JPH0297024A - Device for circulation and filtration of chemical for semiconductor wafer - Google Patents

Abstract

PURPOSE:To surly remove the dust in a chemical treatment vessel and to obtain the filter device with which the washing efficiency can be improved in an automatic washing device by a method wherein a first storage tank, in which the filtered chemical sent from the bottom of a chemical treatment vessel is stored, and a second storage tank on standby, storing the necessary quantity of constant-temperature chemical, are provided in the title filter device. CONSTITUTION:This filter device is provided with a chemical treatment vessel 30, with which a semiconductor wafer is surface-treated by dipping it therein, and a storage tank 40 in which the chemical taken out from the bottom part of the chemical treatment vessel 30 for removal of dust mixed in the chemical of the chemical vessel 30. In the chemical circulating filter device constituted in such a manner that the chemical in the storage tank 40 is filtered and returned to the chemical treatment vessel 30 again, the first storage tank 40, in which the filtered chemical comes out from the bottom part of the chemical treatment vessel 30 is stored, and a second storage tank 50 on standby, with the necessary quantity of chemical brought in constant temperature in advance, are provided. For example, after the chemical has been transferred to the second storage tank 50 from the first storage tank 40, the chemical is returned to the chemical treatment vessel 30, or the chemical is directly transferred to the chemical treatment vessel 30 while the chemical is being filtered.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a circulation filtration device for a chemical solution in a wet processing device in a semiconductor manufacturing process.

(Prior art) Conventionally, as a technology in this field, for example, Japanese Patent Application Laid-open No. 6
There were those described in No. 2-195130 and JP-A No. 62-281335.

Its configuration will be explained using figures.

FIG. 2 is a schematic configuration diagram of such a conventional chemical liquid circulation filtration device.

As shown in this figure, the chemical solution processing tank 1 was provided with an overflow tank 2, and the chemical solution that overflowed the overflow tank 2 was configured to be returned to the chemical solution processing tank 1 through a pump 3 and a filter 4.

However, in this chemical liquid circulation filtration method, the chemical liquid to be filtered is only the overflow from the overflow tank 2 provided on the outer periphery of the chemical liquid processing tank 1, and the chemical liquid in the stagnation part generated in the chemical liquid processing tank 1 is circulated and filtered. I can't. In other words, dust cannot be removed reliably. Therefore, all of the chemical liquid in the tank is once taken out from the bottom of the chemical liquid processing tank 1 and collected in a recovery tank, and the purified (filtered) chemical liquid is returned to the chemical liquid processing tank 1 again.

This IF passing method will be explained in detail using FIGS. 3 and 4.

In FIG. 3, a chemical solution (here, an etching solution) supplied to a recovery tank 5 is circulated and filtered through a pump 6, a filter 7, and a valve 8. Next, this chemical solution is applied to valve 9,
It is supplied to the chemical treatment tank 1 through the pump 6, filter 7, and valve 10, and in the chemical treatment tank 1, the pump 11 and the filter 1 are supplied.
2. It is circulated and filtered through the valve 13 and becomes ready for chemical treatment. After the chemical liquid treatment is completed, the chemical liquid is returned to the recovery tank 5 through the valve 14, pump 11, filter 12, and valve 15, and is circulated and filtered within the recovery tank 5, in preparation for the next chemical liquid treatment.

Further, in the chemical circulation filtration system shown in FIG. 4, by providing a valve 27 to reduce dust in the chemical, the chemical in the chemical treatment tank 22 flows into the filter 24 through the circulation vibrator 26, and is purified through a filter 24,
After all the chemical liquid in the chemical liquid processing tank 22 is stored in the storage tank 28, it is configured to be returned to the chemical liquid processing tank 22 again by the pump 25. In this way, the chemical liquid in the chemical liquid processing tank 22 is circulated all at once. The filter is configured to reduce dust in the chemical solution. In addition, here, 21
23 is a chemical liquid tank, 23 is a chemical liquid supply valve, and 29a and 29b are waste liquid valves.

(Problems to be Solved by the Invention) However, in the above-described all-chemical filtration method, the chemical remains in the piping etc. during transfer to the collection tank and retransfer to the chemical tank, resulting in a decrease in the chemical liquid capacity. Also, since this chemical solution is generally controlled at a constant temperature, it takes a certain amount of time for it to be ready for use when it is transferred back to the chemical solution tank, so it is recommended to use the chemical solution treatment tank continuously. It is impossible. Particularly, when processing is carried out in a fixed cycle, such as in an automatic cleaning device, the above-mentioned problems are clearly reflected.

SUMMARY OF THE INVENTION An object of the present invention is to provide a chemical circulation filtration device for semiconductor wafers that can eliminate the above-mentioned problems, reliably remove dust in a chemical processing tank, and improve work efficiency in an automatic cleaning device. .

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a chemical treatment tank in which a semiconductor wafer is immersed to perform surface treatment on the semiconductor wafer, and a chemical solution in the chemical treatment tank. A storage tank that takes out and stores a chemical solution from the bottom of the chemical processing tank in order to remove mixed dust; and a chemical circulation filtration device that is configured to filter the chemical solution from the storage tank and return it to the chemical processing tank. A first storage tank for storing the chemical liquid filtered from the bottom of the chemical liquid processing tank, and a second storage tank for holding a required amount of the chemical liquid at a constant temperature in advance are provided.

(Function) According to the present invention, as described above, the chemical liquid is stored in the first storage tank from the bottom of the chemical liquid processing tank through the pump and the filter, and a certain amount is weighed in advance into the empty chemical liquid processing tank, A second storage tank is also provided for supplying a chemical solution kept at a predetermined temperature. Then, the chemical liquid is transferred from the first storage tank to the second storage tank, and is weighed and kept at a constant temperature in preparation for the next liquid supply.

In addition, if there is a comparatively long margin in the processing cycle, the first storage tank may be directly filtered and transferred to the second storage tank without storing it in the second storage tank to maintain a constant weight and constant temperature. After that, the liquid can be supplied to the chemical treatment tank.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of a chemical circulation filtration apparatus for semiconductor wafers showing an embodiment of the present invention.

As shown in this figure, normally, the chemical liquid overflowing from the chemical liquid processing tank 30 is sent from an overflow part 31 through a circulation pipe 32 to a filter 34 by a pump 33, and after removing dust in the chemical liquid, it passes through a valve 35. Then, it is returned to the chemical treatment tank 30 again. In this case, valve 36. in the circulation pipe.
37.38.39 are closed.

Next, after a certain amount of processing and a certain amount of time have passed through the above circulation path, the valves 36 and 37 are opened and the valve 35 is closed, so that the chemical liquid in the chemical liquid processing tank 30 is transferred to the valve 36, the pump 33, the filter 34, and the valve 35. 37 and is transferred to the first storage tank 40. Here, the valve 38 and the drain valve 39 remain closed.

Next, the empty chemical treatment tank 30 is washed with pure water. At this time, the valve 36 is closed, the drain valve 39 is opened, the wash water is discharged, and the drain valve 39 is closed after washing. Here, valve 35.
38 remains closed.

Next, when the chemical liquid processing tank 30 becomes empty, the chemical liquid is supplied from the second storage tank 50 to the chemical liquid processing tank 30.

In this second storage tank 50, the amount of chemical liquid required to be supplied to the chemical liquid processing tank 30 is measured and stored using a weighing bag 254, for example, a level detector. Furthermore, the chemical solution is configured to be controlled to a predetermined temperature by a constant temperature control device 55.

The chemical liquid in the second storage tank 50 is stored at a valve 5 provided at the bottom.
1 is opened, the chemical solution is supplied to the chemical treatment tank 30 through the supply pipe 52. This method of supply is naturally carried out by a head, but a pressure pump may also be used.

Next, when the second storage tank 50 is empty, the first storage tank 40 opens the valve 41, passes through the pump 42 and transfer pipe 43, opens the switching valve 44, and passes through the transfer pipe 45. Then, the chemical solution is sent to the second storage tank 50. Note that a filtration filter may be provided after the pump 42.

In this way, the chemical liquid sent to the second storage tank 50 is weighed by the weighing device 54, and if the amount is less than the amount required to be supplied to the chemical liquid processing tank 30, the chemical liquid is supplied by the amount of the chemical liquid that is insufficient. It is supplied (supplied) from the valve 53. The chemical solution supplied to the second storage tank 50 is controlled to a predetermined temperature by the constant temperature control bag W55, and the chemical solution processing tank 3
Prepare for supply to 0.

In addition, when used in an apparatus or process that has a comparatively large processing amount and processing cycle, it is possible to filter the chemical solution from the chemical processing tank 30 and directly transfer it to the second storage tank 40 without sending it to the first storage tank 40. It can be transferred to tank 50. In this case, the second storage tank 50 is naturally empty. This transfer opens the valve 36 of the chemical treatment tank 30, passes through the pump 33, filter 34, valve 38, and transfer pipe 45, and is transferred to the second storage tank 50.

The transferred chemical liquid in the second storage tank 50 is managed by the same means as described above, and then supplied to the chemical liquid processing tank 30,
It is also possible to have processing wafers input while being circulated and filtered.

By installing such equipment and pipelines, manual work can be eliminated and labor savings, automation, and safety can be promoted.

Note that the present invention is not limited to the above embodiments,
Various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

(Effects of the Invention) As described in detail above, according to the present invention, there is a first storage tank that stores the chemical liquid filtered from the bottom of the chemical liquid processing tank, and a second storage tank that holds the necessary amount at a constant temperature in advance. Since a storage tank is provided, the temperature of the chemical solution can be controlled, and the chemical processing tank can be used in a short period of time.
It is possible to reliably remove dust from the chemical solution and greatly improve work efficiency.

Further, it is possible to compensate for the decrease in the amount of the chemical solution due to the chemical solution remaining in the piping etc. by filtration and transfer.

That is, immediately after the chemical liquid is poured from the chemical liquid processing tank to the first storage tank for filtration, the chemical liquid that has been filtered and whose quantity and temperature are controlled can be supplied from the second storage tank. , it is possible to speed up the start-up of the treatment after filtration.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a chemical circulation filtration device for semiconductor wafers showing an embodiment of the present invention, FIG. 2 is a block diagram of a conventional chemical circulation filtration device for semiconductor wafers, and FIG. 3 is a block diagram of another conventional semiconductor wafer chemical circulation filtration device. FIG. 4 is a block diagram of yet another conventional chemical circulation filtration device for semiconductor wafers. 30... Chemical solution processing tank, 31... Overflow part,
32...Circulation pipe, 33.42...Pump, 34
...Filter, 35°36, 37.3B, 39.4
1.44.51... Valve, 40... First storage tank, 45... Transfer pipe, 50... Second storage tank, 52... Supply pipe, 53... Chemical solution supply valve. Patent applicant Oki Electric Industry Co., Ltd.

Claims (4)

[Claims] (1) A chemical processing tank in which semiconductor wafers are immersed to perform surface treatment on the semiconductor wafers, and a chemical solution taken out from the bottom of the chemical processing tank and stored in order to remove dust mixed into the chemical solution in the chemical processing tank. and a chemical liquid circulation filtration device configured to filter the chemical liquid from the storage tank and return it to the chemical liquid processing tank, the first storage tank storing the chemical liquid filtered from the bottom of the chemical liquid processing tank. 1. A chemical solution circulation filtration device for semiconductor wafers, comprising: a second storage tank in which a necessary amount of the chemical solution is kept at a constant temperature in advance and is on standby. (2) The chemical liquid circulation filtration device for semiconductor wafers according to claim 1, wherein the chemical liquid is transferred from the first storage tank to the second storage tank and then returned to the chemical liquid processing tank. (3) The chemical liquid circulation filtration device for semiconductor wafers according to claim 1, wherein the chemical liquid is directly transferred to the second storage tank while being filtered from the bottom of the chemical liquid processing tank. (4) Claims 1, 2, or 3, characterized in that a decrease in the chemical solution caused by the chemical solution remaining in the piping or the like due to filtration or transfer is compensated for by replenishing the second storage tank with the chemical solution. A chemical liquid circulation filtration device for semiconductor wafers as described in 2.