JP6283302B2 - Workpiece holding material - Google Patents

Description

  The present invention relates to an object holding material used in a process of polishing a surface of a silicon wafer, a hard disk or the like.

  In the manufacture of silicon wafers, hard disks and the like, when these surfaces are polished, a hole for holding an object to be polished such as a silicon wafer is formed in a disk having a driving gear meshing with a gear of a surface polishing machine on the outer periphery. Using a workpiece holding material formed from a plurality of pieces, the workpiece is inserted and held in the holding hole of the workpiece holding material, and in this state, the workpiece holding material is mounted on the polishing machine. Then, polishing is performed by driving the object holding material on a flat surface.

Conventionally, such an object holding material is formed by impregnating a glass fiber base material with an epoxy resin and heat-pressing a dried fiber reinforced resin sheet, and processing according to the shape of the polishing machine. It was prepared by.
However, the material to be polished using the glass fiber as described above is excellent in machinability but has a problem that scratches are generated on the surface of the material to be polished by the glass powder.

Accordingly, various materials to be polished using an organic fiber base material such as an aramid fiber have been proposed in order to suppress the generation of scratches (see Patent Document 1, etc.), and in particular, there are many aramid fibers having high strength. It has been adopted.
For example, an object holding material using an aramid fiber, a PBO fiber, an LCP fiber, a fiber substrate made of high-strength PE (nonwoven fabric, woven fabric, UD) as an outer layer and a glass fiber substrate as an intermediate layer has been proposed ( (See Patent Document 2 etc.).
In addition, an object holding material using an aramid fiber base material for the outer layer and a fiber base material made of cellulosic fiber, PVA fiber, acrylic fiber, polyester fiber or the like for the intermediate layer has also been proposed (see Patent Document 3). .
On the other hand, an object holding material made of a thermoplastic resin sheet using polyphenylene sulfide or the like has been proposed (see Patent Document 4).

Japanese Patent Laid-Open No. 11-309667 JP 2009-61531 A JP 2001-105304 A JP 2003-231054 A

However, a material to be polished using aramid fibers is warped due to the hygroscopicity of aramid fibers and is insufficient in terms of thickness accuracy, and in recent years, quality and performance required for polished materials have increased. Further, the production yield is deteriorated by the metal element contained in the aramid fiber, and scratches are generated on the surface of the object to be polished.
Further, in the case where a glass fiber base material is used for the intermediate layer, scratches are generated on the object to be polished by the glass powder.
In addition, since the cellulosic fibers and PVA fibers are hygroscopic, the object-holding material obtained using them is insufficient in terms of warpage and thickness accuracy. Since acrylic fibers also have a high moisture content and have problems with heat resistance, the material to be polished to be polished is insufficient in terms of warpage, thickness accuracy, and durability. Moreover, the to-be-polished material holding | maintenance material using a polyester fiber has a subject in terms of metal element containing.
Furthermore, since the to-be-polished material holding material which consists only of a thermoplastic resin sheet does not use the fiber base material, mechanical strength is inadequate and it is inferior to durability.

An object of the present invention is to provide an object holding material that has good thickness accuracy, does not warp, has a low metal element content, and does not generate scratches on the surface of the object holding material. .
Moreover, the objective of this invention is providing the to-be-polished material holding | maintenance material excellent in durability and workability.

An object of the present invention is an object holding material formed by laminating a plurality of fiber reinforced resin sheets obtained by impregnating a fiber base material with a thermosetting resin, and the outer layer is a fiber using an aramid fiber base material. It reinforced a resin sheet, fiber-reinforced resin sheet of the intermediate layer, polyphenylene Ri sulfide fiber substrate fiber-reinforced resin sheet der using, I from the polyphenylene sulfide fiber substrate, the total fineness 10~600dtex following plain weave It is achieved by a workpiece holding material characterized by the above.

  Further, in the case of the above-described polishing holding material, the fiber base material is 40 to 80% by mass in the workpiece holding material, and the aramid fiber base material in the fiber base material is 10 to 70% by mass. Preferably there is.

  Moreover, it is preferable that content of titanium, magnesium, aluminum, or silicon is 20 ppm or less in the to-be-polished material holding | maintenance material of this invention, respectively.

Moreover, it is preferable that the aramid fiber base material used in the present invention is a woven fabric, a nonwoven fabric, or a long fiber aggregate or short fiber aggregate aligned in one direction.

  The thermosetting resin used in the present invention is selected from the group consisting of epoxy resin, polyimide resin, modified polyimide resin, phenol resin, phenol novolac resin, cresol novolac resin, melamine resin, unsaturated polyester resin, and cyclic olefin polymer resin. Preferably it is selected.

According to the present invention, the thickness accuracy is good, the warp does not occur, the metal element content of titanium, magnesium, aluminum or silicon is small, and the surface of the workpiece holding material is hardly scratched. Material can be provided.
Moreover, the to-be-polished material holding | maintenance material of this invention is excellent in durability and workability, and is low-cost with respect to a 100% aramid fiber use goods.

The material to be polished of the present invention is formed by laminating a plurality of fiber reinforced resin sheets obtained by impregnating a thermosetting resin into a fiber base material, and the outer layer is a fiber using an aramid fiber base material. It consists of a reinforced sheet, The fiber reinforced resin sheet of an intermediate | middle layer consists of a fiber reinforced resin sheet using a polyphenylene sulfide fiber base material, It is characterized by the above-mentioned.
Since the polyphenylene sulfide fiber hardly absorbs moisture, the use of the fiber reinforced resin sheet using the polyphenylene sulfide fiber base material for the intermediate layer does not warp and improves the thickness accuracy. Furthermore, the metal element content can be reduced. Moreover, it can be produced at a low cost and the processability is also good.

Moreover, in this invention, it is preferable that a fiber base material is 40-80 mass% in a to-be-polished material holding material, and it is still more preferable that it is 60-75 mass%.
When the fiber base is less than 40% by mass, the thermosetting resin increases, and the mechanical strength of the object-holding material tends to be insufficient. On the other hand, when the fiber substrate exceeds 80% by mass, the thermosetting resin is decreased, and it tends to be difficult to form the workpiece holding material.

Moreover, it is preferable that it is 10-70 mass% in an aramid fiber base material in a fiber base material, and it is more preferable that it is 15-50 mass%.
If the amount is less than 10% by mass, the aramid fibers are few, and thus the durability of the object-holding material tends to be inferior. On the other hand, when it exceeds 70 mass%, the warp of the workpiece holding material and the thickness accuracy tend to be insufficient.

The aramid fiber used in the present invention includes a para type and a meta type, and an aramid fiber base material containing the para type as a main component is preferable. Here, the reason why the para-aramid fiber is preferable is that the para-aramid fiber has a higher mechanical property value such as tensile strength of the fiber itself than the meta-aramid fiber, and can suppress the wear consumption of the workpiece holding material and extend its life. Because. Moreover, since the para-aramid fiber has a hygroscopic property smaller than that of the meta-aramid fiber, it is suitable for a polishing environment with moisture.
As the para-aramid fiber, poly p-phenylene terephthalamide fiber and poly p-phenylene diphenyl ether terephthalamide fiber are commercially available, and these are common.

The total fineness of the aramid fiber in the present invention is preferably 10 to 1000 dtex, more preferably 50 to 500 dtex.
Further, the single yarn fineness of the aramid fiber in the present invention is preferably 10 dtex or less, and more preferably 5 dtex or less. The range of the number of filaments is preferably 3 to 1000, more preferably 10 to 800.

The strength of the aramid fiber in the present invention is preferably 10.0 cN / dtex or more, more preferably 12.0 cN / dtex or more, and further preferably 20.0 cN / dtex or more.
Further, the elongation is preferably 5.0% or less, and more preferably 3.5% or less.
Furthermore, the elastic modulus is preferably 400 cN / dtex or more, and more preferably 500 cN / dtex or more.

  What is necessary is just to perform manufacture of the aramid fiber used for this invention by a well-known manufacturing method.

  The fiber base material using the aramid fiber can be used in any form of a woven fabric, a nonwoven fabric, or a long fiber aggregate or a short fiber aggregate aligned in one direction, but is a woven fabric from the gist of the present invention. It is preferable.

Although the specification of the fabric is not particularly limited, preferably it has a plain weave having a basis weight 30~300g / ^{m 2,} more preferably more 50 to 200 g / ^{m 2.}

The polyphenylene sulfide fiber used in the present invention is composed of a polymer having a phenylene sulfide unit as a main repeating unit.
Examples of phenylene sulfide units include p-phenylene sulfide units and m-phenylene sulfide units. The polyphenylene sulfide may be a homopolymer composed of p-phenylene sulfide units, m-phenylene sulfide units or the like, or may be a copolymer having these, but from the viewpoint of heat resistance, workability, and economy. Even if it says, the repeating unit of p-phenylene sulfide is the most preferable.

  The polymer type of polyphenylene sulfide includes a crosslinked type, a semi-crosslinked type, and a linear type (linear type). However, since the linear type is most excellent in spinning and stretchability, it is preferable to use the linear type.

  In addition, the polyphenylene sulfide may contain a small amount of various additives such as a colorant as long as the object of the present invention is not impaired.

The polyphenylene sulfide fiber is produced by melt spinning a commercially available pellet-shaped polyphenylene sulfide having a phenylene sulfide unit such as a p-phenylene sulfide unit or an m-phenylene sulfide unit as a repeating unit.
The obtained undrawn yarn is wound once and then subjected to a drawing treatment with a drawing machine. The draw ratio is preferably 2.3 times to 4.0 times.
In the above description, the method of drawing the undrawn yarn once and then drawing it is described. However, a direct spinning drawing method of drawing the undrawn yarn without winding it up may be adopted.

  The strength of the polyphenylene sulfide fiber is preferably 3.0 cN / dtex or more, and the elongation is preferably 30% or more.

  In particular, it is preferable that the fat and oil adhering to the surface of the polyphenylene sulfide fiber is only a polyether component. Oils and fats provided during spinning of ordinary synthetic fibers are generally composed of a plurality of components including an emulsifier, a smoothing agent, an activator, etc. In minutes, the physical properties tend to be unstable.

  The polyether component may be a single component polyether such as polyethylene glycol, polypropylene glycol, or polybutylene glycol, but it is more preferable to use a copolymer polyether in which two or more of these polyethers are copolymerized. Examples of the copolymer polyether include alkyl PO / EO. The polyether-based component, which is a smooth component, forms an oil film on the fiber surface. However, the use of copolymer polyether makes the oil film stronger and damages the fibers in the inner layer of the package due to the tightening that occurs during winding. In addition to suppressing the variation in physical properties by reducing the thickness, it is considered that the oil film is hard to be peeled off by rubbing with various guides due to the strong oil film, the friction coefficient of the fiber is reduced, and the high-order process passing property is improved.

  In general, a polyether-based component may be a polyether ester in which an ester is added to the ether component, but in the present invention, it is an oil and fat composed only of a polyether-based component without adding an ester or the like. It is preferable.

The average molecular weight of the polyether component is preferably 2000 to 13000, more preferably 3000 to 10,000. Can form a strong oil film on the fiber surface with an average molecular weight of 2000 or more, when the average molecular weight is 13000 or less, although the friction coefficient by the viscosity of the oil fat content is increased is higher, a higher processability properties This is because they tend to have no effect.
The average molecular weight referred to in the present invention is a number average molecular weight measured by GPC (gel permeation chromatography).

  In the present invention, as a method for adhering the polyether component to the fiber surface, when adhering, it is used as an aqueous emulsion in which the fat and oil consisting of the polyether component is dispersed in 1 to 10% by mass of water based on the total amount. The water-based emulsion of 1 to 8% by mass is more preferable. When a high-concentration aqueous emulsion having an emulsion concentration exceeding 10% by mass is used, the physical properties may not be stable when a predetermined fat or oil is adhered, and such a low-concentration aqueous emulsion is preferable.

The amount of oil and fat adhering to the surface of the polyphenylene sulfide fiber is preferably 0.4 to 1.5% by mass. That is, 0.4% by mass or more is preferable in order to sufficiently form a strong oil film on the fiber surface due to oil and fat. Also the fat content adhering often, polyphenylene sulfide grease which can not be adhered to the fiber surface and adhere to each roller during spinning, stable production of any point tends to hinder et al, the fat content is 1 0.5 mass% or less is preferable. More preferably, it is 0.6-1.3 mass%.

Moreover, it is preferable that the polyphenylene sulfide fiber base material used in the present invention is a woven fabric, a non-woven fabric, or a long fiber aggregate or short fiber aggregate aligned in one direction.
Moreover, it is preferable that the thickness of a polyphenylene sulfide fiber base material is 30-500 micrometers, and it is preferable that it is 50-200 micrometers.
If the thickness is less than 30 μm, the number of stacked layers increases so that productivity tends to deteriorate. On the other hand, when the thickness exceeds 500 μm, the thickness accuracy tends to deteriorate.

Among them, a plain woven fabric having a total fineness of 10 to 600 dtex is preferable, and when the total fineness exceeds 600 dtex, the woven fabric tends to be thick and lack in thickness accuracy. On the other hand, if it is less than 10 dtex, the number of stacked layers increases, which may cause a problem in terms of productivity and cost. For example, if it is 110 dtex, the weight per unit area is preferably 80 to 100 g / m 2 and the thickness is preferably about 120 to 160 μm. If it is 220 dtex, the unit weight is preferably about 100 to 130 g / m 2 and the thickness is about 160 to 200 μm.

  In the present invention, the thermosetting resin is selected from an epoxy resin, a polyimide resin, a modified polyimide resin, a phenol resin, a phenol novolac resin, a cresol novolac resin, a melamine resin, an unsaturated polyester resin, and a cyclic olefin polymer resin. It is preferable. An epoxy resin is particularly preferable.

  Further, a thermosetting resin and a thermoplastic resin may be combined. Alternatively, various additives such as a colorant may be contained in the resin as long as the object of the present invention is not impaired.

In the present invention, the metal element content of titanium, magnesium, aluminum or silicon in the workpiece holding material is preferably 20 ppm or less and more preferably 10 ppm or less.
When each of the above metal elements exceeds 20 ppm, the object to be polished is contaminated and the product yield tends to be lowered.
By combining a polyamidosulfide fiber base material with an aramid fiber base material as the fiber base material, the metal element content can be reduced.

What is necessary is just to manufacture the fiber reinforced resin sheet which concerns on this invention with the following method, for example. That is, each fiber base material is impregnated with a resin and dried to prepare a fiber reinforced sheet.
Specifically, when a thermosetting resin is used, a resin composition in which a thermosetting resin is dissolved in a solvent is prepared, and after applying the resin composition to the fiber substrate , an extra portion is used using a bar coater or a clearance roll. A fiber reinforced sheet can be prepared by scraping off the resin composition.

  Next, the workpiece holding material is formed as follows, for example. That is, a plurality of fiber reinforced sheets are laminated so that the outer layer is a fiber reinforced sheet using a polyphenylene sulfide fiber base material, and these are joined to form a laminate.

  After laminating a plurality of fiber reinforced sheets, a known molding method such as an autoclave molding method or a compression molding method can be employed as a method for joining them, and the desired shape, thermosetting resin or heat What is necessary is just to apply the optimal shaping | molding method according to the kind of resin to use, such as a plastic resin. In particular, an autoclave molding method and a compression molding method are preferable, and the chemical bond between the adhesive component attached to the fiber surface can be promoted, and the improvement in the adhesion between the fiber base material and the resin can be expressed more effectively.

  The obtained laminated plate is cut into a desired shape such as a disk shape having a driving gear meshing with a gear of a surface polishing machine on the outer periphery, and one hole for holding an object to be polished such as a silicon wafer The material to be polished of the present invention is obtained by forming a plurality of materials.

The present invention will be specifically described below with reference to examples.
The properties of the laminates produced in the examples and comparative examples were evaluated by the following methods.

1) Thickness accuracy The laminate was molded into 1000 mm × 1000 mm, and a total of 9 points at 8 peripheral edges and 1 central part were measured with a micrometer and evaluated by the difference between the maximum value and the minimum value.

2) Warpage amount The laminate was molded into a size of 1000 mm x 1000 mm and evaluated by the maximum value of the amount of lift at the end when it was placed flat on a horizontal plate.

3) Metal content After carbonizing the fiber base material in a platinum crucible, it was incinerated in an electric furnace and alkali-melted with sodium carbonate (Na ₂ CO ₃ ), and the volume was adjusted with ultrapure water to obtain a measurement sample. The content of each metal element was measured using an ICP emission spectroscopic analyzer (CIROS CCD manufactured by AMETEK).

4) Polishing test A laminated plate molded to 1000 mm x 1000 mm was processed into a disk shape with an 11 inch diameter, a plurality of teeth were formed on the outer periphery, and four holding holes with a 3.5 inch diameter were further passed through. Thus, an object holding material was prepared. Next, an abrasive hard disk was fitted with a 3.5-inch diameter aluminum hard disk in the holding hole of the polished object holding material, and the polishing apparatus was operated to perform polishing. Polishing was repeated 100 times, and a total of 2000 workpieces were polished.

5) Scratch failure The surface state of the object to be polished after the polishing test was observed, the presence or absence of scratches was examined, and the failure rate was determined.

6) Service life Evaluation was made based on the degree of wear of the workpiece holding material during the polishing test. That is, the number of usable batches at the usable wear level was examined, and expressed as an index when the number of usable batches in Comparative Example 3 below was defined as 100.

7) Machinability When creating the workpiece holding material, the productivity of the outer teeth and holding holes was relatively determined. From the ones with good workability, ◎, ○, △, × It was evaluated.

Moreover, the following were used as each fiber base material and resin varnish.
1) Substrate 1: Aramid fiber woven fabric (Aramid fiber (trade name: Kevler 29, 220 dtex / 133f manufactured by Toray DuPont Co., Ltd.), basis weight 60 g / m ² , plain woven fabric with a thickness of 150 μm)
2) Base material 2: Aramid fiber nonwoven fabric (Aramid fiber (manufactured by Toray DuPont, trade name: Kevler 29, 1.7 dtex × 3 mm), basis weight 72 g / m ² , wet nonwoven fabric with a thickness of 100 μm)
3) Substrate 3: Polyphenylene sulfide (PPS) fiber woven fabric (manufactured by KB Seiren, trade name: Gradio, fineness 110 dtex / 24f, basis weight 95 g / m ² , plain woven fabric with a thickness of 150 μm)
4) Substrate 4: Glass fiber woven fabric (Glass fiber (manufactured by Asahi Shebel Co., Ltd., trade name: A2116 / AS450), basis weight 209 g / m ² , plain woven fabric with a thickness of 180 μm)
5) Resin varnish: bisphenol A type epoxy resin varnish containing dicyandiamide as a curing agent and 2-ethyl-4-methylimidazole as a curing accelerator

Example 1
A resin varnish was applied to the substrate 1, impregnated, and then semi-cured by drying to obtain prepreg A.
A resin varnish was applied to the substrate 3, and after impregnation, semi-curing was performed by drying to obtain a prepreg B.
1 sheet of prepreg A for each outer layer, 6 sheets of prepreg B for the intermediate layer, a total of 8 sheets of prepregs are sandwiched between 2 mirror plates, heating rate 2.0 ° C / min, curing temperature 175 ° C x 60 minutes The laminate 1 was obtained by heating and pressing under a pressure of 3.0 MPa.

(Example 2)
A resin varnish was applied to the substrate 2, and after impregnation, semi-curing was performed by drying to obtain a prepreg C.
Two prepregs C on both outer layers, 6 prepregs B on the intermediate layer, a total of 10 prepregs sandwiched between two mirror plates, heating rate 2.0 ° C / min, curing temperature 175 ° C x 60 minutes The laminate 2 was obtained by heating and pressing under a pressure of 3.0 MPa.

(Comparative Example 1)
Eight prepregs A are laminated, sandwiched between two mirror plates, and heated and pressure-molded at a heating rate of 2.0 ° C./min, a curing temperature of 175 ° C. × 60 minutes, and a pressure of 3.0 MPa. Obtained.

(Comparative Example 2)
The resin varnish was applied to the substrate 4, and after impregnation, semi-curing was performed by drying to obtain a prepreg D having a resin content of 35% by weight.
Two prepregs A on both outer layers, three prepregs D on the intermediate layer, a total of seven prepregs sandwiched between two mirror plates, heating rate 2.0 ° C / min, curing temperature 175 ° C x 60 minutes Then, heat-press molding was performed at a pressure of 3.0 MPa to obtain a laminate 4.

(Comparative Example 3)
Six prepregs D are laminated, sandwiched between two mirror plates, and heated and pressure-molded at a heating rate of 2.0 ° C./min, a curing temperature of 175 ° C. × 60 minutes, and a pressure of 3.0 MPa. Obtained.

  Table 1 shows the physical properties and evaluation results of these laminates.

Claims (5)

A material to be polished that is formed by laminating a plurality of fiber reinforced resin sheets impregnated with a thermosetting resin into a fiber base material, and the outer layer is a fiber reinforced resin sheet using an aramid fiber base material, fiber-reinforced resin sheet of the intermediate layer, a polyphenylene sulfide fiber-reinforced resin sheet der using fiber substrate is, the polyphenylene sulfide fiber substrate, wherein the Rukoto such a total fineness 10~600dtex following plain weave Workpiece holding material.   2. The object to be polished according to claim 1, wherein in the material to be polished, the fiber base is 40 to 80% by mass, and the aramid fiber base in the fiber base is 10 to 70% by mass. Material holding material.   The material to be polished according to claim 1 or 2, wherein the content of titanium, magnesium, aluminum or silicon is 20 ppm or less. The aramid fiber base material is a woven fabric, a non-woven fabric, or a long fiber aggregate or a short fiber aggregate aligned in one direction, and holds an object to be polished according to any one of claims 1 to 3. Wood.   The thermosetting resin is selected from epoxy resin, polyimide resin, modified polyimide resin, phenol resin, phenol novolac resin, cresol novolac resin, melamine resin, unsaturated polyester resin, and cyclic olefin polymer resin. The to-be-polished object holding material according to any one of claims 1 to 4.