A high-power radio frequency ion source protection system

Abstract

The present invention discloses a high-power radio frequency ion source protection system, which relates to the technical field of radio frequency ion sources. By processing the standing wave signal and the power reflection signal reflecting the discharge state of the radio frequency ion source plasma, and comparing them with the set protection threshold, it is possible to determine the protection signal that needs to be issued under abnormal discharge, and then shut down the radio frequency power output, stop the plasma discharge, and achieve the purpose of protecting the ion source and the power source. At the same time, at the initial moment of plasma establishment, since the impedance matching changes from mismatch to matching, it will cause a sudden change in the standing wave and the reflection signal. The protection system of the present invention is designed with a blind spot to shield the issuance of the protection signal at this moment, thereby avoiding the failure of normal excitation of the plasma. The present invention not only improves the safety of the radio frequency ion source during operation, but also effectively guarantees the efficient and long-term operation of the radio frequency ion source.

Description

Technical Field

[0001] The invention belongs to the technical field of radio frequency ion sources, and in particular relates to a high-power radio frequency ion source protection system. Background Art

[0002] In a high-power RF ion source system, in order to maximize the transmission of RF power from the ion source to the coupling coil, an impedance matching network needs to be designed between the two to adjust the coil plasma equivalent impedance to be consistent with the transmission cable. However, the current design of the matching network still has the following problems: as the RF power increases, the change in plasma concentration will cause a large change in the equivalent impedance, resulting in a significant deterioration in the matching state, causing a surge in reflected power, affecting the performance of the ion source. Continuous high reflected power may even cause damage to the RF power source and ion source-related components. At the initial moment of plasma establishment, this is a dynamic process from nothing to something, and the matching critical value of the previously set matching network has not yet been reached. The matching network is in a mismatched state, so the reflected power will increase sharply. There is a possibility that the reflected power will exceed the set threshold for a short period of time, causing the protection signal to be falsely triggered. This situation will not return to normal until the matching network enters the matching state after the plasma is generated and stabilized. Summary of the Invention

[0003] In response to the above-mentioned problems, the present invention provides a high-power RF ion source protection system. According to the actual situation when the RF ion source is working, accurate monitoring of the reflected power is achieved by setting a reasonable monitoring blind zone time and signal protection threshold, allowing operators to adjust parameters in time to control the impedance matching network status. When the reflected power is too large, it can also issue a timely warning, effectively ensuring the normal, efficient and long-term operation of the RF ion source.

[0004] To achieve the above object, the technical solution adopted by the present invention is:

[0005] A high-power radio frequency ion source protection system consists of a signal interface module, a signal processing module, a controller module, a fiber optic communication module, and a host computer module. Standing wave and reflected signals are input into the protection system through the signal interface module. After voltage division and filtering by the signal processing module, they are input into the controller module. The controller module monitors the voltage amplitude of the input signal in real time and compares it with the protection signal threshold set in the controller module's program. If the voltage amplitude of the input signal is less than the protection signal threshold, the system is normal and no action is taken. If the voltage amplitude of the input signal is greater than or equal to the protection signal threshold, the controller module outputs a protection signal to stop the operation of the radio frequency ion source, thereby preventing damage to the internal components of the ion source.

[0006] The controller module also includes setting a monitoring blind zone time, and shielding the input standing wave signal and reflected signal during the monitoring blind zone time, and not outputting a protection signal;

[0007] The controller module achieves long-distance communication with the host computer module through the optical fiber communication module. The host computer module realizes data visualization through the graphical user interface and provides a user interaction interface, allowing operators to monitor system status, view real-time data and historical records, and configure system settings.

[0008] Furthermore, the controller module includes a setting for monitoring blind time, the purpose of which is to avoid the situation where a protection signal is accidentally output due to a spike pulse generated when the ion source is turned on exceeding the protection signal threshold.

[0009] Furthermore, the circuit board includes a dip switch, and the dip switch is used for quickly debugging parameters and verifying functions on site without going through a host computer.

[0010] Furthermore, when the standing wave signal and the reflected signal reach or exceed the protection signal threshold set in the controller module, the protection system will continue to output the protection signal until a reset signal is input to the protection system.

[0011] Furthermore, all modules included in the protection system are equipped with corresponding indicator lights, and whether the status of the input or output signal corresponding to the module is normal can be judged according to the on and off of the indicator lights, which is convenient for experimenters to debug and repair.

[0012] Furthermore, the standing wave signal and the reflected signal are both parameters for judging the impedance matching state of the RF ion source, wherein the standing wave signal is used to reflect the impedance matching state of the RF ion source before the RF power is loaded, and the reflected signal is used to reflect the impedance matching state of the ion source after the RF power is loaded.

[0013] The beneficial effects of the present invention are:

[0014] The present invention achieves precise monitoring of reflected power by setting a reasonable monitoring blind zone time and protection signal threshold. This allows operators to adjust parameters to control the impedance matching network status in a timely manner, and can also provide timely warnings when the reflected power is excessive, effectively ensuring the normal, efficient and long-term operation of the radio frequency ion source. Data visualization is achieved on the host computer through a graphical user interface, providing a user interaction interface that allows operators to monitor system status, view real-time data and historical records, and configure system settings. While improving operational convenience, it also allows operators to remotely monitor the impedance matching status in real time, improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a structural schematic diagram of a high-power radio frequency ion source protection system of the present invention;

[0016] Figure 2 This is a basic program flow chart of the controller module in the present invention. DETAILED DESCRIPTION

[0017] The present invention will be further described below with reference to the accompanying drawings and examples.

[0018] See also Figure 1 , this embodiment provides a high-power radio frequency ion source protection system. The system is integrated on a circuit board and includes a signal interface module, a signal processing module, a controller module, an optical fiber communication module, and a host computer module. The standing wave signal and the reflected signal are input into the system through the signal interface module, and are input into the controller module after voltage division and filtering by the signal processing module. The controller module monitors the voltage amplitude of the input signal in real time and compares the voltage amplitude of the input signal with the protection signal threshold set in the controller module program. If the voltage amplitude of the input signal is less than the protection signal threshold, it indicates that the system is normal and no processing is performed. If the voltage amplitude of the input signal is greater than or equal to the protection signal threshold, a protection signal is output (pulled down from a high level to a low level) to stop the operation of the radio frequency ion source, thereby avoiding damage to the internal components of the ion source. The controller module also includes setting a monitoring blind zone time, and shielding the input standing wave signal and reflected signal during the monitoring blind zone time, and not outputting a protection signal.

[0019] The controller module communicates with the host computer module over long distances via an optical fiber communication module. The host computer module visualizes data through a graphical user interface, providing a user interface that allows operators to monitor system status, view real-time data and historical records, and configure system settings.

[0020] The input and output signal interfaces in the signal interface module both use 50Ω BNC connectors, which have the characteristics of strong anti-interference ability, stable and reliable connection, and easy use. They can ensure high-quality signal transmission and reduce electromagnetic interference. They are suitable for use in complex industrial environments where radio frequency ion sources are located.

[0021] The signal processing module converts the 0-10V standing wave signal and the reflected signal into a 0-5V voltage identifiable by the MCU ADC interface through high-precision resistor voltage division and filtering, and connects the MCU to perform digital-to-analog conversion.

[0022] Specifically, to ensure accurate voltage division and improve data precision, an operational amplifier follower circuit is added to the traditional resistor voltage divider to isolate the front- and back-stage circuits, minimizing the impact of the back-stage circuit's impedance on the voltage division. Furthermore, to prevent spikes caused by electromagnetic interference from damaging the operational amplifier and ADC interface, a clamping diode is added to the signal processing module to clamp the input signal voltage within the acceptable range of the circuit components, improving circuit stability.

[0023] The controller module uses a low-cost single-chip microcomputer STC8A8K64D4, and performs digital-to-analog conversion on the input analog signal through its built-in ADC module, and compares it with the set protection signal threshold to decide whether to output a protection signal. If the voltage amplitude of the input signal is less than the protection signal threshold, it means that the system is normal and no processing is performed. If the voltage amplitude of the input signal is greater than or equal to the protection signal threshold, a protection signal is output (pulled from a high level to a low level) to stop the operation of the RF ion source to avoid damage to the internal components of the ion source. Once the protection signal is output, it will be maintained until a reset signal is input to the system. When the RF ion source is started, the single-chip microcomputer will receive the start signal and will shield the standing wave signal and reflection signal input during this period according to the set monitoring blind time, and will not output a protection signal.

[0024] The fiber-optic communication module uses low-cost, high-speed fiber-optic transmitters and receivers. The microcontroller converts serial port signals into fiber-optic signals via a serial-to-fiber converter for long-distance communication with a host computer. Fiber-optic communication's advantages, such as wide bandwidth, low transmission loss, and strong resistance to electromagnetic interference, make it ideal for long-distance communication, ensuring reliable communication between the high-power RF ion source protection system and the host computer.

[0025] The host computer module realizes data visualization through a graphical user interface and provides a user interaction interface, allowing operators to monitor system status, view real-time data and historical records, and configure system settings.

[0026] like Figure 2 As shown in the figure, the basic program flow chart of the controller module is given. The first step of the program is to initialize the functions of each pin of the microcontroller according to the hardware circuit of the protection system, such as GPIO, ADC, UART, timer, external interrupt, etc.

[0027] The second step is to update the set monitoring blind zone time and protection signal threshold according to the status of the DIP switch on the circuit board or according to the data set on the host computer;

[0028] The third step is to detect whether there is a start signal input into the system. If so, the rising edge of the start signal is detected, indicating that the start signal has arrived, and the program proceeds to the next step. If not, it returns to the previous step and continues to wait for the start signal;

[0029] The fourth step is to delay the corresponding time according to the set monitoring blind zone time. The monitoring blind zone time is adjustable from 1ms to 10s. In order to ensure the normal operation of the program during the delay time, a timer delay is used here to delay the time.

[0030] The fifth step is to use the ADC inside the microcontroller to convert the input signal into digital form and upload it to the host computer;

[0031] In the sixth step, the converted digital signal is converted into an actual voltage through mathematical conversion and compared with the set protection signal threshold to determine whether it exceeds the protection signal threshold. If it exceeds the protection signal threshold, it indicates that the RF ion source is operating abnormally and the program proceeds to the next step. Otherwise, it indicates that the RF ion source is operating normally and returns to the previous step to continue analog-to-digital conversion of the input signal.

[0032] Step 7: The corresponding pin outputs a protection signal (pulled from high level to low level);

[0033] Step 8: Check whether there is a reset signal input to the system. If so, if the rising edge of the reset signal is detected, proceed to the next step. If not, return to the previous step and continue to output the protection signal.

[0034] Step 9. Cancel the output protection signal and jump to step 1.

[0035] To maximize protection against damage to the RF ion source, the protection system must respond promptly to the start and reset signals. Therefore, the program uses external interrupts to detect the rising edges of the start and reset signals. Furthermore, to ensure the long-term stability of the protection system, a watchdog timer has been added to the program, which is reset continuously during program loops. If the program encounters an abnormality and the watchdog timer expires before being reset, the program automatically resets to its initial state and continues running.

[0036] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-power radio frequency ion source protection system, characterized in that: It includes a signal interface module, a signal processing module, a controller module, an optical fiber communication module, and a host computer module integrated on a circuit board, wherein the standing wave signal and the reflected signal are input into the protection system through the signal interface module as input signals, and are input into the controller module after voltage division and filtering by the signal processing module. The controller module monitors the voltage amplitude of the input signal in real time, and compares the voltage amplitude of the input signal with the protection signal threshold set in the program of the controller module. If the voltage amplitude of the input signal is less than the protection signal threshold, it indicates that the system is normal and no processing is performed; if the voltage amplitude of the input signal is greater than or equal to the protection signal threshold, the controller module outputs a protection signal to stop the operation of the radio frequency ion source; the controller module also includes setting a monitoring blind zone time, and shielding the input standing wave signal and reflected signal during the monitoring blind zone time, and not outputting a protection signal; The controller module achieves long-distance communication with the host computer module through the optical fiber communication module. The host computer module realizes data visualization through the graphical user interface and provides a user interaction interface, allowing operators to monitor system status, view real-time data and historical records, and configure system settings.

2. A high-power radio frequency ion source protection system according to claim 1, characterized in that: The circuit board includes a dip switch, which is used for quickly debugging parameters and verifying functions on site without going through a host computer.

3. A high-power radio frequency ion source protection system according to claim 2, characterized in that: When the standing wave signal and the reflected signal reach or exceed the protection signal threshold set in the controller module, the protection system will continue to output the protection signal until a reset signal is input to the protection system.

4. A high-power radio frequency ion source protection system according to claim 3, characterized in that: All modules included in the protection system are equipped with corresponding indicator lights, and whether the status of the input or output signal corresponding to the module is normal is judged according to the on and off of the indicator lights.

5. A high-power radio frequency ion source protection system according to claim 4, characterized in that: The standing wave signal and the reflected signal are both parameters for judging the impedance matching state of the RF ion source, wherein the standing wave signal is used to reflect the impedance matching state of the RF ion source before the RF power is loaded, and the reflected signal is used to reflect the impedance matching state of the ion source after the RF power is loaded.

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