JP2002103210A - Material to be polished - Google Patents

Abstract

[PROBLEMS] To provide an object-to-be-polished holding material that is not easily adhered to an upper plate of a polishing apparatus, and to reduce defects of the object due to line trouble. A holding member for an object to be polished is constituted by a plate-like body formed by heating and pressing one sheet-like fiber base material impregnated with a thermosetting resin or a plurality of superposed sheets. At least the surface layer is formed of a sheet-like fiber base material impregnated with a thermosetting resin containing fluororesin particles.

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, such an object-to-be-polished holding material is formed of a plate-like body obtained by processing a thermosetting resin laminate. The thermosetting resin laminate is a glass fiber woven fabric base epoxy resin laminate, an aramid fiber nonwoven fabric base epoxy resin laminate, a cotton fabric base phenol resin laminate, or the like. Laminates for forming the polished material holding material are generally prepregs obtained by impregnating and drying a thermosetting resin containing no inorganic or organic particles into a base material such as a glass fiber woven fabric, an aramid fiber nonwoven fabric, or a cotton cloth. One prepreg or a plurality of prepregs are formed by heating and pressing. These laminates are processed into an object-to-be-polished holding material as described above, and are used for polishing silicon wafers, hard disks and the like.

[0004]

In the polishing operation, the above-mentioned polished work holding material is mounted on a polishing apparatus, the polished work is held in a through hole of the polished work holding material, and silica (SiO ₂ ), alumina (Alumina) is used. The polishing is performed by supplying an aqueous polishing liquid in which fine particles such as Al ₂ O ₃ ) and ceria (CeO ₂ ) are dispersed. The operation of attaching and detaching the workpiece holding material to and from the polishing apparatus, such as when replacing the workpiece holding material with a new one, is performed manually or by an automatic machine, but recently, the automatic machine is often used. It has become. In addition, the removal of the object to be polished and the supply of the object to be newly polished are often performed by an automatic machine.

As described above, since a water-based polishing liquid is used for the polishing operation, the object-to-be-polished is likely to adhere to the upper plate of the polishing apparatus. When attaching or detaching the object-to-be-polished holding material, or taking out the object-to-be-polished, the object-to-be-polished holding material comes into close contact with the upper plate and is lifted together with the upper plate. Such a situation is not a serious problem when manually attaching / detaching the workpiece holding material or taking out / supplying the workpiece, but it is a cause of line trouble when performing the operation by an automatic machine. Become.

An object of the present invention is to provide an object-to-be-polished holding material that does not easily adhere to the upper plate of the polishing apparatus, and to reduce defects of the object due to line trouble. Also, the polishing operation efficiency is increased.

[0007]

In order to solve the above-mentioned problems, the object-to-be-polished holding material according to the present invention comprises heating a sheet-like fiber base material impregnated with a thermosetting resin or a plurality of superposed sheets. It is constituted by a pressure-formed plate-like body, and at least the surface layer is constituted by a sheet-like fiber base material impregnated with a thermosetting resin containing fluororesin particles.

The reason why the object-to-be-polished holding material containing the fluororesin particles in the surface layer is difficult to adhere to the upper plate of the polishing apparatus is considered as follows. Fluororesin is one of the solid materials having the lowest surface energy, and has excellent non-adhesive and non-adhesive properties. Therefore, the holder for the object to be polished containing the particles in the surface layer has low wettability to water. Since the polishing is performed by supplying the water-based polishing liquid as described above, moisture is interposed between the upper plate of the polishing apparatus and the holding material for the object to be polished, and the two are in a state where they are easily adhered to each other. The material to be polished has a low wettability to water, and thus it is difficult to adhere to the upper plate of the polishing apparatus.

It is necessary that the fluororesin to be present on the surface of the holder for the object to be polished is in the form of particles so as not to degrade the mechanical properties such as the bending strength of the holder for the object to be polished. It is easy to manufacture and excellent in cost. The holder for the object to be polished can be made of a thermosetting resin modified with a fluororesin, and the fluorine resin can be present on the surface. However, the same effect as the holder for the object to be polished according to the present invention cannot be expected.

[0010] The holding material for the object to be polished according to the present invention contains fluorine resin particles, so that the coefficient of friction on the surface is reduced and the abrasion resistance is improved. Also has the side effect of being longer.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, the object-to-be-polished holding material according to the present invention is obtained by heating a sheet-like fiber base material impregnated with a thermosetting resin containing fluororesin particles or a plurality of superposed sheets. It is formed by pressure molding. In order to avoid adhesion to the upper plate of the polishing apparatus, at least the surface layer of the holding material for the object to be polished is formed of a sheet-like fiber base material impregnated with the thermosetting resin containing fluororesin particles and dried. The sheet-like fiber base material is not particularly limited as long as it is a sheet-like fiber base material such as a woven or nonwoven fabric of glass fiber or aramid fiber, or a cotton cloth, which can constitute the holding member for the object to be polished. However, the effect of preventing adhesion to the upper plate of the polishing apparatus is particularly remarkable for the holder for the object to be polished in which the organic fiber sheet-like fiber base material is selected. This is because if the resin constituting the workpiece holding material is the same, the adhesive force between the upper plate of the polishing apparatus and the workpiece holding material is substantially the same regardless of the type of the sheet-like fiber base material, but the organic fiber sheet Since the object-to-be-polished holding material using the base material is relatively lightweight, it is easily lifted together with the polishing machine upper plate when it comes into close contact with the upper plate. Therefore, reducing the wettability of water with respect to the light material to be polished keeps the effect of preventing adhesion to the upper plate of the polishing apparatus more remarkably.

The thermosetting resin impregnated in the sheet fiber substrate is not particularly limited, such as phenol resin, epoxy resin, polyester, and polyimide. However, thermosetting resins having relatively high heat resistance, such as phenolic resins and polyimides (for example, resins having a portion that is not directly involved in adhesion, such as a benzene nucleus, having a high density in the molecular skeleton) are hard, although the resin itself is hard. Since the adhesiveness is relatively low, the interface between the base material and the resin is easily peeled during polishing, and the resin itself is liable to be broken or worn. For this reason, it is preferable to use an epoxy resin as the thermosetting resin. Further, in order to reduce the brittleness of the epoxy resin, an epoxy resin modified by adding a flexible component such as a rubber component is also preferable.

[0013] The forming of the plate-like body for the holder for the object to be polished is
Sheet-like fiber substrate 1 impregnated with a thermosetting resin and dried by heating
One or a plurality of superposed sheets are covered with a release film, sandwiched between mirror plates, and heated and pressed between hot press plates.
The number of superimposed sheet-like fiber substrates is changed according to the polishing conditions such as the type and thickness of the object to be polished such as a silicon wafer and a hard disk.

[0014]

EXAMPLES The following were prepared as sheet-like fiber substrates. (Aramid fiber non-woven fabric base material) Para-aramid fiber chop (fiber diameter: 1.5 denier, fiber length: 3 mm, Teijin's "Technola") and meta-aramid fiber chop (fiber diameter: 3 denier, fiber length: 6 mm, A softening temperature of 280 ° C., Teijin's “Cornex”, unstretched) was mixed, sprayed with a water-soluble epoxy resin binder (glass transition temperature of 110 ° C.), and dried by heating to obtain a nonwoven fabric having a unit weight of 60 g / m ² . The blending weight ratio of para-aramid fiber / meta-aramid fiber / resin binder is 85/5/10.

Further, the non-woven fabric is heated and compressed by passing the non-woven fabric between a pair of heat rolls, and heat-fused meta-aramid fibers to para-aramid fibers. The para-aramid fiber is, specifically, poly p-phenylene 3,
4-diphenyl ether terephthalamide fiber. (Polyester fiber woven fabric base material) It is a woven fabric having a woven density of 48 lines / 48 lines and a unit weight of 130 g / m ² (“BKE Poplin” manufactured by Asahi Kasei). (Glass Fiber Woven Substrate) A glass fiber woven fabric having a unit weight of 107 g / m ² (“GC-21” manufactured by Asahi Schwebel)
6 ").

The following were prepared as prepregs. First, a bisphenol A epoxy resin varnish (A) containing dicyandiamide as a curing agent and 2-ethyl-4-methylimidazole as a curing accelerator was prepared. The varnish (A) was coated with fluororesin particles (average particle size 9 μm, surface area 3 m ² / g, “Teflon (registered trademark) MP1300” manufactured by DuPont-Mitsui Fluorochemicals) in a resin solid mass ratio of bisphenol A epoxy resin A varnish (B) was prepared so that the fluororesin particles were 80/20. This is an epoxy resin containing fluororesin particles. The varnishes (A) and (B) were impregnated into the respective sheet-like fiber base materials in the combinations shown in Table 1 and dried by heating to obtain prepregs. For each prepreg, the amount of resin adhered was adjusted so that the thickness of one of the prepregs when heated and pressed was 0.1 mm.

[0017]

[Table 1]

Example 1 A release film (a polypropylene film having a thickness of 50 μm) was placed on both sides of a stack of five prepreg ARBs, sandwiched between mirror plates, and formed into a kraft paper layer having a thickness of 10 mm.
Was heated and pressed between press hot plates through the cushion material of Example 1 to obtain a laminate having a thickness of 0.5 mm. This laminated plate was processed into an 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.

Example 2 A prepreg ERB was used in place of the prepreg ARB, and the other conditions were the same as those in Example 1 except that a polished-piece holder having a thickness of 0.5 mm was used.

Example 3 A prepreg GRB was used in place of the prepreg ARB, and the other conditions were the same as in Example 1, except that a polished-substance holding material having a thickness of 0.5 mm was used.

Example 4 Three prepreg ARAs were superimposed, and one prepreg ARB was superimposed on both surfaces thereof, and each was heated and pressed.
Hereinafter, in the same manner as in Example 1, a workpiece to be polished having a thickness of 0.5 mm was obtained.

Conventional Example 1 A prepreg ARA was used in place of the prepreg ARB, and other than that, a polished work holding material having a thickness of 0.5 mm was used similarly to the first embodiment.

Conventional Example 2 A prepreg ERA was used in place of the prepreg ARB, and other than that, a workpiece to be polished having a thickness of 0.5 mm was used similarly to the first embodiment.

Conventional Example 3 A prepreg GRA was used in place of the prepreg ARB, and other than that, a workpiece to be polished having a thickness of 0.5 mm was used similarly to the first embodiment.

A polishing operation was performed using the above-mentioned respective examples and the conventional example. The object to be polished is a 3.5-inch aluminum hard disk. As an evaluation of the frequency of adhesion of the workpiece holding material to the upper plate of the polishing apparatus, the wettability of the workpiece holding material to water and the number of times that the workpiece holding material is brought into close contact with the upper board of the polishing apparatus (the number of troubles) Table 2 shows the evaluation results of the service life of the holding material for the object to be polished.
Shown in The wettability of the holder for the object to be polished with water is measured by dropping distilled water on the surface of the holder for the object to be polished and measuring the contact angle.
The number of troubles is determined by examining the number of times the workpiece holding material is lifted in the polishing operation of 1,000 batches (one batch mounts five workpiece holding materials in a polishing apparatus and grinds 20 hard disks). . The service life of the holder for the object to be polished is determined based on the wear level of the gear portion, the number of batches that can be used repeatedly is investigated, and the service life of Conventional Example 3 is set to 100 (the larger the index, the longer the service life). ).

[0026]

[Table 2]

[0027]

As is clear from Table 2, the number of times that the object-to-be-polished holding material according to the present invention is brought into close contact with the upper plate of the polishing apparatus is extremely reduced, and the occurrence of line troubles is reduced. In addition, the holder for an object to be polished according to the present invention has less wear and the service life is extended. With these, the production yield of the object to be polished can be improved and the cost can be significantly reduced.

Claims (2)

[Claims] 1. A thermosetting resin comprising a sheet-like fiber base material impregnated with a thermosetting resin or a plate-like body formed by heating and pressing a plurality of superposed sheets. An object-to-be-polished holding material, comprising a sheet-like fiber base material impregnated with a. 2. The holder for an object to be polished according to claim 1, wherein the sheet-like fiber base is made of organic fibers.