JPH0831787A - Cleaning container - Google Patents

Abstract

PURPOSE:To eliminate unevenness in cleaning and improve efficiency, along with small pollution in cleaning solution, by using a container or surrounding walls with its space and height enough to carry in or out a workpiece, and straightening the flow of the cleaning solution. CONSTITUTION:A surrounding wall 13 for surrounding a workpiece 14 to be cleaned has its space and height enough to carry in and out the workpiece 14. The surrounding wall 13 is fixed to a bottom of a cleaning container 11. A porous supporting stage 15 with a given number of narrow holes is fixed at a position for the workpiece 14 to be sunk enough in a cleaning solution 17. The cleaning solution 17 is fed from a lower inlet opening 12 of the cleaning container 11 and discharged from a discharge opening 16 at a bottom of cleaning container under the supporting stage 15. In addition, a covering porous plate 20 for covering the upper part of the inlet opening 12 may be provided to straiten the flow of the cleaning solution or a porous plate 20' in parallel with the supporting stage 15 may be put at a distance of several centimeters downward from the supporting stage 15 in the surrounding wall 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning tank for cleaning a wafer or the like when manufacturing a semiconductor device.

[0002]

2. Description of the Related Art Generally, an overflow tank is used as a cleaning tank used for cleaning wafers and the like in the manufacture of semiconductor devices. As shown in FIG. 4, a cleaning solution injected from a cleaning solution inlet 2 provided at the bottom of the cleaning tank 1 is used. , The washing object 4 installed on the holding shelf 3
Inside or in the vicinity of the cleaning object 4, and flows upward, overflows from the free surface of the cleaning tank 1 into the groove 5 of the overflow tank provided on the outer periphery of the upper end of the cleaning tank 1, and is discharged from the discharge port 6 to the outside of the tank. It The cleaning object 4 is generally a plurality of wafers arranged in a cassette made of synthetic resin, and the upper part of the cassette is locked and transferred by a lifting tool of an automatic transfer device, and the cleaning liquid in the cleaning tank 1 is immediately above the cleaning tank 1. Immersed in. Further, the contaminated cleaning liquid discharged from the discharge port 6 is passed through the filter to be cleaned and then circulated and supplied again to the cleaning tank 1.

In the above-mentioned conventional technique, the cleaning liquid flowing from the bottom of the cleaning tank spreads and rises in the cleaning tank, but the flow velocity becomes slower than that of the cleaning liquid which has a large resistance when passing through the cleaning object and rises outside the cleaning object. , It is difficult to obtain a sufficient cleaning effect, and a part of the cleaning liquid that cannot overflow overflows along the inner wall of the cleaning tank to cause reflux, so that a part of the fine particles released from the cleaning product will remain. When the cleaning is repeated one after another, the cleaning liquid gradually becomes contaminated and the cleaning effect deteriorates. In order to solve these problems, the inventor has fixed a cylindrical enclosure having a gap and height enough to carry in and out the wash item to the bottom of the washing tank as shown in FIG. Install a support rack for the cleaning product with the required number of pores in the middle position where the water is sufficiently immersed, and use the discharge port that sucks and discharges the cleaning liquid injected from the injection port on the outside of the wall below the cleaning tank. Proposed a cleaning tank installed at the bottom of the cleaning tank (Japanese Patent Application No. 5-
260506).

[0004]

With the above proposal, the problems of the overflow type cleaning tank have been greatly improved.
Further, in order to improve the cleaning efficiency of the cleaning tank, it is necessary to further clean the cleaning liquid in the cleaning tank, and it is necessary to uniformly flow the cleaning liquid to the cleaning object.

It is an object of the present invention to obtain a cleaning tank which straightens the flow of cleaning liquid and can perform uniform cleaning operation without unevenness.

[0006]

[Means for Solving the Problems] The above object is to provide a cylindrical surrounding wall having a clearance and a height for carrying in and out a wash item.
A perforated plate, which surrounds the periphery of the cleaning object and is fixed to the bottom of the cleaning tank, is provided with a predetermined number of predetermined pores at a position where the cleaning object is sufficiently immersed in the cleaning liquid in the surrounding wall, supports the cleaning object. A discharge port provided as a shelf for sucking and discharging the cleaning liquid injected from the injection port provided at the lower part of the cleaning tank outside the surrounding wall is provided in the cleaning tank provided at the bottom of the cleaning tank below the support shelf with a rectifying means for the cleaning liquid. It is achieved by providing it in the cleaning tank or in the surrounding wall.

Further, the cleaning liquid rectifying means in the cleaning tank is
By using a perforated plate that covers the inside of the upper cleaning tank of the inlet on the outside of the surrounding wall, or the cleaning liquid rectifying means inside the surrounding wall is a perforated plate provided at a lower portion of the support shelf inside the surrounding wall. Alternatively, or by forming the cross section of the surrounding wall below the support shelf into a funnel-shaped downward section.

[0008]

In the cleaning tank according to the present invention, the cleaning object is installed on the support shelf provided in the middle of the cylindrical enclosure fixed to the bottom of the cleaning tank, and the cleaning solution injected from the injection port at the bottom of the cleaning tank on the outside of the enclosure is used. The cleaning liquid is poured from the upper part of the enclosure wall to clean it, and the contaminated cleaning liquid is discharged to the outside of the cleaning tank from the discharge port at the bottom of the cleaning tank below the support shelf. The cleaning solution is injected from a few injection ports provided in the lower part of the cleaning tank and diffuses into the tank, but the flow rate of the cleaning solution rising in the tank becomes nonuniform and varies depending on the location.
This non-uniform flow rate is almost averaged by passing through the perforated plate provided at the upper part of the injection port, and the rectified cleaning liquid can be poured into the cleaning object. Further, the contaminated cleaning liquid that passes through the support rack after cleaning has a flow velocity distribution in which the flow velocity is large around the discharge port and decreases as it approaches the inner surface of the enclosure wall. By providing the perforated plate below, the flow rate of the contaminated cleaning liquid is made substantially uniform. Furthermore, by forming the wall below the support shelf into a funnel shape, the contaminated cleaning liquid near the wall with a low flow velocity can be quickly transported to the discharge port, and the particles in the contaminated cleaning liquid are stagnant and adhere to the wall. Can be prevented.

[0009]

Embodiments of the present invention will now be described with reference to the drawings. 1 is a sectional view showing a first embodiment of a cleaning tank according to the present invention, FIG. 2 is a sectional view showing a second embodiment according to the present invention, and FIG.
FIG. 7 is a sectional view showing a third embodiment according to the present invention.

First Embodiment Referring to FIG. 1 showing a first embodiment of the present invention, an enclosure wall 13 having a gap and a height for carrying in and out a wash item 14 is provided.
A perforated plate provided with a predetermined number of predetermined pores is provided at a position surrounding the cleaning object 14 and fixed to the bottom of the cleaning tank 11, and the cleaning object is sufficiently immersed in the cleaning liquid 17 in the surrounding wall 13. The cleaning liquid 1 is provided as a support shelf 15 for the cleaning liquid 14 and is injected from the injection port 12 in the lower part of the cleaning tank 11 outside the surrounding wall 13.
7 is a discharge port 16 provided at the bottom of the cleaning tank below the support shelf 15.
In the cleaning tank discharged from the above, the perforated plate 20 covering the inside of the upper cleaning tank of the injection port 12 serves as a rectifying means for the cleaning liquid.
Is provided.

The injection port 12 for the cleaning liquid is provided at or near the bottom surface of the cleaning tank 11, but the number thereof is limited due to the structure, and a large number cannot be provided. Therefore,
The cleaning liquid injected from the injection port 12 diffuses in the cleaning tank 11, but does not diffuse uniformly, and the flow rate of the cleaning liquid rising in the cleaning tank 11 constantly changes depending on the place and becomes nonuniform. However, by providing the perforated plate 20 in the cleaning tank above the inlet as in the present embodiment, the cleaning liquid passing through the pores of the perforated plate 20 is rectified and the inside of the cleaning tank 11 is flowed at a substantially uniform flow rate. And the cleaning material 14 can be uniformly washed at a uniform flow rate by flowing from the upper edge of the surrounding wall 13 into the surrounding wall, so that the cleaning time can be shortened and the cleaning efficiency can be improved.

Second Embodiment In the second embodiment of the present invention, as shown in FIG. 2, a perforated plate 20 ′ is formed under the support shelf 15 in the surrounding wall 13 at a distance of several cm from the support shelf 15. It is provided in parallel. The cleaning liquid that has released pollutant particles by passing through the gaps and the periphery of the cleaning object 14 is
Although it is discharged from the support shelf 15 through the outlet 16 to the outside of the cleaning tank 11, the discharge port 16 is generally smaller than the cross section of the surrounding wall,
The flow velocity of the contaminated cleaning liquid in the surrounding wall below the support shelf 15 becomes large at the center of the discharge port 16 and becomes smaller as it spreads to the periphery. Therefore, the contaminated particles tend to stagnate in the vicinity of the surrounding wall, and the contaminated particles are mixed on the support shelf 15 due to long-term use, and the cleanliness of the cleaning liquid decreases. In this embodiment, since the perforated plate 20 'is provided below the support shelf 15, the contaminated cleaning liquid has a good rectifying property and the contaminated fine particles can be promptly removed from the cleaning tank 11.

Third Embodiment In a third embodiment of the present invention shown in FIG. 3, a funnel-shaped enclosure wall 18 is formed by forming the enclosure wall below the support shelf 15 so that the cross-sectional shape becomes smaller as it goes downward. As described in the second embodiment, the contaminated cleaning liquid tends to stay in the inside wall of the support shelf 15, and when repeated cleaning is performed for a long period of time, contaminated fine particles adhere to the inner surface of the peripheral wall, and The cleaning liquid will be contaminated by the contaminated fine particles. In this embodiment, since the wall under the support shelf is formed in a funnel shape, the flow of the contaminated cleaning liquid along the funnel-shaped wall is made smooth, and the contaminated fine particles accumulated on the surface of the wall due to the stagnation of the contaminated cleaning liquid are quickly discharged. Therefore, it is possible to obtain a cleaning tank with reduced cleaning liquid contamination and good cleaning efficiency.

The above-mentioned respective embodiments can be carried out individually or in any combination to obtain a cleaning tank with further excellent cleaning efficiency.

[0015]

As described above, in the cleaning tank according to the present invention, a cylindrical surrounding wall having a gap and a height for carrying in and out the cleaning material is fixed to the bottom of the cleaning tank so as to surround the cleaning material. , A perforated plate provided with a required number of predetermined pores was provided as a support rack for the cleaning object at a position where the cleaning object inside the enclosure was sufficiently immersed in the cleaning liquid, and was provided in the lower part of the cleaning tank outside the enclosure wall. The outlet for sucking and discharging the cleaning liquid injected from the inlet is
In the cleaning tank provided at the bottom of the cleaning tank below the support shelf,
The cleaning liquid is rectified by providing the cleaning liquid rectifying means in the cleaning tank or in the surrounding wall, or the surrounding wall under the support shelf is formed into a funnel shape to facilitate the discharge of the contaminated cleaning liquid and to be used for a long time. Contrary to this, the cleaning liquid can be prevented from being contaminated and the cleaning efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of a cleaning tank according to the present invention.

FIG. 2 is a sectional view showing a second embodiment of the cleaning tank according to the present invention.

FIG. 3 is a sectional view showing a third embodiment of the cleaning tank according to the present invention.

FIG. 4 is a cross-sectional view showing a conventional cleaning tank.

FIG. 5 is a sectional view showing a conventional improved cleaning tank.

[Explanation of symbols]

 11 Washing Tank 12 Injection Port 13 Enclosure 14 Washed Material 15 Support Shelf 16 Discharge Port 17 Washing Liquid 18 Funnel-shaped Enclosure 20, 20 'Perforated Plate

Claims (4)

[Claims] 1. A cylindrical surrounding wall having a gap and a height for carrying in and out the cleaning material is fixed to the bottom of a cleaning tank so as to surround the cleaning material so that the cleaning material in the surrounding wall is sufficiently a cleaning liquid. A perforated plate provided with a required number of predetermined pores is provided as a support shelf for the cleaning object at a position to be immersed in the substrate, and the cleaning solution injected from the inlet provided in the lower part of the cleaning tank outside the surrounding wall is sucked and discharged. A washing tank having an outlet provided at the bottom of the washing tank below the support shelf, wherein the rectifying means for the washing liquid is provided in the washing tank or in the surrounding wall. 2. The cleaning tank according to claim 1, wherein the cleaning liquid rectifying means in the cleaning tank is a perforated plate which covers the inside of the upper cleaning tank of the injection port outside the surrounding wall. 3. The cleaning tank according to claim 1, wherein the cleaning liquid rectifying means in the surrounding wall is a perforated plate provided at a lower portion of a support shelf in the surrounding wall with a space therebetween. 4. The cleaning liquid rectifying means in the enclosure wall is formed so that the transverse section of the enclosure wall below the support shelf is formed in a funnel shape so as to be smaller downward. Cleaning tank.