating penetration from the hole wall was measured with a stereoscopic microscope. It measured using. Table 1 shows the results as hole wall roughness.

[0029]

[Table 1]

[0030]

The polishing template material of the present invention is a polishing template material that does not generate hard abrasion powder such as glass powder that damages a workpiece, and is particularly excellent for polishing silicon wafers for semiconductors.

Claims (4)

[Claims] 1. A polishing template material comprising a polyarylate fiber as a base material and a cured product of a thermosetting resin as a matrix. 2. The polishing template material according to claim 1, wherein the cured product of the thermosetting resin is a reaction cured product of an epoxy resin and a phenol-added conjugated diene polymer. 3. The polishing template material according to claim 1, wherein the substrate is a polyarylate fiber nonwoven fabric. 4. The tensile elongation of the polyarylate fiber nonwoven fabric is in the range of 0.5 to 2.0%, and the tensile elongation in the direction of the substrate / the tensile elongation in the direction perpendicular to the substrate = (1-2) /
The polishing template material according to claim 3, which is (2 to 3).