JPH0562959A - Cleaning tank - Google Patents

Abstract

PURPOSE:To enhance a cleaning tank in mechanical strength, to make its surface smooth, and to lessen substance dissolved from the tank into ultra-pure water by a method wherein the cleaning tank is formed of aromatic polyether ketone resin. CONSTITUTION:Aromatic polyether ketone resin is formed into sheets through an injection molding method or an extrusion molding method, and the sheet concerned is molded into a cleaning tank through a thermoforming method or the like. No limitation is imposed on the cleaning tank in shape, but the cleaning tank is required to be large enough to house a wafer carrier or more or a liquid crystal glass substrate carrier or more. The cleaning tank is high in surface smoothness, small in substance dissolved into ultra-pure water, and excellent in characteristics as a cleaning tank.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning tank used for cleaning thin plate articles such as semiconductor wafers, glass for photomasks or glass substrates for liquid crystals.

[0002]

2. Description of the Related Art In thin plate-shaped articles such as semiconductor wafers and glass for photomasks, stains on the surface thereof have a great influence on the yield and performance of the products. As dirt, fine particles,
There are ionic substances and organic substances. In order to remove this dirt, for example, the cleaning of the semiconductor wafer is performed as follows. First, about 25 wafers placed in a holding container for the purpose of improving cleanliness are washed in a washing tank containing various chemicals. Next, it is transferred to a running water cleaning tank and the chemical liquid adhering to the wafer and the holding container is washed off with ultrapure water. Further, the wafer is dried by a centrifugal dryer or the like. Conventionally, as the running water washing tank, those made of quartz glass and fluororesin are known. However, the cleaning tank made of quartz glass is problematic in that it is easily damaged, has many restrictions in production, and is expensive. For this reason, many fluororesin materials that are not easily damaged are also used. As the fluororesin, a tetrafluoroethylene resin (hereinafter referred to as PTFE) or a tetrafluoroethylene-perfluoroarvinyl ether copolymer resin (hereinafter referred to as PFA) is used. PTF
Since E cannot be molded by a general thermoforming method and is commercialized by a thermal compression method, and PFA can be molded by a general thermoforming method, cleaning tanks of various sizes have been commercialized. PTFE, PFA
In the case of a large-sized cleaning tank, the mechanical strength is low, so that the cleaning tank needs to be thick, which is a constraint on the product design. In addition, there is a problem in that a cleaning tank made of PTFE or PFA has a large amount of eluate in ultrapure water. Furthermore, PTF
Since the cleaning tank made of E has a rough surface, there is also a problem that fine particles tend to remain in the ultrapure water during cleaning with ultrapure water.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a cleaning tank which is excellent in mechanical strength, has a smooth surface, and has little eluate in ultrapure water.

[0004]

Means for Solving the Problems As a result of intensive studies for achieving the above-mentioned object, the present inventors have completed the present invention by molding a cleaning tank with an aromatic polyetherketone resin. It was. That is, the present invention is a cleaning tank formed by molding an aromatic polyether ketone resin. The aromatic polyether ketone resin used in the present invention is represented by the formula (I) (formula 1) or (II) as a typical example.
It is a thermoplastic crystalline resin having a repeating unit represented by (Chemical Formula 2).

[0005]

[Chemical 1]

[0006]

[Chemical 2] For example, a VIC manufactured by ICI, which has a structure of formula (I)
TREX (trademark) PEEK, and VICTREX (trademark) P manufactured by ICI as having the structure of formula (II).
There are EK etc.

The above-mentioned aromatic polyetherketone resin is molded into a cleaning tank by an injection molding method, a thermoforming method using a sheet produced by extrusion molding, or the like. The shape of the cleaning tank is not particularly limited, but it is necessary to have a size capable of holding and cleaning one or a plurality of wafer carriers and liquid crystal glass substrate carriers inside.

Hereinafter, the present invention will be described in more detail with reference to examples. The surface roughness was measured using a surface roughness measuring device Surftest 402 (trade name) manufactured by Mitutoyo Corporation. Furthermore, total organic carbon (abbreviated as TOC) in ultrapure water
Was measured using a TOC engineering analyzer TOC automatic analyzer MODEL T0C-710 (trade name).

[0009]

Example 1 A PEEK sheet obtained by extrusion molding VICTREX (trademark) PEEK manufactured by ICI was molded into a cleaning tank by hot-press molding. The PEEK sheet used has a thickness of 550μ.
m, width 750 mm, and length 600 mm. Hot air pressure molding is TYPE PH, a pressure air molding machine manufactured by Fuse Vacuum Co., Ltd.
SL-1010-PWB, upper heater temperature 500
C., lower heater temperature 500.degree. C., heating time 70 seconds. The size of the obtained cleaning tank is 240 mm in length,
The width was 310 mm and the depth was 280 mm. When the surface roughness of the inner surface of the PEEK cleaning tank thus obtained was measured, it was Ra 0.85 μm and Rmax 4.8 μm. Next, after the inside of this cleaning tank was washed with ultrapure water, it was filled with ultrapure water and kept at 80 ° C. After 24 hours, ultrapure water was taken out and the amount of TOC eluted was measured and found to be 55 ppb.

Comparative Example A commercially available PTFE tank having a length of 160 mm, a width of 320 mm, and a depth of 270 mm was obtained, and the surface roughness of the tank and the TOC of the ultrapure water held in the tank were measured in the same manner as in Example 1. .. Surface roughness is Ra 3.7 μm, Rmax 27
μm, and TOC in ultrapure water was 180 ppb.

[0011]

The cleaning tank formed by molding the aromatic polyetherketone resin of the present invention has excellent surface smoothness and less elution into pure water, and has excellent characteristics as a cleaning tank.

Claims (1)

[Claims] 1. An ultrapure water cleaning tank for cleaning thin-plate articles such as semiconductor wafers and glass for photomasks, wherein the cleaning tank is formed by molding an aromatic polyetherketone resin.