JPS63272040A - Circulating filtering and washing equipment - Google Patents

Abstract

PURPOSE:To obtain an equipment which facilitates maintaining the concentration of an agent and the concentrations of organic substances, metal impurities and fine particles in the agent and pure water for a long time and washing wafers uniformly by a method wherein a washing bath, an overflow apparatus, a pump, an ultraviolet pasteurizer, a gas-liquid separator, a filter, densitometers, an automatic supply means and so forth are provided. CONSTITUTION:At least a washing bath 22, an overflow apparatus 13 which precipitates and filters impurities in washing solution, a pump 11 which pumps up the washing solution from the washing bath 22 and supplies to the overflow apparatus 13, an ultraviolet pasteurizer 28, a gas-liquid separator 29 and a filter 12 which are provided at the intermediate part of a pipe connecting the pump 11 to the overflow apparatus 13 and a means which supplies pure water and agent to the washing bath 22 to dilute or concentrate the washing solution automatically in accordance with the outputs of densitometers 30 and 30' are provided. Further, for instance, a stirrer 23 using nitrogen gas and a liquid level sensor 19 for stabilizing the liquid level are provided in the washing bath 22 and a liquid container 14 in which the agent is stored, a nozzle 16 which can be inserted into and drawn out of the container 14 by an air cylinder 15, a weighing bath 18 and a depressurizer 17 are provided in a chemicals feeder 33.

Description

[Detailed Description of the Invention] [Summary] This is a circulating filtration cleaning device that removes organic substances, metal impurities, and fine particles contained in chemicals and pure water used for wafer cleaning using a filter, ultraviolet sterilization device, etc. By automatically adjusting the chemical concentration, impurities in the chemical/pure water and the chemical concentration can be maintained at constant values, and uniform wafer cleaning can be performed.

[Industrial application field]

The present invention relates to a cleaning apparatus used for cleaning wafers and the like in the manufacturing process of semiconductor devices.

[Conventional technology]

As shown in FIG. 3, conventional wafer cleaning equipment uses chemicals (such as sulfuric acid) in a processing tank 2 as polyethylene.

After wafers 5 are placed in a wafer storage box 4 called a basket from a container 3 made of glass or the like, the wafers are cleaned with chemicals and pure water. Fine particles, metal impurities, etc. increase each time the wafers 5 are cleaned, so after a certain number of wafers 5 have been cleaned, the chemicals and pure water in the processing tank 2 are discarded and replaced with new chemicals and pure water. . Note that exhaust gas and water are treated by an exhaust gas treatment device shown in FIG. 4 and a wastewater treatment device shown in FIG. 5.

[Problem that the invention seeks to solve]

In the conventional wafer cleaning equipment described above, ■ large amounts of chemicals and pure water are used; @Wafers cannot be cleaned uniformly because the levels of fine particles, metal impurities, etc. in the new chemicals/deionized water and the chemicals/deionized water before disposal are different. Since the amount of O chemicals and pure water used is large, the processing capacity of the exhaust gas treatment device shown in FIG. 4 and the wastewater treatment device shown in FIG. 5 must be increased. (2) When cleaning wafers by heating chemicals and pure water using the heater 6, the concentration of the chemicals changes depending on the heating time, and the cleaning ability changes. There were other problems.

The present invention was created in view of these points.
Concentration of chemicals and organic matter in chemicals and pure water.

It is an object of the present invention to provide a circulating filtration and cleaning device that can maintain the concentration of metal impurities and particulates at a constant value over a long period of time and perform uniform wafer cleaning.

[Means for Solving the Problems] Therefore, in the present invention, as illustrated in FIG. a pump II that pumps up and sends it to the overflow device 13;
An ultraviolet sterilizer 28 is provided in the middle of the pipe connecting the pump 11 and the overflow device 13. It is equipped with at least a gas/liquid separator 29, a filter 12, and means for automatically performing dilution and concentration by replenishing pure water and chemicals into the cleaning tank 22 using concentration meters 30 and 30' that detect the concentration of chemicals in the cleaning liquid. It is characterized by what it did.

[For production]

Resist in the cleaning solution by ultraviolet sterilizer 2B.

By decomposing organic substances such as bacteria into gas and removing them, clogging of the filter 12 is prevented.
The cleaning liquid can be circulated and used by removing metal impurities and fine particles in the cleaning liquid with the overflow device 13 and the overflow device 13.
When the chemical concentration in the cleaning solution increases due to the heating heater 32, or when the chemical concentration decreases due to moisture brought in from the wafer, etc., the concentration meters 30 and 30' automatically replenish pure water and chemicals for dilution and concentration. By maintaining the concentration at a constant level, it is possible to maintain the cleaning ability at a constant level.

〔Example〕

FIG. 1 is a diagram showing an embodiment of the present invention.

As shown in FIG. 1, this embodiment includes a cleaning tank 22, a pump 11 that pumps cleaning liquid from the cleaning tank 22, an ultraviolet sterilizer 28 connected to the pump 11, a gas/liquid separator 29. It is configured to include a filter 12, an overflow device 13, a chemical supply device 33, and the like.

The cleaning tank 22 has a stirring device 22 that uses nitrogen gas.
3, a liquid level sensor 19 for keeping the liquid level constant, and a concentration meter 30 for detecting the drug concentration, and the overflow device 13 has a rectangular cylinder shape as shown in FIGS. ,
A large number of ■-shaped or U-shaped grooves are formed at the upper end of the cylindrical tank shown in d, and the cleaning liquid that overflows from the cleaning liquid flows in all directions and returns to the cleaning tank 22, where particles settle and enter the tank. It is meant to remain. Also, this overflow device 1
3 is provided with a heater 32 for heating the cleaning liquid and a concentration meter 30° for detecting the chemical concentration, as shown in FIG.
At the same time, the chemical concentration of the cleaning liquid is monitored, and when it exceeds a specified value, the pure water valve 31 is opened to replenish pure water until the specified concentration is reached, and when the concentration falls below the specified value, the valve 21 is opened. The system replenishes chemicals until they reach the specified concentration. Further, the chemical supply device 33 includes a liquid container 14 for storing chemicals, a nozzle 16 that is inserted into and removed from the container 14 by an air cylinder 15, a weighing tank 18 connected to the nozzle 16, and a medicine in the liquid container 14 in the weighing tank. It is equipped with a pressure reducer 17 etc. for inhaling.

In this embodiment configured as described above, pure water is poured into the cleaning tank 22 to a specified level, then the liquid container 14 is automatically placed into the container using the air cylinder 15, and the nozzle 16 is put into the container, and the pressure reducer 17 The chemical is inhaled into the container of the weighing tank 18, and when the weighing tank 18 reaches a certain level, the liquid level sensor 19 closes the valve 20, and at the same time opens the valve 21 to close the cleaning tank 2.
Supply to 2. This is stirred with a stirrer 23 using nitrogen gas to form a cleaning liquid, and then the valve 24 is opened and the pump 1
1 and the cleaning liquid is transferred to the ultraviolet sterilizer 28 and the gas/liquid separator 29. Filter 12. The wafers are cleaned while being circulated through the overflow device 13 and returned to the cleaning tank 22, but as a large number of wafers are cleaned, organic substances, metal impurities, fine particles, etc. increase in the cleaning liquid. Organic substances such as resist and bacteria in this are decomposed into gas by ozone or the like in an ultraviolet sterilizer 28 and removed through a gas/liquid separator 29. Further, metal impurities and fine particles are filtered by a filter 12 and further separated by an overflow device 13, and the cleaning liquid from which fine particles have been removed is returned to the cleaning tank 22. The particulates removed by the overflow device 13 are removed by opening the valve 26. Further, even when the overflow device 13 is not in use, the valve 25 can be opened to circulate the cleaning liquid.

Furthermore, when the cleaning liquid is heated by the heater 32 and used for a long time, the water evaporates and the concentration of the chemical increases. In such a case, the concentration meter 30, 30' detects this and opens the pure water valve 31 to adjust the concentration of the chemical. By replenishing pure water until the concentration is reached, the cleaning ability can be maintained at a constant level. Similarly, if the concentration of the chemical drops due to water being brought in from the wafer, etc., the concentration meters 30 and 30' will detect this, and the valve 21 will be opened to replenish the chemical until the specified concentration is reached, keeping the cleaning performance constant. be able to.

〔Effect of the invention〕

As described above, according to the present invention, organic matter, metal impurities, and fine particles in the cleaning liquid can be filtered.

It is removed using an ultraviolet sterilizer, etc., and the concentration of chemicals is diluted and
By concentrating and keeping the concentration constant, chemicals can be circulated and used without being disposed of, reducing the amount of cleaning fluid used, and improving and stabilizing the quality of cleaned products, increasing yield. Furthermore, automatic dilution and concentration are possible, reducing work hours and improving safety. In addition, it is not necessary to increase the capacity of waste water and exhaust gas treatment equipment, and effects such as improved pollution prevention ability can be achieved, which is extremely useful in practical terms.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an embodiment of the present invention, Fig. 2 is a diagram showing an overflow device used in an embodiment of the present invention, Fig. 3 is a diagram showing a conventional wafer cleaning device, and Fig. 4 is a diagram showing a conventional exhaust gas FIG. 5 is a diagram showing a conventional wastewater treatment device. In FIG. 1, 11 is a pump, 12 and 12' are filters, 13 is an overflow device, 14 is a liquid container, 15 is an air cylinder, and 16
is a nozzle, 17 is a pressure reducer, 18 is a weighing tank,
19 is a liquid level sensor, 20 , 21 , 24
~27 are valves, 22 are cleaning tanks, 23 are stirring devices, 28 are ultraviolet sterilizers, 29 are gas/liquid separators, 30 and 30° are concentration meters, 3
1 is a pure water valve, 32 is a heater, and 33 is a chemical supply bag/place.

Claims (1)

[Claims] 1. A cleaning tank (22), an overflow device (13) for separating impurities in the cleaning liquid by sedimentation and filtration, and the cleaning tank (22)
The cleaning liquid is pumped up from the overflow device (13
), an ultraviolet sterilizer (28) installed in the middle of the pipe connecting the pump (11) and the overflow device (13), and a gas/liquid separator (29).
, a filter (12), and means for automatically replenishing pure water and chemicals to the cleaning tank (22) and diluting and concentrating them using concentration meters (30, 30') that detect the chemical concentration of the cleaning liquid. A circulating filtration cleaning device that is characterized by: