A radio frequency (RF) matching device automatic detection apparatus and method

Abstract

The present application relates to a kind of radio frequency matchers automatic detection equipment and method, belong to semiconductor equipment detection technical field;The equipment radio frequency matchers automatic detection, matching range detection circuit is connected radio frequency switch, radio frequency power supply, probe and radio frequency matchers by radio frequency coaxial cable or radio frequency connector;Analog load module includes first impedance tuning module and second impedance tuning module, first impedance tuning module and second impedance tuning module all include by stepping motor regulated capacitance vacuum adjustable capacitor and inductance;Absorbing load module is connected probe and radio frequency switch by radio frequency coaxial cable or radio frequency connector.The present application detection method includes self-calibration stage compensation absorbing load impedance excursion, matching range test in adjusting four groups of capacitor extreme combination and gathering impedance data, matching time and detection standing wave ratio and stability test.The present application replaces process chamber and realizes full-automatic detection, solves the problem that dynamic change cannot be simulated impedance.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor equipment testing technology, specifically relating to an automatic testing device and method for radio frequency matching devices. Background Technology

[0002] In semiconductor ICP or CCP process equipment, the RF matching unit is a core component for adjusting the impedance matching between the RF power supply and the process chamber. Impedance mismatch can lead to reduced RF power transmission efficiency, plasma excitation failure, and even damage to the equipment due to excessive reflected power. Therefore, the performance of the RF matching unit directly determines the stability and yield of semiconductor manufacturing equipment. Currently, the testing of RF matching devices mainly relies on two techniques: manual testing combined with process chamber and fixed load simulation. Technicians manually adjust the matching device parameters, introduce different gases into the process chamber, adjust the pressure, and observe the plasma ignition state. However, this testing method is time-consuming, requiring several hours for a single test, and cannot simulate the ignition stage. The chamber impedance undergoes a dramatic transition from high to low impedance within nanoseconds to microseconds, making the test highly susceptible to the state of the process chamber, resulting in unreproducible test results. The fixed load simulation method uses a 50Ω fixed impedance load to replace the process chamber and measures S-parameters using a network analyzer. However, this method can only detect the static impedance matching range and cannot verify the scenario where the load impedance drops sharply from the kiloohm level to the hundred ohm level during plasma ignition, nor can it verify the continuous impedance fluctuations caused by changes in process conditions such as process gas ratios, nor can it monitor the response speed and stability of the matching device under dynamic loads. Researchers have proposed simulating the load using a parallel LC circuit, but this method still relies on mechanically adjusting the capacitor, with adjustment delays reaching milliseconds, differing from the actual ignition time of the process chamber by a factor of hundreds.

[0003] Therefore, there is an urgent need for an automatic testing device and method for radio frequency matching devices. Summary of the Invention

[0004] Based on the problems existing in the prior art, the present invention provides an automatic testing device and method for radio frequency matching devices to solve the problems that the prior art cannot automatically simulate the dynamic impedance characteristics of process chambers, does not support multi-port testing, and does not have self-calibration function, resulting in incomplete performance evaluation and low testing efficiency of radio frequency matching devices.

[0005] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution:

[0006] An automatic RF matching circuit testing device includes a matching range detection circuit, an analog load module, an absorption load module, and a control module.

[0007] The matching range detection circuit includes an RF power supply, a first probe, an RF matching unit, a second probe, a third probe, RF switches S1 and S2. The RF power supply is connected to the first probe via an RF coaxial cable. The first probe is connected to the input terminal of the RF matching unit. The first output terminal of the RF matching unit is connected to the second probe, and the second output terminal of the RF matching unit is connected to the third probe. The second probe is connected to the common terminal of RF switch S2, and the third probe is connected to the common terminal of RF switch S1. The three RF switches S1, S2, and S3 are controlled by a control module. The matching range detection circuit is used to establish an RF signal path and acquire impedance parameters.

[0008] The simulated load module includes a first impedance tuning module and a second impedance tuning module. Both the first and second impedance tuning modules include a vacuum adjustable capacitor and an inductor. The first impedance tuning module includes a vacuum adjustable capacitor C1 and C2 connected in parallel and a grounded inductor L1. The second impedance tuning module includes a vacuum adjustable capacitor C3 and C4 connected in parallel and a grounded inductor L2. The simulated load module is used to dynamically simulate the impedance characteristics of the process chamber.

[0009] The absorption load module includes a probe and an absorption load DL; the probe is connected to the absorption load DL, and the absorption load DL is grounded; the absorption load module is used to provide a reference impedance and achieve self-calibration.

[0010] The control module is used to control the on / off state of the RF switch, adjust the capacitance value, and monitor probe data.

[0011] Furthermore, the vacuum adjustable capacitor in the simulated load module has a capacitance range of 0-200pF, and the adjustment method is a stepper motor, relay or voltage-controlled diode.

[0012] Furthermore, the control module includes a microcontroller, a capacitor adjustment element, and a communication control circuit for adjusting the capacitor element.

[0013] Furthermore, the capacitors of the simulated load module are interconnected via metal connecting strips, and the inductors are grounded.

[0014] Furthermore, the Load terminal of the RF switch S3 is connected to an analog load module, and the Com terminal is connected to an absorption load module.

[0015] Furthermore, the control module also includes a storage module and an output module. The storage module is used to record capacitor configuration status and impedance data, and the output module includes a local output module and a remote output module, supporting local visualization of Smith charts and remote structured data output.

[0016] The present invention also provides an automatic detection method for radio frequency matching devices, applied to the aforementioned device, comprising the following steps:

[0017] Step S1, Self-calibration: Control RF switch S3 to switch to the Open port, detect the absorption load impedance offset and adjust the capacitor compensation;

[0018] Step S2, Matching Range Test: With the RF power off, adjust C1-C4 to the four extreme combinations of 0% / 100% and collect impedance data;

[0019] Step S3, Matching Time and Stability Test: Adjust the simulated load impedance according to the preset curve in microseconds to simulate the start-up stage of the process chamber, and detect the standing wave ratio and output port data.

[0020] Furthermore, the four sets of capacitors are combined as follows:

[0021] C1_DUT=0% + C2_DUT=0%;

[0022] C1_DUT=0% + C2_DUT=100%;

[0023] C1_DUT=100% + C2_DUT=0%;

[0024] C1_DUT=100% + C2_DUT=100%.

[0025] Furthermore, the simulated load impedance adjusted by the preset curve includes the pre-ionization stage impedance Z1, the breakdown stage impedance Z3, and the steady-state stage impedance Z4; during the test, the voltage and current data of the output ports Port#1 and Port#2 are collected in real time through the second and third probes; in the stability test, the threshold value of the standing wave ratio VSWR is ≤1.2.

[0026] Furthermore, the difference value δ during the self-calibration phase is stored in the control module, and the impedance curve data originates from the measured process chamber parameters.

[0027] Compared with existing technologies, this invention has the following advantages: This invention reproduces the impedance environment in complex process chambers through an adjustable simulated load module, avoiding the usage costs and maintenance issues of real process chambers, improving testing efficiency, and replacing the solution requiring a process chamber for RF matching unit testing, thus achieving fully automated testing of process chambers; the control module adjusts the capacitance value within 1-100μs according to a preset curve, realistically restoring the impedance transition process during the plasma ignition stage, improving the accuracy of matching stability detection, and accurately simulating microsecond-level impedance surges; the control module adjusts C3_DUT to 0%, and respectively connects C1_DUT and C... The 2_DUT is adjusted to 0% and 100%, with four possible combinations in pairs, to fully test the impedance matching range of the RF matching unit in the four quadrants of the Smith chart. The four extreme capacitance combinations fully cover the matching boundary, solving the problem of existing technologies that only test the central area. The impedance difference δ of the absorbing load DL is detected periodically and automatically compensated to ensure that the test accuracy error is small during long-term use. The self-calibration mechanism compensates for the aging offset of the equipment. The multi-port RF matching unit can be compatible with testing by increasing the number of links, and the simulated load capacitor can be replaced with a relay or voltage-controlled diode. The modular design supports flexible expansion and is suitable for high-frequency scenarios. Attached Figure Description

[0028] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the automatic detection device for radio frequency matching devices in Example 1;

[0030] Figure 2 This is a schematic diagram of the test status of a dual-output RF matching circuit.

[0031] Figure 3 This is a schematic diagram of the data from the four points where the matching range test output C3=0%. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] The technologies involved in this application will first be described in conjunction with the accompanying drawings. It should be noted that the following descriptions of various technologies are only for the purpose of making the content of this application easier to understand and do not constitute a limitation on the scope of protection of this application; furthermore, the embodiments and features in the embodiments of this application can be combined with each other unless otherwise specified. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0034] Example 1

[0035] like Figure 1 As shown, this embodiment provides an automatic detection device for radio frequency matching devices, including a matching range detection circuit 10, an analog load module 20, an absorption load module 30, and a control module 40.

[0036] The matching range detection circuit 10 includes an RF power supply 101, a first probe 102, an RF matching unit 103, a second probe 104, a third probe 105, an RF switch S1, and an RF switch S2. The RF power supply 101 is used to generate an RF signal of a specific frequency and power. The first probe 102 is used to collect specific RF parameters. The RF matching unit 103 is used for testing. The second probe 104 and the third probe 105 are used to collect specific RF parameters. The RF switches S1 and S2 are single-pole double-throw RF switches. The RF power supply 101 is connected to the first probe 102 via an RF coaxial cable or an RF connector. The first probe 102 is connected to the input terminal of the RF matching unit 103.

[0037] The simulated load module 20 is connected to the second probe 104 and the third probe 105 via an RF coaxial cable. The simulated load module 20 includes a first impedance tuning module 201A and a second impedance tuning module 201B. The first impedance tuning module 201A includes a vacuum adjustable capacitor C1, a vacuum adjustable capacitor C2, and an inductor L1; the second impedance tuning module 201B includes a vacuum adjustable capacitor C3, a vacuum adjustable capacitor C4, and an inductor L2. C1, C2, and L1 are interconnected via a metal connecting strip, and L1 is grounded; C3, C4, and L2 are interconnected, and L2 is grounded. C2 and C3 are connected to the Load terminal of the RF switch S3 via a metal connecting strip. In high-frequency applications, the inductor can be replaced with a microstrip line, while in low-frequency applications, the inductor is a fixed metal component (such as a spiral or angled type).

[0038] The absorption load module 30 includes a probe 301 and an absorption load DL. The probe 301 is connected to the Com port of the RF switch S3 and is connected to the absorption load DL through an RF coaxial cable. The absorption load DL is grounded.

[0039] The control module 40 includes a microcontroller and a capacitor adjustment element.

[0040] Specifically, the capacitor adjustment element includes stepper motors M1-M4; the control module 40 is based on a microcontroller and controls the switching of RF switches S1, S2, and S3 and the step adjustment of stepper motors M1-M4; the probe collects the impedance amplitude and phase angle parameters under the four combinations in real time and transmits them to the control module 40 through an ADC converter.

[0041] Specifically, the capacitance adjustment method can also be relay or voltage-controlled diode adjustment, with a capacitance range of 0-200pF; in addition to stepper motors M1-M4, the capacitance adjustment element can also be a relay or voltage-controlled diode.

[0042] The technical effect of the above solution is that it solves the problem of existing technology relying on process chambers by replacing fixed load with adjustable simulated load.

[0043] Example 2

[0044] This embodiment provides an automatic detection device for radio frequency matching devices. Based on Embodiment 1, the output port of the radio frequency matching device 103 is multi-port, specifically the ports of the radio frequency matching device 103 are Port#1 and Port#2. The control module 40 also includes a storage module and an output module. The storage module includes an embedded Flash memory or an external database MySQL. The storage module is used to store the original impedance data, timestamps, and capacitor configuration status corresponding to each combination. The output module includes a local output module and a remote output module. The local output module is used to output a Smith chart trajectory of the impedance data under the four capacitor combinations for visualization. The remote output module is used to output structured data to a remote system.

[0045] The technical effects of the above solution are as follows: it can intuitively display the impedance matching boundary range of the RF matching device at Port#1, which is convenient for automatic processing and analysis. It can also use Port#2 to test the impedance matching range boundary range. It can also be expanded to multiple ports, such as a 4-port matching device, and corresponding link components can be added accordingly.

[0046] Example 3

[0047] This embodiment provides an automatic testing device for radio frequency matching devices. Based on Embodiment 1, the capacitor adjustment method of the simulated load module 20 adopts a relay activation method, with the relay activation time on the order of microseconds. C1-C4 are interconnected via a metal connecting strip. Specifically, during self-calibration and testing, the relays activate according to a preset sequence, which is a stepped change curve. The adjustment time parameter can also be obtained by looking up a table to obtain the activation sequence of the relays at different times, and the number of discrete tables.

[0048] The technical effect of the above solution is that by adjusting the impedance change during the simulated ignition stage at the microsecond level, the mechanical delay problem in high-frequency scenarios is solved.

[0049] Example 4

[0050] This embodiment provides an automatic detection method for radio frequency matching devices, which is applied to an automatic detection equipment for radio frequency matching devices. The specific steps of the automatic detection method include:

[0051] Step S1, Self-calibration: Control the RF switch to detect the impedance of the absorption load DL. If it deviates from the preset value, calculate the difference δ and adjust the capacitor compensation.

[0052] Step S2, Test matching range: Turn the RF power supply to OFF, select the control switch, adjust the simulated load capacitance combination, and collect impedance data through the probe;

[0053] Step S3, Test matching time and stability: Control the simulated load impedance to change according to the preset curve, and check whether the standing wave ratio is lower than the threshold during the microsecond simulated start-up stage.

[0054] The technical effect of the above solution is that it solves the problem that existing methods cannot automatically simulate the ignition stage.

[0055] Example 5

[0056] This embodiment provides an automatic detection method for radio frequency matching devices, using the automatic detection device for radio frequency matching devices from Embodiment 2. The specific steps include:

[0057] Step S1, Self-calibration: Turn the RF power supply 101 to OFF state. The microcontroller controls the RF switch S3 to connect the probe 301 to the Open port. The probe 301 detects whether the impedance of the absorption load DL is at the preset impedance value. If there is a difference from the preset impedance value, calculate the difference value δ, and control the stepper motors M1, M2, M3 and M4 to adjust the vacuum adjustable capacitors C1-C4 to compensate for the difference from the preset impedance value. After the compensation is completed, store the change parameters of M1 to M4.

[0058] Step S2, Testing the Matching Range: With RF power supply 101 in the OFF state, RF switch S1 switched to Open, and RF switch S2 switched to Load. C3_DUT is adjusted to 0%, and C1_DUT and C2_DUT are adjusted to 0% and 100% respectively, resulting in four combinations. In a preferred embodiment, the control module adjusts C3_DUT to 0%, and C1_DUT and C2_DUT are adjusted to 0% and 100% respectively, resulting in four combinations. The second probe 104 collects impedance values, which are stored and output by the control module. Alternatively, RF switch S1 can be switched to Load, and RF switch S2 can be switched to Open. The difference between the two methods is that they test different output ports, but the effect is the same.

[0059] Further explanation is needed: The control module adjusts C3_DUT to 0%, and then adjusts C1_DUT and C2_DUT to 0% and 100% respectively, resulting in four combinations. The second probe 104 collects the impedance values ​​of these four combinations, which are then stored and output by the control module. The control module also adjusts C3_DUT to 100%, and then adjusts C1_DUT and C2_DUT to 0% and 100% respectively, resulting in four combinations. The matching range test outputs matching range data for C3=0% and data for C3=100%. For example... Figure 3 As shown, the data for the four points where C3=0% is similar to the data for C3=100%.

[0060] Step S3, Testing Matching Time and Stability: RF switch S3 is switched to Load, RF switches S1 and S2 are switched to Load, and M1-M4 is controlled to adjust the capacitance of vacuum adjustable capacitors C1-C4. The second probe 104 and the third probe 105 detect and calculate whether the impedance value of the analog load module 20 is the preset impedance value Z1 in the pre-ionization stage. If it is not Z1, M1-M4 is used to continue adjusting until the preset impedance value Z1 is reached. After adjustment, the compensation difference value δ is the compensated impedance value Z2. RF matching device 103 is adjusted to automatic matching mode. The microcontroller controls the RF power supply 101 to output the preset power at the preset operating frequency. The microcontroller controls M1-M4 to adjust the overall impedance of the analog load module 20 according to the preset curve to the breakdown stage impedance value Z3. After adjusting to Z3, it is adjusted according to the preset curve to the steady-state stage impedance value Z4. The first probe 102 detects whether the VSWR is lower than the preset VSWR Vswr within a preset time to determine whether the RF matching device 103 has completed matching. The preset impedance values ​​Z2 are adjusted to be in the microsecond range for Z3 and Z4 to simulate the drastic impedance changes during the ignition phase of the plasma process chamber. The preset impedance values ​​can be adjusted according to different process chambers, and the adjustment values ​​are derived from measured values. At the same time, the second probe 104 and the third probe 105 record and store the VI data of the output ports Port#1 and Port#2 of the RF matching unit 103 during the impedance change of the simulated load module 20 from Z2 to Z4.

[0061] Specifically, the step of adjusting C1_DUT and C2_DUT to 0% and 100% respectively, and combining them in pairs, results in four combinations: Combination 1: C1_DUT=0% + C2_DUT=0%, Combination 2: C1_DUT=0% + C2_DUT=100%, Combination 3: C1_DUT=100% + C2_DUT=0%, Combination 4: C1_DUT=100% + C2_DUT=100%.

[0062] like Figure 2As shown, the working state of the RF matching unit 103 during the test is as follows: Port#1 is connected to RF switch S1, and Port#2 is connected to RF switch S2; the vacuum adjustable capacitors C1-C4 and inductors L1 and L2 in the analog load module 20 constitute two sets of independent adjustable circuits.

[0063] The technical effects of the above solution are as follows: by combining four sets of extreme capacitance values, the impedance matching boundary range of the RF matching unit 103 at the output ports Port#1 and Port#2 is fully detected, providing data support for the performance evaluation of the matching unit; self-calibration solves the impedance shift caused by the absorption load during long-term use.

[0064] In summary, this invention provides a testing scheme that can automatically simulate the dynamic impedance characteristics of process chambers, support multi-port testing, and has self-calibration capabilities, thereby solving the problems of incomplete performance evaluation and low testing efficiency of RF matching devices.

[0065] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. The above descriptions are only preferred embodiments of this application. It should be noted that due to the limitations of written expression, while there are objectively infinite specific structures, those skilled in the art can make several improvements, modifications, or changes without departing from the principles of this application, and can also combine the above technical features in an appropriate manner. These improvements, modifications, changes, or combinations, or the direct application of the inventive concept and technical solution to other situations without modification, should all be considered within the scope of protection of this application.

Claims

1. An automatic testing device for radio frequency matching devices, characterized in that, The automatic testing equipment includes a matching range detection circuit (10), an analog load module (20), an absorbent load module (30), and a control module (40): The matching range detection circuit (10) includes an RF power supply (101), a first probe (102), an RF matching unit (103), a second probe (104), a third probe (105), a first RF switch (S1), and a second RF switch (S2). The RF power supply (101) is connected to the first probe (102) via an RF coaxial cable. The first probe (102) is connected to the input terminal of the RF matching unit (103). The first output terminal of the RF matching unit (103) is connected to the common terminal of the second RF switch (S2). The second output terminal of the RF matching unit (103) is connected to the common terminal of the first RF switch (S1). One end of the second probe (104) is connected to the load terminal of the second RF switch (S2), and one end of the third probe (105) is connected to the load terminal of the first RF switch (S1). The matching range detection circuit (10) is used to establish an RF signal path and collect impedance parameters. The analog load module (20) includes a first impedance tuning module (201A) and a second impedance tuning module (201B). Both the first impedance tuning module (201A) and the second impedance tuning module (201B) include a vacuum adjustable capacitor and an inductor. The first impedance tuning module (201A) includes a first vacuum adjustable capacitor (C1), a second vacuum adjustable capacitor (C2), and a first ground inductor (L1). One end of the first vacuum adjustable capacitor (C1) is connected to the other end of the third probe (105), and the other end of the first vacuum adjustable capacitor (C1) is connected to one end of the first ground inductor (L1). The other end of the first ground inductor (L1) is grounded. One end of the second vacuum adjustable capacitor (C2) is connected to the other end of the third probe (105), and the second vacuum... The other end of the adjustable capacitor (C2) is connected to the load terminal of the third RF switch (S3); the second impedance tuning module (201B) includes a third vacuum adjustable capacitor (C3), a fourth vacuum adjustable capacitor (C4) and a second ground inductor (L2). One end of the fourth vacuum adjustable capacitor (C4) is connected to the other end of the second probe (104), and the other end of the fourth vacuum adjustable capacitor (C4) is connected to one end of the second ground inductor (L2). The other end of the second ground inductor (L2) is grounded. One end of the third vacuum adjustable capacitor (C3) is connected to the other end of the second probe (104), and the other end of the third vacuum adjustable capacitor (C3) is connected to the load terminal of the third RF switch (S3); the analog load module (20) is used to dynamically simulate the impedance characteristics of the process chamber; The absorption load module (30) includes a probe (301) and an absorption load (DL); one end of the probe (301) is connected to one end of the absorption load (DL), and the other end of the absorption load (DL) is grounded; the other end of the probe (301) is connected to the common terminal of the third RF switch (S3); the absorption load module (30) is used to provide a reference impedance and achieve self-calibration. The control module (40) is used to control the on / off state of the first radio frequency switch (S1), the second radio frequency switch (S2), and the third radio frequency switch (S3), as well as to adjust the capacitance value and monitor the output data of the probe. The control module (40) adjusts the capacitance value within 1-100μs according to a preset curve to restore the impedance transition process of the plasma ignition stage.

2. The automatic detection device for radio frequency matching devices according to claim 1, characterized in that, The vacuum adjustable capacitor in the analog load module (20) has a capacitance range of 0-200pF and can be adjusted by a stepper motor, relay or voltage-controlled diode.

3. The automatic radio frequency matching device according to claim 1, characterized in that, The control module (40) includes a microcontroller and a capacitor adjustment element.

4. The automatic detection device for radio frequency matching devices according to claim 1, characterized in that, The capacitors of the analog load module (20) are interconnected by metal connecting strips, and the inductors are grounded.

5. The automatic detection device for radio frequency matching devices according to claim 1, characterized in that, The control module (40) also includes a storage module, an output module, and a communication control module for controlling the vacuum capacitor value module. The storage module is used to record the capacitor configuration status, impedance data, and probe output data. The output module includes a local output module and a remote output module, supporting local visualization of Smith charts and remote structured data output.

6. An automatic detection method for radio frequency matching devices, applied to the device according to any one of claims 1-5, characterized in that, Includes the following steps: Step S1, Self-calibration: Control the third RF switch (S3) to switch to the Open port, detect the absorption load impedance offset and adjust the capacitor compensation; Step S2, Matching Range Test: With the RF power supply (101) off, the control module (40) adjusts the capacitance value C3_DUT of the third vacuum adjustable capacitor (C3) to 0%, and adjusts the capacitance value C1_DUT of the first vacuum adjustable capacitor (C1) and the capacitance value C2_DUT of the second vacuum adjustable capacitor (C2) to form four combinations, and collects impedance data; the four combinations specifically include: C1_DUT and C2_DUT are both 0%, C1_DUT is 0% and C2_DUT is 100%, C1_DUT is 100% and C2_DUT is 0%, and C1_DUT and C2_DUT are both 100%; Step S3, Matching Time and Stability Test: The third RF switch (S3) is switched to Load, and the first RF switch (S1) and the second RF switch (S2) are switched to Load. The capacitance values ​​of the first vacuum adjustable capacitor (C1), the second vacuum adjustable capacitor (C2), the third vacuum adjustable capacitor (C3), and the fourth vacuum adjustable capacitor (C4) are adjusted. The impedance value of the analog load module (20) is detected and calculated by the second probe (104) and the third probe (105) to determine whether it is the preset impedance value Z1 of the pre-ionization stage. If it is not Z1, the adjustment continues until it is adjusted to Z1. After the adjustment is completed, the compensation difference value δ is the compensated impedance value Z2. The RF matching unit (103) is adjusted to automatic matching. In the matching mode, the control module (40) controls the RF power supply (101) to output the preset power at the preset operating frequency. The control module (40) controls the overall impedance of the analog load module (20) to be adjusted to the breakdown stage impedance value Z3 according to the preset curve. After being adjusted to Z3, it is adjusted to the steady-state stage impedance value Z4 according to the preset curve. The first probe (102) detects whether the standing wave ratio is lower than the preset standing wave ratio Vswr within a preset time to determine whether the RF matching device (103) has completed the matching. At the same time, the second probe (104) and the third probe (105) record and store the VI data of the first and second output terminals of the RF matching device (103) during the time when the impedance of the analog load module (20) changes from Z2 to Z4.

7. The automatic detection method for radio frequency matching devices according to claim 6, characterized in that, The preset VSWR Vswr is ≤ 1.2.

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