Microwave ion source multi-pin automatic impedance matching method and device

Abstract

The application discloses a microwave ion source multi-pin automatic impedance matching method and device, and relates to the field of microwave ion source technology.The microwave ion source multi-pin automatic impedance device comprises a microwave transmission line, pins, a reflected power detection unit, a driving mechanism and a controller, one end of the pin is inserted into the microwave transmission line and is driven to adjust the insertion depth by the driving mechanism, each pin moves independently, the reflected power detection unit is used for detecting the reflected power from the direction of the plasma load, and the controller is configured to execute the microwave ion source multi-pin automatic impedance matching method.Through the configuration of a plurality of pins capable of coordinated movement on the microwave transmission line, the reflected power detection unit capable of automatically detecting the reflected power and the controller executing a sequential-cyclic approximation algorithm, the plurality of pins are sequentially subjected to local optimal search, and multiple rounds of iteration are performed until the system global optimization, so that the reflected power is finally suppressed to the lowest level, the automatic matching and dynamic tracking are realized, and the optimal matching state is dynamically maintained during the working process.

Description

Technical Field

[0001] This invention relates to a method and apparatus for automatic impedance matching of microwave ion sources with multiple pins. Background Technology

[0002] A microwave ion source is a device that uses microwave energy to generate, accelerate, or control electron beams. When a microwave ion source is operating, microwave power needs to be efficiently coupled from the generator to the plasma cavity via a waveguide or coaxial line. Because the impedance of the plasma load dynamically changes with parameters such as gas pressure, flow rate, and voltage intensity, it may mismatch with the characteristic impedance of the microwave transmission line, causing some power to be reflected, reducing energy utilization efficiency, and potentially damaging the microwave source in severe cases. Currently, the industry commonly uses adjustable pins inserted into the microwave transmission line (such as a waveguide) to form an impedance matching network. Traditional adjustment methods rely entirely on manual adjustment by the operator, which has the following significant drawbacks.

[0003] 1. Low efficiency: Each start-up or change of process parameters requires repeated manual attempts, which is time-consuming and labor-intensive.

[0004] 2. Limited accuracy: It relies on human experience and is difficult to achieve the optimal matching point.

[0005] 3. Unable to dynamically track: It cannot follow the changes in load impedance in real time during the process, resulting in drift of the matching state and poor process stability.

[0006] 4. Poor consistency: The results of adjustments made by different personnel or at different times vary, affecting the repeatability of the process. Summary of the Invention

[0007] The purpose of this invention is to provide an automatic impedance matching method for microwave ion sources with multiple pins, so as to solve the problems of low efficiency, limited accuracy, inability to dynamically track and poor consistency in the current method of manually adjusting the position of the pins for impedance matching.

[0008] This invention is achieved through the following technical solution: The steps of the automatic impedance matching method for multi-pin microwave ion sources are as follows: S1: Several pins are moved to their initial positions under control; S2: Set the maximum number of outer loop iterations; S3: Enter the first external circulation. During the first external circulation, each pin moves in sequence according to the preset order. S4: Obtain the pin position Pos and the corresponding reflection power value P_refl; S5: Based on the obtained pin position Pos and reflected power value P_refl, obtain the trend curve of reflected power changing with pin position, obtain the minimum power value P_min based on the trend curve, and lock the pin at the pin position Pos_min corresponding to the minimum power value P_min. S6: In the first external cycle, if the lowest power value P_min that occurs when a pin moves is lower than the absolute threshold, the matching is considered successful and the adjustment ends. In the first outer loop, if the minimum power value P_min that occurs when all pins move is higher than the absolute threshold, then a new round of outer loop is entered. S7: In the new round of external circulation, each pin moves in sequence according to the preset order; S8: Obtain the pin position Pos and the corresponding reflection power value P_refl; S9: Based on the obtained pin position Pos and reflected power value P_refl, obtain the trend curve of reflected power changing with pin position, obtain the minimum power value P_min based on the trend curve, and lock the pin at the pin position Pos_min corresponding to the minimum power value P_min. S10: In the new round of external circulation, if the lowest power value P_min that occurs when a pin moves is lower than the absolute threshold, the matching is determined to be successful and the adjustment ends. In a new round of external circulation, if the minimum power value P_min that occurs when all pins move is higher than the absolute threshold, then enter a new round of external circulation again, repeating steps S7-S10 until the minimum power value P_min that occurs when a pin moves is lower than the absolute threshold or the maximum number of external circulations is reached, then end the adjustment.

[0009] Furthermore, in S5 and S9, if the trend curve first decreases and then increases, the minimum power value P_min and its corresponding pin position Pos_min are recorded, and the pin is driven to the pin position Pos_min corresponding to the minimum power value P_min; if the trend curve continues to increase or decreases, the pin is stopped at the current stroke end point or at the pin position Pos_min corresponding to the minimum power value P_min.

[0010] Furthermore, in steps S3 and S7, each pin moves continuously or stepwise within its entire or part of its effective stroke.

[0011] Further, in steps S4 and S8, the reflected power value P_refl and the pin position Pos are recorded at a fixed sampling interval. In steps S5 and S9, either in real time or after a period of movement, the trend curve of the reflected power changing with the pin position is fitted or analyzed based on the recorded reflected power value P_refl and the pin position Pos.

[0012] Furthermore, there are 3 pins; and / or the maximum number of external loops is at least 2.

[0013] Furthermore, the absolute threshold is 0–10W.

[0014] To address the problems of low efficiency, limited accuracy, inability to dynamically track, and poor consistency in current methods of manually adjusting pin positions for impedance matching, this invention provides a multi-pin automatic impedance matching method for microwave ion sources. Correspondingly, a multi-pin automatic impedance matching device for microwave ion sources is provided, comprising a microwave transmission line, pins, a reflection power detection unit, a drive mechanism, and a controller. Several pins are present, each with one end inserted into the microwave transmission line and its insertion depth adjusted by the drive mechanism. Each pin moves independently. The reflection power detection unit detects the reflected power from the plasma load direction. The controller is configured to execute the multi-pin automatic impedance matching method for microwave ion sources.

[0015] Furthermore, the microwave transmission line has an inner cavity, and a plurality of the pins are inserted into the inner cavity in the radial direction of the microwave transmission line and arranged side by side in the axial direction of the microwave transmission line.

[0016] Furthermore, the reflected power detection unit includes a directional coupler and a detector.

[0017] Furthermore, the driving mechanism includes a plurality of driving modules corresponding one-to-one with the plurality of pins, and each pin is driven by the corresponding driving module to adjust the insertion depth.

[0018] The advantage of this technical solution is that by configuring several pins that can move in coordination on the microwave transmission line, a reflection power detection unit that can automatically detect the reflection power, and a controller that executes a sequential-cyclic approximation algorithm, the pins are made to perform local optimal search one by one and iterate multiple times until the system is globally optimal, thus suppressing the reflection power to the lowest level, achieving fast automatic matching and dynamic tracking, and dynamically maintaining the best matching state during operation. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0021] Figure 1 This is a flowchart of the automatic impedance method for a microwave ion source with three pins according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the microwave ion source multi-pin automatic impedance device according to an embodiment of the present invention. Detailed Implementation

[0022] 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.

[0023] Example: Figure 2 As shown, the microwave ion source multi-pin automatic impedance matching device includes a microwave transmission line 1, pins 2, a reflection power detection unit 3, a drive mechanism 4, and a controller 5. There are several pins 2, one end of which is inserted into the microwave transmission line 1 and the insertion depth is adjusted by the drive mechanism 4. Each pin 2 moves independently. The reflection power detection unit 3 is used to detect the reflected power from the direction of the plasma load. The controller 5 is configured to execute the microwave ion source multi-pin automatic impedance matching method. The microwave transmission line 1 is connected to a vacuum cavity 7 via an antenna 6. A microwave source 8 is located at the end of the microwave transmission line 1 away from the vacuum cavity 7. The microwave transmission line 1 can be, but is not limited to, a waveguide.

[0024] In this embodiment of the invention, the microwave transmission line 1 has an inner cavity 101, and a plurality of pins 2 are inserted into the inner cavity 101 in the radial direction of the microwave transmission line 1 and arranged side by side in the axial direction of the microwave transmission line 1.

[0025] In this embodiment of the invention, the reflection power detection unit 3 includes a directional coupler (not shown in the figure) and a detector (not shown in the figure). The reflection power detection unit 3 is used to detect the reflection power from the direction of the plasma load and output the corresponding analog or digital detection signal.

[0026] In this embodiment of the invention, the driving mechanism 4 includes a plurality of driving modules 401 corresponding one-to-one with a plurality of pins 2, and each pin 2 is driven by the corresponding driving module 401 to adjust the insertion depth. Specifically, the driving module 401 is a stepper motor or servo motor in conjunction with a lead screw mechanism.

[0027] In this embodiment of the invention, the controller 5 is electrically connected to the reflection power detection unit 3 and the drive mechanism 4, respectively.

[0028] like Figure 1 As shown, the automatic impedance matching method for multi-pin microwave ion sources involves the following steps: S1: Several pins 2 are moved to their initial positions under control; S2: Set the maximum number of outer loop iterations; S3: Enter the first external circulation. In the first external circulation, each pin 2 moves in sequence according to the preset order. S4: Obtain the pin position Pos and the corresponding reflection power value P_refl; S5: Based on the obtained pin position Pos and reflected power value P_refl, obtain the trend curve of reflected power changing with the position of pin 2. Based on the trend curve, obtain the minimum power value P_min and lock pin 2 at the pin position Pos_min corresponding to the minimum power value P_min. S6: In the first external cycle, if the lowest power value P_min that occurs when pin 2 moves is lower than the absolute threshold, the matching is considered successful and the adjustment ends. In the first outer loop, if the minimum power value P_min that occurs when all pins 2 move is higher than the absolute threshold, then a new round of outer loop is entered. S7: In the new round of external circulation, each pin 2 moves in sequence according to the preset order; S8: Obtain the pin position Pos and the corresponding reflection power value P_refl; S9: Based on the obtained pin position Pos and reflected power value P_refl, obtain the trend curve of reflected power changing with the position of pin 2, obtain the minimum power value P_min based on the trend curve, and lock pin 2 at the pin position Pos_min corresponding to the minimum power value P_min. S10: In the new round of external circulation, if the lowest power value P_min that occurs when pin 2 moves is lower than the absolute threshold, the matching is determined to be successful and the adjustment ends. In a new round of external circulation, if the minimum power value P_min that occurs when all pins move is higher than the absolute threshold, then enter a new round of external circulation again, repeating steps S7-S10 until the minimum power value P_min that occurs when a pin moves is lower than the absolute threshold or the maximum number of external circulations is reached, then end the adjustment.

[0029] In summary, this embodiment provides a microwave ion source multi-pin automatic impedance device and method to solve the problems of low efficiency, limited accuracy, inability to dynamically track, and poor consistency in the current method of manually adjusting the position of the pins 2 for impedance. It mainly involves configuring several pins 2 that can move in coordination on the microwave transmission line 1, a reflection power detection unit 3 that can automatically detect the reflected power, and a controller 5 that executes a sequential-cyclic approximation algorithm. The pins 2 are then subjected to local optimal search one by one, and the process is iterated multiple times until the system is globally optimal. Finally, the reflected power is suppressed to the lowest level, achieving rapid automatic matching and dynamic tracking, and dynamically maintaining the best matching state during operation.

[0030] Steps S4 and S5 involve performing each pin individually.

[0031] In step S6, during the first outer loop, if the lowest power value P_min that occurs when a pin 2 moves is lower than the absolute threshold, the matching is considered successful and the adjustment ends. This means that if the reflected power value P_refl detected when a pin moves is lower than the absolute threshold, then the reflected power value P_refl is defined as the lowest power value P_min of that pin, and the entire adjustment ends immediately (other pins that have not moved do not need to be moved either).

[0032] Steps S8 and S9 involve performing each pin individually.

[0033] In step S10, if the lowest power value P_min that occurs when a pin 2 moves is lower than the absolute threshold in the new outer loop, the matching is determined to be successful and the adjustment ends. This means that if the reflected power value P_refl detected when a pin moves is lower than the absolute threshold, then the reflected power value P_refl is defined as the lowest power value P_min of that pin, and the entire adjustment ends immediately (other pins that have not moved do not need to be moved either).

[0034] In this embodiment of the invention, in steps S5 and S9, if the trend curve first decreases and then increases, the minimum power value P_min and its corresponding pin position Pos_min are recorded, and the pin 2 is driven to the pin position Pos_min corresponding to the minimum power value P_min. If the trend curve first decreases and then increases, a local minimum point is determined, and the pin 2 is driven to the pin position Pos_min corresponding to the minimum power value P_min, which helps to quickly lock the pin position Pos_min.

[0035] In this embodiment of the invention, in steps S5 and S9, if the trend curve continues to rise or fall, the pin 2 is stopped at the current travel endpoint or at the pin position Pos_min corresponding to the lowest power value P_min. If the pin 2 does not detect a "falling then rising" trend throughout its movement, the pin 2 is stopped at the current travel endpoint or at the position with the lowest reflected power, which is beneficial for quickly locking the pin position Pos_min.

[0036] In this embodiment of the invention, in steps S3 and S7, each pin 2 moves continuously or in steps within its entire or part of its effective stroke. This arrangement ensures stable movement of the pin 2 and improves the accuracy of the detection.

[0037] In this embodiment of the invention, in steps S4 and S8, the reflected power value P_refl and the pin position Pos are recorded at a fixed sampling interval. In steps S5 and S9, either in real time or after a period of movement, the trend curve of the reflected power changing with the position of the pin 2 is fitted or analyzed based on the recorded reflected power value P_refl and the pin position Pos.

[0038] In this embodiment of the invention, there are 3 pins 2, and the maximum number of external cycles is at least 2.

[0039] In this embodiment of the invention, the absolute threshold is 0 to 10W.

[0040] It should be understood that the terms "first," "second," etc., are used in this invention to describe various information, but this information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of this invention, "first" information can also be referred to as "second" information, and similarly, "second" information can also be referred to as "first" information. In addition, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0041] The above description provides one or more embodiments in conjunction with specific content, and does not imply that the specific implementation of the present invention is limited to these descriptions. Any methods or structures that are similar to or identical to those of the present invention, or any technical deductions or substitutions made based on the concept of the present invention, should be considered as protected by the present invention.

Claims

1. A multi-pin automatic impedance matching method for microwave ion sources, characterized in that, The steps are as follows: S1: Several pins are moved to their initial positions under control; S2: Set the maximum number of outer loop iterations; S3: Enter the first external circulation. During the first external circulation, each pin moves in sequence according to the preset order. S4: Obtain the pin position Pos and the corresponding reflection power value P_refl; S5: Based on the obtained pin position Pos and reflected power value P_refl, obtain the trend curve of reflected power changing with pin position, obtain the minimum power value P_min based on the trend curve, and lock the pin at the pin position Pos_min corresponding to the minimum power value P_min. S6: In the first external cycle, if the lowest power value P_min that occurs when a pin moves is lower than the absolute threshold, the matching is considered successful and the adjustment ends. In the first outer loop, if the minimum power value P_min that occurs when all pins move is higher than the absolute threshold, then a new round of outer loop is entered. S7: In the new round of external circulation, each pin moves in sequence according to the preset order; S8: Obtain the pin position Pos and the corresponding reflection power value P_refl; S9: Based on the obtained pin position Pos and reflected power value P_refl, obtain the trend curve of reflected power changing with pin position, obtain the minimum power value P_min based on the trend curve, and lock the pin at the pin position Pos_min corresponding to the minimum power value P_min. S10: In the new round of external circulation, if the lowest power value P_min that occurs when a pin moves is lower than the absolute threshold, the matching is determined to be successful and the adjustment ends. In a new round of external circulation, if the minimum power value P_min that occurs when all pins move is higher than the absolute threshold, then enter a new round of external circulation again, repeating steps S7-S10 until the minimum power value P_min that occurs when a pin moves is lower than the absolute threshold or the maximum number of external circulations is reached, then end the adjustment.

2. The automatic impedance matching method for a microwave ion source with multiple pins according to claim 1, characterized in that, In S5 and S9, if the trend curve first decreases and then increases, the minimum power value P_min and its corresponding pin position Pos_min are recorded, and the pin is driven to the pin position Pos_min corresponding to the minimum power value P_min. If the trend curve continues to rise or continue to fall, then stop the pin at the current travel endpoint or at the pin position Pos_min corresponding to the minimum power value P_min.

3. The automatic impedance matching method for a microwave ion source with multiple pins according to claim 1, characterized in that, In steps S3 and S7, each pin moves continuously or stepwise within its entire or part of its effective stroke.

4. The automatic impedance matching method for a microwave ion source with multiple pins according to claim 1, characterized in that, In steps S4 and S8, the reflected power value P_refl and the pin position Pos are recorded at a fixed sampling interval. In steps S5 and S9, either in real time or after a certain movement, the trend curve of the reflected power changing with the pin position is fitted or analyzed based on the recorded reflected power value P_refl and the pin position Pos.

5. The automatic impedance matching method for a microwave ion source with multiple pins according to claim 1, characterized in that, There are 3 pins; and / or the maximum number of external loops is at least 2.

6. The automatic impedance matching method for a microwave ion source with multiple pins according to claim 1, characterized in that, The absolute threshold is 0 to 10W.

7. A microwave ion source multi-pin automatic impedance device, characterized in that, The device includes a microwave transmission line, pins, a reflection power detection unit, a drive mechanism, and a controller. There are several pins, one end of each pin is inserted into the microwave transmission line and the insertion depth is adjusted by the drive mechanism. Each pin moves independently. The reflection power detection unit is used to detect the reflection power from the direction of the plasma load. The controller is configured to perform the microwave ion source multi-pin automatic impedance matching method according to any one of claims 1-6.

8. The microwave ion source multi-pin automatic impedance device according to claim 7, characterized in that, The microwave transmission line has an inner cavity, and a plurality of pins are inserted into the inner cavity in the radial direction of the microwave transmission line and arranged side by side in the axial direction of the microwave transmission line.

9. The microwave ion source multi-pin automatic impedance device according to claim 7, characterized in that, The reflected power detection unit includes a directional coupler and a detector.

10. The microwave ion source multi-pin automatic impedance device according to claim 7, characterized in that, The driving mechanism includes several driving modules that correspond one-to-one with the pins, and each pin is driven by the corresponding driving module to adjust the insertion depth.

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