Wet etching device

Abstract

The invention discloses a wet etching device. The wet etching device comprises an etching groove; the water inlet unit selectively introduces deionized water in the water supply device into the etching groove; the etching liquid injection unit selectively injects etching liquid into the etching groove; the concentration detection structure is used for detecting the etching liquid concentration information of the etching liquid in the etching groove; the control unit is configured to control the working state of the water inlet unit and the working state of the etching liquid injection unit according to the etching liquid concentration information. When the wet etching device is used for etching the to-be-etched part, the concentration of the etching liquid in the wet etching device can be detected in real time, the concentration of the etching liquid in the wet etching device can be found in time when not meeting the etching requirement, the yield of the to-be-etched part can be improved, and in addition, the yield of the to-be-etched part can be improved. According to the wet etching device, high-concentration etching liquid or deionized water does not need to be manually added into the wet etching device, the risk of splashing of the etching liquid is reduced, in addition, the wet etching device does not need to be shut down to detect the concentration of the etching liquid, and continuous production and manufacturing are facilitated.

Description

Technical Field

[0001] This invention relates to the field of semiconductor micro-nano fabrication technology, and in particular to a wet etching apparatus. Background Technology

[0002] In related technologies, wet etching is a crucial process in the manufacturing of semiconductor chips, microelectromechanical systems (MEMS), and optoelectronic devices. Wet etching equipment is used to etch the workpiece, which can be a Si wafer, glass plate, etc. The concentration of the etching solution within the wet etching equipment is a core parameter affecting the etching rate, selectivity, and etching uniformity. Fluctuations in the etching solution concentration directly lead to changes in the etching rate, easily causing over-etching or under-etching of the workpiece, thus affecting its performance.

[0003] In existing wet etching equipment, during the continuous etching of the workpiece, the concentration of the etching solution in the equipment continuously decreases due to the carrying of the robotic arm, the evaporation of the etching solution, and the consumption of silicon wafers, glass plates and other materials by chemical reactions with the etching solution. This leads to unstable etching rate and a decrease in the yield of the workpiece.

[0004] Furthermore, wet etching equipment uses offline sampling of the etching solution to detect its concentration. Based on the detection results, high-concentration etching solution or deionized water is manually added to the wet etching equipment to adjust the concentration to a suitable level. However, this method requires the wet etching equipment to be shut down to detect the etching solution concentration, which is not conducive to continuous production. At the same time, the etching solution concentration in the wet etching equipment cannot be detected in real time, and it is not easy to detect when the etching solution concentration in the wet etching equipment does not meet the etching requirements, which affects the yield of the parts to be etched. In addition, manually adding high-concentration etching solution or deionized water to the wet etching equipment can easily lead to the danger of etching solution splashing. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, one objective of this invention is to provide a wet etching apparatus that can monitor the concentration of the etching solution within the apparatus in real time. When the etching solution concentration does not meet the etching requirements, it can be detected promptly, which is beneficial for improving the yield of the workpiece to be etched. Furthermore, it eliminates the need to manually add high-concentration etching solution or deionized water to the wet etching apparatus, reducing the risk of etching solution splashing. Additionally, it eliminates the need to stop the wet etching apparatus to monitor the etching solution concentration, which is beneficial for continuous production.

[0006] A wet etching apparatus according to an embodiment of the present invention includes: Etching tank: The etching tank is used to hold etching solution and also to place the workpiece to be etched. The water inlet unit is connected to the etching tank and is used to connect to the water supply device. The water inlet unit selectively introduces deionized water from the water supply device into the etching tank. An etching solution injection unit is connected to an etching tank and selectively injects etching solution into the etching tank. The concentration detection structure is located inside the etching tank and is used to detect the concentration information of the etching solution in the etching tank. The control unit is communicatively connected to the concentration detection structure, the water inlet unit, and the etching solution injection unit. The control unit is configured to control the working status of the water inlet unit and the etching solution injection unit based on the etching solution concentration information.

[0007] The wet etching apparatus according to embodiments of the present invention can detect the concentration of the etching solution in the wet etching apparatus in real time. When the concentration of the etching solution in the wet etching apparatus does not meet the etching requirements, it can be detected in time, which is beneficial to improving the yield of the workpiece to be etched. In addition, it is not necessary to manually add high-concentration etching solution or deionized water to the wet etching apparatus, reducing the risk of etching solution splashing. Furthermore, it is not necessary to stop the wet etching apparatus to detect the etching solution concentration, which is beneficial to continuous production.

[0008] In some examples of the present invention, the control unit is also configured to control the water inlet unit to introduce a fixed amount of deionized water into the etching tank based on the etching solution concentration information.

[0009] In some examples of the present invention, the water inlet unit includes: a water inlet pipe and a first control valve. The water inlet of the water inlet pipe is used to communicate with a water supply device, and the water outlet of the water inlet pipe is communicated with an etching groove. The first control valve is located in the water inlet pipe and is communicatively connected to a control unit. The control unit controls the opening and closing of the water inlet and the water outlet through the first control valve.

[0010] In some examples of the present invention, the water inlet unit further includes: a flow detection element, which is disposed in the water inlet pipe and is used to detect the flow rate information of deionized water in the water inlet pipe; a control unit is communicatively connected to the flow detection element; and the control unit is configured to control the first control valve to close according to the deionized water flow rate information.

[0011] In some examples of the present invention, the flow detection element is located upstream of the first control valve along the flow direction of deionized water in the inlet pipe.

[0012] In some examples of the present invention, the control unit is also configured to control the etching solution injection unit to inject a fixed amount of etching solution into the etching tank based on the etching solution concentration information.

[0013] In some examples of the present invention, the etching fluid injection unit includes: a storage container and a second control valve. The storage container is used to store etching fluid, and the second control valve is disposed on the communication path between the storage container and the etching tank and is communicatively connected to the control unit. The control unit controls the on / off state of the storage container and the etching tank through the second control valve.

[0014] In some examples of the present invention, the etching fluid injection unit further includes a drive pump, which is located on the communication path between the storage container and the etching tank and is communicatively connected to the control unit, which can control the drive pump to be turned on or off.

[0015] In some examples of the present invention, the etching fluid injection unit further includes: an etching fluid inlet pipe, the inlet of which is connected to a storage container, the outlet of which is connected to an etching tank, and a second control valve and a drive pump both located in the etching fluid inlet pipe.

[0016] In some examples of the present invention, the driving pump is a metering pump.

[0017] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of a wet etching apparatus according to an embodiment of the present invention.

[0019] Figure label: Wet etching apparatus 100; Etching groove 10; Accommodation space 11; Water inlet unit 20; water inlet pipe 21; first control valve 22; flow detection element 23; Etching fluid injection unit 30; storage container 31; second control valve 32; drive pump 33; etching fluid inlet pipe 34; Concentration detection structure 40; Control unit 50. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0021] The following is for reference. Figure 1A wet etching apparatus 100 according to an embodiment of the present invention is described.

[0022] like Figure 1 As shown, the wet etching apparatus 100 according to an embodiment of the present invention includes: The etching tank 10 is used to hold etching solution and also to place the workpiece to be etched. Water inlet unit 20 is connected to etching tank 10. Water inlet unit 20 is used to connect to water supply device. Water inlet unit 20 selectively introduces deionized water from water supply device into etching tank 10. Etching solution injection unit 30 is connected to etching tank 10 and selectively injects etching solution into etching tank 10. Concentration detection structure 40 is disposed in etching tank 10 and is used to detect the concentration information of etching solution in etching tank 10. The control unit 50 is communicatively connected to the concentration detection structure 40, the water inlet unit 20, and the etching solution injection unit 30. The control unit 50 is configured to control the working state of the water inlet unit 20 and the working state of the etching solution injection unit 30 according to the etching solution concentration information.

[0023] The wet etching apparatus 100 includes an etching tank 10, a water inlet unit 20, an etching solution injection unit 30, a concentration detection structure 40, and a control unit 50. The etching tank 10 has a receiving space 11 for holding the etching solution. During the etching process of the wet etching apparatus 100, the workpiece is placed in the receiving space 11 of the etching tank 10, and can be immersed in the etching solution within the receiving space 11. This application uses a Si wafer as an example to illustrate the process.

[0024] The water inlet unit 20 has a first inlet and a first outlet. The first inlet is connected to the water supply device, and the first outlet is connected to the etching tank 10. The water inlet unit 20 selectively connects the first inlet and the first outlet. When the first inlet and the first outlet are connected, deionized water in the water supply device flows into the water inlet unit 20 through the first inlet and flows along the water inlet unit 20 to the first outlet. The deionized water then flows into the etching tank 10 through the first outlet. When the first inlet and the first outlet are not connected, the deionized water in the water supply device cannot flow into the etching tank 10 along the water inlet unit 20. As an example, the water inlet unit 20 has a first solenoid valve, which can be an electric regulating valve. The first solenoid valve is located on the communication path between the first inlet and the first outlet. By opening or closing the first solenoid valve, the water inlet unit 20 selectively connects the first inlet and the first outlet.

[0025] The etching solution injection unit 30 is connected to the etching tank 10. The etching solution injection unit 30 can store a certain amount of high-concentration etching solution, which is added to the etching tank 10 at appropriate times and in appropriate amounts. The etching solution injection unit 30 has a second outlet, which can be directly connected to the etching tank 10 or indirectly connected to the etching tank 10 via a pipeline. The etching solution injection unit 30 can inject etching solution into the etching tank 10, or it can choose not to inject etching solution into the etching tank 10. Depending on actual working requirements, the etching solution injection unit 30 selectively injects etching solution into the etching tank 10. As an example, the etching solution injection unit 30 also has a second solenoid valve and a storage container 31 for storing etching solution. The second solenoid valve is disposed on the communication path between the storage container 31 and the second outlet. By opening or closing the second solenoid valve, the storage container 31 and the second outlet are selectively connected or disconnected. When the storage container 31 and the second outlet are connected, the etching solution in the storage container 31 flows into the etching tank 10 from the second outlet. When the storage container 31 and the second outlet are not connected, the etching solution in the storage container 31 cannot flow into the etching tank 10.

[0026] The concentration detection structure 40 can be a concentration monitor, concentration meter, etc. The concentration detection structure 40 is set in the etching tank 10 and immersed in the etching solution in the containing space 11. The concentration detection structure 40 can detect the etching solution concentration information in the etching tank 10 in real time. The concentration detection structure 40 feeds back the etching solution concentration data to the control unit 50 in real time by measuring the pH value of the etching solution.

[0027] The control unit 50 can be a controller; this application uses a PLC controller as an example for illustration. The control unit 50 is communicatively connected to the concentration detection structure 40, the water inlet unit 20, and the etching solution injection unit 30. The control unit 50 is connected to these components via a CAN bus, and can also be wirelessly connected, thus achieving communicative connectivity between the control unit 50 and these components. The control unit 50 can acquire the etching solution concentration information detected by the concentration detection structure 40 in real time.

[0028] The control unit 50 can control the water inlet unit 20 to operate, so that the water inlet unit 20 connects the first inlet and the first outlet to introduce deionized water from the water supply device into the etching tank 10. The control unit 50 can also control the water inlet unit 20 to operate, so that the first inlet and the first outlet are not connected, and at this time the water inlet unit 20 does not introduce deionized water from the water supply device into the etching tank 10.

[0029] The control unit 50 can control the etching solution injection unit 30 to operate, so that the storage container 31 and the second outlet are connected, thereby injecting etching solution into the etching tank 10 by the etching solution injection unit 30. The control unit 50 can also control the etching solution injection unit 30 to operate, so that the storage container 31 and the second outlet are disconnected (i.e. not connected), and the etching solution injection unit 30 does not inject etching solution into the etching tank 10 at this time.

[0030] Specifically, after starting the wet etching apparatus 100, the preset concentration information of the etching solution in the etching tank 10 is input into the wet etching apparatus 100, and the preset concentration information is stored in the control unit 50. The preset concentration information is a range value, with an upper limit and a lower limit. The control unit 50 acquires the etching solution concentration information detected by the concentration detection structure 40 in real time. At the same time, the control unit 50 compares the etching solution concentration information detected by the concentration detection structure 40 with the preset concentration information, and determines the next operation based on the comparison result.

[0031] If the concentration information of the etching solution detected by the concentration detection structure 40 is within the preset concentration information range, the wet etching device 100 is started to standby state, the water inlet unit 20 does not introduce deionized water from the water supply device into the etching tank 10, and the etching solution injection unit 30 does not inject etching solution into the etching tank 10.

[0032] If the etching solution concentration detected by the concentration detection structure 40 is greater than the preset concentration information, the etching solution concentration in the etching tank 10 is too high. The control unit 50 controls the water inlet unit 20 to work and introduce deionized water from the water supply device into the etching tank 10, so that the etching solution concentration in the etching tank 10 is within the preset concentration information range, thereby adjusting the etching solution concentration in the etching tank 10 to a suitable concentration.

[0033] If the etching solution concentration detected by the concentration detection structure 40 is less than the preset concentration information, the etching solution concentration in the etching tank 10 is too low. The control unit 50 controls the etching solution injection unit 30 to work, so that the etching solution injection unit 30 injects etching solution into the etching tank 10, so that the etching solution concentration in the etching tank 10 is within the preset concentration information range, thereby adjusting the etching solution concentration in the etching tank 10 to a suitable concentration.

[0034] When etching the workpiece using the wet etching apparatus 100 of this application, the concentration detection structure 40 detects the etching solution concentration information in the etching tank 10 in real time, and the control unit 50 acquires the etching solution concentration information detected by the concentration detection structure 40 in real time. This enables rapid response to the etching solution concentration in the etching tank 10, and can promptly detect when the etching solution concentration in the etching tank 10 is too high or too low. The control unit 50 can control the water inlet unit 20 or the etching solution injection unit 30 to introduce deionized water or inject etching solution into the etching tank 10, so that the etching solution concentration in the etching tank 10 is maintained within the preset concentration information range. This is beneficial to improving the etching rate, selectivity, and etching uniformity of the workpiece, and reduces the risk of excessively high or low etching solution concentration in the etching tank 10. The low risk of quality defects in the etched parts is beneficial to improving the yield rate. Furthermore, the wet etching apparatus 100 operates in a fully automated manner, requiring no manual intervention throughout the entire control process. It eliminates the need to manually add high-concentration etching solution or deionized water to the etching tank 10, reducing the labor intensity and chemical exposure risks for operators. Simultaneously, the wet etching apparatus 100 does not require shutdown to check the etching solution concentration, facilitating continuous production and improving production efficiency. In addition, the wet etching apparatus 100 offers high control precision, employing closed-loop feedback control logic to maintain the etching solution concentration in the etching tank 10 within the upper and lower limits of preset concentration information. This avoids drastic fluctuations in the etching solution concentration within the etching tank 10, significantly improving the stability of the etching process and product consistency.

[0035] Therefore, by etching the workpiece using the wet etching apparatus 100 of this application, the concentration of the etching solution within the wet etching apparatus 100 can be detected in real time. If the concentration of the etching solution within the wet etching apparatus 100 does not meet the etching requirements, it can be detected in a timely manner, which is beneficial to improving the yield of the workpiece. Furthermore, it is not necessary to manually add high-concentration etching solution or deionized water to the wet etching apparatus 100, reducing the risk of etching solution splashing. In addition, it is not necessary to stop the wet etching apparatus 100 to detect the etching solution concentration, which is beneficial to continuous production.

[0036] In some embodiments of the present invention, a circulation pump may be installed within the accommodating space 11 of the etching tank 10. The circulation pump can be communicatively connected to the control unit 50, which can control the circulation pump to start or stop. When the circulation pump is turned on, it can drive the etching solution within the accommodating space 11 to flow, thereby facilitating the uniform mixing of the etching solution and deionized water within the etching tank 10. Furthermore, adding a high concentration of etching solution or deionized water to the etching tank 10 and then turning on the circulation pump can improve the mixing efficiency of the etching solution and deionized water, enabling them to mix quickly and uniformly.

[0037] In some embodiments of the present invention, the control unit 50 is further configured to control the water inlet unit 20 to introduce a fixed amount of deionized water into the etching tank 10 according to the etching solution concentration information.

[0038] The control unit 50 stores a control algorithm. When the etching solution concentration detected by the concentration detection structure 40 is greater than the preset concentration, the control unit 50 obtains the etching solution concentration detected by the concentration detection structure 40. The control unit 50 calculates the amount of deionized water that needs to be added to the etching tank 10 at this time through the control algorithm. Then, the control unit 50 controls the water inlet unit 20 to introduce a fixed amount of deionized water into the etching tank 10, adjusting the etching solution concentration in the etching tank 10 to a suitable concentration. This setting can accurately add the amount of deionized water into the etching tank 10 according to the etching solution concentration detected by the concentration detection structure 40, reducing the risk of introducing too much or too little deionized water into the etching tank 10, and accurately adjusting the etching solution concentration in the etching tank 10 to a suitable concentration.

[0039] As an example, after the first solenoid valve is opened, the amount of deionized water introduced into the etching tank 10 by the water inlet unit 20 per unit time is constant. The control unit 50 calculates the opening time required for the first solenoid valve through the control algorithm based on the etching solution concentration information detected by the concentration detection structure 40. By controlling the opening time of the first solenoid valve through the control unit 50, the effect of controlling the water inlet unit 20 to introduce a fixed amount of deionized water into the etching tank 10 is achieved.

[0040] In some embodiments of the present invention, such as Figure 1 As shown, the water inlet unit 20 includes: a water inlet pipe 21 and a first control valve 22. The water inlet of the water inlet pipe 21 is used to connect with the water supply device, and the water outlet of the water inlet pipe 21 is connected with the etching groove 10. The first control valve 22 is located on the water inlet pipe 21 and is communicatively connected to the control unit 50. The control unit 50 controls the opening and closing of the water inlet and the water outlet through the first control valve 22.

[0041] The water inlet pipe 21 has a water inlet (i.e., the first inlet mentioned above) and a water outlet (i.e., the first outlet mentioned above). The water inlet pipe 21 can be made of polypropylene material. Polypropylene material is lightweight and high-strength, which is beneficial for the lightweight design of the wet etching apparatus 100. At the same time, polypropylene material is corrosion-resistant, reducing the risk of acid and alkali corrosion to the water inlet pipe 21 and helping to extend the service life of the water inlet pipe 21. The water inlet of the water inlet pipe 21 is connected to the water supply device, and the water outlet of the water inlet pipe 21 is connected to the etching tank 10. The water inlet pipe 21 is used to connect the etching tank 10 and the water supply device. The first control valve 22 (i.e., the first solenoid valve in the above embodiment) is set on the water inlet pipe 21. When the first control valve 22 is open, the water inlet pipe 21 is open, and the deionized water in the water supply device can flow into the etching tank 10 along the water inlet pipe 21. When the first control valve 22 is closed, the water inlet pipe 21 is closed, and the deionized water in the water supply device cannot flow into the etching tank 10 along the water inlet pipe 21.

[0042] The first control valve 22 is communicatively connected to the control unit 50. When the etching solution concentration detected by the concentration detection structure 40 is greater than the preset concentration, the control unit 50 controls the first control valve 22 to open, introducing deionized water from the water supply device into the etching tank 10, thus adjusting the etching solution concentration in the etching tank 10 to a suitable level. When the etching solution concentration detected by the concentration detection structure 40 is less than the preset concentration, the control unit 50 controls the first control valve 22 to close, preventing the introduction of deionized water from the water supply device into the etching tank 10 and reducing the risk of a further decrease in the etching solution concentration in the etching tank 10.

[0043] In some embodiments of the present invention, such as Figure 1 As shown, the water inlet unit 20 also includes a flow detection element 23, which is located in the water inlet pipe 21 and is used to detect the flow information of deionized water in the water inlet pipe 21. The control unit 50 is communicatively connected to the flow detection element 23 and is configured to control the first control valve 22 to close according to the deionized water flow information.

[0044] The flow detection element 23 can be a digital flow meter. The flow detection element 23 is installed in the water inlet pipe 21. The flow detection element 23 is used to detect the deionized water flow information in the water inlet pipe 21 in real time. The control unit 50 is communicatively connected to the flow detection element 23. The control unit 50 can be communicatively connected to the flow detection element 23 by wired or wireless means. When the concentration of the etching solution detected by the concentration detection structure 40 is greater than the preset concentration, the control unit 50 controls the first control valve 22 to open, and the deionized water in the water supply device flows into the etching tank 10 along the water inlet pipe 21. At the same time, the flow detection element 23 records the flow rate of the deionized water flowing through the water inlet pipe 21 in real time and uploads it to the control unit 50. When a certain amount of deionized water is introduced into the etching tank 10, in other words, when the flow detection element 23 detects that the flow rate of the deionized water flowing through the water inlet pipe 21 reaches the target, the control unit 50 controls the first control valve 22 to close, thereby achieving the effect of controlling the water inlet unit 20 to introduce a certain amount of deionized water into the etching tank 10, and accurately controlling the amount of deionized water entering the etching tank 10.

[0045] In some embodiments of the present invention, such as Figure 1 As shown, along the flow direction of deionized water in the inlet pipe 21, the flow detection element 23 is located upstream of the first control valve 22.

[0046] If the flow detection element 23 is located downstream of the first control valve 22, when the flow detection element 23 detects that the flow rate of deionized water flowing through the inlet pipe 21 has reached the target, deionized water will remain in the pipeline between the flow detection element 23 and the first control valve 22. After the control unit 50 controls the first control valve 22 to close, the deionized water remaining in the pipeline between the flow detection element 23 and the first control valve 22 will also flow into the etching tank 10, causing the amount of deionized water flowing into the etching tank 10 to be greater than the actual demand, which may easily lead to the etching solution concentration in the etching tank 10 being too low. Therefore, by setting the flow detection element 23 upstream of the first control valve 22, the risk of the amount of deionized water flowing into the etching tank 10 being greater than the actual demand is reduced, which is conducive to accurately controlling the amount of deionized water entering the etching tank 10, thereby helping to adjust the etching solution concentration in the etching tank 10 to a suitable concentration.

[0047] In some embodiments of the present invention, the control unit 50 is further configured to control the etching solution injection unit 30 to inject a fixed amount of etching solution into the etching tank 10 according to the etching solution concentration information.

[0048] The control unit 50 stores a control algorithm. When the etching solution concentration detected by the concentration detection structure 40 is less than the preset concentration, the control unit 50 obtains the etching solution concentration detected by the concentration detection structure 40. The control unit 50 calculates the amount of high-concentration etching solution that needs to be added to the etching tank 10 at this time through the control algorithm. Then, the control unit 50 controls the etching solution injection unit 30 to inject a fixed amount of high-concentration etching solution into the etching tank 10, adjusting the etching solution concentration in the etching tank 10 to a suitable concentration. This setting can accurately add the amount of high-concentration etching solution to the etching tank 10 according to the etching solution concentration information detected by the concentration detection structure 40, reducing the risk of adding too much or too little high-concentration etching solution to the etching tank 10, and accurately adjusting the etching solution concentration in the etching tank 10 to a suitable concentration.

[0049] As an example, after the second solenoid valve is opened, the etching solution injection unit 30 adds a certain amount of etching solution to the etching tank 10 per unit time. The control unit 50 calculates the required opening time of the second solenoid valve through the control algorithm based on the etching solution concentration information detected by the concentration detection structure 40. By controlling the opening time of the second solenoid valve through the control unit 50, the effect of controlling the etching solution injection unit 30 to add a fixed amount of high-concentration etching solution to the etching tank 10 is achieved.

[0050] In some embodiments of the present invention, such as Figure 1 As shown, the etching solution injection unit 30 includes: a storage container 31 and a second control valve 32. The storage container 31 is used to store etching solution. The second control valve 32 is located on the communication path between the storage container 31 and the etching tank 10 and is communicatively connected to the control unit 50. The control unit 50 controls the opening and closing of the storage container 31 and the etching tank 10 through the second control valve 32.

[0051] The storage container 31 is used to store high-concentration etching solution. The storage container 31 can store the high-concentration etching solution required for the etching tank 10 from the factory, ensuring that the high-concentration etching solution can be injected into the etching tank 10 in a timely manner during concentration adjustments. The etching solution concentration stored in the storage container 31 is higher than that in the etching tank 10. A connecting pipe can be connected between the storage container 31 and the etching tank 10, serving as a communication path between them. A second control valve 32 (i.e., the second solenoid valve in the above embodiment) is located in the connecting pipe. When the second control valve 32 is open, it connects the storage container 31 and the etching tank 10, allowing the etching solution in the storage container 31 to flow into the etching tank 10. When the second control valve 32 is closed, it de-connects the connecting pipe, preventing the connection between the storage container 31 and the etching tank 10, and allowing the etching solution in the storage container 31 to flow into the etching tank 10.

[0052] The second control valve 32 is communicatively connected to the control unit 50. When the etching solution concentration detected by the concentration detection structure 40 is less than the preset concentration, the control unit 50 controls the second control valve 32 to open, adding the etching solution from the storage container 31 into the etching tank 10, thus adjusting the etching solution concentration in the etching tank 10 to a suitable level. When the etching solution concentration detected by the concentration detection structure 40 is greater than the preset concentration, the control unit 50 controls the second control valve 32 to close, preventing the addition of etching solution from the storage container 31 into the etching tank 10 and reducing the risk of the etching solution concentration in the etching tank 10 continuing to rise.

[0053] In some embodiments of the present invention, such as Figure 1 As shown, the etching solution injection unit 30 also includes a drive pump 33, which is located on the communication path between the storage container 31 and the etching tank 10 and is communicatively connected to the control unit 50. The control unit 50 can control the drive pump 33 to be turned on or off.

[0054] The aforementioned connecting pipe can be the connecting path between the storage container 31 and the etching tank 10. The drive pump 33 can be installed in the connecting pipe and is communicatively connected to the control unit 50. The drive pump 33 can be communicatively connected to the control unit 50 via wired or wireless means.

[0055] When the etching solution concentration detected by the concentration detection structure 40 is less than the preset concentration, the control unit 50 controls the second control valve 32 to open. At the same time, the control unit 50 controls the drive pump 33 to start working. The drive pump 33 pumps the etching solution in the storage container 31 into the etching tank 10. When a certain amount of etching solution is added into the etching tank 10, the control unit 50 controls the second control valve 32 to close and controls the drive pump 33 to close, thereby achieving the effect of controlling the amount of high-concentration etching solution added into the etching tank 10 and accurately controlling the amount of high-concentration etching solution entering the etching tank 10.

[0056] In some embodiments of the present invention, such as Figure 1 As shown, the etching fluid injection unit 30 also includes: an etching fluid inlet pipe 34, the inlet of which is connected to the storage container 31, and the outlet of which is connected to the etching tank 10. The second control valve 32 and the drive pump 33 are both located in the etching fluid inlet pipe 34.

[0057] In this embodiment, the etching fluid inlet pipe 34 is the connecting pipe. The inlet of the etching fluid inlet pipe 34 is connected to the storage container 31, and the outlet of the etching fluid inlet pipe 34 (i.e., the second outlet in the above embodiment) is connected to the etching tank 10. The second control valve 32 and the drive pump 33 are both located in the etching fluid inlet pipe 34, connected in series. Along the flow direction of the etching fluid in the etching fluid inlet pipe 34, the drive pump 33 is located downstream of the second control valve 32. By setting the second control valve 32 and the drive pump 33 in the etching fluid inlet pipe 34, the etching fluid injection unit 30 can selectively inject etching fluid into the etching tank 10, and can also inject a quantitative amount of etching fluid into the etching tank 10, thus precisely controlling the amount of high-concentration etching fluid entering the etching tank 10.

[0058] In some embodiments of the present invention, such as Figure 1 As shown, the drive pump 33 is a fixed displacement pump.

[0059] Among them, the metering pump (also known as a quantitative pump or proportional pump) is a reciprocating positive displacement pump. Its core advantage lies in its ability to precisely control the liquid delivery rate, making it suitable for industrial scenarios requiring high-precision metering. Metering pumps have a low leakage rate, effectively preventing leaks of hazardous or corrosive liquids, thus improving the safety of the wet etching apparatus 100. Furthermore, metering pumps are simple in structure, low in cost, and easy to maintain.

[0060] The following details the data on the etching of the workpiece by the wet etching apparatus 100 of this application and the comparative data.

[0061] In this embodiment, three 6-inch Si wafers with the same pre-processing are used to continuously etch in batches within an etching tank 10. The etching solution concentration in the etching tank 10 is 30%, the process temperature is 60°C, and the etching time is 30 minutes. The wet etching apparatus 100 of this invention is used to control the etching solution concentration within the etching tank 10. The etching rates of the three 6-inch Si wafers are 20.56 μm / h, 20.62 μm / h, and 20.66 μm / h, respectively.

[0062] Comparative Example: Three 6-inch Si wafers with the same pre-processing were continuously etched in batches within an etching tank 10. The etching solution concentration in the etching tank 10 was 30%, the process temperature was 60°C, and the etching time was 30 minutes. Etching was performed in the etching tank 10, excluding the wet etching apparatus 100 of this application. The etching rates of the three 6-inch Si wafers were 20.40 μm / h, 20.51 μm / h, and 20.29 μm / h, respectively.

[0063] As can be seen from the above data, the inter-wafer uniformity among the three Si wafers in this embodiment is 0.24%, while the inter-wafer uniformity among the three Si wafers in the comparative example is 0.54%. Comparing the embodiments of this application with the comparative example, it can be found that the wet etching apparatus 100 of this application, used in the embodiments of this application to etch the workpiece, can control the concentration of the etching solution in the etching tank 10 within a precise range. Under continuous process conditions, Si wafers with better etching uniformity can be obtained. In mass continuous process production, the effect of controlling the concentration of etching solution in the etching tank 10 of the wet etching apparatus 100 of this application will be even more obvious.

[0064] It should be noted that the etching solution can be HF, KOH, etc. The wet etching apparatus 100 of this application features real-time performance, automation, and precision, meeting the high standards required for etching solution concentration in the etching process. It significantly reduces defects such as uneven etching rate, over-etching, and under-etching caused by fluctuations in etching solution concentration, thereby improving the electrical performance and reliability of the workpiece. The wet etching apparatus 100 of this application achieves dynamic control of the etching solution concentration within the etching tank 10, meeting the needs of continuous production.

[0065] Other configurations and operations of the wet etching apparatus 100 according to embodiments of the present invention are known to those skilled in the art and will not be described in detail here.

[0066] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0067] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A wet etching apparatus, characterized in that, include: An etching tank is used to hold etching solution and to place the workpiece to be etched. A water inlet unit is connected to the etching tank and is used to connect to a water supply device. The water inlet unit selectively introduces deionized water from the water supply device into the etching tank. An etching solution injection unit is connected to the etching tank, and the etching solution injection unit selectively injects etching solution into the etching tank; A concentration detection structure is provided inside the etching tank, and the concentration detection structure is used to detect the concentration information of the etching solution in the etching tank; The control unit is communicatively connected to the concentration detection structure, the water inlet unit, and the etching solution injection unit. The control unit is configured to control the working state of the water inlet unit and the working state of the etching solution injection unit according to the etching solution concentration information.

2. The wet etching apparatus according to claim 1, characterized in that, The control unit is also configured to control the water inlet unit to introduce a fixed amount of deionized water into the etching tank based on the etching solution concentration information.

3. The wet etching apparatus according to claim 1 or 2, characterized in that, The water inlet unit includes: a water inlet pipe and a first control valve. The water inlet of the water inlet pipe is connected to the water supply device, and the water outlet of the water inlet pipe is connected to the etching groove. The first control valve is located on the water inlet pipe and is communicatively connected to the control unit. The control unit controls the opening and closing of the water inlet and the water outlet through the first control valve.

4. The wet etching apparatus according to claim 3, characterized in that, The water inlet unit further includes a flow detection element, which is disposed in the water inlet pipe and used to detect the flow rate information of deionized water in the water inlet pipe. The control unit is communicatively connected to the flow detection element and is configured to control the first control valve to close according to the deionized water flow rate information.

5. The wet etching apparatus according to claim 4, characterized in that, Along the flow direction of deionized water in the inlet pipe, the flow detection element is located upstream of the first control valve.

6. The wet etching apparatus according to claim 1 or 2, characterized in that, The control unit is further configured to control the etching solution injection unit to inject a fixed amount of etching solution into the etching tank based on the etching solution concentration information.

7. The wet etching apparatus according to claim 6, characterized in that, The etching solution injection unit includes a storage container and a second control valve. The storage container is used to store etching solution. The second control valve is located on the communication path between the storage container and the etching tank and is communicatively connected to the control unit. The control unit controls the on / off state of the storage container and the etching tank through the second control valve.

8. The wet etching apparatus according to claim 7, characterized in that, The etching solution injection unit further includes a drive pump, which is located on the communication path between the storage container and the etching tank and is communicatively connected to the control unit. The control unit can control the drive pump to be turned on or off.

9. The wet etching apparatus according to claim 8, characterized in that, The etching fluid injection unit further includes: an etching fluid inlet pipe, the inlet of which is connected to the storage container, and the outlet of which is connected to the etching tank. The second control valve and the drive pump are both located in the etching fluid inlet pipe.

10. The wet etching apparatus according to claim 8, characterized in that, The driving pump is a metering pump.

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