A remote plasma source power coupling circuit and control system

Abstract

The present invention belongs to the field of semiconductor manufacturing technology and provides a remote plasma source power coupling circuit and control system, including a DC voltage source, two parallel current sharing circuits, a three-winding transformer and a cavity load, wherein the current sharing circuit includes a full-bridge inverter circuit, a resonant converter, a current sharing resistor R o , the full-bridge inverter circuit inputs a DC voltage source; the resonant converter is connected to the full-bridge inverter circuit; the resonant converter includes an inductor L r , capacitor C r and inductor L k , inductance L r Connect the full-bridge inverter circuit, inductor L k Connect three-winding transformer; current-sharing resistor R o and inductor L k The primary winding coil of the three-winding transformer is connected to the two current-sharing circuits respectively, and the secondary winding coil is connected to the cavity load. The remote plasma source power coupling circuit provided by the present invention can improve the output power of the remote plasma source through the two current-sharing circuits of the transformer, and realize the effect of automatic current balancing of hardware through the transformer.

Description

Technical Field

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

[0002] A remote plasma source is a device for generating plasma, which is usually used in photovoltaic, chemical, semiconductor and other fields. In the prior art, in order to improve the cleaning efficiency of the system, the remote plasma source needs to introduce a higher flow of gas for reaction, so a higher power output is required; this embodiment uses a coupling transformer to connect multiple modular power supplies in parallel for high-power output. However, in the process of power boosting, the current sharing requirements for multiple circuit loads are high. At this time, if the system current sharing control is inaccurate, the load with a large output current will bear a large current stress, which may cause the system to crash. Therefore, how to ensure the consistency of the current sharing of each power module when the plasma source is in the process of power boosting has become a problem that needs to be solved urgently by those skilled in the art.

[0003] High-frequency power converters have been widely used in power supply systems. However, as the system capacity expands, centralized power supplies will have greater electrical stress, which will bring difficulties to the selection of power devices, switching frequency, heat dissipation design and the improvement of power density; and when the only power supply fails internally, it will cause the system to crash and reduce redundancy. Multiple small power modules can be connected in parallel to meet the needs of different loads by changing the number of parallel connections. The design is flexible and effectively improves the redundancy and reliability of the system.

[0004] The parallel connection of remote plasma source circuits brings about the current sharing problem between module power supplies. The parameter difference between parallel modules will lead to unreasonable current distribution between modules, which will cause the system to work in an extremely unstable state. Especially in low-voltage and high-current applications, slight parameter differences will also lead to large current imbalance. Therefore, the module parallel current sharing technology directly restricts the development of large-capacity modular power supply systems for remote plasma sources. The module parallel current sharing technology methods can be divided into external characteristic current sharing method and active current sharing method. The external characteristic current sharing method cannot take into account the load adjustment rate and current sharing accuracy, so it is not suitable for medium and large power occasions. The active current sharing method currently 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 are essentially master-slave control. The setting of the master module will reduce the redundancy and reliability of the entire system, while the automatic master-slave method will cause the system to respond slowly 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 balancing method does not require master-slave settings and has the advantages of fast response speed, high current balancing accuracy, and relatively simple control.

[0005] At present, in order to increase the power output, remote plasma sources usually adopt a circuit structure of dual-channel parallel module power supply. Due to the difference in impedance between the modules, the current distribution of the two outputs will be uneven, and the voltage of the current-sharing bus will drop, which will cause the voltage of the two modules of the parallel system to drop; thus, the load with a large output current will bear a large current stress, which may cause the system to crash. Therefore, how to ensure the consistency of the current sharing of each power module during the power increase of the plasma source has become an urgent problem to be solved in this field. Summary of the invention

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

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

[0008] Full-bridge inverter circuit, input DC voltage source;

[0009] A resonant converter is connected to the full-bridge inverter circuit; the resonant converter includes an inductor L r , capacitor C r and inductor L k , inductance L r Connect the full-bridge inverter circuit, inductor L k connecting the three-winding transformer;

[0010] Current sharing resistor R o , and the inductor L k connect;

[0011] The three-winding transformer has a primary coil connected to the two current-sharing circuits respectively, and a secondary coil connected to the cavity load.

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

[0013] In a second aspect, the present invention provides a remote plasma source power coupling control system, which is used for any possible form of remote plasma source power coupling circuit in the first aspect, including a power loop, a current loop and a current equalizing loop, wherein the power loop serves as an outer loop of the control system, the current equalizing loop acts simultaneously and in parallel with the power loop, and the current loop serves as an inner loop of the control system.

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

[0015] Collect the current sharing resistor R o The voltage across the terminals V a 、V b , respectively obtain the voltage error e r 、e r ';

[0016] Among them, if the output current i of the primary winding is o and i o ' are equal, then the voltage error e r 、e r ' are all zero, and the output of the current balancing loop is zero.

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

[0018] Collect the output voltage V of the two primary windings respectively o 、V o ' and output current i o 、i o ', get the output power P of the two primary windings o , P o ';

[0019] According to the preset reference power And the output power P o , P o ', get the power error e o 、e o ';

[0020] According to the power error e o 、e o 'Perform power loop PI regulation.

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

[0022] Get the output current reference value i adjusted by the power loop PI o1 、i o2 , and according to the current reference value i o1 、i o2 Determine the average filter value

[0023] According to the average filter value Output current i o 、i o ' and voltage error e r 、e r ', respectively obtain the current error e s 、e s ';

[0024] According to the current reference value i o1 、io2 , voltage error e r 、e r ' and average filtered value The current loop error e is obtained respectively o1 、e o2 ;

[0025] According to the current loop error e o1 、e o2 Perform current loop PI regulation.

[0026] Optionally, a controller and a PWM modulator are also included,

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

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

[0029] By adopting the above technical solution, the present application has the following beneficial effects:

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

[0031] The control system provided by the present invention utilizes a three-loop control strategy of a power loop, a current loop and a current equalizing 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 equalizing loop and the power loop act in parallel at the same time, so that the structure of the remote plasma source power coupling circuit is simple and the current equalizing effect is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] 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.

[0033] Figure 1 A schematic diagram of a remote plasma source power coupling circuit provided by an embodiment of the present invention is shown;

[0034] Figure 2 A schematic diagram of a magnetic core of a three-winding transformer provided in an embodiment of the present invention is shown;

[0035] Figure 3 A schematic diagram of a remote plasma source power coupling control system provided by an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0036] 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.

[0037] 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.

[0038] In one embodiment, Figure 1 As shown, a remote plasma source power coupling circuit is provided, including a DC voltage source, two parallel current balancing circuits, a three-winding transformer and a cavity load, the two current balancing circuits are the same, and the current balancing circuit includes a full-bridge inverter circuit, a resonant converter, and a current balancing resistor R o , the full-bridge inverter circuit inputs a DC voltage source; the resonant converter is connected to the full-bridge inverter circuit; the resonant converter includes an inductor L r , capacitor C r and inductor L k , inductance L r Connect the full-bridge inverter circuit, inductor L k Connect three-winding transformer; current-sharing resistor R o and inductor L k Connection: The primary winding coil of the three-winding transformer is connected to the two current-sharing circuits respectively, and the secondary winding coil is connected to the cavity load.

[0039] like Figure 2 As shown in (a), the core of the three-winding transformer is a T-type transformer core. The primary winding coil of the three-winding transformer is wound on the middle side of the T-type transformer core, and the secondary winding coil of the three-winding transformer is wound on both sides of the T-type transformer core. V1 and V2 are connected to the outputs of the two current-sharing circuits respectively, and V3 is the output voltage of the three-winding transformer. Figure 2 (b) shows the existing transformer structure, the transformer winding coil is wound on the middle side of the T-type transformer, and V3 is the output voltage. The three-winding transformer T1 is connected in parallel with two current-sharing circuits. The coupling coefficient is improved through the parameter design of the transformer turns ratio and the number of windings. It is easier to realize automatic current balancing between the two current-sharing circuits from the hardware level, which can play a role in improving the output power of the remote plasma source.

[0040] The remote plasma source power coupling circuit provided above can improve the output power of the remote plasma source by connecting two current-sharing circuits in parallel through a coupling transformer, and realize the effect of automatic current-sharing of hardware through the transformer. However, due to the inconsistency of the primary winding inductance, number of windings, coupling coefficient and other issues of each module, the current-sharing error of each module will be caused. Therefore, in one embodiment, Figure 3 As shown, a remote plasma source power coupling control system is also provided, which is used for the remote plasma source power coupling circuit provided in the above embodiment to ensure the consistency of the output current between the current balancing circuits. Figure 3 Taking one of the current balancing circuits as an example, for each current balancing circuit, the control system includes a power loop, a current loop and a current balancing loop. The power loop serves as the outer loop of the control system, the current balancing loop and the power loop act in parallel, and the current loop serves as the inner loop of the control system. The other current balancing circuit is arranged in the same way.

[0041] See also Figure 3 , the current equalizing ring is specifically used for:

[0042] Collect the current sharing resistor R o The voltage across the terminals V a 、V b , respectively obtain the voltage error e r 、e r ';

[0043] Among them, if the primary winding output current i of the two current balancing circuits is o and i o ' are equal, then the voltage error e r 、e r ' are all zero, and the output of the current sharing loop is zero.

[0044] The two current balancing circuits of the current balancing loop are respectively connected to the current balancing resistor R o , R' o After sampling the voltage at both ends, there is V b =V b ', the output voltage error e of the two current balancing circuits is compared by current balancing controllers U1 and U1' r 、e r ', the primary winding output current i of the two current balancing circuits o and i o ' is equal, the output voltage of the two current-sharing circuits is equal to the voltage signal on the current-sharing bus, and no current flows through the current-sharing resistors. Therefore, 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 output current i o and io ' is equal, that is, the voltage error e of the outputs of the two current equalizing controllers U1 and U1' r 、e r ' are all zero. In this embodiment, the control system realizes the consistency of the output current of the dual-path current balancing circuit through the three-loop control of the current balancing loop, the power loop and the current loop.

[0046] See also Figure 3 , the power ring is specifically used for:

[0047] Collect the output voltage V of the two primary windings respectively o 、V o ' and output current i o 、i o ', get the output power P of the two primary windings o , P o ';

[0048] According to the preset reference power And the output power P o , P o ', get the power error e o 、e o ';

[0049] According to the power error e o 、e o 'Perform power loop PI regulation.

[0050] See also Figure 3 , the current loop is specifically used for:

[0051] Get the output current reference value i adjusted by the power loop PI o1 、i o2 , and according to the current reference value i o1 、i o2 Determine the average filter value Average filtering value of two current balancing circuits

[0052] According to the average filter value Output current i o 、i o ' and voltage error e r 、e r ', respectively obtain the current error e s 、e s ';

[0053] According to the current reference value i o1 、i o2 , voltage error e r 、e r ' and average filtered value The current loop error e is obtained respectivelyo1 、e o2 ;

[0054] According to the current loop error e o1 、e o2 Perform current loop PI regulation.

[0055] In any current sharing circuit, V a is the current sharing bus voltage, V b It can be regarded as the average voltage signal of the dual parallel power supply. a and V b After comparison, the voltage error e is output through the current equalization controller U1. r ; The sampled module 1 output current i o The average filtered value of the output current of the two modules After comparison, the output voltage error e r Added as the output current error e s ; Set the output current reference value i of module 1 o1 The average filtered value of the output current of the two modules After comparison, the output current error e s Add the current loop error signal e o1 .

[0056] Optionally, it also includes a controller and a PWM modulator, the controller is used to obtain the switching frequency and duty cycle after current loop PI adjustment; the PWM modulator is used to control the output pulse signal to control the switching of the switch tubes S1-S4 according to the switching frequency and duty cycle.

[0057] Determine the current loop error e in the current loop o1 、e o2 After that, the current loop error is adjusted by PI to obtain the switching frequency f of each module. s And duty cycle d, finally the controller outputs the compensated control signal to the PWM modulator, the output pulse signal controls the on and off of the switch tubes S1-S4, and the full-bridge inverter circuit outputs the AC source.

[0058] The following Figure 3 The module 1 current sharing circuit shown in the figure is used as an example to illustrate the current loop error e o1 After current loop PI regulation, the output signal v fs , after being amplified and limited by K1, the frequency signal f of PWM modulator 1 is obtained s ; The current loop error e o1 After the current loop PI is adjusted and the inverse is taken, the output signal v is obtained d After amplification by K2 and limiting, the duty cycle signal d for controlling PWM modulator 1 is obtained, where the switching frequency f sThe control of the current sharing circuit of module 2 is similar to that of module 1.

[0059] 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 remote plasma source power coupling circuit, characterized in that: It includes a DC voltage source, two current balancing circuits connected in parallel, a three-winding transformer and a cavity load, wherein the current balancing circuit includes: Full-bridge inverter circuit, input DC voltage source; A resonant converter is connected to the full-bridge inverter circuit; the resonant converter includes an inductor ,capacitance and inductance ,inductance Connect the full-bridge inverter circuit, the inductor connecting the three-winding transformer; Current sharing resistor , and inductance connect; The three-winding transformer, the primary winding coil is connected to the two current-sharing circuits respectively, and the secondary winding coil is connected to the cavity load; The circuit is controlled by a control system, 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, the current sharing loop and the power loop act in parallel, and the current loop serves as the inner loop of the control system; The current loop is specifically used for: Get the output current reference value adjusted by the power loop PI , , and according to the current reference value , Determine the average filter value ; According to the average filter value , output current , and voltage error , , respectively obtain the current error , ; According to the current reference value , , voltage error , and average filtered value , respectively obtain the current loop error , ; According to the current loop error , Perform current loop PI regulation; Also includes controller and PWM modulator, The controller is used to obtain the switching frequency and duty cycle after the current loop PI adjustment; the current loop error Output signal after current loop PI adjustment , after amplification and limiting, the frequency signal of the PWM modulator is obtained ; The current loop error The output signal is obtained after the current loop PI adjustment and taking the inverse , after amplification and limiting, the duty cycle of the PWM modulator is obtained ; The PWM modulator is used to control the output pulse signal to control the switching of the switch tubes S1-S4 according to the switching frequency and the duty cycle.

2. The circuit according to claim 1, characterized in that 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. The system according to claim 1, characterized in that The current balancing ring is specifically used for: Collect the current sharing resistor The voltage across the , , respectively, to obtain the voltage error , ; Among them, if the output current of the primary winding and If the voltage error is equal , are all zero, and the output of the current balancing loop is zero.

4. The system according to claim 3, characterized in that The power ring is specifically used for: Collect the output voltage of the two primary windings respectively , and output current , , get the output power of two primary windings , ; According to the preset reference power and output power , , get the power error , ; According to the power error , Perform power loop PI regulation.

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