JPH04330400A - Liquid discharging device - Google Patents

Abstract

PURPOSE:To eliminate a need for operation and a power from the outside during other time than a starting by utilizing a siphon during discharge of liquid. CONSTITUTION:A liquid discharging device comprises an inverted J-shaped main line 1 and an exhaust means 2. The main line 1 has a liquid suction part 1a at the one end part immersed in treating liquid 3. The exhaust means 2 is located through a second valve 7b and a water repellent filter 8 in a bypass line 5 branched from a branch point 1b through a flow rate sensor 6 positioned in a level lower than that of the liquid suction port 1a of a treating tank 4. Further, the other end part extending through a first valve 7a forms a liquid discharge port 1c. The second valve 7b is opened, the first valve 7a is closed, and a pressure in the main line 1 is reduced to suck up the treating liquid 3. When the flow rate sensor 6 is operated, the second valve 7b is closed and the first valve 7a is opened, and the main line 1 forms a siphon. The treating liquid 3 is discharged from the suction port 1a located in a high level to the liquid discharge port 1c in a low level.

Description

[Detailed description of the invention]

0001

FIELD OF INDUSTRIAL APPLICATION This invention relates to a liquid draining device, and in particular, when draining various processing liquids stored in a processing tank, a siphon is used and a vacuum exhaust system is used to start the draining operation. The present invention relates to a drainage device that does not require any external operation or power during operation.

[0002] In the manufacturing process of electronic devices, mainly semiconductor devices, for example, various treatment processes performed in the patterning process and cleaning processes to clean the surface, various processing liquids are used depending on the process. ing. Such processing liquids are usually stored in processing tanks and used, but there are many chemicals that are harmful or toxic.

On the other hand, in order to regenerate or waste the processing liquid if it becomes contaminated, it is often done to pump out the processing liquid from the processing tank, so-called draining. How to drain this liquid efficiently, inexpensively, and safely is an important issue from the perspective of reducing manufacturing costs.

0004

2. Description of the Related Art A simple method for draining a processing liquid from a processing tank is to provide a drainage pipe at the bottom of the processing tank and drain the liquid using gravity. By the way, many of the processing liquids are chemically active and highly reactive chemicals. Therefore, treatment tanks are often made of chemically stable materials such as quartz glass or fluorine-based resins. However, these materials are difficult to process and difficult to weld, and it is preferable to avoid providing drainage pipes at the bottom of the processing tank to prevent liquid leakage.

FIG. 4 is an explanatory diagram of an example of a conventional liquid drainage device. In the figure, 3 is a processing liquid, 4 is a processing tank, and 9 is a drainage means. The processing tank 4 is made of quartz glass, fluorine resin, or the like. In the processing tank 4, there are various processes, such as an alkaline aqueous developer solution, a hydrofluoric acid etching solution, and a heated concentrated nitric acid stripping solution in the photolithography process. Various processing liquids 3 are stored, and various processing is performed. The processing tank 4 is configured to withstand these processing liquids 3.

It is preferable that the liquid draining means 9 can drain liquid in a non-contact state where no external force is applied to the processing tank 4 in order to prevent liquid leakage due to damage to the processing tank 4 and from the viewpoint of safety. An aspirator 9a, also called a water pump, is used.

The aspirator 9a is a type of vacuum pump that obtains a reduced pressure by using the discharge pressure of the discharge material 9b such as water, air, or nitrogen gas, and sucks up liquid using this reduced pressure. To operate, simply dip the suction port 9c into the processing liquid 3.
It has been commonly used since the structure is simple. It is often made of glass, but depending on the type of processing liquid 3, it can be made of various materials such as rust-free steel or plastic with excellent chemical resistance.

[0008]

As described above, in the past, aspirators have been frequently used as a simple liquid draining device. However, since it is necessary for the aspirator to constantly leave the discharged material flowing while draining, the cost of the power required for this cannot be avoided. Furthermore, when water is used as the discharge material, there is a disadvantage that the amount of waste liquid increases and the cost of waste liquid treatment cannot be ignored.

[0009] Therefore, the present invention aims to provide a liquid draining device that uses a siphon to drain liquid, starts the draining operation using an exhaust means, and does not require any external operation or power during operation. The purpose is

0010

[Means for solving the problem] The problem mentioned above is the reverse J
The main pipe has a liquid suction port opened near the bottom wall of the processing tank in which the processing liquid is stored at one end, and a middle part of the processing tank outside the tank. It has a bypass pipe connected to the branch point, and a liquid drain opening at the other end lower than the liquid suction port, and the exhaust means is connected to the end of the bypass pipe, This is to reduce the pressure inside the main pipe, and when the pressure inside the main pipe is reduced by the exhaust means, the processing liquid flows from the higher liquid suction port to the lower liquid drain port, forming a siphon. The problem is solved by a drainage device configured to be.

[0011]

[Operation] In contrast to the conventional liquid draining device which used an uneconomical aspirator when draining the processing liquid from the processing tank, the present invention uses the principle of a siphon. In other words, a siphon is defined as a device that moves liquid from a higher level to a lower level, and once the siphon action is initiated, the movement of the liquid is sustained spontaneously by atmospheric pressure. Therefore, in the present invention, the siphon action is started using an exhaust means.

First, an exhaust means is provided in a bypass line branched from the main line, so that the pressure inside the main line separated by a valve can be reduced. Then, the processing liquid is sucked up from the liquid suction port of the main pipe, and the inside of the pipe up to the liquid drainage port opened at a lower position than the liquid suction port is filled with the processing liquid.

[0013] Then, the main pipe becomes a siphon, and even if the exhaust means is shut off and stopped by the valve, the processing liquid sucked up from the liquid suction port can be spontaneously drained through the liquid drain port. Alternatively, a power-operated valve that automatically opens and closes the valve and a flow rate sensor can be used to automatically drain the liquid.

[0014]

[Embodiment] Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2
1 is an explanatory diagram of the operation of FIG. 1, and FIG. 3 is an explanatory diagram of another embodiment of the present invention. In the figure, 1 is the main pipe, 1a is the liquid suction port, 1
b is a branch point, 1c is a drain port, 2 is an exhaust means, 3 is a processing liquid, 4 is a processing tank, 5 is a bypass pipe, 6 is a flow rate sensor, 7
A, 7b, 7c, 7d, and 7e indicate first to fifth valves, and 8 indicates a water-repellent filter, respectively.

Embodiment 1 In FIGS. 1 and 2, a processing tank 4 is a container having a capacity of about 15 to 30 liters, and contains various processing liquids 3 depending on the purpose. The main pipe line 1 and the bypass pipe line 5 are pipes with an inner diameter of about 10 mmφ, and depending on the type of processing liquid 3, quartz glass, vinyl chloride-based or fluorine-based synthetic resin, or rust-free steel are used. .

The main pipe 1 has an inverted J-shape, and one end serves as a liquid suction port 1a, immersed in the processing liquid 3, and opens near the bottom wall of the processing tank 4. Further, a flow rate sensor 6 is provided in the middle part of the processing tank 4 outside the tank at a position lower than the liquid suction port 1a, and below it is a branch point 1b from which a bypass pipe line 5 branches. There is. Further, a first valve 7a is provided below the branch point 1b, and a drain port 1c is opened at the other end of the first valve 7a. Flow rate sensor 6
is adapted to issue a connection/disconnection signal depending on the presence or absence of liquid flowing inside the main pipe 1.

On the other hand, the exhaust means 2 is a so-called rotary vacuum pump, and is provided at the end of the bypass pipe 5 branched from the branch point 1b via a second valve 7b and a water-repellent filter 8. .

[0018] Now, the first valve 7a and the second valve 7b
consists of a power-operated valve that automatically opens and closes in response to an external electrical signal. In addition, the water-repellent filter 8 is made of, for example, a stretched porous fluorinated polymer filtration membrane with excellent chemical resistance.If this filtration membrane is not treated to make it hydrophilic, it will repel aqueous solutions and pass through. It is a filter that only allows gases such as air to pass through.

Now, when the first valve 7a is closed and the second valve 7b is opened to operate the exhaust means 2, the air in the main pipe 1 is exhausted and the pressure is reduced, as shown in FIG. 2(A). The processing liquid 3 is sucked up from the liquid suction port 1a. Next, when the flow rate sensor 6 senses the flow of the processing liquid 3,
A connection/discontinuation signal generated by the flow rate sensor 6 causes the second valve 7b to close and the first valve 7a to open. Here, even if the processing liquid 3 flows into the bypass pipe line 5 before the second valve 7b is closed, the processing liquid 3 will not flow into the exhaust means 2 by the water-repellent filter 8.

In this way, since the flow rate sensor 6 is provided at a lower position than the liquid suction port 1a, when the first valve 7a is opened, the processing liquid 3 flows down from the liquid drain port 1c as shown in FIG. 2(B). and a siphon is formed. Even if the operation of the exhaust means 2 is stopped, the processing liquid 3 continues to be drained spontaneously.

Embodiment 2 In FIG. 3, the main pipe 1 is provided with a third valve 7c above the branch point 1b, and a liquid suction port 1a below the branch point 1b.
A fourth valve 7d is provided at a lower position. Further, the bypass pipe line 5 is provided with a fifth valve 7e near the branch point 1b, and an exhaust means 2 is provided at the end thereof. The volume inside the pipe blocked by the valves 7c, 7d, and 7e is equal to the liquid level of the processing liquid 3 and the third valve 7c.
The position of each valve is determined so that the volume inside the pipe is larger than that of the pipe. Also, the third valve 7
c and the fourth valve 7d are not shown, but the fifth valve 7
This is a power operated valve that automatically opens and closes following the opening and closing of e.

Now, in FIG. 3(A), the third valve 7
With c and fourth valve 7d closed, fifth valve 7e is opened to activate exhaust means 2 to reduce the pressure inside the pipe. Next, when the fifth valve 7e is closed and the operation of the exhaust means 2 is stopped, and the third valve 7c is opened, the processing liquid 3 flows into the main pipe 1 from the liquid suction port 1a as shown in FIG. 3(B). is absorbed. Next, since the fourth valve 7d is provided at a lower position than the liquid suction port 1a, when the fourth valve 7d is opened, the state shown in FIG.
As shown in C), the processing liquid 3 flows down from the drain port 1c,
A siphon is formed. In this way, the treatment liquid 3 continues to be drained spontaneously regardless of the operation of the exhaust means 2.

In the second embodiment, three valves are used, but there is an advantage that the main pipe line 1 can be made into a siphon without using the flow rate sensor 6 or the water-repellent filter 8. In addition, in both Embodiment 1 and Embodiment 2, if the liquid suction port 1a of the main pipe line 1 is exposed from the surface of the processing liquid 3, the siphon effect is released, so the process of draining liquid depending on the position of the liquid suction port 1a The liquid level of liquid 3 can be arbitrarily determined. Further, in the first embodiment, the draining of the processing liquid 3 can be arbitrarily stopped by opening and closing the second valve 7b, and in the second embodiment, by opening and closing the fourth valve 7d.

[0024]

[Effects of the Invention] In the conventional liquid drainage device using an aspirator, it was necessary to constantly discharge a large amount of discharge material such as water or gas, but according to the present invention, when starting to form a siphon, By operating the exhaust means and valve,
After that, drainage can continue spontaneously.

Therefore, the present invention contributes to the manufacturing process of electronic devices such as semiconductor devices by being able to economically and safely drain various processing liquids used in various steps. The effect is great.

[Brief explanation of the drawing]

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

FIG. 2 is an explanatory diagram of the operation of FIG. 1.

FIG. 3 is an explanatory diagram of another embodiment of the present invention.

FIG. 4 is an explanatory diagram of an example of a conventional liquid drainage device.

[Explanation of symbols]

1 Main pipeline 1a Liquid suction port 1b Branch point 1c Drain port 2 Exhaust means 3 Processing liquid 4 Processing tank 5 Bypass pipeline 6 Flow rate sensor 7a First valve 7b Second valve 7c Third valve 7d Fourth valve 7e Fifth valve 8 Water repellent filter

Claims (5)

[Claims] 1. A main pipe line (1) having an inverted J shape and an exhaust means (2), the main pipe line (1) having a processing tank (4) in which a processing liquid (3) is stored at one end. A bypass pipe (5) connected to a liquid suction port (1a) opened near the bottom wall of the processing tank (4) and a branch point (1b) at the middle outside of the processing tank (4).
) and a liquid drain port (1c) opened at a lower position than the liquid suction port (1a) at the other end, and the exhaust means (
2) is connected to the end of the bypass pipe (5) and reduces the pressure inside the main pipe (1);
In the main pipe (1), when the pressure inside the pipe is reduced by the exhaust means (2), the processing liquid (3) flows from the liquid suction port (1a) at a higher level to the drain port (1c) at a lower level. A liquid drainage device characterized in that it forms a siphon. 2. The main pipe (1) is connected to the branch point (
1b), which has a flow rate sensor (6) at a lower position than the liquid suction port (1a) above, and a first valve (7a) below, and the bypass pipe (5) has a second valve. (7b) and a water-repellent filter that does not allow aqueous solutions to pass through (8)
The main pipe line (1) is connected to the exhaust means (2) via the first valve (7a).
When the second valve (7b) is closed and the second valve (7b) is opened to reduce the pressure inside the pipe, when the flow rate sensor (6) is activated, the second valve (7b) is closed and the first valve (7b) is closed.
2. A drainage device according to claim 1, wherein a) is opened to form a siphon. 3. The draining device according to claim 2, wherein the first valve (7a) and the second valve (7b) are power-operated valves that are automatically opened and closed by the flow rate sensor (6). 4. The main pipe (1) is connected to the branch point (
1b), it has a third valve (7c) above and a fourth valve (7d) below, and the bypass pipe (
5) is a fifth valve (7) near the branch point (1b).
e), and the main pipe line (1) is depressurized in the pipe by closing the third valve (7c) and the fourth valve (7d) and opening the fifth valve (7e). After,
When the fifth valve (7e) is closed, the third valve (7e) is closed.
2. The liquid drainage device according to claim 1, wherein the fourth valve (7d) is opened to form a siphon. 5. The exhaust system according to claim 4, wherein the third valve (7c) and the fourth valve (7d) are power-operated valves that automatically open and close following the opening and closing of the fifth valve (7e). liquid equipment.