JP2002052461A - Polished object holding member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polished object holding member for suppressing the scratching of a polished object. SOLUTION: The polished object holding member is formed by heating pressure molding of the layer of a para-aramide fiber substrate impregnated with a thermosetting resin. As the para-aramide fiber substrate, the member adopts a nonwoven cloth with para-aramide fiber chops and para-aramide fiber pulps mixedly made. A nonwoven cloth of the para-aramide fiber pulps also can be adopted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION In the manufacturing process of silicon wafers, hard disks and the like, there is a process of polishing the surfaces of these. According to the present invention, in the polishing step, a silicon wafer,
The present invention relates to a holding material for holding an object to be polished such as a hard disk.

[0002]

2. Description of the Related Art The above-mentioned object-to-be-polished holding material has a structure in which one or a plurality of through-holes for holding a material to be polished are formed in a disk around which a driving gear is formed. The work is polished by fitting the work into the through hole, mounting the work in a polishing apparatus, and driving the holding member in a plane.

Conventionally, a processed material of a laminated board for electrical insulation has been used as an object-to-be-polished holding material. The laminate is formed by heating and pressing a layer of a sheet-like substrate (prepreg) impregnated with a thermosetting resin and dried. For example, glass fiber woven base epoxy resin laminate, glass fiber nonwoven base epoxy resin laminate, aramid fiber base epoxy resin laminate, and the like. Among them, an aramid fiber-based epoxy resin laminate has been found to be effective in suppressing the occurrence of scratches (polishing scratches), and has become widely used as a holder for a polished object.

[0004]

The characteristics required of the holder for the object to be polished include abrasion resistance, plate thickness accuracy, warpage characteristics, and high strength. As the quality and performance required for the object to be polished have increased, there has been a demand for a holding material that does not generate scratches (polishing scratches) on the object to be polished, has higher strength, and has a long service life. Conventionally, the aramid fiber-based epoxy resin laminate used for the object-to-be-polished retainer has a better abrasion resistance than the glass fiber-based epoxy resin laminate, and has the effect of suppressing the occurrence of scratches. Further improvements are desired.

[0005] The problem to be solved by the present invention is to further suppress the occurrence of scratches, and to provide such an object-to-be-polished holding material using an aramid fiber nonwoven fabric base material.

[0006]

In order to solve the above-mentioned problems, the object-to-be-polished holding material according to the present invention comprises forming a layer of a para-type aramid fiber nonwoven fabric (prepreg) impregnated with a thermosetting resin by heating and pressing. The para-type aramid fiber chop and the para-type aramid fiber pulp are included as the para-type aramid fiber, and the total mass of the para-type aramid fiber chop and the para-type aramid fiber pulp is 100, and the para-type aramid fiber pulp The mass is 5 or more. Another invention is characterized in that the para-aramid fiber is a para-aramid fiber pulp.

As described above, a nonwoven fabric obtained by mixing para-type aramid fiber chops and para-type aramid fiber pulp or a non-woven fabric consisting of para-type aramid fiber pulp is impregnated with a thermosetting resin and heated and pressed to form a support for a polished work. The presence of para-type aramid fiber pulp contributes to suppressing the occurrence of scratches. The reason is considered as follows. The chop is obtained by cutting a spun straight fiber into a predetermined size that can be formed into a paper. The pulp is obtained by beating the fiber. Therefore, pulp has an ability to be entangled by itself, and it is possible to strongly bind fibers together by making a paper together with a chop. This strong binding contributes to the improvement of the abrasion resistance of the holding material of the object to be polished, and suppresses the fluffing and falling off of the fiber which causes the scratch, so that the object to be polished is hardly scratched. In addition, when using the nonwoven fabric which mixed the para-type aramid fiber chop and the para-type aramid fiber pulp, if the compounding mass of the para-type aramid fiber pulp is less than 5, the fiber fuzzing during use of the holding material for the polished material is high. As a result, scratches are likely to occur.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, the object-to-be-polished holding material according to the present invention is formed by heating and pressing a layer of an aramid fiber base material impregnated with a thermosetting resin. The aramid fiber base material is a para-type aramid fiber non-woven fabric.If the non-woven fabric is a mixture of para-type aramid fiber chops and para-type aramid fiber pulp, the compounding mass of the para-type aramid fiber pulp is the para-type aramid fiber chop and the para-type aramid fiber chop. Assuming that the total mass of the type aramid fiber pulp is 100, preferably,
10 or more. Para-type aramid fibers are poly-P-phenylene terephthalamide represented by DuPont "Kevlar" and poly-P represented by Teijin "Technola"
-Phenylene 3,4'-diphenyl ether terephthalamide.

The thermosetting resin impregnated in the aramid fiber non-woven fabric is not particularly limited, and may be phenol resin, epoxy resin, polyester, polyimide, or the like. However, thermosetting resins with relatively high heat resistance, such as phenolic resins and polyimides (for example, resins that have a portion that is not directly involved in adhesion, such as benzene nuclei, in the molecular skeleton at high density)
It was found that, although the resin itself was hard, the adhesiveness was relatively low, so that the interface separation between the aramid fiber and the resin was likely to occur during polishing, and the resin itself was liable to breakage and wear. For this reason, it is preferable to use an epoxy resin as the thermosetting resin.

The holding material for the object to be polished is formed by covering a layer of aramid fiber non-woven fabric (prepreg) impregnated and dried with a thermosetting resin with a release film, sandwiching the layer between mirror plates, and heating and pressing between press hot plates. Molding. The prepreg layer may be a single prepreg or a plurality of prepregs. The number of prepregs to be used is changed depending on the type of the object to be polished such as a silicon wafer or a hard disk or the polishing conditions, or another base material is appropriately selected and combined. When three or more prepregs are laminated to secure the thickness to form the holder for the object to be polished, a layer of a polyester fiber base material impregnated with a thermosetting resin is used for the core layer to reduce the cost. be able to.

[0011]

EXAMPLES Example 1 (Production of nonwoven fabric of aramid fiber) Para-type aramid fiber chop (fiber diameter: 1.5 denier, fiber length: 3 mm, "Kevlar" made by DuPont) and para-type aramid fiber pulp (fiber diameter: 1) 0.5 denier, fiber length: 3 mm), sprayed with a water-soluble epoxy resin binder (glass transition temperature: 110 ° C.), and dried by heating to form a nonwoven fabric. Further, the nonwoven fabric was heated and compressed by being passed between a pair of heat rolls. The manufactured nonwoven fabric has a unit mass of 72 g / m ² , and the blending mass ratio of para-type aramid fiber chop / para-type aramid fiber pulp is 80/20. (Preparation of prepreg) The above-mentioned aramid fiber nonwoven fabric is impregnated with a brominated bisphenol A epoxy resin varnish and dried.
A prepreg having a resin content of 52% by mass was obtained. (Manufacture of laminated board) Six prepregs are stacked and
The laminate was obtained by heating and pressing at a heating temperature of 170 ° C. and a lamination pressure of 3.9 MPa.

Example 2 In Example 1, the mixing mass ratio of para-type aramid fiber chop / para-type aramid fiber pulp was 50/50,
The other conditions were the same as in Example 1.

Example 3 In Example 1, the mixing mass ratio of para-type aramid fiber chop / para-type aramid fiber pulp was 90/10,
The other conditions were the same as in Example 1.

Example 4 In Example 1, the blending mass ratio of para-type aramid fiber chop / para-type aramid fiber pulp was 95/5, and the other conditions were the same as in Example 1.

Example 5 In Example 1, the mixing mass ratio of para-type aramid fiber chop / para-type aramid fiber pulp was set to 0/100.
The other conditions were the same as in Example 1.

Example 6 (Preparation of polyester fiber base material) Woven density: 48 vertical / 48 horizontal, unit weight 130 g / m ² woven cloth (“B” manufactured by Asahi Kasei Corporation)
KE poplin ") was prepared. (Production of prepreg) The woven polyester fiber was impregnated with a brominated bisphenol A epoxy resin varnish and dried to obtain a prepreg. The amount of the impregnated resin was adjusted so that the thickness of one prepreg after heat-pressing was 0.1 mm. (Manufacture of Laminated Board) Four polyester fiber woven prepregs were stacked, and one aramid fiber nonwoven prepreg prepared in Example 1 was arranged on both sides thereof. Thus, a laminate having a thickness of 0.6 mm was obtained.

Conventional Example 1 The procedure of Example 1 was repeated, except that only para-type aramid fiber chops (fiber diameter: 1.5 denier, fiber length: 3 mm, made by DuPont "Kevlar") were used as para-type aramid fibers. An aramid fiber non-woven fabric was prepared, and was heated and pressed using the same as in Example 1 to obtain a laminate having a thickness of 0.6 mm.

Conventional Example 2 The procedure of Example 1 was repeated except that only para-type aramid fiber chops (fiber diameter: 1.5 denier, fiber length: 3 mm, Teijin Technora) were used as para-type aramid fibers. An aramid fiber non-woven fabric was prepared, and was heated and pressed using the same as in Example 1 to obtain a laminate having a thickness of 0.6 mm.

Comparative Example 1 In Example 1, the blending mass ratio of para-type aramid fiber chop / para-type aramid fiber pulp was 97/3, and the other conditions were the same as in Example 1.

The laminates in each of the above embodiments, the conventional example, and the comparative example were machined to obtain a holder for the object to be polished. This polished work holding material is a disk having a diameter of 10 inches with a gear formed around the polished work and provided with four 3.5-inch diameter through holes for fitting the polished work. 3.5 to be polished
Using an inch aluminum hard disk, the scratch generation rate, the number of times of crash occurrence, and the life index of the material to be polished in the polishing work of 200 batches were examined. Table 1 shows the results. Here, the polishing operation of one batch is
This is an operation in which four polished objects are held by one polished object holding material, and the five polished object holding materials are simultaneously planetary-moved to polish each polished object. Scratch occurrence rate is 400
This is the ratio of scratches generated when 0 (4 × 5 × 200) pieces are polished. The number of crash occurrences is the number of batches in which a crash has occurred in a 200-batch polishing operation. The crash is a destructive phenomenon in which the gear portion of the workpiece holding material is torn. The most remarkable part of the polished work holding material is the gear portion formed around the polished work holding material (disc). This is because a tear load is applied in the vertical direction. Normally, when polishing a hard disk or the like, several pieces of a workpiece to be polished having a gear formed therearound are mounted on a polishing apparatus having an internal gear and a sun gear, and further, the workpiece is polished into a through hole of the workpiece to be polished. An object is fitted and the planetary movement is performed to rotate and polish. Since the thickness of the workpiece holding material is thinner than the thickness of the workpiece, almost no vertical pressure is applied to the workpiece holding material during polishing. For this reason, the rotational force applied to the gear portion of the object-to-be-polished holding works so as to escape in the vertical direction of the object-to-be-polished holding material, and the adjacent teeth of the gear are easily torn and broken. The life index is determined based on the degree of wear of the gear portion. Specifically, assuming that the number of polished objects that can be polished until the wear of the gear portion of the polished material holding material of Conventional Example 2 becomes unusable is 100, the wear of the gear portion of each polished material holding material is used. The number of objects to be polished that can be polished until an impossible state was obtained was determined as an index. Table 1 also shows the mixing mass ratio of the para-aramid fiber chop and the para-aramid fiber pulp.

[0021]

[Table 1]

[0022]

According to the present invention, there is provided an object-to-be-polished holding material formed by heating and pressing a layer of a para-type aramid fiber substrate impregnated with a thermosetting resin, wherein the para-type aramid fiber is a para-type aramid fiber. By using a nonwoven fabric made of a mixture of fiber chops and para-type aramid fiber pulp as a base material, and using a nonwoven fabric made of para-type aramid fiber pulp as a base material, wear of the gear portion is suppressed. As a result, the occurrence of scratches and crashes can be suppressed. When the non-woven fabric is obtained by mixing para-aramid fiber chops and para-aramid fiber pulp as the para-aramid fiber, and the total mass of para-aramid fiber chops and para-aramid fiber pulp is 100, para-aramid fiber By setting the mass of the pulp to 10 or more, the service life of the holding material for the object to be polished is prolonged. As a result, the production yield of the object to be polished can be improved and the cost can be significantly reduced.

Claims (4)

[Claims] 1. A holder for an object to be polished, wherein a layer of a non-woven fabric of a para-type aramid fiber impregnated with a thermosetting resin is heat-pressed, wherein the para-type aramid fiber is a chopped para-aramid fiber and a para-type aramid fiber. A material to be polished, comprising fibrous pulp, wherein the total mass of the para-type aramid fiber chop and the para-type aramid fiber pulp is 100, and the mass of the para-type aramid fiber pulp is 5 or more. 2. The holding material for an object to be polished according to claim 1, wherein the mass of the para-type aramid fiber pulp is 10 or more, where the total mass of the para-type aramid fiber chop and the para-type aramid fiber pulp is 100. 3. A holding material for an object to be polished, obtained by heating and pressing a layer of a para-type aramid fiber nonwoven fabric impregnated with a thermosetting resin, wherein the para-type aramid fiber is a para-type aramid fiber pulp. A material to be polished holding. 4. The holder for an object to be polished according to claim 1, wherein the core layer is a layer of a polyester fiber base material impregnated with a thermosetting resin.