Matching method for automatic matcher equipment

Abstract

The invention discloses a matching method for automatic matcher equipment, which relates to the technical field of radio frequency impedance matching and is applied to radio frequency impedance matching equipment, and the radio frequency impedance matching equipment is used for connecting a radio frequency output device and a plasma load and controlling the output power of the radio frequency output device to be effectively transmitted to the plasma load. According to the matching method for the automatic matcher equipment, parameter scanning is carried out on two adjustable vacuum capacitors through a two-dimensional optimization scanning algorithm, and target matching parameters are found in advance and stored in a nonvolatile storage module; after the plasma generating device is started, the central processing unit does not need to re-execute full-range scanning, can directly call pre-stored parameters, and controls the capacitor driving mechanism to be quickly adjusted to a target state; even if the initial matching parameters are called in an extreme scene and secondary fine tuning is started, the problem of unstable power caused by scanning lag in an existing scheme is avoided, and the strict requirement of a high-precision process for ignition, namely stability, is met.

Description

Technical Field

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

[0002] In core plasma processes such as semiconductor chip etching, solar cell coating, and aerospace plasma thruster ignition, the radio frequency (RF) source needs to be connected to the plasma load through an automatic RF impedance matching device to eliminate the impedance difference between the RF source and the load. If the impedances of the two are mismatched, the circuit will generate reflected power, which will not only reduce the power transmission efficiency, but may also damage the internal modules of the RF source, shorten the equipment life, or even cause process interruption. Currently, there are two main types of automatic matching methods commonly used in industry, both of which have significant drawbacks in practical applications: The first type is the single-capacitor scanning matching scheme. As an early mainstream technology, its implementation logic is to scan the parameters of only a single adjustable capacitor in the matching network while keeping the parameters of the other capacitor fixed. The optimal matching point is found by detecting the change in reflected power. After the equipment is started, the capacitor parameters are adjusted point by point in a fixed direction, and the reflected power is collected once after each adjustment. After the scan is completed, the parameter with the minimum reflected power is selected as the matching point. However, this scheme ignores the synergistic effect of the two capacitor parameters and is prone to missing the optimal matching point under the combination of two capacitors, resulting in serious insufficient matching accuracy and failing to meet the power stability requirements of high-precision processes. The second type is the fixed-step full-range scanning scheme. To solve the accuracy problem of single-capacitor scanning, this scheme performs a full-range scan on two adjustable capacitors. That is, the parameters of the first capacitor are fixed, and the parameters of the second capacitor are adjusted in fixed steps. Each time the second capacitor is adjusted, the full parameter range of the first capacitor is scanned once until the second capacitor completes the full-range scan. However, firstly, the matching time is too long, and the entire process requires a large number of parameter adjustments and reflection power detection operations, which consumes too much time as a proportion of the total process time, seriously affecting production efficiency. Secondly, the scanning direction is fixed, which makes it easy to miss better matching points in the reverse interval, and there is still a risk of accuracy problems. Therefore, we propose a matching method for automatic matching equipment. Summary of the Invention

[0003] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a matching method for automatic matching devices, solving problems commonly faced by existing automatic matching methods such as insufficient matching accuracy, excessively long matching time, easy entry into matching dead zones, and poor adaptability.

[0004] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: A matching method for an automatic matching device is applied to an RF impedance matching device, which connects an RF output device to a plasma load to achieve effective power transfer from the RF output device to the plasma load. The matching method comprises the following steps: Step 1: Start the radio frequency output device to output the preset power. In the stage before plasma is generated, the radio frequency output device and the plasma load are in an impedance mismatch state, and there is a power reflection phenomenon in the circuit loop. Step 2: Run the optimization scan process to scan and adjust all the capacitance parameters of the two adjustable capacitors (referred to as the first adjustable capacitor and the second adjustable capacitor) included in the matching network of the RF impedance matching device. In the initial state, the parameters of the two adjustable capacitors are adjusted to the minimum parameter value. Step 3: Adjust the current parameters of the second adjustable capacitor according to the preset parameter increment to obtain the adjusted parameters of the second adjustable capacitor; Step 4: Based on the cumulative number of adjustments of the second adjustable capacitor, determine the parameter scanning direction of the first adjustable capacitor, and scan the parameter of the first adjustable capacitor from one limit parameter value to another according to the scanning direction. Step 5: During the parameter scanning process of the first adjustable capacitor, continuously detect the reflected power in the circuit loop and determine whether it has decreased; if the reflected power decreases, immediately stop the scanning, save the parameters of the two adjustable capacitors at this time as the target matching parameters, and exit the optimization scanning process; if the reflected power does not decrease, return to step 3 and repeat the parameter adjustment and scanning operation. Step 6: After plasma generation, the radio frequency impedance matching device calls the saved target matching parameters to quickly achieve impedance matching between the radio frequency output device and the plasma load, so that almost all the power output by the radio frequency output device is transferred to the plasma load, and the matching process does not enter the dead zone of the matching point.

[0005] Preferably, the preset power of the RF output device is determined according to the plasma process requirements. The reflected power in the circuit loop is collected in real time by the power detection component built into the RF impedance matching device. The power detection component is connected in series between the RF output device and the matching network to continuously capture the power reflection data in the loop.

[0006] Preferably, the matching network has an L-shaped structure, and the optimization scanning process is executed by the central control unit of the RF impedance matching device; the first and second adjustable capacitors are both vacuum capacitors, and their minimum parameter values ​​correspond to the minimum capacitance range that matches the design requirements of the matching network. The specific values ​​are determined by the design scheme of the matching network.

[0007] Preferably, the preset parameter increment is a fixed value, which can be set according to the matching accuracy requirements, typically 5%. After each parameter adjustment of the second adjustable capacitor, a stable time is maintained to meet the power detection requirements, ensuring that the power detection component collects stable reflected power data. The parameter adjustment of the second adjustable capacitor is achieved by the central control unit sending control commands to the matching drive mechanism. The drive mechanism changes the distance between the capacitor plates through mechanical transmission, thereby adjusting the capacitor capacity. The parameter can be adjusted to the maximum parameter value, and the maximum capacity range corresponding to this parameter value is adapted to the matching network design requirements.

[0008] Preferably, the cumulative number of adjustments for the second adjustable capacitor is calculated starting from the initial minimum parameter value, and each parameter adjustment operation in step 3 is counted as one adjustment. When the cumulative number of adjustments is odd, the scanning direction of the first adjustable capacitor is from the minimum parameter value to the maximum parameter value. When the cumulative number of adjustments is even, the scanning direction is from the maximum parameter value to the minimum parameter value. The maximum upper limit of the cumulative number of adjustments is determined by the preset parameter increment and the maximum parameter value, ensuring that the second adjustable capacitor can be adjusted from the minimum parameter value to the maximum parameter value.

[0009] Preferably, real-time detection of reflected power is achieved through a power separation component used to separate the forward power and reflected power of the separation circuit. This component transmits the separated reflected power data to the central control unit. The criterion for determining a decrease in reflected power is that the currently detected reflected power value is less than the previously detected reflected power value. The detection time interval is adapted to the parameter adjustment accuracy of the first adjustable capacitor to ensure accurate capture of changes in reflected power.

[0010] Preferably, the storage medium for the target matching parameters is a non-volatile storage component equipped with the central control unit. This storage component can retain the saved parameter data without loss after the RF impedance matching device is powered off. The accuracy of the saved parameter data is adapted to the matching requirements, specifically including the real-time parameter values ​​of the first adjustable capacitor and the second adjustable capacitor.

[0011] Preferably, if the parameters of the second adjustable capacitor have been adjusted to the maximum parameter value, and no decrease in reflected power is detected after completing the corresponding scan of the first adjustable capacitor, then the repeated operation of steps 3 to 5 is stopped, the maximum parameter values ​​of the two adjustable capacitors are saved as the initial matching parameters, and the optimization scan process is exited; after plasma generation, the RF impedance matching device starts a secondary fine-tuning operation based on the initial matching parameters. The parameter increment of the fine-tuning is less than the preset parameter increment in step 3, and the scanning rate is adapted to the fine-tuning accuracy requirements until the reflected power drops below the preset minimum threshold, and the secondary fine-tuning process also does not enter the matching point dead zone.

[0012] Preferably, the criterion for determining that almost all power has been transmitted is that the reflected power drops below a preset percentage of the output power of the RF output device, typically 5%. The RF impedance matching equipment is suitable for plasma process-related industries, including the semiconductor industry, the solar energy industry, or the aerospace propulsion industry. The plasma load maintains a stable plasma state by receiving the power output from the RF output device, ensuring the smooth execution of the corresponding process.

[0013] Preferably, the method achieves the technical effect of not entering the dead zone of the matching point during the matching process by comprehensively scanning all parameters of the two adjustable capacitors and combining the reverse scanning logic that determines the scanning direction of the first adjustable capacitor based on the number of adjustments of the second adjustable capacitor. At the same time, it shortens the impedance matching time, improves the impedance matching accuracy, and solves the problems of low matching efficiency, insufficient matching accuracy, and easy entry into the dead zone of the matching point in existing automatic matching equipment.

[0014] (III) Beneficial Effects 1. Before plasma is generated, a two-dimensional optimization scanning algorithm is used to scan the parameters of the two adjustable vacuum capacitors, find the target matching parameters in advance, and store them in a non-volatile storage module. When the plasma generator is started, the central processing unit does not need to re-execute the full-range scan, but can directly call the pre-stored parameters to control the capacitor drive mechanism to quickly adjust to the target state. Even in extreme scenarios, the initial matching parameters are called and secondary fine-tuning is started, avoiding the power instability problem caused by scanning lag in existing solutions. This meets the stringent requirements of high-precision processes for stability upon ignition. Secondly, dual adjustable capacitors are used for collaborative scanning, rather than single capacitor adjustment, covering all possible combinations of capacitor parameters. Moreover, the reverse scanning logic of the first adjustable capacitor ensures that after each round of adjustment of the second adjustable capacitor, the first adjustable capacitor scans from the minimum parameter value to the maximum parameter value when the number of adjustments of the second adjustable capacitor is odd, and from the maximum parameter value to the minimum parameter value when the number of adjustments is even. This ensures that after each round of adjustment of the second adjustable capacitor, the first adjustable capacitor can cover the potential matching points in the reverse interval. 2. The RF power adaptation range covers 100W to 10000W, and the scan rate can be dynamically adjusted according to the power. The scan rate corresponds to 3% / ms to 5% / ms for the 100W to 1000W power range, and 1% / ms to 3% / ms for the 1000W to 10000W power range, meeting different power requirements such as low-power coating and high-power etching. Moreover, the impedance adjustment range of the L-shaped matching network is 0.5Ω to 49Ω, which can adapt to the drastic impedance changes before and after plasma generation. In addition to the above, the solution is not bound to specific process parameters. 100 sets of matching parameters for different processes can be saved through the storage module, and one-click switching can be made for scenarios such as semiconductor etching, solar cell coating, and aerospace propulsion ignition. 3. Employing a dual-storage design of EEPROM and RAM, the EEPROM can retain parameters for over 10 years after a power outage, while the RAM improves the read / write speed during scanning. After a power outage and restart, the central processing unit automatically reads the most recently saved matching parameters from the EEPROM, skipping the pre-matching process and directly entering the working state. In continuous operation testing on the semiconductor production line, the equipment is powered on and off once daily, and after restarting, there is no need to rescan, allowing for rapid restoration of the matching state. Simultaneously, the adjustable vacuum capacitor uses a high-voltage, low-loss vacuum medium with a temperature coefficient controlled within ±50ppm / ℃. Even under ambient temperature fluctuations ranging from -20℃ to 80℃, the capacitance stability still meets the matching requirements, ensuring long-term stable operation of the equipment. Attached Figure Description

[0015] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0016] Figure 1 This is a circuit architecture diagram in an embodiment of the present invention; Figure 2 This is a flowchart illustrating the overall process in an embodiment of the present invention. Detailed Implementation

[0017] This application provides a matching method for automatic matching devices, which solves the problems commonly faced by existing automatic matching methods, such as insufficient matching accuracy, excessive matching time, easy entry into matching dead zones, and poor adaptability.

[0018] Example: The technical solution in this application aims to address the problems commonly faced by existing automatic matching methods, such as insufficient matching accuracy, excessively long matching time, easy entry into matching dead zones, and poor adaptability. The overall approach is as follows: To address the problems existing in the prior art, the present invention provides a matching method for an automatic matcher device, the content of which is as follows: The application is for radio frequency impedance matching equipment that connects radio frequency output devices and plasma loads. The core objective is to achieve almost full power transmission and avoid dead zones at the matching point. The first step is to start up and confirm the initial state. Start the radio frequency output device and output the preset power. This power needs to be set according to the plasma process requirements, ranging from 100 watts to 10,000 watts. At this time, the plasma has not been generated. The radio frequency output device and the plasma load are in a mismatched state due to the difference in impedance characteristics, and power reflection naturally occurs in the circuit. The second step is to start the optimization scan and set the initial parameters. The central control unit runs the optimization scan process to scan and adjust all the capacitor parameters of the two adjustable capacitors in the matching network without omission. In the initial state, the parameters of the two adjustable capacitors must be adjusted to the minimum parameter value to lay the foundation for the subsequent full-range scan. The third step is to adjust the second adjustable capacitor incrementally. The current parameter of the second adjustable capacitor is adjusted by a fixed amount according to the preset parameter increment to obtain the adjusted parameter. The increment needs to take into account both efficiency and accuracy, and the typical value is 5%. The fourth step is to determine and execute the scanning direction of the first adjustable capacitor. The scanning direction is determined based on the cumulative number of adjustments of the second adjustable capacitor. Each time the adjustment in the third step is executed, it is counted as one time. When the number of times is odd, the scanning direction is from the minimum parameter value to the maximum parameter value. When the number of times is even, the scanning direction is from the maximum parameter value to the minimum parameter value, ensuring that the parameter coverage is not repeated. The fifth step is to detect and save the reflected power. During the first adjustable capacitor scan, the power detection component continuously detects the reflected power and transmits it to the central control unit. The central control unit judges in real time whether the power has decreased. If it has decreased, the scan is stopped immediately, the parameters of the two adjustable capacitors are saved as target matching parameters to the non-volatile storage component and the optimization scan process is exited. If it has not decreased, the operation is repeated in the third step. The sixth step is rapid matching after plasma generation. After plasma generation, the central control unit immediately calls the saved target matching parameters and controls the drive mechanism to quickly adjust the two adjustable capacitors to the parameters, so as to achieve rapid impedance matching, ensuring that almost all power is transmitted and that the matching point dead zone is not entered.

[0019] The RF output device provides stable RF power, with an output frequency band adapted to the high-frequency range commonly used in plasma processes. The plasma load consists of a load cavity, electrode assembly, and gas introduction structure, which ionizes the process gas to form plasma after receiving power. The matching network is the core of impedance adjustment, working in conjunction with two adjustable capacitors to adapt the impedance. The central control unit coordinates process control, data processing, and logic judgment. The power detection component captures reflected power data. The non-volatile storage component stores the matching parameters long-term. The drive mechanism realizes the mechanical adjustment of the capacitor parameters. The two adjustable capacitors change the equivalent impedance of the matching network by changing their capacitance values.

[0020] The acquisition of preset power and reflected power of the RF output device includes the basis for determining the preset power, the installation position and function of the power detection component, and the data transmission requirements. The relevant components used include the RF output device, the power detection component, and the central control unit. The power detection component is composed of a directional coupler and a logarithmic detector.

[0021] The preset power is determined based on the specific requirements of the plasma process. Different processes correspond to different power: semiconductor chip etching processes require high power to ensure etching rate, and 2000 watts are commonly used; solar cell coating processes require balanced power to ensure film uniformity, and 500 watts are commonly used; aerospace plasma thruster ignition processes require stable power to ensure successful ignition, and 1000 watts are commonly used, ensuring that the energy supply is precisely matched with the process requirements.

[0022] The power detection component is a built-in structure and must be connected in series in the signal transmission path between the RF output device and the matching network. This installation position can minimize the interference of signal transmission loss on the detection results. The installation interface must be compatible with the connection specifications of the RF output device and the matching network to avoid additional adaptation problems. The core function of the power detection component is to collect power reflection data in the loop in real time, providing a continuous and accurate data source for subsequent reflection power judgment. Its working principle is to separate the forward power in the loop, i.e., the output power of the RF source, and the reflected power, through a directional coupler, and then convert the reflected power signal into a voltage signal that can be recognized by the central control unit through a logarithmic detector, ensuring real-time performance and accuracy.

[0023] Matching network type, optimization scan execution entity, adjustable capacitor type and minimum capacity, including the structure and composition of the matching network, the execution entity and function of the optimization scan, and the type and minimum capacity requirements of the adjustable capacitor. The relevant content used includes L-type matching network, central control unit and vacuum dielectric adjustable capacitor. The L-type matching network consists of a series inductor and two adjustable capacitors.

[0024] The matching network adopts an L-shaped structure, and the series inductor is a high-frequency ferrite core inductor. Its core function is to assist in adjusting the impedance matching range. It works in conjunction with two adjustable capacitors to achieve a wide-band impedance adaptation from 0.5 ohms to 49 ohms, meeting the impedance variation requirements of most plasma loads.

[0025] The central control unit of the RF impedance matching equipment is the main body that executes the optimization scanning process. This unit needs to use a high-performance microcontroller or FPGA chip, with a multi-channel ADC interface for receiving power detection data and a PWM output interface for issuing drive commands. It supports fast logic operations and command issuance, with a response time of no more than 100 microseconds to ensure the real-time performance of process control. Its core function is to coordinate all key operations such as capacitor parameter adjustment, data acquisition, and logic judgment by issuing commands.

[0026] Both the first and second adjustable capacitors are vacuum dielectric capacitors. This type of capacitor features high voltage resistance, low loss, and high capacitance stability. The dielectric loss tangent is less than 0.0005, and the temperature coefficient is ±50ppm / ℃. It is suitable for the high-frequency output band of RF output devices, typically 13.56MHz. The minimum capacitance range corresponding to its minimum parameter value needs to be adapted to the matching network design requirements. The specific values ​​are determined by the matching network design scheme, with a typical range of 1 picofarad to 10 picofarads, ensuring that the capacitor parameter adjustment can cover the impedance adjustment range required by the process.

[0027] The preset parameter increment, stabilization time, capacitor parameter adjustment implementation method, and maximum capacity are included. This includes the setting principles and typical values ​​of the preset parameter increment, the role and value of the stabilization time, the mechanical implementation process of parameter adjustment, and the adaptation requirements of the maximum capacity. The relevant components used include the central control unit, drive mechanism, second adjustable capacitor, and power detection component. The drive mechanism consists of a stepper motor and transmission gears, and the second adjustable capacitor is a vacuum dielectric type.

[0028] The preset parameter increment is a fixed value. The setting principle is to balance matching efficiency and accuracy. If the increment is too large, the optimal matching point may be missed. If the increment is too small, the time consumption will be too long. The typical value is 5%. Users can adjust it flexibly according to the accuracy requirements of the actual process.

[0029] After each adjustment of the parameters of the second adjustable capacitor, a stable time is required to meet the power detection requirements. This time is used to eliminate transient signal interference after the capacitor parameter adjustment and to ensure that the power detection component collects stable reflected power data. The typical value is 0.5 seconds, which can be increased or decreased appropriately according to the adjustment range of the capacitor parameters.

[0030] The parameter adjustment of the second adjustable capacitor is achieved through a mechanical structure: the central control unit sends control commands to the matching drive mechanism according to the scanning logic. The step angle of the stepper motor is no more than 1.8°. The transmission ratio of the transmission gear is set according to the accuracy requirements of the capacitor plate spacing adjustment to ensure that the parameter adjustment accuracy reaches 0.1%. After receiving the command, the stepper motor drives the capacitor plates to move through the transmission gear, thereby changing the plate spacing and adjusting the capacitor capacity.

[0031] The parameters of the second adjustable capacitor can be adjusted to the maximum parameter value. The maximum capacitance range corresponding to this parameter value needs to be adapted to the network design requirements. The typical range is 10 picofarads to 50 picofarads. This ensures that after matching with the minimum capacitance, the capacitance adjustment can cover the impedance range required by the process.

[0032] The statistical starting point for the cumulative number of adjustments, the switching logic for the scanning direction, and the upper limit of the maximum number of adjustments, including the statistical rules for the cumulative number of adjustments, the switching conditions and response requirements for the scanning direction, and the calculation basis for the upper limit of the maximum number of adjustments, are all included. The relevant components used include the central control unit, the first adjustable capacitor, and the drive mechanism. The central control unit has a built-in counting module.

[0033] The cumulative number of adjustments to the second adjustable capacitor starts from the initial minimum parameter value. In the initial state, the value of the counting module is 0. Each time the parameter adjustment operation in the third step is successfully executed, the counting module automatically increments by 1 to ensure accurate statistics.

[0034] The switching logic for the scanning direction is as follows: when the cumulative number of adjustments is odd, the central control unit sends a forward scanning command to the drive mechanism, and the first adjustable capacitor scans from the minimum parameter value to the maximum parameter value; when the cumulative number of adjustments is even, a reverse scanning command is sent, and the first adjustable capacitor scans from the maximum parameter value to the minimum parameter value. The switching response time does not exceed 100 microseconds, ensuring a continuous scanning process.

[0035] The maximum number of cumulative adjustments is determined by the preset parameter increment and the maximum parameter value. The calculation formula is that the maximum limit is equal to the maximum parameter value minus the initial parameter value and divided by the preset parameter increment. If the preset parameter increment is 5%, the maximum parameter value is 100%, and the initial parameter value is 0%, then the maximum limit is 20 times, ensuring that the second adjustable capacitor can be completely adjusted from the minimum parameter value to the maximum parameter value, achieving full-range scanning without omissions.

[0036] The reflection power detection component, judgment criteria, and detection time interval include the implementation components and performance requirements of reflection power detection, the judgment logic for reflection power reduction, and the adaptation principle of the detection time interval. The relevant contents used include a power separation component, a central control unit, a first adjustable capacitor, and a power detection component. The power separation component is a directional coupler, and the central control unit has a built-in data cache module.

[0037] Real-time detection of reflected power is achieved through a power separation component, which is a directional coupler with a coupling degree of 20dB and an isolation degree of no less than 30dB. Its core function is to accurately separate the forward power and reflected power in the circuit, avoid mutual interference between the two power signals, and ensure the purity and accuracy of the reflected power data. The separated reflected power data is transmitted to the central control unit through signal lines.

[0038] The criterion for determining a decrease in reflected power is that the currently detected reflected power value is less than the previously detected reflected power value. The central control unit has a built-in data cache module, which is specifically used to store the previously detected reflected power data. After receiving the current detection data, it immediately starts the value comparison calculation. If the current value is less than the cached value, it is determined that the reflected power has decreased; otherwise, it is determined that it has not decreased. The determination process takes no more than 10 microseconds.

[0039] The detection time interval is adapted to the parameter adjustment accuracy of the first adjustable capacitor. The principle is to perform a reflection power detection every time the parameter with the minimum accuracy is adjusted to ensure that the subtle changes in reflection power can be accurately captured. If the parameter adjustment accuracy of the first adjustable capacitor is 1%, the detection time interval is set to 200 microseconds, which matches the time required for 1% parameter adjustment, so as to realize the synchronous linkage between parameter adjustment and detection.

[0040] The storage medium, storage accuracy, and storage process for target matching parameters include the type and performance requirements of the storage medium, the standard for storage accuracy, and the complete storage process. The relevant components used include non-volatile storage components, a central control unit, and two adjustable capacitors. The non-volatile storage component is an EEPROM chip.

[0041] The target matching parameters are stored in a non-volatile storage component equipped in the central control unit. This component uses an EEPROM chip, and the data retention time after power failure is no less than 10 years, ensuring that the matching parameters are stored effectively for a long time and will not be lost even if the device is powered off and restarted.

[0042] The accuracy of the saved parameter data must be adapted to the matching requirements, with a standard of 0.1% precision, completely consistent with the actual adjusted parameter values, without any loss of precision, ensuring accurate reproduction of the matching state during subsequent calls. The complete saving process is as follows: After the central control unit determines that the reflected power has decreased, it immediately initiates a parameter reading operation to obtain the real-time parameter values ​​of the first and second adjustable capacitors; according to the standard of 0.1% precision, the two parameter values ​​are written to the designated address of the EEPROM chip, with a pre-allocated dedicated storage area to avoid data confusion; after the writing is completed, the EEPROM chip sends a confirmation signal of successful data writing to the central control unit; after receiving the confirmation signal, the central control unit determines that the parameter saving is complete, and then executes the operation of exiting the optimization scan process to ensure that the data is saved without any loss.

[0043] Supplementary handling scheme for situations where reduced reflected power is not detected in special scenarios includes the triggering conditions, processing flow, parameter settings for secondary fine-tuning, and effect requirements for special scenarios. The relevant components used include the central control unit, non-volatile storage components, two adjustable capacitors, drive mechanism, and power detection components.

[0044] The triggering condition for a special scenario is: the parameter of the second adjustable capacitor has been adjusted to 100%, which is the maximum parameter value, and after the corresponding scan of the first adjustable capacitor is completed, the power detection component still does not detect a decrease in reflected power. At this time, a special processing procedure needs to be started to avoid the algorithm from getting stuck in an infinite loop.

[0045] The processing flow consists of two steps: The first step is to stop the repetitive operation and save the initial matching parameters. The central control unit stops repeating the operations from the third to the fifth step, takes the maximum parameter value of the two adjustable capacitors as the initial matching parameters, writes them to the non-volatile storage component according to the saving procedure, and then exits the optimization scanning process. The second step is the secondary fine-tuning after plasma generation. After plasma generation, the central control unit calls the saved initial matching parameters and starts the secondary fine-tuning operation. The parameter increment of the fine-tuning must be less than the preset parameter increment in the third step, with a typical value of 1%. The scanning rate is reduced to 0.5% / millisecond to improve the fine-tuning accuracy. During the fine-tuning process, the power detection component continuously detects the reflected power until it drops below the preset minimum threshold. The fine-tuning process must also meet the requirement of not entering the matching point dead zone.

[0046] The preset minimum threshold is set according to the process requirements for power transmission efficiency. The typical value is 5% of the output power of the RF output device to ensure that the power transmission efficiency meets the standard.

[0047] The criteria for determining near-complete power transmission, industry compatibility, and working principle of the plasma load, including the setting principles and typical values ​​of the criteria, industry compatibility conditions of the equipment, and the structure and function of the plasma load, are discussed. The relevant content used includes radio frequency impedance matching equipment, radio frequency output devices, and the plasma load. The plasma load consists of a load cavity, electrode components, and a gas introduction structure.

[0048] The criterion for determining that the power is basically fully transmitted is that the reflected power drops below a preset percentage of the output power of the RF output device. The setting principle is to meet the power transmission efficiency requirements of different industry processes. For high-precision processes in the semiconductor industry, it can be set to 5%, while for ordinary processes, it can be appropriately relaxed but not exceeding 10%. The typical preset percentage is 5%, ensuring that the power transmission efficiency is not less than 95%.

[0049] RF impedance matching equipment is suitable for plasma process-related industries, including the semiconductor, solar energy, and aerospace industries. Its industry compatibility conditions are as follows: operating temperature range covers -20℃ to 80℃, adapting to different workshops or working environments in various industries; output power compatibility range covers 100 watts to 10,000 watts, meeting the energy requirements of different industry processes; and interface specifications are compatible with mainstream RF output devices and plasma loads, requiring no additional adaptation or modification.

[0050] The plasma load consists of a load cavity, an electrode assembly, and a gas introduction structure. Its working principle is as follows: process gases, such as argon for semiconductor etching and nitrogen for solar coating, are introduced into the load cavity through the gas introduction structure. The electrode assembly receives the power output from the radio frequency output device and generates a high-frequency electric field, which ionizes the process gas in the cavity to form plasma. At the same time, the plasma state is stably maintained to ensure the smooth execution of the corresponding process.

[0051] The method's effects and implementation logic include the principles behind its three main effects: no dead zone at matching points, reduced matching time, and improved matching accuracy. It also addresses the shortcomings of existing technologies. The relevant components include two adjustable capacitors, a central control unit, a pre-matching process, a power detection component, and reverse scanning logic. The logic for eliminating dead zones at matching points is as follows: a comprehensive scan of all parameters of the two adjustable capacitors covers all potential matching points. Simultaneously, reverse scanning logic determines the scanning direction of the first adjustable capacitor based on the number of adjustments made to the second adjustable capacitor. This avoids repeatedly scanning the same parameter range, ensuring that no optimal matching point is missed, thus fundamentally eliminating the occurrence of dead zones at matching points.

[0052] The logic for shortening the matching time is as follows: an innovative pre-matching process is adopted before plasma generation. The target matching parameters are found and saved in advance before plasma is generated. After plasma generation, there is no need to re-execute the full range scan. The pre-stored parameters can be directly called to quickly achieve matching, which shortens the matching time by 10 to 100 times compared with the existing solution of scanning and matching after plasma generation.

[0053] The logic for improving matching accuracy is as follows: multiple technical designs work together to ensure accuracy, including a high-precision power detection component with a detection accuracy of ±0.5dB, a real-time data comparison and judgment mechanism, accurate parameter storage with an accuracy of 0.1%, and secondary fine-tuning optimization increment of 1%, to ensure that the reflected power can be stably controlled below the preset ratio and the power transmission efficiency is not less than 95%.

[0054] The above-mentioned synergistic effect effectively solves the core defects of existing automatic matching equipment, such as low matching efficiency, insufficient matching accuracy, and easy entry into the matching point dead zone.

[0055] Finally, it should be noted that the above embodiments are merely examples for clearly illustrating the present invention and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A matching method for an automatic matching device, applied to a radio frequency impedance matching device, wherein the radio frequency impedance matching device is used to connect a radio frequency output device and a plasma load, and controls the effective transmission of the output power of the radio frequency output device to the plasma load, characterized in that, The matching method involves the following steps: The radio frequency output device is activated and outputs power according to the preset power. In the stage before plasma is generated, the radio frequency output device and the plasma load are in an impedance mismatch state. Run the optimization scanning process to scan and adjust all capacitor parameters of the first and second adjustable capacitors included in the matching network of the RF impedance matching device. In the initial state, the parameters of the two adjustable capacitors are adjusted to the minimum parameter value. The current parameters of the second adjustable capacitor are adjusted incrementally to obtain the adjusted parameters of the second adjustable capacitor. Based on the cumulative number of adjustments to the second adjustable capacitor, the parameter scanning direction of the first adjustable capacitor is adjusted, and the parameter of the first adjustable capacitor is scanned from one limit parameter value to another according to the scanning direction. During the parameter scanning process of the first adjustable capacitor, the reflected power in the circuit loop is continuously detected and it is determined whether it has decreased. If the reflected power decreases, the scanning is stopped, the parameters of the two adjustable capacitors at this time are saved as target matching parameters, and the optimization scanning process is exited. Otherwise, the adjustment of the parameters of the second adjustable capacitor is returned, and the parameter adjustment and scanning operation is repeated. After plasma is generated, the radio frequency impedance matching device calls the saved target matching parameters to perform impedance matching between the radio frequency output device and the plasma load, so that the power output by the radio frequency output device is transmitted to the plasma load, and the matching process does not enter the dead zone of the matching point.

2. The matching method for an automatic matching device according to claim 1, characterized in that, The preset power of the RF output device is adjusted according to the plasma process. The reflected power in the circuit loop is collected in real time by the power detection component built into the RF impedance matching device. This power detection component is connected in series between the RF output device and the matching network to continuously capture the power reflection data in the loop.

3. The matching method for an automatic matching device according to claim 1, characterized in that, The matching network has an L-shaped structure, and the optimization scanning process is executed by the central control unit of the RF impedance matching device. Both the first and second adjustable capacitors are vacuum capacitors, and their minimum parameter values ​​correspond to the minimum capacitance range of the matching network.

4. The matching method for an automatic matcher device according to claim 1, characterized in that, The preset parameter increment is a fixed value, which is set according to the matching accuracy; After each adjustment of the parameters of the second adjustable capacitor, a stabilization period is maintained, and then stable reflected power data is collected through the power detection component. The parameter adjustment of the second adjustable capacitor is completed by sending control commands to the matching drive mechanism through the central control unit. The drive mechanism changes the distance between the capacitor plates through mechanical transmission to adjust the capacitor capacity. Its parameter can be adjusted to the maximum parameter value, and the maximum capacity range corresponding to this parameter value is compatible with the matching network.

5. The matching method for an automatic matching device according to claim 1, characterized in that, The cumulative number of adjustments for the second adjustable capacitor is counted starting from the initial minimum parameter value. Each time the parameter adjustment operation of the second adjustable capacitor is performed, it is counted as one adjustment. When the cumulative number of adjustments is odd, the scanning direction of the first adjustable capacitor is from the minimum parameter value to the maximum parameter value; when the cumulative number of adjustments is even, the scanning direction is from the maximum parameter value to the minimum parameter value. The maximum number of cumulative adjustments is obtained from the preset parameter increment and the maximum parameter value, and the second adjustable capacitor is adjusted from the minimum parameter value to the maximum parameter value.

6. The matching method for an automatic matcher device according to claim 1, characterized in that, The reflected power is detected in real time by a power separation component used to separate the positive power and reflected power of the separation circuit. This component transmits the separated reflected power data to the central control unit. The criterion for determining a decrease in reflected power is that the currently detected reflected power value is less than the previously detected reflected power value. The detection time interval is relative to the parameter adjustment accuracy of the first adjustable capacitor to capture changes in reflected power.

7. The matching method for an automatic matcher device according to claim 1, characterized in that, The target matching parameters are stored in a non-volatile storage component equipped with the central control unit. This storage component can retain the saved parameter data without loss after the RF impedance matching device is powered off.

8. The matching method for an automatic matcher device according to claim 1, characterized in that, If the parameters of the second adjustable capacitor have been adjusted to the maximum parameter value, and no reduction in reflected power is detected after completing the corresponding scan of the first adjustable capacitor, then the repeated operation is stopped, the maximum parameter values ​​of the two adjustable capacitors are saved as the initial matching parameters, and the optimization scan process is exited. After plasma is generated, the radio frequency impedance matching device initiates a secondary fine-tuning operation based on the initial matching parameters. The parameter increment of the fine-tuning is less than the preset parameter increment until the reflected power drops below the preset minimum threshold. The secondary fine-tuning process also does not enter the matching point dead zone.

9. The matching method for an automatic matching device according to claim 1, characterized in that, The criterion for determining that almost all power is transmitted is that the reflected power drops below a preset percentage of the output power of the RF output device. Radio frequency impedance matching equipment is suitable for industries related to plasma processes, including the semiconductor industry, the solar energy industry, or the aerospace propulsion industry; The plasma load maintains a stable plasma state by receiving power from the radio frequency output device.

10. The matching method for an automatic matcher device according to claim 1, characterized in that, The method involves a comprehensive scan of all parameters of the two adjustable capacitors, combined with a reverse scan logic that determines the scan direction of the first adjustable capacitor based on the number of adjustments made to the second adjustable capacitor.

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