JP2000084314A - Filter for liquid chemical - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the drying of a filter part and to prevent the lowering of flow rate through a filter for liquid chemical by providing a pipe line for discharging air, which extends downward from vicinity of the upper end and leads to the outside of the filter, in the filter part communicated with a flow-out port of the filter for liquid chemical. SOLUTION: In a cleaning vessel for cleaning a material to be cleaned such as a substrate with the liquid chemical 1, discharge pipes are provided on both sides of the lower side of the inside of a vessel body and are connected to a pump and a filter 20A through a pipe line. In the filter 20A, a pipe line 28 for discharging air is provided in the filter part 25 and is arranged on the same axis as the filter part 25. The upper end part of the pipe line 28 for discharging air is positioned near a lid body 25a of the filter part 25 and the lower end part extends to the outside of a housing 21 of the filter 20A from the bottom part (near the connected position to a flow-out port 23) of the filter part 25. As a result, the air A is prevented from flowing out with the liquid chemical 1, the sticking of particles on the surface of the material to be cleaned is prevented and etching defect is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical liquid filter for cleaning an object to be cleaned such as a wafer or a substrate with a chemical liquid and circulating the chemical liquid.

[0002]

2. Description of the Related Art Conventionally, when cleaning an object to be cleaned such as a wafer or a substrate, the cleaning object is accommodated in a cleaning tank main body, the cleaning tank main body is filled with a chemical solution, and a chemical solution is pumped. 2. Description of the Related Art A cleaning method of spraying an object to be cleaned is known. And in this cleaning method, the chemical used for cleaning is
Circulating through the filter. That is, the chemical solution once used for cleaning is discharged out of the cleaning tank, and is sent again into the cleaning tank main body through the filter.

FIG. 3 is a sectional view showing an example of a conventional filter. The housing 21 of the filter 20 is formed in a substantially hollow cylindrical shape, and includes an inflow port (primary side) 22 communicating with the inside of the housing 21. In addition, a ventilation port 24 is formed at the upper end. Further, a substantially cylindrical filtering section 25 is provided in the housing 21.

The filtering section 25 has a lid 25a on the top side and a filter layer 25b (hatched portion in the figure) on the side. The inside of the filtration unit 25 and the outlet (secondary side) 2
3 are in communication. In addition, the drain ports 26 and 27 provided in communication with the vicinity of the inflow port 22 and the outflow port 23, respectively.
Is a part that is closed when in use, and is used, for example, when replacing the filtration unit 25.

[0005] The chemical solution 1 used for cleaning is a filter 2
When the liquid enters the inside from the inflow port 22 of No. 0, it passes through the filter layer 25b and enters the filtration unit 25. At this time, the chemical 1 is the filter layer 2
Filtered by 5b. The air that has entered together with the liquid medicine 1 from the inflow port 22 is discharged to the outside through the airflow opening 24. The chemical solution 1 that has entered the filtration unit 25 exits from the outlet 23, and is sent again into the washing tank through a predetermined pipeline.

[0006]

However, in the above-described conventional filter 20, when the air A enters the filtration unit 25 together with the chemical 1, the upper end (in the upper part of the chemical 1) in the filtration unit 25 as shown in FIG. Air A accumulates in the air A
Flows out together with the liquid medicine 1 from the outlet 23. Due to the presence of the air A, there are problems such as particles adhering to the surface of the object to be cleaned and etching defects.

Furthermore, since the air A continues to accumulate in the filtration section 25, the filter layer 25b is dried, and the flow rate of filtration is reduced, and the life of the filter 20 is shortened. Therefore, a problem to be solved by the present invention is to prevent air from accumulating in the filtration section of the filter.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a chemical liquid filter for discharging a chemical liquid entering from an inlet through an outlet through a filter, wherein the filter inside the filter communicates with the outlet. An air discharge pipe extending from the vicinity of the upper end to the outside of the chemical liquid filter is provided.

[0009]

According to the present invention, the chemical liquid entered from the inlet of the chemical liquid filter is purified by passing through the filtration section, and is discharged from the outlet. In addition, air that enters from the inflow port together with the chemical solution and enters the filtration unit is collected at the upper end portion in the filtration unit, but is always discharged to the outside of the chemical solution filter through the air discharge pipe. Therefore, air does not accumulate in the filtration unit.

[0010]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a front sectional view showing a cleaning tank 10 to which a filter (for a chemical solution) 20A according to the present invention is applied. The cleaning tank 10 is of a turbulent flow type chemical circulation type. In the cleaning tank 10, a discharge pipe 12 for discharging the chemical liquid (cleaning liquid) 1 is provided on both lower sides inside the tank main body 11. A filter 20A according to one embodiment of the present invention is connected.

The object 2 to be cleaned is accommodated in the tank body 11 and the chemical 1 is ejected from the discharge pipe 12 by the pump 14 to wash the object 2 to be cleaned. The object 2 to be cleaned is a silicon wafer, a glass substrate of a liquid crystal display, or the like, and is supported by a receiving table (not shown) installed on the inner bottom surface of the tank body 11. The chemical solution 1 overflowing from the top surface side opening surface of the tank body 11 is stored in the storage tank 1 provided on the outer periphery of the tank body 11.
6 and again by the pump 14 to the filter 20
A is supplied into the tank main body 11 through A.

FIG. 2 is a cross-sectional view showing a filter 20A which is an embodiment of a filter for a chemical solution according to the present invention. In the filter 20A of FIG. 2, the same parts as those of the filter 20 shown in the conventional example are denoted by the same reference numerals, and overlapping description will be omitted. Filter 20A in the present embodiment
Is compared with the filter 20 in the conventional example,
A different point is that a straw-shaped air discharge pipe 28 is provided therein.

The air discharge pipe 28 is disposed substantially coaxially with the filtration section 25. The upper end of the air discharge pipe 28 is located near the lid 25 a in the filtration unit 25.
The lower end extends from the bottom of the filtration unit 25 (near the connection position with the outlet 23) to the outside of the housing 21 of the filter 20A.

Thus, the air A collected at the upper end in the filtration section 25 is constantly discharged to the outside through the air discharge pipe 28 due to the pressure difference from the chemical solution 1. Therefore, the air A does not accumulate in the filtration unit 25. Therefore, the filter layer 25b does not dry out, and a decrease in the flow rate of the filter 20A can be prevented. In addition, since the air A does not flow out together with the chemical solution 1, particles can be prevented from adhering to the surface of the object to be cleaned, and defective etching can be eliminated.

[0015]

According to the present invention, the air accumulated in the filtration section is discharged to the outside through the air discharge pipe, so that the air does not accumulate in the filtration section. Therefore, drying of the filtration unit is eliminated, and a decrease in the flow rate of the chemical liquid filter can be prevented. In addition, since air is not mixed in the chemical solution that has passed through the chemical solution filter, it is possible to prevent particles from adhering to the surface of the object to be cleaned and to eliminate poor etching.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing a cleaning tank to which a chemical liquid filter according to the present invention is applied.

FIG. 2 is a cross-sectional view showing one embodiment of a filter for a chemical solution according to the present invention.

FIG. 3 is a cross-sectional view illustrating an example of a conventional filter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Chemical solution 20A Filter for chemical solutions 21 Housing 22 Inflow port 23 Outflow port 24 Ventilation port 25 Filtration part 25a Lid 25b Filter layer 26, 27 Drainage port 28 Air discharge pipeline A Air

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01D 35/02 Z

Claims (1)

[Claims] 1. A filter for a chemical solution which discharges a chemical solution entering from an inlet through an outlet through an outlet, wherein air extending downward from near an upper end of the filter communicating with the outlet and communicating with the outside of the filter for chemical solution. A chemical liquid filter having a discharge pipe.