A chemical liquid circulation system and an etching device for wafer etching

Abstract

The present invention relates to a chemical liquid circulation system and an etching device for wafer etching. The chemical liquid circulation system includes a mixed acid preparation module, a process circulation module, and a chemical liquid recovery module. The mixed acid preparation module includes a stock solution tank with an elongated structure and an acid mixing tank connected to the stock solution tank. A pressure nitrogen inlet is provided at the inlet of the stock solution tank. The process circulation module includes a process tank connected to the outlet of the acid mixing tank, a large circulation pipeline connected to the outlet of the process tank and having its end refluxed into the process tank, a plurality of small circulation pipelines connected to the large circulation pipeline and having their ends refluxed into the process tank, and a plurality of process cavities. The small circulation pipelines are connected to the corresponding process cavities and a pressure stabilizing valve is provided at their ends. The chemical liquid recovery module includes two recovery tanks and a recovery pipeline provided between the recovery tanks and the acid mixing tank. The inlets of the individual recovery tanks are respectively connected to the plurality of process cavities and a pressure nitrogen inlet is provided at the inlets.

Description

Technical Field

[0001] The present invention relates to the technical field of etching equipment, and particularly relates to a chemical solution circulation system and an 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 types of process chemicals and the mixing ratio of the used chemicals are often changed to meet the process requirements of different products. After multiple uses, the residual amount of chemicals in the pipeline of the existing chemical solution supply system is relatively large. On the one hand, the bottom area of the existing stock solution tank is relatively large, and both the supply of the stock solution in the tank and the recovery of the chemicals after the process adopt direct pumping, resulting in a large amount of chemical residue in the pipeline and a low chemical recovery rate. At the same time, the existing chemical solution supply is directly transported to multiple process chambers through the pipeline after being mixed and configured. When the valves on the pipeline are opened and closed, water hammer phenomenon is likely to occur, affecting the stability of the liquid flow and pressure output by the pipeline. Moreover, since the supply branches of multiple process chambers are interconnected, the opening and closing of the valves on their respective pipelines will affect the pressure of the chemical solution supply in other process chambers, thereby affecting the process. Summary of the Invention

[0003] The purpose of the present invention is to provide a chemical solution circulation system and an etching equipment for wafer etching, which can reduce the residual amount of chemicals in the stock solution tank by designing the stock solution tank into an elongated structure and cooperating with pressurized nitrogen to pressure-transport the chemicals; ensure the continuous operation of the chemical solution recovery process between the recovery tank and the process chamber by designing a dual recovery tank for switching chemical solution recovery, and improve the chemical solution recovery rate by pneumatically transporting the chemicals in the recovery tank back to the acid mixing tank; avoid water hammer phenomenon during chemical solution transportation by setting a large circulation pipeline between the process tank and the process chamber, so as to better control the flow rate during chemical solution transportation, and improve the pressure stability during chemical solution transportation by setting a small circulation pipeline and a pressure stabilizing valve at its end, ensuring more stable chemical solution supply during the etching process.

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

[0005] A mixed acid preparation module, comprising a stock solution tank with an elongated structure and an acid mixing tank connected to the stock solution tank, and a pressurized nitrogen inlet for pressure transportation and dry self-cleaning is arranged at the inlet of the stock solution tank;

[0006] The process cycle module includes 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. 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 returns to the process tank. The small circulation pipelines are connected to the large circulation pipeline and their ends return to the process tank. The small circulation pipelines are connected to the corresponding process cavities to supply liquid medicine to the process cavities, and a pressure stabilizing valve is arranged at the end of the small circulation pipelines.

[0007] The liquid medicine recovery module includes two recovery tanks and a recovery pipeline. The inlets of a single recovery tank are respectively connected to a plurality of the process cavities, and a pressure nitrogen inlet is arranged at the inlet of a single recovery tank. 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 liquid medicine recovery module is set such that any one of the two recovery tanks conducts liquid medicine recovery. After a recovery tank is filled with liquid medicine, it switches to the other recovery tank for liquid medicine recovery while injecting pressure nitrogen into one recovery tank to transport the liquid medicine back to the acid preparation tank to complete the liquid medicine recovery.

[0009] Optionally, a liquid level sensor is arranged on the side of the stock solution tank.

[0010] Optionally, a first circulation pump is arranged at the outlet of the acid preparation tank. 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, and the other output end of the first three-way valve is provided with a reflux branch, and the end of the reflux branch returns to the acid preparation tank.

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

[0012] Optionally, a primary throttle valve, a secondary throttle valve, and a third three-way valve are sequentially arranged on a single small circulation pipeline from the inlet towards the outlet direction, and one output end of the third three-way valve is connected to the corresponding process cavity.

[0013] Optionally, a fourth three-way valve is arranged at the outlet of the process cavity. One output end of the fourth three-way valve is connected to one recovery tank, and the other output end of the fourth three-way valve is connected to the other recovery tank.

[0014] Optionally, a pure water port and a gas pressure balance port are arranged at the inlets of the stock solution tank, the process tank, and the recovery tank.

[0015] According to a second aspect of the present invention, there is provided an etching apparatus including a chemical liquid circulation system for wafer etching.

[0016] The beneficial effects of the present invention are as follows: By designing the stock solution tank into an elongated structure and cooperating with pressurized nitrogen to perform pressure conveyance on the chemical liquid to reduce the residual amount of the chemical liquid in the stock solution tank; By designing a dual recovery tank for switched chemical liquid recovery to ensure the continuous operation of the chemical liquid recovery process between the recovery tank and the process chamber, and conveying the chemical liquid in the recovery tank back to the acid mixing tank by means of air pressure to improve the chemical liquid recovery rate; By providing a large circulation pipeline between the process tank and the process chamber to avoid water hammer phenomenon during chemical liquid conveyance, thereby better controlling the flow rate during chemical liquid conveyance, and by providing a small circulation pipeline and a pressure stabilizing valve at its end to improve the pressure stability during chemical liquid conveyance, ensuring more stable chemical liquid supply during the etching process.

[0017] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly and to be implemented in accordance with the content of the specification, the following will detail the preferred embodiments of the present invention in conjunction with the accompanying drawings as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic structural diagram of a chemical liquid circulation system for wafer etching shown in an embodiment of the present invention;

[0019] Figure 2 It is a schematic structural diagram of a mixed acid preparation module of a chemical liquid circulation system for wafer etching shown in an embodiment of the present invention;

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

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

[0022] In the figure: 1, mixed acid preparation module; 11, stock solution tank; 111, pressurized nitrogen inlet; 112, pure water port; 113, air pressure balance port; 114, reagent port; 115, drain port; 12, acid mixing 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 stabilizing valve; 26, second circulation pump; 27, second three-way valve; 3, chemical liquid recovery module; 31, recovery tank; 32, recovery pipeline; 33, fourth three-way valve; 34, fifth three-way valve. Detailed implementation manners

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0024] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is 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 thus should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0025] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", "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 directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations. In addition, the technical features involved in 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] Please refer to Figures 1 to 4, A chemical 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 chemical liquid recovery module 3. The mixed acid preparation module 1 includes a stock solution tank 11 with an elongated structure and an acid preparation tank 12 connected to the stock solution tank 11. At the inlet of the stock solution tank 11, there is a pressure nitrogen inlet 111 for pressure delivery and dry self-cleaning. The process circulation module 2 includes a process tank 21, a large circulation pipeline 22, multiple small circulation pipelines 23, and multiple process cavities 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 returns to the process tank 21. The small circulation pipelines 23 are connected to the large circulation pipeline 22 and their ends return to the process tank 21. The small circulation pipelines 23 are connected to the corresponding process cavities 24 to supply chemical liquid to the process cavities 24. A pressure stabilizing valve 25 is provided at the end of the small circulation pipeline 23. The chemical liquid recovery module 3 includes two recovery tanks 31 and a recovery pipeline 32. The inlets of a single recovery tank 31 are respectively connected to multiple process cavities 24. At the inlet of a single recovery tank 31, there is a pressure nitrogen inlet 111. The input end of the recovery pipeline 32 is connected to the outlets of the two recovery tanks 31, and 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, by designing the stock solution tank 11 into an elongated structure and cooperating with pressure nitrogen to perform pressure delivery on the chemical liquid to reduce the residual amount of chemical liquid in the stock solution tank 11; by designing two recovery tanks 31 for switched chemical liquid recovery to ensure the continuous operation of the chemical liquid recovery process between the recovery tank 31 and the process cavity 24, and by using the pneumatic method to transport the chemical liquid in the recovery tank 31 back to the acid preparation tank 12 to improve the chemical liquid recovery rate; by arranging a large circulation pipeline 22 between the process tank 21 and the process cavity 24 to avoid the occurrence of water hammer phenomenon during chemical liquid delivery, thereby better controlling the flow rate during chemical liquid delivery, and by arranging small circulation pipelines 23 and providing a pressure stabilizing valve 25 at their ends to improve the pressure stability during chemical liquid delivery, so that the small circulation pipelines 23 corresponding to different process cavities 24 are not affected by the on-off conditions of the valves in their respective pipelines, ensuring more stable chemical liquid supply during the etching process.

[0028] The following will be described in detail with specific embodiments:

[0029] Please refer to Figure 2, a pure water inlet 112 (DIW), a pressure balance inlet 113 (EXH), and a chemical inlet 114 (CHEM) are provided at the inlet of the stock solution tank 11, and a drain outlet 115 (Drain) is further provided at the outlet of the stock solution tank 11. A liquid level sensor 13 is provided on the side of the stock solution tank 11. By providing the liquid level sensor 13, a higher volume measurement accuracy can be obtained. A first circulation pump 14 is provided at the outlet of the acid mixing tank 12. A first three-way valve 15 is provided at the output end of the first circulation pump 14. 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 returns to the acid mixing tank 12.

[0030] During the operation of the mixed acid mixing module 1, first, the chemical inlet 114 and the pressure balance inlet 113 are opened to inject external chemicals. The liquid level height position is obtained through the liquid level sensor 13, so that the stock solution tank 11 obtains the liquid medicine with the target volume, and at the same time, the chemical inlet 114 and the pressure balance inlet 113 are closed. According to the requirement, the pressure nitrogen inlet 111 is opened to inject pressure nitrogen, and the liquid medicine pressure in the plurality of stock solution tanks 11 is transported to the acid mixing tank 12. The first circulation pump 14 at the bottom of the acid mixing tank 12 is started to pump out the liquid medicine. At this time, the first three-way valve 15 is switched to port B, and the pump injects the liquid medicine back into the acid mixing tank 12 for circulating and mixing. After the circulating and mixing is completed, the first three-way valve 15 is switched to port A, and the liquid medicine is injected into the process tank 21. According to the need, the drain outlet 115 and the pressure balance inlet 113 are opened to start draining, or the pure water inlet 112 and the pressure balance inlet 113 are opened to inject pure water to start cleaning, or the pressure nitrogen inlet 111 and the pressure balance inlet 113 are opened to dry the inside of the stock solution tank 11.

[0031] Please refer to Figure 3 , a second circulation pump 26 is provided at the outlet of the process tank 21. A second three-way valve 27 is provided at the output end of the second circulation pump 26. 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 sequentially provided with a primary throttle valve 231, a secondary throttle valve 232, and a third three-way valve 233 from the inlet to the outlet direction. One output end of the third three-way valve 233 is connected to the corresponding process cavity 24.

[0032] During the operation of the process cycle module 2, the second circulation pump 26 at the bottom of the process tank 21 is started to pump out the liquid medicine. The second three-way valve 27 is switched to port A, so that the liquid medicine is injected into the large circulation pipeline 22. Immediately afterwards, part of the liquid medicine flows back to the process tank 21 along the large circulation pipeline 22 for large circulation, and part of it enters the small circulation pipelines 23 corresponding to multiple process cavities 24 respectively, and successively passes through the primary throttle valve 231 and the secondary throttle valve 232 to reach the third three-way valve 233. In the initial state, the third three-way valve 233 is in the state where the Return port is open. At this time, the liquid medicine in the small circulation pipeline 23 undergoes small circulation. Before the liquid medicine flows back to the process tank 21 via the small circulation pipeline 23, the pressure stabilizing valve 25 is used to stabilize the pressure. According to needs, the third three-way valve 233 is switched to the Supply port to supply the liquid medicine into the process cavity 24 to start the process. Specifically, in this embodiment, there are two process cavities 24, and the pressure stabilizing valve 25 is an electronic pressure regulating valve. At the inlet of the process tank 21, there are a pure water port 112 for cleaning and drying, a pressure nitrogen inlet 111, and a pressure balance port 113.

[0033] Please refer to Figure 4 , at the outlet of the process cavity 24, there is 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 outlet of the process cavity 24. One empty output end of the fifth three-way valve 34 is used for liquid drainage. The liquid medicine recovery module 3 is configured such that any one of the two recovery tanks 31 performs liquid medicine recovery. After one recovery tank 31 is filled with liquid medicine, while switching to the other recovery tank 31 for liquid medicine recovery, pressure nitrogen is injected into one recovery tank 31 to transport the liquid medicine back to the acid mixing tank 12 to complete the liquid medicine recovery. Since the liquid medicine is recovered by pneumatic transportation, the pneumatic transportation recovery can only be started after the liquid medicine fills the entire closed recovery tank 31. At this time, in order to ensure the uninterrupted recovery process between the process cavity 24 and the recovery tank 31, another recovery tank 31 is additionally provided, and the fourth three-way valve 33 is switched to be connected to the other recovery tank 31 to continue recovering the liquid medicine. First, open port A of the fourth three-way valve 33 so that all the liquid medicine in the process cavity 24 enters the recovery tank 31A. After the recovery tank 31A is filled and stored, switch the fourth three-way valve 33 to port B so that all the liquid medicine in the process cavity 24 is switched and transferred 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 mixing tank 12 through pneumatic transportation to complete the recovery process. Specifically, in this embodiment, at the inlet of the recovery tank 31, there are also a pure water port 112, a pressure balance port 113, and a chemical agent port 114.

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

[0035] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the various technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as falling within the scope described in this specification.

[0036] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A chemical liquid circulation system for wafer etching, characterized in that, Comprising: A mixed acid preparation module, including a stock solution tank with an elongated structure and an acid preparation tank connected to the stock solution tank. At the inlet of the stock solution tank, there is a pressure nitrogen inlet for pressure transportation and dry self-cleaning; A process circulation module, including 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. 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 returns to the process tank. The small circulation pipelines are connected to the large circulation pipeline and their ends return to the process tank. The small circulation pipelines are connected to the corresponding process cavities to supply liquid medicine to the process cavities. A pressure stabilizing valve is provided at the end of the small circulation pipeline; A liquid medicine recovery module, including two recovery tanks and a recovery pipeline. The inlets of each of the single recovery tanks are respectively connected to a plurality of the process cavities. The pressure nitrogen inlet is provided at the inlet of each of the single recovery tanks. 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 chemical liquid circulation system for wafer etching according to claim 1, characterized in that, The liquid medicine recovery module is configured such that any one of the two recovery tanks performs liquid medicine recovery. After one recovery tank is filled with liquid medicine, it switches to the other recovery tank for liquid medicine recovery. At the same time, pressure nitrogen is injected into one recovery tank to transport the liquid medicine back to the acid preparation tank to complete the liquid medicine recovery.

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

4. The chemical liquid circulation system for wafer etching according to claim 1, wherein A first circulation pump is provided at the outlet of the acid preparation tank. 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, and the other output end of the first three-way valve is provided with a return branch, and the end of the return branch returns to the acid preparation tank.

5. The chemical liquid circulation system for wafer etching according to claim 1, wherein A second circulation pump is provided at the outlet of the process tank. The output end of the second circulation pump is provided with a second three-way valve. One output end of the second three-way valve is connected to the large circulation pipeline.

6. The chemical liquid circulation system for wafer etching according to claim 1, wherein, For each of the single small circulation pipelines, a primary throttle valve, a secondary throttle valve, and a third three-way valve are sequentially arranged from the inlet towards the outlet direction. One output end of the third three-way valve is connected to the corresponding process cavity.

7. The chemical liquid circulation system for wafer etching according to claim 1, wherein A fourth three-way valve is provided at the outlet of the process cavity. 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 the other recovery tank.

8. The chemical liquid circulation system for wafer etching according to claim 1, wherein A pure water port and a pressure balance port are provided at the inlets of the stock solution tank, the process tank, and the recovery tank.

9. An etching device, characterized in that, Comprising the liquid medicine circulation system for wafer etching according to any one of claims 1 to 8.

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