JP2000042909A - Holding material for member to be polished and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a holding material having strong separating strength, and a long time usableness, by laminating in order a thermal plastic resin layer including the compositions of a supporter and a wet foam layer and the wet foam layer on the supporter. SOLUTION: A holding material strong in separating strength can be obtained by laminating in order a thermal plastic resin layer including the compositions of a supporter and a wet foam layer and the wet foam layer on the supporter. Moreover the supporter - the thermal plastic resin layer - the wet foam layer can be made to firmly adhere with each other, to obtain the holding material having separating strength sharply exceeding 2000 g/25 mm, by using polyester- polyurethane copolymer as the thermal plastic resin layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a semiconductor wafer,
The present invention relates to a holder for a member to be polished such as a liquid crystal glass.

[0002]

2. Description of the Related Art In general, when a semiconductor wafer is polished by a polishing machine such as a rotary processing machine, the wafer is fixed to a surface plate of the polishing machine, and is arranged to face the surface plate. The polishing cloth is rotated relative to the set surface plate,
The wafer surface is polished by supplying a polishing liquid containing abrasive grains and the like between the two.

At this time, a method of holding the wafer on the ceramic plate for polishing includes a wax method in which wax is applied to one side of the wafer and the wafer is fixed to the ceramic plate, and a method in which the wafer is bonded with water using a holding material made of a porous resin. There is a waxless method to do.

[0004] The wax method is a major obstacle to automation because a wax removal operation is required as a post-process.
In this regard, the waxless method is excellent. It is widely known that the waxless method is not only for holding a wafer on a ceramic plate for polishing, but also for polishing and polishing one side such as a glass for liquid crystal using a similar holding material as a holding material for a non-abrasive body. Have been.

[0005] The support used in these methods is generally produced by wet coagulation using a urethane resin composition.
In this wet coagulation method, after a urethane resin composition is prepared, the urethane resin composition is applied to a support, and then wet coagulation is performed in a mixed solution of water and dimethylformamide (DMF) to form a foam on the support. A layer is formed and then dried, and in some cases, the outermost surface is buffed to obtain a holding material.

[0006]

SUMMARY OF THE INVENTION Such a holder is
Generally, a polyester sheet is used in view of dimensional stability and thickness uniformity, but the bonding force with urethane is weak, and peeling occurs immediately as it is.

In JP-A-2-88229, a urethane polymer is mixed with a vinyl chloride polymer, a vinyl chloride-vinyl acetate copolymer, and a vinyl polymer composed of vinyl chloride-vinyl acetate-vinyl alcohol, and the mixture is formed on a support. A holding material characterized by being provided directly has been proposed.

However, urethane-vinyl chloride polymers have poor compatibility, are easily separated, and are difficult to produce industrially. In addition, the peel strength is 650 g / 25 mm.
Although the above is described, at least 2000 g / 25 mm may be used for a total of 100 hours in practical use.
The above peel strength is required.

For this reason, as a holding material, a holding material having a polyurethane porous layer firmly bonded to a polyester sheet is required.

[0010]

Means for Solving the Problems The present inventors have intensively studied in view of the above problems and completed the results. The object of the present invention is to provide a holding material which has a strong peeling strength and can be used for a long time. To provide.

The above object is achieved by sequentially laminating a thermoplastic resin layer containing the composition of the support and the composition of the wet foam layer, and the wet foam layer on the support. Examples of the support used in the present invention include a vinyl chloride sheet, a polypropylene sheet, and a polyester sheet, and a polyester sheet is preferable from the viewpoint of dimensional stability and thickness uniformity.

As the thermoplastic resin laminated on the support, both the adhesion to the support and the adhesion to the upper polyurethane wet foam layer must be firmly adhered.

Although the polyester resin strongly adheres to the polyester sheet due to the similarity of its structure,
There is a problem in adhesion to the upper polyurethane wet layer. On the other hand, although the polyurethane resin strongly adheres to the upper polyurethane wet layer, it has a problem in the adhesive strength between the polyester sheets.

However, by using the polyester-polyurethane copolymer for the thermoplastic resin layer, the support, the thermoplastic resin layer, and the wet foam layer are firmly adhered to each other.
A peel strength significantly exceeding 2000 g / 25 mm is obtained.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The composition ratio of the polyester-polyurethane copolymer is not particularly limited as long as they are mutually present, but is preferably 20:80 to 8 in molar ratio.
0:20.

The support used in the present invention includes a vinyl chloride sheet, a polypropylene sheet, a polyester sheet, etc., and has low water absorption, good dimensional stability when wet, excellent chemical resistance to polishing liquid, and thickness accuracy. In general, a polyester sheet having high surface smoothness and excellent surface smoothness is used. Preferable is Crispar G1212 '(manufactured by Toyobo Co., Ltd.).

In the thermoplastic resin layer of the present invention, a copolymer of polyurethane with vinyl chloride, polypropylene, polyester or the like is important from the viewpoint of mutual adhesion strength. For example, as a commercially available product, “Vylonal UR-1400” (manufactured by Toyobo Co., Ltd.) may be mentioned.

In order to adjust the above-mentioned composition to an appropriate coating viscosity on a support in advance, the composition is diluted with a solvent such as methyl ethyl ketone and coated on the support with a reverse coater, knife coater or the like. Thereafter, the solvent is completely removed at 80 ° C to 120 ° C. The thickness of the thermoplastic resin layer is not particularly limited, but if it is too thin, the adhesive effect is not sufficiently exhibited, and if it is too thick, there is a risk of impairing the performance as a holding material due to uneven thickness. Preferably it is 30 to 60 μm.

The urethane composition used in the present invention includes:
It generally comprises an organic diisocyanate, a polyol and a chain extender.

Examples of the organic diisocyanate include diphenylmethane-4,4'-diisocyanate, xylylenediisocyanate, dichlorohexylmethane-4,
Examples thereof include 4 'diisocyanate and hesamethylene diisocyanate, and mixtures thereof.

As the polyol, polyethylene adipate glycol, polypropylene adipate glycol, polyethylene propylene adipate glycol,
Polyester polyols such as polybutylene adipate glycol, polyethylene butylene adipate glycol, polypentamethylene adipate glycol, or polyether polyols such as polyethylene ether glycol, polypropylene ether glycol, polytetramethylene ether glycol, or lactone ring opening Examples of the polymerized polycaprolactones include glycols having a hydroxyl group at both terminals and a molecular weight of 500 to 8000, or polyhexamethylene carbonate, and those obtained by combining and copolymerizing polyhexamethylene carbonate and the above-mentioned polyols.

Examples of the chain extender include low molecular weight compounds containing an active hydrogen group, for example, glycols such as ethylene glycol, propylene glycol, butylene glycol, and diethylene glycol; for example, diamines such as ethylene diamine, propylene diamine, and butylene diamine; Alternatively, amino alcohol and the like can be mentioned.

Examples of the solvent for dissolving the urethane composition having the above composition include water-miscible organic solvents such as dimethylformamide, dimethylsulfoxide, etrahydrofuran, dimethylacetamide, ethyl acetate and dioxane. It is not particularly limited to these.

The solid content concentration of the urethane composition is preferably from 10 to 40% by weight, more preferably from 15 to 30% by weight.
It is. If the solid content concentration is too low, large undulations will occur on the surface of the urethane layer after wet coagulation, and the smoothness will deteriorate. On the other hand, if the solid content is too high, air is easily entrained, and large depressions may occur on the urethane surface after wet solidification.

The urethane composition adjusted to the above composition is coated on the already coated thermoplastic resin layer by using a suitable coating means such as a reverse coater or a knife coater. The coating amount is not particularly limited, but is preferably 150 g to 1200 g / m ² .

Then, after wet coagulation in a mixed solution of water and DMF (dimethylamide), washing with water is performed to remove the solvent.
By drying, a foam layer is obtained on the coat layer.

The surface of the obtained holding material can be used as it is as a holding material, and in the case of liquid crystal glass, the glass is fixed to the holding material by the surface tension of water and polished.

Further, the surface of the holding material is coated with, for example, sandpaper, preferably # 120 to # 320 sandpaper, with a clearance of 0.3 to 0.6 mm, a line speed of 1 to 10 m / min, and a paper rotation speed of 500. ~ 30
Buffing is performed under the condition of 00 rpm.

In the case of a silicon wafer, using a holding material that has been surface-treated as described above, a template mainly made of glass-containing epoxy resin that is opened to the size of the wafer is arranged, and a non-polished material is placed in the template. A certain silicon wafer is polished by absorbing water.

[0030]

EXAMPLES Hereinafter, the product of the present invention will be described in detail with reference to Examples and Comparative Examples. In the Examples and Comparative Examples, “parts” and “%” are used.
“% By weight” is a percentage by weight and “% by weight” is a percentage by weight per unit weight unless otherwise specified.
Means Measuring method of peel strength The holding material was cut into a rectangular shape of 25 mm x 100 mm, and this was used as a test piece. A urethane-based adhesive is applied to two test pieces with a 10 mm gripping margin left, and adheres to each other. Next, the adhered test piece was fixed to Tensilon U-1798 (manufactured by Orientec Co., Ltd.), and the relative strength was 10
Pull at a speed of 0 mm / min and measure its strength. The evaluation of the peeling strength of the holding material was performed by calculating the actual measurement value (g / 25 mm) and considering the severe use environment of the holding material.
At least 00 g / 25 mm was evaluated as ○, and less than 00 g / 25 mm was evaluated as ×. Examples 1 to 3 The molar ratio of polyester: polyurethane was 80: 20,5.
The ratios were adjusted to 0:50 and 20:80 to obtain the respective polyester-polyurethane copolymers of Examples 1, 2, and 3.

The polyester-polyurethane copolymer was diluted with methyl ethyl ketone to adjust the solid content to 25%, and the clearance was adjusted to 0% with a knife coater on a polyester sheet (manufactured by Toyobo Co., Ltd., 'Crisper G1212 (0.188 mm thick)). .15 mm. Thereafter, the sheet was dried at 80 ° C. for 15 minutes to obtain a sheet coated with a thermoplastic layer having a thickness of about 35 μm.

On the other hand, using polytetramethylene ether glycol (PTMG) as a polyol component, diphenyl-4,4'-diisocyanate and diamine are solution-polymerized in dimethylformamide to obtain a polyurethane elastomer solution having a concentration of 30%. Was. 100 parts of this polyurethane elastomer solution, 3 parts of carbon black powder,
Stearyl alcohol 3 parts, dimethylformamide 10
0 parts were added to obtain a coating solution.

After applying the obtained coating solution to the above sheet at 600 g / m ² with a reverse coater, the coating solution is coagulated in a coagulation bath (water: dimethylamide = 90: 10 weight ratio) at 35 ° C. Then, hot air drying was performed at 150 ° C. to obtain a holding material having a thickness of 0.6 mm. Comparative Example 1 Example 1 was repeated except that a polyester resin (without polyurethane resin) having the same composition was used on a polyester sheet.
A holding material was produced in the same manner as in Nos. 1 to 3. Comparative Example 2 Example 1 was repeated except that a polyurethane resin (containing no polyester resin) having the same composition was used on a polyester sheet.
A holding material was produced in the same manner as in Nos. 1 to 3.

The peel strength of each of the produced holding materials was measured using a Tensilon U-1798 apparatus. The results are shown in Table 1. As is clear from the examples, the holding material using the polyester-polyurethane copolymer for the polyester sheet has a remarkably increased peel strength, and is a tough holding material.

[0035]

[Table 1]

[0036]

The obtained holding material has a peel strength of 2000.
The holding material had a g / 2.5 mm or more and was sufficiently usable for long-time processing.

Claims (5)

[Claims] 1. A holding material for a member to be polished, wherein a thermoplastic resin layer containing a composition of a support and a composition of a wet foam layer, and a wet foam layer are sequentially laminated on the support. 2. The holding material according to claim 1, wherein the support is made of polyester. 3. The holding material according to claim 1, wherein the thermoplastic resin layer is a polyester-polyurethane copolymer. 4. The holding material according to claim 1, wherein the wet foam layer mainly comprises a polyurethane resin. 5. A method for producing a holding material according to claim 1.