JPH0936216A - Antistatic wafer carrier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the adhesion of dirt and dust to a wafer carrier by static electricity by molding a resin composed of a polyether etherketon resin and conductive carbon black mixed with each other at a specific mixing ratio as an abrasion mass having a specific abrasion resistance for Taber abrasion tests. SOLUTION: A composite material is prepared by mixing 70-97wt.% polyether etherketon resin and 30-3wt.% conductive carbon black. The abrasion mass of the composite resin material for Taber abrasion tests is adjusted to 3-5mg so as to obtain a resin having an excellent abrasion resistance. Therefore, the adhesion of dirt, dust, etc., to a wafer carrier by static electricity can be eliminated and the dusting characteristic, heat resistance, mechanical characteristic, and dimensional accuracy of the carrier can be improved and the weight of the carrier can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer carrier used for processing, transporting and storing wafers made of silicon or the like handled in the semiconductor industry.

[0002]

2. Description of the Related Art Conventionally, in a heat treatment process for a wafer, a carrier made of aluminum, a polyether ether ketone resin (hereinafter abbreviated as PEEK resin) having high heat resistance, or a carrier made of a fluorine resin has been used. But,
The technological progress in the semiconductor industry has been remarkable, and the degree of integration of integrated circuits on one chip has increased dramatically. Along with this, the minimum line width of the circuit has also become very narrow.
Dust, dust, etc. of a size that was not a problem even if it adhered to the wafer in the past caused defects, and the chips in that part became unusable, product yield and production efficiency,
There are problems such as extremely poor productivity. Therefore, it is required that the carrier used for processing, transporting, and storing the wafer is also a material that has low dust generation and does not easily adhere to dust and dust.

[0003]

However, the carrier made of aluminum is a metal and is a conductor, so that it does not have dust and the like attached to it, but it has a high specific gravity. It has the drawback of being overloaded. Since the conventional carrier made of PEEK resin is an insulator, it is charged with static electricity due to friction or the like and attracts foreign particles floating around and adheres to the surface of the wafer. As the resin having high heat resistance, polyether sulfone resin (hereinafter abbreviated as PES resin), polyarylate resin (hereinafter abbreviated as PAR resin), nylon resin (hereinafter abbreviated as PA resin), polyphenylene sulfide resin ( Hereinafter, PPS resin), perfluoroalkoxy-substituted polytetrafluoroethylene resin (hereinafter abbreviated as PFA resin), and the like, and conductive carbon black for imparting conductivity to PES resin, PAR resin, and PFA resin. However, carbon black has a drawback that the abrasion resistance is poor and the carbon black easily falls off. P
Although the resin A to which the conductive carbon black is added is excellent in abrasion resistance, it has a defect that the rigidity is weak under high temperature and the carrier is deformed. The PPS resin to which conductive carbon black is added has excellent abrasion resistance, but has drawbacks such as burrs on the molded product, brittleness and cracking.

[0004]

Means for Solving the Problems The inventors of the present invention have made earnest studies to solve the above-mentioned problems. As a result, PEEK resin containing conductive carbon black has an excellent antistatic effect and does not cause carbon loss. The inventors have found that the present invention provides a wafer carrier having excellent heat resistance and reached the present invention. That is, the present invention provides a polyetheretherketone resin 7
0 to 97% by weight, and conductive carbon black 3 to 30
It is an antistatic wafer carrier obtained by molding a resin composition comprising a resin composition comprising 1 wt% and having a wear resistance of 3 to 50 mg in a Taber-type wear test and having excellent wear resistance. .

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION A wafer carrier having conductivity according to the present invention is manufactured by a composite material in which a conductive carbon black is mixed with PEEK resin having a repeating unit represented by the following formula (1).

[0006]

Embedded image

The composition ratio of the PEEK resin of the present invention and the conductive carbon black is 70 to 97% by weight of the PEEK resin,
The conductive carbon black is 3 to 30% by weight, preferably the PEEK resin is 80 to 95% by weight, and the conductive carbon black is 5 to 20% by weight. If the conductive carbon black is less than 3% by weight, preferable conductivity cannot be obtained, and
If it exceeds 5% by weight, moldability is poor.

The PEEK resin used in the present invention has an inherent viscosity of 0.
The range of 65 to 0.95 dl / g is used, and the range of 0.74 to 0.90 dl / g is preferably used. If it is less than 0.65 dl / g, the mechanical strength of the wafer carrier will be insufficient, and if it exceeds 0.95 dl / g, the fluidity will be poor and the moldability of the wafer carrier will be poor. The logarithmic viscosity is defined by the following formula (2), and is measured by an Ostwald viscometer under the condition of 30 ° C. after dissolving the polymer in 98% concentrated sulfuric acid. Logarithmic viscosity = 1 n (t / t ₀ ) / C (2) t: Drop time of sample solution t ₀ : Drop time of concentrated sulfuric acid C: Sample concentration 0.1 g / dl

The conductive carbon black in the present invention is one which, when filled in a resin, imparts conductivity and greatly reduces the surface resistance value of the resin, and acetylene black and furnace black are preferably used. . The furnace black is specifically Ketjen Black EC (trade name of Akzo Co., Netherlands), Asahi HS-
There are commercial products such as 500 (trade name of Asahi Carbon Co., Ltd.) and Colombian carbon N-550U (trade name of Colombian Carbon Co., USA).

The abrasion mass of the resin composition of the present invention in the Taber abrasion test is in the range of 3 to 50 mg, preferably 3 to 20 mg. If it exceeds 50 mg, carbon will easily fall off due to friction or the like. What is the wear mass? The mass of the test piece before the test is accurately measured to 1 mg, and after using the Taber type wear tester, the test piece is tested under the condition of the wear wheel CS-17, the load of 1 kgf, and the rotation speed of 1000 rpm. Was determined from the difference between the mass before measurement and the mass before the test, and was measured by the method according to ASTM D1044.

The method for producing the conductive resin composition of the present invention is not particularly limited, and a generally known method can be adopted. That is, PEEK resin and conductive carbon are uniformly mixed using a mixer such as a tumbler, and then melt-kneaded and pelletized by a uniaxial or multiaxial extruder having a sufficient kneading capacity. In addition, conductive fillers such as carbon fibers, mica with conductivity, talc, whiskers and the like may be added within a range where abrasion resistance does not decrease.

The method for molding the conductive wafer carrier of the present invention is not particularly limited, and a generally known method can be adopted. For example, an injection molding method, a compression molding method, etc. can be mentioned.

The shape of the wafer carrier used in the present invention is not particularly limited, but it may be, for example, one having two opposed panels having a plurality of grooves for separating and supporting a plurality of wafers. . The electroconductive wafer carrier of the present invention has features such as excellent wear resistance, heat resistance and mechanical properties, particularly good dimensional accuracy, light weight, and high rigidity maintained even at high temperatures.

[0014]

EXAMPLES The present invention will be described in more detail with reference to the following examples. The resin compositions described in Examples and Comparative Examples and the special evaluations of the wafer carriers molded by the resin compositions were performed according to the following methods. (1) Surface resistance (conductivity) A wafer carrier was molded by injection molding, and the surface of the molded product was measured with a surface resistance meter (Mitsubishi Yuka Co., Ltd., trade name Hiresta), and 10 ¹² Ω or less was passed. . (2) Melt flow index (molding workability) Based on JIS-K7210. Load 10kg, temperature 4
When a wafer carrier is molded by 00 ° C injection molding,
When the melt flow index was 2.0 or less, molding could not be performed. (3) Abrasion resistance (carbon loss) A disk with a thickness of 5 mm and a diameter of 120 mm was formed by injection molding, and measured with a Taber abrasion tester under the conditions of an abrasion wheel CS-17, a load of 1 kgf, and a rotational speed of 1000 rpm. The wear mass was determined. (4) Impact resistance (mechanical strength) A wafer carrier is molded by injection molding and the height is 0.75.
drop the wafer carrier from m to the concrete floor,
Those that did not break were considered acceptable (◯), and those that damaged were rejected (x).

Examples 1-2 PEEK resin VICTREX PEEK 450P
[Manufactured by Victrex Co., England, 0.86 dl /
g], Ketjen Black EC as conductive carbon
[Netherlands: Akzo] was mixed in the ratio shown in Table 1,
It was kneaded and pelletized in the range of 360 to 400 ° C. with a 35 mmφ twin-screw extruder. The pellet clamping force is 200 to
n injection molding machine at a temperature of 400 ℃, mold temperature 170
A wafer carrier was molded under the conditions of ° C and an injection pressure of 1500 kg / cm ² . The evaluation results of this molded product are shown in Table 1.
It was excellent in antistatic properties and impact resistance, had little carbon loss, and had a sufficient practical value.

Examples 3 to 4 Colombian carbon N-550 as conductive carbon
The same procedure as in Examples 1 and 2 was carried out except that U (manufactured by Colombian Carbon Co., USA) was used in the proportion shown in Table 1. Table 1 shows the evaluation results.

Example 5 In Example 1, as PEEK resin, logarithmic viscosity of 0.
Same as Example 1 except that 68 dl / was used. Table 1 shows the evaluation results.

Comparative Example 1 The same as in Examples 1 and 2 except that the mixing ratio of Ketjen Black EC was changed. The results are shown in Table 2. When the compounding ratio defined in the present invention is deviated, the conductivity is significantly reduced,
The antistatic effect is not seen and it does not have sufficient practical value.

Comparative Example 2 In Examples 3 to 4, Columbian Carbon N-55 was used.
The same was done except that the compounding ratio of 0 U was changed. Table 2 shows the results
Shown in The moldability was significantly reduced, and the wafer carrier could not be molded.

Comparative Example 3 The same procedure as in Example 1 was repeated except that the PEEK resin used in Example 1 had a logarithmic viscosity of 0.60 dl / g. Table 2 shows the results. The mechanical strength is insufficient and the wafer carrier drops from a height of 0.75 m onto the concrete floor, resulting in damage, which does not have sufficient practical value.

Comparative Example 4 The procedure of Example 1 was repeated, except that the PEEK resin used in Example 1 had a logarithmic viscosity of 0.98 dl / g. Table 2 shows the results. The moldability was significantly reduced, and the wafer carrier could not be molded.

Comparative Example 5 In Example 1, the PEEK resin was replaced with the PFA resin PFA.
340-J [Mitsui. Manufactured by DuPont Fluorochemicals]
Example 1 was repeated except that the kneading temperature 360 to 400 ° C was changed to 300 to 350 ° C and the injection molding temperature 400 ° C to 320 to 350 ° C. Table 2 shows the results. There is much carbon loss and it does not have sufficient practical value.

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

[Table 3]

[0026]

[Table 4]

[0027]

[Table 5]

[0028]

The antistatic wafer carrier of the present invention is free of dust and dirt due to static electricity, has low dust generation, is excellent in heat resistance and mechanical properties, has good dimensional accuracy, and is lightweight, and is of practical value. large.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyasu Daichi 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemical Co., Ltd.

Claims (2)

[Claims] 1. Polyether ether ketone resin 70-9
7% by weight, and conductive carbon black 3 to 30% by weight
An antistatic wafer carrier obtained by molding a resin composition comprising a resin composition having excellent wear resistance of 3 to 50 mg in a Taber type abrasion test. 2. The logarithmic viscosity of the polyetheretherketone resin is in the range of 0.74 to 0.90 dl / g.
An antistatic wafer carrier as described in.