A radio frequency automatic matching method and system for vacuum coating

Abstract

This invention discloses an automatic radio frequency matching method and system for vacuum coating, applied to a radio frequency power supply system for CCP cavity plasma vacuum coating. The method includes rapidly performing a pre-matching point search in an FPGA to obtain and adjust the optimal parallel and series capacitor values ​​corresponding to the current load. In the current round, variable rotation and local search are performed on the parallel and series adjustable capacitors to obtain optimized capacitor values. The corresponding objective function value is calculated; if it meets the preset accuracy requirement, the search stops and the current capacitor value is output; if the objective is not achieved, the difference between the current reflection coefficient and the reflection coefficient of the previous round is calculated; if this difference is less than a set minimum tolerance threshold, the search stops and the current capacitor value is output. The system includes an initialization setting module, a search module, and an iterative judgment module. By using this invention, impedance matching can be quickly converged and completed. This invention can be widely applied in the field of impedance matching technology.

Description

Technical Field

[0001] This invention relates to the field of impedance matching technology, and in particular to an automatic radio frequency matching method and system for vacuum coating. Background Technology

[0002] In plasma RF power supply systems, the power supply couples power to the load (plasma / exciter / resonant structure) through a matching network. Due to variations in discharge state, gas pressure, gas composition, and process stages, the equivalent impedance of the load exhibits significant time-varying and nonlinear characteristics, causing the matching state to drift over time. This manifests as an increase in reflection coefficient, a rise in reflected power, a decrease in coupling efficiency, and a deterioration in discharge stability. In engineering practice, it is often difficult to obtain accurate models and parameters of the load impedance in real time. Therefore, online adaptive impedance matching based on reflection information is commonly employed: using the reflection coefficient (or equivalent index) at the entrance of the matching network as feedback, the adjustable components in the matching network (e.g., parallel capacitors, series capacitors) and the excitation frequency are automatically adjusted to gradually decrease the reflection coefficient until it reaches a threshold, thereby achieving online matching control without the need for explicit impedance acquisition.

[0003] However, under the condition that the load impedance is unknown and fluctuates drastically with ignition / extinguishing and operating conditions during capacitively coupled plasma (CCP) discharge, traditional matching algorithms that rely solely on local search or single parameter tuning methods are prone to convergence difficulties, excessive search steps, and getting trapped in local optima. Furthermore, they may cause EMI and device stress risks due to excessive reflected power. Summary of the Invention

[0004] In view of this, in order to solve the technical problem that most existing RF automatic matching methods for vacuum coating rely on a single parameter tuning method for impedance matching, resulting in slow convergence and the system bearing large reflected power for a long time, the present invention proposes an RF automatic matching method for vacuum coating. This method is applied to an RF power supply system for CCP cavity plasma vacuum coating, wherein: The radio frequency power supply system for CCP cavity plasma vacuum coating includes a signal detection circuit, an FPGA power management chip, a parallel adjustable capacitor, and a series adjustable capacitor. The method includes: Initialization: Set all initial parameters and specify the maximum number of search rounds.

[0005] Pre-matching point search: Quickly perform a pre-matching point search in the FPGA to obtain the optimal parallel and series capacitor values ​​corresponding to the current load, and adjust the two adjustable capacitors to the target position; Local search and target determination: In the current round, a local search is performed on the parallel and series adjustable capacitors to obtain the optimized capacitance values. The corresponding objective function value is calculated. If the value meets the preset accuracy requirement, the search stops, the current capacitance value is output and marked as "successfully converged".

[0006] Convergence check: If the goal is not achieved, calculate the difference between the current reflection coefficient and the reflection coefficient of the previous round. If the difference is less than the set minimum tolerance threshold, stop the search, output the current capacitance value and mark it as "progressing convergence"; otherwise, update the reflection coefficient record and return to the search step for the next round of iteration.

[0007] In addition, if the number of iterations exceeds the maximum search rounds and the preset target is still not reached, the automatic frequency adjustment function is activated. By making minor adjustments to the power supply operating frequency, the system can jump out of the local minimum point and guide the reflection coefficient magnitude to converge toward the target value.

[0008] During operation, if a sudden change in the CCP cavity load causes the plasma glow to extinguish and the reflection coefficient modulus at the current frequency exceeds the intermediate threshold, the system will immediately revert to the pre-matching branch, quickly pull the intermediate threshold back into the controllable region, and achieve re-ignition. In some embodiments, the local search step specifically includes: Save the current target value and proceed to the next round: Record the target function value for the current round, and then start a new round of search.

[0009] Obtain capacitor parameters: Read the current value of the capacitor to be adjusted, the step interval, and the allowable adjustment range (minimum to maximum value).

[0010] Forward search attempt: Increase the current capacitance value by one step interval to obtain a trial value. If the trial value is within the allowable range, calculate the corresponding objective function value and compare it with the value saved in the first step: If the new target value is better (smaller), accept the trial value and continue to adjust gradually in the same direction until it cannot be improved or exceeds the range.

[0011] If the new target value is not better (larger or equal), abandon the positive attempt and switch to the negative search.

[0012] Positive out-of-bounds handling: If the positive probe value exceeds the allowed range, skip the positive search and proceed to the negative search.

[0013] Negative search attempt: Reduce the current capacitance value by one step to obtain a trial value. If this value is within range, calculate the new target value: If the new target value is better, accept the trial value and continue to adjust gradually in the negative direction until it cannot be improved or exceeds the range.

[0014] If the new target value is not optimal, the search for the current capacitor variable ends, and the process switches to the next adjustable capacitor (e.g., switching from a parallel capacitor to a series capacitor) and performs a similar operation.

[0015] Negative out-of-bounds handling: If the negative probe value exceeds the range, the search for the current variable also ends, and the search switches to the next variable.

[0016] This process is repeated until all variables can no longer be improved, or other termination conditions are met.

[0017] Based on the overall process of the above method, the present invention also proposes an automatic radio frequency matching system for vacuum coating. The system is applied to the automatic radio frequency matching method for vacuum coating as described above, and includes an initialization setting module, a search module, and an iterative judgment module.

[0018] Based on the above scheme, this invention provides an automatic RF matching method and system for vacuum coating. It adopts a multi-level matching process that combines "pre-matching point search, hybrid optimization strategy and automatic frequency tuning" to enhance global guidance capability and adaptability to operating conditions. Compared with the local iterative method that only uses variable rotation and gradient descent, this multi-level strategy can reduce the probability of getting trapped in local optima or plateau regions, thereby improving the convergence speed and robustness of automatic impedance matching under complex time-varying loads. Furthermore, a pre-matching point search mechanism is introduced to quickly search for the target values ​​of series and parallel capacitors corresponding to the impedance state when the cavity is not ignited, so that the reflection coefficient can be significantly reduced in a short time, thereby reducing the impact risk of high reflection power on the front-end RF power supply and output network. Attached Figure Description

[0019] Figure 1 This is a flowchart of the steps of an automatic radio frequency matching method for vacuum coating according to the present invention; Figure 2 This is a schematic diagram of the framework of the matcher system; Figure 3 This is a schematic diagram showing the variation and rate of change of the magnitude of the reflection coefficient of the matching circuit topology of the present invention with series capacitance, parallel capacitance and frequency; Figure 4 This is a surface plot showing the relationship between the objective function and state x in this invention; Figure 5 This is the logic flowchart of variable rotation in this invention; Figure 6 This is a flowchart illustrating the logic of the local search in this invention; Figure 7 It is an enhancement Simplified diagram of a type-matching circuit; Figure 8 This is a logic flowchart of the automatic frequency modulation mode of the present invention; Figure 9 This is a schematic diagram of the input impedance deviation mapping of the present invention. Detailed Implementation

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

[0021] It should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings. Unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0022] It should be understood that the terms "system," "apparatus," "unit," and / or "module" used in this application are a method of distinguishing different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they may be replaced by other expressions.

[0023] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "a," and / or "the" are not specifically singular and may include the plural. Generally, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements. An element defined by the phrase "comprising an..." does not exclude the presence of other identical elements in the process, method, product, or apparatus that includes the element.

[0024] In the description of the embodiments of this application, "a plurality of" refers to two or more. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0025] Furthermore, flowcharts are used in this application to illustrate the operations performed by the system according to embodiments of this application. It should be understood that the preceding or following operations are not necessarily performed precisely in sequence. Instead, the steps can be processed in reverse order or simultaneously. Additionally, other operations can be added to these processes, or one or more steps can be removed from them.

[0026] Reference Figure 1The diagram below is a schematic flowchart of an optional example of the automatic radio frequency matching method for vacuum coating proposed in this invention, wherein: This method is applied to, for example Figure 2 The illustrated RF power supply system for CCP cavity plasma vacuum coating includes a signal detection circuit, an FPGA power management chip, a parallel adjustable capacitor, and a series adjustable capacitor. In the CCP cavity plasma vacuum coating RF power supply system, the parallel adjustable capacitor is adjusted by... and series capacitor Automatic impedance matching is achieved. The FPGA is used to execute the automatic impedance matching method and drive the motor to adjust the vacuum adjustable capacitor. The ARM is used to control the human-machine interface module, allowing users to configure the matching device accordingly.

[0027] The matching method proposed in this embodiment may include, but is not limited to, the following steps: Step S1: Initialize all parameters and set the maximum number of search rounds. ; Step S2: Call the pre-matching point search to quickly search for the target capacitor pair corresponding to the current load in the FPGA, and adjust the parallel adjustable capacitor and the series adjustable capacitor to the target position. Step S3: Update the number of rounds ; Step S4: Activate the hybrid strategy for the parallel adjustable capacitor. and series adjustable capacitor Perform a search and compare the searched objective function value with the preset objective value. If the current objective function value is less than the preset objective value, the search ends and returns. If the search is successful, the current round and the corresponding values ​​of the parallel and series adjustable capacitors are output. Otherwise, proceed to the next step. Step S5: Determine the difference between the current reflection coefficient and the previous reflection coefficient. If the difference is less than the minimum tolerance value, the process ends, indicating progress convergence, and the parallel adjustable capacitor and series adjustable capacitor for the current round are output. Otherwise, return to step S3 and start the next round of search.

[0028] Step S6, if it appears If the target is not reached, automatic frequency adjustment is triggered, which slightly adjusts the power supply operating frequency to cross the local minimum and converge to the target reflection coefficient magnitude. in, Figure 3 This invention illustrates the variation and rate of change of the magnitude of the reflection coefficient of the matching circuit topology with series capacitance, parallel capacitance, and frequency. The derivative of the reflection coefficient magnitude with respect to variables represents the rate of change. a) represents the relationship between the magnitude of the reflection coefficient and the parallel capacitance. The relationship between b) and the magnitude of the reflection coefficient and the series capacitance. The relationship between the reflection coefficient and the frequency is shown in the figure. As can be seen from the figure, for the matching circuit designed in this invention, within the range of the corresponding variables, the series capacitor has the greatest influence on the reflection coefficient, the parallel capacitor has the greatest influence, and the frequency has the least influence.

[0029] Figure 4 The figure shows the objective function in this invention. With state The relationship surface diagram shows that the red area represents the matched circuit. Time state solution Feasible solution region. In this invention, a successful match is determined when the magnitude of the reflection coefficient is below 0.1. The optimized value of the objective function of the adaptive matching strategy is... .

[0030] In this embodiment, a pre-matching point search mechanism is introduced for the pre-ignition operating conditions. Unlike the commonly used method in existing technologies that involves "variable rotation or gradient descent iteratively from any initial point," this invention, in the stage where the cavity is not ignited, the reflection coefficient is high, and measurement accuracy is limited, does not rely on local gradient information. Instead, based on the known matching network structure and the discrete characteristics of the adjustable capacitor, it directly obtains the target combination of series and parallel capacitors corresponding to the current load through parallel or high-speed exhaustive search within the feasible solution domain using FPGA, and adjusts the matcher to the pre-matching point in one go. Existing technologies typically lack dedicated processing mechanisms for high reflection and weak signal conditions before ignition, easily leading to inefficient iterations under prolonged high reflection conditions; while this invention, through pre-matching point search, achieves a fundamental difference in technical path by "replacing local exploration with global positioning."

[0031] In a hybrid strategy combining variable rotation and gradient descent, direction determination and stage exit logic are introduced. Existing variable rotation methods often use fixed step sizes or empirical step sizes, while gradient descent methods frequently update variables directly based on difference results. Both can lead to ineffective adjustment, over-adjustment, or repeated fine-tuning near the matching point. This invention, before each variable adjustment, clarifies the direction the variable should be adjusted by direction probing, avoiding ineffective direction searches. Simultaneously, it combines two exit criteria: "stage success" and "stage stabilization," to promptly end the current variable search when the objective function shows limited improvement or has entered a flat region, thereby reducing unnecessary executor actions and time consumption. This difference is not only reflected in the adjustment effect but also in the specific search logic, exit conditions, and execution process design.

[0032] This invention separates power frequency regulation from conventional parallel variables and places it at the end of a multi-level matching process, while constructing a three-level linkage structure of "pre-matching point search, hybrid strategy, and automatic frequency tuning". In existing technologies, frequency is usually treated as an optimization variable parallel to capacitance in the iteration. However, in practical systems, the frequency adjustment range is limited, its ability to improve reflection is restricted, and it can easily interfere with the convergence process of capacitance search. This invention first uses pre-matching and hybrid strategies to reduce the reflection coefficient to a low level, and then calls an independent automatic frequency tuning module for fine correction, forming a clear division of labor in the technical process; and when there is a sudden change in load or an abnormal increase in reflection, it quickly retreats to the pre-matching branch through an intermediate threshold mechanism to avoid the system being in a high reflection stress state for a long time. Compared with the single local iterative structure of existing technologies, this invention demonstrates stronger global guidance capability and engineering robustness in its overall architecture.

[0033] In some feasible embodiments, the mixing strategy in steps S4 to S5, and The rotation of the two variables and the exit logic during local searches can greatly affect the execution efficiency of the entire strategy. This invention provides a detailed design for the logic in these two areas: like Figure 5 The diagram shows the flowchart of the variable rotation logic. For ease of explanation, this logic is named adjust_parameter( This logic, besides involving the rotation between two variables, also includes searching for the direction when searching a single variable. The main steps are as follows: (1) Obtain the capacitance value of the currently searched capacitor. Step interval and the adjustable range of the vacuum capacitor ; (2) Calculate and save the current value of the objective function. And search for the target capacitance value in the positive direction, determine the current capacitance value of the adjustable capacitor, if If the value is valid, proceed to step (3); otherwise, discard the current capacitance value and proceed to step (5). (3) Calculate the objective function value after the forward search. And judge the objective function value before and after the change, if If the condition is met, proceed to step (4); otherwise, proceed to step (5).

[0034] (4) Set the current capacitance value Updated to And continue to adjust the capacitor in the positive direction. value (5) Adjust the capacitor in the negative direction and calculate the target function value after adjustment. Compare it with the objective function value from the previous time step; if... If the condition is met, proceed to step (6); otherwise, end the search for the current variable and switch to another variable for the search. (6) Set the current capacitance value Updated to And continue to adjust the capacitor in the negative direction. According to the magnitude of reflection and The relationship between the changes reveals that, on both sides of the matching state point, the closer to the matching state point, the smaller the partial derivative with respect to the capacitance, and the smaller the impact of capacitance transformation on the magnitude of the reflection coefficient. Near the matching state point, if the adjustment step is very small, even if the adjustment direction is correct, it contributes little to reducing the magnitude of the reflection coefficient and also causes significant time waste. This indicates that the adjustment of the reflection magnitude is stabilizing in stages, and the better choice at this point is to exit the single-round search. Therefore, the exit logic for local search has two termination states: stage success and stage stabilization. For ease of subsequent description, this logic is named `run_optimization(`. ), like Figure 6 The flowchart shown is for this logic, and the main steps are as follows: (1) Save the value of the objective function of the current round and proceed to step (2); (2) Start the next round and update. ,make Proceed to step (3); (3) Call the variable rotation logic run_optimization( ) Perform the capacitor search, calculate the value of the objective function after the search, and compare it with the target value. If the current objective function value is less than the target value, the process ends and returns, indicating that the stage is successful. Otherwise, proceed to step (4). (4) Calculate the difference between the current objective function value and the objective function value before the search. If the difference is less than the minimum tolerance value for the change in the reflection coefficient, then end and return, indicating that the stage has stabilized; otherwise, update the objective function value and proceed to the next round.

[0035] The derivation of the objective function is as follows: right Figure 2 The circuit part in the simplified form is obtained Figure 7 The circuit shown, in which and They are respectively: Analysis of this matching circuit yields the following input impedance when viewed from the end of the transmission line towards the matching network: Set the CCP cavity load impedance for: The above equation is rearranged to obtain the input impedance of the matched circuit. for: Matching state can be achieved using voltage reflection coefficient To characterize the RF transmission line impedance in an RF power supply. According to transmission line theory, we can obtain: The above equation is the objective function, which can be seen to be related to the parallel adjustable capacitor. Series adjustable capacitor and frequency The relevant three-dimensional functions.

[0036] in, Indicates: the input impedance of the matching circuit; Indicates: the input admittance of the matcher; The imaginary unit; Indicates: angular frequency; This refers to the parallel capacitor at the input of the matching circuit, and its position in the circuit is as follows: Figure 2 As shown; The adjustable capacitor connected in parallel in the matching circuit is positioned as follows: Figure 2 As shown; The parallel inductor at the input of the matching circuit is located as follows: Figure 2 As shown; Indicates: The matching circuit is connected in series with an adjustable capacitor, and its position in the circuit is as follows: Figure 2 As shown; Indicates: A capacitor is connected in parallel at the output of the matching circuit, and its position in the circuit is as follows: Figure 2 As shown Represents the real part of the cavity load impedance; Indicates: the imaginary part of the cavity impedance.

[0037] In some feasible embodiments, the automatic frequency modulation mode of step S6 refers to Figure 8 Specifically, it includes: During the initialization phase, obtain the current frequency. and its corresponding reflection coefficient modulus Then, we first tried to adjust the frequency in the direction of increasing frequency, and then adjusted it to... and will and Compare; if If the frequency decreases, continue to gradually adjust it in the direction of increase; otherwise, decrease the frequency. Adjust the frequency in the same way. ,Compare and ;like If it decreases, continue adjusting in the decreasing direction. If no change is observed after two trials... The decrease indicates that the current frequency is near the operating point where the system is close to perfect matching, and frequency adjustment can be terminated. The above process revolves around "comparison-decision-iteration," ensuring the correct direction of each step to achieve... It monotonically approximates the minimum, thereby achieving automatic frequency-adjusted convergence.

[0038] Figure 9 To be in a fixed under conditions and Follow The change of , where a) is the real part relative to the 50Ω deviation mapping, a) is the imaginary part deviation mapping, when and Achieving a perfect match at that time. Under the condition of a fixed cavity load, Only by adjustable capacitor and Decision. Therefore, an FPGA-based exhaustive search is employed within the feasible solution domain: fixed... For a given value, make exist The interval is traversed according to the set step size; calculation is performed simultaneously. With ΔX=| |Im{ When both ΔR and ΔX are 0, the adjustable capacitor is moved to the target value found.

[0039] In some feasible embodiments, it also includes: To address sudden mismatches in plasma processes, an intermediate threshold is introduced. (satisfy During operation, if a sudden change in the CCP cavity load causes the plasma glow to extinguish and results in... If so, immediately revert to the pre-matched branch and quickly... Pull back into the controllable zone and achieve restart. Similarly, if during frequency modulation, it is detected that... It also directly jumps to the pre-matching branch, avoiding prolonged high-reflection state. Once any branch reaches... The process is now complete.

[0040] An automatic radio frequency matching system for vacuum coating, applied to the above method, includes: The initialization setup module is used to execute S1; The pre-matching module is used to execute S2; The search module is used to execute S3-S5; Automatic frequency modulation module, used to execute S6.

[0041] The content of the above method embodiments is applicable to this system embodiment. The specific functions implemented in this system embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.

[0042] An automatic radio frequency matching device for vacuum coating: At least one processor; At least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements an automatic radio frequency matching method for vacuum coating as described above.

[0043] The content of the above method embodiments is applicable to the device embodiments. The specific functions implemented by the device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0044] A storage medium storing processor-executable instructions, which, when executed by a processor, are used to implement an automatic radio frequency matching method for vacuum coating as described above.

[0045] The content of the above method embodiments is applicable to this storage medium embodiment. The specific functions implemented in this storage medium embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.

[0046] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A radio frequency automatic matching method for vacuum coating, characterized in that, Application in RF power supply systems for CCP cavity plasma vacuum coating, wherein: The radio frequency power supply system for CCP cavity plasma vacuum coating includes a signal detection circuit, an FPGA power management chip, a parallel adjustable capacitor, and a series adjustable capacitor. The method includes: S1. Initialize all parameters and set the maximum number of search rounds; S2. Call local search to search for parallel and series adjustable capacitors, and judge based on the objective function value after the search and the preset objective value. If the condition is met, the process ends. If the convergence is successful, output the capacitance values ​​of the parallel and series adjustable capacitors in the current round. Otherwise, proceed to the next step. S3. Determine the difference between the current reflection coefficient and the previous reflection coefficient. If the difference is less than the minimum tolerance value, the process ends, indicating progress convergence. Output the parallel adjustable capacitor and series adjustable capacitor for the current round. Otherwise, return to step S2 and start the next round of search.

2. The radio frequency automatic matching method for vacuum coating according to claim 1, characterized in that, Before step S2, the method further includes: The pre-matching point search is invoked to quickly find the target capacitor pair corresponding to the current load within the FPGA, and the parallel adjustable capacitor and the series adjustable capacitor are adjusted to the target position.

3. The radio frequency automatic matching method for vacuum coating according to claim 2, characterized in that, Also includes: When the current search round is greater than the maximum search round and the preset target has not been reached, automatic frequency adjustment is triggered. The power supply operating frequency is slightly adjusted to cross the local minimum and converge to the target reflection coefficient magnitude.

4. The radio frequency automatic matching method for vacuum coating according to claim 2, characterized in that, The local search process specifically includes: Step A1: Save the value of the objective function for the current round and proceed to the next round; Step A2: Obtain the capacitance value, step interval, and adjustable range of the vacuum capacitor currently being searched; Step A3: Calculate the value of the objective function for this round, and search for the target capacitance value in the positive direction in combination with the step interval to obtain the current capacitance value of the adjustable capacitor; Step A4: If the current adjustable capacitor value is within the adjustable range, proceed to step A5; if the current adjustable capacitor value is not within the adjustable range, discard the current capacitor value and proceed to step A7. Step A5: Calculate the objective function value after the forward search. If the objective function value is less than the objective function value before the search, proceed to step A6; otherwise, proceed to step A6. Step A6: Determine the current capacitance value as the capacitance value in step A3, and continue to adjust the capacitance value in the positive direction in combination with the step interval; Step A7: Adjust the capacitor in the negative direction according to the step interval, and calculate the target function value after adjustment. If the target function value is less than the target function value before the search, proceed to step A8. If not, end the search of the current variable and switch variables to search. Step A8: Update the current capacitance value to the capacitance value in step A7, and continue to adjust the capacitance in the negative direction in combination with the step interval.

5. The automatic radio frequency matching method for vacuum coating according to claim 3, characterized in that, The automatic frequency tuning mode specifically includes: Obtain the current frequency and its corresponding reflection coefficient magnitude; The frequency is adjusted along the direction of increasing frequency, and the corresponding reflection coefficient magnitude is calculated based on the preset interval. If the adjusted reflection coefficient magnitude is less than the original reflection coefficient magnitude, the frequency is adjusted further along the direction of increasing frequency; otherwise, the frequency is decreased. The frequency is adjusted along the decreasing direction, using a preset interval, and the corresponding reflection coefficient magnitude is calculated. If the adjusted reflection coefficient magnitude is less than the original magnitude, the frequency is continued to be adjusted in the decreasing direction; otherwise, the frequency is increased. If no decrease in the reflection coefficient modulus is observed after two trials, the frequency adjustment should be terminated.

6. The radio frequency automatic matching method for vacuum coating according to claim 5, characterized in that, This step also includes: If the plasma glow is extinguished and the magnitude of the reflection coefficient corresponding to the current frequency is greater than the intermediate threshold, then return to the pre-matching point search step.

7. A radio frequency automatic matching system for vacuum coating, characterized in that, For performing the automatic radio frequency matching method as described in claim 1, comprising: The initialization setup module is used to execute S1; The search module is used to execute S2; The iterative judgment module is used to execute S3.

8. An automatic radio frequency matching device for vacuum coating, characterized in that, include: At least one processor; At least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements the radio frequency automatic matching method for vacuum coating as described in any one of claims 1-6.

Images