JP6397772B2 - Inverter device - Google Patents

Description

  The present invention relates to an inverter device that converts direct current power into high frequency alternating current power and outputs it to a load such as a plasma processing apparatus.

  Conventionally, when performing plasma processing such as etching in a semiconductor manufacturing process, a high-frequency power source for converting AC power of commercial frequency to high-frequency power is provided, and the output of the high-frequency power source is supplied to a plasma processing apparatus (load). Yes. The high-frequency power source includes a rectifier circuit that rectifies commercial AC power output from a commercial power source and converts it into DC power, and an inverter circuit that converts DC power output from the rectifier circuit into AC power. By switching between an energized state (hereinafter referred to as “on state”) and a non-energized state (hereinafter referred to as “off state”) of the switching element included in the inverter circuit, DC power is converted into AC power. Yes. In order to output high-frequency AC power from the inverter circuit, for example, there is a method of converting to high-frequency AC power by increasing the frequency (switching frequency) of the drive signal input to the switching element. However, generally, a switching loss occurs when switching the switching element between an on state and an off state. Therefore, when the switching frequency is increased, the number of switching between the ON state and the OFF state of the switching element (switching frequency) increases, and the switching loss increases. For example, if the switching frequency is operated at a triple of a certain frequency, the number of times of switching is also tripled. As a result, switching loss increases.

  Therefore, by providing an LC resonance circuit composed of an inductor and a capacitor, and setting the resonance frequency of this LC resonance circuit to three times the switching frequency, high-frequency AC power that is three times the switching frequency is output. A triple resonance inverter circuit is known that is capable of this. As a result, an increase in the number of switching operations can be prevented, and an increase in switching loss can be prevented. For example, Patent Literature 1 and Patent Literature 2 disclose a technology that uses this triple resonance inverter circuit for an induction heating cooker.

Japanese Patent No. 3907550 Japanese Patent No. 3884664

  FIG. 13 shows a circuit diagram when a conventional triple resonance inverter circuit is applied to a high frequency power supply (class D amplifier). This triple resonance inverter circuit converts a direct current output from a direct current power source DC into a high frequency alternating current and supplies it to a load. The triple resonance inverter circuit is composed of two switching elements TR0 and TR0 ′ and an LC resonance circuit in which an inductor L0 and a capacitor C0 are connected in series. The resonance frequency of the LC resonance circuit is 3 times the switching frequency. It is set to double. As a result, a high-frequency current having a frequency three times the switching frequency is output from the triple resonance inverter circuit, and a high-frequency alternating current can be supplied to the load while preventing an increase in the number of switching times.

  In the conventional triple resonance inverter circuit configured as described above, the drive signal (drive voltage) indicated by the solid line in FIG. 14A is input to the switching element TR0, and the drive indicated by the broken line in FIG. By inputting a signal (drive voltage) to the switching element TR0 ′, the on state and the off state are alternately switched. At this time, the voltage between the drain and the source of the switching element TR0 has a waveform shown by a solid line in FIG. 14B, and the current flowing through the drain of the switching element TR0 has a waveform shown by a broken line in FIG. Become. Similarly, the voltage between the drain and the source of the switching element TR0 ′ has a waveform indicated by the solid line in FIG. 14C, and the current flowing through the drain of the switching element TR0 ′ is indicated by the broken line in FIG. It becomes a waveform.

  Since these currents are output to the load, the alternating current (resonant current) supplied from the triple resonance inverter circuit to the load has a waveform as shown in FIG. 14 (d). A high-frequency alternating current having a frequency three times as high is output. FIG. 14D shows a current waveform of a frequency component that is three times the switching frequency. FIG. 15 is a diagram showing a result of frequency analysis of the resonance current shown in FIG. 14D by FFT (Fast Fourier Transform) analysis. Since the resonance current output from the conventional triple resonance inverter circuit is consumed and attenuated by the load resistance during the period when the switching element is in the ON state, the frequency component corresponding to the switching cycle is superimposed. . Accordingly, as shown in FIG. 14 (d), the waveform of the resonance current is a distorted waveform having a period variation corresponding to the switching period. Also in the analysis result shown in FIG. 15, it can be seen that not only the desired triple frequency component but also an unnecessary switching frequency component is superimposed. When such a conventional triple resonance inverter circuit is used as a high frequency power source, unnecessary radiation is superimposed on the high frequency alternating current supplied to the load, which adversely affects the semiconductor manufacturing process.

  Therefore, the present invention has been created in view of the above problems, and prevents an increase in switching loss that occurs when the switching element is switched between an on state and an off state. It is an object of the present invention to provide an inverter device that is capable of outputting a stable high-frequency alternating current while suppressing fluctuations in the period of current supplied to.

  An inverter device provided by the first aspect of the present invention is an inverter device that converts a direct current output from a direct current power source into an alternating current and outputs the alternating current, and is connected to a positive electrode side of the direct current power source. A switching circuit in which N switching arms connected in series to a DC power supply are connected in series with one switching element and a second switching element connected to the negative electrode side of the DC power supply. A drive signal for switching between the energized state and the de-energized state of the first switching element and the second switching element is shifted in phase by 2π / N [rad] for each arm, and the first switching element and the At the connection point between the control means for inputting to the second switching element and the first switching element and the second switching element of each arm. With a respectively connected resonant circuit, and outputs said N AC current at a resonant current synthesis to the output from the resonance circuit.

  An inverter device provided by the second aspect of the present invention is a switching circuit in which a first switching element connected to a positive electrode side of a DC power supply and a second switching element connected to a negative electrode side of the DC power supply are connected in series. And a control means for inputting a drive signal for switching between an energized state and a non-energized state of the first switching element and the second switching element to the first switching element and the second switching element, and the switching circuit N resonance inverter circuits each including a resonance circuit connected to a connection point between the first switching element and the second switching element are connected at the output terminal of the resonance inverter circuit, , A drive signal whose phase is shifted by 2π / N [rad] is input to each of the N switching circuits, and the N The resonant current is an alternating current output from the resonance circuit of the resonance inverter circuit is synthesized and output.

  Preferably, in the inverter device provided by the first aspect and the second aspect of the present invention, the N is an odd number of 3 or more.

  When N is 3, the resonance frequency of the resonance circuit is set to 2.5 to 3.5 times the frequency of the drive signal.

  In the inverter device provided by the first aspect and the second aspect of the present invention, an inductor having a predetermined inductance is provided instead of the first switching element, and the control means includes the second switching element. It is also possible to input a drive signal for switching between the energized state and the non-energized state.

  In the inverter device provided by the first aspect and the second aspect of the present invention, the resonance circuit is preferably an LC series resonance circuit in which an inductor and a capacitor are connected in series.

  In the inverter device provided by the first aspect and the second aspect of the present invention, the resonance circuit may be capable of changing an inductance of the inductor or a capacitance of the capacitor.

  An inverter device provided by the third aspect of the present invention is an inverter device that converts a direct current output from a direct current power source into an alternating current and outputs the alternating current to a load, and is connected to the positive electrode side of the direct current power source. A switching circuit in which N arms connected in series with the DC power supply are connected in series to the first switching element and a second switching element connected to the negative electrode side of the DC power supply. Drive signals for switching between the energized state and the de-energized state of the first switching element and the second switching element that are shifted in phase by 2π / N [rad] for each arm, and the first switching element And a control means for inputting to the second switching element, and a connection between the first switching element and the second switching element of each arm. And an LC circuit including an inductor connected in series to the load and connected in parallel to the load, and a capacitor connected in parallel to the load, and an output current output from the N LC circuits Are output to the load.

  According to the present invention, since the drive signals input to the switching elements of the N connected arms are shifted in phase by 2π / N [rad], the period variation of the resonance current output from each resonance circuit is reduced. The phase is also shifted by 2π / N [rad]. Therefore, the output current obtained by synthesizing the resonance currents output from the respective resonance circuits is one in which periodic fluctuations are suppressed by compensating each other for attenuation of the resonance currents. Thereby, an increase in switching loss can be prevented and a stable high-frequency alternating current can be output from the inverter device.

It is a figure which shows the structural example of the plasma processing system which concerns on 1st Embodiment. In the plasma processing system which concerns on 1st Embodiment, it is a figure which shows various waveforms when the resonance frequency of a resonance part is set lower than the frequency of 3 times the switching frequency. It is a figure which shows the analysis result when the FFT analysis of the load current which flows into the plasma processing apparatus which concerns on 1st Embodiment is carried out. In the plasma processing system which concerns on 1st Embodiment, it is a figure which shows various waveforms when the resonance frequency of a resonance part is set higher than the frequency of 3 times the switching frequency. In the plasma processing system which concerns on 1st Embodiment, it is a figure which shows the current waveform of load current when changing the resonant frequency of a resonance part. In the plasma processing system which concerns on 1st Embodiment, it is a figure which shows the analysis result of the FFT analysis of load current when changing the resonant frequency of a resonance part. It is a figure which shows the structural example of the plasma processing system which concerns on 2nd Embodiment. It is a figure which shows the various waveforms in the plasma processing system which concerns on 2nd Embodiment. It is a figure which shows the structural example of the plasma processing system which concerns on 3rd Embodiment. It is a figure which shows the structural example of the plasma processing system which concerns on 4th Embodiment. It is a figure which shows the structural example of the plasma processing system which concerns on 5th Embodiment. It is a figure which shows the electric current waveform and FFT analysis result in the plasma processing system which concerns on 5th Embodiment. It is a figure which shows the structural example at the time of applying the conventional triple resonance inverter circuit to a high frequency power supply. It is a figure which shows the various waveforms in the conventional high frequency power supply. It is a figure which shows the analysis result when the FFT analysis of the resonance current output from the conventional high frequency power supply is carried out.

  As an embodiment of the inverter device according to the present invention, a case where the present invention is applied to a plasma processing system will be described as an example. FIG. 1 is a diagram illustrating a configuration of a plasma processing system 1 according to the first embodiment. As shown in the figure, the plasma processing system 1 according to the first embodiment includes a DC power source 10, an inverter device 20, and a plasma processing device 30.

  The plasma processing system 1 is a system that converts DC power output from the DC power supply 10 into high-frequency AC power by an inverter device 20 and supplies the converted high-frequency AC power to the plasma processing device 30. Here, the DC power supply 10 and the inverter device 20 have a function as a high-frequency power supply. In the plasma processing apparatus 30, for example, processing such as plasma etching is performed on a workpiece such as a semiconductor wafer or a liquid crystal substrate using the supplied high-frequency AC power. Preferably, in order to suppress the reflected wave of the high-frequency AC power output from the inverter device 20, an impedance matching device that adjusts the impedance of the plasma processing device 30 viewed from the output end of the inverter device 20 is connected to the inverter device 20 and the plasma. It is good to prepare between the processing apparatus 30.

  The DC power supply 10 outputs DC power (DC current), and includes, for example, a rectifier circuit that rectifies input AC current and a smoothing capacitor that smoothes the input AC current. The DC power supply 10 performs full-wave rectification on a commercial AC current input from a commercial power supply (not shown) using a rectifier circuit, smoothes it with a smoothing capacitor, converts the DC current into a DC current, and outputs the DC current. Note that the DC power supply 10 is not limited to one that converts an alternating current into a direct current and outputs it, and may be one that outputs a direct current such as a fuel cell, storage battery, or solar cell.

  The inverter device 20 converts a direct current input from the direct current power source 10 into a high frequency alternating current and outputs the high frequency alternating current. The inverter device 20 is a triple resonance inverter capable of outputting a high-frequency alternating current having a frequency three times the switching frequency by setting the resonance frequency of the built-in LC resonance circuit to approximately three times the switching frequency. Includes three circuits. Therefore, in order to set the frequency of the high-frequency alternating current output from the inverter device 20 to a desired frequency, the switching frequency is set to 1/3 times the frequency of the desired high-frequency alternating current, and the resonance frequency is switched. Set to approximately three times the frequency. These details are described below. As shown in FIG. 1, the inverter device 20 includes six switching elements TR1 to TR6, three inductors L1 to L3, three capacitors C1 to C3, a voltage / current detection unit 201, and a control unit 202. It consists of In this embodiment, the switching elements TR1 to TR6 will be described using an example of using a MOSFET, but a semiconductor switching element other than the MOSFET (for example, a bipolar transistor or an IGBT) may be used.

  In the switching elements TR1 and TR2, the source terminal of the switching element TR1 and the drain terminal of the switching element TR2 are connected in series. The drain terminal of the switching element TR1 is connected to the positive electrode side of the DC power supply 10, and the source terminal of the switching element TR2 is connected to the negative electrode side of the DC power supply 10 to form a bridge structure. Similarly, switching elements TR3 and TR4 are connected in series to form a bridge structure, and switching elements TR5 and TR6 are connected in series to form a bridge structure. Here, the bridge structure formed by the switching elements TR1 and TR2 is the first arm, the bridge structure formed by the switching elements TR3 and TR4 is the second arm, and the bridge structure formed by the switching elements TR5 and TR6. Is the third arm. The first arm, the second arm, and the third arm are connected to the DC power supply 10 in parallel. The output line is connected to the connection point between the switching elements TR1 and TR2 of the first arm, and the connection point between the switching elements TR3 and TR4 of the second arm and the switching elements TR5 and TR6 of the third arm. The output lines are also connected to the connection points. The circuit constituted by the first arm, the second arm, and the third arm corresponds to the “switching circuit” in claim 1.

  A driving signal Q1 is input from the control unit 202 to the gate terminal of the switching element TR1, and the switching element TR1 is switched between an on state and an off state based on the driving signal Q1. Similarly, drive signals Q2 to Q6 are input from the control unit 202 to the gate terminals of the switching elements TR2 to TR6, respectively. Based on the drive signals Q2 to Q6, the ON state and the OFF state of the switching elements TR2 to TR6 are changed. Can be switched. Since both ends of each arm are connected to the positive electrode side and the negative electrode side of the DC power supply 10, respectively, the positive electrode side switching element TR1 (TR3, TR5) is in the ON state and the negative electrode side switching element TR2 (TR4, TR6). When is in the OFF state, the potential of the output line of each arm is the potential on the positive side of the DC power supply 10. On the other hand, when the switching element TR1 (TR3, TR5) on the positive electrode side is off and the switching element TR2 (TR4, TR6) on the negative electrode side is on, the potential of the output line of each arm is It becomes a potential.

  The inductor L1 and the capacitor C1 are connected in series to form an LC series resonance circuit. Similarly, the inductor L2 and the capacitor C2 are connected in series, and the inductor L3 and the capacitor C3 are connected in series, and each constitutes an LC series resonance circuit. The LC series resonance circuit composed of the inductor L1 and the capacitor C1 is defined as a resonance part LC1, and similarly, the LC series resonance circuit composed of the inductor L2 and the capacitor C2 is defined as a resonance part LC2, an inductor L3, and a capacitor C3. The configured LC series resonance circuit is defined as a resonance unit LC3. The resonance frequencies of the resonance units LC1 to LC3 are set to a frequency that is approximately three times the frequency (switching frequency) of the drive signals Q1 to Q6 that are input to the switching elements TR1 to TR6 by the control unit 202 described later. Note that the resonance frequencies of the resonance units LC1 to LC3 are all set to the same frequency. Preferably, when performing soft switching (voltage zero switching or current zero switching) for further preventing switching loss of the switching elements TR1 to TR6, the frequency may be set slightly lower than three times the switching frequency. Each of the resonance portions LC1 to LC3 corresponds to a “resonance circuit” in claim 1.

  One end of the resonance part LC1 is connected to the output line connected to the first arm, one end of the resonance part LC2 is connected to the output line connected to the second arm, and one end of the resonance part LC3 is connected to the third arm. Connected to the output line connected to. The other ends of the resonance parts LC1 to LC3 are connected at one point (connection point A), and currents flowing through the resonance parts LC1 to LC3 (hereinafter referred to as “resonance current”) ir1, ir2, and ir3 are connected to the connection point A. Is synthesized. Then, the resonance currents ir1 to ir3 synthesized at the connection point A are output (supplied) to the plasma processing apparatus 30. Hereinafter, the synthesized current IRc1 is expressed as “load current”.

  The voltage / current detector 201 includes a voltmeter and an ammeter, detects a voltage applied from the inverter device 20 to the plasma processing device 30 with the voltmeter, and outputs the voltage from the inverter device 20 to the plasma processing device 30 with the ammeter. Current is detected. The voltage / current detection unit 201 outputs the detected voltage value and current value to the control unit 202.

  The control unit 202 includes a microcomputer having a ROM, a RAM, a CPU, an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), and the like. The control unit 202 generates drive signals Q1 to Q6 adjusted so that the voltage value and the current value input from the voltage / current detection unit 201 become the set voltage or the set current. Then, the control unit 202 inputs the generated drive signals Q1 to Q6 to the switching elements TR1 to TR6, respectively, and switches the switching elements TR1 to TR6 between the on state and the off state. Thereby, the direct current input from the direct current power supply 10 is converted into an alternating current. In the present embodiment, since the switching elements TR1 to TR6 are MOSFETs, an on state and an off state are switched by applying a voltage to the gate terminal. It is turned on when a voltage is applied to the gate terminals of the switching elements TR1 to TR6, and is turned off when no voltage is applied. Therefore, the control unit 202 generates a pulse wave voltage signal as the drive signals Q1 to Q6. The duty ratios of drive signals Q1, Q3, Q5 (Q2, Q4, Q6) are the same, and the amplitudes of drive signals Q1-Q6 are all the same. The control unit 202 adjusts the voltage and current output from the inverter device 20 by changing the duty ratio and amplitude of the pulse wave. In the above, the control unit 202 will be described as an example in which the drive signals Q1 to Q6 are adjusted so that the voltage value and the current value input from the voltage / current detection unit 201 become the set voltage or the set current. Not limited to this, the power value may be obtained from the voltage value and current value input from the voltage / current detector 201, and the drive signals Q1 to Q6 may be adjusted so that the power value becomes the set power. In addition, when adjusting so that an electric power value may become set power, you may use the electric power detection part which detects electric power instead of the voltage current detection part 201. FIG.

  The control unit 202 generates drive signals Q1 and Q2 so that when one of the switching elements TR1 and TR2 constituting the first arm is in an on state, the other is in an off state. Similarly, the control unit 202 generates the drive signals Q3 and Q4 so that when one of the switching elements TR3 and TR4 configuring the second arm is turned on, the other is turned off, thereby configuring the third arm. The drive signals Q5 and Q6 are generated so that when one of the switching elements TR5 and TR6 is turned on, the other is turned off. That is, the two drive signals (Q1 and Q2, Q3 and Q4, Q5 and Q6) input to one arm are inverted. In addition, the control unit 202 performs a multi-phase operation in which the drive signal input to each arm is shifted by 2π / 3 [rad] (= 120 °). Specifically, when the phase of the drive signals Q1 and Q2 input to the first arm is a reference (0 °), the control unit 202 sets the phase of the drive signals Q3 and Q4 input to the second arm to 120 ° and the first phase. The drive signals Q5 and Q6 input to the three arms are generated by delaying the phase by 240 ° and input to each arm.

  The frequencies (switching frequencies) of the drive signals Q1 to Q6 generated by the control unit 202 are set based on the frequency of a desired high-frequency alternating current supplied to the plasma processing apparatus 30. Specifically, the switching frequency is set to 1/3 times the frequency of the desired high-frequency alternating current supplied to the plasma processing apparatus 30.

  Preferably, the control unit 202 switches the switching elements TR1 to TR6 when the voltage is 0 (zero) or the current is 0 (zero) based on the high frequency voltage or the detected value of the high frequency current input from the voltage / current detection unit 201. Soft switching (voltage zero switching or current zero switching) is performed to switch between an on state and an off state.

  The plasma processing apparatus 30 includes a processing unit (not shown), and is a device for processing (etching or the like) a workpiece such as a wafer or a liquid crystal substrate carried into the processing unit. In order to process a workpiece, the plasma processing apparatus 30 introduces a plasma discharge gas into a processing portion and uses a high frequency alternating current (high frequency alternating current power) output from the inverter device 20 to generate a plasma discharge. The working gas is changed from a non-plasma state to a plasma state. Then, the workpiece is processed using plasma.

  In the plasma processing system 1 according to the first embodiment configured as described above, the resonance current flowing through each of the resonance portions LC1 to LC3 and the high-frequency alternating current output from the inverter device 20 (load current flowing through the plasma processing device 30). This will be described in detail.

  FIG. 2 shows a case where the switching frequency of the drive signals Q1 to Q6 output from the control unit 202 to the switching elements TR1 to TR6 is set to 13.56 MHz and the resonance frequency is set to 38.9 MHz, that is, a frequency three times the switching frequency. Various waveforms are shown in the case where the resonance frequency is set to be lower (about 2.87 times the switching frequency).

  FIG. 2A shows voltage waveforms of the drive signal Q1 input to the switching element TR1 and the drive signal Q2 input to the switching element TR2. FIG. 2B shows voltage waveforms of the drive signal Q3 input to the switching element TR3 and the drive signal Q4 input to the switching element TR4, and FIG. 2C is input to the switching element TR5. The voltage waveforms of the drive signal Q5 and the drive signal Q6 input to the switching element TR6 are shown. As shown in FIGS. 2A to 2C, the control unit 202 generates the drive signals Q1, Q3, and Q5 while shifting them by 120 ° and inputs them to the switching elements TR1, TR3, and TR5, respectively. Similarly, the drive signals Q2, Q4, and Q6 are generated while being shifted by 120 ° and input to the switching elements TR2, TR4, and TR6, respectively.

  When these drive signals Q1 to Q6 are input to the switching elements TR1 to TR6, respectively, the DC current output from the DC power supply 10 is converted into an AC current by the operation of each switching element TR1 to TR6. At this time, resonance currents ir1 to ir3 shown in FIG. 2 (d) flow to the resonance portions LC1 to LC3 by the resonance portions LC1 to LC3 connected to the arms. In FIG. 2D, the resonance current ir1 output from the first arm is indicated by a solid line, the resonance current ir2 output from the second arm is indicated by a broken line, and the resonance current ir3 output from the third arm is indicated by a one-dot chain line. Yes. At this time, the resonance currents ir1 to ir3 output from each arm have a waveform having a period variation corresponding to the switching period, as in the conventional triple resonance inverter circuit.

  The resonance currents ir1 to ir3 flowing through the resonance units LC1 to LC3 are combined at the connection point A and output to the plasma processing apparatus 30. At this time, the load current (high-frequency alternating current) IRc1 flowing in the plasma processing apparatus 30 has a waveform shown in FIG. As shown in FIG. 2 (e), the load current IRc1 has a stable waveform with suppressed period fluctuations observed in the resonance currents ir1 to ir3. This is because the resonance currents ir1 to ir3 shown in FIG. 2D are combined to compensate for the attenuation of the resonance currents ir1 to ir3. Therefore, the load current IRc1 is suppressed in periodic fluctuation, becomes a stable high-frequency alternating current, and a stable high-frequency alternating current can be supplied from the inverter device 20 to the plasma processing apparatus 30. Furthermore, as shown in FIG. 2E, the load current IRc1 has a frequency that is three times the switching frequency. Therefore, the inverter device 20 can output a high-frequency alternating current having a frequency that is three times the switching frequency, and can reduce the switching loss.

  FIG. 3 shows the results when FFT analysis is performed on the load current IRc1 supplied to the plasma processing apparatus 30. The resonance current supplied to the load from the conventional triple resonance inverter circuit shown in FIG. 15 has not only a frequency component of three times the desired switching frequency but also an unnecessary switching frequency component superimposed thereon. In the load current IRc1 shown in FIG. 2, only a frequency component that is three times the desired switching frequency is obtained, and unnecessary switching frequency components are attenuated.

  Subsequently, FIG. 4 shows a case where the switching frequency of the drive signals Q1 to Q6 output from the control unit 202 to the switching elements TR1 to TR6 is set to 13.56 MHz and the resonance frequency is set to 43.3 MHz, that is, 3 of the switching frequency. Various waveforms in the case where the resonance frequency is set higher than the double frequency (about 3.19 times the switching frequency) are shown.

  FIG. 4A shows voltage waveforms of the drive signal Q1 input to the switching element TR1 and the drive signal Q2 input to the switching element TR2. FIG. 4B shows voltage waveforms of the drive signal Q3 input to the switching element TR3 and the drive signal Q4 input to the switching element TR4, and FIG. 4C is input to the switching element TR5. The voltage waveforms of the drive signal Q5 and the drive signal Q6 input to the switching element TR6 are shown. As shown in FIGS. 4A to 4C, the control unit 202 generates the drive signals Q1, Q3, and Q5 while shifting them by 120 ° and inputs them to the switching elements TR1, TR3, and TR5, respectively. Similarly, the drive signals Q2, Q4, and Q6 are generated while being shifted by 120 ° and input to the switching elements TR2, TR4, and TR6, respectively.

  When these drive signals Q1 to Q6 are input to the switching elements TR1 to TR6, respectively, the DC current output from the DC power supply 10 is converted into an AC current by the operation of each switching element TR1 to TR6. At this time, resonance currents ir1 to ir3 shown in FIG. 4 (d) flow to the resonance portions LC1 to LC3 by the resonance portions LC1 to LC3 connected to the arms. In FIG. 4D, the resonance current ir1 output from the first arm is indicated by a solid line, the resonance current ir2 output from the second arm is indicated by a broken line, and the resonance current ir3 output from the third arm is indicated by a one-dot chain line. Yes. At this time, the resonance currents ir1 to ir3 output from each arm have a larger attenuation during the ON period of the switching element than the resonance current shown in FIG.

  The resonance currents ir1 to ir3 flowing through the resonance units LC1 to LC3 are combined at the connection point A and output to the plasma processing apparatus 30. At this time, the load current (high-frequency alternating current) IRc1 flowing in the plasma processing apparatus 30 has a waveform shown in FIG. As shown in FIG. 4 (e), the load current IRc1 has a stable waveform with the periodic fluctuations observed in the resonance currents ir1 to ir3 being suppressed. This is because the resonance currents ir1 to ir3 shown in FIG. 4D are combined to compensate for the attenuation of the resonance currents ir1 to ir3. Therefore, the load current IRc1 is suppressed in periodic fluctuation, becomes a stable high-frequency alternating current, and a stable high-frequency alternating current can be supplied from the inverter device 20 to the plasma processing apparatus 30. Further, as shown in FIG. 4E, the load current IRc1 has a frequency that is three times the switching frequency. Therefore, the inverter device 20 can output a high-frequency alternating current having a frequency three times the switching frequency, and can reduce the switching loss. Further, the output current can be stabilized regardless of whether the resonance frequency set in each of the resonance units LC1 to LC3 is higher or lower than three times the switching period. Note that the resonance frequency is higher (FIG. 4), the attenuation of each resonance current is larger, and the synthesized current is smaller (see the amplitudes in FIGS. 2 (e) and 4 (e)). desirable.

  As described above, according to the plasma processing system 1 according to the first embodiment of the present invention, three arms in which two switching elements are connected in series are connected in parallel, and an inductor and an output line are connected to each arm. An LC series resonance circuit (resonance units LC1 to LC3) in which capacitors are connected in series is connected. In the inverter device 20 configured as described above, the resonance frequency of the LC series resonance circuit is set to a frequency that is approximately three times the switching frequency, and the control unit 202 is 2π / 3 [rad] (= 120 °). Drive signals that are shifted one by one are generated and input to each arm. Then, the resonance currents ir1 to ir3 output from the respective LC series resonance circuits are synthesized and supplied to the plasma processing apparatus 30. Thereby, the phase of the periodic fluctuation of the resonance current output from each LC series resonance circuit is also shifted by 2π / 3 [rad], and an output current (load current IRc1) obtained by synthesizing the resonance current output from each LC series resonance circuit. In other words, each resonance current compensates for each other to suppress the period fluctuation. Therefore, the load current IRc1 flowing through the plasma processing apparatus 30 becomes a stable high-frequency alternating current, and the inverter device 20 can supply the stable high-frequency alternating current to the plasma processing apparatus 30. Furthermore, since the three resonance currents are combined, a high-output high-frequency alternating current can be supplied.

  In the first embodiment, the example in which the resonance frequency of the resonance units LC1 to LC3 is set to a frequency that is approximately three times the switching frequency has been described. However, the present invention is not limited to this. A stable high-frequency alternating current can be supplied. FIG. 5 shows a current waveform of the load current IRc1 when the resonance frequencies of the resonance units LC1 to LC3 are changed. 5A to 5E, the resonance frequencies of the resonance parts LC1 to LC3 are set to 1.25 times, 2.1 times, 2.5 times, 3.5 times, and 5.3 times the switching frequency, respectively. Load current IRc1 is shown. As can be seen from FIG. 5, it can be seen that a stable high-frequency alternating current is supplied to the plasma load even when the resonance frequency is changed. FIG. 6 shows an analysis result when the FFT analysis of the load current IRc1 shown in FIG. 5 is performed, and the desired frequency component is output highest even when the resonance frequency is changed.

  From the above, in the plasma processing system 1 according to the first embodiment, the resonance frequency of the resonance units LC1 to LC3 is not limited to approximately three times the switching frequency, and the inverter device 20 performs plasma processing on stable high-frequency alternating current. The device 30 can be supplied. However, as shown in FIG. 6, as the resonance frequency is separated from three times the switching frequency, unnecessary frequency components are superimposed and unnecessary radiation increases, so that the resonance frequencies of the resonance units LC1 to LC3 are approximately three times ( It is desirable to set it to about 2.5 to 3.5 times.

  Further, in the first embodiment, the case where three arms configured by the switching element TR1 and the switching element TR2 are connected in parallel to the DC power supply 10 has been described as an example, but the present invention is not limited to this, and the switching element TR1, Similar effects can be obtained by using inductors instead of TR3 and TR5. This case will be described below as a second embodiment.

  FIG. 7 is a diagram showing the configuration of the plasma processing system 2 according to the second embodiment of the present invention. In addition, about the structure which is the same as that of 1st Embodiment, or similar, the same code number is attached | subjected and the description is abbreviate | omitted. As shown in the figure, the plasma processing system 2 according to the second embodiment includes a DC power supply 10, an inverter device 21, and a plasma processing device 30. Compared with the plasma processing system 1 according to the first embodiment, the configuration of the inverter device 21 is different.

  The inverter device 21 converts a direct current input from the direct current power source 10 into a high frequency alternating current and outputs it. As shown in FIG. 7, the inverter device 21 includes three switching elements TR2, TR4, TR6, six inductors L1 to L3, Lr11 to Lr13, three capacitors C1 to C3, a voltage / current detection unit 201, and The control unit 212 is included. The inverter device 21 is different from the inverter device 20 of the first embodiment in that the switching elements TR1, TR3, TR5 are replaced with inductors Lr11, Lr12, Lr13. That is, the inductor Lr11 and the switching element TR2 are connected in series to form a first arm. Similarly, inductor Lr12 and switching element TR4 are connected in series to form a second arm, and inductor Lr13 and switching element TR6 are connected in series to form a third arm. The first arm, the second arm, and the third arm are connected in parallel to the series power supply 10.

  The resonance frequency of the resonance part LC1 (LC2, LC3) composed of the inductor L1 (L2, L3) and the capacitor C1 (C2, C3) is set to a frequency approximately three times the switching frequency of the drive signal Q12 (Q14, Q16). Keep it. Preferably, when soft switching (voltage zero switching or current zero switching) for preventing switching loss of the switching elements TR2, TR4, TR6 is performed, the frequency is set slightly lower than three times the switching frequency. Good. As in the first embodiment, the resonance frequency of the resonance units LC1 to LC3 is not limited to approximately three times the switching frequency, but is preferably set to approximately three times the frequency.

  The output ends of the resonance parts LC1 to LC3 are connected at one point (connection point B), and the resonance currents ir11, ir12 and ir13 flowing through the resonance parts LC1 to LC3 are combined at the connection point B. Then, the current synthesized at the connection point B (load current IRc2) is output (supplied) to the plasma processing apparatus 30.

  The control unit 212 has the same configuration as the control unit 202 of the first embodiment, and generates drive signals Q12, Q14, and Q16 that are input to the switching elements TR2, TR4, and TR6. At this time, the control unit 212 adjusts the drive signals Q12, Q14, and Q16 so that the voltage value and the current value input from the voltage / current detection unit 201 become the set voltage and the set current.

  The control unit 212 also performs a multiphase operation in which drive signals input to the switching elements TR2, TR4, and TR6 are shifted by 2π / 3 [rad] (= 120 °). Specifically, when the phase of the drive signal Q12 input to the switching element TR2 is a reference (0 °), the control unit 212 inputs the phase of the drive signal Q14 input to the switching element TR4 to 120 ° and the switching element TR6. The phase of the drive signal Q16 to be delayed is delayed by 240 ° and input to the switching elements TR2, TR4, TR6. Preferably, similarly to the control unit 202, the control unit 212 performs soft switching.

  Thus, in the plasma processing system 2 according to the second embodiment configured as described above, the resonance current flowing through each of the resonance units LC1 to LC3 and the high-frequency alternating current output from the inverter device 21 (load current flowing through the plasma processing device 30). Will be described in detail.

  FIG. 8 is a diagram showing various waveforms (drive signals and currents) in the plasma processing system 2 according to the second embodiment. FIG. 8A shows voltage waveforms of the drive signals Q12, Q14, and Q16 input to the switching elements TR2, TR4, and TR6. As shown in the figure, the control unit 212 generates the drive signals Q12, Q14, and Q16 while shifting them by 120 °, and inputs them to the switching elements TR2, TR4, and TR6, respectively. When the drive signals Q12, Q14, and Q16 shown in FIG. 8A are input to the switching elements TR2, TR4, and TR6, respectively, the direct current output from the DC power supply 10 is applied to the switching elements TR2, TR4, and TR6. It is converted into an alternating current by operation. At this time, the resonance currents ir11 to ir13 shown in FIG. 8B flow through the resonance portions LC1 to LC3 by the resonance portions LC1 to LC3. As shown in FIG. 8B, the resonance currents ir11 to ir13 flowing through the resonance units LC1 to LC3 have a waveform having a period variation corresponding to the switching period, as in the first embodiment.

  The resonance currents ir11 to ir13 flowing through the resonance units LC1 to LC3 are combined at the connection point B and output to the plasma processing apparatus 30. At this time, the load current (high-frequency alternating current) IRc2 flowing in the plasma processing apparatus 30 has a waveform shown in FIG. As shown in FIG. 8C, the load current IRc2 has a stable waveform in which the periodic fluctuations observed in the resonance currents ir11 to ir13 are suppressed. This is because the resonance currents ir11 to ir13 shown in FIG. 8B are combined to compensate for the attenuation of the resonance currents ir11 to ir13. Thus, the load current IRc2 is suppressed in periodic fluctuations, becomes a stable high-frequency alternating current, and can be supplied from the inverter device 21 to the plasma processing apparatus 30. Furthermore, as shown in FIG. 8C, the load current IRc2 has a frequency that is three times the switching frequency. Therefore, the inverter device 21 can output a high-frequency alternating current having a frequency three times the switching frequency, and can reduce switching loss.

  As described above, according to the plasma processing system 2 according to the second embodiment of the present invention, in the inverter device 21 that converts the DC current input from the DC power supply 10 into the high-frequency AC current, Even if the inductors Lr11, Lr12, and Lr13 are used instead of the switching elements TR1, TR3, and TR5, the output current (load current IRc2) obtained by synthesizing the resonance currents ir11 to ir13 flowing through the resonance units LC1 to LC3 is the resonance current. Compensate for each other to suppress periodic fluctuations. Therefore, the load current IRc2 flowing through the plasma processing apparatus 30 becomes a stable high-frequency alternating current, and the inverter device 21 can supply the stable high-frequency alternating current to the plasma processing apparatus 30.

  In the first embodiment and the second embodiment, the case where high frequency alternating current (load current) is supplied to the plasma processing apparatus 30 by synthesizing three resonance currents has been described as an example. If a high frequency alternating current obtained by synthesizing a resonance current of N is an odd number of 3 or more is supplied to the plasma processing apparatus 30, a stable high frequency alternating current can be output as in the first embodiment. . The inverter device in this case has a circuit configuration including N arms and N resonating units. Further, the control unit inputs a drive signal shifted by 2π / N [rad] to each arm. For example, the case where N is 5 will be described below as a third embodiment. The first embodiment is an embodiment where N is 3.

  FIG. 9 is a diagram showing the configuration of the plasma processing system 3 according to the third embodiment of the present invention. In addition, about the structure which is the same as that of 1st Embodiment and 2nd Embodiment, or similar, the same code number is attached | subjected and the description is abbreviate | omitted. As shown in the figure, the plasma processing system 3 according to the third embodiment includes a DC power source 10, an inverter device 22, and a plasma processing device 30. Compared with the plasma processing system 1 according to the first embodiment, the configuration of the inverter device 22 is different.

  The inverter device 22 converts a direct current input from the direct current power source 10 into a high frequency alternating current and outputs it. As shown in FIG. 9, the inverter device 22 includes ten switching elements TR1 to TR10, five inductors L1 to L5, five capacitors C1 to C5, a voltage / current detection unit 201, and a control unit 222. It consists of As shown in the figure, in the inverter device 20 of the first embodiment, three arms having two switching elements are connected in parallel to the DC power supply 10 and an inductor and a capacitor are connected to the output line connected to each arm, respectively. In the inverter device 22 of the third embodiment, two more arms are added, and a total of five arms are connected in parallel to the DC power supply 10. ing. Thereby, a resonance part LC4 composed of an inductor L4 and a capacitor C4 and a resonance part LC5 composed of an inductor L5 and a capacitor C5 are added, and a total of five resonance parts LC1 to LC5 are included.

  The driving signals Q21 to Q30 are input from the control unit 222 to the switching elements TR1 to TR10, and the on and off states of the switching elements TR1 to TR10 are switched. At this time, the resonance frequency of each of the resonance units LC1 to LC5 is set to a frequency that is substantially five times the frequency (switching frequency) of the drive signals Q21 to Q30, which is also different from the first embodiment. As in the first embodiment, the resonance frequencies of the resonance units LC1 to LC5 may be any number, but it is desirable to set a frequency that is approximately five times. Then, the load current IRc3 obtained by synthesizing the resonance currents flowing through the resonance portions LC1 to LC5 at the connection point C is supplied to the plasma processing apparatus 30.

  The control unit 222 has the same configuration as the control unit 202 and the control unit 212, and generates drive signals Q21 to Q30 that are input to the switching elements TR1 to TR10. The control unit 222 differs from the control unit 202 and the control unit 212 in that a drive signal shifted by 2π / 5 [rad] (= 72 °) is input to each arm.

  In the plasma processing system 3 according to the third embodiment configured as described above, the resonance currents ir21 to ir25 output from the respective arms have a waveform having a period variation corresponding to the switching period, as in the first embodiment. However, by synthesizing the resonance currents ir21 to ir25 output from each arm at the connection point C, the load current IRc3 flowing through the plasma processing apparatus 30 is suppressed from periodic fluctuations and becomes a stable high-frequency alternating current.

  As described above, also in the plasma processing system 3 according to the third embodiment of the present invention, the resonance currents ir21 to ir25 output from the arms and output from the LC series resonance circuits (resonance units LC1 to LC5). Was synthesized and supplied to the plasma processing apparatus 30. Thereby, the phase of the periodic fluctuation of the resonance current output from each LC series resonance circuit is also shifted by 2π / 5 [rad], and the output current (load current IRc3) obtained by synthesizing the resonance current output from each LC series resonance circuit. In other words, each resonance current compensates for each other to suppress the period fluctuation. Therefore, the load current IRc3 flowing through the plasma processing apparatus 30 becomes a stable high-frequency alternating current, and the inverter device 22 can supply the stable high-frequency alternating current to the plasma processing apparatus 30. As a result, even in a configuration in which N arms are connected in parallel to the DC power source 10 and an LC series resonance circuit is connected to the output line of each arm, a stable high-frequency AC current is similarly applied to the plasma processing apparatus 30. Can be supplied.

  In the third embodiment, as in the second embodiment, the switching element connected to the positive electrode side of the DC power supply 10 can be replaced with an inductor. At this time, the control unit 222 supplies a stable high-frequency alternating current to the plasma processing apparatus 30 by inputting a drive signal shifted by 2π / N [rad] to the switching element connected to the negative electrode side of the DC power supply 10. can do.

  In the first to third embodiments, the case where the DC current output from one DC power supply 10 is converted into a high-frequency AC current and supplied to the plasma processing apparatus 30 has been described as an example, but the present invention is not limited thereto. Absent. For example, N high-frequency power sources each including a DC power source, an arm in which two switching elements are connected in series, and an LC series resonance circuit connected in series to an inductor and a capacitor are provided. It is also possible to synthesize high-frequency alternating current output from a single high-frequency power source and supply it to the plasma processing apparatus 30. This case will be described below as a fourth embodiment.

  FIG. 10 is a diagram showing the configuration of the plasma processing system 4 according to the fourth embodiment of the present invention. In addition, about the structure which is the same as that of 1st Embodiment thru | or 3rd Embodiment, or similar, the same code number is attached | subjected and the description is abbreviate | omitted. As shown in FIG. 10, the plasma processing system 4 according to the fourth exemplary embodiment of the present invention includes three DC power supplies 11, 12, 13, an inverter device 23, and a plasma processing device 30. As shown in the figure, the configuration of the three DC power supplies and the configuration of the inverter device 23 are different from the plasma processing system 1 of the first embodiment.

  The DC power supplies 11, 12, and 13 output DC power (DC current) and have the same configuration as the DC power supply 10 of the first embodiment, and thus description thereof is omitted. The inverter device 23 converts the direct current input from the direct current power supplies 11, 12, and 13 into a high frequency alternating current and outputs it. As shown in FIG. 10, the inverter device 23 includes three inverter circuits 231, 232, and 233, a voltage / current detector 201, and a controller 234.

  The inverter circuit 231 (232, 233) includes two switching elements TR1 ′ and TR2 ′ (TR3 ′ and TR4 ′, TR5 ′ and TR6 ′), an inductor L1 ′ (L2 ′, L3 ′), and a capacitor C1 ′. (C2 ′, C3 ′). The switching elements TR1 ′ and TR2 ′ (TR3 ′ and TR4 ′, TR5 ′ and TR6 ′) are the source terminals of the switching elements TR1 ′ (TR3 ′, TR5 ′) and the switching elements TR2 ′ (TR4 ′, TR6 ′). The drain terminal is connected in series. The drain terminals of the switching elements TR1 ′ (TR3 ′, TR5 ′) are connected to the positive side of the DC power supply 11 (12, 13), and the source terminals of the switching elements TR2 ′ (TR4 ′, TR6 ′) are connected to the DC power supply 11 It is connected to the negative electrode side of (12, 13) to form a bridge structure. Each circuit constituted by the two switching elements TR1 'and TR2' (TR3 'and TR4', TR5 'and TR6') connected in series corresponds to a "switching circuit" in claim 2.

  The inductor L1 ′ (L2 ′, L3 ′) and the capacitor C1 ′ (C2 ′, C3 ′) are connected in series to form an LC series resonance circuit, and this LC series resonance circuit is used as the resonance unit LC1. '(LC2', LC3 '). An output line is connected to a connection point between the switching elements TR1 ′ and TR2 ′ (TR3 ′ and TR4 ′, TR5 ′ and TR6 ′), and this output line is connected to the resonance part LC1 ′ (LC2 ′, LC3 ′). Connected to one end. The resonance frequencies of the resonance parts LC1 ′ to LC3 ′ are not limited to approximately three times the switching frequency, as with the resonance parts LC1 to LC3 of the first embodiment, but are set to approximately three times the frequency. It is desirable to keep it. Note that the resonance frequencies of the resonance parts LC1 'to LC3' are all set to the same frequency. Each of the resonance portions LC1 '(LC2', LC3 ') corresponds to a "resonance circuit" in claim 2. The DC power supply 11 (12, 13) and the inverter circuit 231 (232, 233) correspond to the high-frequency power supply.

  The other ends of the resonance parts LC1 ′ to LC3 ′ of the inverter circuits 231 to 233 are connected at one point (connection point D), and the resonance currents ir31 to ir33 flowing through the resonance parts LC1 ′ to LC3 ′ are combined at the connection point D. Is done. The current (load current) IRc4 synthesized at the connection point D is output (supplied) to the plasma processing apparatus 30.

  The control unit 234 has the same configuration as the control unit 202, and generates drive signals Q1 'to Q6' that are input to the switching elements TR1 'to TR6'. Similarly to the control unit 202, the control unit 234 shifts the phases of the drive signals Q1 ′ to Q6 ′ input to the inverter circuits 231 to 233 by 2π / 3 [rad] (= 120 °). I do. In the present embodiment, the control unit 234 is described as one inverter that controls the inverter circuits 231 to 233. However, the control unit 234 may include a control unit for each inverter circuit 231 to 233. Good. Each of the circuits including the inverter circuit 231 (232, 233) and the control unit 234 corresponds to a “resonant inverter circuit” in claim 2.

  In the plasma processing system 4 according to the fourth embodiment configured as described above, the resonance currents ir31 to ir33 output from the inverter circuits 231 to 233 are generated from the conventional triple resonance inverter circuit shown in FIG. Although it is the same as the output resonance current and has a waveform with periodic fluctuations, the resonance currents ir31 to ir33 output from the inverter circuits 231 to 233 are synthesized at the connection point D, so that the plasma processing apparatus The load current IRc4 flowing through 30 is suppressed in periodic fluctuation and becomes a stable high-frequency alternating current.

  As described above, also in the plasma processing system 4 according to the fourth exemplary embodiment of the present invention, the resonance currents ir31 to ir33 output from the inverter circuits 231 to 233 and flowing to the resonance units LC1 ′ to LC3 ′ are synthesized. Then, the plasma processing apparatus 30 is supplied. Thereby, the load current IRc4 flowing through the plasma processing apparatus 30 becomes a stable high-frequency alternating current. Therefore, the inverter device 23 can supply a stable high-frequency alternating current to the plasma processing apparatus 30.

  In the first to fourth embodiments, the case where the inductance of the inductor and the capacitance of the capacitor constituting the LC series resonance circuit are set in advance so as to have a desired resonance frequency has been described as an example. The resonance frequency may be freely changed by adopting a configuration in which both or one of the capacitance and the capacitance can be changed. For example, it can be realized by using a variable inductor whose inductance can be changed or a variable capacitor whose capacitance can be changed. By doing in this way, since the resonance frequency can also be changed according to the switching frequency, the user can freely set the switching frequency. In addition, if the resonance frequency and the switching frequency can be changed, the user can freely set the frequency of the high-frequency alternating current output from the inverter device to the plasma processing apparatus.

  In the first to fourth embodiments, the case where the inductor and the capacitor are connected in series to the plasma processing apparatus 30 (load) has been described as an example. However, the present invention is not limited to this. For example, even when an inductor is connected in series to the plasma processing apparatus 30 (load) and a capacitor is connected in parallel, a high-frequency alternating current N times the switching frequency can be supplied in the same manner. This case will be described below as a fifth embodiment.

  FIG. 11 is a diagram showing a configuration of a plasma processing system 5 according to the fifth embodiment of the present invention. In addition, about the structure which is the same or similar to 1st Embodiment thru | or 4th Embodiment, the same code number is attached | subjected and the description is abbreviate | omitted. Compared with the inverter device 20 (see FIG. 1) of the plasma processing apparatus 1 shown in the first embodiment, the inverter device 24 is different in the connection positions of the capacitors C1 to C3. Further, a capacitor Ccut for cutting a direct current input to the plasma processing apparatus 30 is added. The rest is the same. Each of the circuits including the inductor L1 (L2, L3) and the capacitor C1 (C2, C3) corresponds to the LC circuit according to the eighth aspect.

  In the plasma processing system 5 according to the fifth embodiment configured as described above, each current waveform when the switching frequency of the drive signals Q1 to Q6 is controlled at 13.56 MHz will be described. 12A shows current waveforms of the output currents ir41 to ir43 output from each arm, and FIG. 12B shows an output current IRc5 (load) obtained by combining the output currents ir41 to ir43 at the connection point E. Current IRc5) is shown. As shown in FIG. 12 (a), the output currents ir41 to ir43 output from each arm have a waveform that varies periodically for each switching period. The output currents ir41 to ir43 are synthesized at the connection point E. As a result, as shown in FIG. 12B, the load current IRc5 flowing through the plasma processing apparatus 30 is suppressed in periodic fluctuation and becomes a stable high-frequency alternating current.

  12C shows the FFT analysis result of the output current ir41 in the plasma processing system 5 according to the fifth embodiment, and FIG. 12D shows the load obtained by synthesizing the output currents ir41 to ir43 at the connection point E. The FFT analysis result of current IRc5 is shown. As shown in FIG. 12C, in the output current ir41 output from one arm (same for ir42 and ir43), the highest frequency component of the switching frequency is output, whereas in FIG. In d), the highest frequency component of three times the switching frequency is output. Therefore, it can be seen that an unnecessary frequency component is attenuated in the load current IRc5 obtained by combining the output currents ir41 to ir43.

  In the first to fifth embodiments, the example of combining at one point of the connection point A to the connection point E has been described. However, as long as a plurality of resonance currents are combined and output to the plasma processing apparatus 30, It is not limited to this.

  In the first to fifth embodiments, the case where the inverter device according to the present invention is applied to a plasma processing system has been described as an example. However, the present invention is not limited to this. For example, the present invention can be applied to one that supplies high-frequency AC power to a load other than the plasma processing apparatus. That is, the inverter device according to the present invention functions as an inverter device included in a high-frequency power source that outputs high-frequency AC power.

  The inverter device according to the present invention is not limited to the above embodiment, and the specific configuration of each part can be variously modified without departing from the scope of the claims of the present invention. Various design values (switching frequency, resonance frequency, etc.) used in the description of the above embodiment can be changed in design in various ways.

1, 2, 3, 4, 5 Plasma processing system 10, 11, 12, 13 DC power supply 20, 21, 22, 23, 24 Inverter device 201 Voltage / current detection unit 202, 212, 222, 234 Control unit 231, 232, 233 Inverter circuit 30 Plasma processing apparatus TR1 to TR10, TR1 ′ to TR6 ′ Switching elements L1 to L5, L1 ′ to L3 ′, Lr11 to Lr13 Inductors C1 to C5, C1 ′ to C3 ′, Ccut capacitors Q1 to Q6, Q12, Q14, Q16, Q21 to Q30, Q1 'to Q6' Drive signals ir1 to ir3, ir11 to ir13, ir21 to ir25, ir31 to ir33 Resonant current ir41 to ir43 Output current IRc1, IRc2, IRc3, IRc4, IRc5 Load current

Claims (8)

An inverter device that converts a direct current output from a direct current power source into an alternating current and outputs the alternating current,
Switching in which N arms connected in series with a first switching element connected to the positive side of the DC power source and a second switching element connected to the negative side of the DC power source are connected in parallel to the DC power source Circuit,
Drive signals for switching between the energized state and the de-energized state of the first switching element and the second switching element constituting one arm are shifted in phase by 2π / N [rad] for each arm. Control means for inputting to the first switching element and the second switching element;
A resonance circuit connected to a connection point between the first switching element and the second switching element of each arm;
With
Synthesizing and outputting a resonance current that is an alternating current output from the N resonance circuits;
Inverter device. A switching circuit in which a first switching element connected to a positive electrode side of a DC power supply and a second switching element connected to a negative electrode side of the DC power supply are connected in series;
Control means for inputting a drive signal for switching between an energized state and a non-energized state of the first switching element and the second switching element to the first switching element and the second switching element;
A resonant circuit connected to a connection point between the first switching element and the second switching element of the switching circuit;
N resonant inverter circuits comprising: N connected at the output end of the resonant inverter circuit,
Each of the control means inputs a driving signal whose phase is shifted by 2π / N [rad] for each of the N switching circuits,
Synthesizing and outputting a resonance current which is an alternating current output from each resonance circuit of the N resonance inverter circuits;
Inverter device. N is an odd number of 3 or more,
The inverter apparatus in any one of Claim 1 or Claim 2. When N is 3,
The resonant frequency of the resonant circuit is set to 2.5 to 3.5 times the frequency of the drive signal,
The inverter device according to claim 3. In place of the first switching element, an inductor having a predetermined inductance is provided,
The control means inputs a drive signal for switching between an energized state and a non-energized state of the second switching element
The inverter apparatus as described in any one of Claims 1 thru | or 4. The resonant circuit is an LC series resonant circuit in which an inductor and a capacitor are connected in series.
The inverter apparatus as described in any one of Claim 1 thru | or 5. The resonance circuit can change the inductance of the inductor or the capacitance of the capacitor.
The inverter device according to claim 6. An inverter device that converts a direct current output from a direct current power source into an alternating current and outputs it to a load,
Switching in which N arms connected in series with a first switching element connected to the positive side of the DC power source and a second switching element connected to the negative side of the DC power source are connected in parallel to the DC power source Circuit,
Drive signals for switching between the energized state and the de-energized state of the first switching element and the second switching element constituting one arm are shifted in phase by 2π / N [rad] for each arm. Control means for inputting to the first switching element and the second switching element;
An LC connected to a connection point between the first switching element and the second switching element of each arm, and including an inductor connected in series to the load and a capacitor connected in parallel to the load Circuit,
With
Combining the output currents output from the N LC circuits and outputting them to the load;
Inverter device.