JPH09315485A - Chemical and heat-resistant container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To retain a necessary strength and appearance for a long period of time even if a container is cleaned at a high temperature, by forming a hydrofluoric acid-cleaning resistant container with carbon fiber and polyarylene sulfide resin. SOLUTION: This container which can be effectively used on washing silicon wafers with hydrofluoric acid, is made of carbon fiber and polyarylene sulfide resin (PAS resin). This PAS resin is a polymer including a repeating unit of 70 or more mol% shown by a formula [ -Ar -S- ] for instance (-Ar- in the formula shows a divalent aromatic group including at least one 6C-membered ring). In this case, it is preferable that the contained ratio of carbon fiber be 3-60wt.% and curved pitch carbon fiber is used for the carbon fiber. It is preferable that short fiber be used for the carbon fiber and it is perticularly preferable that curved fiber be used in the short fiber. It is preferable that pitch carbon fiber produced by the vortex flow method be used for instance.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a cleaning container excellent in heat resistance and chemical resistance. This container is particularly useful as a container used for hydrofluoric acid cleaning of silicon wafers.

[0002]

2. Description of the Related Art In recent years, the processing speed of computers has become higher and capacity has been increased, home appliances and electric appliances have become more sophisticated, battery technology innovations used for electric cars and portable telephones, etc., and electrons used for mobile vehicles Technology, the spread of in-house power generation system with FAX communication field, energy saving, and further, with the rapid progress of electronic semiconductor application technology used in aerospace field, a chip for microprocessor used for them,
Demand for semiconductor wafers, in particular silicon wafers, which are materials for memory chips and solar cell chips, is increasing more and more.
High purification is required.

[0003] Many of these products use a chip in which a complex electronic circuit is embedded on the surface of a silicon wafer, and when incorporating this complex circuit, a general method is to carry out chemical cleaning of the silicon wafer surface. It has been

As this chemical cleaning method, generally known is a method of cleaning a plurality of times in several kinds of acid and alkali cleaning solutions, and the types of these acid cleaning solutions include concentrated sulfuric acid, hydrochloric acid, hydrofluoric acid, etc. Sodium hydroxide solution etc. are known as a kind of alkaline washing | cleaning liquid. Conventionally, when cleaning silicon wafers with these chemicals, they are placed in a container made of titanium alloy or plastic and cleaned with these chemicals.

However, since the container made of titanium alloy is made of metal, it is heavy and expensive. Also, if plastic containers are used, reinforcements that make up the containers,
Since the heat resistance and chemical resistance performance differs depending on the type of plastic, different containers are used for different types of cleaning chemicals.

Although the above plastic container is intended to reduce the weight and cost as compared with those made of titanium alloy, the conventional method may require container change depending on the kind of cleaning chemical, and this container transfer is necessary. Is a cause of generation of a slight damage of the object to be cleaned and a decrease in purity, and is also a cause of inhibition of shortening of the cleaning time.

Recently, improvements have been required for maintaining high purity, shortening the washing time for improving productivity, making the washing conditions more severe, and further reducing the cost as compared to the prior art, and improving these problems As a method, a method of using a container having a glass fiber and various fillers as a reinforcing material and a resin having excellent heat resistance and chemical resistance as a base material is considered promising.

[0008]

SUMMARY OF THE INVENTION Molded articles using these materials are useful for known cleaning chemicals at ordinary temperature, but glass fibers are inferior in acid resistance, especially at high temperatures, particularly at 80 ° C. or higher, The washing container using the fiber is not suitable when using a hydrofluoric acid washing chemical at high temperature, and in this case, it has been necessary to transfer it to another container excellent in acid resistance. In other words, it is excellent in acid resistance at high temperature, and it is not necessary to transfer to the other washing chemicals (concentrated sulfuric acid, hydrochloric acid, sodium hydroxide solution) and washing conditions.
There was a need for lighter containers for cleaning.

[0009]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned object, and the gist of the invention is a container for cleaning acid-proof acid, which comprises carbon fiber and polyarylene sulfide resin. The present invention will be described in detail below.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION As the polyarylene sulfide resin (hereinafter referred to as "PAS resin") used in the present invention, any of known and commonly used resins can be used.
A polymer containing 70 mol% or more of a repeating unit represented by the general formula [-Ar-S-] (wherein -Ar- represents a divalent aromatic group containing at least one carbon six-membered ring) is It can be mentioned.

Representative substances of PAS resin are represented by the structural formula [-φ
A polymer containing 70 mol% or more of a repeating unit represented by -S-] (wherein -φ- represents a phenylene group) is a so-called PPS resin.

PAS resins generally have a molecular structure which is substantially linear and does not have a branched or crosslinked structure, and a resin having a branched or crosslinked structure.
In the present invention, both types are effective.

A preferred PAS resin for use in the present invention is a PPS resin containing 70 mol% or more of a repeating unit represented by a repeating unit [-.phi.-S-] (wherein -.phi.- is a phenylene group).

When the repeating unit is 70 mol% or more, the crystallinity as a characteristic of a crystalline polymer tends to be high, sufficient strength tends to be obtained, and toughness and chemical resistance become excellent. There is a tendency.

This PP suitably used in the present invention
The S resin may contain less than 30 mol% of other copolymer building blocks. Representative examples of the constituent unit which may be contained include, for example, meta-phenylene sulfide unit, diphenyl ketone sulfide unit, diphenyl sulfone sulfide unit,
A diphenyl ether sulfide unit, a 2, 6- naphthalene sulfide unit, a trifunctional unit etc. are mentioned. Among these, the trifunctional unit is preferably 1 mol% or less from the viewpoint of not reducing the crystallinity.

As the carbon fiber used in the present invention, known and commonly used ones can be used, but in general, cellulose fiber,
A variety of fibers can be used, such as flame-retardant, carbonaceous, graphitic and the like obtained by firing fibers made of acrylic fibers, lignin fibers, petroleum-coal-based special pitches, etc., or vapor grown carbon fibers.

The carbon fiber is preferably a short fiber, and among the short fibers, a curved one is particularly preferable. As a short fiber of curved carbon fiber, the aspect ratio of one fiber is 50
In the above, those having a large specific volume as compared with the straight carbon fiber, specifically those having a specific volume of 9 cm ³ / g or more when converted to an aspect ratio of 500, are particularly preferable. Pitch-based carbon fibers are suitable.

The length of the carbon fiber contained in the molded product is not particularly limited because the length varies depending on the molding method, but generally 0.1 to 1 mm when the molded product is obtained by injection molding
Those having long carbon fibers can obtain high mechanical strength. The carbon fiber preferably has a diameter of about 30 μm or less in order to disperse it uniformly.

As a type of carbon fiber, those using pitch-based curved carbon fiber have a small difference in flow direction and flow perpendicular direction in shrinkage ratio after injection molding, and therefore, a product requiring high accuracy can be obtained. It is advantageous to

The molded article in the present invention may contain carbon fiber, but it is usually blended so as to be 3 to 60% by weight. If the carbon fiber content is less than 3% by weight, the reinforcing effect by the carbon fiber is small, and if it exceeds 60% by weight, the flowability at the time of molding becomes poor, which is not preferable.

In addition, a mold corrosion inhibitor and a mold release wax may be added as appropriate.

As mold corrosion inhibitors, for example, carbon dioxide
Lead, manganese carbonate, magnesium carbonate, particulate oxide
Lead, hydrotalcite (Mg_0.7.Al_0.3(OH)_{2 ·}CO_{3 · 0.55}H
₂O), metal solid solution (Mg)_{0.4 ·}Zn_{0.3 ·}Al (OH)₂(CO₃)_{0.15 · 0.55}H
₂O, Mg_0.5.Pb_0.22.Al_0.28(OH) _{2 ·}I_{0.28 · 0.16}H₂O), etc.
As a mold release wax, for example, polyolefin wax
S, carnauba wax, hydrocarbon wax, silicone
And fluorocarbon waxes.

As a method of preparing these materials, each component may be uniformly mixed by the usual heating and kneading means, and generally, various kinds of heating and kneading means, such as a single screw extruder, a twin screw extruder, etc. There is a method of pelletizing the above-mentioned material using an extruder of type B. As a method of molding into a container according to the present invention using pellets obtained by such a method, it is general to mold using a known injection molding machine or extruder, but in some cases each material is injected Direct molding may be performed using a molding machine, an extrusion molding machine or the like. The heating temperature is suitably 280 to 400 ° C. for injection molding and extrusion molding at the time of pellet production.

The present invention includes the following embodiments. 1. A container for cleaning acid-proof acid comprising carbon fiber and polyarylene sulfide resin. 2. The container for cleaning with a hydrofluoric acid according to 1 above, wherein the content of carbon fibers is 3 to 60% by weight. 3. The container for boiling acid resistant cleaning as described in any one of 1 or 2 above, wherein the carbon fiber is a pitch-based bent carbon fiber. 4. 5. The container for cleaning with acid-resistant acid according to any one of 1 to 3 above, wherein the container for cleaning is a container for cleaning silicon wafer.

[0025]

EXAMPLES The present invention will be described based on the following examples.

Example 1 80% by weight of polyphenylene sulfide resin (manufactured by Dainippon Ink and Chemicals, Inc.) and pitch-based curved carbon fiber donacarbo S-242 [pitch-based carbon fiber as carbon fiber:
Made by Donac Co., Ltd., average diameter 13 μm, aspect ratio 1
8) and 20% by weight, other trace amounts of mold corrosion inhibitor and mold release wax were mixed and homogeneously mixed, and then pelletized at a cylinder temperature of 290 to 310 ° C. in a single screw extruder.

The pellets were molded using an injection molding machine under the conditions of a cylinder temperature of 290 ° to 310 ° C. and a mold temperature of 150 ° C. to obtain a molded body in which carbon fibers were homogeneously dispersed. The shrinkage factor of this molded article after molding was 1.4% in the flow direction and 1.1% in the perpendicular direction, and no warpage of the molded article was observed. There was no change in appearance of this container after immersion for 1000 hours in a hydrofluoric acid solution in which this molded product was heated to 100 ° C., and the flexural strength retention rate under the same conditions was 100%. . The silicon wafer cleaning container obtained by injection molding the pellets and capable of aligning and holding the silicon wafer and not holding the cleaning liquid inside the container was extremely excellent in heat resistance and chemical resistance.

EXAMPLE 2 Instead of the carbon fibers in Example 1, pitch-based bent carbon fibers Dona Carbo S-244 [pitch-based carbon fibers:
Made by Donac Co., Ltd., average diameter 13 μm, aspect ratio 5
5] is 40% by weight, and a mixture formulated to be
Pelletization was performed at a cylinder temperature of 290 to 310 ° C. by a twin-screw extruder.

The pellets were injection molded as a material to obtain a container for cleaning silicon wafers of the present invention in which carbon fibers are uniformly dispersed. Similarly to Example 1, the shrinkage ratio of the molded article after molding was 1.4% in the flow direction and 1.1% in the perpendicular direction, and no warpage of the molded article was observed. There was no change in appearance of this container after immersion for 1000 hours in a hydrofluoric acid solution in which this molded product was heated to 100 ° C., and the flexural strength retention rate under the same conditions was 100%. .

EXAMPLE 3 Instead of the carbon fiber in Example 1, PAN-based carbon fiber Vesphyt HTA-C6S [Toho Rayon Co., Ltd.]
Production: A mixture prepared using a diameter of 7 μm and an aspect ratio of 860] at 20% by weight was pelletized at a cylinder temperature of 290 to 310 ° C. in a twin-screw extruder.

The pellets were injection molded as a material to obtain a container for cleaning silicon wafers according to the present invention in which carbon fibers are uniformly dispersed. The shrinkage factor of this molded article after molding was 2.2% in the flow direction and 0.8% in the perpendicular direction, and warpage of the molded article was observed. There was no change in appearance of this container after immersion for 1000 hours in a hydrofluoric acid solution in which this molded product was heated to 100 ° C., and the flexural strength retention rate under the same conditions was 100%. .

Comparative Example 1 Microglass as Glass Fiber JAFT-104
[Asahi Fiber Glass Co., Ltd., average diameter 13 μm] 3
0% by weight and DSP MB-600 as a polyphenylene sulfide resin composition (Dainippon Ink & Chemicals, Inc.)
Made of 70% by weight and then mixed with a twin screw extruder 2
Pelletization was performed in the range of 90 to 310 ° C.

The pellets were molded using an injection molding machine at a temperature of 290 to 310 ° C. to obtain a container in which the glass fibers were homogeneously dispersed. The appearance after immersion of this container in a hydrofluoric acid solution heated to 100 ° C for 1000 hours is rough compared to the state immediately after molding, and the bending strength retention rate under the same conditions is 20%, and when carbon fiber is used It was inferior to the acid resistance.

[0034]

The container comprising the carbon fiber and the polyarylene sulfide resin of the present invention is excellent in heat resistance and chemical resistance, and in particular, the required strength and appearance over a long period of time even when subjected to washing at high temperature. Thus, the present invention has the remarkable effect that it is not necessary to frequently transfer the object to be washed every cleaning solution. Therefore, it is useful as a container used at the time of hydrofluoric acid cleaning of a silicon wafer.

Claims (4)

[Claim of claim] 1. A container for cleaning acid-proof acid comprising carbon fiber and polyarylene sulfide resin. 2. The container according to claim 1, wherein the content of carbon fibers is 3 to 60% by weight. 3. The container according to claim 1, wherein the carbon fiber is a pitch-based bent carbon fiber. 4. The container for cleaning with acid-resistant acid according to any one of claims 1 to 3, wherein the cleaning container is a silicon wafer cleaning container. [0000]