High-power high-stability remote plasma source fuzzy hysteresis control method and circuit

Abstract

The invention belongs to the technical field of plasma sources, and provides a high-power high-stability remote plasma source fuzzy hysteresis control method and a circuit, when a reaction cavity is successfully ignited, a plasma source system is controlled to work at constant-frequency variable-duty-ratio constant-power output, and the method comprises the following steps: according to a sampled current value, a duty ratio, a predicted current value and a predicted duty ratio, calculating a constant-frequency variable-duty-ratio constant-power output value; respectively obtaining error control variables e and ec; the error control variables e and ec serve as input values of a fuzzy controller, and the actual control quantity hr output by the fuzzy controller is obtained; obtaining compensation variables # imgabs0 # and # imgabs1 # of the current and the duty ratio based on the error control variables e and ec; and taking the actual control quantity hr as the ring width value of a hysteresis comparator, and respectively compensating the current # imgabs4 # and the duty ratio # imgabs5 # at the moment k by outputting compensation variables # imgabs2 # and # imgabs3 # according to a preset rule. According to the method provided by the invention, a power window in a relatively wide range can be ensured, so that the working stability of the remote plasma source is improved, and the uniformity of a semiconductor manufacturing process is improved.

Description

Technical Field

[0001] The invention relates to the technical field of plasma sources, and in particular to a fuzzy hysteresis control method and circuit for a high-power and high-stability remote plasma source. Background Art

[0002] As a new technology that uses high-energy plasma to process materials, plasma technology has been widely used in industrial semiconductors, biomedicine, food environment and other fields. Remote plasma sources are more widely used in surface cleaning, modification, deposition and other processes of various materials due to their high efficiency, high flexibility and sustainability, and their application prospects are becoming increasingly broad. However, the current remote plasma source systems generally have problems such as low power output, few types of ionized gases that can be satisfied, small gas flow range and unstable plasma concentration, which lead to poor process uniformity and etching rate. In addition, when processing large samples or large batches, the multi-source parallel and multi-stage series methods can improve the power and processing efficiency, but it brings the problem of difficulty in synchronous control of remote plasma sources.

[0003] At present, remote plasma source systems generally have problems such as low power output, few types of ionized gases that can be satisfied, small gas flow range and unstable plasma concentration. When processing large samples or large batches, the method of multi-source parallel and multi-stage series connection can improve the power supply power and processing efficiency, but it brings about problems such as resource waste, poor uniformity and difficulty in synchronous control; therefore, how to ensure the working stability of each system and the accuracy of the control quantity when the plasma source is in the process of power increase has become a problem that needs to be urgently solved by technical personnel in this field. Summary of the invention

[0004] In view of the defects in the prior art, the present invention provides a high-power and high-stability remote plasma source fuzzy hysteresis control method and circuit to solve the problem of low output power of the current remote plasma source system. In a first aspect, the present invention provides a high-power and high-stability remote plasma source fuzzy hysteresis control method, when the reaction chamber is ignited successfully, the plasma source system is controlled to operate at a constant power output with a fixed frequency and a variable duty cycle, comprising: According to the sampled current value and duty cycle, the predicted current value and duty cycle, the error control variables e and ec are obtained respectively; wherein, , , and are the current sampling value and duty cycle at time k, and are respectively the current sampling value and duty cycle predicted at time k+1; The error control variables e and ec are used as the input values ​​of the fuzzy controller to obtain the actual control quantity hr output by the fuzzy controller; Obtain compensation variables for current and duty cycle based on error control variables e and ec and ; The actual control variable hr is used as the loop width value of the hysteresis comparator, and the compensation variable is output according to the preset rules. and The current at time k is and duty cycle Make compensation.

[0005] It can be seen from the above technical solution that the method provided by the present invention combines fuzzy control and variable loop width hysteresis comparator control to feedback compensation to the output current The duty cycle D can improve the power regulation accuracy of the system, ensure a wider power window, improve the working stability of the remote plasma source, and enhance the uniformity of the semiconductor process.

[0006] Optionally, to output compensation variables The current at the current moment When making compensation, the preset rules include: When the power error When the current Subtracting variables Feedback compensation to the output current at the next moment ; When the power error When maintaining the k+1 moment and k moment Consistency; When the power error When the current Add variables Feedback compensation to the output current at the next moment .

[0007] Optionally, to output compensation variables The duty cycle at the current moment When making compensation, the preset rules include: When the current error When the current duty cycle Subtracting variables Feedback compensation to the output duty cycle at the next moment ; When the current error When , the switch state of the previous moment is maintained to keep the duty cycle D relatively stable; When the current error When the current duty cycle Add variables Feedback compensation to the output duty cycle at the next moment .

[0008] Optionally, at time k+1 The predictions are based on the following method: Resonant frequency of a resonant converter and switching frequency The normalized value of They are: ; ; is the output frequency; Equivalent resistance The RMS value of the fundamental component of the input square wave voltage is expressed as: ; ; Among them, the inductance ratio of the equivalent circuit is , characteristic impedance and quality factors They are ; ; ; , and They are the resonant inductance, resonant capacitance and leakage inductance of the resonant converter respectively; The primary winding current and voltage They are: , , Predict the primary winding current at time k+1 .

[0009] Optionally, the duty cycle d (k+1) at time k+1 is obtained by fitting an inverse tangent function: , in, is a sampling cycle time, A is the time-varying factor, and B is the factor affecting the duty cycle change rate.

[0010] Optionally, the error control variables e and ec are used as input values ​​of the fuzzy controller to obtain the actual control quantity hr output by the fuzzy controller, including: According to the error control variables e, ec and the membership function, the membership values ​​E and EC are determined; the membership values ​​E and EC are divided into 5 fuzzy subspaces, and the language values ​​are: too less than the lower limit of the set range NB, slightly less than the lower limit of the set range NS, within the set range ZO, slightly greater than the upper limit of the set range PS, and too greater than the upper limit of the set range PB; According to the membership values ​​E and EC, the fuzzy output H is determined; the fuzzy output H is divided into five fuzzy subspaces, and the language values ​​are: negative large NB, negative small NS, zero ZO, positive small PS, and positive large PB; According to the fuzzy output H, the actual control quantity hr is obtained by defuzzification.

[0011] Optionally, after receiving the ignition signal, controlling the plasma source system to operate at a constant current output at a resonant frequency point to ignite the reaction chamber includes: Controlling the introduction of exciting gas; At the first preset time before the ignition operation, the resonant output current reference value Instantly reduce to the current reference value ; When receiving the ignition signal, the relay S is driven to close, otherwise the system continues to pass the excitation gas; The resonant output current reference value The current value sampled by the power circuit Output current error after comparison , after current PI modulation, the PWM drive unit is started; Determine whether it is satisfied And it is maintained for more than the second preset time. If it is satisfied, then it is determined whether the system is ignited successfully. Otherwise, it is ignition failure, the system reports an error and disconnects the relay S; If it is determined that the ignition is abnormal, the plasma ignition duration and ignition voltage are adaptively adjusted, and the ignition duration and ignition voltage are amplified by a ratio of (1+K) and cyclically processed; If the ignition fails after exceeding the cycle upper limit, it is judged as an ignition failure, the system reports an error and disconnects the relay; when the ignition is successful, the relay is disconnected, the constant current stage ends and the constant power stage begins.

[0012] It can be seen from the above technical solutions that the mixed control method of constant current and constant power can be used to ionize a variety of gases and a wider range of gas flow rates, shorten the process time, and improve the applicability and etching rate of the remote plasma source.

[0013] In a second aspect, the present invention provides a high-power and high-stability remote plasma source fuzzy hysteresis control circuit, using the remote plasma source fuzzy hysteresis control method provided by any possible implementation of the first aspect, including a control unit, a PWM drive unit, a resonant converter, an ignition circuit, a sampling unit, a relay and a reaction chamber; The control unit is used to control the PWM drive unit to output a pulse signal and control the relay to be closed or disconnected; The resonant converter converts the pulse signal output by the PWM drive unit into an AC source, and is used to provide an input AC source for the ignition circuit; The ignition circuit generates a high-voltage ignition signal to cause the plasma load in the reaction chamber to oscillate and ionize at a high frequency; The sampling unit is used to collect the ignition current of the ignition circuit, and the output voltage and output current of the resonant converter; The resonant converter includes a transformer T1, and the ignition circuit is connected to a secondary coil N3 of the transformer T1; The relay is controlled by the control unit to be closed or disconnected.

[0014] Optionally, a maintaining circuit is further included, wherein the maintaining circuit is connected in series with the secondary coil N2 of the transformer T1, and the reaction cavity is used as the secondary side of the transformer T1 to provide only the cavity with , to meet the low-voltage energy input in the constant power stage; The maintaining circuit is used to maintain the bus voltage stable after entering the constant power stage from the constant current stage when the relay is disconnected.

[0015] By adopting the above technical solution, the present application has the following beneficial effects: The method provided by the present invention combines fuzzy control and variable loop width hysteresis comparator control, and feedback compensation is given to the output current and duty cycle D, which can improve the power regulation accuracy of the system, ensure a wider range of power windows, improve the working stability of the remote plasma source, and enhance the uniformity of the semiconductor process technology.

[0016] The present invention adopts a constant current and constant power mixed control method, which can ionize multiple gases and a wider range of gas flow rates, shorten the process time, and improve the applicability and etching rate of the remote plasma source. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0018] Figure 1 A schematic diagram of a high-power and high-stability remote plasma source fuzzy hysteresis control circuit provided by an embodiment of the present invention is shown; Figure 2 A flow chart of the constant current stage in the fuzzy hysteresis control method of a remote plasma source provided by an embodiment of the present invention is shown; Figure 3 One of the flow charts of the constant power stage in the fuzzy hysteresis control method of the remote plasma source provided by the embodiment of the present invention is shown; Figure 4 The second flowchart of the constant power stage in the fuzzy hysteresis control method of the remote plasma source provided by the embodiment of the present invention is shown; Figure 5 A schematic diagram of a fuzzy controller provided by an embodiment of the present invention is shown; Figure 6 A schematic diagram of a membership function provided by an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0019] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention. It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0020] like Figure 1 As shown, this embodiment provides a high-power remote plasma source fuzzy hysteresis control circuit, including a remote plasma source power circuit, a constant current stage unit, and a constant power stage unit; The remote plasma source power circuit includes a control unit, a PWM drive unit, a DC / AC resonant converter, an ignition circuit and a sampling unit, and a reaction chamber; The control unit is used to control the PWM drive unit to output a pulse signal; The PWM drive unit controls the output current of the resonant converter; The output current of the resonant converter affects the input current of the ignition circuit; the resonant converter converts the pulse signal output by the PWM drive unit into an AC source, and is used to provide an input AC source for the ignition circuit; The ignition circuit generates a high-voltage ignition signal to ionize the plasma load with high-frequency oscillation, and the resonant converter is used to provide an input AC source; The resonant converter includes a transformer T1, and the ignition circuit is connected to the secondary coil N3 of the transformer T1; The sampling unit is used to collect the ignition current of the ignition circuit, and the output voltage and output current of the resonant converter; Relay S is controlled by the control unit to be closed or disconnected; The constant current stage unit, after receiving the ignition signal, outputs a current and duty cycle that enables the plasma source system to operate at a constant current output of ±1% near the resonant frequency point, so as to ignite the reaction chamber; The constant power stage unit, when the reaction chamber is ignited successfully, outputs the current and duty cycle that make the plasma source system work at a constant power output with a fixed frequency and a variable duty cycle.

[0021] Optionally, the remote plasma source power circuit further includes a maintaining circuit, which is connected in series with the secondary coil N2 of the transformer T, and the vacuum reaction chamber is used as the secondary side of the high-frequency transformer to only provide the chamber with To meet the low-voltage energy input in the ionization maintenance stage; the maintenance circuit is used to maintain the bus voltage stability after entering the constant power stage (ionization stage) from the constant current stage (ignition stage) when the relay is disconnected; like Figure 2 As shown, the present embodiment provides a remote plasma source fuzzy hysteresis control method, after receiving the ignition signal, controls the plasma source system to operate at a constant current output of ±1% near the resonant frequency point to ignite the reaction chamber. At this time, the system is in a constant current stage, i.e., an ignition working stage, including: S110. After the remote plasma source is turned on, the system first sets the gas current excitation threshold , control the introduction of exciting gas; S120. Through the stage adjustment unit, 50ms before the ignition operation, the resonant output current reference value Instantly reduce to the current reference value This step can effectively avoid surge current and protect relay S.

[0022] S130. Determine whether an ignition signal is received. When an ignition signal is received, the relay S is driven to close. Otherwise, the system then passes the excitation gas; S140. Set the resonant output current reference value The current value sampled by the power circuit Output current error after comparison , after current PI modulation, the PWM drive unit is started; S150. Determine whether the And maintain for more than 500ms. If it is satisfied, then judge whether the system is ignited successfully. Otherwise, if the ignition fails, the system will report an error and disconnect the relay S. S160. If the ignition is determined to be abnormal, the plasma ignition duration and ignition voltage are adaptively adjusted, and the ignition duration and ignition voltage are amplified by a ratio of (1+K) and cyclically processed; the upper limit of the number of cycles is 10 times to improve the ignition success rate; S170. If the ignition fails after exceeding the cycle upper limit, it is determined that the ignition failed, the system reports an error and disconnects the relay; when the ignition is successful, the relay is disconnected, the constant current stage ends and the constant power stage begins.

[0023] like Figure 3-4 As shown, the present embodiment provides a remote plasma source fuzzy hysteresis control method, when the reaction chamber is ignited successfully, the plasma source system is controlled to operate at a constant power output with a fixed frequency and a variable duty cycle, including: S210. Obtain error control variables e and ec according to the sampled current value and duty cycle, and the predicted current value and duty cycle, respectively.

[0024] in, , , and are the current sampling value and duty cycle at time k, and They are respectively the current sampling value and duty cycle predicted at time k+1.

[0025] Specifically, at time k+1 The predictions are based on the following method: The resonant converter in this embodiment is an LCL resonant converter. Due to the resonance of the converter, the resonant frequency of the converter is defined as and switching frequency The normalized value of They are: ; ; is the output frequency; Equivalent resistance The RMS value of the fundamental component of the input square wave voltage is expressed as: ; ; Among them, the inductance ratio of the equivalent circuit is , characteristic impedance and quality factors They are ; ; ; , and They are the resonant inductance, resonant capacitance and leakage inductance of the resonant converter respectively; It can be seen that the primary winding current and voltage They are: , , Predict the primary winding current at time k+1 .

[0026] From the characteristics of the LCL resonant circuit, we can see that when the frequency is fixed, the resonant current Remain relatively constant; Then the actual power at time k is The plasma voltage / current can be sampled and To express:

[0027] in, For current With voltage The vector angle of ; The duty cycle at the current time k It can be obtained by passing the current error e1 in the current loop into the current PI modulation, according to the duty cycle of the measured object at the current time k Fit and predict the duty cycle at time k+1 ; Duty cycle at time k+1 Fitting by the inverse tangent function yields: , in, is a sampling cycle time, A is the time-varying factor, and B is the factor affecting the duty cycle change rate.

[0028] S220. Use the error control variables e and ec as input values ​​of the fuzzy controller to obtain the actual control quantity hr output by the fuzzy controller.

[0029] The fuzzy controller quantifies the input and feedback to obtain the system errors e and ec as the input of the fuzzy controller; fuzzifies the control variables, determines the fuzzy domain and the corresponding membership function, and obtains E and EC; then makes decisions based on the fuzzy control rules established in advance to obtain the fuzzy output H; defuzzifies the fuzzy output H to obtain the actual control quantity hr, which is sent to the control mechanism to complete the entire control process; Assume that the input fuzzy sets e and ec of the fuzzy controller and the fuzzy set of its output H are as follows: In this embodiment, the difference between the resonant output current reference value iref and the sampled current value ipri is used to control the bandwidth hr of the hysteresis controller, and the input fuzzy sets e and ec are divided into 5 fuzzy subspaces, and the language values ​​are: too less than the lower limit of the set range (NB), slightly less than the lower limit of the set range (NS), within the set range (ZO), slightly greater than the upper limit of the set range (PS), and too greater than the upper limit of the set range (PB). The hysteresis width hr is divided into 5 fuzzy subspaces, and the language values ​​are: negative large (NB), negative small (NS), zero (ZO), positive small (PS), and positive large (PB). Then: , , The basic domain of the input fuzzy sets e and ec is [-1, 1], and the basic domain of the hysteresis width hr is [-1, 1]. To ensure that the fuzzy controller has high sensitivity, at the boundary of the basic domain, the input membership function of each variable selects a triangular function with high sensitivity and is evenly distributed.

[0030] Step S220 specifically includes: S221. According to the error control variables e, ec and the membership function, the membership values ​​E and EC are determined; the membership values ​​E and EC are divided into 5 fuzzy subspaces, and the language values ​​are: too less than the lower limit of the set range NB, slightly less than the lower limit of the set range NS, within the set range ZO, slightly greater than the upper limit of the set range PS, and too greater than the upper limit of the set range PB; S222. According to the membership values ​​E and EC, the fuzzy output H is determined; the fuzzy output H is divided into five fuzzy subspaces, and the language values ​​are: negative large NB, negative small NS, zero ZO, positive small PS, and positive large PB; S223. According to the fuzzy output H, defuzzify to obtain the actual control quantity hr.

[0031] like Figure 6 As shown, (a)-(c) are the membership function diagrams of the output quantities E, EC, and H in the fuzzy rule base of the fuzzy controller. Table 1 also shows the fuzzy rule base of the fuzzy sets E, EC and the fuzzy output quantity H.

[0032] Table 1

[0033] The fuzzy reasoning method used in this embodiment is the Mamdani reasoning method. Mamdani is a method commonly used in fuzzy control. Its essence is a synthetic reasoning method. The i-th rule in the rule base is expressed as: Ri "If e is E and ec is EC, Then hr is H" Among them, e, ec, and hr are the language variables corresponding to E, EC, and H respectively; Among them, hr is the fuzzy output, and the internal fuzzy relationship is:

[0034] The specific steps of fuzzy reasoning are: perform fuzzy reasoning on fuzzy input quantities E and EC according to the set rule R, and output fuzzy output quantity H; ; Then the fuzzy relationship within the entire rule base is:

[0035] The specific steps of defuzzification are: using the centroid method, find the centroid value of each element in the fuzzy output H and its corresponding membership degree to obtain the output hr.

[0036]

[0037] Among them, hr is the output of the fuzzy controller, is the central value of the membership function interval corresponding to the output quantity, for The corresponding membership degree; The steps for obtaining the output quantity hr include: firstly, fuzzifying the input signal, then performing fuzzy reasoning according to the set data set and rule set to obtain the fuzzy output quantity H; finally, using the centroid method to defuzzify the fuzzy output quantity H, and finally obtaining the output quantity hr.

[0038] S230. Obtain compensation variables of current and duty cycle based on error control variables e and ec and .

[0039] In this step, the compensation variable and It is positively correlated with the error control variables e and ec, and is determined according to the following formula:

[0040]

[0041] m and n are correlation coefficients, which can be selected by those skilled in the art according to actual application conditions.

[0042] S240. The actual control amount hr is used as the loop width value of the hysteresis comparator, and the compensation variable is output according to the preset rules. and The current at time k is and duty cycle Make compensation.

[0043] After fuzzy reasoning, hr is obtained as the loop width value of the hysteresis comparator. At this time, the rules of the variable loop width hysteresis comparator are:

[0044]

[0045] Specifically including output compensation variables The current at the current moment Compensation is performed and the compensation variable is output The duty cycle at the current moment Make compensation.

[0046] Output compensation variable The current at the current moment When making compensation, the preset rules specifically include: When the power error When the current Subtracting variables Feedback compensation to the output current at the next moment ; When the power error When maintaining the k+1 moment and k moment Consistency; When the power error When the current Add variables Feedback compensation to the output current at the next moment .

[0047] Specifically, the actual output power is calculated based on the sampled output voltage and current. , the k+1 moment and k moment After comparison, the current error e is obtained, and the compensation variable of the power loop output is calculated from the current error e ; When the power error of the power loop output When the current Subtracting variables Feedback compensation to the output current at the next moment ; When the power error When maintaining the k+1 moment and k moment Consistent; when the power error When the current Add variables Feedback compensation to the output current at the next moment .

[0048] Output compensation variable The duty cycle at the current moment When making compensation, the preset rules specifically include: When the current error When the current duty cycle Subtracting variables Feedback compensation to the output duty cycle at the next moment ; When the current error When , the switch state of the previous moment is maintained to keep the duty cycle D relatively stable; When the current error When the current duty cycle Add variables Feedback compensation to the output duty cycle at the next moment .

[0049] Specifically, the current loop is offset compensated, and the duty cycle at time k+1 is and k moment After comparison, the duty cycle error ec is obtained, and the compensation variable of the current loop output is calculated based on the duty cycle error ec ;when When the current duty cycle Subtracting variables Feedback compensation to the output duty cycle at the next moment , that is, T1 and T3 are turned off, T2 and T4 are turned on to reduce the duty cycle D; when the current error When the current error is When the current duty cycle Add variables Feedback compensation to the output duty cycle at the next moment , that is, turning on T1 and T3 and turning off T2 and T4 to increase the duty cycle D.

[0050] The above embodiments are only used to introduce the technical solutions of the present application in detail, but the description of the above embodiments is only used to help understand the methods of the embodiments of the present invention and should not be understood as limiting the embodiments of the present invention. Any changes or substitutions that can be easily thought of by those skilled in the art should be included in the protection scope of the embodiments of the present invention.

Claims

1. A high-power and high-stability remote plasma source fuzzy hysteresis control method, characterized in that: When the reaction chamber is ignited successfully, the plasma source system is controlled to operate at a constant power output with a fixed frequency and variable duty cycle, including: According to the sampled current value and duty cycle, the predicted current value and duty cycle, the error control variables e and ec are obtained respectively; wherein, , , and are the current sampling value and duty cycle at time k, and are respectively the current sampling value and duty cycle predicted at time k+1; The error control variables e and ec are used as the input values ​​of the fuzzy controller to obtain the actual control quantity hr output by the fuzzy controller; Obtain compensation variables for current and duty cycle based on error control variables e and ec and ; The actual control variable hr is used as the loop width value of the hysteresis comparator, and the compensation variable is output according to the preset rules. and The current at time k is and duty cycle Make compensation.

2. The method according to claim 1, characterized in that Output compensation variable The current at the current moment When making compensation, the preset rules include: When the power error When the current Subtracting variables Feedback compensation to the output current at the next moment ; When the power error When maintaining the k+1 moment and k moment Consistency; When the power error When the current Add variables Feedback compensation to the output current at the next moment .

3. The method according to claim 2, characterized in that Output compensation variable The duty cycle at the current moment When making compensation, the preset rules include: When the current error When the current duty cycle Subtracting variables Feedback compensation to the output duty cycle at the next moment ; When the current error When , the switch state of the previous moment is maintained to keep the duty cycle D relatively stable; When the current error When the current duty cycle Add variables Feedback compensation to the output duty cycle at the next moment .

4. The method according to claim 1 or 3, characterized in that: At k+1 time The predictions are based on the following method: Resonant frequency of a resonant converter and switching frequency The normalized value of They are: ; ; is the output frequency; Equivalent resistance The RMS value of the fundamental component of the input square wave voltage is expressed as: ； ； Among them, the inductance ratio of the equivalent circuit is , characteristic impedance and quality factors They are ; ; ; , and They are the resonant inductance, resonant capacitance and leakage inductance of the resonant converter respectively; The primary winding current and voltage They are: ， ， Predict the primary winding current at time k+1 .

5. The method according to claim 4, characterized in that The duty cycle d (k+1) at time k+1 is obtained by fitting the inverse tangent function: ， in, is a sampling cycle time, A is the time-varying factor, and B is the factor affecting the duty cycle change rate.

6. The method according to claim 1, characterized in that The error control variables e and ec are used as input values ​​of the fuzzy controller to obtain the actual control quantity hr output by the fuzzy controller, including: According to the error control variables e, ec and the membership function, the membership values ​​E and EC are determined; the membership values ​​E and EC are divided into 5 fuzzy subspaces, and the language values ​​are: too less than the lower limit of the set range NB, slightly less than the lower limit of the set range NS, within the set range ZO, slightly greater than the upper limit of the set range PS, and too greater than the upper limit of the set range PB; According to the membership values ​​E and EC, the fuzzy output H is determined; the fuzzy output H is divided into five fuzzy subspaces, and the language values ​​are: negative large NB, negative small NS, zero ZO, positive small PS, and positive large PB; According to the fuzzy output H, the actual control quantity hr is obtained by defuzzification.

7. The method according to claim 1, characterized in that After receiving the ignition signal, the plasma source system is controlled to operate at a constant current output at the resonant frequency point to ignite the reaction chamber, including: Controlling the introduction of exciting gas; At the first preset time before the ignition operation, the resonant output current reference value Instantly reduce to the current reference value ; When receiving the ignition signal, the relay S is driven to close, otherwise the system continues to pass the excitation gas; The resonant output current reference value The current value sampled by the power circuit Output current error after comparison , after current PI modulation, the PWM drive unit is started; Determine whether it is satisfied And it is maintained for more than the second preset time. If it is satisfied, then it is determined whether the system is ignited successfully. Otherwise, it is ignition failure, the system reports an error and disconnects the relay S; If it is determined that the ignition is abnormal, the plasma ignition duration and ignition voltage are adaptively adjusted, and the ignition duration and ignition voltage are amplified by a ratio of (1+K) and cyclically processed; If the ignition fails after exceeding the cycle upper limit, it is judged as an ignition failure, the system reports an error and disconnects the relay; when the ignition is successful, the relay is disconnected, the constant current stage ends and the constant power stage begins.

8. A remote plasma source fuzzy hysteresis control circuit, characterized in that: A remote plasma source fuzzy hysteresis control method using any one of claims 1 to 7, comprising a control unit, a PWM drive unit, a resonant converter, an ignition circuit, a sampling unit, a relay and a reaction chamber; The control unit is used to control the PWM drive unit to output a pulse signal and control the relay to be closed or disconnected; The resonant converter converts the pulse signal output by the PWM drive unit into an AC source, and is used to provide an input AC source for the ignition circuit; The ignition circuit generates a high-voltage ignition signal to cause the plasma load in the reaction chamber to oscillate and ionize at a high frequency; The sampling unit is used to collect the ignition current of the ignition circuit, and the output voltage and output current of the resonant converter; The resonant converter includes a transformer T1, and the ignition circuit is connected to a secondary coil N3 of the transformer T1; The relay is controlled by the control unit to be closed or disconnected.

9. The circuit according to claim 8, characterized in that The maintenance circuit is also included. The maintenance circuit is connected in series with the secondary coil N2 of the transformer T1, and the reaction cavity is used as the secondary side of the transformer T1 to provide only , to meet the low-voltage energy input in the constant power stage; The maintaining circuit is used to maintain the bus voltage stable after entering the constant power stage from the constant current stage when the relay is disconnected.

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