Power coupling circuit and control system for remote plasma source

Abstract

A power coupling circuit and control system for a remote plasma source. The circuit comprises a direct current voltage source Uin, two current equalizing circuits connected in parallel, a three-winding transformer T1, and a cavity load; each current equalizing circuit comprises a full bridge inverter circuit, a resonant converter, current equalizing resistors R0 and R'0; the full bridge inverter circuit inputs the direct current voltage source Uin; the resonant converter is connected to the full bridge inverter circuit; the resonant converter comprises inductors Lr and L'r, capacitors Cr and C'r, and inductors Lk and L'k; the inductors Lr and L'r are connected to the full bridge inverter circuit; the inductors Lk and L'k are connected to the three-winding transformer T1; the current equalizing resistors R0 and R'0 are connected to the inductors Lk and L'k; and a primary winding coil of the three-winding transformer T1 is separately connected to the two current equalizing circuits, and secondary winding coils are connected to the cavity load. In the power coupling circuit for a remote plasma source, output powers of the remote plasma source can be increased by means of two current equalizing circuits and a transformer, and the effect of automatic current equalizing of hardware is achieved by means of the transformer.

Description

Remote plasma source power coupling circuit and control system TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor manufacturing, in particular to a remote plasma source power coupling circuit and control system. BACKGROUND

[0002] The remote plasma source is a device for generating plasma, which is commonly used in the fields of photovoltaic, chemical industry, semiconductor, etc. In the prior art, in order to improve the cleaning efficiency of the system, a higher flow of gas needs to be introduced for reaction, so a higher power output is required. In the embodiment, a plurality of module power supplies are connected in parallel through a coupling transformer to realize high-power output. However, during the process of power improvement, the current sharing of the multiple circuit loads needs to be high. If the system current sharing control is not accurate, the load with a large output current will bear a large current stress, which may cause the system to collapse. Therefore, how to ensure the consistency of current sharing of each power module during the power improvement of the plasma source has become a problem to be solved by those skilled in the art.

[0003] High-frequency power converters have been widely used in power supply systems. However, with the expansion of system capacity, centralized power supply will bring large electrical stress, which will bring difficulties to the selection of power devices, switching frequency, heat dissipation design and the improvement of power density. Moreover, when there is an internal fault in the only power supply, it will lead to system collapse and reduce the redundancy. By changing the number of parallel connections, multiple small power modules in parallel can adapt to the needs of different loads, and the design is flexible, which effectively improves the system's redundancy and reliability.

[0004] With the parallel connection of the remote plasma source circuit, the current sharing problem between the module power supplies arises. The parameter difference between the parallel modules will cause unreasonable current distribution between the modules, and thus make the system work in a limit unstable state. Especially in low-voltage and high-current application occasions, slight parameter difference will also cause large current unbalance. Therefore, the module parallel current sharing technology directly restricts the development of the large-capacity modular power supply system of the remote plasma source. The module parallel current sharing technology can be divided into external characteristic current sharing method and active current sharing method. The external characteristic current sharing method cannot balance the load regulation rate and current sharing accuracy, and thus is not suitable for medium and high power occasions. The active current sharing method mainly includes master-slave current sharing method, external current sharing controller, maximum current sharing method and average current sharing method. The master-slave current sharing method and the maximum current sharing method essentially belong to master-slave control, and the setting of the master module will reduce the redundancy and reliability of the whole system. The automatic master-slave method leads to slow system response speed due to the switching of the master module. The external current sharing controller will greatly increase the complexity of the system, which is not conducive to practical application. The average current sharing method does not need master-slave setting, has fast response speed, high current sharing accuracy and relatively simple control, etc.

[0005] In order to improve the power output, the remote plasma source usually adopts a circuit structure of double parallel module power supply. Due to the impedance difference between the modules, the current distribution of the two outputs will be uneven, and the voltage of the current sharing bus will be reduced, which will cause the voltage of the two modules of the parallel system to be reduced; thereby causing the load with larger output current to bear larger current stress, which may cause the system to collapse. Therefore, how to ensure the consistency of current sharing of each power module in the process of power improvement of the plasma source has become a problem to be solved in the field. SUMMARY

[0006] In view of the defects in the prior art, the present application provides a remote plasma source power coupling circuit and control system to solve the problem of consistency of current sharing of each power module of the current remote plasma source.

[0007] In a first aspect, the present application provides a remote plasma source power coupling circuit, comprising a direct current source, two parallel current sharing circuits, a three-winding transformer and a cavity load, wherein the current sharing circuit comprises:

[0008] a full-bridge inverter circuit, an input direct current voltage source;

[0009] a resonant converter connected with the full-bridge inverter circuit; the resonant converter comprises an inductor , a capacitor and an inductor , an inductor connected with the full-bridge inverter circuit, an inductor connected with the three-winding transformer;

[0010] a current sharing resistor connected with an inductor ;

[0011] the three-winding transformer, the primary coil is connected with the two current sharing circuits respectively, and the secondary coil is connected with the cavity load.

[0012] Optionally, the magnetic core of the three-winding transformer is a T-shaped transformer magnetic core, the primary winding coil of the three-winding transformer is wound on the middle side of the T-shaped transformer magnetic core, and the secondary winding coil of the three-winding transformer is wound on both sides of the T-shaped transformer magnetic core.

[0013] In a second aspect, the present application provides a remote plasma source power coupling control system for any possible form of the remote plasma source power coupling circuit of the first aspect, comprising a power ring, a current ring and a current sharing ring, wherein the power ring serves as an outer ring of the control system, the current sharing ring and the power ring act simultaneously and in parallel, and the current ring serves as an inner ring of the control system.

[0014] Optionally, the current sharing ring is specifically used for:

[0015] Collect the current sharing resistance voltage across the two ends , The voltage error was obtained respectively. , ;

[0016] Among them, if the output current of the primary winding and If they are equal, then the voltage error is... , All values ​​are zero, and the output of the current sharing ring is zero.

[0017] Optionally, the power loop is specifically used for:

[0018] The output voltages of the two primary windings were collected separately. , and output current , To obtain the output power of the two primary windings , ;

[0019] According to the preset reference power and output power , Obtain power error , ;

[0020] According to power error , Perform power loop PI regulation.

[0021] Optionally, the current loop is specifically used for:

[0022] Obtain the reference value of the output current regulated by the power loop PI. , And according to the current reference value , Determine the average filter value ;

[0023] Based on average filter value Output current , and voltage error , The current error was obtained respectively. , ;

[0024] According to the current reference value , voltage error , and average filter value , respectively obtain current loop error , ;

[0025] According to the current loop error , The current loop PI regulation is carried out.

[0026] Optionally, further comprising a controller and a PWM modulator,

[0027] The controller is used to obtain the switching frequency and duty cycle after current loop PI regulation;

[0028] The PWM modulator is used to control the output pulse signal to control the on-off of the switching tube S1-S4 according to the switching frequency and duty cycle.

[0029] With the above technical solution, the application has the following beneficial effects:

[0030] The remote plasma source power coupling circuit provided by the application can improve the output power of the remote plasma source through the two-way current sharing circuit of the transformer, and realize the effect of automatic current sharing of the hardware through the transformer;

[0031] The control system provided by the application uses the three-loop control strategy of the power loop, the current loop and the current sharing loop, wherein the power loop serves as the outer loop of the control system, the current loop serves as the inner loop of the control system, and the current sharing loop and the power loop act simultaneously and in parallel, so that the structure of the remote plasma source power coupling circuit is simple and the current sharing effect is good. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the specific embodiments or prior art, the drawings needed to be used in the specific embodiments or prior art description will be briefly introduced below. 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 proportions.

[0033] Fig. 1 shows a schematic diagram of a remote plasma source power coupling circuit according to an embodiment of the application;

[0034] Fig. 2 shows a schematic diagram of a magnetic core of a three-winding transformer according to an embodiment of the application;

[0035] Fig. 3 shows a schematic diagram of a remote plasma source power coupling control system according to an embodiment of the application. Embodiments of the application

[0036] The embodiments of the technical solutions of the present application will be described in detail below with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0037] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in the present application should be understood as the usual meanings understood by the skilled person in the field to which the present application belongs.

[0038] In one embodiment, as shown in FIG. 1, a remote plasma source power coupling circuit is provided, including a direct current voltage source, two parallelly connected current sharing circuits, a three-winding transformer and a cavity load, the two current sharing circuits are the same, and the current sharing circuit includes a full-bridge inverter circuit, a resonant converter, a current sharing resistor , the full-bridge inverter circuit inputs the direct current voltage source; the resonant converter is connected with the full-bridge inverter circuit; the resonant converter includes an inductor , a capacitor and an inductor , the inductor is connected with the full-bridge inverter circuit, and the inductor is connected with the three-winding transformer; the current sharing resistor and the inductor are connected; the primary winding coil of the three-winding transformer is connected with the two current sharing circuits respectively, and the secondary winding coil is connected with the cavity load.

[0039] As shown in FIG. 2(a), the magnetic core of the three-winding transformer is a T-shaped transformer magnetic core, the primary winding coil of the three-winding transformer is wound on the middle side of the T-shaped transformer magnetic core, and the secondary winding coil of the three-winding transformer is wound on both sides of the T-shaped transformer magnetic core. 、 respectively connected with the outputs of the two current sharing circuits, is the output voltage of the three-winding transformer. As shown in FIG. 2(b), it is the existing transformer structure, the winding coil of the transformer is wound on the middle side of the T-shaped transformer, is the output voltage. The three-winding transformer T1 is connected in parallel through the two current sharing circuits, and through the parameter design of the transformer turn ratio and the winding number, the coupling coefficient is improved, the automatic current sharing between the two current sharing circuits is more easily realized from the hardware level, and the output power of the remote plasma source can be improved.

[0040] The remote plasma source power coupling circuit described above connects two current-sharing circuits in parallel via a coupling transformer, which can improve the output power of the remote plasma source and achieve automatic current sharing through the transformer. However, due to inconsistencies in the inductance, number of turns, and coupling coefficients of the primary windings of each module, errors in the current sharing of each module can occur. Therefore, in one embodiment, as shown in Figure 3, a remote plasma source power coupling control system is also provided for the remote plasma source power coupling circuit provided in the aforementioned embodiment to ensure the consistency of the output current between the current-sharing circuits. Figure 3 specifically uses one current-sharing circuit as an example. For each current-sharing circuit, the control system includes a power loop, a current loop, and a current-sharing loop. The power loop serves as the outer loop of the control system, and the current-sharing loop operates in parallel with the power loop. The current loop serves as the inner loop of the control system. The other current-sharing circuit is arranged in the same manner.

[0041] Referring to Figure 3, the flow equalization ring is specifically used for:

[0042] Collect current sharing resistance voltage across the two ends , The voltage error was obtained respectively. , ;

[0043] Among them, if the primary winding output current of the two current sharing circuits and If they are equal, then the voltage error is... , All values ​​are zero, and the output of the current sharing loop is zero.

[0044] The two current sharing circuits of the current sharing ring respectively connect to the current sharing resistor. , After sampling the voltage at both ends, there exists The output voltage error of the two current sharing circuits is compared by the current sharing controllers U1 and U1'. , The primary winding output current of the two current-sharing circuits and When the current sharing circuits are equal, the output voltage of the two current sharing circuits and the voltage signal on the current sharing bus are equal. No current flows through the current sharing resistors, so the output of the current sharing loop is zero. At this time, the three-loop control can be simplified to two-loop control, and the current sharing loop does not participate in the control.

[0045] Specifically, the control system tracks and controls the output current of module 1 and module 2 respectively, in order to achieve the desired output current of the two modules. and Equal, meaning the voltage error output by the two current sharing controllers U1 and U1' is equal. , Both are zero. In this embodiment, the control system achieves consistent output current of the dual current sharing circuits through three-loop control: current sharing loop, power loop, and current loop.

[0046] Referring to Figure 3, the power loop is specifically used for:

[0047] The output voltages of the two primary windings were collected separately. , and output current , To obtain the output power of the two primary windings , ;

[0048] According to the preset reference power and output power , Obtain power error , ;

[0049] According to power error , Perform power loop PI regulation.

[0050] Referring to Figure 3, the current loop is specifically used for:

[0051] Obtain the reference value of the output current regulated by the power loop PI. , And according to the current reference value , Determine the average filter value The average filter value of the two current sharing circuits ;

[0052] Based on average filter value Output current , and voltage error , The current error was obtained respectively. , ;

[0053] According to the current reference value , Voltage error , and average filter value The current loop error was obtained respectively. , ;

[0054] Based on current loop error , Perform current loop PI regulation.

[0055] In any current sharing circuit, This is the current-sharing bus voltage. It can be viewed as the average voltage signal of the dual parallel power supply, in relation to and After comparison, the voltage error is output through the current sharing controller U1. The sampled output current of module 1 The average filtered value of the output current of the two modules After comparison, the error with the output voltage is... Added as output current error ; Set the output current reference value of module 1 The average filtered value of the output current of the two modules After comparison, the error with the output current The summation yields the current loop error signal. .

[0056] Optionally, it also includes a controller and a PWM modulator. The controller is used to obtain the switching frequency and duty cycle after PI regulation by the current loop; the PWM modulator is used to control the switching transistors S1-S4 to turn on and off according to the switching frequency and duty cycle by controlling the output pulse signal.

[0057] Determine the current loop error in the current loop. , Then, the switching frequency of each module is obtained by adjusting the current loop error using a PI controller. and duty cycle Finally, the controller outputs the compensated control signal to the PWM modulator, which outputs pulse signals to control the switching on and off of the switching transistors S1-S4, and the full-bridge inverter circuit outputs an AC source.

[0058] The following explanation uses the current sharing circuit of module 1 shown in Figure 3 as an example to illustrate the current loop error. Output signal after PI regulation by current loop After being amplified and limited by K1, the frequency signal of PWM modulator 1 is obtained. ; Current loop error The output signal is obtained after PI regulation by the current loop and taking the reciprocal. After being amplified and limited by K2, the duty cycle signal controlling PWM modulator 1 is obtained. The switching frequency and duty cycle signal They are inversely proportional; finally, PWM modulator 1 will control the pulse signal. The output is given to the switching tubes S1-S4. The control of the current sharing circuit of module 2 is similar to module 1.

[0059] The above embodiments are only used to describe the technical solutions of the present application in detail, but the above descriptions are only used to help understand the method of the embodiments of the present application, and should not be construed as a limitation to the embodiments of the present application. Changes or replacements that can be easily thought of by those skilled in the art should be covered within the protection scope of the embodiments of the present application.

Claims

1. A remote plasma source power coupling circuit, comprising: The circuit comprises a direct current voltage source, two parallel current sharing circuits, a three-winding transformer and a cavity load, wherein the current sharing circuit comprises: a full-bridge inverter circuit, an input direct current voltage source; a resonant converter, connected to the full-bridge inverter circuit; the resonant converter comprises an inductor capacitor and inductance inductance connecting the full-bridge inverter circuit, an inductor connecting the three-winding transformer; Current sharing resistors , and inductance connecting; the three-winding transformer, the primary winding coils are connected with the two current sharing circuits respectively, and the secondary winding coil is connected with the cavity load.

2. The circuit of claim 1, wherein, The magnetic core of the three-winding transformer is a T-shaped transformer magnetic core, the primary winding coil of the three-winding transformer is wound on the middle side of the T-shaped transformer magnetic core, and the secondary winding coil of the three-winding transformer is wound on both sides of the T-shaped transformer magnetic core.

3. A remote plasma source power coupling control system, characterized by, The circuit according to any one of claims 1-2, comprising a power ring, a current ring and a current sharing ring, the power ring serving as an outer ring of a control system, the current sharing ring acting simultaneously and in parallel with the power ring, and the current ring serving as an inner ring of the control system.

4. The system of claim 3, wherein, The current sharing ring is specifically used for: collecting the current-sharing resistor voltage across the ends of the capacitor 、 , respectively, to obtain voltage errors 、 ； wherein, if the output current of the primary winding is and equal, then the voltage error 、 all being zero, and the output of the current sharing ring being zero.

5. The system of claim 4, wherein, The power ring is specifically used for: Collecting output voltages of two primary windings respectively 、 and output current 、 , obtaining the output power of two primary windings 、 ； According to a predetermined reference power and output power 、 , obtain power error 、 ； According to the power error 、 performing power ring PI regulation.

6. The system of claim 5, wherein, The current ring is specifically used for: Obtaining a power loop pi regulated output current reference value 、 and according to the current reference value 、 determining an average filter value ； According to the average filter value , output current 、 and voltage error 、 , respectively, to obtain current error 、 ； According to the current reference value 、 voltage error 、 and average filter value , the current loop error 、 ； According to the current loop error 、 performing current ring PI regulation.

7. The system of claim 6, wherein, The circuit further comprises a controller and a PWM modulator, the controller is used for acquiring the switching frequency and the duty cycle after current ring PI regulation; the PWM modulator is used for controlling the output pulse signal to control the on-off of the switching tubes S1-S4 according to the switching frequency and the duty cycle.

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