Pulse generation circuit, substrate processing device, and energy regeneration method

Abstract

To use energy efficiently.SOLUTION: A pulse generation circuit includes: a capacitor that has one end connected to a power supply and the other end connected to a ground potential; a transformer in which one end of the primary side is connected to the one end of the capacitor and the secondary side is connected to a load; an inductor that has one end connected to the other end of the primary side of the transformer; a switching element that is connected between the other end of the inductor and the ground potential; a diode that has a cathode connected to the other end of the primary side of the transformer and that has an anode connected to the ground potential; and a control circuit that controls an ON-state and an OFF-state of the switching element. The control circuit controls the switching element to the ON-state, and controls the switching element to the OFF-state during a period in which the direction of current flowing to the primary side of the transformer is reversed, after current flows to the primary side of the transformer.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] Various aspects and embodiments of the present disclosure relate to a pulse generating circuit, a substrate processing apparatus, and an energy recovery method. [Background technology]

[0002] The following Patent Document 1 discloses a pulse power supply including a magnetic reset circuit that uses a saturable reactor as a magnetic switch means and supplies a reset current to a reset winding of the saturable reactor to inversely excite the iron core of the saturable reactor, the magnetic reset circuit comprising: a DC power supply that constantly supplies a reset current to the reset winding; a first reactor that is provided at a reset current output terminal of the DC power supply and that suppresses a surge in a reset current path from entering the DC power supply; a second reactor that is provided between the first reactor and the reset winding and that suppresses an induced current generated in the reset winding; and a diode that is provided in parallel to a series circuit of the second reactor and the reset winding and that circulates the induced current to the second reactor.

[0003] Furthermore, the following Patent Document 2 discloses a snubber circuit that is provided in each arm of a power conversion bridge circuit having at least two sets of upper arms and lower arms formed by main switch elements and suppresses a voltage derived from the operation of the main switch elements, the snubber circuit comprising a diode and a snubber capacitor connected in series, a DC series circuit connected across the set of upper arms and lower arms, and a regenerative circuit having a snubber switch element connected between a connection point between the diode and the snubber capacitor and a connection point between the set of upper arms and lower arms. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-83052 [Patent Document 2] JP 2017-153205 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure provides a pulse generating circuit, a substrate processing apparatus, and an energy regeneration method that enable efficient use of energy. [Means for solving the problem]

[0006] A pulse generating circuit in one aspect of the present disclosure includes a capacitor having one end connected to a power supply and the other end connected to a ground potential, a transformer having one end of its primary side connected to one end of the capacitor and a secondary side connected to a load, an inductor having one end connected to the other end of the primary side of the transformer, a switching element connected between the other end of the inductor and ground potential, a diode having a cathode connected to the other end of the primary side of the transformer and an anode connected to the ground potential, and a control circuit that controls the on and off states of the switching element, wherein the control circuit controls the switching element to an on state and controls the switching element to an off state during a period when the direction of the current flowing in the primary side of the transformer is reversed after a current flows in the primary side of the transformer. Effect of the Invention

[0007] According to various aspects and embodiments of the present disclosure, it is possible to effectively utilize energy. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing an example of a plasma processing apparatus. [Diagram 2] FIG. 2 is a diagram illustrating an example of a configuration of a pulse generating circuit according to the first embodiment. [Diagram 3] FIG. 3 is a flowchart showing an example of the operation of the pulse generating circuit. [Figure 4]FIG. 4 is a timing chart showing an example of changes in each signal in the first embodiment. [Diagram 5] FIG. 5 is a diagram illustrating an example of a configuration of a pulse generating circuit according to the second embodiment. [Figure 6] FIG. 6 is a diagram illustrating an example of a saturable inductor. [Figure 7] FIG. 7 is a diagram showing an example of the configuration of a pulse generating circuit according to the third embodiment. [Figure 8] FIG. 8 is a diagram illustrating an example of an excitation circuit. [Figure 9] FIG. 9 is a diagram showing an example of changes in the voltage Vds and the current Id in the first embodiment. [Figure 10] FIG. 10 is a diagram showing an example of changes in voltage Vds and current Id in the comparative example. [Figure 11] FIG. 11 is a diagram showing an example of changes in voltage Vds and current Id in the third embodiment. [Figure 12] FIG. 12 is a timing chart showing an example of changes in each signal in the third embodiment. [Figure 13] FIG. 13 is a diagram showing an example of the configuration of a pulse generating circuit according to the fourth embodiment.

[0009] Hereinafter, embodiments of a pulse generating circuit, a substrate processing apparatus, and an energy recovery method will be described in detail with reference to the drawings. Note that the pulse generating circuit, the substrate processing apparatus, and the energy recovery method disclosed below are not limited to the embodiments.

[0010] However, with the recent increase in awareness of environmental issues, there is a demand for power saving in devices. Power saving is also required in pulse generating circuits. In view of this, the present disclosure provides a technique for enabling efficient use of energy.

[0011] [Configuration of plasma processing apparatus 1] An example of the configuration of a plasma processing system will be described below. Fig. 1 is a diagram for explaining an example of the configuration of a capacitively coupled plasma processing apparatus 1. The plasma processing apparatus 1 is an example of a substrate processing apparatus.

[0012] The plasma processing system includes a capacitively coupled plasma processing device 1 and a controller 2. The capacitively coupled plasma processing device 1 includes a plasma processing chamber 10, a gas supply 20, a power supply 30, and an exhaust system 40. The plasma processing device 1 also includes a substrate support 11 and a gas inlet. The gas inlet is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas inlet includes a shower head 13. The substrate support 11 is disposed in the plasma processing chamber 10. The shower head 13 is disposed above the substrate support 11. In one embodiment, the shower head 13 constitutes at least a part of a ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the shower head 13, a sidewall 10a of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space 10s and at least one gas exhaust port for exhausting gas from the plasma processing space. The plasma processing chamber 10 is grounded. The showerhead 13 and the substrate support 11 are electrically insulated from the housing of the plasma processing chamber 10.

[0013] The substrate support 11 includes a main body 111 and a ring assembly 112. The main body 111 has a central region 111a for supporting the substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of the substrate W. The annular region 111b of the main body 111 surrounds the central region 111a of the main body 111 in a plan view. The substrate W is disposed on the central region 111a of the main body 111, and the ring assembly 112 is disposed on the annular region 111b of the main body 111 so as to surround the substrate W on the central region 111a of the main body 111. Therefore, the central region 111a is also called a substrate support surface for supporting the substrate W, and the annular region 111b is also called a ring support surface for supporting the ring assembly 112.

[0014] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The conductive member of the base 1110 may function as a lower electrode. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b disposed within the ceramic member 1111a. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Note that other members surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member, may have the annular region 111b. In this case, the ring assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating member, or may be disposed on both the electrostatic chuck 1111 and the annular insulating member. Also, at least one RF / DC electrode coupled to a radio frequency (RF) power source 31 and / or a direct current (DC) power source 32 described later may be disposed in the ceramic member 1111a. In this case, the at least one RF / DC electrode functions as a lower electrode. When a bias RF signal and / or a DC signal described later is supplied to the at least one RF / DC electrode, the RF / DC electrode is also called a bias electrode. Note that the conductive member of the base 1110 and the at least one RF / DC electrode may function as a plurality of lower electrodes. Also, the electrostatic electrode 1111b may function as a lower electrode. Thus, the substrate support 11 includes at least one lower electrode.

[0015] The ring assembly 112 includes one or more annular members. In one embodiment, the one or more annular members include one or more edge rings and at least one cover ring. The edge rings are formed of a conductive or insulating material, and the cover rings are formed of an insulating material.

[0016] The substrate support 11 may also include a temperature adjustment module configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate to a target temperature. The temperature adjustment module may include a heater, a heat transfer fluid, a flow passage 1110a, or a combination thereof. A heat transfer fluid such as a brine or a gas flows through the flow passage 1110a. In one embodiment, the flow passage 1110a is formed in the base 1110, and one or more heaters are disposed in the ceramic member 1111a of the electrostatic chuck 1111. The substrate support 11 may also include a heat transfer gas supply configured to supply a heat transfer gas to a gap between the back surface of the substrate W and the central region 111a.

[0017] The shower head 13 is configured to introduce at least one processing gas from the gas supply unit 20 into the plasma processing space 10s. The shower head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and multiple gas inlets 13c. The processing gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s from the multiple gas inlets 13c. The shower head 13 also includes at least one upper electrode. Note that the gas introduction unit may include, in addition to the shower head 13, one or more side gas injectors (SGI) attached to one or more openings formed in the sidewall 10a.

[0018] The gas supply 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply 20 is configured to supply at least one process gas from a respective gas source 21 through a respective flow controller 22 to the showerhead 13. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply 20 may include one or more flow modulation devices to modulate or pulse a flow rate of the at least one process gas.

[0019] The power source 30 includes an RF power source 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power source 31 is configured to supply at least one RF signal (RF power) to at least one lower electrode and / or at least one upper electrode. This causes a plasma to be formed from at least one processing gas supplied to the plasma processing space 10s. Thus, the RF power source 31 can function as at least a part of a plasma generating unit configured to generate a plasma from one or more processing gases in the plasma processing chamber 10. In addition, a bias potential is generated on the substrate W by supplying a bias RF signal to the at least one lower electrode, and ion components in the formed plasma can be attracted to the substrate W.

[0020] In one embodiment, the RF power supply 31 includes a first RF generating unit 31a and a second RF generating unit 31b. The first RF generating unit 31a is coupled to at least one lower electrode and / or at least one upper electrode via at least one impedance matching circuit, and is configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. In one embodiment, the first RF generating unit 31a may be configured to generate a plurality of source RF signals having different frequencies. The generated one or more source RF signals are supplied to at least one lower electrode and / or at least one upper electrode.

[0021] The second RF generating unit 31b is coupled to at least one lower electrode via at least one impedance matching circuit and configured to generate a bias RF signal (bias RF power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF generating unit 31b may be configured to generate a plurality of bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. Also, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0022] The power supply 30 may also include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generator 32a and a second DC generator 32b. In one embodiment, the first DC generator 32a is connected to at least one lower electrode and configured to generate a first DC signal. The generated first bias DC signal is applied to the at least one lower electrode. In one embodiment, the second DC generator 32b is connected to at least one upper electrode and configured to generate a second DC signal. The generated second DC signal is applied to the at least one upper electrode.

[0023] In this embodiment, at least one of the first and second DC signals is pulsed. A sequence of voltage pulses is applied to at least one lower electrode and / or at least one upper electrode. The voltage pulses may have a rectangular, trapezoidal, triangular or combination thereof pulse waveform. In this embodiment, a pulse generating circuit for generating a sequence of voltage pulses from the DC signal is connected between the first DC generating unit 32a and at least one lower electrode. Thus, the first DC generating unit 32a and the pulse generating circuit constitute a voltage pulse generating unit. When the second DC generating unit 32b and the pulse generating circuit constitute a voltage pulse generating unit, the voltage pulse generating unit is connected to at least one upper electrode. The voltage pulses may have a positive polarity or a negative polarity. Also, the sequence of voltage pulses may include one or more positive polarity voltage pulses and one or more negative polarity voltage pulses within one period. The first and second DC generating units 32a, 32b may be provided in addition to the RF power supply 31, or the first DC generating unit 32a may be provided in place of the second RF generating unit 31b.

[0024] The exhaust system 40 may be connected to, for example, a gas exhaust port 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is adjusted by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0025] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to execute various steps described in the present disclosure. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to execute various steps described herein. In one embodiment, a part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 may include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 is realized, for example, by a computer 2a. The processing unit 2a1 may be configured to perform various control operations by reading a program from the storage unit 2a2 and executing the read program. This program may be stored in the storage unit 2a2 in advance, or may be acquired via a medium when necessary. The acquired program is stored in the storage unit 2a2 and is read from the storage unit 2a2 by the processing unit 2a1 and executed. The medium may be various storage media readable by the computer 2a, or may be a communication line connected to the communication interface 2a3. The processing unit 2a1 may be a CPU (Central Processing Unit). The storage unit 2a2 may include a random access memory (RAM), a read only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a local area network (LAN).

[0026] (First embodiment) [Configuration of pulse generating circuit 50] 2 is a diagram showing an example of the configuration of a pulse generating circuit 50 in the first embodiment. The pulse generating circuit 50 in this embodiment includes a capacitor 52, a transformer 53, an inductor 54, a switching element 55, a gate circuit 56, and a diode 57. The control unit 2 and the gate circuit 56 are an example of a control circuit.

[0027] One end of the capacitor 52 is connected to the charger 51, and the other end is connected to a ground potential. The charger 51 is an example of a power source. The charging of the capacitor 52 by the charger 51 is controlled by the control unit 2. The voltage of the capacitor 52 is V c The transformer 53 has one end of the primary side connected to one end of the capacitor 52, and the secondary side connected to the load 60. The current flowing from the capacitor 52 to the transformer 53 is defined as I m One end of the inductor 54 is connected to the other end of the primary side of the transformer 53.

[0028] The switching element 55 is connected between the other end of the inductor 54 and the ground potential. In this embodiment, the switching element 55 is an n-channel MOSFET. In addition, the switching element 55 is preferably a MOSFET using silicon carbide. Note that the switching element 55 may be a p-channel MOSFET or an IGBT.

[0029] The gate circuit 56 controls the on / off state of the switching element 55 by controlling a gate voltage V g In this embodiment, the gate voltage V g When the voltage V g When the trigger signal is input from the control unit 2 to the gate circuit 56, the gate voltage V output from the gate circuit 56 to the switching element 55 is g There is a delay ΔT between g exists.

[0030] The cathode of the diode 57 is connected to the other end of the primary side of the transformer 53, and the anode of the diode 57 is connected to the ground potential. The current flowing from the diode 57 to the transformer 53 is I r It is preferable that the diode 57 is a diode that operates at high speed and has excellent reverse recovery characteristics. For example, it is preferable that the diode 57 is a fast recovery diode or a Schottky barrier diode.

[0031] [Operation of the pulse generating circuit 50] Fig. 3 is a flowchart showing an example of the operation of the pulse generating circuit 50. Each process illustrated in Fig. 3 is realized by the control unit 2 controlling each unit of the pulse generating circuit 50. The following description will be given with reference to the timing chart illustrated in Fig. 4. Note that before the start of the flowchart illustrated in Fig. 3, the switching element 55 is controlled to be in the off state.

[0032] First, the charger 51 is controlled to charge the capacitor 52 (step S10). In step S10, the charger 51 starts charging the capacitor 52 at, for example, timing t1 shown in FIG. 4. Then, the voltage V of the capacitor 52 is c At time t2 when the drain-source voltage V reaches a predetermined voltage, charging of the capacitor 52 by the charger 51 is stopped. In addition, since the switching element 55 is controlled to be in the off state, the drain-source voltage V ds voltage V c It rises with.

[0033] Next, the switching element 55 is controlled to be in an ON state (step S11). Step S11 is an example of the process a). In step S11, for example, at a timing t3 shown in FIG. 4, a trigger signal instructing the switching element 55 to be in an ON state is sent from the control unit 2. The gate circuit 56 is supplied with a delay ΔT g At time t4, when the time has elapsed, the high gate voltage V g is applied to the gate terminal of the switching element 55. A high gate voltage V g By applying the current I to the capacitor 52, the switching element 55 is controlled to be in the on state. As a result, as shown in FIG. 4, for example, a current I mAlso, the voltage V of the switching element 55 ds is almost 0.

[0034] Here, the current I m Attenuates while oscillating at a resonance frequency caused by the capacitance of the capacitor 52, the inductance of the transformer 53, the inductance of the inductor 54, the parasitic capacitance of the wiring, and the parasitic inductance of the wiring. r is the current I m 4 shows the resonance period of

[0035] Next, it is determined whether or not a predetermined period ΔT0 has elapsed since the supply of the trigger signal was started (step S12). If the predetermined period ΔT0 has not elapsed since the supply of the trigger signal was started (step S12: No), the process shown in step S12 is executed again.

[0036] On the other hand, if a predetermined period ΔT0 has elapsed since the supply of the trigger signal started (step S12: Yes), the switching element 55 is controlled to be in the OFF state (step S13). Steps S12 and S13 are an example of process b). In step S13, for example, at timing t5 shown in FIG. 4, a trigger signal instructing the switching element 55 to be in the OFF state is supplied from the control unit 2 to the gate circuit 56. The gate circuit 56 receives a delay ΔT g At time t6 after t1 has elapsed, the gate voltage V g is applied to the gate terminal of the switching element 55. A low gate voltage V g When this voltage is applied to the switching element 55, an off surge occurs in the switching element 55, and the voltage V ds vibrates greatly.

[0037] Next, it is determined whether or not to end the pulse generation (step S14). If the pulse generation is not to be ended (step S14: No), the process shown in step S10 is executed again. On the other hand, if the pulse generation is to be ended (step S14: Yes), the process shown in this flowchart ends.

[0038] In this embodiment, the timing t6 at which the switching element 55 is controlled to be in the off state is the timing at which the current I m The current I m The timing t6 is the time when the current I m The timing t when the direction of 51 from current I m In other words, the length of the period ΔT0 of the trigger signal instructing the switching element 55 to be in the ON state is equal to or longer than the resonance period T r longer than 1 / 2 of the resonant period T r This allows the regenerative current I r flows, and the regenerative current I r As a result, for example, as shown in FIG. 4, during the period from timing t6 to timing t7 when charging by the charger 51 is not performed, the capacitor 52 is charged, and the voltage V c This will increase the efficiency of energy usage.

[0039] The timing t6 at which the switching element 55 is controlled to be in the OFF state is the timing at which the current I m The timing t when the direction of 51 from current I m The timing t7 at which the direction of the 51 This is preferable because the timing is close to the regenerative current I r can be used to charge the capacitor 52.

[0040] Here, if the diode 57 is not provided between the transformer 53 and the switching element 55, when the switching element 55 is controlled to the off state, the regenerative current I r Therefore, the voltage V of the capacitor 52 after the switching element 55 is controlled to the OFF state at the timing t6 is c 4, is maintained at the voltage at time t6. Therefore, when charging of the capacitor 52 by the charger 51 is resumed at time t8, the voltage V c gradually increases, and at time t 10 At this point, a predetermined voltage is reached.

[0041] On the other hand, in this embodiment, since the diode 57 is provided between the transformer 53 and the switching element 55, the regenerative current I r flows, and the regenerative current I r Then, when the charging of the capacitor 52 by the charger 51 is resumed at the timing t8, a certain amount of charge is stored in the capacitor 52, so that the voltage V c In the example of FIG. 4, the voltage V of the capacitor 52 in this embodiment rises to the predetermined voltage more quickly. c is the timing t 10 The predetermined voltage is reached at an earlier timing t9, which allows the next pulse to be output more quickly.

[0042] In the example of Figure 4, the current I m During the first reversal of the direction of the regenerative current I r In the example shown, the capacitor 52 is charged by a current I m Even during the period when the direction of the regenerative current I r Therefore, by providing the diode 57, the current I m During the period when the direction of the regenerative current I rThis allows the capacitor 52 to be charged, thereby making it possible to effectively utilize energy.

[0043] The first embodiment has been described above. As described above, the pulse generating circuit (pulse generating circuit 50) in this embodiment includes a capacitor (capacitor 52) having one end connected to a power source (charger 51) and the other end connected to a ground potential, a transformer (transformer 53) having one end of the primary side connected to one end of the capacitor and a secondary side connected to a load (load 60), an inductor (inductor 54) having one end connected to the other end of the primary side of the transformer, a switching element (switching element 55) connected between the other end of the inductor and the ground potential, a diode (57) having a cathode connected to the other end of the primary side of the transformer and an anode connected to the ground potential, and a control circuit (plasma processing device 1 and gate circuit 56) for controlling the on and off states of the switching element, and the control circuit controls the switching element to the on state and controls the switching element to the off state during a period in which a current flows in the primary side of the transformer and then the direction of the current flowing in the primary side of the transformer is reversed. This allows for efficient use of energy.

[0044] In the above-described embodiment, the switching element is a MOSFET. Alternatively, the switching element may be a MOSFET using silicon carbide, which enables high-speed switching.

[0045] Furthermore, the diode in the above-described embodiment is a fast recovery diode or a Schottky barrier diode, which allows the regenerative current to flow quickly to the capacitor.

[0046] Further, the substrate processing apparatus in the above-described embodiment includes a chamber (plasma processing chamber 10) having a gas supply port (gas supply port 13a) and a gas exhaust port (gas exhaust port 10e) and accommodating a substrate (substrate W), and a pulse generating circuit (pulse generating circuit 50) that processes the substrate using plasma by supplying pulsed power into the chamber to convert gas supplied through the gas supply port into plasma in the chamber. The pulse generating circuit includes a capacitor (capacitor 52) having one end connected to a power source (charger 51) and the other end connected to a ground potential, a transformer (transformer 53) having one end of the primary side connected to one end of the capacitor and a secondary side connected to a load (load 60), an inductor (inductor 54) having one end connected to the other end of the primary side of the transformer, a switching element (switching element 55) connected between the other end of the inductor and the ground potential, a diode (57) having a cathode connected to the other end of the primary side of the transformer and an anode connected to the ground potential, and a control circuit (plasma processing device 1 and gate circuit 56) for controlling the on and off states of the switching element, and the control circuit controls the switching element to the on state and controls the switching element to the off state during a period in which a current flows in the primary side of the transformer and then the direction of the current flowing in the primary side of the transformer is reversed after the current flows in the primary side of the transformer. This allows for efficient use of energy.

[0047] In the energy regeneration method in the above-mentioned embodiment, a pulse generation circuit (pulse generation circuit 50) includes a capacitor (capacitor 52) having one end connected to a power source (charger 51) and the other end connected to a ground potential, a transformer (transformer 53) having one end of the primary side connected to one end of the capacitor and a secondary side connected to a load (load 60), an inductor (inductor 54) having one end connected to the other end of the primary side of the transformer, a switching element (switching element 55) connected between the other end of the inductor and the ground potential, a diode (57) having a cathode connected to the other end of the primary side of the transformer and an anode connected to the ground potential, and a control circuit (plasma processing device 1 and gate circuit 56) for controlling the on and off states of the switching element. In the step a), the switching element is controlled to be in the on state. In the step b), after the switching element is turned on to cause a current to flow in the primary side of the transformer, the switching element is controlled to be in the off state during a period in which the direction of the current flowing in the primary side of the transformer is reversed. This makes it possible to effectively utilize energy.

[0048] Second embodiment In the first embodiment, an inductor 54 is provided in the pulse generating circuit 50, but in the second embodiment, a saturable inductor 54' is provided instead of the inductor 54. The following description will focus on the differences from the first embodiment.

[0049] [Configuration of pulse generating circuit 50] 5 is a diagram showing an example of the configuration of a pulse generating circuit 50 in the second embodiment. The pulse generating circuit 50 in this embodiment includes a capacitor 52, a transformer 53, a saturable inductor 54', a switching element 55, a gate circuit 56, and a diode 57. One end of the saturable inductor 54' is connected to the other end of the primary side of the transformer 53, and the other end is grounded via the switching element 55.

[0050] The saturable inductor 54' has a structure in which an electric wire is wound around a core of, for example, ferrite or a cobalt-based amorphous alloy. Specifically, the saturable inductor 54' is a toroidal coil in which an electric wire 541 is wound around an annular toroidal core 540, as shown in Fig. 6. By providing the saturable inductor 54' instead of the inductor 54, the switching loss of the switching element 55 can be reduced.

[0051] (Third embodiment) The third embodiment differs from the second embodiment in that an excitation circuit 58 that excites a saturable inductor 54' is further provided. The following description will focus on the differences from the second embodiment.

[0052] [Configuration of pulse generating circuit 50] 7 is a diagram showing an example of the configuration of a pulse generating circuit 50 in the third embodiment. The pulse generating circuit 50 in this embodiment includes a capacitor 52, a transformer 53, a saturable inductor 54', a switching element 55, a gate circuit 56, a diode 57, and an excitation circuit 58. The excitation circuit 58 excites the saturable inductor 54' so that a magnetic field is generated in the opposite direction to the magnetic field generated by the current flowing through the saturable inductor 54' when the switching element 55 is turned on.

[0053] 8 is a diagram showing an example of the excitation circuit 58. The excitation circuit 58 has an inductor 580, an inductor 581, a resistor 582, a diode 583, an inductor 584, and a DC power supply 585. The inductor 581, the resistor 582, and the inductor 584 are connected in series between the positive side of the DC power supply 585 and one end of the inductor 580. The other end of the inductor 580 is connected to the negative side of the DC power supply 585. The cathode of the diode 583 is connected to a node between the resistor 582 and the inductor 584, and the anode of the diode 583 is connected to the negative side of the DC power supply 585.

[0054] The saturable inductor 54' is excited by a magnetic field generated in the inductor 580 by a current supplied from the DC power supply 585 to the inductor 580 via the inductor 584, the resistor 582, and the inductor 581. This makes it possible to lengthen the time required for the magnetic flux density of the saturable inductor 54' to become saturated when the switching element 55 transitions to the on state. As a result, the current I d In addition, since the impedance of the saturable inductor 54' can be kept high until the magnetic flux density is saturated, the voltage V of the switching element 55 can be delayed. ds can be lowered quickly.

[0055] Here, the voltage V in the switching element 55 of the first embodiment ds and current I d For example, the voltage V changes as shown in FIG. 9. ds and current I d 9 is a diagram showing an example of a change in the voltage V ds Falling edge of and current I d This coincides with the rise of the

[0056] FIG. 10 shows the voltage V ds and current I d 10 is a diagram showing an example of a change in the voltage V during a period ΔT2. In the comparative example, a solenoid coil in which an electric wire is wound around a rod-shaped core such as ferrite is used instead of the inductor 54. In the example of FIG. ds Falling edge of and current I d Comparing Figure 9 and Figure 10, the voltage V ds Falling edge of and current I d The overlap with the rising edge of the first pulse is smaller in the comparative example than in the first embodiment. That is, the switching loss is smaller in the comparative example than in the first embodiment.

[0057] FIG. 11 shows the voltage V ds and current Id 11 is a diagram showing an example of a change in the voltage V during a period ΔT3. In the third embodiment, a toroidal coil in which an electric wire is wound around a core such as ferrite is used as the saturable inductor 54'. In the example of FIG. ds Falling edge of and current I d Comparing Figures 9 to 11, the voltage V ds Falling edge of and current I d In other words, the third embodiment has the smallest switching loss among the first embodiment, the comparative example, and the third embodiment.

[0058] 12 is a timing chart showing an example of changes in each signal in the third embodiment. The following description will focus on the differences from FIG.

[0059] The gate circuit 56 is operated with a delay ΔT from the timing t3 when the supply of the trigger signal is started. g At time t4, when the time has elapsed, the high gate voltage V g is applied to the gate terminal of the switching element 55. A high gate voltage V g When the switching element 55 is applied, the switching element 55 is controlled to be in the ON state, and a current starts to flow through the saturable inductor 54'. However, it takes time ΔT until the magnetic flux density of the core of the saturable inductor 54' becomes saturated. s During this period, the impedance of the saturable inductor 54' is high, so that the current I d Therefore, the current I m The rise of period ΔT s delay, current I m For example, at timing t 41 It starts flowing from

[0060] Also, at timing t6, the gate voltage V gis applied to the gate terminal of the switching element 55, and the switching element 55 is controlled to be in the off state, an off surge occurs in the switching element 55. However, in this embodiment, a saturable inductor 54' is connected to the switching element 55. Therefore, compared to the pulse generating circuit 50 of the first embodiment in which the inductor 54 is connected to the switching element 55, the voltage V ds (See FIG. 4 and FIG. 12.) This makes it possible to prevent damage to the switching element 55 due to an off surge.

[0061] (Fourth embodiment) In the fourth embodiment, as shown in Fig. 13, for example, a magnetic pulse compression circuit 59 is provided between the transformer 53. This makes it possible to narrow the width of the pulse supplied to the load 60. Note that, although one magnetic pulse compression circuit 59 is provided between the transformer 53 in the example of Fig. 13, the disclosed technology is not limited to this, and a plurality of magnetic pulse compression circuits 59 may be provided between the transformer 53.

[0062] [others] It should be noted that the technology disclosed in the present application is not limited to the above-described embodiment, and various modifications are possible within the scope of the gist thereof.

[0063] For example, in the above embodiment, the plasma processing apparatus 1 that performs processing using a capacitively coupled plasma (CCP) as an example of a plasma source has been described, but the plasma source is not limited to this. Examples of plasma sources other than the capacitively coupled plasma include inductively coupled plasma (ICP), microwave excited surface wave plasma (SWP), electron cyclotron resonance plasma (ECP), and helicon wave excited plasma (HWP).

[0064] It should be noted that the embodiments disclosed herein are illustrative in all respects and should not be construed as limiting. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims.

[0065] Furthermore, the following supplementary notes are disclosed regarding the above embodiment.

[0066] (Appendix 1) a capacitor having one end connected to a power supply and the other end connected to a ground potential; a transformer having a primary side connected to one end of the capacitor and a secondary side connected to a load; an inductor having one end connected to the other end of the primary side of the transformer; a switching element connected between the other end of the inductor and a ground potential; a diode having a cathode connected to the other end of the primary side of the transformer and an anode connected to a ground potential; a control circuit for controlling the on and off states of the switching element; Equipped with The control circuit includes: a pulse generating circuit that controls the switching element to an on state, and controls the switching element to an off state during a period in which a current flows through the primary side of the transformer and then a direction of the current flowing through the primary side of the transformer is reversed after the current flows through the primary side of the transformer. (Appendix 2) 2. The pulse generating circuit of claim 1, wherein the inductor is a saturable inductor. (Appendix 3) The pulse generating circuit of claim 2, further comprising an excitation circuit that excites the saturable inductor so as to generate a magnetic field in the opposite direction to the magnetic field generated by the current flowing through the saturable inductor when the switching element is turned on. (Appendix 4) 4. The pulse generating circuit according to claim 2 or 3, wherein the inductor is a toroidal coil in which an electric wire is wound around an annular core. (Appendix 5) 5. The pulse generating circuit according to claim 1, wherein the switching element is a MOSFET. (Appendix 6) 6. The pulse generating circuit according to claim 5, wherein the switching element is a MOSFET using silicon carbide. (Appendix 7) 7. The pulse generating circuit according to claim 1, wherein the diode is a fast recovery diode or a Schottky barrier diode. (Appendix 8) 8. The pulse generating circuit of claim 1, further comprising a magnetic pulse compression circuit provided between a secondary side of the transformer and a load. (Appendix 9) a chamber having a gas supply port and a gas exhaust port and configured to accommodate the substrate; a pulse generating circuit for supplying a pulse-like power into the chamber to convert the gas supplied through the gas supply port into plasma in the chamber, thereby processing the substrate using the plasma; Equipped with The pulse generating circuit includes: a capacitor having one end connected to a power supply and the other end connected to a ground potential; a transformer having a primary side connected to one end of the capacitor and a secondary side connected to a load; an inductor having one end connected to the other end of the primary side of the transformer; a switching element connected between the other end of the inductor and a ground potential; a diode having a cathode connected to the other end of the primary side of the transformer and an anode connected to a ground potential; a control circuit for controlling the on and off states of the switching element; having The control circuit includes: the switching element is controlled to an ON state, and after a current flows through a primary side of the transformer, the switching element is controlled to an OFF state during a period in which a direction of the current flowing through the primary side of the transformer is reversed. (Appendix 10) a capacitor having one end connected to a power supply and the other end connected to a ground potential; a transformer having a primary side connected to one end of the capacitor and a secondary side connected to a load; an inductor having one end connected to the other end of the primary side of the transformer; a switching element connected between the other end of the inductor and a ground potential; a diode having a cathode connected to the other end of the primary side of the transformer and an anode connected to a ground potential; a control circuit for controlling the on and off states of the switching element; In a pulse generating circuit having The control circuit, a) controlling the switching element to an on state; b) controlling the switching element to an off state during a period in which a direction of the current flowing through the primary side of the transformer is reversed after the switching element is turned on and a current flows through the primary side of the transformer; This is an energy recovery method. [Explanation of symbols]

[0067] W substrate 1. Plasma processing equipment 10 Plasma Processing Chamber 10a side wall 10e Gas exhaust port 10s Plasma treatment space 11 Substrate support 111 Main body 111a Central area 111b Annular region 1110 Foundation 1110a Flow path 1111 Electrostatic Chuck 1111a Ceramic components 1111b Electrostatic electrode 112 Ring Assembly 13. Shower Head 13a Gas supply port 13b Gas diffusion chamber 13c Gas inlet 20 Gas supply section 21 Gas Source 22 Flow Controller 30 power supply 31 RF power supply 31a First RF generation unit 31b Second RF generation unit 32 DC power supply 32a First DC generation unit 32b Second DC generation section 40 Exhaust system 2. Control section 2a Computer 2a1 Processing section 2a2 Storage section 2a3 Communication Interface 50 Pulse generating circuit 51 Charger 52 Capacitor 53 Trans 54 Inductor 540 Toroidal Core 541 Electric wire 54' Saturable Inductor 55 Switching element 56 Gate Circuit 57 Diode 58 Excitation circuit 580 Inductor 581 Inductor 582 Resistance 583 Diode 584 Inductor 585 DC power supply 59 Magnetic Pulse Compression Circuit 60 Load

Claims

1. a capacitor having one end connected to a power supply and the other end connected to a ground potential; a transformer having a primary side connected to one end of the capacitor and a secondary side connected to a load; an inductor having one end connected to the other end of the primary side of the transformer; a switching element connected between the other end of the inductor and a ground potential; a diode having a cathode connected to the other end of the primary side of the transformer and an anode connected to a ground potential; a control circuit for controlling the on and off states of the switching element; Equipped with The control circuit includes: a pulse generating circuit that controls the switching element to an ON state and controls the switching element to an OFF state during a period in which a current flows through the primary side of the transformer and then a direction of the current flowing through the primary side of the transformer is reversed after the current flows through the primary side of the transformer.

2. 2. The pulse generating circuit of claim 1, wherein the inductor is a saturable inductor.

3. 3. The pulse generating circuit according to claim 2, further comprising an excitation circuit that excites the saturable inductor so as to generate a magnetic field in an opposite direction to a magnetic field generated by a current flowing through the saturable inductor when the switching element is turned on.

4. 4. The pulse generating circuit according to claim 2, wherein the inductor is a toroidal coil having an electric wire wound around an annular core.

5. 2. The pulse generating circuit according to claim 1, wherein the switching element is a MOSFET.

6. 6. The pulse generating circuit according to claim 5, wherein the switching element is a MOSFET using silicon carbide.

7. 2. The pulse generating circuit according to claim 1, wherein the diode is a fast recovery diode or a Schottky barrier diode.

8. 2. The pulse generating circuit of claim 1, further comprising a magnetic pulse compression circuit provided between the secondary side of the transformer and a load.

9. a chamber having a gas supply port and a gas exhaust port and configured to accommodate the substrate; a pulse generating circuit for supplying a pulse-like power into the chamber to convert the gas supplied through the gas supply port into plasma in the chamber, thereby processing the substrate using the plasma; Equipped with The pulse generating circuit includes: a capacitor having one end connected to a power supply and the other end connected to a ground potential; a transformer having a primary side connected to one end of the capacitor and a secondary side connected to a load; an inductor having one end connected to the other end of the primary side of the transformer; a switching element connected between the other end of the inductor and a ground potential; a diode having a cathode connected to the other end of the primary side of the transformer and an anode connected to a ground potential; a control circuit for controlling the on and off states of the switching element; having The control circuit includes: the switching element is controlled to an ON state, and after a current flows through a primary side of the transformer, the switching element is controlled to an OFF state during a period in which a direction of the current flowing through the primary side of the transformer is reversed.

10. a capacitor having one end connected to a power supply and the other end connected to a ground potential; a transformer having a primary side connected to one end of the capacitor and a secondary side connected to a load; an inductor having one end connected to the other end of the primary side of the transformer; a switching element connected between the other end of the inductor and a ground potential; a diode having a cathode connected to the other end of the primary side of the transformer and an anode connected to a ground potential; a control circuit for controlling the on and off states of the switching element; In a pulse generating circuit having The control circuit, a) controlling the switching element to an on state; b) controlling the switching element to an off state during a period in which a direction of the current flowing through the primary side of the transformer is reversed after the switching element is turned on and a current flows through the primary side of the transformer; This is an energy recovery method.

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