Plasma processing apparatus

Abstract

To provide a technology for suitably adjusting energy of ions that are generated during plasma generation and directed toward a lower electrode.SOLUTION: In one exemplary embodiment, there is provided a plasma processing apparatus. In the plasma processing apparatus, a high-frequency power supply is electrically connected to an upper electrode and configured to generate a plasma of processing gas by applying a high-frequency voltage to the upper electrode; a first meter is configured to measure a potential waveform of the upper electrode; a second meter is configured to measure a potential waveform of a lower electrode; a detector detects a voltage waveform obtained by subtracting a second potential waveform measured by the second meter from a first potential waveform measured by the first meter; an impedance adjusting device is configured to adjust an impedance of the lower electrode; and a control device is configured to control the impedance adjusting device to adjust the impedance of the lower electrode based on the voltage waveform detected by the detector.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Exemplary embodiments of the present disclosure relate to a plasma processing apparatus.

Background Art

[0002] Plasma processing is performed as a kind of substrate processing. In plasma processing, a substrate is processed by chemical species from plasma generated in a chamber by high frequency. Chemical species in the plasma include ions and radicals. The substrate on the stage can be damaged by the ion energy applied by high frequency. The ion energy can increase or decrease according to the value of the impedance of the lower electrode (stage having the lower electrode). Patent Document 1 discloses a technique for matching the high frequency power source, the load side of the high frequency power source, and the impedance to suppress the reflected wave to the high frequency power source.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a technique for suitably adjusting the energy of ions directed to a lower electrode generated during plasma generation.

Means for Solving the Problems

[0005] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, an upper electrode, a gas supply unit, a high-frequency power source, a first measuring instrument, a second measuring instrument, a detector, an impedance adjusting device, and a control device. The lower electrode may be included in a substrate support portion configured to be provided in the chamber and on which a substrate is placed. The upper electrode may be provided in the chamber and arranged to face the lower electrode. The gas supply unit may be configured to supply a processing gas between the upper electrode and the lower electrode. The high-frequency power source may be electrically connected to the upper electrode and configured to generate plasma of the processing gas by applying a high-frequency voltage to the upper electrode. The first measuring instrument may be configured to measure the potential waveform of the upper electrode. The second measuring instrument may be configured to measure the potential waveform of the lower electrode. The detector may be configured to detect a voltage waveform obtained by subtracting the second potential measured by the second measuring instrument from the first potential waveform measured by the first measuring instrument. The impedance adjusting device may be configured to adjust the impedance of the lower electrode. The control device may be configured to control the impedance adjusting device to adjust the impedance of the lower electrode based on the voltage waveform detected by the detector.

Advantages of the Invention

[0006] According to one exemplary embodiment, the energy of ions directed toward the lower electrode generated during plasma generation can be suitably adjusted.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0008] Hereinafter, various exemplary embodiments will be described.

[0009] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, an upper electrode, a gas supply unit, a high-frequency power source, a first measuring instrument, a second measuring instrument, a detector, an impedance adjusting device, and a control device. The lower electrode may be included in a substrate support portion configured to be provided in the chamber and on which a substrate is placed. The upper electrode may be provided in the chamber and arranged to face the lower electrode. The gas supply unit may be configured to supply a processing gas between the upper electrode and the lower electrode. The high-frequency power source may be electrically connected to the upper electrode and configured to generate plasma of the processing gas by applying a high-frequency voltage to the upper electrode. The first measuring instrument may be configured to measure the potential waveform of the upper electrode. The second measuring instrument may be configured to measure the potential waveform of the lower electrode. The detector may be configured to detect a voltage waveform obtained by subtracting the second potential measured by the second measuring instrument from the first potential waveform measured by the first measuring instrument. The impedance adjusting device may be configured to adjust the impedance of the lower electrode. The control device may be configured to control the impedance adjusting device to adjust the impedance of the lower electrode based on the voltage waveform detected by the detector.

[0010] Therefore, the impedance of the lower electrode is adjusted according to the voltage waveform obtained by subtracting the second potential waveform of the lower electrode from the first potential waveform of the upper electrode. Thus, the energy of the ions traveling toward the lower electrode generated during plasma generation can be adjusted. Since the sheath voltage on the lower electrode that provides energy to the ions increases and decreases in correlation with the voltage between the upper and lower electrodes, the optimization of the ion energy becomes possible more so than when adjusting the impedance of the lower electrode based on the current flowing through the lower electrode. In particular, since it is possible to adjust the sheath voltage on the lower electrode to be lower, the adjustment of the ion energy in a lower energy region can be performed with high accuracy. Also, since the voltage waveform between the electrodes of the upper and lower electrodes is used, the above configuration can also be applied to a plasma processing apparatus in which a plurality of power supplies are connected to each electrode.

[0011] In one exemplary embodiment, the control device may control the impedance adjustment device to adjust the impedance of the lower electrode so as to reduce the peak value on the positive potential side of the voltage waveform.

[0012] In one exemplary embodiment, the impedance adjustment device may include a capacitor and an inductor. At least one of the capacitance of the capacitor and the inductance of the inductor is variable and can receive control by the control device. The capacitor and the inductor may be electrically connected in series. The capacitor may be electrically connected to the lower electrode. The inductor may be electrically connected to the lower electrode via the capacitor.

[0013] In one exemplary embodiment, the impedance adjusting device may include a first capacitor, a second capacitor, and an inductor. At least one of the capacitance of the first capacitor, the capacitance of the second capacitor, and the inductance of the inductor is variable and may be controlled by a control device. The first capacitor and the inductor may be electrically connected in series. The first capacitor may be electrically connected to the lower electrode. The inductor may be electrically connected to the lower electrode via the first capacitor. The second capacitor and the inductor may be electrically connected in parallel to the lower electrode via the first capacitor.

[0014] In one exemplary embodiment, the impedance adjusting device may include a plurality of electrical circuits electrically connected in parallel to the lower electrode. Each of the plurality of electrical circuits may include a capacitor and an inductor. In each of the plurality of electrical circuits, at least one of the capacitance of the capacitor and the inductance of the inductor is variable and may be controlled by a control device. In each of the plurality of electrical circuits, the capacitor and the inductor may be electrically connected in series. In each of the plurality of electrical circuits, the capacitor may be electrically connected to the lower electrode. In each of the plurality of electrical circuits, the inductor may be electrically connected to the lower electrode via the capacitor.

[0015] In one exemplary embodiment, the impedance adjustment device may have a plurality of electric circuits electrically connected in parallel to the lower electrode. Each of the plurality of electric circuits may have a first capacitor, a second capacitor, and an inductor. In each of the plurality of electric circuits, at least one of the capacitance of the first capacitor, the capacitance of the second capacitor, and the inductance of the inductor is variable and may be controlled by a control device. In each of the plurality of electric circuits, the first capacitor and the inductor may be electrically connected in series. In each of the plurality of electric circuits, the first capacitor may be electrically connected to the lower electrode. In each of the plurality of electric circuits, the inductor may be electrically connected to the lower electrode via the first capacitor. In each of the plurality of electric circuits, the second capacitor and the inductor may be electrically connected in parallel to the lower electrode via the first capacitor.

[0016] In one exemplary embodiment, each of the plurality of electric circuits may have capacitors with different capacitances from each other, and inductors with different inductances from each other.

[0017] In one exemplary embodiment, each of the plurality of electric circuits may have a first capacitor with different capacitances from each other, a second capacitor with different capacitances from each other, and an inductor with different inductances from each other.

[0018] Hereinafter, various exemplary embodiments will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts will be denoted by the same reference numerals. FIG. 1 is a diagram schematically showing a plasma processing apparatus according to one exemplary embodiment. The plasma processing apparatus 1 shown in FIG. 1 includes a chamber 10. The chamber 10 provides an internal space therein. The chamber 10 may include a chamber body 12. The chamber body 12 has a substantially cylindrical shape. The internal space of the chamber 10 is provided inside the chamber body 12. The chamber body 12 is formed of a metal such as aluminum. The chamber body 12 is electrically grounded. Note that the side wall of the chamber body 12 may provide a passage through which the substrate W passes when being transported. Further, a gate valve may be provided along the side wall of the chamber body 12 to open and close this passage.

[0019] The plasma processing apparatus 1 further includes a substrate support portion 14. The substrate support portion 14 is installed inside the chamber 10. The substrate support portion 14 is configured to support the substrate W placed thereon. The substrate support portion 14 has a main body. The main body of the substrate support portion 14 is formed of, for example, aluminum nitride and may have a disk shape. The substrate support portion 14 may be supported by a support member 16. The support member 16 extends upward from the bottom of the chamber 10. The substrate support portion 14 includes a lower electrode 18. The substrate support portion 14 may be provided in the chamber 10 (chamber body 12) so that the substrate W is placed thereon. The lower electrode 18 is included in the substrate support portion 14 and is embedded in the main body of the substrate support portion 14.

[0020] The plasma processing apparatus 1 further includes an upper electrode 20. The upper electrode 20 is provided in the chamber 10 and is provided above the substrate support portion 14. The upper electrode 20 is arranged to face the lower electrode 18. The upper electrode 20 constitutes the ceiling of the chamber 10. The upper electrode 20 is electrically separated from the chamber body 12. In one embodiment, the upper electrode 20 is fixed to the upper part of the chamber body 12 via an insulating member 21.

[0021] In one embodiment, the upper electrode 20 is configured as a shower head. The upper electrode 20 provides a gas diffusion space 20d therein. Further, the upper electrode 20 further provides a plurality of gas holes 20h. The plurality of gas holes 20h extend downward from the gas diffusion space 20d and open toward the internal space of the chamber 10. That is, the plurality of gas holes 20h connect the gas diffusion space 20d and the internal space of the chamber 10.

[0022] The plasma processing apparatus 1 further includes a gas supply unit 22. The gas supply unit 22 is configured to supply gas into the chamber 10. The gas supply unit 22 is configured to supply a processing gas between the upper electrode 20 and the lower electrode 18. The gas supply unit 22 is connected to the gas diffusion space 20d via a pipe 23. The gas supply unit 22 may have one or more gas sources, one or more flow controllers, and one or more on-off valves. Each of the one or more gas sources is connected to the pipe 23 via a corresponding flow controller and a corresponding on-off valve.

[0023] In one embodiment, the gas supply unit 22 may supply a film-forming gas. That is, the plasma processing apparatus 1 may be a film-forming apparatus. The film formed on the substrate W using the film-forming gas may be an insulating film. In another embodiment, the gas supply unit 22 may supply an etching gas. That is, the plasma processing apparatus 1 may be a plasma etching apparatus.

[0024] The plasma processing apparatus 1 further includes an exhaust device 24. The exhaust device 24 includes a pressure controller such as an automatic pressure control valve and a vacuum pump such as a turbo molecular pump or a dry pump. The exhaust device 24 is connected to the internal space of the chamber 10 via an exhaust pipe from an exhaust port 12e provided on the side wall of the chamber body 12.

[0025] The plasma processing apparatus 1 further includes a high-frequency power supply 26. The high-frequency power supply 26 is electrically connected to the upper electrode 20 via a matching unit 28. The high-frequency power supply 26 may be configured to include the matching unit 28. The high-frequency power supply 26 is configured to generate plasma of a processing gas supplied between the upper electrode 20 and the lower electrode 18 from the gas supply unit 22 by applying a high-frequency voltage to the upper electrode 20. In one embodiment, the high-frequency power supply 26 generates high-frequency power. The frequency of the high-frequency power may be any frequency. The frequency of the high-frequency power may be 13.56 MHz or less. The frequency of the high-frequency power may be 2 MHz or less. The frequency of the high-frequency power may be 20 kHz or more.

[0026] The high-frequency power supply 26 is connected to the upper electrode 20 via the matching unit 28. The high-frequency power from the high-frequency power supply 26 is supplied to the upper electrode 20 via the matching unit 28. The matching unit 28 has a matching circuit that matches the impedance of the load of the high-frequency power supply 26 with the output impedance of the high-frequency power supply 26.

[0027] In another embodiment, the high-frequency power supply 26 may be configured to periodically apply pulses of a DC voltage to the upper electrode 20. The frequency that defines the period during which the pulses of the DC voltage from the high-frequency power supply 26 are applied to the upper electrode 20 is, for example, 10 kHz or more and 10 MHz or less. Note that when the high-frequency power supply 26 is configured to periodically apply pulses of a DC voltage to the upper electrode 20, the plasma processing apparatus 1 may not include the matching unit 28.

[0028] The plasma processing apparatus 1 further includes a ring electrode 30. The ring electrode 30 has an annular shape. The ring electrode 30 may be divided into a plurality of electrodes arranged along the circumferential direction. The ring electrode 30 is provided around the substrate support 14 so as to surround the outer periphery of the substrate support 14. A gap is provided between the ring electrode 30 and the outer periphery of the substrate support 14, but this gap may not be provided. The ring electrode 30 is electrically grounded.

[0029] In one embodiment, the plasma processing apparatus 1 further includes a gas supply unit 32. The gas supply unit 32 supplies a purge gas so that the purge gas flows upward through the gap between the ring electrode 30 and the substrate support unit 14. The gas supply unit 32 supplies the purge gas into the chamber 10 through the gas introduction port 12p. In the illustrated example, the gas introduction port 12p is provided in the wall of the chamber body 12 below the substrate support unit 14. The purge gas supplied by the gas supply unit 32 may be an inert gas, for example, a noble gas.

[0030] When plasma processing is performed on the substrate W in the plasma processing apparatus 1, a processing gas is supplied from the gas supply unit 22 into the chamber 10. Then, a high-frequency power or a pulse of a DC voltage from the high-frequency power supply 26 is applied to the upper electrode 20. As a result, plasma is generated from the processing gas in the chamber 10. The substrate W on the substrate support unit 14 is processed by chemical species from the generated plasma. For example, the chemical species from the plasma form a film on the substrate W. Alternatively, the chemical species from the plasma etch the substrate W.

[0031] In one embodiment, the plasma processing apparatus 1 further includes a measuring instrument V1, a measuring instrument V2, a detector VM, and an impedance adjusting device IA. The measuring instrument V1 is configured to measure the potential waveform of the upper electrode 20. The measuring instrument V2 is configured to measure the potential waveform of the lower electrode 18. The detector VM is configured to detect a voltage waveform obtained by subtracting the second potential measured by the measuring instrument V2 from the first potential waveform measured by the measuring instrument V1. The impedance adjusting device IA is configured to adjust the impedance of the lower electrode 18.

[0032] In one embodiment, the plasma processing apparatus 1 further includes a control device CNT. The control device CNT is configured to control an impedance adjustment device IA so as to adjust the impedance of the lower electrode 18 based on the voltage waveform detected by the detector VM. The control device CNT controls the impedance adjustment device IA so as to adjust the impedance of the lower electrode 18 to reduce the peak value on the positive potential side among the voltage waveforms detected by the detector VM.

[0033] The configuration of the impedance adjustment device IA will be described with reference to FIGS. 2 and 3.

[0034] FIG. 2 shows the configuration of an impedance adjustment device IA according to an example. The impedance adjustment device IA shown in FIG. 2 has an electric circuit LC1. The electric circuit LC1 has a capacitor C1 and an inductor L1. At least one of the capacitance of the capacitor C1 and the inductance of the inductor L1 is variable and can be controlled by the control device CNT. The capacitor C1 and the inductor L1 are electrically connected in series. The capacitor C1 is electrically connected to the lower electrode 18. The inductor L1 is electrically connected to the lower electrode 18 via the capacitor C1.

[0035] According to the impedance adjustment device IA shown in FIG. 2, the substrate support portion 14 can be made to have a high impedance at the excitation frequency for generating plasma by resonance and at the DC component by the electric circuit LC1 in which the capacitor C1 and the inductor L1 are electrically connected in series. Since the electric circuit LC1 is an LC series resonance circuit, it has a low impedance at resonance. However, since the parasitic capacitance of the substrate support portion 14 is electrically connected in parallel to the electric circuit LC1, a high impedance is realized for the substrate support portion 14.

[0036] FIG. 3 shows the configuration of an impedance adjustment device IA according to an example. The impedance adjustment device IA shown in FIG. 3 has an electric circuit LC2. The electric circuit LC2 has a capacitor C21, a capacitor C22, and an inductor L2. At least one of the first capacitance of the capacitor C21, the second capacitance of the capacitor C22, and the inductance of the inductor L2 is variable and can be controlled by a control device CNT. The capacitor C21 and the inductor L2 are electrically connected in series. The capacitor C21 and the capacitor C22 are electrically connected in series. The capacitor C21 is electrically connected to the lower electrode 18. The inductor L2 is electrically connected to the lower electrode 18 via the capacitor C21. The capacitor C22 and the inductor L2 are electrically connected in parallel to the lower electrode 18 via the capacitor C21.

[0037] According to the impedance adjustment device IA shown in FIG. 3, the electric circuit LC2 in which the capacitor C22 and the inductor L2 are electrically connected in parallel can make the substrate support portion 14 have a high impedance at the DC component and near the excitation frequency. The capacitor C21 of the electric circuit LC2 is provided to cut the DC component. In some cases, an LC parallel resonance circuit (a circuit including only the inductor L2 and the capacitor C22) may be provided as the LC circuit of the impedance adjustment device IA. In this case, the substrate support portion 14 can have a high impedance near the excitation frequency at which plasma is generated due to the resonance phenomenon, but the substrate support portion 14 has a low impedance at the DC component. Therefore, by providing the capacitor C21 in front of the LC parallel resonance circuit (a circuit including only the inductor L2 and the capacitor C22) as in the electric circuit LC2, the substrate support portion 14 can be made to have a high impedance even at the DC component.

[0038] The impedance adjustment device IA may have a plurality of electric circuits LC1 shown in FIG. 2 in order to cope with high-frequency superposition or power-frequency superposition. In this case, the impedance adjustment device IA has a plurality of electric circuits LC1 electrically connected in parallel to the lower electrode 18. Each of the plurality of electric circuits LC1 includes a capacitor C1 and an inductor L1. In each of the plurality of electric circuits LC1, at least one of the capacitance of the capacitor C1 and the inductance of the inductor L1 is variable and can be controlled by the control device CNT. In each of the plurality of electric circuits LC1, the capacitor C1 and the inductor L1 are electrically connected in series. In each of the plurality of electric circuits LC1, the capacitor C1 is electrically connected to the lower electrode 18. In each of the plurality of electric circuits LC1, the inductor L1 is electrically connected to the lower electrode 18 via the capacitor C1. Each of the plurality of electric circuits LC1 may have a capacitor C1 with a different capacitance and an inductor L1 with a different inductance from each other.

[0039] For example, when the impedance adjustment device IA has two electric circuits LC1 electrically connected in parallel to each other, the substrate support portion 14 can be made to have a high impedance at two frequencies. For example, when the impedance adjustment device IA has three electric circuits LC1 electrically connected in parallel to each other, the substrate support portion 14 can be made to have a high impedance at three frequencies. When the impedance adjustment device IA has even more electric circuits LC1 electrically connected in parallel to each other, the substrate support portion 14 can be made to have a high impedance at even more frequencies.

[0040] The impedance adjustment device IA may have a plurality of electric circuits LC2 shown in FIG. 3 to cope with high-frequency superimposition or power-frequency superimposition. In this case, the impedance adjustment device IA has a plurality of electric circuits LC2 electrically connected in parallel to the lower electrode 18. Each of the plurality of electric circuits LC2 has a capacitor C21, a capacitor C22, and an inductor L2. In each of the plurality of electric circuits LC2, at least one of the capacitance of the capacitor C21, the capacitance of the capacitor C22, and the inductance of the inductor L2 is variable and can be controlled by the control device CNT. In each of the plurality of electric circuits LC2, the capacitor C21 and the inductor L2 are electrically connected in series. In the plurality of electric circuits LC2, the capacitor C21 and the capacitor C22 are electrically connected in series. In each of the plurality of electric circuits LC2, the capacitor C21 is electrically connected to the lower electrode 18. In each of the plurality of electric circuits LC2, the inductor L2 is electrically connected to the lower electrode 18 via the capacitor C21. In each of the plurality of electric circuits LC2, the capacitor C22 and the inductor L2 are electrically connected in parallel to the lower electrode 18 via the capacitor C21. Each of the plurality of electric circuits LC2 may have capacitors C21 with different capacitances from each other, capacitors C22 with different capacitances from each other, and inductors L2 with different inductances from each other.

[0041] For example, when the impedance adjustment device IA has two electric circuits LC2 electrically connected in parallel to each other, the substrate support portion 14 can be made to have a high impedance at two frequencies. For example, when the impedance adjustment device IA has three electric circuits LC2 electrically connected in parallel to each other, the substrate support portion 14 can be made to have a high impedance at three frequencies. When the impedance adjustment device IA has even more electric circuits LC2 electrically connected in parallel to each other, the substrate support portion 14 can be made to have a high impedance at even more frequencies.

[0042] As described above, for the impedance adjustment device IA, by using the LC circuits (electric circuit LC1, electric circuit LC2) shown in FIGS. 2 and 3 respectively, the impedance of the substrate support portion 14 near the excitation frequency for generating plasma by the resonance phenomenon can be adjusted. Generally, when the substrate support portion 14 including the lower electrode 18 has a high impedance, the plasma concentrates on the upper electrode 20 and the side wall of the chamber body 12, so the energy of the ions heading toward the substrate support portion 14 can be adjusted to be low. At this time, by electrically opening the lower electrode 18, the impedance of the lower electrode 18 can be made infinite, but due to the parasitic capacitance generated in the substrate support portion 14 including the lower electrode 18, the substrate support portion 14 is electrically coupled to GND. In this case, it may not be possible to obtain the desired effect of adjusting the energy of the ions heading toward the substrate support portion 14 to be low. Therefore, by making a part of the LC circuits (electric circuit LC1, electric circuit LC2) variable, it is possible to achieve effective impedance adjustment of the substrate support portion 14 including the parasitic capacitance of the substrate support portion 14. Further, in the case of the electric circuit LC2 shown in FIG. 3, by installing the capacitor C21 between the LC circuit and the lower electrode 18 so as to be electrically parallel to the parasitic capacitance of the substrate support portion 14, the DC bias can be cut. Note that the configuration of the impedance adjustment device IA is not limited to the configurations shown in FIGS. 2 and 3 respectively, and the impedance adjustment device IA may have other configurations as long as they can achieve the same effects.

[0043] According to the plasma processing apparatus 1 having the above-described configuration, the impedance of the lower electrode 18 is adjusted according to the voltage waveform obtained by subtracting the second potential waveform of the lower electrode 18 from the first potential waveform of the upper electrode 20. Thereby, the energy of the ions traveling toward the lower electrode 18 generated during plasma generation can be adjusted. The sheath voltage on the lower electrode 18 that provides energy to the ions increases and decreases in correlation with the voltage between the upper electrode 20 and the lower electrode 18. Therefore, optimization of the ion energy becomes possible as compared with the case where the impedance of the lower electrode 18 is adjusted based on the current flowing through the lower electrode 18. In particular, since it is possible to adjust the sheath voltage on the lower electrode 18 to be lower, the energy of the ions in a lower energy region can be adjusted with high accuracy. Further, since the voltage waveform between the electrodes of the upper electrode 20 and the lower electrode 18 is used, the above configuration can also be applied to a plasma processing apparatus in which a plurality of power supplies are connected to each electrode.

[0044] As described above, various exemplary embodiments have been described, but the present invention is not limited to the above-described exemplary embodiments, and various additions, omissions, substitutions, and changes may be made. Further, it is possible to form other embodiments by combining elements in different embodiments.

[0045] From the above description, it will be understood that the various embodiments of the present disclosure have been described herein for the purpose of illustration and that various changes can be made without departing from the scope and spirit of the present disclosure. Therefore, the various embodiments disclosed herein are not intended to be limiting, and the true scope and spirit are indicated by the appended claims.

Explanation of Reference Numerals

[0046] 1…Plasma processing apparatus, 10…Chamber, 12…Chamber body, 12e…Exhaust port, 12p…Gas introduction port, 14…Substrate support part, 16…Support member, 18…Lower electrode, 20…Upper electrode, 20d…Gas diffusion space, 20h…Gas hole, 21…Insulating member, 22…Gas supply part, 23…Pipe, 24…Exhaust device, 26…High-frequency power supply, 28…Matcher, 30…Ring electrode, 32…Gas supply part, C1…Capacitor, C21…Capacitor, C22…Capacitor, CNT…Control device, IA…Impedance adjustment device, L1…Inductor, L2…Inductor, LC1…Electric circuit, LC2…Electric circuit, V1…Measuring instrument, V2…Measuring instrument, VM…Detector, W…Substrate.

Claims

1. A chamber, a lower electrode included in a substrate support portion configured such that a substrate is placed in the chamber, an upper electrode provided in the chamber and arranged to face the lower electrode, a gas supply unit configured to supply a processing gas between the upper electrode and the lower electrode, a high-frequency power source electrically connected to the upper electrode and configured to generate plasma of the processing gas by applying a high-frequency voltage to the upper electrode, a first measuring instrument configured to measure the potential waveform of the upper electrode, a second measuring instrument configured to measure the potential waveform of the lower electrode, a detector configured to detect a voltage waveform obtained by subtracting the second potential measured by the second measuring instrument from the first potential waveform measured by the first measuring instrument, an impedance adjusting device configured to adjust the impedance of the lower electrode, a control device configured to control the impedance adjusting device so as to adjust the impedance of the lower electrode based on the voltage waveform detected by the detector, comprising a plasma processing apparatus.

2. The control device controls the impedance adjusting device to adjust the impedance of the lower electrode so as to reduce the peak value on the positive potential side of the voltage waveform. The plasma processing apparatus according to claim 1.

3. The impedance adjusting device has a capacitor and an inductor, at least one of the capacitance of the capacitor and the inductance of the inductor is variable and is under the control of the control device, the capacitor and the inductor are electrically connected in series, the capacitor is electrically connected to the lower electrode, the inductor is electrically connected to the lower electrode via the capacitor. The plasma processing apparatus according to claim 1 or 2.

4. The impedance adjusting device has a first capacitor, a second capacitor, and an inductor, at least one of the first capacitance of the first capacitor, the second capacitance of the second capacitor, and the inductance of the inductor is variable and is under the control of the control device, the first capacitor and the inductor are electrically connected in series, the first capacitor is electrically connected to the lower electrode, The inductor is electrically connected to the lower electrode via the first capacitor, The second capacitor and the inductor are electrically connected in parallel to the lower electrode via the first capacitor. The plasma processing apparatus according to claim 1 or 2.

5. The impedance adjusting device has a plurality of electric circuits electrically connected in parallel to the lower electrode, Each of the plurality of electric circuits includes a capacitor and an inductor, In each of the plurality of electric circuits, at least one of the capacitance of the capacitor and the inductance of the inductor is variable and is under the control of the control device, In each of the plurality of electric circuits, the capacitor and the inductor are electrically connected in series, In each of the plurality of electric circuits, the capacitor is electrically connected to the lower electrode, In each of the plurality of electric circuits, the inductor is electrically connected to the lower electrode via the capacitor. The plasma processing apparatus according to claim 1 or 2.

6. The impedance adjusting device has a plurality of electric circuits electrically connected in parallel to the lower electrode, Each of the plurality of electric circuits has a first capacitor, a second capacitor, and an inductor, In each of the plurality of electric circuits, at least one of the capacitance of the first capacitor, the capacitance of the second capacitor, and the inductance of the inductor is variable and is under the control of the control device, In each of the plurality of electric circuits, the first capacitor and the inductor are electrically connected in series, In each of the plurality of electric circuits, the first capacitor is electrically connected to the lower electrode, In each of the plurality of electric circuits, the inductor is electrically connected to the lower electrode via the first capacitor, In each of the plurality of electric circuits, the second capacitor and the inductor are electrically connected in parallel to the lower electrode via the first capacitor. The plasma processing apparatus according to claim 1 or 2.

7. Each of the plurality of electric circuits has capacitors with different capacitances and inductors with different inductances. The plasma processing apparatus according to claim 5.

8. Each of the plurality of electric circuits has the first capacitor having different capacitances from each other, the second capacitor having different capacitances from each other, and the inductor having different inductances from each other. The plasma processing apparatus according to claim 6.

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