Liquid medicine circulation system for wafer etching and etching equipment

Abstract

The invention relates to a liquid medicine circulation system for wafer etching and etching equipment. The liquid medicine circulation system comprises a mixed acid preparation module, a process circulation module and a liquid medicine recovery module. The mixed acid preparation module comprises a stock solution tank with a slender structure and an acid preparation tank connected with the stock solution tank, and a pressure nitrogen inlet is formed in an inlet of the stock solution tank. The process circulation module comprises a process tank connected with the outlet of the acid preparation tank, a large circulation pipeline connected with the outlet of the process tank and of which the tail end flows back into the process tank, a plurality of small circulation pipelines connected with the large circulation pipeline and of which the tail ends flow back into the process tank, and a plurality of process cavities; and the small circulation pipeline is connected with the corresponding process cavity, and a pressure stabilizing valve is arranged at the tail end of the small circulation pipeline. The liquid medicine recovery module comprises two recovery tanks and a recovery pipeline arranged between the recovery tanks and the acid preparation tank. An inlet of a single recovery tank is connected with a plurality of process cavities, and a pressure nitrogen inlet is formed in the inlet.

Description

Technical Field

[0001] The invention relates to the technical field of etching equipment, and in particular to a liquid medicine circulation system and etching equipment for wafer etching. Background Art

[0002] In the single-wafer etching process, in order to improve the process flexibility of a single etching equipment, the process requirements of different products are often met by changing the type of process liquid and the mixing ratio of the liquid. The existing liquid supply system has a large amount of residual liquid in the pipeline after multiple uses. On the one hand, the existing stock liquid tank has a large bottom area, and the liquid transportation of the stock liquid tank and the recovery of the liquid after the process are both directly pumped, resulting in a large amount of residual liquid in the pipeline and a low liquid recovery rate. At the same time, the existing liquid supply is directly delivered to multiple process chambers through the delivery pipeline after mixing and configuration. When the valves on the delivery pipeline are opened and closed, water hammer phenomenon is easily generated, affecting the liquid flow and pressure stability of the pipeline output. Moreover, since the supply branches of multiple process chambers are interconnected, the valves on each pipeline will affect the pressure of the liquid supply of other process chambers when they are opened and closed, thereby affecting the process. Summary of the invention

[0003] The object of the present invention is to provide a liquid medicine circulation system and etching equipment for wafer etching, which can reduce the residual amount of liquid medicine in the original liquid tank by designing the original liquid tank into a slender structure and pressure-transporting the liquid medicine with pressurized nitrogen; by designing a double recovery tank for switching liquid medicine recovery to ensure the continuous operation of the liquid medicine recovery process between the recovery tank and the process chamber, and by air pressure, the liquid medicine in the recovery tank is transported back to the acid preparation tank to improve the liquid medicine recovery rate; by arranging a large circulation pipeline between the process tank and the process chamber to avoid water hammer phenomenon during liquid medicine transportation, so as to better control the flow rate during liquid medicine transportation; by arranging a small circulation pipeline and arranging a pressure-stabilizing valve at the end thereof to improve the pressure stability during liquid medicine transportation, it is ensured that the liquid medicine supply in the etching process is more stable.

[0004] To achieve the above object, according to a first aspect of the present invention, a liquid circulation system for wafer etching is provided, comprising:

[0005] A mixed acid preparation module comprises a raw liquid tank with an elongated structure and an acid preparation tank connected to the raw liquid tank, wherein a pressurized nitrogen inlet for pressure delivery and drying and self-cleaning is arranged at the inlet of the raw liquid tank;

[0006] A process circulation module, comprising a process tank, a large circulation pipeline, a plurality of small circulation pipelines and a plurality of process cavities corresponding to the small circulation pipelines, wherein the process tank is connected to the outlet of the acid preparation tank, the large circulation pipeline is connected to the outlet of the process tank and its end flows back into the process tank, the small circulation pipeline is connected to the large circulation pipeline and its end flows back into the process tank, the small circulation pipeline is connected to the corresponding process cavity to provide liquid medicine to the process cavity, and a pressure stabilizing valve is provided at the end of the small circulation pipeline;

[0007] The liquid medicine recovery module includes two recovery tanks and a recovery pipeline. The inlet of a single recovery tank is connected to the multiple process chambers respectively. The inlet of a single recovery tank is provided with the pressurized nitrogen inlet. The input end of the recovery pipeline is connected to the outlets of the two recovery tanks, and the output end of the recovery pipeline is connected to the inlet of the acid preparation tank.

[0008] Optionally, the drug solution recovery module is configured to recover the drug solution in any one of the two recovery tanks. After one recovery tank is filled with drug solution, it switches to the other recovery tank for drug solution recovery, and at the same time, pressurized nitrogen is injected into one recovery tank to transport the drug solution back to the acid preparation tank to complete the drug solution recovery.

[0009] Optionally, a liquid level sensor is provided on the side of the raw liquid tank.

[0010] Optionally, a first circulation pump is provided at the outlet of the acid preparation tank, a first three-way valve is provided at the output end of the first circulation pump, one output end of the first three-way valve is connected to the inlet of the process tank, and a reflux branch is provided at the other output end of the first three-way valve, and the end of the reflux branch refluxes into the acid preparation tank.

[0011] Optionally, a second circulation pump is provided at the outlet of the process tank, a second three-way valve is provided at the output end of the second circulation pump, and an output end of the second three-way valve is connected to the large circulation pipeline.

[0012] Optionally, a single small circulation pipeline is provided with a primary throttle valve, a secondary throttle valve and a third three-way valve in sequence from the inlet toward the outlet, and an output end of the third three-way valve is connected to the corresponding process chamber.

[0013] Optionally, a fourth three-way valve is provided at the outlet of the process chamber, one output end of the fourth three-way valve is connected to one of the recovery tanks, and the other output end of the fourth three-way valve is connected to another of the recovery tanks.

[0014] Optionally, pure water inlets and air pressure balance inlets are provided at the inlets of the raw liquid tank, the process tank and the recovery tank.

[0015] According to a second aspect of the present invention, an etching device is provided, comprising a chemical solution circulation system for wafer etching.

[0016] The beneficial effects of the present invention are as follows: by designing the original liquid tank into a slender structure and cooperating with pressurized nitrogen to pressure-transfer the liquid medicine to reduce the residual liquid medicine in the original liquid tank; by designing a double recovery tank for switching liquid medicine recovery to ensure the continuous operation of the liquid medicine recovery process between the recovery tank and the process chamber, and by air pressure, the liquid medicine in the recovery tank is transported back to the acid preparation tank to improve the liquid medicine recovery rate; by arranging a large circulation pipeline between the process tank and the process chamber to avoid water hammer phenomenon during liquid medicine transportation, so as to better control the flow rate during liquid medicine transportation, by arranging a small circulation pipeline and arranging a pressure-stabilizing valve at the end thereof to improve the pressure stability during liquid medicine transportation, it is ensured that the liquid medicine supply in the etching process is more stable.

[0017] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic structural diagram of a liquid medicine circulation system for wafer etching according to an embodiment of the present invention;

[0019] Figure 2 A schematic structural diagram of a mixed acid preparation module of a liquid medicine circulation system for wafer etching shown in one embodiment of the present invention;

[0020] Figure 3 A schematic structural diagram of a process circulation module of a liquid circulation system for wafer etching shown in one embodiment of the present invention;

[0021] Figure 4 A schematic structural diagram of a liquid recovery module of a liquid circulation system for wafer etching shown in one embodiment of the present invention;

[0022] In the figure: 1. Mixing and acid preparation module; 11. Raw liquid tank; 111. Pressure nitrogen inlet; 112. Pure water inlet; 113. Air pressure balance port; 114. Drug port; 115. Drain port; 12. Acid preparation tank; 13. Liquid level sensor; 14. First circulation pump; 15. First three-way valve; 16. Reflux branch; 2. Process circulation module; 21. Process tank; 22. Large circulation pipeline; 23. Small circulation pipeline; 231. Primary throttle valve; 232. Secondary throttle valve; 233. Third three-way valve; 24. Process chamber; 25. Pressure regulating valve; 26. Second circulation pump; 27. Second three-way valve; 3. Liquid recovery module; 31. Recovery tank; 32. Recovery pipeline; 33. Fourth three-way valve; 34. Fifth three-way valve. DETAILED DESCRIPTION

[0023] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0026] See also Figures 1 to 4A liquid circulation system for wafer etching shown in a preferred embodiment of the present application includes a mixed acid preparation module 1, a process circulation module 2 and a liquid recovery module 3. The mixed acid preparation module 1 includes a raw liquid tank 11 with a slender structure and an acid preparation tank 12 connected to the raw liquid tank 11. The inlet of the raw liquid tank 11 is provided with a pressurized nitrogen inlet 111 for pressure delivery and drying and self-cleaning. The process circulation module 2 includes a process tank 21, a large circulation pipeline 22, a plurality of small circulation pipelines 23, and a plurality of process chambers 24 corresponding to the small circulation pipelines 23. The process tank 21 is connected to the outlet of the acid preparation tank 12. The large circulation pipeline 22 is connected to the outlet of the process tank 21 and its end flows back into the process tank 21. The small circulation pipeline 23 is connected to the large circulation pipeline 22 and its end flows back into the process tank 21. The small circulation pipeline 23 is connected to the corresponding process chamber 24 to provide liquid medicine to the process chamber 24. A pressure regulating valve 25 is provided at the end of the small circulation pipeline 23. The liquid medicine recovery module 3 includes two recovery tanks 31 and a recovery pipeline 32. The inlet of a single recovery tank 31 is respectively connected to a plurality of process chambers 24. A pressure nitrogen inlet 111 is provided at the inlet of a single recovery tank 31. The input end of the recovery pipeline 32 is connected to the outlets of the two recovery tanks 31. The output end of the recovery pipeline 32 is connected to the inlet of the acid preparation tank 12.

[0027] According to the solution of the embodiment of the present invention, the raw liquid tank 11 is designed to be a slender structure and the liquid medicine is pressure-transported with pressurized nitrogen to reduce the residual liquid medicine in the raw liquid tank 11; the double recovery tank 31 is designed to perform switching liquid medicine recovery to ensure that the liquid medicine recovery process between the recovery tank 31 and the process chamber 24 is continuously running, and the liquid medicine in the recovery tank 31 is transported back to the acid preparation tank 12 by air pressure to improve the liquid medicine recovery rate; a large circulation pipeline 22 is set between the process tank 21 and the process chamber 24 to avoid water hammer during liquid medicine transportation, so as to better control the flow rate during liquid medicine transportation; a small circulation pipeline 23 is set and a pressure-stabilizing valve 25 is set at the end thereof to improve the pressure stability during liquid medicine transportation, so that the small circulation pipelines 23 corresponding to different process chambers 24 will not be affected by the on-off status of the valves in their respective pipelines, thereby ensuring a more stable supply of liquid medicine in the etching process.

[0028] The following is a detailed description with specific embodiments:

[0029] See also Figure 2The inlet of the original liquid tank 11 is provided with a pure water port 112 (DIW), an air pressure balance port 113 (EXH) and a medicine port 114 (CHEM), and the outlet of the original liquid tank 11 is also provided with a drain port 115 (Drain). A liquid level sensor 13 is provided on the side of the original liquid tank 11. By providing the liquid level sensor 13, a higher volume measurement accuracy can be obtained. The outlet of the acid preparation tank 12 is provided with a first circulation pump 14, and the output end of the first circulation pump 14 is provided with a first three-way valve 15, one output end of the first three-way valve 15 is connected to the inlet of the process tank 21, and the other output end of the first three-way valve 15 is provided with a reflux branch 16, and the end of the reflux branch 16 refluxes into the acid preparation tank 12.

[0030] When the mixed acid preparation module 1 is in operation, first, the medicine port 114 and the air pressure balance port 113 are opened to inject external medicine. The liquid level height position is obtained by the liquid level sensor 13, so that the original liquid tank 11 obtains the medicine of the target volume, and the medicine port 114 and the air pressure balance port 113 are closed simultaneously. The pressure nitrogen inlet 111 is opened according to the demand, and the pressure nitrogen is injected, and the medicine in the multiple original liquid tanks 11 is gas-pressurized and transported to the acid preparation tank 12, and the first circulating pump 14 at the bottom of the acid preparation tank 12 is started, and the medicine is extracted, and the first three-way valve 15 is switched to the B port at this moment, and the pump injects the medicine back to the acid preparation tank 12 for circulation mixing, and after the circulation mixing is completed, the first three-way valve 15 is switched to the A port, and the medicine is injected into the process tank 21. As needed, open the drain port 115 and the air pressure balance port 113 to start draining, or open the pure water port 112 and the air pressure balance port 113 to inject pure water to start cleaning, or open the pressurized nitrogen inlet 111 and the air pressure balance port 113 to dry the original liquid tank 11.

[0031] See also Figure 3 The outlet of the process tank 21 is provided with a second circulation pump 26, and the output end of the second circulation pump 26 is provided with a second three-way valve 27, one output end of the second three-way valve 27 is connected to the large circulation pipeline 22, and the other output end of the second three-way valve 27 is used for draining. A single small circulation pipeline 23 is provided with a primary throttle valve 231, a secondary throttle valve 232 and a third three-way valve 233 in sequence from the inlet to the outlet, and one output end of the third three-way valve 233 is connected to the corresponding process chamber 24.

[0032] During the operation of the process circulation module 2, the second circulation pump 26 at the bottom of the process tank 21 is started to extract the liquid medicine, and the second three-way valve 27 is switched to port A, so that the liquid medicine is injected into the large circulation pipeline 22, and then part of the liquid medicine flows back to the process tank 21 along the large circulation pipeline 22 for large circulation, and part of the liquid medicine enters the small circulation pipelines 23 corresponding to the multiple process chambers 24, and passes through the primary throttle valve 231 and the secondary throttle valve 232 in sequence to reach the third three-way valve 233. In the initial state, the third three-way valve 233 is in the open state of the Return port. At this time, the small circulation pipeline 23 performs a small circulation of the liquid medicine. Before the liquid medicine flows back to the process tank 21 through the small circulation pipeline 23, it is stabilized by the pressure regulating valve 25. The third three-way valve 233 is switched to the Supply port as needed, and the liquid medicine is supplied to the process chamber 24 to start the process. Specifically, in this embodiment, there are two process chambers 24, and the pressure regulating valve 25 is an electronic pressure regulating valve. The inlet of the process tank 21 is provided with a pure water inlet 112 for cleaning and drying, a pressurized nitrogen inlet 111 and a pressure balance port 113 .

[0033] See also Figure 4 , the process chamber 24 outlet is provided with a fourth three-way valve 33, one output end of the fourth three-way valve 33 is connected to a recovery tank 31, and the other output end of the fourth three-way valve 33 is connected to another recovery tank 31. A fifth three-way valve 34 is also provided between the fourth three-way valve 33 and the process chamber 24 outlet, and an empty output end of the fifth three-way valve 34 is used for liquid discharge. The liquid medicine recovery module 3 is configured to recover liquid medicine in any one of the two recovery tanks 31. After one recovery tank 31 is filled with liquid medicine, it switches to another recovery tank 31 for liquid medicine recovery, and at the same time, pressurized nitrogen is injected into one recovery tank 31 to transport the liquid medicine back to the acid preparation tank 12 to complete liquid medicine recovery. Since pneumatic conveying is used to recover liquid medicine, pneumatic conveying and recovery can only be started when the liquid medicine fills the entire closed recovery tank 31. At this time, in order to ensure that the recovery process between the process chamber 24 and the recovery tank 31 is uninterrupted, another recovery tank 31 is set, and the fourth three-way valve 33 is switched to connect with another recovery tank 31 to continue to recover the liquid medicine. First, open the A port of the fourth three-way valve 33 so that all the liquid medicine in the process chamber 24 enters the recovery tank 31A. After the recovery tank 31A is fully collected, switch the fourth three-way valve 33 to the B port so that all the liquid medicine in the process chamber 24 is switched to the recovery tank 31B. Open the pressure nitrogen inlet 111 at the recovery tank 31A, and send the liquid medicine back to the acid preparation tank 12 by air pressure transportation to complete the recovery process. Specifically, in this embodiment, the inlet of the recovery tank 31 is also provided with a pure water port 112, an air pressure balance port 113 and a medicine port 114.

[0034] The present invention also provides an etching device, comprising the above-mentioned liquid medicine circulation system for wafer etching.

[0035] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0036] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A liquid medicine circulation system for wafer etching, characterized in that: include: A mixed acid preparation module comprises a raw liquid tank with an elongated structure and an acid preparation tank connected to the raw liquid tank, wherein a pressurized nitrogen inlet for pressure delivery and drying and self-cleaning is arranged at the inlet of the raw liquid tank; A process circulation module, comprising a process tank, a large circulation pipeline, a plurality of small circulation pipelines and a plurality of process cavities corresponding to the small circulation pipelines, wherein the process tank is connected to the outlet of the acid preparation tank, the large circulation pipeline is connected to the outlet of the process tank and its end flows back into the process tank, the small circulation pipeline is connected to the large circulation pipeline and its end flows back into the process tank, the small circulation pipeline is connected to the corresponding process cavity to provide liquid medicine to the process cavity, and a pressure stabilizing valve is provided at the end of the small circulation pipeline; The liquid medicine recovery module includes two recovery tanks and a recovery pipeline. The inlet of a single recovery tank is connected to the multiple process chambers respectively. The inlet of a single recovery tank is provided with the pressurized nitrogen inlet. The input end of the recovery pipeline is connected to the outlets of the two recovery tanks, and the output end of the recovery pipeline is connected to the inlet of the acid preparation tank.

2. The liquid medicine circulation system for wafer etching according to claim 1, characterized in that: The drug solution recovery module is configured to recover the drug solution in any one of the two recovery tanks. After one recovery tank is filled with drug solution, it switches to the other recovery tank for drug solution recovery, and at the same time, pressurized nitrogen is injected into one recovery tank to transport the drug solution back to the acid preparation tank to complete the drug solution recovery.

3. The chemical solution circulation system for wafer etching according to claim 1, characterized in that: A liquid level sensor is arranged on the side of the original liquid tank.

4. The chemical solution circulation system for wafer etching according to claim 1, characterized in that: The outlet of the acid preparation tank is provided with a first circulation pump, the output end of the first circulation pump is provided with a first three-way valve, one output end of the first three-way valve is connected to the inlet of the process tank, the other output end of the first three-way valve is provided with a reflux branch, and the end of the reflux branch refluxes into the acid preparation tank.

5. The liquid chemical circulation system for wafer etching according to claim 1, characterized in that: The process tank outlet is provided with a second circulation pump, the output end of the second circulation pump is provided with a second three-way valve, and an output end of the second three-way valve is connected to the large circulation pipeline.

6. The chemical solution circulation system for wafer etching according to claim 1, characterized in that: A single small circulation pipeline is provided with a primary throttle valve, a secondary throttle valve and a third three-way valve in sequence from the inlet to the outlet, and an output end of the third three-way valve is connected to the corresponding process chamber.

7. The chemical solution circulation system for wafer etching according to claim 1, characterized in that: A fourth three-way valve is disposed at the outlet of the process chamber, one output end of the fourth three-way valve is connected to one of the recovery tanks, and the other output end of the fourth three-way valve is connected to another of the recovery tanks.

8. The chemical solution circulation system for wafer etching according to claim 1, characterized in that: The inlets of the raw liquid tank, the process tank and the recovery tank are provided with pure water inlets and air pressure balance inlets.

9. An etching device, characterized in that: It comprises a chemical solution circulation system for wafer etching as described in any one of claims 1 to 8.

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