JP2007069295A - Holder for polishing object - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve peeling strength between a template and a thermosensitive material under dry and wet conditions respectively, and also to reduce a difference in the peeling strength under both conditions. <P>SOLUTION: The holder for a polishing object is formed by stacking the template 1 made of a fiber-reinforced resin and a backing material 3 for holding the object using a thermoplastic adhesive material 2, while a primer layer 5 is interposed between the template 1 and the material 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a workpiece holder that serves to hold a workpiece in a polishing process of a silicon wafer used for a semiconductor substrate or a glass substrate used for a display.

  The polishing machine includes an upper surface plate and a lower surface plate, and each has a mechanism for rotating, rotating and revolving. A polishing pad is adhered to the lower surface plate, and an object to be polished is held on the upper surface plate by an object holding tool. Then, the object to be polished is pressed against the polishing pad, and processing is performed by sliding the object to be polished and the polishing pad against each other while supplying a polishing liquid containing abrasive grains between them.

  Conventionally, in a polishing process of a semiconductor substrate, as a method of holding an object to be polished, a wax method in which a workpiece is directly attached to wax, a non-wax method using the object to be polished, or the like (see, for example, Patent Document 1) ) Has been used. In the former, since the wax is directly brought into contact with the silicon wafer and fixed, it is necessary to remove the wax through a cleaning process after polishing, and it may take time for cleaning and may contaminate the wafer surface. On the other hand, in the latter, no chemicals are used and the adsorption action of the backing material is used, so there is no risk of contamination and it is not necessary to wash carefully. In addition, regarding the polishing of glass substrates, the demand for improving the performance of workpiece holders has increased in recent years as the size of glass substrates has increased.

  As shown in FIG. 4, a conventional example of a workpiece holder is a laminate in which a template (fiber reinforced thermosetting resin substrate) 1 and an elastic backing material 3 are bonded together using a thermoplastic adhesive material 2. It is what.

  The template 1 is subjected to hole processing for holding an object to be polished by a known processing method. The template 1 is bonded to the backing material 3 using a heat-sensitive adhesive material 2 made of a thermoplastic resin to form a laminate.

  The backing material 3 is manufactured by laminating by wet coagulation method on a substrate 4 such as a PET film, and has a foam layer having a fine opening on the surface, and by the adsorption action of the fine opening on the surface of the foam layer. Holds the workpiece.

However, when polishing is performed using the object holder shown in FIG. 4 manufactured by such a method, there are cases where peeling occurs at the interface between the template 1 and the heat-sensitive adhesive 2 depending on the polishing conditions. Therefore, measures such as increasing the thermocompression bonding temperature to suppress such peeling cause problems such as an increase in energy consumption and deterioration of the backing material 3 due to an increase in the thermocompression bonding temperature, and the temperature is increased by 10 ° C. However, it was found that sufficient effects could not be obtained. Moreover, in the conventional method, there is a large difference between the peel strength in the dry state and the peel strength in the wet state used in the actual polishing process, which is a design problem.
JP 2003-260660 A

  Therefore, the problem to be solved by the present invention is to increase the peel strength between the template and the heat-sensitive adhesive in each of the dry state and the wet state, and reduce the difference in the peel strength between the two states. It is to prevent peeling between the heat-sensitive adhesive and reduce the occurrence of defects in the object to be polished.

  An object holder according to the present invention is an object holder in which a template made of fiber reinforced resin and a backing material for holding an object to be polished are laminated using a thermoplastic adhesive, A primer layer is interposed between the thermoplastic adhesive and the thermoplastic adhesive.

  Preferably, the primer layer is an isocyanate prepolymer.

  More preferably, the template is either a glass fiber reinforced epoxy resin sheet or a fiber reinforced bakelite.

  Since the workpiece holder of the present invention increases the peel strength between the template and the heat-sensitive adhesive in both the dry state and the wet state, and reduces the difference in the peel strength in both states, It is possible to improve the holding performance of the object to be polished in the polishing process and contribute to the improvement of the polishing efficiency of the object to be polished.

  DETAILED DESCRIPTION Hereinafter, an object holding tool according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing a cross-sectional configuration of the workpiece holder. In FIG. 1, parts corresponding to those in FIG. Referring to FIG. 1, 1 is a template, 2 is a thermoplastic adhesive, 3 is a backing material, and 4 is a substrate such as a PET film.

  As a material of the template 1, fiber reinforced resin is used. As specific examples, a sheet made of glass fiber reinforced epoxy resin having excellent dimensional stability and low thermal expansibility, fiber reinforced bakelite, and thermosetting and heat. It is selected from the group consisting of a plastic polyester resin, a polyimide resin, a polysulfone resin, a polyparaphenylene resin, a fiber reinforced base material of a phenol resin, and the like.

  As the backing material 3, a material in which a polyurethane solution is applied to the base material 4 and then immersed in a coagulation tank to form a fine foam structure by a solidification reaction or a so-called nap structure is used.

  In the above configuration, the workpiece holder according to the embodiment is characterized in that the primer layer 5 is interposed between the template 1 and the thermoplastic adhesive 3.

  The formation of the primer layer 5 will be described. First, after degreasing the surface of the template 1 and applying the primer, the solvent is removed by air drying, and the heat-sensitive adhesive 2 is thermocompression bonded at 120 ° C., and further heated at 100 ° C. for 1 hour. Cured. Subsequently, the backing material 3 was laminated by thermocompression bonding at 120 ° C. to the heat-sensitive adhesive material 2.

  As a result of adopting the configuration in which the primer layer 5 is interposed between the template 1 and the thermoplastic adhesive 3 by the above method, the adhesive force between the template 1 and the heat-sensitive adhesive 2 is significantly larger than the conventional one. In addition, a remarkable improvement effect was observed, and there was almost no difference between the adhesive strength in the dry state and that in the wet state.

  In addition, it is preferable to use a polyisocyanate prepolymer as a primer. The polyisocyanate compound is a compound having two or more isocyanate groups in one molecule. For example, various isocyanate compounds such as aliphatic, aromatic, and alicyclic can be used. Specifically, the main component is a polyisocyanate prepolymer obtained by reacting TDI (tolylene diisocyanate), MDI (4,4-methylenephenyl diisocyanate), H-MDI (hydrogenated MDI) and a polyol. .

  The polyol used in the present invention is a compound having two or more hydroxyl groups in one molecule, such as ethylene glycol, propylene glycol, neopentyl glycol, diethylene glycol, polypropylene glycol, trimethylolpropane triethylene glycol, glycerin and the like. Other known polyol compounds can be used. In addition, polyester polyols obtained by condensation reaction of polyhydric alcohols and polybasic acids such as maleic acid, fumaric acid, adipic acid, terephthalic acid, sebacic acid, orthophthalic acid, and isophthalic acid can also be used.

  The molecular weight of the polyisocyanate prepolymer is preferably 500 to 10,000. The isocyanate is blended and reacted in an excess amount with respect to the polyol to synthesize an isocyanate prepolymer.

  A solution obtained by dissolving the above isocyanate prepolymer in a solvent such as ethyl acetate, butyl acetate, xylene, or toluene is used as a primer. The coating method can be performed using a known method such as a brush, a spray gun, or a roll coater.

  As the thermoplastic adhesive, at least one selected from the group consisting of thermoplastic adhesives such as acrylic, polyamide, polyolefin, polystyrene, polyvinyl chloride, and polyester, or a mixture or copolymer thereof is selected. The

  After degreasing the surface of the glass fiber reinforced epoxy resin template backing material and the side to be laminated with acetone, apply an isocyanate primer (Bernock D-750: manufactured by Dainippon Ink Industries, Ltd.) and air dry. Then, the solvent was volatilized and further heat-cured at 100 ° C. for 1 hour. Next, an acrylic thermoplastic adhesive was pressure-bonded to the treated surface through a heat roll set at 120 ° C., and then a holding hole for holding an object to be polished was formed by end milling. Furthermore, a backing material was thermocompression-bonded to the adhesive surface at 120 ° C. to prepare a workpiece holder.

  Three test pieces were cut out from the obtained workpiece holder, and the adhesive strength was measured according to JIS K68 54-2. In the test under wet conditions, the sample was immersed in a slurry solution (Nalco 2350: manufactured by Nalco, pH 10.5) at 50 ° C. for 24 hours, and then the adhesion rate was measured. FIG. 2 shows adhesion data under wet conditions, and FIG. 3 shows the adhesion strengths under wet conditions and dry conditions side by side.

(Comparative Example 1)
Without using a primer, a heat-sensitive adhesive was pressure-bonded to the template at 125 ° C., and the subsequent process produced a workpiece holder under the same conditions as in Example 1. Three test pieces were cut out from the obtained workpiece holder and the adhesive strength was measured using the method described in Example 1.

(Comparative Example 2)
A test piece was produced under the same conditions as in Comparative Example 1 except that the pressure bonding temperature was 130 ° C., and the adhesive strength was measured.

(Comparative Example 3)
A test piece was prepared under the same conditions as in Comparative Example 1 except that the pressure bonding temperature was 120 ° C., and the adhesive strength was measured (current conditions). The adhesive strength in the dry condition was 0.7 kg / inch, whereas that in the wet condition was significantly reduced to 0.4 kg / inch.

 Table 1 shows the adhesive strength data.

  Explaining Table 1, the current conditions are the conditions used in Comparative Example 3, and the adhesive strength obtained under these conditions is not shown in Table 1. Comparative Example 1 is 5 ° C. higher than the current conditions and the bonding temperature is 125 ° C., and Comparative Example 2 is 10 ° C. higher than the current conditions and the bonding temperature is 130 ° C.

FIG. 1 is a diagram showing a cross-sectional structure of a workpiece holder according to an embodiment of the present invention. FIG. 2 is a table showing the results of measurement of adhesive strength under wet conditions. FIG. 3 is a table showing the results of measurement of adhesive strength under dry conditions and wet conditions. FIG. 4 is a view showing a cross-sectional structure of a conventional workpiece holder.

Explanation of symbols

1 ... template,
2 ... heat sensitive adhesive,
3 ... backing material,
4 ... PET layer,
5 ... Primer

Claims (3)

  A polishing object holder in which a template made of fiber reinforced resin and a backing material for holding an object to be polished are laminated using a thermoplastic adhesive, and a primer layer is provided between the template and the thermoplastic adhesive. A polished object holder characterized by being interposed.   The workpiece holder according to claim 1, wherein the primer layer is an isocyanate prepolymer.   The polished article holder according to claim 1 or 2, wherein the template is either a glass fiber reinforced epoxy resin sheet or a fiber reinforced bakelite.

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