Cleaning method and plasma processing apparatus

Abstract

The cleaning method is a method for cleaning a plasma processing apparatus, and includes the steps of supporting a substrate on a substrate support disposed in a chamber and having a first region for supporting the substrate and a second region for supporting an edge ring; adjusting the potential of the impedance adjustment electrode provided in the second region by controlling an impedance adjustment mechanism connected to the impedance adjustment electrode so that the potential of the second region is lower than the potential of the first region; supplying a cleaning gas into the chamber; supplying high-frequency power for generating plasma into the chamber to generate plasma from the cleaning gas; and supplying bias power into the chamber to clean components in the chamber.

Description

[Technical Field]

[0001] The present disclosure relates to a cleaning method and a plasma processing apparatus. [Background technology]

[0002] Patent Document 1 discloses "a cleaning method comprising the steps of removing residues of a group of typical semiconductor material elements from within a chamber using plasma of a halogen-containing gas, removing residues of a group 12 and 13 metal element group and a group 14 and 15 metal element group from within the chamber using plasma of a hydrocarbon-containing gas, and removing C-containing materials from within the chamber using plasma of an O-containing gas, wherein the steps of removing with plasma of a hydrocarbon-containing gas and removing with plasma of an O-containing gas are performed in this order a predetermined number of times X (X≧1) before or after the step of removing with plasma of a halogen-containing gas." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-12951 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a cleaning method and a plasma processing apparatus that can suppress wear on components inside a chamber while supplying a large bias power. [Means for solving the problem]

[0005] A cleaning method according to one embodiment of the present disclosure is a method for cleaning a plasma processing apparatus, and includes the steps of supporting a substrate on a substrate support disposed in a chamber and having a first region for supporting the substrate and a second region for supporting an edge ring; adjusting the potential of the impedance adjustment electrode provided in the second region by controlling an impedance adjustment mechanism connected to the impedance adjustment electrode so that the potential of the second region is lower than the potential of the first region; supplying a cleaning gas into the chamber; supplying high-frequency power for generating plasma into the chamber to generate plasma from the cleaning gas; and supplying bias power into the chamber to clean components in the chamber. [Effects of the Invention]

[0006] According to the present disclosure, it is possible to suppress wear on components inside the chamber while supplying a large bias power. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating an example of a plasma processing system according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic cross-sectional view showing an example of the configuration of a plasma processing apparatus according to this embodiment. [Figure 3] FIG. 3 is a diagram showing an example of the configuration of the electrodes in this embodiment. [Figure 4] FIG. 4 is a diagram showing an example of an equivalent circuit of the electrostatic chuck and plasma in this embodiment. [Figure 5] FIG. 5 is a diagram showing an example of the circuit configuration of the impedance adjustment mechanism in this embodiment. [Figure 6] FIG. 6 is a diagram showing an example of an image of the flow of an RF signal when the capacitance of the variable capacitor on the ring support surface side is reduced. [Figure 7] FIG. 7 is a diagram showing an example of an image of the flow of an RF signal when the capacitance of the variable capacitor on the ring support surface side is increased. [Figure 8] FIG. 8 is a diagram showing an example of the relationship between the capacitance of the variable capacitor on the ring support surface side and the potentials of the substrate and edge ring in this embodiment. [Figure 9] FIG. 9 is a diagram showing an example of an image of the flow of an RF signal when the capacitance of the variable capacitor on the substrate support surface side is increased. [Figure 10] FIG. 10 is a diagram showing an example of the relationship between the capacitance of the variable capacitor on the substrate support surface side and the potentials of the substrate and edge ring in this embodiment. [Figure 11] FIG. 11 is a flowchart showing an example of the cleaning process in this embodiment. [Figure 12] FIG. 12 is a flowchart showing an example of waferless cleaning processing in this embodiment. [Figure 13] FIG. 13 is a flowchart showing an example of the edge ring replacement process in this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the disclosed cleaning method and plasma processing apparatus will be described in detail with reference to the drawings. Note that the disclosed technology is not limited to the following embodiments.

[0009] In plasma processing equipment, deposits containing metals (e.g., aluminum, yttrium) may adhere to the chamber during plasma processing. These deposits are removed during cleaning. However, when attempting to remove metal-containing deposits adhering to the sidewalls of the chamber, for example, the plasma sheath is thinner over the grounded components, such as the sidewalls, making cleaning more difficult than over the substrate support, which is directly supplied with bias power. Therefore, to clean these grounded components, it is necessary to increase the ion energy of the plasma, i.e., to supply a large bias power. However, supplying a large bias power increases wear on components, such as an edge ring held by the substrate support. Therefore, it is desirable to suppress wear on the components within the chamber while supplying a large bias power.

[0010] [Configuration of plasma processing system] FIG. 1 illustrates an example of a plasma processing system according to an embodiment of the present disclosure. In this embodiment, the plasma processing system includes a plasma processing device 1 and a controller 2. The plasma processing system is an example of a substrate processing system, and the plasma processing device 1 is an example of a substrate processing device. The plasma processing device 1 includes a plasma processing chamber 10, a substrate support 11, and a plasma generation unit 12. The plasma processing chamber 10 has a plasma processing space. The plasma processing chamber 10 also has at least one gas supply port for supplying at least one processing gas to the plasma processing space and at least one gas exhaust port for exhausting gas from the plasma processing space. The gas supply port is connected to a gas supply unit 20 (described later), and the gas exhaust port is connected to an exhaust system 40 (described later). The substrate support 11 is disposed within the plasma processing space and has a substrate support surface for supporting a substrate.

[0011] The plasma generating unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma formed in the plasma processing space may be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR plasma), helicon wave plasma (HWP), or surface wave plasma (SWP). Various types of plasma generating units may be used, including alternating current (AC) plasma generating units and direct current (DC) plasma generating units. In one embodiment, the AC signal (AC power) used in the AC plasma generating unit has a frequency in the range of 100 kHz to 10 GHz. Therefore, the AC signal includes a radio frequency (RF) signal and a microwave signal. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0012] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform various processes described in this disclosure. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to perform various processes described herein. In one embodiment, 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 may be implemented by, for example, a computer 2a. The processing unit 2a1 may be configured to read a program from the storage unit 2a2 and execute the read program to perform various control operations. The program may be stored in the storage unit 2a2 in advance or may be acquired via a medium when needed. The acquired program is stored in the storage unit 2a2 and read from the storage unit 2a2 by the processing unit 2a1 for execution. The medium may be various storage media readable by the computer 2a or 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).

[0013] The following describes a configuration example of an inductively coupled plasma processing apparatus as an example of the plasma processing apparatus 1. Fig. 2 is a schematic cross-sectional view showing an example of the configuration of the plasma processing apparatus according to this embodiment.

[0014] The inductively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. The plasma processing chamber 10 includes a dielectric window 101. The plasma processing apparatus 1 also includes a substrate support 11, a gas inlet, and an antenna 14. The substrate support 11 is an example of a substrate support and is disposed within the plasma processing chamber 10. The antenna 14 is disposed on or above the plasma processing chamber 10 (i.e., on or above the dielectric window 101). The plasma processing chamber 10 has a plasma processing space 10s defined by the dielectric window 101, a sidewall 102 of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 is grounded.

[0015] 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 a substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of a substrate W. The annular region 111b of the main body 111 surrounds the central region 111a of the main body 111 in a planar 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 referred to as a substrate support surface for supporting the substrate W, and the annular region 111b is also referred to as a ring support surface for supporting the ring assembly 112. The central region 111a is an example of a first region, and the annular region 111b is an example of a second region. In the following description, the central region 111a may be referred to as a substrate support surface 111a, and the annular region 111b may be referred to as a ring support surface 111b.

[0016] 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 can function as part of an electrical path 38 connected to a first bias electrode 34 and a second bias electrode 35 (described later). A power supply line 33a is connected to the bottom of the base 1110. The power supply line 33a is also included in the electrical path 38. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode (not shown) 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. The annular region 111b may also be included in another member surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member. 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. At least one RF / DC electrode coupled to an RF power supply 31 and / or a DC power supply 32 (described later) may be disposed within the ceramic member 1111a. In this case, the at least one RF / DC electrode functions as a bias electrode. That is, a first bias electrode 34 and a second bias electrode 35 (described later) are electrically connected to the RF power supply 31 and / or the DC power supply 32 via an electrical path 38. Note that the conductive member of the base 1110 and the at least one RF / DC electrode may function as multiple bias electrodes. Alternatively, an electrostatic electrode (not shown) may function as a bias electrode, or the first bias electrode 34 may function as an electrostatic electrode. Therefore, the substrate support 11 includes at least one bias electrode.

[0017] 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.

[0018] 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 W to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow path 1110a, or a combination thereof. A heat transfer fluid such as brine or a gas flows through the flow path 1110a. In one embodiment, the flow path 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 backside of the substrate W and the central region 111a.

[0019] The electrostatic chuck 1111 includes a first impedance adjustment electrode 50 and a first bias electrode 34 located below the substrate support surface 111a, in that order from the substrate support surface 111a side. The electrostatic chuck 1111 is made of a dielectric material, such as ceramics. The electrostatic chuck 1111 also includes a second impedance adjustment electrode 51 and a second bias electrode 35 located below the ring support surface 111b, in that order from the ring support surface 111b side. The first bias electrode 34 is connected to, for example, the bottom of the base 1110 via a conductor 36b passing through a through-hole 36a in the base 1110. An insulating sleeve (not shown) is provided inside the through-hole 36a, electrically insulating the base 1110 from the conductor 36b within the through-hole 36a. The second bias electrode 35 is connected to, for example, the bottom of the base 1110 via a conductor 37b passing through a through-hole 37a in the base 1110. An insulating sleeve (not shown) is provided inside the through-hole 37a, and the base 1110 and the conductor 37b are electrically insulated from each other inside the through-hole 37a.

[0020] That is, the first bias electrode 34 and the second bias electrode 35 are connected to the matching circuit 33 (described later) via the conductors 36b and 37b, the base 1110, and the power supply line 33a, thereby forming an electrical path 38. Note that the connection between the first bias electrode 34 and the second bias electrode 35 and the base 1110 is not limited to a conductive member, and any method capable of supplying a bias RF signal, such as magnetic resonance, capacitive coupling, or inductive coupling, may be used. That is, the electrical path 38 is configured to connect a bias power supply (for example, a second RF generating unit 31b (described later)), the first bias electrode 34, and the second bias electrode 35. Alternatively, the electrical path 38 may be configured so that the second RF generating unit 31b (described later) is not connected to the base 1110, and the second RF generating unit 31b is directly connected to the first bias electrode 34 and the second bias electrode 35.

[0021] The first impedance adjustment electrode 50 is grounded via an impedance adjustment mechanism 52. The impedance adjustment mechanism 52 adjusts the amount of a portion of the RF signal (electrical bias) supplied from the first bias electrode 34 that flows to the ground (earth, ground). By adjusting the amount of the RF signal that flows to the ground using the first impedance adjustment electrode 50, the potential of the substrate W is adjusted, and this is used to control the tilt angle and / or adjust the etching rate. Furthermore, by adjusting the amount of the RF signal that flows to the ground using the first impedance adjustment electrode 50, wear on the substrate support surface 111a is suppressed during cleaning of the substrate support surface 111a and the ring assembly 112. At least one first impedance adjustment electrode 50 is provided within the electrostatic chuck 1111. Furthermore, the impedance adjustment mechanism 52 is connected to the first impedance adjustment electrode 50. When a plurality of first impedance adjustment electrodes 50 are provided, for example, two or more are provided in the circumferential direction of the substrate support part 11, and the number of impedance adjustment mechanisms 52 corresponds to the number of first impedance adjustment electrodes 50. Furthermore, two or more first impedance adjusting electrodes 50 may be provided in the radial direction of the substrate support part 11. Furthermore, two or more first impedance adjusting electrodes 50 may be provided in each of the circumferential direction and the radial direction of the substrate support part 11. The first impedance adjusting electrodes 50 are arranged so as to be parallel to the first bias electrode 34.

[0022] The second impedance adjustment electrode 51 is grounded via an impedance adjustment mechanism 53. The impedance adjustment mechanism 53 adjusts the amount of a portion of the RF signal (electrical bias) supplied from the second bias electrode 35 that flows to the ground (earth, ground). By adjusting the amount of the RF signal that flows to the ground using the second impedance adjustment electrode 51, the potential of the ring assembly 112 is adjusted, and this is used to control the tilt angle and / or adjust the etching rate. Furthermore, by adjusting the amount of the RF signal that flows to the ground using the second impedance adjustment electrode 51, wear on the ring assembly 112 can be suppressed even when bias power sufficient to clean the sidewall 102 of the plasma processing chamber 10 is supplied. At least one second impedance adjustment electrode 51 is provided within the electrostatic chuck 1111. When a plurality of second impedance adjustment electrodes 51 are provided, for example, two or more are provided in the circumferential direction of the substrate support 11, and the number of impedance adjustment mechanisms 53 provided corresponds to the number of second impedance adjustment electrodes 51. Furthermore, two or more second impedance adjustment electrodes 51 may be provided in the radial direction of the substrate support part 11. Furthermore, two or more second impedance adjustment electrodes 51 may be provided in each of the circumferential direction and the radial direction of the substrate support part 11. The second impedance adjustment electrodes 51 are arranged so as to be parallel to the second bias electrode 35.

[0023] By placing the first bias electrode 34 and the second bias electrode 35 as close as possible to the substrate W and the ring assembly 112, the impedance of the capacitor formed by the substrate W, the ring assembly 112, the ceramics of the electrostatic chuck 1111, and these electrodes is reduced. This reduces the potential difference between the first bias electrode 34 and the second bias electrode 35 and the substrate W and ring assembly 112. Similarly, the impedance of the capacitor formed by the first bias electrode 34 and the second bias electrode 35 and the first impedance adjustment electrode 50 and the second impedance adjustment electrode 51, respectively, is also reduced. Furthermore, the impedance of the capacitor formed by the first impedance adjustment electrode 50 and the second impedance adjustment electrode 51 and the substrate W and ring assembly 112, respectively, is also reduced.

[0024] At least one of the impedance adjustment mechanisms 52, 53 may be provided, or both may be provided. When one of the impedance adjustment mechanisms 52, 53 is not provided, the first impedance adjustment electrode 50 or the second impedance adjustment electrode 51 on the side where the impedance adjustment mechanism is not provided may be connected to earth (ground) via a predetermined impedance value. Alternatively, the first impedance adjustment electrode 50 or the second impedance adjustment electrode 51 on the side where the impedance adjustment mechanism is not provided may not be connected to earth and may be in a floating state.

[0025] The gas inlet is configured to introduce at least one process gas from the gas supply unit 20 into the plasma processing space 10s. In one embodiment, the gas inlet includes a center gas injector (CGI) 13. The center gas injector 13 is disposed above the substrate support 11 and attached to a central opening formed in the dielectric window 101. The center gas injector 13 has at least one gas supply port 13a, at least one gas flow path 13b, and at least one gas inlet port 13c. The process gas supplied to the gas supply port 13a passes through the gas flow path 13b and is introduced into the plasma processing space 10s from the gas inlet port 13c. Note that the gas inlet may include one or more side gas injectors (SGIs) attached to one or more openings formed in the sidewall 102 in addition to or instead of the center gas injector 13.

[0026] The gas supply unit 20 may include at least one gas source 21 and at least one flow rate controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one process gas from a corresponding gas source 21 to the gas inlet via a corresponding flow rate controller 22. Each flow rate controller 22 may include, for example, a mass flow controller or a pressure-controlled flow rate controller. Furthermore, the gas supply unit 20 may include at least one flow rate modulation device that modulates or pulses the flow rate of the at least one process gas. Note that the gas supply unit 20 is configured to supply a cleaning gas as a process gas in the cleaning process. Examples of cleaning gases include tetrafluoromethane gas, oxygen gas, and argon gas.

[0027] The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power) to at least one of the first bias electrode 34, the second bias electrode 35, and the antenna 14. This causes a plasma to be formed from at least one processing gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least a part of the plasma generation unit 12. Furthermore, by supplying a bias RF signal to at least one of the first bias electrode 34 and the second bias electrode 35, a bias potential is generated on the substrate W, thereby attracting ions in the formed plasma to the substrate W.

[0028] 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 the antenna 14 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 the antenna 14. Note that the first RF generating unit 31a is an example of a source power supply, and the source RF signal is an example of high-frequency power.

[0029] The second RF generating unit 31b is coupled to the first bias electrode 34 and the second bias electrode 35 via the matching circuit 33, the feed line 33a, and the base 1110, and is configured to generate a bias RF signal (bias RF power). The generated bias RF signal is supplied to the first bias electrode 34 and the second bias electrode 35. 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 of the first bias electrode 34 and the second bias electrode 35. In various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed. The second RF generating unit 31b is an example of a bias power supply, and the bias RF signal is an example of bias power.

[0030] The matching circuit 33 is connected to the second RF generating unit 31b and the substrate support 11 (base 1110). The matching circuit 33 enables a bias RF signal to be supplied from the second RF generating unit 31b to the substrate support 11 via the matching circuit 33. The matching circuit 33 also enables a bias DC signal to be supplied from a bias DC generating unit 32a (described later) to the substrate support 11 via the matching circuit 33.

[0031] 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 bias DC generator 32a. In one embodiment, the bias DC generator 32a is connected to at least one of a first bias electrode 34 and a second bias electrode 35 and configured to generate a bias DC signal. The generated bias DC signal is applied to at least one of the first bias electrode 34 and the second bias electrode 35. Note that the bias DC generator 32a is an example of a bias power supply, and the bias DC signal is an example of a bias power.

[0032] In various embodiments, the bias DC signal may be pulsed. In this case, a sequence of voltage pulses is applied to at least one of the first bias electrode 34 and the second bias electrode 35. The voltage pulses may have a rectangular, trapezoidal, triangular, or combination thereof. In one embodiment, a waveform generator for generating a sequence of voltage pulses from a DC signal is connected between the bias DC generator 32a and at least one of the first bias electrode 34 and the second bias electrode 35. Thus, the bias DC generator 32a and the waveform generator constitute a voltage pulse generator. The voltage pulses may have positive or negative polarity. The sequence of voltage pulses may include one or more positive voltage pulses and one or more negative voltage pulses within one cycle. The bias DC generator 32a may be provided in addition to the RF power supply 31 or instead of the second RF generator 31b. The bias RF signal and the bias DC signal (bias power) may be power capable of cleaning the sidewall 102 in the plasma processing chamber 10. Furthermore, the bias RF signal and bias DC signal may be powers capable of cleaning the substrate support surface 111a and the edge ring (ring assembly 112). The bias power may include one or more of a high frequency signal and a pulsed DC signal. Also, low frequency bias power is more effective.

[0033] The antenna 14 includes one or more coils. In one embodiment, the antenna 14 may include an outer coil and an inner coil arranged coaxially. In this case, the RF power supply 31 may be connected to both the outer coil and the inner coil, or to either the outer coil or the inner coil. In the former case, the same RF generator may be connected to both the outer coil and the inner coil, or separate RF generators may be connected to the outer coil and the inner coil separately.

[0034] 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 regulating valve regulates the pressure in the plasma processing space 10s. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0035] [Potential on the substrate support 11] Next, the potential on the substrate support 11 will be described with reference to FIG. 3. FIG. 3 is a diagram showing an example of the electrode configuration in this embodiment. In FIG. 3, a bias RF signal is supplied to the first bias electrode 34 and the second bias electrode 35 from the second RF generator 31b via the base 1110 and an electrical path 38 made of a conductive member. Also, a bias DC signal may be supplied to the first bias electrode 34 and the second bias electrode 35 from the bias DC generator 32a via the electrical path 38 instead of or together with the bias RF signal. The electrical path 38 is an example of a bias transmission line.

[0036] As shown in FIG. 3, on the substrate support surface 111a, a bias RF signal supplied from the first bias electrode 34 disposed below the substrate support surface 111a is split into an RF signal 60 and an RF signal 62. The RF signal 60 is an RF signal supplied to the plasma via the first impedance adjustment electrode 50 and the substrate W. The RF signal 62 is an RF signal that flows from the first impedance adjustment electrode 50 to the ground via the impedance adjustment mechanism 52. On the other hand, on the ring support surface 111b, a bias RF signal supplied from the second bias electrode 35 disposed below the ring support surface 111b is split into an RF signal 61 and an RF signal 63. The RF signal 61 is an RF signal that is supplied to the plasma via the second impedance adjustment electrode 51 and the ring assembly 112. The RF signal 63 is an RF signal that flows from the second impedance adjustment electrode 51 to the ground via the impedance adjustment mechanism 53.

[0037] At this time, assume that potential 64, which is a line representing a predetermined potential above the substrate W, and potential 65, which is a line representing a predetermined potential above the ring assembly 112, have different levels, as shown in FIG. 3 . In this case, for example, by adjusting the impedance adjustment mechanism 53, the level of potential 65 is adjusted within a range 66. As a result, in this embodiment, the tilt angle corresponding to the direction of the electric field 67 can be controlled by the ratio of potential 64 to potential 65. Furthermore, for example, by adjusting the impedance adjustment mechanisms 52 and 53, the etching rate of the outer periphery of the substrate W can be controlled, and the etching rate of the inner periphery of the substrate W can also be controlled. Furthermore, for example, by making the level of potential 65 lower than the level of potential 64, wear of the ring assembly 112 can be suppressed even when bias power capable of cleaning the sidewall 102 of the plasma processing chamber 10 is supplied.

[0038] Furthermore, when adjusting the impedance adjustment mechanism 52, the level of the potential 64 is adjusted within a range 68. As a result, in this embodiment, when controlling the etching rate of the outer periphery of the substrate W, it is possible to prevent the etching rate of the inner periphery of the substrate W from changing simultaneously. Furthermore, for example, by making the level of the potential 64 lower than the potential 65, it is possible to prevent wear of the substrate support surface 111a when cleaning the vicinity of the boundary between the substrate support surface 111a and the ring assembly 112 while the substrate W is not being held. Note that in FIG. 3, the angle of the electric field direction 67 is exaggerated for ease of explanation. Furthermore, in this embodiment, the first impedance adjustment electrode 50 and the second impedance adjustment electrode 51 are embedded in the electrostatic chuck 1111, which allows the structure of the plasma processing apparatus 1 to be made compact.

[0039] Next, an equivalent circuit of a circuit through which a bias RF signal flows will be described with reference to Fig. 4. Fig. 4 is a diagram showing an example of an equivalent circuit of an electrostatic chuck and plasma in this embodiment. In Fig. 4, the bias RF signal supplied to the first bias electrode 34 and the second bias electrode 35 is V RF Furthermore, the impedance between the first bias electrode 34 and the second bias electrode 35 and the first impedance adjustment electrode 50 and the second impedance adjustment electrode 51 is represented as Z1. Furthermore, the impedance between the first impedance adjustment electrode 50 and the second impedance adjustment electrode 51 and the substrate W and the ring assembly 112 is represented as Z2. Furthermore, the impedance of the impedance adjustment mechanisms 52, 53 between the first impedance adjustment electrode 50 and the second impedance adjustment electrode 51 and the ground (earth) is represented as Z3. Furthermore, the impedance of the plasma between the substrate W and the ring assembly 112 and the ground is represented as Z4.

[0040] Here, the voltage V3 applied to Z3 and the voltage V4 applied to Z4 are wafer can be expressed by the following formulas (1) and (2), respectively. In formulas (1) to (4), V RF is represented as V.

[0041]

number

number

[0042] Substituting equation (1) into equation (2), the voltage V applied to Z4 is wafer can be expressed by the following equation (3). Furthermore, dividing the fractional terms in equation (3) by Z4 and Z3, respectively, gives the following equation (4).

[0043]

number

number

[0044] The fractional term in equation (4) has the form f(x) = 1 / (x + 1), where f(x) is a function that approaches 1 as x decreases. Therefore, according to equation (4), the smaller Z2 is relative to Z4, the more efficiently the potential is transferred to the plasma. Furthermore, the smaller Z1 is relative to Z3, the more efficiently the potential is transferred to the plasma. To reduce Z2, it is preferable to position the first impedance adjustment electrode 50 and the second impedance adjustment electrode 51 as close as possible to the substrate W and the ring assembly 112. Similarly, to reduce Z1, it is preferable to position the first bias electrode 34 and the second bias electrode 35 as close as possible to the first impedance adjustment electrode 50 and the second impedance adjustment electrode 51. In this way, by positioning the first bias electrode 34 and the second bias electrode 35, the first impedance adjustment electrode 50 and the second impedance adjustment electrode 51, the substrate W, and the ring assembly 112 as close as possible, the sensitivity of potential control can be increased.

[0045] [Potential control based on equivalent circuits] 4, the potential control in the plasma processing apparatus 1 controls Z3 of the impedance adjustment mechanism 52 so that Z3 between the first impedance adjustment electrode 50 and the ground is larger than Z1 between the first bias electrode 34 and the first impedance adjustment electrode 50. In other words, the control unit 2 controls the potential of the first impedance adjustment electrode 50 by controlling Z3 of the impedance adjustment mechanism 52.

[0046] Furthermore, the potential control in the plasma processing apparatus 1 controls Z3 of the impedance adjustment mechanism 53 so that Z3 between the second impedance adjustment electrode 51 and the ground is larger than Z1 between the second bias electrode 35 and the second impedance adjustment electrode 51. In other words, the control unit 2 controls Z3 of the impedance adjustment mechanism 53 to control the potential of the second impedance adjustment electrode 51.

[0047] [Circuit configuration of impedance adjustment mechanism] Next, variations in the circuit configuration of the impedance adjustment mechanisms 52 and 53 will be described using FIG. 5. FIG. 5 is a diagram showing an example of the circuit configuration of the impedance adjustment mechanism in this embodiment. As shown in FIG. 5, the impedance adjustment mechanisms 52 and 53 can have various configurations, such as circuits 70 to 74. Circuit 70 is an LC series circuit using an inductor and a variable capacitor. Circuit 71 is an RC series circuit using a resistor and a variable capacitor. Circuit 72 is an RR series circuit using a resistor and a variable resistor. Circuit 73 is a circuit that can be switched between a high-frequency LC series circuit and a low-frequency RR series circuit by a switch SW. Circuit 74 is a circuit that can be switched between a high-efficiency LC series circuit (inductor L1, variable capacitor C1) and a low-efficiency LC series circuit (inductor L2, variable capacitor C2) by a switch SW. As shown in graph 75, circuit 74 has a wide adjustment range achieved by switching the switch SW. Although not illustrated in FIG. 5, the impedance adjusting mechanisms 52 and 53 may have a circuit configuration using a variable inductor.

[0048] As described above, the impedance adjustment mechanisms 52 and 53 can use variable resistors, variable capacitors, variable inductors, etc., regardless of the type of circuit constants (R, L, C) to be adjusted. The impedance adjustment mechanisms 52 and 53 may also combine one or more variable mechanisms (variable resistors, variable capacitors, variable inductors, etc.) depending on the frequency, component size, and adjustment range of the bias RF signal. Since the impedance adjustment mechanisms 52 and 53 do not require the passage of heater current, variable resistors or variable capacitors can be used. Furthermore, the impedance adjustment mechanisms 52 and 53 may be configured with at least one of a variable resistor, a variable capacitor, a variable inductor, and a DC power supply. For example, when the bias RF signal is high frequency, the aforementioned Z1 and Z2 have small values. Therefore, controlling the potential using a DC power supply allows for more effective potential control. Furthermore, the impedance adjustment mechanisms 52 and 53 may be configured with variable capacitors 54 and 55, as described below.

[0049] [Image of potential during cleaning process] Next, an image of the potential during the cleaning process of the sidewall 102 will be described with reference to FIGS. 6 to 8. In FIGS. 6 to 8, the impedance adjustment mechanism 52 connected to the first impedance adjustment electrode 50 is omitted, as it is set to a specific value. FIG. 6 is a diagram showing an example of the image of the flow of an RF signal when the capacitance of the variable capacitor on the ring support surface side is reduced. As shown in FIG. 6, for example, during the process, the capacitance of the variable capacitor 54 of the impedance adjustment mechanism 53 connected to the second impedance adjustment electrode 51 is controlled to be reduced within the variable range. In this case, of the bias RF signal supplied from the second bias electrode 35, the RF signal 61a supplied to the plasma flows more than the RF signal 63a flowing to the impedance adjustment mechanism 53. In this case, for example, the RF signal 61a flows at the same level as the RF signal 60 on the substrate W side. That is, in FIG. 6, bias power is less likely to escape to the impedance adjustment mechanism 53, and the potential on the ring assembly 112 (edge ​​ring) is increased, and the potential on the substrate W and the potential on the ring assembly 112 are controlled to be approximately the same. That is, the plasma sheath thickness above the substrate W is approximately the same as the plasma sheath thickness above the ring assembly 112. If a cleaning process is performed on the side wall 102 to which a large bias power is supplied in this state, the ring assembly 112 is likely to be sputtered, resulting in significant wear of the ring assembly 112.

[0050] FIG. 7 is a diagram illustrating an example of the flow of an RF signal when the capacitance of the variable capacitor on the ring support surface side is increased. As shown in FIG. 7, for example, when cleaning the sidewall 102 of the plasma processing chamber 10, the capacitance of the variable capacitor 54 of the impedance adjustment mechanism 53 connected to the second impedance adjustment electrode 51 is controlled to be larger than that during the process. In this case, of the bias RF signal supplied from the second bias electrode 35, the RF signal 63b flowing to the impedance adjustment mechanism 53 flows more than the RF signal 61b supplied to the plasma. In this case, for example, the RF signal 61b flows less than the RF signal 60 on the substrate W side. That is, in FIG. 7, bias power is easily lost to the impedance adjustment mechanism 53, and the potential on the ring assembly 112 (edge ​​ring) is lowered. Therefore, even when cleaning the sidewall 102 to which a large bias power is supplied, the ring assembly 112 is less susceptible to sputtering, thereby suppressing wear of the ring assembly 112. That is, in this embodiment, by changing the potential on the ring assembly 112, the sputtering rate of the ring assembly 112 can be reduced and wear can be suppressed without changing the sputtering rates of other components.

[0051] 8 is a diagram showing an example of the relationship between the capacitance of the variable capacitor on the ring support surface side and the potential of the substrate and edge ring in this embodiment. In graph 80 shown in FIG. 8, the vertical axis represents the potential [V] of the substrate W and ring assembly 112, and the horizontal axis represents the capacitance of the variable capacitor 54 of the impedance adjustment mechanism 53 as VC capacitance [pF]. Also, graph 80 shows the potential of the substrate W as graph 81 and the potential of the ring assembly 112 as graph 82 when the capacitance of the variable capacitor 54 of the impedance adjustment mechanism 53 is changed. Furthermore, graph 80 shows the capacitance 83 of the variable capacitor 54 during process execution and the capacitance 84 of the variable capacitor 54 during cleaning processing, each with a dotted line.

[0052] During a process, the variable capacitor 54 is controlled to have a capacitance of 83, and as shown in graphs 81 and 82, the potential of the ring assembly 112 is approximately the same as the potential of the substrate W. That is, during a process, the variable capacitor 54 is controlled so that the plasma sheath thicknesses on the substrate W and the ring assembly 112 are constant. On the other hand, during a cleaning process, the variable capacitor 54 is controlled to have a capacitance of 84, and as shown in graphs 81 and 82, the potential of the ring assembly 112 is lower than the potential of the substrate W. That is, by controlling the variable capacitor 54 to have a capacitance of 84, wear on the ring assembly 112 during the cleaning process can be suppressed. Note that the potential of the substrate W shown in graph 81 does not change even when the capacitance of the variable capacitor 54 is changed, because the impedance adjustment mechanism 52 is set to a specific value. The capacitance of the variable capacitor 54 may also be adjusted, for example, to a value between the capacitances 83 and 84, depending on the components in the plasma processing chamber 10 to be cleaned.

[0053] Next, an image of the potential during the cleaning process near the boundary between the substrate support surface 111a and the ring assembly 112 will be described with reference to FIGS. 9 and 10. The impedance adjustment mechanism 53 connected to the second impedance adjustment electrode 51 is omitted in FIGS. 9 and 10, as it is set to a specific value. FIG. 9 is a diagram showing an example of the image of the flow of an RF signal when the capacitance of the variable capacitor on the substrate support surface side is increased. FIG. 9 shows a waferless cleaning state in which a substrate W is not placed on the substrate support surface 111a in order to clean the vicinity of the boundary between the substrate support surface 111a and the ring assembly 112. For example, organic deposits (e.g., deposits containing carbon) may adhere to the vicinity of the boundary between the substrate support surface 111a and the ring assembly 112. Organic deposits can be cleaned with lower ion energy than metal-containing deposits that adhere to the sidewall 102.

[0054] 9, consider, for example, a cleaning process near the boundary between the substrate support surface 111a and the ring assembly 112. In this cleaning process, the capacitance of the variable capacitor 55 of the impedance adjustment mechanism 52 connected to the first impedance adjustment electrode 50 is controlled to be larger than that during process execution. In this case, of the bias RF signal supplied from the first bias electrode 34, the RF signal 62a flowing to the impedance adjustment mechanism 52 flows more than the RF signal 60a supplied to the plasma. In this case, for example, the RF signal 60a is less than the RF signal 61 on the ring assembly 112 side. That is, in FIG. 9, bias power is easily lost to the impedance adjustment mechanism 52, and the potential on the substrate support surface 111a becomes lower than the potential on the ring assembly 112. Therefore, wear on the substrate support surface 111a can be suppressed when cleaning the vicinity of the boundary between the substrate support surface 111a and the ring assembly 112.

[0055] 10 is a diagram showing an example of the relationship between the capacitance of the variable capacitor on the substrate support surface side and the potential of the substrate and edge ring in this embodiment. In graph 85 shown in FIG. 10, the vertical axis represents the potential [V] of the substrate support surface 111a and the ring assembly 112, and the horizontal axis represents the capacitance of the variable capacitor 55 of the impedance adjustment mechanism 52 as VC capacitance [pF]. Also in graph 85, graph 86 shows the potential of the ring assembly 112 and graph 87 shows the potential of the substrate support surface 111a when the capacitance of the variable capacitor 55 of the impedance adjustment mechanism 52 is changed. Furthermore, in graph 85, the capacitance 88 of the variable capacitor 55 during process execution and the capacitance 89 of the variable capacitor 55 during cleaning are each shown by dotted lines.

[0056] During a process, the variable capacitor 55 is controlled to have a capacitance of 88, and as shown in graphs 86 and 87, the potential of the substrate W (substantially equal to the potential of the substrate support surface 111a) becomes approximately the same as the potential of the ring assembly 112. That is, during a process, the variable capacitor 55 is controlled so that the plasma sheath thicknesses on the substrate W and the ring assembly 112 are constant. On the other hand, during a cleaning process, the variable capacitor 55 is controlled to have a capacitance of 89, and as shown in graphs 86 and 87, the potential of the substrate support surface 111a becomes lower than the potential of the ring assembly 112. That is, by controlling the variable capacitor 55 to have a capacitance of 89, wear on the substrate support surface 111a during the cleaning process can be suppressed. Note that the potential of the ring assembly 112 shown in graph 86 does not change even when the capacitance of the variable capacitor 55 is changed, because the impedance adjustment mechanism 53 is set to a specific value. The capacitance of variable capacitor 55 may be adjusted to a value between capacitance 88 and capacitance 89, for example, depending on the components in plasma processing chamber 10 to be cleaned.

[0057] [Cleaning method] Next, a method for cleaning the inside of the plasma processing chamber 10 in this embodiment will be described. Fig. 11 is a flowchart showing an example of the cleaning process in this embodiment. Note that Fig. 11 illustrates an example in which a substrate W for cleaning is loaded and, for example, the sidewall 102 of the plasma processing chamber 10 is cleaned.

[0058] The control unit 2 controls a gate valve (not shown) to open a loading / unloading port. When the loading / unloading port is open, the substrate W is loaded into the plasma processing space 10s of the plasma processing chamber 10 through the loading / unloading port and is held by suction on the substrate support member 11. That is, the control unit 2 controls the plasma processing apparatus 1 to load the substrate W into the plasma processing chamber 10 (step S1). Note that the control unit 2 may also be a control device for the entire substrate processing system (not shown), including the plasma processing apparatus 1 and a transfer device in a transfer chamber (not shown) adjacent to the plasma processing chamber 10. The control unit 2 controls the gate valve to close the loading / unloading port.

[0059] The control unit 2 controls the impedance adjustment mechanism 53 to adjust the capacitance of the variable capacitor 54 connected to the second impedance adjustment electrode 51 so that it is larger than that during process execution. That is, the control unit 2 controls the impedance adjustment mechanism 53 to adjust the capacitance of the variable capacitor 54 so that the potential of the second region (ring assembly 112) is lower than the potential of the first region (substrate W) (step S2).

[0060] The controller 2 controls the exhaust system 40 connected to the gas outlet 10e to reduce the pressure in the plasma processing chamber 10 to a predetermined pressure. The controller 2 controls the gas supply unit 20 to supply a cleaning gas (plasma generating gas) to the plasma processing chamber 10 through the multiple gas inlets 13c (step S3). The controller 2 controls the power supply 30 to ignite plasma with a predetermined power. That is, the controller 2 controls the power supply 30 to supply high-frequency power for plasma generation into the plasma processing chamber 10 to generate plasma from the cleaning gas (step S4). The controller 2 controls the power supply 30 to supply bias power into the plasma processing chamber 10 to clean components (e.g., the sidewall 102) in the plasma processing chamber 10 (step S5). The controller 2 may control the impedance adjustment mechanism 53 during cleaning to change the component to be cleaned. That is, the controller 2 may adjust the potential of the impedance adjustment electrode (second impedance adjustment electrode 51) depending on the component to be cleaned in the plasma processing chamber 10. In other words, steps S2 to S5 may be rearranged or combined as long as no contradictions are present.

[0061] After the cleaning has been performed for a predetermined period of time, the control unit 2 controls the power supply 30 to stop the RF signal and stop plasma generation. The control unit 2 also controls the gate valve to open the loading / unloading port. The control unit 2 controls the plasma processing apparatus 1 to lift the substrate W using a lifter (not shown). When the loading / unloading port is open, the substrate W is unloaded from the plasma processing chamber 10 by an arm (not shown) of the transfer chamber through the loading / unloading port. That is, the control unit 2 controls the plasma processing apparatus 1 to unload the substrate W from the plasma processing chamber 10 (step S6). In this manner, the control unit 2 adjusts the capacitance of the variable capacitor 54 so that the potential of the ring assembly 112 is lower than the potential of the substrate W before performing cleaning. This allows for the supply of a large bias power while suppressing wear on components within the chamber. That is, in this embodiment, the sidewall 102 of the plasma processing chamber 10 can be cleaned by supplying a large bias power while suppressing wear on the ring assembly 112 (edge ​​ring). Furthermore, in this embodiment, the replacement interval of components within the plasma processing chamber 10 can be extended. Furthermore, in this embodiment, the process of adjusting the capacitance of the variable capacitor 54 is added to the existing cleaning conditions, so the existing cleaning conditions can be reused. Also, compared to a method such as forming a protective film on a member that needs to be protected from wear, the cleaning throughput can be improved.

[0062] Fig. 12 is a flowchart showing an example of waferless cleaning processing in this embodiment. Fig. 12 illustrates an example in which, for example, cleaning is performed near the boundary between the first region (substrate support surface 111a) and the second region (ring assembly 112) without loading a substrate W for cleaning. In the following explanation, steps S3 to S5 of the waferless cleaning processing in Fig. 12 are the same as those in the cleaning processing in Fig. 11, and therefore will not be described again.

[0063] 12, the control unit 2 executes the following process instead of the processes of steps S1 and S2. The control unit 2 controls the impedance adjustment mechanism 52 to adjust the capacitance of the variable capacitor 55 connected to the first impedance adjustment electrode 50 so that it is larger than the capacitance during process execution. That is, the control unit 2 controls the impedance adjustment mechanism 52 to adjust the capacitance of the variable capacitor 55 so that the potential of the first region (substrate support surface 111a) is lower than the potential of the second region (ring assembly 112) (step S11). After adjusting the capacitance of the variable capacitor 55, the control unit 2 proceeds to step S3.

[0064] After step S5, when cleaning has been performed for a predetermined period of time, the control unit 2 controls the power supply 30 to stop the RF signal, thereby stopping plasma generation and terminating the waferless cleaning process. In steps S11, S3, and S5, the potential of the impedance adjustment electrode (first impedance adjustment electrode 50) may be adjusted depending on the component in the plasma processing chamber 10 to be cleaned. That is, steps S11, S3, and S5 may be reversed or combined as long as no contradictions are present. In this way, the control unit 2 adjusts the capacitance of the variable capacitor 55 before performing cleaning so that the potential of the first region (substrate support surface 111a) is lower than the potential of the second region (ring assembly 112). This reduces wear on the first region (substrate support surface 111a).

[0065] 13 is a flowchart showing an example of the edge ring replacement process in this embodiment. Note that in FIG. 13, the cleaning process and seasoning process when replacing the edge ring are described as an example.

[0066] 13, the control unit 2 controls the impedance adjustment mechanism 53 to adjust the capacitance of the variable capacitor 54 connected to the second impedance adjustment electrode 51 so that it is larger than that during process execution. That is, the control unit 2 controls the impedance adjustment mechanism 53 to adjust the capacitance of the variable capacitor 54 so that the potential of the second region (ring assembly 112) is lower than the potential of the first region (substrate support surface 111a) (step S21).

[0067] The control unit 2 executes a first cleaning process (step S22). That is, similar to steps S3 to S5 of the cleaning process of FIG. 11, the control unit 2 reduces the pressure in the plasma processing chamber 10 to a predetermined pressure by controlling the exhaust system 40 connected to the gas exhaust port 10e. The control unit 2 controls the gas supply unit 20 to supply a cleaning gas (plasma generating gas) to the plasma processing chamber 10 through the multiple gas inlets 13c. The control unit 2 controls the power supply 30 to ignite plasma with a predetermined power. That is, the control unit 2 controls the power supply 30 to supply high-frequency power for plasma generation into the plasma processing chamber 10 to generate plasma from the cleaning gas. The control unit 2 controls the power supply 30 to supply bias power into the plasma processing chamber 10 to clean components in the plasma processing chamber 10. That is, the first cleaning process is an example of a process for performing waferless cleaning of the substrate support 11. The first cleaning process is an example of a process for performing first plasma cleaning.

[0068] After the cleaning has been performed for a predetermined time, the control unit 2 controls the power supply 30 to stop the RF signal and stop the generation of plasma. The control unit 2 also controls the gate valve to open the loading / unloading port. The control unit 2 controls the plasma processing apparatus 1 so that a lifter (not shown) lifts the edge ring of the ring assembly 112. When the loading / unloading port is open, the edge ring is unloaded from the plasma processing chamber 10 by an arm of the transfer chamber (not shown) through the loading / unloading port. That is, the control unit 2 controls the plasma processing apparatus 1 to unload the edge ring from the plasma processing chamber 10 (step S23).

[0069] When the loading / unloading port is open, the substrate W is loaded into the plasma processing space 10s of the plasma processing chamber 10 through the loading / unloading port and is held by suction on the substrate support 11. That is, the control unit 2 controls the plasma processing apparatus 1 to load the substrate W into the plasma processing chamber 10 (step S24). The control unit 2 closes the loading / unloading port by controlling the gate valve.

[0070] The control unit 2 controls the impedance adjustment mechanism 52 to adjust the capacitance of the variable capacitor 55 connected to the first impedance adjustment electrode 50 so that it is larger than that during process execution. That is, the control unit 2 controls the impedance adjustment mechanism 52 to adjust the capacitance of the variable capacitor 55 so that the potential of the first region (substrate support surface 111a) is lower than the potential of the second region (ring support surface 111b) (step S25).

[0071] The controller 2 then executes a second cleaning process (step S26). That is, similar to steps S3 to S5 of the cleaning process of FIG. 11, the controller 2 controls the exhaust system 40 connected to the gas outlet 10e to reduce the pressure inside the plasma processing chamber 10 to a predetermined pressure. The controller 2 controls the gas supply unit 20 to supply a cleaning gas (plasma generating gas) to the plasma processing chamber 10 through the multiple gas inlets 13c. The controller 2 controls the power supply 30 to ignite plasma with a predetermined power. That is, the controller 2 controls the power supply 30 to supply high-frequency power for plasma generation into the plasma processing chamber 10 to generate plasma from the cleaning gas. The controller 2 controls the power supply 30 to supply bias power into the plasma processing chamber 10 to clean the second region (the ring support surface 111b). That is, the second cleaning process is an example of a process in which the second region (the ring support surface 111b) is cleaned while the substrate W to be cleaned is supported on the first region (the substrate support surface 111a). The second cleaning process is an example of a process in which a second plasma cleaning is performed.

[0072] After the cleaning has been performed for a predetermined time, the controller 2 controls the power supply 30 to stop the RF signal and stop the generation of plasma. The controller 2 also controls the gate valve to open the loading / unloading port. While the loading / unloading port is open, the unused edge ring is loaded into the plasma processing space 10s of the plasma processing chamber 10 through the loading / unloading port and is attracted and held by the substrate support 11. That is, the controller 2 controls the plasma processing apparatus 1 to load the unused edge ring of the ring assembly 112 into the plasma processing chamber 10 (step S27). The controller 2 controls the gate valve to close the loading / unloading port.

[0073] The control unit 2 controls the impedance adjustment mechanism 53 to adjust the capacitance of the variable capacitor 54 connected to the second impedance adjustment electrode 51 so that it is larger than that during process execution. That is, the control unit 2 controls the impedance adjustment mechanism 53 to adjust the capacitance of the variable capacitor 54 so that the potential of the second region (ring assembly 112) is lower than the potential of the first region (substrate W) (step S28).

[0074] The control unit 2 executes a seasoning process (step S29). Specifically, the control unit 2 reduces the pressure in the plasma processing chamber 10 to a predetermined pressure by controlling the exhaust system 40 connected to the gas exhaust port 10e. The control unit 2 controls the gas supply unit 20 to supply plasma generating gas to the plasma processing chamber 10 through the multiple gas inlets 13c. The control unit 2 controls the power supply 30 to ignite plasma with a predetermined power. Specifically, the control unit 2 controls the power supply 30 to supply high-frequency power for plasma generation into the plasma processing chamber 10 to generate plasma from the plasma generating gas. The control unit 2 performs a seasoning process using the generated plasma. The seasoning process is a process for stabilizing the temperature and the state of deposits in the plasma processing chamber 10 by performing a predetermined plasma process. In other words, the seasoning process is an example of a plasma process performed with the cleaning substrate W supported in the first region (substrate support surface 111a) and an unused edge ring of the ring assembly 112 supported in the second region (ring support surface 111b).

[0075] After the seasoning process has been performed for a predetermined time, the control unit 2 controls the power supply 30 to stop the RF signal and stop plasma generation. The control unit 2 also controls the gate valve to open the loading / unloading port. The control unit 2 controls the plasma processing apparatus 1 to lift the substrate W with a lifter (not shown). When the loading / unloading port is open, the substrate W is unloaded from the plasma processing chamber 10 by an arm of the transfer chamber (not shown) through the loading / unloading port. That is, the control unit 2 controls the plasma processing apparatus 1 to unload the substrate W from the plasma processing chamber 10 (step S30). After the seasoning process, the control unit 2 may load a substrate for quality control and perform a predetermined process on the substrate for quality control. This allows the control unit 2 to check whether the plasma processing chamber 10 is in a normal state.

[0076] In this way, the control unit 2 adjusts the capacitance of at least one of the variable capacitors 54, 55 before performing plasma processing during the first cleaning process, the second cleaning process, and the seasoning process, so that the edge ring can be replaced while suppressing wear on components inside the chamber.

[0077] In other words, regarding the above-described cleaning process, the controller 2 controls the plasma processing apparatus 1 so that the substrate W is supported on the substrate support 11 disposed in the plasma processing chamber 10 and including a first region for supporting the substrate W and a second region for supporting an edge ring (ring assembly 112). The controller 2 also controls the impedance adjustment mechanism 53 connected to the impedance adjustment electrode (second impedance adjustment electrode 51) provided in the second region, thereby adjusting the potential of the impedance adjustment electrode (second impedance adjustment electrode 51) so that the potential of the second region is lower than the potential of the first region. The controller 2 also controls the gas supply unit 20 to supply a cleaning gas into the plasma processing chamber 10. The controller 2 also controls the first RF generator 31a (source power source) to supply a source RF signal (high-frequency power) into the plasma processing chamber 10 to generate plasma from the cleaning gas. The control unit 2 also controls at least one of the second RF generating unit 31b and the bias DC generating unit 32a (bias power supply) to supply at least one of a bias RF signal and a bias DC signal (bias power) into the plasma processing chamber 10 to clean components (e.g., the sidewall 102) within the plasma processing chamber 10.

[0078] Furthermore, when waferless cleaning is performed near the boundary between the first region and the second region, the control unit 2 controls each unit as follows. The control unit 2 controls the impedance adjustment mechanism 52 connected to the impedance adjustment electrode (first impedance adjustment electrode 50) provided in the first region, thereby adjusting the potential of the impedance adjustment electrode (first impedance adjustment electrode 50) so that the potential of the first region is lower than the potential of the second region. The control unit 2 also controls the gas supply unit 20 to supply a cleaning gas into the plasma processing chamber 10. The control unit 2 also controls the first RF generation unit 31a (source power supply) to supply a source RF signal (high-frequency power) into the plasma processing chamber 10 to generate plasma from the cleaning gas. The control unit 2 also controls at least one of the second RF generating unit 31b and the bias DC generating unit 32a (bias power supply) to supply at least one of a bias RF signal and a bias DC signal (bias power) into the plasma processing chamber 10 to clean components within the plasma processing chamber 10 (e.g., near the boundary between the substrate support surface 111a and the ring assembly 112).

[0079] Furthermore, in the edge ring replacement process, the control unit 2 controls each unit as follows. When waferless cleaning of the first region is performed, the control unit 2 controls the impedance adjustment mechanism 53 connected to the impedance adjustment electrode (second impedance adjustment electrode 51) provided in the second region, thereby adjusting the potential of the impedance adjustment electrode (second impedance adjustment electrode 51) so that the potential of the second region is lower than the potential of the first region. When cleaning the ring support surface 111b, the control unit 2 controls the impedance adjustment mechanism 52 connected to the impedance adjustment electrode (first impedance adjustment electrode 50) provided in the first region, thereby adjusting the potential of the impedance adjustment electrode (first impedance adjustment electrode 50) so that the potential of the first region is lower than the potential of the second region. When seasoning is performed, the control unit 2 controls the impedance adjustment mechanism 53 connected to the impedance adjustment electrode (second impedance adjustment electrode 51) provided in the second region, thereby adjusting the potential of the impedance adjustment electrode (second impedance adjustment electrode 51) so that the potential of the second region is lower than the potential of the first region.

[0080] In the above embodiment, the first impedance adjustment electrode 50 and the second impedance adjustment electrode 51 are provided below the substrate support surface 111a and the ring support surface 111b, respectively, but this is not limiting. For example, either the first impedance adjustment electrode 50 or the second impedance adjustment electrode 51 may be provided.

[0081] As described above, according to this embodiment, the cleaning method for the plasma processing apparatus 1 includes the steps of supporting the substrate W on a substrate support (substrate support unit 11) disposed in a chamber (plasma processing chamber 10) and including a first region (substrate support surface 111a) for supporting the substrate W and a second region (ring support surface 111b) for supporting an edge ring (ring assembly 112), adjusting the potential of an impedance adjustment electrode (second impedance adjustment electrode 51) provided in the second region by controlling an impedance adjustment mechanism (variable capacitor 54) connected to the impedance adjustment electrode so that the potential of the second region is lower than the potential of the first region, supplying a cleaning gas into the chamber, supplying high-frequency power for plasma generation into the chamber to generate plasma from the cleaning gas, and supplying bias power into the chamber to clean components within the chamber. As a result, wear of components within the chamber, such as the edge ring, can be suppressed while supplying a large bias power.

[0082] Furthermore, according to this embodiment, the bias power is a power that can clean the sidewall 102 inside the chamber, and as a result, metal-containing deposits adhering to the sidewall 102 can be removed.

[0083] Furthermore, according to this embodiment, the cleaning step adjusts the potential of at least one of the first impedance adjusting electrode 50 and the second impedance adjusting electrode 51 depending on the member to be cleaned inside the chamber, thereby enabling the member to be cleaned.

[0084] Furthermore, according to this embodiment, the bias power includes one or more of a high frequency signal and a pulsed DC signal, which makes it possible to supply a large bias power while suppressing wear on components within the chamber, regardless of the waveform of the bias power supply.

[0085] Furthermore, according to this embodiment, the impedance adjustment mechanism is composed of at least one of a variable resistor, a variable capacitor (variable capacitors 54 and 55), and a variable inductor, thereby making it possible to adjust the potential of the impedance adjustment electrode.

[0086] According to the present embodiment, a cleaning method for the plasma processing apparatus 1 includes the steps of: controlling an impedance adjustment mechanism (variable capacitor 55) connected to an impedance adjustment electrode (first impedance adjustment electrode 50) provided in a first region of a substrate support (substrate support unit 11) disposed in a chamber (plasma processing chamber 10) and including a first region (substrate support surface 111a) for supporting a substrate W and a second region (ring support surface 111b) for supporting an edge ring (ring assembly 112) to adjust the potential of the impedance adjustment electrode so that the potential of the first region is lower than the potential of the second region; supplying a cleaning gas into the chamber; supplying high-frequency power for plasma generation into the chamber to generate plasma from the cleaning gas; and supplying bias power into the chamber to clean components in the chamber. As a result, wear of the substrate support surface 111a can be suppressed when cleaning the vicinity of the boundary between the substrate support surface 111a and the ring assembly 112 (waferless cleaning).

[0087] According to the present embodiment, a cleaning method for the plasma processing apparatus 1 includes the steps of: controlling an impedance adjustment mechanism (variable capacitor 54) connected to an impedance adjustment electrode (second impedance adjustment electrode 51) provided in a second region of a substrate support (substrate support unit 11) disposed in a chamber (plasma processing chamber 10) and including a first region (substrate support surface 111a) for supporting a substrate W and a second region (ring support surface 111b) for supporting an edge ring (ring assembly 112); adjusting the potential of the impedance adjustment electrode so that the potential of the second region is lower than the potential of the first region; supplying a cleaning gas into the chamber; supplying high-frequency power for plasma generation into the chamber to generate plasma from the cleaning gas; and supplying bias power into the chamber to clean components in the chamber. As a result, edge ring wear can be suppressed while supplying a large bias power during cleaning in the edge ring replacement process.

[0088] Furthermore, according to this embodiment, the cleaning method further includes the steps of unloading the edge ring from the chamber, supporting the substrate W in the first region, and controlling an impedance adjustment mechanism (variable capacitor 55) connected to an impedance adjustment electrode (first impedance adjustment electrode 50) provided in the first region to adjust the potential of the impedance adjustment electrode so that the potential of the first region is lower than the potential of the second region. As a result, the ring support surface 111b can be cleaned in the edge ring replacement process.

[0089] Furthermore, according to this embodiment, the cleaning method further includes the steps of supporting the edge ring in the second region and controlling an impedance adjustment mechanism (variable capacitor 54) connected to an impedance adjustment electrode (second impedance adjustment electrode 51) provided in the second region to adjust the potential of the impedance adjustment electrode so that the potential of the second region is lower than the potential of the first region. As a result, in the edge ring replacement process, a seasoning process can be performed on the plasma processing chamber 10 including the replaced edge ring.

[0090] Furthermore, according to this embodiment, the bias power is a power that can clean the first region, thereby suppressing wear on other members within the plasma processing chamber 10.

[0091] According to this embodiment, the plasma processing apparatus 1 includes a chamber (plasma processing chamber 10), a plasma generating unit (RF power supply 31), a substrate support unit 11, a bias power supply (DC power supply 32), an impedance adjusting electrode, an impedance adjusting mechanism, and a control unit 2. The plasma generating unit is configured to generate plasma in the chamber. The substrate support unit 11 is disposed in the chamber and includes a base 1110, an electrostatic chuck 1111, a first bias electrode 34, a second bias electrode 35, and an edge ring (ring assembly 112). The electrostatic chuck 1111 is disposed on the base 1110 and includes a first region having a substrate support surface 111a and a second region disposed outside the first region and having a ring support surface 111b. The first bias electrode 34 is disposed in the first region. The second bias electrode 35 is disposed in the second region. The edge ring is disposed on the ring support surface 111b. The bias power supply is electrically connected to the first bias electrode 34 and the second bias electrode 35 via a bias transmission line and configured to supply a bias signal to the first bias electrode 34 and the second bias electrode 35. An impedance adjustment electrode (e.g., a first impedance adjustment electrode 50, a second impedance adjustment electrode 51) is provided in at least one of the first region and the second region. An impedance adjustment mechanism (e.g., an impedance adjustment mechanism 52, 53) is connected to the impedance adjustment electrode. The impedance adjustment electrode is also grounded via the impedance adjustment mechanism. The control unit 2 is configured to (a) plasma-process the substrate on the substrate support unit 11 in the chamber, and (b) plasma-clean the chamber by controlling the impedance adjustment mechanism so that the potential of the first region or the second region where the chamber internal component to be cleaned is located is higher than the potential in (a). As a result, wear of the components in the chamber can be suppressed while supplying a large bias power.

[0092] Furthermore, according to this embodiment, the impedance adjustment electrode (first impedance adjustment electrode 50) is provided in at least the first region so as to be parallel to the first bias electrode 34. (b) also includes a first plasma cleaning performed with the substrate W supported on the substrate support part 11. In the first plasma cleaning, the control part 2 controls the impedance adjustment mechanism 52 so that the potential of the first region is lower than the potential of the second region. As a result, the potential on the substrate support surface 111a side can be controlled. Furthermore, the edge ring can be cleaned.

[0093] Furthermore, according to this embodiment, the impedance adjustment electrode (second impedance adjustment electrode 51) is provided in at least the second region so as to be parallel to the second bias electrode 35. Also, (b) includes a second plasma cleaning performed in a state where the substrate W is not supported on the substrate support part 11. In the second plasma cleaning, the control part 2 controls the impedance adjustment mechanism 53 so that the potential of the second region is lower than the potential of the first region. As a result, the potential on the edge ring (ring assembly 112) side can be controlled.

[0094] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive, and various omissions, substitutions, and modifications may be made to the above-described embodiments without departing from the scope and spirit of the appended claims.

[0095] The present disclosure can also be configured as follows. (1) A method for cleaning a plasma processing apparatus, comprising: supporting the substrate on a substrate support disposed within the chamber, the substrate support having a first region for supporting the substrate and a second region for supporting an edge ring; adjusting the potential of the impedance adjustment electrode provided in the second region by controlling an impedance adjustment mechanism connected to the impedance adjustment electrode so that the potential of the second region is lower than the potential of the first region; supplying a cleaning gas into the chamber; supplying high frequency power for plasma generation into the chamber to generate plasma from the cleaning gas; providing a bias power into the chamber to clean components within the chamber; A cleaning method comprising: (2) the bias power is a power capable of cleaning a sidewall inside the chamber; The cleaning method according to (1) above. (3) the cleaning step adjusts the potential of the impedance adjusting electrode depending on the member to be cleaned in the chamber. The cleaning method according to (1) or (2) above. (4) The bias power includes one or more of a high frequency signal and a pulsed DC signal. The cleaning method according to any one of (1) to (3) above. (5) the impedance adjustment mechanism is configured by at least one of a variable resistor, a variable capacitor, and a variable inductor; The cleaning method according to any one of (1) to (4) above. (6) A method for cleaning a plasma processing apparatus, comprising: a substrate support disposed in a chamber and including a first region for supporting a substrate and a second region for supporting an edge ring, wherein the substrate support includes an impedance adjustment mechanism connected to the impedance adjustment electrode provided in the first region, thereby adjusting the potential of the impedance adjustment electrode so that the potential of the first region is lower than the potential of the second region; supplying a cleaning gas into the chamber; supplying high frequency power for plasma generation into the chamber to generate plasma from the cleaning gas; providing a bias power into the chamber to clean components within the chamber; A cleaning method comprising: (7) A method for cleaning a plasma processing apparatus, comprising: a substrate support disposed in a chamber and including a first region for supporting a substrate and a second region for supporting an edge ring, wherein the substrate support includes an impedance adjustment mechanism connected to the impedance adjustment electrode provided in the second region, thereby adjusting the potential of the impedance adjustment electrode so that the potential of the second region is lower than the potential of the first region; supplying a cleaning gas into the chamber; supplying high frequency power for plasma generation into the chamber to generate plasma from the cleaning gas; providing a bias power into the chamber to clean components within the chamber; A cleaning method comprising: (8) removing the edge ring from the chamber; supporting the substrate in the first region; and adjusting the potential of the impedance adjustment electrode provided in the first region by controlling an impedance adjustment mechanism connected to the impedance adjustment electrode so that the potential of the first region is lower than the potential of the second region. The cleaning method according to (7) above. (9) supporting an edge ring in the second region; and adjusting the potential of the impedance adjustment electrode provided in the second region by controlling an impedance adjustment mechanism connected to the impedance adjustment electrode so that the potential of the second region is lower than the potential of the first region. The cleaning method according to (8) above. (10) the bias power is a power capable of cleaning the first region; The cleaning method according to any one of (7) to (9) above. (11) the cleaning step adjusts the potential of the impedance adjusting electrode depending on the member to be cleaned in the chamber. The cleaning method according to any one of (7) to (10) above. (12) The bias power includes one or more of a high frequency signal and a pulsed DC signal. The cleaning method according to any one of (7) to (11) above. (13) the impedance adjustment mechanism is configured by at least one of a variable resistor, a variable capacitor, and a variable inductor; The cleaning method according to any one of (7) to (12) above. (14) a chamber; a plasma generating unit configured to generate plasma within the chamber; a substrate support disposed within the chamber, the substrate support comprising: The base and an electrostatic chuck disposed on the base, the electrostatic chuck including a first region having a substrate support surface and a second region disposed outside the first region and having a ring support surface; a first bias electrode disposed in the first region; a second bias electrode disposed in the second region; an edge ring disposed on the ring support surface; and a bias power supply electrically connected to the first bias electrode and the second bias electrode via a bias transmission line and configured to supply a bias signal to the first bias electrode and the second bias electrode; an impedance adjusting electrode provided in at least one of the first region and the second region; an impedance adjustment mechanism connected to the impedance adjustment electrode; A control unit; Equipped with the impedance adjustment electrode is grounded via the impedance adjustment mechanism; The control unit (a) plasma processing a substrate on the substrate support in the chamber; (b) controlling the impedance adjustment mechanism to plasma clean the inside of the chamber so that the potential of the first region or the second region where the chamber internal member to be cleaned is located becomes higher than the potential in (a); configured to perform Plasma processing equipment. (15) the impedance adjusting electrode is provided in at least the first region so as to be parallel to the first bias electrode, (b) includes a first plasma cleaning performed with the substrate supported on the substrate support; The control unit In the first plasma cleaning, the impedance adjustment mechanism is controlled so that the potential of the first region is lower than the potential of the second region. The plasma processing apparatus according to (14) above. (16) the impedance adjustment electrode is provided in at least the second region so as to be parallel to the second bias electrode, (b) includes a second plasma cleaning performed in a state where the substrate is not supported on the substrate support; The control unit In the second plasma cleaning, the impedance adjustment mechanism is controlled so that the potential of the second region is lower than the potential of the first region. The plasma processing apparatus according to (14) or (15) above. (17) the impedance adjustment mechanism is configured by at least one of a variable resistor, a variable capacitor, and a variable inductor; The plasma processing apparatus according to any one of (14) to (16) above. (18) the bias signal includes one or more of a high frequency signal and a pulsed DC signal; The plasma processing apparatus according to any one of (14) to (17) above. [Explanation of symbols]

[0096] 1. Plasma processing equipment 2. Control Unit 10 Plasma Processing Chamber 11 Substrate support 20 Gas supply unit 31 RF power supply 31a First RF generation unit 31b Second RF generation unit 32 DC power supply 32a Bias DC generator 33 Matching circuit 34 First bias electrode 35 Second bias electrode 38 Electrical Path 50 first impedance adjusting electrode 51 second impedance adjusting electrode 52,53 Impedance adjustment mechanism 54,55 Variable capacitor 102 Side wall 111a Central area (board support surface) 111b Annular region (ring support surface) 112 Ring Assembly 1110 Foundation 1111 Electrostatic chuck W substrate

Claims

1. A method for cleaning a plasma processing device, A step of supporting a substrate in a substrate support, which is arranged in a chamber and comprises a first region for supporting the substrate and a second region for supporting the edge ring, A step of adjusting the potential of the impedance adjusting electrode by controlling an impedance adjusting mechanism connected to an impedance adjusting electrode provided in the second region, such that the potential of the second region becomes lower than the potential of the first region. The steps include supplying cleaning gas into the chamber, A step of generating plasma from the cleaning gas by supplying high-frequency power for plasma generation into the chamber, A step of supplying bias power into the chamber to clean the components inside the chamber, A cleaning method having

2. The bias power is sufficient to clean the side walls inside the chamber. The cleaning method according to claim 1.

3. The cleaning step involves adjusting the potential of the impedance adjustment electrode according to the component in the chamber to be cleaned. The cleaning method according to claim 1.

4. The bias power includes one or more of the high-frequency signal and pulsed DC signal. The cleaning method according to claim 1.

5. The impedance adjustment mechanism is composed of at least one of a variable resistor, a variable capacitor, and a variable inductor. The cleaning method according to claim 1.

6. A method for cleaning a plasma processing device, A substrate support comprising a chamber and comprising a first region for supporting a substrate and a second region for supporting an edge ring, wherein the potential of the impedance adjustment electrode is adjusted by controlling an impedance adjustment mechanism connected to an impedance adjustment electrode provided at least within the first region so as to be parallel to a first bias electrode provided in the first region, so as to adjust the potential of the impedance adjustment electrode so that the potential of the first region is lower than the potential of the second region. The steps include supplying cleaning gas into the chamber, A step of generating plasma from the cleaning gas by supplying high-frequency power for plasma generation into the chamber, A step of supplying bias power into the chamber to clean the components inside the chamber, A cleaning method having

7. A method for cleaning a plasma processing device, A substrate support comprising a first region for supporting a substrate and a second region for supporting an edge ring, arranged within a chamber, comprising the steps of adjusting the potential of an impedance adjustment electrode by controlling an impedance adjustment mechanism connected to an impedance adjustment electrode provided in the second region, so that the potential of the second region becomes lower than the potential of the first region; The steps include supplying cleaning gas into the chamber, A step of generating plasma from the cleaning gas by supplying high-frequency power for plasma generation into the chamber, A step of supplying bias power into the chamber to clean the components inside the chamber, A cleaning method having

8. The process of removing the edge ring from inside the chamber, The steps include supporting the substrate in the first region, The method further comprises the step of adjusting the potential of an impedance adjusting electrode, which is connected to an impedance adjusting electrode provided within the first region, so that the potential of the first region becomes lower than the potential of the second region. The cleaning method according to claim 7.

9. The process of supporting the edge ring in the second region, The invention further comprises the step of adjusting the potential of an impedance adjusting electrode, which is connected to an impedance adjusting electrode provided within the second region, so that the potential of the second region becomes lower than the potential of the first region. The cleaning method according to claim 8.

10. The bias power is power capable of cleaning the first region. The cleaning method according to claim 7.

11. The cleaning step involves adjusting the potential of the impedance adjustment electrode according to the component in the chamber to be cleaned. The cleaning method according to claim 7.

12. The bias power includes one or more of the high-frequency signal and pulsed DC signal. The cleaning method according to claim 7.

13. The impedance adjustment mechanism is composed of at least one of a variable resistor, a variable capacitor, and a variable inductor. The cleaning method according to claim 7.

14. Chamber and, A plasma generation unit configured to generate plasma within the chamber, A substrate support portion is disposed within the chamber, and the substrate support portion is, Base and, An electrostatic chuck disposed on the base, wherein the electrostatic chuck includes a first region having a substrate support surface and a second region located outside the first region and having a ring support surface. A first bias electrode positioned in the first region, A second bias electrode positioned in the second region, A substrate support portion including an edge ring disposed on the ring support surface, A bias power supply is electrically connected to the first bias electrode and the second bias electrode via a bias transmission line and configured to supply bias signals to the first bias electrode and the second bias electrode, An impedance adjusting electrode provided in at least one of the first region and the second region, An impedance adjustment mechanism connected to the impedance adjustment electrode, Control unit and Equipped with, The impedance adjustment electrode is grounded via the impedance adjustment mechanism. The control unit, (a) Plasma treatment of the substrate on the substrate support portion in the chamber, (b) Plasma cleaning of the chamber by controlling the impedance adjustment mechanism so that the potential of the region in the chamber where the chamber member to be cleaned is located, among the first region or the second region, is higher than the potential in (a), Configured to perform, Plasma processing equipment.

15. The impedance adjusting electrode is provided at least within the first region so as to be parallel to the first bias electrode. (b) above includes a first plasma cleaning performed with the substrate supported on the substrate support portion, The control unit, In the first plasma cleaning, the impedance adjustment mechanism is controlled so that the potential of the first region is lower than the potential of the second region. The plasma processing apparatus according to claim 14.

16. The impedance adjusting electrode is provided at least within the second region so as to be parallel to the second bias electrode. (b) above includes a second plasma cleaning performed without supporting a substrate on the substrate support portion, The control unit, In the second plasma cleaning, the impedance adjustment mechanism is controlled so that the potential of the second region is lower than the potential of the first region. The plasma processing apparatus according to claim 14 or 15.

17. The impedance adjustment mechanism is composed of at least one of a variable resistor, a variable capacitor, and a variable inductor. The plasma processing apparatus according to claim 14 or 15.

18. The bias signal includes one or more of a high-frequency signal and a pulsed DC signal. The plasma processing apparatus according to claim 14 or 15.

Images