Electroplating solution backflow control system and control method

Abstract

An electroplating solution backflow control system, comprising a process chamber, a solution storage tank, a control device, an overflow pipeline, a backflow pipeline, and a bubble detection device and a backflow control valve which are arranged on the backflow pipeline. The process chamber comprises a reaction tank and an overflow tank; an overflow port is formed at a preset height of the side wall of the overflow tank, and the overflow pipeline is used for communicating the overflow port with the solution storage tank; a backflow port is formed in the overflow tank, and the bubble detection device is arranged between the backflow port and the backflow control valve and used for detecting whether there are bubbles in an electroplating solution flowing through the bubble detection device in the backflow pipeline; and the control device is used for adjusting the opening degree of the backflow control valve on the basis of the detection result of the bubble detection device and the flow of the electroplating solution in the overflow pipeline, so as to adjust the flow of the backflow pipeline. The electroplating solution backflow control system can reduce or even eliminate the bubbles generated in the process of the electroplating solution flowing back to the solution storage tank from the electroplating process chamber, improve the stability of the electroplating solution, and thus improve the efficiency and stability of an electroplating process.

Description

Electroplating solution reflux control system and control method Technical Field

[0001] The present application relates to the field of semiconductor manufacturing equipment, and in particular to a plating solution reflux control system and control method. Background Art

[0002] In the electroplating process, the stability of the plating solution is crucial to the effectiveness of the plating process, directly affecting the quality and uniformity of the coating. Controlling bubbles in the plating solution is a key factor affecting the stability of the plating solution and the plating process. If bubbles are mixed into the plating solution, on the one hand, because the bubbles contain oxygen, they may oxidize and decompose the additives in the plating solution, causing the plating solution to become unstable and affecting the plating rate. On the other hand, bubbles enter the plating process chamber through the plating solution circulation system. During horizontal plating on the wafer, the locations where the bubbles come into contact will form cavities that hinder metal deposition, making it difficult to effectively electroplate the areas on the wafer where bubbles are present.

[0003] During the electroplating process, the plating solution is easily introduced with air and generates bubbles as it flows back from the plating process chamber to the liquid reservoir. Therefore, it is necessary to design a plating solution reflux control system and control method to effectively reduce or even eliminate bubbles generated during the process, thereby improving the stability of the plating solution and, consequently, the efficiency and stability of the electroplating process. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the object of the present invention is to provide a plating liquid reflux control system and control method, which is used to solve the problem that in the electroplating process of the prior art, bubbles are easily introduced when the plating liquid flows back from the electroplating process chamber to the liquid storage tank, resulting in low efficiency and process stability of the electroplating process.

[0005] To achieve the above-mentioned purpose and other related purposes, one aspect of the present invention provides a plating solution reflux control system, comprising a process chamber, a liquid storage tank, a control device, an overflow pipeline, a reflux pipeline, and a bubble detection device and a reflux control valve arranged on the reflux pipeline; wherein the process chamber comprises a reaction tank and an overflow tank, the overflow tank being arranged at the periphery of the reaction tank for receiving the plating solution overflowing from the reaction tank; an overflow port is provided at a predetermined height on the side wall of the overflow tank, the overflow pipeline being used to connect the overflow port and the liquid storage tank; the overflow tank is provided with a return valve. The reflux port is used to connect the reflux port and the liquid storage tank to return the electroplating liquid in the overflow tank to the liquid storage tank; the bubble detection device is arranged between the reflux port and the reflux control valve, and is used to detect whether there are bubbles in the electroplating liquid flowing through the bubble detection device in the reflux port; the control device is communicated with the reflux control valve and the bubble detection device, and is used to adjust the opening of the reflux control valve according to the detection result of the bubble detection device and the flow rate of the electroplating liquid in the overflow port, thereby adjusting the flow rate of the reflux port.

[0006] Another aspect of the present invention also provides a plating liquid reflux control method, comprising the following steps: S1, the process chamber starts to execute the process, the plating liquid overflows from the reaction tank to the overflow tank, and then flows into the liquid storage tank through the reflux pipe, so that the plating liquid circulates in the system; S2, a bubble detection device detects whether there are bubbles in the plating liquid flowing through the bubble detection device, and sends the detection result to the control device; S3, if the detection result is that there are bubbles, the control device reduces the opening of the reflux control valve and returns to step S2; if the detection result is that there are no bubbles, step S4 is executed after a first preset time; S4, adjusts the opening of the reflux control valve, and calculates the flow rate of the plating liquid in the overflow pipe until the flow rate of the plating liquid in the overflow pipe is no greater than the upper limit of the preset overflow flow rate range or until the flow rate in the overflow pipe is within the preset overflow flow rate range.

[0007] As described above, the present invention provides a plating liquid reflux control system and control method, wherein an overflow port is provided at a predetermined height on the side wall of an overflow tank, and an overflow pipe is used to connect the overflow port and a liquid storage tank; the overflow tank is provided with a reflux port, and a bubble detection device is provided between the reflux port and a reflux control valve, and is used to detect whether there are bubbles in the plating liquid flowing through the bubble detection device in the reflux pipe; the control device is used to adjust the opening of the reflux control valve according to the detection result of the bubble detection device and the flow rate of the plating liquid in the overflow pipe, thereby adjusting the flow rate of the reflux pipe, which can reduce or even eliminate bubbles generated in the process of the plating liquid flowing back from the electroplating process chamber to the liquid storage tank, improve the stability of the plating liquid, and thereby improve the efficiency and stability of the electroplating process.

[0008] Summary of the Figures

[0009] The features and performance of the present application are further described by the following examples and drawings.

[0010] FIG1 is a schematic diagram showing a plating solution reflux control system;

[0011] 2 and 3 are schematic diagrams showing a plating solution reflux control system according to a first embodiment of the present invention; and

[0012] FIG. 4 is a schematic flow chart showing a method for controlling electroplating solution reflux according to the present invention.

[0013] Preferred embodiment of this application

[0014] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details of this disclosure may be modified or altered based on different perspectives and applications without departing from the spirit of the present invention.

[0015] It should be noted that the drawings disclosed herein only illustrate the basic concept of the present invention in a schematic manner. Although the drawings only show components related to the present invention and are not drawn according to the number, shape and size of components in actual implementation, the form, quantity and proportion of each component in actual implementation may be changed at will, and the component layout may also be more complicated.

[0016] In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of devices consistent with some aspects of the present invention as detailed in the appended claims.

[0017] The terms used in this disclosure are for the purpose of describing specific embodiments only and are not intended to limit the disclosure. As used in this disclosure and the appended claims, the singular forms "a," "an," "the," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0018] In the description of the present disclosure, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection between two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

[0019] It should be understood that although the terms first, second, third, etc. may be used in the present disclosure to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other.

[0020] In the description of the present disclosure, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" that may be used to indicate orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting the present invention.

[0021] As shown in Figure 1, it is a schematic diagram of a plating liquid reflux control system. The system includes a process chamber 10, a reflux pipeline 20, and a liquid reservoir 30. The process chamber 10 is located at the top, and the liquid reservoir 30 is located at the bottom. The upper end of the reflux pipeline 20 is connected to the process chamber 10, and the lower end of the reflux pipeline 20 is connected to the liquid reservoir 30. It should be understood that in the wafer manufacturing process, multi-chamber electroplating equipment is usually used to improve production capacity. Figure 1 only shows one electroplating process chamber 10 in the electroplating equipment. The process chamber 10 includes a reaction tank 110 and an overflow tank 120 located outside the reaction tank 110. The plating liquid 130 is supplied from the liquid reservoir 30 to the reaction tank 110, and then overflows from the reaction tank 110 to the overflow tank 120. A reflux port is provided at the bottom of the overflow tank 120 so that the plating liquid 130 can flow back to the liquid reservoir 30 through the reflux pipeline 20.

[0022] To provide a buffer for the plating solution 130 in the reflux line 20, a collecting funnel 200 is typically provided on the reflux line 20. The collecting funnel 200 includes a collecting pipe 2001 at its top and a drain port located on its sidewall or bottom. The collecting pipe 2001 is connected to the reflux port of the overflow tank 120, and the drain port is connected to the main pipe body 201 of the reflux line 20. The upper end of the main pipe body 201 is connected to the drain port of the collecting funnel 200, and the lower end of the main pipe body 201 is connected to the liquid reservoir 30. The plating solution 130 in the overflow tank 120 first flows into the collecting funnel 200, and then flows from the collecting funnel 200 through the main pipe body 201 to the liquid reservoir 30. Because the overflow tank 120 is an open tank, as shown in Figure 1, when the amount of plating solution 130 in the overflow tank 120 is too low, air 40 will mix in, forming a large number of bubbles. The bubbles will flow into the liquid storage tank 30 along the reflux line 20 and circulate into the process chamber 10 along with the electroplating solution, affecting the stability of the electroplating solution 130 and further affecting the process efficiency and stability.

[0023] Example 1

[0024] To at least address the aforementioned issues, one aspect of the present invention provides a plating solution reflux control system. Referring to Figure 2 , a schematic diagram of the plating solution reflux control system according to a first embodiment of the present invention is shown. The plating solution reflux control system includes a process chamber 1, a liquid reservoir 3, a control device 231, an overflow line 4, a reflux line 2, and a bubble detection device 24 and a reflux control valve 23 disposed on the reflux line 2.

[0025] Illustratively, in this embodiment, the control device 231 can be a computer, PLC or other control device, the reflux control valve 23 can be a ball valve, and the bubble detection device 24 can be a dielectric constant bubble sensor, an optical bubble sensor, an ultrasonic bubble sensor or other device.

[0026] The process chamber 1 includes a reaction tank 11 and an overflow tank 12. The overflow tank 12 is disposed on the periphery of the reaction tank 11 and is used to receive the electroplating solution 13 overflowing from the reaction tank 11. The overflow tank 12 is provided with a reflux port 122. The reflux line 2 is used to connect the reflux port 122 and the liquid storage tank 3 to return the electroplating solution 13 in the overflow tank 12 to the liquid storage tank 3. As shown in Figure 2, in this embodiment, the reflux port 122 is disposed at the bottom of the overflow tank 12.

[0027] The bubble detection device 24 is arranged between the reflux port 122 and the reflux control valve 23, and is used to detect whether there are bubbles in the electroplating liquid 13 flowing through the bubble detection device 24 in the reflux pipeline 2; the control device 231 is communicated with the reflux control valve 23 and the bubble detection device 24, and is used to adjust the opening of the reflux control valve 23 according to the detection results of the bubble detection device 24 and the flow rate of the electroplating liquid 13 in the overflow pipeline 4, thereby adjusting the flow rate of the reflux pipeline 2.

[0028] Specifically, in this embodiment, the control device 231 is used to: store a preset overflow flow range, and when the bubble detection device 24 detects that there are bubbles, reduce the opening of the reflux control valve 23; when the bubble detection device 24 detects that there are no bubbles, after a first preset time period, adjust the opening of the reflux control valve 23, calculate the flow of the electroplating liquid 13 in the overflow pipe 4, and compare the flow of the electroplating liquid 13 in the overflow pipe 4 with the preset overflow flow until the flow of the electroplating liquid 13 in the overflow pipe 4 is no more than the upper limit of the preset overflow flow range or until the flow of the electroplating liquid 13 in the overflow pipe 4 is within the preset overflow flow range.

[0029] As shown in FIG2 , the bubble detection device 24 is disposed below and near the reflux port 122. If the bubble detection device 24 detects the presence of bubbles, it indicates that gas, such as air, has been mixed into the electroplating solution 13 in the overflow tank 12, and that the air has entered the reflux pipe 2 from the reflux port 122. The bubble detection device 24 sends the detection result to the control device 231, which reduces the opening of the reflux control valve 23, thereby reducing the flow rate of the reflux pipe 2. The electroplating solution 13 overflowing from the reaction tank 11 can accumulate in the overflow tank 12, thereby providing a liquid seal for the overflow tank 12 and preventing air from mixing into the electroplating solution 13 in the overflow tank 12 and entering the reflux pipe 2 from the reflux port 122.

[0030] After reducing the opening of the reflux control valve 23, the plating solution 13 may continue to accumulate in the overflow tank 12 and eventually overflow the process chamber 1 from the top of the overflow tank 12, causing pollution and waste, posing a safety risk, and preventing the process from continuing normally. Therefore, while ensuring that the plating solution 13 can accumulate in the overflow tank 12 to provide a liquid seal for the overflow tank 12, it is also necessary to prevent the plating solution 13 from accumulating too much in the overflow tank 12, which may affect the normal operation of the process.

[0031] To prevent the plating solution 13 from overflowing from the top of the overflow tank 12 and affecting the normal process, an overflow port 124 is provided at a predetermined height on the sidewall of the overflow tank 12, as shown in FIG2 . An overflow pipe 4 is used to connect the overflow port 124 and the liquid storage tank 3. When the plating solution 13 in the overflow tank 12 is excessive, it can flow into the liquid storage tank 3 through the overflow port 124 to prevent the plating solution 13 in the overflow tank 12 from overflowing from the process chamber 1.

[0032] After in-depth research and multiple experiments, the inventors found that when the flow rate of the plating liquid 13 in the overflow pipe 4 is maintained within a certain range, for example, 0-2 L / min, there can be sufficient plating liquid 13 in the overflow tank 12 to liquid-seal the overflow tank 12, and the risk of excessive plating liquid 13 in the overflow tank 12 overflowing from the top of the overflow tank 12 and overflowing the process chamber 1 can be reduced or even eliminated.

[0033] Specifically, a preset overflow flow rate, for example, 0-2 L / min, can be pre-set. The control device 231 then adjusts the opening of the reflux control valve 23 and calculates the corresponding flow rate of the plating solution 13 in the overflow pipe 4 until the bubble detection device 24 detects that there are no bubbles and the flow rate of the plating solution 13 in the overflow pipe 4 is no greater than the upper limit of the preset overflow flow rate range or is within the preset overflow flow rate range. The following is an exemplary operation of the plating solution reflux control system in this embodiment.

[0034] First, the process chamber 1 starts to execute the process, and the plating solution 13 overflows from the reaction tank 11 to the overflow tank 12, and then flows into the liquid storage tank 3 through the reflux pipe 2, so that the plating solution 13 circulates in the system;

[0035] Then, the bubble detection device 24 detects whether there are bubbles in the plating solution 13 flowing through the bubble detection device 24 and sends the detection result to the control device 231; if the detection result is that there are bubbles, the control device 231 reduces the opening of the reflux control valve 23 until the detection result is that there are no bubbles; if the detection result is that there are no bubbles, after a first preset time, the control device 231 adjusts the opening of the reflux control valve 23 and calculates the flow rate of the plating solution 13 in the overflow pipe 4 until the flow rate of the plating solution 13 in the overflow pipe 4 is within the preset overflow flow range. It should be understood that the first preset time is set to allow the plating solution 13 to continue to accumulate in the overflow tank 12 for a period of time to avoid the plating solution 13 from being reduced too quickly during subsequent adjustments, thereby causing air to mix into the reflux pipe 2. Those skilled in the art can set the first preset time according to actual conditions, and the first preset time can also be 0.

[0036] The following are exemplary steps for calculating the flow rate of the plating solution 13 in the overflow pipe 4:

[0037] First, the control device 231 increases the opening of the reflux control valve 23, and records the opening K1 and time T0 of the reflux control valve 23 when the increase is started; until the bubble detection device 24 detects that there are bubbles, the opening K2 and time T1 of the reflux control valve 23 at this time are recorded; the pre-stored flow rate F1 of the reflux pipeline 2 at the opening K1, the flow rate F2 of the reflux pipeline 2 at the opening K2, and the volume V in the overflow tank 12 from the overflow port 124 to the critical position where the bubble detection device 24 detects that there are bubbles are obtained. According to the equation F3 = (F2-F1)-V / (T1-T0), the flow rate F3 of the plating solution 13 in the overflow pipeline 4 at the opening K2 can be calculated.

[0038] It should be understood that there is a known mathematical relationship between the opening of the reflux control valve 23 and the liquid flow rate through the reflux control valve 23. In the equation F3 = (F2 - F1) - V / (T1 - T0), F1 is the flow rate in the reflux line 2 measured at the opening of K1, and F2 is the flow rate in the reflux line 2 measured at the opening of K2, i.e., F2 = f(K2) and F1 = f(K1). T1 and T0 are known quantities, and V is the volume of the plating solution 13 reduced in the overflow tank 12 from the time overflowing of the overflow line 4 begins to occur until the bubble detection device 24 detects the presence of bubbles. This is the volume V in the overflow tank 12 from the overflow port 124 to the critical position where the bubble detection device 24 detects the presence of bubbles. Given the location of the overflow port 124 and the dimensions of the overflow tank 12, V is also a known quantity that can be measured. Therefore, the flow rate F3 of the electroplating solution 13 in the overflow pipe 4 at this time can be calculated using the above equation.

[0039] If F3 is not greater than the upper limit of the preset overflow flow range, the control device 231 maintains the current opening of the reflux control valve 23; if F3 is greater than the upper limit of the preset overflow flow range, the control device 231 increases the opening of the reflux control valve 23, and calculates the flow in the overflow pipe 4 according to the above-mentioned exemplary steps of calculating the flow in the overflow pipe 4 until the flow of the electroplating solution 13 in the overflow pipe 4 is no greater than the upper limit of the preset overflow flow range.

[0040] Through the above steps, when the bubble detection device 24 detects that there are bubbles, the control device 231 reduces the opening of the reflux control valve 23 so that there is enough electroplating liquid 13 in the overflow tank 12 to liquid-seal the overflow tank 12, preventing air from mixing into the reflux pipe 2 through the overflow tank 12 and forming bubbles; when the bubble detection device 24 detects that there are no bubbles, after a first preset time, the control device 231 adjusts the opening of the reflux control valve 23 and calculates the flow rate of the electroplating liquid 13 in the overflow pipe 4 until the flow rate of the electroplating liquid 13 in the overflow pipe 4 is no more than the upper limit of the preset overflow flow rate range, thereby reducing or even eliminating the risk of excessive electroplating liquid 13 in the overflow tank 12 overflowing from the top of the overflow tank 12 out of the process chamber 1.

[0041] Alternatively, in other possible embodiments, after calculating the flow rate F3 of the plating solution 13 in the overflow pipe 4 under the opening K2, if F3 is within the preset overflow flow range, the control device 231 maintains the current opening of the reflux control valve 23; if F3 is greater than the upper limit of the preset overflow flow range, the control device 231 increases the opening of the reflux control valve 23, and calculates the flow rate in the overflow pipe 4 according to the exemplary steps of calculating the flow rate of the plating solution 13 in the overflow pipe 4, until the flow rate of the plating solution 13 in the overflow pipe 4 is within the preset overflow flow range; if F3 is less than the preset overflow flow, the control device 231 adjusts the opening of the reflux control valve 23 to a larger value. The lower limit of the range indicates that the plating solution 13 accumulated in the overflow tank 12 at this time is sufficient to seal the overflow tank 12, but the volume is less than the volume of the plating solution 13 when it reaches the overflow port 124. It may soon reach the critical position where the bubble detection device 24 detects the presence of bubbles. Therefore, the opening of the reflux control valve 23 can be first reduced and maintained for the second preset time period, and then the opening of the reflux control valve 23 can be increased. The flow rate in the overflow pipe 4 is calculated according to the exemplary steps for calculating the flow rate of the plating solution 13 in the overflow pipe 4 described above until the flow rate of the plating solution 13 in the overflow pipe 4 is within the preset overflow flow rate range. It should be understood that the lower limit of the preset overflow flow rate range in this example is 0, so the calculated value F3 may also be negative.

[0042] Optionally, the system can be updated regularly or irregularly, for example, after completing the electroplating of a batch of wafers, and the opening of the reflux control valve 23 can be re-determined according to the above steps until the bubble detection device 24 detects that there are no bubbles and the flow rate of the plating liquid 13 in the overflow pipe 4 is not greater than the upper limit of the preset overflow flow rate range or is within the preset overflow flow rate range, so as to improve the reliability of the plating liquid reflux control system.

[0043] Optionally, before executing the process in the process chamber 1, a more appropriate initial opening K of the reflux control valve 23 can be obtained by simulating the process and referring to the steps of executing the process in the process chamber 1, so that the flow rate of the plating liquid 13 in the overflow pipe 4 is maintained within a certain range, for example, 0-2L / min. This can ensure that there is sufficient plating liquid 13 in the overflow tank 12 to liquid-seal the overflow tank 12, and can also reduce or even eliminate the risk of excessive plating liquid 13 in the overflow tank 12 overflowing from the top of the overflow tank 12 and out of the process chamber 1. In this way, when executing the process, the reflux control valve 23 can be directly adjusted to the initial opening K, and then the system can be automatically adjusted based on the initial opening K, which can effectively improve the efficiency of the system's automatic adjustment.

[0044] Here are some exemplary steps:

[0045] The opening of the reflux control valve 23 is adjusted to a relatively large initial value, for example, 100%, to allow the plating solution 13 to begin circulating in the system. The bubble detector 24 then detects whether there are bubbles in the plating solution 13 flowing through it. At this point, the plating solution 13 in the overflow tank 12 has not yet accumulated, and a large amount of air enters the reflux line 2 along with the plating solution 13. The bubble detector 24 detects the presence of bubbles.

[0046] The opening of the reflux control valve 23 is gradually reduced to allow the plating solution 13 to accumulate in the overflow trough 12 until the plating solution 13 overflows the overflow pipe 4 through the overflow port 124. The time T00 and the opening K01 of the reflux control valve 23 are recorded. It should be understood that the location of the overflow port 124 can be appropriately designed based on the actual structure of the overflow trough 12 to ensure safe system operation. When the plating solution 13 exceeds the overflow port 124, there is a safety risk of the plating solution 13 overflowing from the top of the overflow trough 12 and out of the process chamber 1.

[0047] Gradually increase the opening of the reflux control valve 23 to gradually reduce the plating solution 13 in the overflow tank 12 until the bubble detection device 24 detects bubbles again. Record the time at this time as T01 and the opening of the reflux control valve 23 as K02.

[0048] It should be understood that K01 and K02 can be empirical values ​​that are easily known to those skilled in the art, for example, K01 is 55% and K02 is 60%. There is a known mathematical relationship between the opening of the reflux control valve 23 and the liquid flow through the reflux control valve 23. When K01 is opened, the flow F01 of the reflux line 2 can be calculated, and when K02 is opened, the flow F02 of the reflux line 2 can be calculated, that is, F01 = f(K01) and F02 = f(K02).

[0049] The flow rate F03 of the electroplating solution 13 in the overflow pipe 4 at this time can be calculated by the following equation (1):

[0050] (1)F03=(F02-F01)-V / (T01-T00).

[0051] Among them, F01 is the flow rate of the return pipe 2 measured under the opening of K01, and F02 is the flow rate of the return pipe 2 measured under the opening of K02. F01=f(K01), F02=f(K02), the opening values ​​of K01 and K02 are known empirical values, so F01 and F02 are also known quantities that can be measured; T01 and T00 are known quantities, V is the volume of the electroplating solution 13 reduced in the overflow tank 12 during the time period from T00 when the overflow pipe 4 begins to overflow to T01 when the bubble detection device 24 detects bubbles, that is, the volume V in the overflow tank 12 from the overflow port 124 to the critical position where the bubble detection device 24 detects bubbles. When the position of the overflow port 124 and the size of the overflow tank 12 are known, V is also a known quantity that can be measured. Therefore, the flow rate F03 of the electroplating solution 13 in the overflow pipe 4 at this time can be calculated through the above equation.

[0052] If F03 is within the preset overflow flow range, for example, 0≤F03≤2L / min, then the opening K02 is appropriate.

[0053] If F03 is greater than the preset overflow flow range, for example, F03>2L / min, it means that the opening of the reflux control valve 23 needs to be increased, that is, the value of K02 needs to be increased;

[0054] If F03 is smaller than the preset overflow flow range, for example, F03<0 L / min, it means that the opening of the reflux control valve 23 needs to be reduced, that is, the value of K02 needs to be reduced.

[0055] Repeat the above steps to obtain the appropriate opening K02, so that 0≤F03≤2L / min, and store the opening K02 at this time as the initial opening K. In this way, when executing the process, the reflux control valve 23 can be directly adjusted to the initial opening K, and then the system can be automatically adjusted based on the initial opening K, which can effectively improve the efficiency of the system's automatic adjustment.

[0056] Optionally, at least for the purpose of providing a certain buffer for the electroplating solution 13 in the return line 2, the return line 2 includes a liquid collecting funnel 21 and a pipeline body 22. As shown in FIG2 , the liquid collecting funnel 21 illustratively includes a liquid collecting pipe 211 at its top and a liquid drain port at its bottom. The liquid collecting pipe 211 is connected to the return port 122, and the liquid drain port is connected to the pipeline body 22. In other possible embodiments, the liquid drain port may also be provided on the side wall.

[0057] As shown in FIG3 , in an electroplating device having multiple process chambers 1 , each liquid collecting funnel 21 may also have two liquid collecting pipes 211 . In this case, the liquid collecting funnel 21 connects two process chambers 1 , becoming a common reflux area in the reflux control system of the two process chambers 1 .

[0058] Optionally, since the process environment is typically acidic or alkaline, which is a relatively harsh environment, to increase the reliability of system control, in this embodiment, as shown in FIG2 , the bubble detection device 24 includes a first bubble detection device 241 and a second bubble detection device 242. The second bubble detection device 242 is disposed between the first bubble detection device 241 and the reflux control valve 23. The reflux control valve 23 is configured to reduce the opening of the reflux line 2 when the first bubble detection device 241 and / or the second bubble detection device 242 detect the presence of bubbles. That is, as long as at least one of the first bubble detection device 241 and the second bubble detection device 242 detects the presence of bubbles, the reflux control valve 23 reduces the opening of the reflux line 2.

[0059] Example 2

[0060] 4 , another aspect of the present invention provides a plating solution reflux control method, which is applied to the plating solution reflux control system in Example 1, comprising:

[0061] S1, process chamber 1 starts to execute the process, the plating solution 13 overflows from the reaction tank 11 to the overflow tank 12, and then flows into the storage tank 3 through the reflux pipe 2, so that the plating solution 13 circulates in the system;

[0062] S2, the bubble detection device 24 detects whether there are bubbles in the plating solution 13 flowing through the bubble detection device 24, and sends the detection result to the control device 231;

[0063] S3, if the detection result shows that there are bubbles, the control device 231 reduces the opening of the reflux control valve 23 and returns to step S2; if the detection result shows that there are no bubbles, step S4 is executed after the first preset time period;

[0064] S4, adjust the opening of the reflux control valve 23, and calculate the flow rate of the electroplating solution 13 in the overflow pipe 4 until the flow rate of the electroplating solution 13 in the overflow pipe 4 is no more than the upper limit of the preset overflow flow rate range or until the flow rate of the electroplating solution 13 in the overflow pipe 4 is within the preset overflow flow rate range.

[0065] In this embodiment, step S4 further includes:

[0066] S41, the control device 231 increases the opening of the reflux control valve 23, and records the opening K1 of the reflux control valve 23 and the time T0 when the increase is started;

[0067] S42, until the bubble detection device 24 detects the presence of bubbles, the opening degree K2 of the reflux control valve 23 and the time T1 are recorded;

[0068] S43 , obtaining the pre-stored flow rate F1 of the return line 2 at the opening K1, the flow rate F2 of the return line 2 at the opening K2, and the volume V of the overflow tank 12 from the overflow port 124 to the critical position where bubbles are detected by the bubble detection device 24 , and calculating the flow rate of the electroplating solution 13 in the overflow line 4 at this time according to the equation F3 = (F2 - F1) - V / (T1 - T0);

[0069] S44, if F3 is not greater than the upper limit of the preset overflow flow range, the control device 231 maintains the current opening of the reflux control valve 23;

[0070] If F3 is greater than the upper limit of the preset overflow flow range, the process returns to step S41.

[0071] Optionally, before the process chamber 1 performs the process, a more appropriate initial opening K of the reflux control valve 23 can be obtained by simulating the process and referring to the steps of performing the process in the process chamber 1. For example, before step S1, the following steps are further included:

[0072] S01, adjusting the opening of the reflux control valve 23 to 100%, allowing the plating solution 13 to begin circulating in the system, and the bubble detection device 24 detects whether there are bubbles in the plating solution 13 flowing through it;

[0073] S02, gradually reduce the opening of the reflux control valve 23 so that the plating solution 13 can continue to accumulate in the overflow tank 12 until the plating solution 13 overflows in the overflow pipe 4 through the overflow port 124, and record the moment T00 at this time and the opening K01 of the reflux control valve 23; during this process, the detection result of the bubble detection device 24 can be from the presence of bubbles to the absence of bubbles.

[0074] S03, gradually increase the opening of the reflux control valve 23 to gradually reduce the amount of the electroplating solution 13 in the overflow tank 12 until the bubble detection device 24 detects bubbles again. The time at this point is recorded as T01, and the opening of the reflux control valve 23 is K01;

[0075] S04, the flow rate F03 of the electroplating solution 13 in the overflow pipe 4 at this time is calculated by equation (1):

[0076] (1)F03=(F02-F01)-V / (T01-T00);

[0077] Among them, F01 is the flow rate of the return pipe 2 measured under the opening of K01, F02 is the flow rate of the return pipe 2 measured under the opening of K02, F01=f(K01), F02=f(K02), the opening values ​​of K01 and K02 are known empirical values, therefore, F01 and F02 are also known quantities that can be measured; T01 and T00 are known quantities, V is the time from T00 when overflow begins to occur in the overflow pipe 4 to T01 when the bubble detection device 24 detects that there are bubbles, that is, the volume V in the overflow tank 12 from the overflow port 124 to the critical position where the bubble detection device 24 detects that there are bubbles. When the position of the overflow port 124 and the size of the overflow tank 12 are known, V is also a known quantity that can be measured.

[0078] S05, if F03 is not greater than the upper limit of the preset overflow flow range, the opening K02 at this time is stored as the initial opening K; if F03 is greater than the upper limit of the preset overflow flow range, repeat the above steps S01-S04.

[0079] In this way, when executing the process, the reflux control valve 23 can be directly adjusted to the initial opening K, and then the system can be automatically adjusted based on the initial opening K, which can effectively improve the efficiency of the system's automatic adjustment.

[0080] Optionally, in other possible embodiments, the step of obtaining a more appropriate initial opening K of the reflux control valve 23 may also be different from the above step. Another exemplary step is given below.

[0081] Specifically, before step S1, the method further includes:

[0082] S010, adjusting the opening of the reflux control valve 23 to 100%, allowing the plating solution 13 to begin circulating in the system, and the bubble detection device 24 detects whether there are bubbles in the plating solution 13 flowing through it;

[0083] S020, gradually reduce the opening of the reflux control valve 23 so that the plating solution 13 can continue to accumulate in the overflow tank 12 until the plating solution 13 overflows in the overflow pipe 4 through the overflow port 124, and record the moment T00 at this time and the opening K01 of the reflux control valve 23; during this process, the detection result of the bubble detection device 24 can be from bubbles to no bubbles.

[0084] S030, gradually increase the opening of the reflux control valve 23 to gradually reduce the amount of the electroplating solution 13 in the overflow tank 12 until the bubble detection device 24 detects bubbles again. Record this time as T01 and the opening of the reflux control valve 23 as K01;

[0085] S040, the flow rate F03 of the electroplating solution 13 in the overflow pipe 4 at this time is calculated by equation (1):

[0086] (1)F03=(F02-F01)-V / (T01-T00);

[0087] S050, if F03 is within the preset overflow flow range, the opening K02 at this time is stored as the initial opening K; if F03 is not within the preset overflow flow range, repeat the above steps S010-S040.

[0088] Among them, if F03 is greater than the preset overflow flow range, for example, F03>2L / min, it means that the opening of the reflux control valve 23 needs to be increased at this time; if F03 is less than the preset overflow flow range, for example, F03<0L / min, it means that the opening of the reflux control valve 23 needs to be reduced at this time.

[0089] Example 3

[0090] The third embodiment provides a plating solution reflux control method, which is applied to the plating solution reflux control system in the first embodiment. The main differences from the second embodiment are:

[0091] In step S4, further comprising:

[0092] S410, the control device 231 increases the opening of the reflux control valve 23 and records the opening K1 of the reflux control valve 23 and the time T0 when the increase is started;

[0093] S420, until the bubble detection device 24 detects the presence of bubbles, the opening degree K2 of the reflux control valve 23 and the time T1 are recorded;

[0094] At step S430 , the pre-stored flow rate F1 of the return line 2 at the opening K1, the flow rate F2 of the return line 2 at the opening K2, and the volume V of the overflow tank 12 from the overflow port 124 to the critical position where bubbles are detected by the bubble detection device 24 are obtained. The flow rate of the electroplating solution 13 in the overflow line 4 at this time is calculated according to the equation F3 = (F2 - F1) - V / (T1 - T0);

[0095] S440, if F3 is within the preset overflow flow range, the control device 231 maintains the current opening of the return control valve 23; if F3 is greater than the upper limit of the preset overflow flow range, return to step S410; if F3 is less than the lower limit of the preset overflow flow range, reduce the opening of the return control valve 23 and maintain it for the second preset time length, and then return to step S410.

[0096] If F3 is less than the lower limit of the preset overflow flow range, it means that the plating liquid 13 accumulated in the overflow tank 12 is sufficient to seal the overflow tank 12, but the volume is less than the volume when the plating liquid 13 reaches the overflow port 124. The critical position at which the bubble detection device 24 detects bubbles may be quickly reduced. Therefore, the opening of the reflux control valve 23 can be reduced and maintained for a second preset time, and then the opening of the reflux control valve 23 can be increased. The flow rate of the plating liquid 13 in the overflow pipe 4 is calculated according to the above-mentioned exemplary steps for calculating the flow rate of the plating liquid 13 in the overflow pipe 4 until the flow rate of the plating liquid 13 in the overflow pipe 4 is within the preset overflow flow rate range.

[0097] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A plating solution reflux control system, characterized in that: include: A process chamber, a liquid storage tank, a control device, an overflow pipeline, a reflux pipeline, and a bubble detection device and a reflux control valve arranged on the reflux pipeline; wherein, The process chamber comprises a reaction tank and an overflow tank, wherein the overflow tank is arranged at the periphery of the reaction tank and is used to receive the electroplating solution overflowing from the reaction tank; An overflow port is provided at a predetermined height on the side wall of the overflow tank, and the overflow pipeline is used to connect the overflow port and the liquid storage tank; The overflow tank is provided with a reflux port, and the reflux pipeline is used to connect the reflux port and the liquid storage tank to return the electroplating liquid in the overflow tank to the liquid storage tank; The bubble detection device is arranged between the reflux port and the reflux control valve, and is used to detect whether there are bubbles in the electroplating solution flowing through the bubble detection device in the reflux pipeline; The control device is communicatively connected with the reflux control valve and the bubble detection device, and is used to adjust the opening of the reflux control valve according to the detection result of the bubble detection device and the flow rate of the electroplating solution in the overflow pipeline, thereby adjusting the flow rate of the reflux pipeline.

2. The electroplating solution reflux control system according to claim 1, characterized in that: The control device is also used to: store a preset overflow flow range, and reduce the opening of the reflux control valve when the bubble detection device detects the presence of bubbles; when the bubble detection device detects the absence of bubbles, adjust the opening of the reflux control valve after a first preset time period, calculate the flow of the electroplating solution in the overflow pipeline, and compare the flow of the electroplating solution in the overflow pipeline with the preset overflow flow until the flow of the electroplating solution in the overflow pipeline is no more than the upper limit of the preset overflow flow range or until the flow in the overflow pipeline is within the preset overflow flow range.

3. The electroplating solution reflux control system according to claim 2, characterized in that: The control device is also used for: when the bubble detection device detects that there are no bubbles, after a first preset time period, increasing the opening of the reflux control valve, calculating the flow of the electroplating liquid in the overflow pipe, and comparing the flow of the electroplating liquid in the overflow pipe with the preset overflow flow; if the flow of the electroplating liquid in the overflow pipe is not greater than the upper limit of the preset overflow flow range, maintaining the current opening of the reflux control valve; if the flow of the electroplating liquid in the overflow pipe is greater than the upper limit of the preset overflow flow range, increasing the opening of the reflux control valve until the flow of the electroplating liquid in the overflow pipe is no greater than the upper limit of the preset overflow flow range.

4. The electroplating solution reflux control system according to claim 2, characterized in that: The control device is also used for: when the bubble detection device detects that there are no bubbles, after a first preset time, increasing the opening of the reflux control valve, calculating the flow of the electroplating solution in the overflow pipeline, comparing the flow of the electroplating solution in the overflow pipeline with the preset overflow flow, and if the flow of the electroplating solution in the overflow pipeline is within the preset overflow flow range, maintaining the current opening of the reflux control valve; if the flow of the electroplating solution in the overflow pipeline is greater than the upper limit of the preset overflow flow range, increasing the opening of the reflux control valve until the flow of the electroplating solution in the overflow pipeline is within the preset overflow flow range; if the flow of the electroplating solution in the overflow pipeline is less than the lower limit of the preset overflow flow range, reducing the opening of the reflux control valve and maintaining it for a second preset time, and then increasing the opening of the reflux control valve until the flow of the electroplating solution in the overflow pipeline is within the preset overflow flow range.

5. The electroplating solution reflux control system according to claim 1, characterized in that: The reflux pipeline comprises a liquid collecting funnel and a pipeline body. The liquid collecting funnel comprises a liquid collecting pipe and a liquid discharge port. The liquid collecting pipe is connected to the reflux port, and the liquid discharge port is connected to the pipeline body.

6. The electroplating solution reflux control system according to claim 1, characterized in that: The bubble detection device comprises a first bubble detection device and a second bubble detection device, The second bubble detection device is arranged between the first bubble detection device and the reflux control valve.

7. A plating solution reflux control method, applied to the plating solution reflux control system according to claim 1, characterized in that: include: S1, the process chamber starts to execute the process, the plating solution overflows from the reaction tank to the overflow tank, and then flows into the storage tank through the reflux pipeline, so that the plating solution circulates in the system; S2, the bubble detection device detects whether there are bubbles in the plating solution flowing through the bubble detection device, and sends the detection result to the control device; S3, if the detection result is that there are bubbles, the control device reduces the opening of the reflux control valve and returns to S2; if the detection result is that there are no bubbles, after a first preset time, S4 is executed; S4, adjusting the opening of the reflux control valve and calculating the flow rate of the electroplating solution in the overflow pipeline until the flow rate of the electroplating solution in the overflow pipeline is no greater than the upper limit of a preset overflow flow rate range or until the flow rate of the electroplating solution in the overflow pipeline is within the preset overflow flow rate range.

8. The electroplating solution reflux control method according to claim 7, characterized in that: S4 further includes: S41, the control device increases the opening of the reflux control valve, and records the opening K1 of the reflux control valve 23 and the time T0 when the increase begins; S42, until the bubble detection device detects that there are bubbles, record the opening degree K2 of the reflux control valve and the time T1 at this time; S43, obtaining the pre-stored flow rate F1 of the return line at the opening K1, the flow rate F2 of the return line at the opening K2, and the volume V in the overflow tank from the overflow port to the critical position where the bubble detection device detects bubbles, and calculating the flow rate of the electroplating solution in the overflow line at this time according to the equation F3 = (F2-F1)-V / (T1-T0); S44, if F3 is not greater than the upper limit of the preset overflow flow range, the control device maintains the current opening of the reflux control valve; if F3 is greater than the upper limit of the preset overflow flow range, return to S41.

9. The electroplating solution reflux control method according to claim 7, characterized in that: S4 further includes: S410, the control device increases the opening of the reflux control valve, and records the opening K1 of the reflux control valve and the time T0 when the increase begins; S420, until the bubble detection device detects that there are bubbles, record the opening degree K2 and time T1 of the reflux control valve at this time; S430, obtaining the pre-stored flow rate F1 of the return pipe at the opening K1, the flow rate F2 of the return pipe at the opening K2, and the volume V in the overflow tank from the overflow port to the critical position where the bubble detection device detects bubbles, and calculating the flow rate of the electroplating solution in the overflow pipe at this time according to the equation F3 = (F2-F1)-V / (T1-T0); S440, if F3 is within the preset overflow flow range, the control device maintains the current opening of the reflux control valve; if F3 is greater than the upper limit of the preset overflow flow range, it returns to S410; if F3 is less than the lower limit of the preset overflow flow range, the opening of the reflux control valve is reduced and maintained for the second preset time length, and then returns to S410.

10. The electroplating solution reflux control method according to claim 8 or 9, characterized in that: Prior to S1, it also included: S01, the plating solution overflows from the reaction tank to the overflow tank, and then flows into the storage tank through the reflux pipeline, so that the plating solution circulates in the system, and the opening of the reflux control valve is adjusted to 100%, and the bubble detection device detects whether there are bubbles in the plating solution flowing through itself; S02, gradually reduce the opening of the reflux control valve so that the plating solution can continue to accumulate in the overflow tank until the plating solution overflows in the overflow pipe through the overflow port, and record the time T00 and the opening K01 of the reflux control valve at this time; S03, gradually increase the opening of the reflux control valve to gradually reduce the amount of electroplating solution in the overflow tank until the bubble detection device detects bubbles again, and record the time at this time as T01, and the opening of the reflux control valve as K02; S04, the flow rate F03 of the electroplating solution in the overflow pipeline at this time is calculated by equation (1): (1)F03=(F02-F01)-V / (T01-T00); Among them, F01 is the flow rate of the return pipe measured at the opening of K01, and F02 is the flow rate of the return pipe measured at the opening of K02; V is the volume of the overflow tank from the overflow port to the critical position where the bubble detection device detects bubbles; S05, if F03 is not greater than the upper limit of the preset overflow flow range, the opening K02 at this time is stored as the initial opening K; if F03 is greater than the upper limit of the preset overflow flow range, S01-S04 are repeated.

11. The electroplating solution reflux control method according to claim 8 or 9, characterized in that: Prior to S1, it also included: S010, the plating solution overflows from the reaction tank to the overflow tank, and then flows into the storage tank through the reflux pipeline, so that the plating solution circulates in the system, and the opening of the reflux control valve is adjusted to 100%, and the bubble detection device detects whether there are bubbles in the plating solution flowing through itself; S020, gradually reduce the opening of the reflux control valve so that the plating solution can continue to accumulate in the overflow tank until the plating solution overflows in the overflow pipe through the overflow port, and record the time T00 and the opening K01 of the reflux control valve at this time; S030, gradually increase the opening of the reflux control valve to gradually reduce the amount of electroplating solution in the overflow tank until the bubble detection device detects bubbles again, and record the time at this time as T01, and the opening of the reflux control valve as K02; S040, the flow rate F03 of the electroplating solution in the overflow pipeline at this time is calculated by equation (1): (1)F03=(F02-F01)-V / (T01-T00); Among them, F01 is the flow rate of the return pipe measured at the opening of K01, and F02 is the flow rate of the return pipe measured at the opening of K02; V is the volume of the overflow tank from the overflow port to the critical position where the bubble detection device detects bubbles; S050, if F03 is within the preset overflow flow range, the opening degree K02 at this time is stored as the initial opening degree K; if F03 is not within the preset overflow flow range, S010-S040 are repeated.

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