Silicon wafer corrosion constant temperature system convenient to clean and maintain

Abstract

A silicon wafer corrosion constant-temperature system convenient to clean and maintain comprises a constant-temperature tank and a corrosion tank located above the constant-temperature tank, the corrosion tank and the constant-temperature tank are connected through an acid inlet pipe and an acid discharge pipe, a chemical pump used for introducing acid in the constant-temperature tank into the corrosion tank is arranged on the acid inlet pipe, a first valve is arranged on the acid inlet pipe, and a second valve is arranged on the first valve. A first discharge pipe is connected to the part, above the first valve, of the acid inlet pipe, and a second valve is arranged on the first discharge pipe; a third valve is arranged on the acid discharge pipe, a second discharge pipe is connected to the acid discharge pipe above the third valve, and a fourth valve is arranged on the second discharge pipe. The device is used for greatly reducing the cleaning and maintenance difficulty of the heavy corrosion tank part of the system.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor material processing technology, specifically a constant temperature system for silicon wafer etching that is easy to clean and maintain. Background Technology

[0002] Both CN201911390270.7 and CN201922431204.1, submitted by the applicant, disclose a temperature control system for a chemical solution during silicon wafer etching. This system includes a constant-temperature bath and an etching tank located above the constant-temperature bath. The constant-temperature bath and the etching tank are connected by an acid inlet pipe and an acid outlet pipe, and a chemical pump is installed on the acid inlet pipe. The etching tank contains acid solution for immersing and etching the silicon wafer. The constant-temperature bath is thermally connected to a hot water tank and a cold water tank, thereby allowing the constant-temperature acid to be pumped into the etching tank. The acid in the etching tank then flows into the constant-temperature bath through the acid outlet pipe under gravity, thus achieving a constant temperature state for the acid solution in the etching tank through circulation.

[0003] During the implementation of the system, it was discovered that when equipment in the corrosion tank malfunctioned, personnel needed to drain the acid from the corrosion tank into a constant temperature bath, and the corrosion tank had to be rinsed with water before entering for maintenance. However, to prevent large amounts of rinsing water from the corrosion tank from flowing into the constant temperature bath and causing the acid concentration in the constant temperature bath to become too low to be usable, the acid needed to be temporarily stored in a container after being drained into the constant temperature bath and before rinsing the corrosion tank. This necessitated the installation of an external acid container, making the maintenance process time-consuming and labor-intensive, and posing a safety hazard of acid leakage. Utility Model Content

[0004] The present invention aims to provide a constant temperature system for silicon wafer etching that is easy to clean and maintain, and significantly reduces the difficulty of cleaning and maintaining the heavily etched tank part of the system.

[0005] To solve the above technical problems, the specific solution adopted by this utility model is as follows: a constant temperature system for silicon wafer etching that is easy to clean and maintain, including a constant temperature bath and an etching tank located above the constant temperature bath. The etching tank and the constant temperature bath are connected by an acid inlet pipe and an acid outlet pipe. A chemical pump for introducing acid from the constant temperature bath into the etching tank is provided on the acid inlet pipe. A first valve is provided on the acid inlet pipe, and a first outlet pipe is connected to the acid inlet pipe above the first valve. A second valve is provided on the first outlet pipe. A third valve is provided on the acid outlet pipe, and a second outlet pipe is connected to the acid outlet pipe above the third valve. A fourth valve is provided on the second outlet pipe.

[0006] Preferably, both the first and second discharge pipes are inclined.

[0007] Preferably, the angle between the first discharge pipe and the second discharge pipe and the horizontal direction is 60°-70°.

[0008] Preferably, the length of the pipe on the acid inlet pipe located between the first discharge pipe and the first valve is no more than 15cm; the length of the pipe on the acid discharge pipe located between the second discharge pipe and the third valve is no more than 15cm.

[0009] Preferably, the acid inlet pipe, acid outlet pipe, first discharge pipe, and second discharge pipe are all made of PVC.

[0010] Preferably, the diameters of the acid inlet pipe, acid outlet pipe, first discharge pipe, and second discharge pipe are all 2 inches.

[0011] Preferably, the first valve, the second valve, the third valve, and the fourth valve are all pneumatic valves.

[0012] Preferably, the valve bodies of the first valve, the second valve, the third valve, and the fourth valve are all made of PVC, the valve cores are all made of fluororubber, and the sealing surfaces are all made of polytetrafluoroethylene.

[0013] The constant temperature system of this invention is equipped with a first valve, a first discharge pipe, and a second valve on the acid inlet pipe, and a third valve, a second discharge pipe, and a fourth valve on the acid outlet pipe. This allows the first and third valves to be opened before maintenance of the corrosion tank equipment to allow the acid to flow back into the constant temperature tank normally. Then, with the first and third valves closed and the second and fourth valves open, flushing is performed, allowing the flushing water to be discharged through the first and second discharge pipes instead of entering the constant temperature tank in large quantities. This eliminates the need to temporarily extract and store the acid from the constant temperature tank, significantly improving the cleaning and maintenance efficiency of this invention, saving considerable manpower and resources, and reducing the risk of acid leakage because it eliminates the need for external acid extraction. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model;

[0015] The markings in the diagram are: 1. Corrosion tank, 2. Chemical pump, 3. First discharge pipe, 4. Second valve, 5. First valve, 6. Acid inlet pipe, 7. Thermostatic bath, 8. Acid discharge pipe, 9. Third valve, 10. Fourth valve, 11. Second discharge pipe. Detailed Implementation

[0016] This invention discloses a constant-temperature system for silicon wafer etching that is easy to clean and maintain. The main structure is the same as that of the constant-temperature systems mentioned in the background art, both including an etching tank 1 for holding acid to etch the silicon wafer and a constant-temperature tank 7 for maintaining a specific temperature of the acid. The constant-temperature tank 7 and the etching tank 1 are connected by an acid inlet pipe 6 and an acid outlet pipe 8 spaced apart. The acid in the constant-temperature tank 7 is introduced into the etching tank 1 through the acid inlet pipe 6 and a chemical pump 2 mounted on the acid inlet pipe 6. The acid in the etching tank 1 is discharged into the constant-temperature tank 7 through the acid outlet pipe 8 under gravity, thereby maintaining the specific temperature of the acid in the etching tank 1 through continuous circulation.

[0017] Based on the above technical solutions, in order to facilitate the maintenance of the equipment in corrosion tank 1, the present invention has made the following improvements. Figure 1 The improvements shown:

[0018] On the acid inlet pipe 6, located below the chemical pump 2, a first discharge pipe 3 and a first valve 5 are sequentially arranged from top to bottom, and a second valve 4 is installed on the first discharge pipe 3. On the acid discharge pipe 8, a second discharge pipe 11 and a third valve 9 are sequentially arranged from top to bottom, and a fourth valve 10 is installed on the second discharge pipe 11.

[0019] Based on the above technical solution, during normal operation, this utility model opens the first valve 5 and the third valve 9, and closes the second valve 4 and the fourth valve 10 to maintain acid circulation. During maintenance, the chemical pump 2 is shut off, allowing the acid in the acid corrosion tank 1 to flow into the constant temperature tank 7 via the acid inlet pipe 6 and the acid outlet pipe 8 under gravity. Then, the first valve 5 and the third valve 9 are closed, and the second valve 4 and the fourth valve 10 are opened to flush the equipment in the corrosion tank 1. The first discharge pipe 3 and the second discharge pipe 11 are connected to an external waste liquid tank, thus directing the flushing water into the waste liquid tank. After flushing, personnel can enter the corrosion tank 1 to perform maintenance work on the relevant equipment. After maintenance is completed, the first valve 5 and the third valve 9 are reopened, and the second valve 4 and the fourth valve 10 are closed to resume production.

[0020] To facilitate the discharge of flushing water, in this embodiment, both the first discharge pipe 3 and the second discharge pipe 11 are inclined, with an angle of 60°-70° to the horizontal direction being preferable. It should be noted that... Figure 1 The first discharge pipe 3 and the second discharge pipe 11 in the figure are only shown to illustrate the structure and are not tilted.

[0021] To minimize the amount of rinsing water entering the constant temperature bath 7 and to facilitate the installation and assembly of the first discharge pipe 3, the second discharge pipe 11, the first valve 5, and the third valve 9, in this embodiment, the length of the inlet pipe 6 between the first discharge pipe 3 and the first valve 5 is no more than 15cm; the length of the outlet pipe 8 between the second discharge pipe 11 and the third valve 9 is no more than 15cm; and the diameters of the inlet pipe 6, the outlet pipe 8, the first discharge pipe 3, and the second discharge pipe 11 are all 2 inches.

[0022] To achieve corrosion resistance, the acid inlet pipe 6, acid outlet pipe 8, first discharge pipe 3, and second discharge pipe 11 in this embodiment are all PVC pipes. The valve bodies of the first valve 5, second valve 4, third valve 9, and fourth valve 10 are all made of PVC, the valve cores are all made of fluororubber, and the sealing surfaces are all made of polytetrafluoroethylene. Furthermore, the first valve 5, second valve 4, third valve 9, and fourth valve 10 are all pneumatic valves for remote control.

Claims

1. A constant temperature system for etching silicon wafers that is easy to clean and maintain, comprising a constant temperature bath (7) and an etching tank (1) located above the constant temperature bath (7), the etching tank (1) and the constant temperature bath (7) being connected by an acid inlet pipe (6) and an acid outlet pipe (8), and a chemical pump (2) for introducing acid from the constant temperature bath (7) into the etching tank (1) is provided on the acid inlet pipe (6), characterized in that: A first valve (5) is provided on the acid inlet pipe (6), and a first discharge pipe (3) is connected to the acid inlet pipe (6) above the first valve (5). A second valve (4) is provided on the first discharge pipe (3). A third valve (9) is provided on the acid discharge pipe (8), and a second discharge pipe (11) is connected to the acid discharge pipe (8) above the third valve (9). A fourth valve (10) is provided on the second discharge pipe (11).

2. The constant temperature system for silicon wafer etching that is easy to clean and maintain as described in claim 1, characterized in that: The first discharge pipe (3) and the second discharge pipe (11) are both distributed at an angle.

3. The constant temperature system for silicon wafer etching that is easy to clean and maintain as described in claim 2, characterized in that: The angle between the first discharge pipe (3) and the second discharge pipe (11) and the horizontal direction is 60°-70°.

4. The constant temperature system for silicon wafer etching that is easy to clean and maintain as described in claim 1, characterized in that: The length of the pipe between the first discharge pipe (3) and the first valve (5) on the acid inlet pipe (6) shall not exceed 15cm; the length of the pipe between the second discharge pipe (11) and the third valve (9) on the acid outlet pipe (8) shall not exceed 15cm.

5. The constant temperature system for silicon wafer etching that is easy to clean and maintain as described in claim 1, characterized in that: The acid inlet pipe (6), acid outlet pipe (8), first discharge pipe (3) and second discharge pipe (11) are all made of PVC.

6. The constant temperature system for silicon wafer etching that is easy to clean and maintain as described in claim 1, characterized in that: The diameters of the acid inlet pipe (6), the acid outlet pipe (8), the first discharge pipe (3), and the second discharge pipe (11) are all 2 inches.

7. The constant temperature system for silicon wafer etching that is easy to clean and maintain as described in claim 1, characterized in that: The first valve (5), the second valve (4), the third valve (9), and the fourth valve (10) are all pneumatic valves.

8. The constant temperature system for silicon wafer etching that is easy to clean and maintain as described in claim 1, characterized in that: The valve bodies of the first valve (5), the second valve (4), the third valve (9), and the fourth valve (10) are all made of PVC, the valve cores are all made of fluororubber, and the sealing surfaces are all made of polytetrafluoroethylene.

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