Current stabilization system applied to simultaneous opening of multiple branches and control method thereof

Abstract

The invention discloses a flow stabilizing system applied to simultaneous opening of multiple branches and a control method of the flow stabilizing system in the field of wafer cleaning, and the system comprises a concentric-square-shaped circulation pipeline of a closed-loop structure, a plurality of process branches, a back pressure adjusting unit composed of an electric control proportional valve and a back pressure valve, and monitoring units distributed on the sides of water taking ends of the branches. The control unit adjusts the air inlet pressure of the back pressure valve through the electric control proportional valve according to a real-time pressure deviation signal obtained by the monitoring unit so as to change the backflow resistance of the liquid return port, so that when the multiple branches are opened at the same time to cause pressure drop, the energy of the liquid medicine is locked in the circulation pipeline, and dynamic compensation of the flow of each process branch is achieved. According to the invention, the physical energy storage characteristic of the homocentric-square-shaped pipeline and the active backpressure regulation logic are combined, the problem of flow fluctuation caused by multi-station random switching is effectively solved, and the uniformity and stability of the wafer cleaning process are ensured.

Description

Technical Field

[0001] This invention relates to the field of wafer cleaning, and more specifically to a current stabilization system and its control method for multiple branches operating simultaneously. Background Technology

[0002] In the field of semiconductor cleaning technology, in order to meet the high-precision cleaning process requirements of multiple chambers or multiple branches, the "one main pipe and multiple branches" solution supply mode is usually adopted, that is, deionized water or chemical solution is delivered to multiple process chambers through a common main solution supply pipeline.

[0003] Traditional liquid supply systems often adopt a tree topology, and the pressure of the main pipeline is usually set to a predetermined fixed value. However, in actual production, each process branch often needs to be opened or closed according to different process sequences, resulting in the flow rate of the branch being in a state of continuous fluctuation.

[0004] Especially when multiple process chambers are open at the same time, the surge in instantaneous flow demand leads to increased fluid kinetic energy loss in the main pipeline, often causing a significant drop in pressure in the main pipeline and at each water intake point. This pressure drop becomes more pronounced as the number of branch lines increases.

[0005] Such unstable pressure fluctuations will directly cause the actual flow rate entering each branch to deviate from the set standard, which in turn will cause process defects such as insufficient spray pressure, decreased cleaning uniformity and poor control of residues, seriously affecting the yield and consistency of the product. Summary of the Invention

[0006] The purpose of this invention is to provide a current stabilization system and its control method for multiple branches operating simultaneously, so as to solve the problems of main line pressure drop and flow fluctuation of each branch caused by the surge in instantaneous flow demand when multiple branches are opened at the same time.

[0007] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution: A current stabilization system for use with multiple branches operating simultaneously includes: A U-shaped circulation pipeline, which has one inlet and one outlet; There are multiple process branches, and each process branch has a water intake end connected to the U-shaped circulation pipeline; The back pressure regulating unit is located at the return port and includes a back pressure valve and an electrically controlled proportional valve connected to the execution control terminal of the back pressure valve. The electrically controlled proportional valve compensates for the pressure in the U-shaped circulation pipeline by adjusting the opening of the back pressure valve. The monitoring unit includes multiple branch pressure sensors installed on the U-shaped circulation pipeline. The number of branch pressure sensors matches the number of water intakes. Each branch pressure sensor is installed next to the corresponding water intake to monitor the pipeline pressure of the corresponding water intake in real time. The control unit is electrically connected to the electronically controlled proportional valve and all branch pressure sensors. The control unit adjusts the output of the electronically controlled proportional valve according to the detection results of each branch pressure sensor.

[0008] Furthermore, each process branch is equipped with a flow sensor to monitor the flow rate of the liquid entering the corresponding process branch in real time. The flow sensor is electrically connected to the control unit.

[0009] Furthermore, each process branch is equipped with a one-way valve, which is located downstream of the flow sensor to prevent the liquid from flowing back into the U-shaped circulation pipeline.

[0010] Furthermore, each process branch is equipped with a switching valve, which is located downstream of the check valve and is used to control the on / off state of the corresponding process branch.

[0011] Furthermore, all process branches are configured into several groups, and each group of process branches is connected to the U-shaped circulation pipeline through a common process water intake, in order to reduce the number of water intake ends on the U-shaped circulation pipeline.

[0012] Furthermore, an inlet pressure sensor is installed at the inlet to monitor the initial pressure of the external liquid supply source entering the system.

[0013] Furthermore, the electronically controlled proportional valve is an electronically controlled pressure reducing valve. Its input end is connected to a nitrogen source, and its output end is connected to the pneumatic control end of the back pressure valve. The control unit controls the backflow resistance of the return port by adjusting the nitrogen pressure output from the electronically controlled pressure reducing valve to the back pressure valve.

[0014] A current stabilization control method for multiple branches operating simultaneously, the method comprising the following steps: Step S1: With the flow stabilization system in the circulating liquid supply state, set the standard pressure value Pstd that the U-shaped circulation pipeline needs to maintain; Step S2: The control unit acquires the pressure signals from the pressure sensors of each branch in real time through the monitoring unit; Step S3: When the opening of the process branch causes the pressure signal detected by the corresponding branch pressure sensor to deviate from the standard pressure value Pstd, the control unit calculates the pressure deviation. Step S4: The control unit adjusts the output pressure of the electronically controlled proportional valve according to the pressure deviation, so as to compensate the pressure in the U-shaped circulation pipeline by changing the opening of the back pressure valve, so that the pressure signal detected by the branch pressure sensor returns to the standard pressure value Pstd range.

[0015] Furthermore, the adjustment logic for step S4 is as follows: If the pressure signal detected by the branch pressure sensor is lower than the standard pressure value Pstd, the intake pressure output from the electronically controlled proportional valve to the back pressure valve is increased to raise the set pressure of the back pressure valve, thereby forcibly increasing the pressure in the U-shaped circulation pipeline by increasing the backflow resistance. If the pressure signal detected by the branch pressure sensor is higher than the standard pressure value Pstd, the intake pressure output to the back pressure valve is reduced to lower the set pressure of the back pressure valve. This reduces the backflow resistance and guides the pressure of the U-shaped circulation pipeline to drop.

[0016] Furthermore, it also includes: Safety verification step S5: The control unit monitors the real-time flow of each process branch through the flow sensor and performs system status analysis in conjunction with the value of the inlet pressure sensor. If the flow of the process branch still fails to recover or the initial pressure is abnormal after pressure compensation in step S4, the control unit triggers an alarm.

[0017] The beneficial effects of this invention are: This invention constructs a U-shaped closed-loop circulation pipeline and coordinates it with a dynamic back pressure compensation mechanism at the return port. It utilizes the bidirectional liquid supply and fluid energy storage characteristics of the loop to achieve initial pressure balance at each water intake end. Under the condition of multiple branches operating simultaneously, sensors installed beside the water intake end capture local pressure drop deviations in real time. The control unit adjusts the return resistance of the back pressure valve to lock the liquid energy within the circulation pipeline, thereby dynamically compensating for the pressure loss caused by branch diversion and ensuring the stability of process flow under the condition of multiple stations operating simultaneously. Attached Figure Description

[0018] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the system composition principle according to an embodiment of the present invention; The labels in the diagram represent the following: 1-U-shaped circulation pipeline; 1a-Inlet; 1b-Return port; 2-Process branch; 3-Back pressure valve; 4-Electrically controlled pressure reducing valve; 5-Branch pressure sensor; 6-Flow sensor; 7-Check valve; 8-Switch valve; 9-Inlet pressure sensor. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] This embodiment provides a flow stabilization system for multiple branches operating simultaneously, aiming to solve the problems of main line pressure drop and flow fluctuation in each branch caused by the surge in instantaneous flow demand when multiple branches are opened at the same time.

[0022] For details, see Figure 1 As shown, this flow stabilization system includes a U-shaped circulation pipeline 1, which is in a closed loop state. The U-shaped circulation pipeline 1 has an inlet 1a and an outlet 1b. Multiple process branches 2 each have a water intake end connected to the U-shaped circulation pipeline 1.

[0023] In this structural design, the underlying principle of the U-shaped circulation pipeline 1, compared with the traditional unidirectional tree structure, is to stabilize pressure by constructing a closed loop with low pressure drop.

[0024] In a traditional tree topology, fluid flows in a single direction, and frictional resistance accumulates with the length of the pipeline, which inevitably results in the static pressure at the far end of the water intake being lower than that at the near end. Furthermore, when multiple branches are open, the pressure at the end drops exponentially due to the influence of the diversion at the front end.

[0025] The U-shaped structure of this scheme allows the liquid to circulate continuously within the main circuit. The water intake of each process branch 2 is actually supplied by both sides of the loop. This bidirectional replenishment mechanism significantly shortens the equivalent path of fluid transmission, thereby reducing pressure loss along the flow path.

[0026] Meanwhile, the large volume of circulating fluid stored in the closed loop has a physical momentum storage effect, which can act as a fluid buffer to absorb the instantaneous pressure shock caused by the opening and closing of branch valves, ensuring the uniformity and continuity of pressure distribution throughout the entire path.

[0027] To achieve pressure regulation, a back pressure regulating unit is provided at the return port 1b, including a back pressure valve 3 and an electrically controlled proportional valve connected to the execution control terminal of the back pressure valve 3. The electrically controlled proportional valve compensates for the pressure in the U-shaped circulation pipeline 1 by adjusting the opening of the back pressure valve 3.

[0028] The monitoring unit in the system includes multiple branch pressure sensors 5 installed on the U-shaped circulation pipeline 1. The number of branch pressure sensors 5 matches the number of water intake ends. Each branch pressure sensor 5 is installed next to the corresponding water intake end to monitor the pipeline pressure of the corresponding water intake end in real time.

[0029] The control unit is electrically connected to the electronically controlled proportional valve and all branch pressure sensors 5 respectively. The control unit adjusts the output of the electronically controlled proportional valve according to the detection results of each branch pressure sensor 5.

[0030] This U-shaped closed-loop structure, combined with the end-point back pressure regulation scheme, can utilize the circulating inertia of the fluid to maintain a consistent pressure base at each water intake point, and achieve rapid compensation of global pressure by changing the return fluid resistance.

[0031] Considering that opening too many water intake holes directly in the circulation pipeline may affect the pipeline strength and generate complex local turbulence, increasing the difficulty of pressure balancing, all process branches 2 are configured into several groups. Each group of process branches 2 is connected to the U-shaped circulation pipeline 1 through a common process water intake port, so as to reduce the number of water intake ends on the U-shaped circulation pipeline 1.

[0032] While maintaining the pressure of the main line, in order to further confirm the actual amount of medicine entering each chamber, each process branch 2 is equipped with a flow sensor 6 to monitor the flow rate of medicine entering the corresponding process branch 2 in real time. The flow sensor 6 is electrically connected to the control unit.

[0033] However, when the pressure at a certain point in the system drops instantaneously, there may be a risk that the liquid medicine may flow back from the branch end to the main line, which may lead to cross-contamination or metering errors. To address this, each process branch 2 is equipped with a one-way valve 7, which is located downstream of the flow sensor 6, to prevent the liquid medicine from flowing back into the U-shaped circulation pipeline 1.

[0034] In order to achieve independent control of the process sequence of each chamber, each process branch 2 is equipped with a switching valve 8. The switching valve 8 is located downstream of the one-way valve 7 and is used to control the opening and closing of the corresponding process branch 2.

[0035] In response to the inability of internal regulation to resolve fluctuations in the external liquid supply source, if there is a lack of monitoring at the liquid inlet 1a, the system may generate incorrect adjustment commands when the external liquid supply stops. Therefore, a liquid inlet pressure sensor 9 is installed at the liquid inlet 1a to monitor the initial pressure of the external liquid supply source entering the system.

[0036] At the actuator level for regulating the back pressure of return port 1b, specifically, the electronically controlled proportional valve adopts an electronically controlled pressure reducing valve 4, whose input end is connected to a nitrogen source and whose output end is connected to the pneumatic control end of the back pressure valve 3. The control unit controls the backflow resistance of return port 1b by adjusting the nitrogen pressure output from the electronically controlled pressure reducing valve 4 to the back pressure valve 3.

[0037] This embodiment also provides a current stabilization control method applied to the above system, the method comprising: Step S1: With the flow stabilization system in the circulating liquid supply state, set the standard pressure value Pstd that the U-shaped circulation pipeline 1 needs to maintain; Step S2: The control unit obtains the pressure signals of each branch pressure sensor 5 in real time through the monitoring unit. When the opening of the process branch 2 causes the pressure signal detected by the corresponding branch pressure sensor 5 to deviate from the standard pressure value Pstd, the process proceeds to step S3. Step S3: The control unit calculates the pressure deviation. Step S4: The control unit adjusts the output pressure of the electronically controlled proportional valve according to the pressure deviation, so as to compensate the pressure in the U-shaped circulation pipeline 1 by changing the opening of the back pressure valve 3, so that the pressure signal detected by the branch pressure sensor 5 returns to the standard pressure value Pstd range.

[0038] The specific adjustment logic is as follows: If the pressure signal detected by the branch pressure sensor 5 is lower than the standard pressure value Pstd, the intake pressure output by the electronically controlled proportional valve to the back pressure valve 3 is increased to increase the set pressure of the back pressure valve 3, thereby forcibly increasing the pressure in the U-shaped circulation pipeline 1 by increasing the backflow resistance. If the pressure signal detected by the branch pressure sensor 5 is higher than the standard pressure value Pstd, the intake pressure output to the back pressure valve 3 is reduced to lower the set pressure of the back pressure valve 3, thereby reducing the backflow resistance and guiding the pressure of the U-shaped circulation pipeline 1 to drop.

[0039] Finally, to address complex faults such as pipeline blockage or external source fluctuations, this method also includes: In safety verification step S5, the control unit monitors the real-time flow of each process branch 2 through the flow sensor 6 and performs system status analysis in conjunction with the value of the inlet pressure sensor 9. If the flow of process branch 2 still fails to recover or the initial pressure is abnormal after pressure compensation in step S4, the control unit triggers an alarm.

[0040] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its spirit and scope of protection, and such modifications or equivalent substitutions should also be considered as falling within the scope of protection of the embodiments of the present invention.

Claims

1. A current stabilization system applied to multiple branches operating simultaneously, characterized in that, include: A U-shaped circulation pipeline (1) has an inlet (1a) and a return outlet (1b). The process branch (2) is provided in multiple ways, and each process branch (2) has a water intake end connected to the U-shaped circulation pipeline (1); A back pressure regulating unit is provided at the return port (1b) and includes a back pressure valve (3) and an electrically controlled proportional valve connected to the execution control terminal of the back pressure valve (3). The electrically controlled proportional valve compensates for the pressure in the U-shaped circulation pipeline (1) by adjusting the opening of the back pressure valve (3). The monitoring unit includes multiple branch pressure sensors (5) installed on the U-shaped circulation pipeline (1). The number of branch pressure sensors (5) matches the number of water intake ends. Each branch pressure sensor (5) is installed on the side of the corresponding water intake end to monitor the pipeline pressure of the corresponding water intake end in real time. The control unit is electrically connected to the electronically controlled proportional valve and all the branch pressure sensors (5), and the control unit adjusts the output of the electronically controlled proportional valve according to the detection results of each branch pressure sensor (5).

2. The current stabilization system applied to multiple branches operating simultaneously, as described in claim 1, is characterized in that, Each of the process branches (2) is provided with a flow sensor (6) for real-time monitoring of the flow rate of the liquid medicine entering the corresponding process branch (2). The flow sensor (6) is electrically connected to the control unit.

3. The current stabilization system applied to multiple branches operating simultaneously, as described in claim 2, is characterized in that, Each of the process branches (2) is provided with a one-way valve (7), which is located downstream of the flow sensor (6) and is used to prevent the liquid medicine from flowing back into the U-shaped circulation pipeline (1).

4. The current stabilization system applied to multiple branches operating simultaneously, as described in claim 3, is characterized in that, Each of the process branches (2) is provided with a switch valve (8), which is located downstream of the one-way valve (7) and is used to control the opening and closing of the corresponding process branch (2).

5. The current stabilization system applied to multiple branches operating simultaneously, as described in claim 1, is characterized in that, All the process branches (2) are configured into several groups, and each group of process branches (2) is connected to the U-shaped circulation pipeline (1) through a common process water intake, so as to reduce the number of water intake ends on the U-shaped circulation pipeline (1).

6. The current stabilization system applied to multiple branches operating simultaneously according to claim 1, characterized in that, A liquid inlet pressure sensor (9) is provided at the liquid inlet (1a) to monitor the initial pressure of the external liquid supply source entering the system.

7. The current stabilization system applied to multiple branches operating simultaneously, as described in claim 1, is characterized in that, The electrically controlled proportional valve is an electrically controlled pressure reducing valve (4), whose input end is connected to a nitrogen source and whose output end is connected to the gas control end of the back pressure valve (3). The control unit controls the backflow resistance of the return port (1b) by adjusting the nitrogen pressure output from the electrically controlled pressure reducing valve (4) to the back pressure valve (3).

8. A current stabilization control method applied to a current stabilization system with multiple branches open simultaneously, applied to the current stabilization system as described in any one of claims 1-7, characterized in that, The method includes the following steps: Step S1: When the flow stabilization system is in the circulating liquid supply state, set the standard pressure value Pstd that the U-shaped circulation pipeline (1) needs to maintain; Step S2: The control unit acquires the pressure signals of each branch pressure sensor (5) in real time through the monitoring unit; Step S3: When the opening of the process branch (2) causes the pressure signal detected by the corresponding branch pressure sensor (5) to deviate from the standard pressure value Pstd, the control unit calculates the pressure deviation. Step S4: The control unit adjusts the output pressure of the electronically controlled proportional valve according to the pressure deviation, so as to compensate the pressure in the loop-shaped circulation pipeline (1) by changing the opening of the back pressure valve (3), so that the pressure signal detected by the branch pressure sensor (5) returns to the standard pressure value Pstd range.

9. The current stabilization control method according to claim 8, characterized in that, The adjustment logic for step S4 is as follows: If the pressure signal detected by the branch pressure sensor (5) is lower than the standard pressure value Pstd, the intake pressure output by the electronically controlled proportional valve to the back pressure valve (3) is increased to increase the set pressure of the back pressure valve (3), thereby forcibly increasing the pressure in the U-shaped circulation pipeline (1) by increasing the backflow resistance. If the pressure signal detected by the branch pressure sensor (5) is higher than the standard pressure value Pstd, the intake pressure output to the back pressure valve (3) is reduced to lower the set pressure of the back pressure valve (3) and the pressure of the loop-shaped circulation pipeline (1) is guided to drop by reducing the backflow resistance.

10. The current stabilization control method according to claim 8, characterized in that, Also includes: Safety verification step S5: The control unit monitors the real-time flow of each process branch (2) through the flow sensor (6) and performs system status analysis in conjunction with the value of the inlet pressure sensor (9). When the flow of the process branch (2) still fails to recover or the initial pressure is abnormal after pressure compensation in step S4, the control unit triggers an alarm prompt.

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