KR19990069985A - Filter section with valves for removing bubbles - Google Patents

Abstract

The present invention relates to a filter unit of a semiconductor manufacturing equipment, comprising: a filter for filtering a chemical solution; a chemical solution inlet tube connected to a lower part of the filter; a chemical solution discharge tube connected to an upper part of the filter; And a first valve interposed in a predetermined region of the bubble discharge pipe, a second valve for controlling opening and closing of the first valve, and a pulse signal generator for generating an electrical signal for controlling opening and closing of the second valve.

Description

Filter section with valves for removing bubbles

The present invention relates to a device used to manufacture a semiconductor device, and more particularly, to a filter unit having a function of removing bubbles generated when filtering a chemical solution.

Various chemical solutions are used to manufacture semiconductor devices. Such chemical solution is filtered by a filter to prevent the surface of the semiconductor substrate from being contaminated by impurities. At this time, bubbles may occur in the filter, and these bubbles lower the filtration function of the filter. Therefore, bubbles present in the filter must be removed.

1 is a schematic view for explaining a filter unit according to the prior art.

Referring to FIG. 1, a conventional filter unit includes a filter F for filtering impurities in a chemical solution, a chemical solution injection tube I for injecting an unfiltered chemical solution C1 into the filter F, A chemical solution discharge pipe (O) for discharging the filtered chemical solution (C2) from the filter (F), a bubble discharge pipe (VL) communicating from a wall of the filter (F) near the chemical solution discharge pipe (O), and And a manual valve V interposed in a predetermined region of the bubble discharge pipe VL. Here, the chemical solution injection pipe (I) is connected to the lower portion of the filter (F), the chemical solution discharge pipe (O) is connected to the upper portion of the filter (F). At this time, the bubbles generated inside the filter F are collected by moving to the upper portion of the filter F. Therefore, the bubble discharge pipe VL for discharging the bubble B is installed in the upper part of the filter F, that is, around the chemical solution discharge pipe O. In addition, the bubbles collected on the upper portion of the filter F are discharged through the bubble discharge pipe VL when the manual valve V is opened by the operator.

As described above, in the conventional filter unit, bubbles formed in the filter F are discharged by the operator artificially operating the manual valve. Therefore, there is a problem in that it is difficult to remove bubbles efficiently as well as it is troublesome in manufacturing a semiconductor device.

SUMMARY OF THE INVENTION An object of the present invention is to provide a filter unit which can efficiently remove bubbles and avoid troublesome workers.

1 is a schematic view of a filter unit according to the prior art.

2 is a schematic view of a filter unit according to the present invention.

FIG. 3 is a timing diagram for describing the operation of the first and second valves shown in FIG. 2.

In order to achieve the above object, the present invention provides a filter for filtering a chemical solution, a chemical solution inlet pipe connected to a lower part of the filter, a chemical solution discharge pipe connected to an upper part of the filter, a bubble discharge pipe connected to an upper part of the filter, It includes a first valve interposed in a predetermined region of the bubble discharge pipe, a second valve for controlling the opening and closing of the first valve, and a pulse signal generator for generating an electrical signal for controlling the opening and closing of the second valve. It features.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a schematic view of a filter unit according to the present invention.

Referring to FIG. 2, the filter unit according to the present invention is connected to a filter F and a lower portion of the filter F, and a chemical solution inlet tube for injecting an unfiltered chemical solution C1 into the filter F. (I), a chemical solution discharge pipe (O) connected to the upper portion of the filter (F) to discharge the filtered chemical solution (C2) from the filter (F), and a filter near the chemical solution discharge pipe (O) ( A bubble discharge pipe VL connected to an upper portion of the F) and providing a passage for discharging the bubble B, a first valve V1 interposed in a predetermined region of the bubble discharge pipe VL, and the first valve ( The air pipe AL, which is a passage connected to V1 and through which air A flows for controlling opening and closing of the first valve V1, is interposed in a predetermined region of the air pipe AL to control the flow of air A. It includes a second valve (V2). The opening and closing of the second valve V2 is controlled by the electrical signal S output from the pulse signal generator G. Preferably, the first valve V1 is an air valve, and the second valve V2 is preferably a solenoid valve.

3 is a timing diagram for explaining the opening and closing of the electrical signal S and the first valve V1 controlling the second valve V2 of FIG. 2.

Referring to FIG. 3, the electrical signal S for controlling the second valve V2 has a constant period T and is in the form of a pulse signal for turning on the second valve V2. The pulse signal has a magnitude of the voltage Von for opening the second valve V2 and the voltage Von is maintained for a predetermined time t _ON . In order to close the second valve V2, the electrical signal S maintains a constant voltage Voff, preferably a ground voltage during the time t _OFF in which the pulse signal is not generated. At this time, the first valve V1 is controlled according to opening and closing of the second valve V2. In other words, air is applied to the first valve V1 through the air pipe AL of FIG. 2 while the pulse signal of the electrical signal S is applied to the second valve V2. Accordingly, the first valve V1 is also opened so that the bubble B collected on the upper portion of the filter F is discharged through the bubble discharge pipe VL. Here, the pulse width t _ON and the period T of the electrical signal S may be determined according to the type of chemical solution injected into the filter F.

The present invention is not limited to the above embodiments, and modifications and improvements are possible at the level of those skilled in the art.

According to the present invention as described above, it is possible to periodically discharge the bubbles generated in the filter, as well as to avoid the trouble of the operator directly controlling the valve. As a result, the efficiency of the filter and the ability to remove bubbles can be maximized.

Claims (3)

A filter for filtering the chemical solution; A chemical solution inlet tube connected to the bottom of the filter; A chemical solution discharge pipe connected to an upper portion of the filter; A bubble discharge pipe connected to an upper portion of the filter; A first valve interposed in a predetermined region of the bubble discharge pipe; A second valve controlling opening and closing of the first valve; And And a pulse signal generator for generating an electrical signal for controlling the opening and closing of the second valve. The filter unit of claim 1, wherein the first valve is an air valve. The filter unit of claim 1, wherein the second valve is a solenoid valve.