Impedance matcher and plasma generation equipment

Abstract

The utility model discloses an impedance matcher and plasma generation equipment, and belongs to the field of impedance matching, and the impedance matcher comprises a main control circuit; the detection end of the voltage detection circuit is electrically connected with the output end of the radio frequency power supply, and the output end of the voltage detection circuit is electrically connected with the signal receiving end of the main control circuit; the controlled ends of the plurality of switch circuits are electrically connected with the control end of the main control circuit; the output end of the radio frequency power supply is electrically connected with the first ends of the impedance matching circuits, the second ends of the impedance matching circuits are electrically connected with the input ends of the switching circuits in a one-to-one correspondence manner, and the output ends of the switching circuits are electrically connected with the electrodes of the plasma chamber; the utility model aims to solve the problem that the response speed of the existing impedance matcher is not enough to quickly adapt to the large-amplitude impedance change of a plasma chamber.

Description

Technical Field

[0001] The utility model relates to the technical field of impedance matching, in particular to an impedance matcher and plasma generating equipment. Background Art

[0002] The impedance of the nonlinear load in the plasma chamber is not equal to the constant output impedance of the RF power supply. Therefore, there is a serious impedance mismatch between the RF power supply and the plasma chamber, resulting in a large amount of reflected power on the transmission line. The power generated by the RF power supply cannot be fully transmitted to the plasma chamber, resulting in a large power loss.

[0003] To solve this problem, the impedance matching network in the RF power supply system is adjusted so that the sum of the impedance of the impedance matching network and the impedance of the nonlinear load in the plasma chamber is equal to the impedance of the RF power supply, thereby achieving impedance matching and achieving maximum output power.

[0004] However, when the output power or frequency band of the plasma chamber is adjusted significantly, the density and distribution of the plasma in the plasma chamber will change significantly, resulting in a large change in the impedance of the plasma chamber. If the impedance matching circuit has a relatively small adjustment range at this time, its response speed will not be fast enough to quickly adapt to this large impedance change, resulting in a decrease in the power transmission efficiency of the RF power supply. Utility Model Content

[0005] The main purpose of the utility model is to provide an impedance matcher and a plasma generating device, aiming to solve the problem that the response speed of the existing impedance matcher is not fast enough to quickly adapt to the large impedance changes of the plasma chamber.

[0006] To achieve the above-mentioned object, the present invention proposes an impedance matcher, which is applied to a plasma generating device. The plasma generating device includes a radio frequency power supply and a plasma chamber. The radio frequency power supply outputs radio frequency energy to the plasma chamber through the impedance matcher. The impedance matcher is characterized in that the impedance matcher includes:

[0007] Main control circuit;

[0008] a voltage detection circuit, wherein a detection end of the voltage detection circuit is electrically connected to the output end of the RF power supply, the voltage detection circuit is used to detect the output voltage of the RF power supply, and the output end of the voltage detection circuit is electrically connected to the signal receiving end of the main control circuit;

[0009] A plurality of switch circuits, wherein the controlled ends of the plurality of switch circuits are electrically connected to the control end of the main control circuit;

[0010] a plurality of impedance matching circuits, wherein the output end of the RF power supply is electrically connected to the first ends of the plurality of impedance matching circuits, the second ends of the plurality of impedance matching circuits are electrically connected to the input ends of the plurality of switch circuits in a one-to-one correspondence, the output ends of the plurality of switch circuits are electrically connected to the electrodes of the plasma chamber, and the controlled ends of the plurality of impedance matching circuits are electrically connected to the control end of the main control circuit; wherein the equivalent impedances of the plurality of impedance matching circuits are different;

[0011] When the output voltage of the RF power supply reaches one of a plurality of preset voltage thresholds, the main control circuit controls the corresponding switch circuit to be turned on, and controls the other switch circuits to be turned off.

[0012] In one embodiment, the main control circuit includes:

[0013] Multiple comparator circuits, multiple reference source circuits and a main control module, the inverting ends of the multiple comparator circuits are connected to the multiple reference source circuits, the non-inverting ends of the multiple comparator circuits are electrically connected to the output end of the voltage detection circuit, and the output ends of the multiple comparator circuits are electrically connected to the signal receiving end of the main control module.

[0014] In one embodiment, the reference source circuit includes:

[0015] A multiplexer and a resistor string, one end of the resistor string is connected to a first current, and the other end of the resistor string is grounded. The resistor string includes a plurality of first resistors electrically connected in sequence, each first resistor having a first end connected to the first current, and the first ends of the plurality of first resistors are electrically connected to the multiplexer. The output end of the multiplexer is electrically connected to the inverting end of the corresponding comparator circuit. The multiplexer includes a first signal receiving end, and the first signal receiving end is electrically connected to the control end of the main control module.

[0016] In one embodiment, the switching circuit includes:

[0017] A first switching tube, wherein the input end of the first switching tube is electrically connected to the first end of the impedance matching circuit, the output end of the first switching tube is electrically connected to the electrode of the plasma chamber, and the controlled end of the first switching tube is electrically connected to the control end of the main control circuit.

[0018] In one embodiment, the impedance matching circuit includes:

[0019] A first inductor, a second inductor and a first capacitor, wherein the first end of the first inductor is electrically connected to the output end of the RF power supply, the second end of the first inductor is electrically connected to the first end of the second inductor and the second end of the first capacitor respectively, the second end of the second inductor is electrically connected to the electrode of the plasma chamber, and the second end of the first capacitor is grounded; wherein the first inductor, the second inductor and the first capacitor are all impedance-adjustable devices, and the controlled end of the first inductor, the controlled end of the second inductor and the controlled end of the first capacitor are all electrically connected to the control end of the main control circuit.

[0020] In one embodiment, the voltage detection circuit includes:

[0021] a second resistor, a third resistor and a photoelectric coupler, wherein the first end of the second resistor is electrically connected to the output end of the radio frequency power supply, the second end of the second resistor is electrically connected to the anode of the photodiode of the photoelectric coupler, the cathode of the photodiode of the photoelectric coupler is grounded, the input end of the phototransistor of the photoelectric coupler is connected to the first voltage, the output end of the phototransistor of the photocoupler is electrically connected to the signal receiving end of the main control circuit and the first end of the third resistor respectively, and the second end of the third resistor is grounded.

[0022] In one embodiment, the voltage detection circuit further includes:

[0023] A filter circuit, wherein an input end of the filter circuit is electrically connected to the first end of the third resistor, and an output end of the filter circuit is electrically connected to the signal receiving end of the main control circuit.

[0024] In one embodiment, the comparator circuit includes:

[0025] A first comparator and amplifier circuit, wherein the inverting end of the first comparator is connected to the reference source circuit, the non-inverting end of the first comparator is electrically connected to the output end of the voltage detection circuit, the output end of the first comparator is electrically connected to the input end of the amplifier circuit, and the output end of the amplifier circuit is electrically connected to the signal receiving end of the main control module.

[0026] The present invention also provides a plasma generating device, comprising a radio frequency power supply, a plasma chamber and any one of the impedance matching devices described above.

[0027] The technical solution of the present invention includes a voltage detection circuit, multiple impedance matching circuits and multiple switching circuits. Since the output voltage of the radio frequency power supply increases when the power or frequency band of the plasma chamber increases, the output voltage of the radio frequency power supply is detected by the voltage detection circuit so that the main control circuit can obtain the change of the power or frequency band of the plasma chamber. The multiple impedance matching circuits are electrically connected to the electrodes of the plasma chamber through multiple switching circuits. The equivalent impedances of the multiple impedance matching circuits are different. When the output voltage of the radio frequency power supply is greater than one of multiple preset voltage thresholds, the main control circuit controls the corresponding switching circuit to turn on and controls the other switching circuits to turn off.

[0028] With such a configuration, when the adjustment range of the power or frequency band of the plasma chamber is large, the impedance matcher of the present invention will switch the impedance matching circuit corresponding to the equivalent impedance according to the output voltage of the RF power supply, so that the impedance matching circuit can complete the impedance matching in a short time, avoiding the situation where the power transmission efficiency of the RF power supply is reduced due to insufficient response speed to quickly adapt to the large impedance changes of the plasma chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0030] Figure 1 This is a schematic diagram of a module according to an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of a module of another embodiment of the present utility model;

[0032] Figure 3 This is a schematic diagram of the circuit structure of an embodiment of the present utility model;

[0033] Figure 4 This is a schematic diagram of the circuit structure of another embodiment of the present utility model;

[0034] Figure 5 This is a schematic diagram of the circuit structure of yet another embodiment of the present invention.

[0035] Description of Figure Numbers:

[0036] 10. Main control circuit; 11. Comparator circuit; 12. Main control module; 13. Reference source circuit; 20. Voltage detection circuit; 30. Switch circuit; 40. Impedance matching circuit.

[0037] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0039] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0040] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0041] The impedance of the nonlinear load in the plasma chamber is not equal to the constant output impedance of the RF power supply. Therefore, there is a serious impedance mismatch between the RF power supply and the plasma chamber, resulting in a large amount of reflected power on the transmission line. The power generated by the RF power supply cannot be fully transmitted to the plasma chamber, resulting in a large power loss.

[0042] To solve this problem, the impedance matching network in the RF power supply system is adjusted so that the sum of the impedance of the impedance matching network and the impedance of the nonlinear load in the plasma chamber is equal to the impedance of the RF power supply, thereby achieving impedance matching and achieving maximum output power.

[0043] However, when the output power or frequency band of the plasma chamber is adjusted significantly, the density and distribution of the plasma in the plasma chamber will change significantly, resulting in a large change in the impedance of the plasma chamber. If the impedance matching circuit has a relatively small adjustment range at this time, its response speed will not be fast enough to quickly adapt to this large impedance change, resulting in a decrease in the power transmission efficiency of the RF power supply.

[0044] Therefore, the main purpose of the present invention is to provide an impedance matcher and a plasma generating device, aiming to solve the problem that the response speed of the existing impedance matcher is not fast enough to quickly adapt to the large impedance changes of the plasma chamber.

[0045] refer to Figure 1 The utility model proposes an impedance matcher, which is applied to a plasma generating device. The plasma generating device includes a radio frequency power supply and a plasma chamber. The radio frequency power supply outputs radio frequency energy to the plasma chamber through the impedance matcher. The impedance matcher includes:

[0046] Main control circuit 10;

[0047] A voltage detection circuit 20, wherein the detection end of the voltage detection circuit 20 is electrically connected to the output end of the RF power supply, the voltage detection circuit 20 is used to detect the output voltage of the RF power supply, and the output end of the voltage detection circuit 20 is electrically connected to the signal receiving end of the main control circuit 10;

[0048] A plurality of switch circuits 30, wherein the controlled ends of the plurality of switch circuits 30 are electrically connected to the control end of the main control circuit 10;

[0049] Multiple impedance matching circuits 40, wherein the output end of the RF power supply is electrically connected to the first ends of the multiple impedance matching circuits 40, the second ends of the multiple impedance matching circuits 40 are electrically connected to the input ends of the multiple switch circuits 30 in a one-to-one correspondence, the output ends of the multiple switch circuits 30 are electrically connected to the electrodes of the plasma chamber, and the controlled ends of the multiple impedance matching circuits 40 are electrically connected to the control end of the main control circuit 10; wherein the equivalent impedances of the multiple impedance matching circuits 40 are different;

[0050] When the output voltage of the RF power source reaches one of a plurality of preset voltage thresholds, the main control circuit 10 controls the corresponding switch circuit 30 to be turned on, and controls the other switch circuits 30 to be turned off.

[0051] In this embodiment, the main control circuit 10 can be implemented by a main controller, such as an MCU (Microcontroller Unit), a DSP (Digital Signal Process), an FPGA (Field Programmable Gate Array), a SOC (System On Chip), etc.

[0052] In this embodiment, the switch circuit 30 can be implemented using at least one switching transistor, such as a MOS transistor, an IGBT transistor, a thyristor, a triode, a power transistor, etc., and / or at least one switching device, such as a contactor, a circuit breaker, and a relay. When the main control circuit 10 turns on one of the switch circuits 30, the RF power supply outputs current to the plasma chamber via the corresponding impedance matching circuit 40.

[0053] In this embodiment, the voltage detection circuit 20 may be any one of a voltage transformer, a Hall voltage sensor or a resistance voltage divider.

[0054] In this embodiment, the impedance matching circuit 40 can adopt one of an L-type impedance matching circuit, a T-type impedance matching circuit or a Π-type impedance matching circuit. The L-type matching circuit is usually composed of an inductor and a capacitor, and these two elements can be connected in series or in parallel; the T-type network impedance matching circuit is composed of two inductors connected in series and two capacitors connected in parallel; the Π-type network impedance matching circuit is composed of two capacitors connected in parallel and two inductors connected in series. By adjusting the values ​​of the inductor and the capacitor, the impedance of the signal source and the impedance of the load can be converted into matching impedances, thereby achieving maximum power transmission and minimum reflection loss.

[0055] Specifically, the technical solution of the present invention includes a voltage detection circuit 20, multiple impedance matching circuits 40 and multiple switching circuits 30. Since the output voltage of the RF power supply increases when the power or frequency band of the plasma chamber increases, the output voltage of the RF power supply is detected by the voltage detection circuit 20 so that the main control circuit 10 can obtain the change in the power or frequency band of the plasma chamber. The multiple impedance matching circuits 40 are electrically connected to the electrodes of the plasma chamber through the multiple switching circuits 30. The equivalent impedances of the multiple impedance matching circuits 40 are different. When the output voltage of the RF power supply is greater than one of the multiple preset voltage thresholds, the main control circuit 10 controls the corresponding switching circuit 30 to turn on and controls the other switching circuits 30 to turn off.

[0056] With such a configuration, when the adjustment range of the power or frequency band of the plasma chamber is large, the impedance matcher of the present invention will determine the power or frequency band of the plasma chamber according to the output voltage of the RF power supply, and switch the impedance matching circuit 40 of the corresponding equivalent impedance, so that the impedance matching circuit 40 can complete the impedance matching in a short time, thereby avoiding the situation where the power transmission efficiency of the RF power supply is reduced due to insufficient response speed to quickly adapt to the large impedance change of the plasma chamber.

[0057] refer to Figure 2 In one embodiment of the present invention, the main control circuit 10 includes:

[0058] Multiple comparator circuits 11, multiple reference source circuits 13 and a main control module 12, the inverting ends of the multiple comparator circuits 11 are connected to the multiple reference source circuits 13, the non-inverting ends of the multiple comparator circuits 11 are electrically connected to the output end of the voltage detection circuit 20, and the output ends of the multiple comparator circuits 11 are electrically connected to the signal receiving end of the main control module 12.

[0059] In this embodiment, the comparator circuit 11 uses at least one comparator, and multiple reference source circuits 13 are respectively used to provide multiple preset voltage thresholds. When the output voltage of the RF power supply is greater than one of the preset voltage values, at least one comparator circuit 11 outputs a high level to the main control module 12. The main control module 12 controls the corresponding switch circuit 30 to turn on and controls other switch circuits 30 to turn off according to the number of high levels received.

[0060] For example, when the number of comparator circuits 11 and impedance matching circuits 40 is three, the equivalent resistance of the impedance matching circuits 40 increases from the first to the third. If the power or frequency band of the plasma chamber is adjusted to the maximum level, the voltage output by the RF power supply also increases to the maximum level accordingly. At this time, the voltage output by the RF power supply is greater than the voltage output by the multiple reference source circuits 13, so that all three comparator circuits 11 output a high level. When the main control module 12 receives three high-level signals, the main control module 12 controls the third switch circuit 30 to conduct, so that the RF power supply outputs current to the plasma chamber through the third impedance matching circuit 40, wherein the equivalent impedance of the third impedance matching circuit 40 is the largest. With this configuration, when the power or frequency band of the plasma chamber is adjusted to a large range, the impedance matching device of the present invention will determine the power or frequency band of the plasma chamber based on the output voltage of the RF power supply and switch the impedance matching circuit 40 with the corresponding equivalent impedance, so that the impedance matching circuit 40 can complete impedance matching in a short time, avoiding the situation where the power transmission efficiency of the RF power supply is reduced due to insufficient response speed to quickly adapt to the large impedance change of the plasma chamber.

[0061] It can be understood that when the number of high levels received by the main control module 12 is 2, the main control module 12 controls the corresponding switch circuit 30 to be turned on, so that the RF power supply outputs current to the plasma chamber through the second impedance matching circuit 40; when the number of high levels received by the main control module 12 is 1 or 0, the main control module 12 controls the corresponding switch circuit 30 to be turned on, so that the RF power supply outputs current to the plasma chamber through the first impedance matching circuit 40.

[0062] refer to Figure 3 In this embodiment, the reference source circuit 13 includes:

[0063] A multiplexer and a resistor string, one end of the resistor string is connected to the first current, and the other end of the resistor string is grounded. The resistor string includes multiple first resistors R1 electrically connected in sequence, each first resistor R1 has a first end connected to the first current, and the first ends of the multiple first resistors R1 are all electrically connected to the multiplexer. The output end of the multiplexer is electrically connected to the inverting end of the corresponding comparator circuit 11. The multiplexer includes a first signal receiving end, and the first signal receiving end is electrically connected to the control end of the main control module 12.

[0064] Since the resistor string is formed by connecting multiple first resistors R1 in series, the voltage of the first first resistor R1 to the voltage of the last first resistor R1 are in an equidistant relationship. The main control module 12 controls the multiplexer by outputting a corresponding control signal so that the multiplexer is electrically connected to the first end of the corresponding first resistor R1. The main control module 12 obtains the voltage of the first resistor R1 through the multiplexer. With this setting, the user can set the main control module 12 to output a corresponding control signal to control the multiplexer to access the first end of one of the resistors, thereby obtaining the required voltage value. Since the multiple voltages obtained are in an equidistant relationship with each other, the preset voltage threshold provided to the comparator circuit 11 is more accurate. In actual applications, assuming that the number of first resistors R1 is 3, the resistance of the first first resistor R1 is R, and the magnitude of the first current is I, the user can set the main control module 12 to output a coded signal 10 to the multiplexer so that the main control module 12 is electrically connected to the first end of the second first resistor R1 through the multiplexer. , thereby obtaining the upper limit threshold signal, that is, the voltage value 2IR of the second first resistor R1. Similarly, when the main control module 12 outputs the coded signal 01 or 11 to the multiplexer, so that the main control module 12 is electrically connected to the first end of the first first resistor R1 or the first end of the third first resistor R1 through the multiplexer, thereby obtaining the upper limit threshold signal, that is, the voltage value 3IR of the first first resistor R1 or the voltage value IR of the third first resistor R1. In this way, the user can set the voltages output by multiple reference source circuits 13 according to actual needs, thereby connecting different preset voltage thresholds to the multiple comparator circuits 11.

[0065] refer to Figure 2 In this embodiment, the comparator circuit 11 includes:

[0066] The first comparator U1 and the amplifier circuit, the inverting end of the first comparator U1 is connected to the reference source circuit 13, the non-inverting end of the first comparator U1 is electrically connected to the output end of the voltage detection circuit 20, the output end of the first comparator U1 is electrically connected to the input end of the amplifier circuit, and the output end of the amplifier circuit is electrically connected to the signal receiving end of the main control module 12.

[0067] The amplifier circuit is used to amplify the high level voltage output by the first comparator U1 to the operating voltage of the main control module 12 , so that the main control module 12 can recognize the high level output by the first comparator U1 .

[0068] refer to Figure 4 , the impedance matching circuit 40 includes:

[0069] A first inductor L1, a second inductor L2 and a first capacitor C1, wherein the first end of the first inductor L1 is electrically connected to the output end of the RF power supply, the second end of the first inductor L1 is electrically connected to the first end of the second inductor L2 and the second end of the first capacitor C1 respectively, the second end of the second inductor L2 is electrically connected to the electrode of the plasma chamber, and the second end of the first capacitor C1 is grounded; wherein the first inductor L1, the second inductor L2 and the first capacitor C1 are all impedance-adjustable devices, and the controlled end of the first inductor L1, the controlled end of the second inductor L2 and the controlled end of the first capacitor C1 are all electrically connected to the control end of the main control circuit 10.

[0070] In this embodiment, the first inductor L1, the second inductor L2 and the first capacitor C1 are all impedance-adjustable devices. The impedance of the first inductor L1, the impedance of the second inductor L2 and the impedance of the first capacitor C1 are all adjusted by a motor. The main control circuit 10 adjusts the impedance of the first inductor L1, the second inductor L2 and the first capacitor C1 according to the impedance of the plasma chamber so that the sum of the impedance of the impedance matching circuit 40 and the impedance of the nonlinear load in the plasma chamber is equal to the impedance of the RF power supply.

[0071] In this embodiment, the switch circuit 30 includes:

[0072] The first switch tube Q1 has an input end electrically connected to the first end of the impedance matching circuit 40 , an output end electrically connected to the electrode of the plasma chamber, and a controlled end electrically connected to the control end of the main control circuit 10 .

[0073] In this embodiment, the first switch tube Q1 is any one of a MOS tube, a triode or an IGBT tube.

[0074] refer to Figure 5In one embodiment of the present invention, the voltage detection circuit 20 includes:

[0075] A second resistor R2, a third resistor R3 and a photoelectric coupler U2, the first end of the second resistor R2 is electrically connected to the output end of the RF power supply, the second end of the second resistor R2 is electrically connected to the anode of the photodiode of the photoelectric coupler U2, the cathode of the photodiode of the photoelectric coupler U2 is grounded, the input end of the phototransistor of the photoelectric coupler U2 is connected to the first voltage, the output end of the phototransistor of the photoelectric coupler U2 is electrically connected to the signal receiving end of the main control circuit 10 and the first end of the third resistor R3 respectively, and the second end of the third resistor R3 is grounded.

[0076] In this embodiment, when the output voltage of the RF power supply increases, the conductivity of the phototransistor increases, thereby reducing the voltage received by the main control circuit 10. Conversely, when the output voltage of the RF power supply increases, the conductivity of the phototransistor decreases, thereby increasing the voltage received by the main control circuit 10. The main control circuit 10 determines the output voltage of the RF power supply based on the received voltage. The optocoupler U2 can achieve electrical isolation between the RF power supply and the main control circuit 10, helping to prevent the high-voltage side of the RF power supply or noise sources from interfering with the low-voltage side circuit (main control circuit 10), thereby improving the stability and reliability of the system.

[0077] In this embodiment, the voltage detection circuit 20 further includes:

[0078] The filter circuit has an input end electrically connected to the first end of the third resistor R3 , and an output end electrically connected to the signal receiving end of the main control circuit 10 .

[0079] The filter circuit includes a fourth resistor R4 and a second capacitor C2. The first end of the fourth resistor R4 is electrically connected to the first end of the second capacitor C2 and the input end of the phototransistor, respectively. The second end of the fourth resistor R4 is electrically connected to the signal receiving end of the main control circuit 10. The second end of the second capacitor C2 is grounded. The filter circuit is used to filter out noise and interference components in the first voltage, making the first voltage signal received by the main control circuit 10 purer and more stable, thereby helping to improve the accuracy and reliability of voltage detection.

[0080] The utility model also provides a plasma generating device, comprising a radio frequency power supply, a plasma chamber and the impedance matching device as described above.

[0081] It is worth noting that since the plasma generating device of the present invention is based on the above-mentioned impedance matcher, the embodiments of the plasma generating device of the present invention include all technical solutions of all embodiments of the above-mentioned impedance matcher, and the technical effects achieved are also exactly the same, which will not be repeated here.

[0082] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. An impedance matcher, applied to a plasma generating device, wherein the plasma generating device comprises a radio frequency power supply and a plasma chamber, wherein the radio frequency power supply outputs radio frequency energy to the plasma chamber via the impedance matcher, wherein: The impedance matching box includes: Main control circuit; a voltage detection circuit, wherein a detection end of the voltage detection circuit is electrically connected to the output end of the RF power supply, the voltage detection circuit is used to detect the output voltage of the RF power supply, and the output end of the voltage detection circuit is electrically connected to the signal receiving end of the main control circuit; A plurality of switch circuits, wherein the controlled ends of the plurality of switch circuits are electrically connected to the control end of the main control circuit; a plurality of impedance matching circuits, wherein the output end of the RF power supply is electrically connected to the first ends of the plurality of impedance matching circuits, the second ends of the plurality of impedance matching circuits are electrically connected to the input ends of the plurality of switch circuits in a one-to-one correspondence, the output ends of the plurality of switch circuits are electrically connected to the electrodes of the plasma chamber, and the controlled ends of the plurality of impedance matching circuits are electrically connected to the control end of the main control circuit; wherein the equivalent impedances of the plurality of impedance matching circuits are different; When the output voltage of the RF power supply reaches one of a plurality of preset voltage thresholds, the main control circuit controls the corresponding switch circuit to be turned on, and controls the other switch circuits to be turned off.

2. The impedance matching box according to claim 1, wherein: The main control circuit includes: Multiple comparator circuits, multiple reference source circuits and a main control module, the inverting ends of the multiple comparator circuits are connected to the multiple reference source circuits, the non-inverting ends of the multiple comparator circuits are electrically connected to the output end of the voltage detection circuit, and the output ends of the multiple comparator circuits are electrically connected to the signal receiving end of the main control module.

3. The impedance matching box according to claim 2, wherein: The reference source circuit comprises: A multiplexer and a resistor string, one end of the resistor string is connected to a first current, and the other end of the resistor string is grounded. The resistor string includes a plurality of first resistors electrically connected in sequence, each first resistor having a first end connected to the first current, and the first ends of the plurality of first resistors are electrically connected to the multiplexer. The output end of the multiplexer is electrically connected to the inverting end of the corresponding comparator circuit. The multiplexer includes a first signal receiving end, and the first signal receiving end is electrically connected to the control end of the main control module.

4. The impedance matching box according to claim 1, wherein: The switching circuit comprises: A first switching tube, wherein the input end of the first switching tube is electrically connected to the first end of the impedance matching circuit, the output end of the first switching tube is electrically connected to the electrode of the plasma chamber, and the controlled end of the first switching tube is electrically connected to the control end of the main control circuit.

5. The impedance matching box according to claim 1, wherein: The impedance matching circuit comprises: A first inductor, a second inductor and a first capacitor, wherein the first end of the first inductor is electrically connected to the output end of the RF power supply, the second end of the first inductor is electrically connected to the first end of the second inductor and the second end of the first capacitor respectively, the second end of the second inductor is electrically connected to the electrode of the plasma chamber, and the second end of the first capacitor is grounded; wherein the first inductor, the second inductor and the first capacitor are all impedance-adjustable devices, and the controlled end of the first inductor, the controlled end of the second inductor and the controlled end of the first capacitor are all electrically connected to the control end of the main control circuit.

6. The impedance matching box according to claim 1, wherein: The voltage detection circuit comprises: a second resistor, a third resistor and a photoelectric coupler, wherein the first end of the second resistor is electrically connected to the output end of the radio frequency power supply, the second end of the second resistor is electrically connected to the anode of the photodiode of the photoelectric coupler, the cathode of the photodiode of the photoelectric coupler is grounded, the input end of the phototransistor of the photoelectric coupler is connected to the first voltage, the output end of the phototransistor of the photocoupler is electrically connected to the signal receiving end of the main control circuit and the first end of the third resistor respectively, and the second end of the third resistor is grounded.

7. The impedance matching box according to claim 6, wherein: The voltage detection circuit further includes: A filter circuit, wherein an input end of the filter circuit is electrically connected to the first end of the third resistor, and an output end of the filter circuit is electrically connected to the signal receiving end of the main control circuit.

8. The impedance matching box according to claim 2, wherein: The comparator circuit comprises: A first comparator and amplifier circuit, wherein the inverting end of the first comparator is connected to the reference source circuit, the non-inverting end of the first comparator is electrically connected to the output end of the voltage detection circuit, the output end of the first comparator is electrically connected to the input end of the amplifier circuit, and the output end of the amplifier circuit is electrically connected to the signal receiving end of the main control module.

9. A plasma generating device, characterized in that: The invention comprises a radio frequency power supply, a plasma chamber and the impedance matching device according to any one of claims 1 to 8.

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