Plasma processing device

Abstract

A plasma processing device according to the present disclosure comprises a chamber, a plasma generation unit, a substrate support part, an edge ring, a lift mechanism, and a gas flow generator. The lift mechanism includes an electroconductive ring and an actuator. The electroconductive ring is disposed so as to surround an electrostatic chuck. The actuator is configured to cause the electroconductive ring, in a state in which the edge ring is supported on the electroconductive ring, to vertically move together with the edge ring. The electroconductive ring provides a gas flow path and one or more gas holes. The one or more gas holes are connected to the gas flow generator via the gas flow path. The one or more gas holes include at least one gas hole. The at least one gas hole opens toward a gap between the electroconductive ring and the electrostatic chuck.

Description

Plasma processing equipment

[0001] An exemplary embodiment of the present disclosure relates to a plasma processing apparatus.

[0002] An edge ring is placed on a substrate support disposed in a chamber of a plasma processing apparatus. The substrate support of the plasma processing apparatus disclosed in Patent Document 1 below includes an electrostatic chuck, a tuning ring on which the edge ring is placed, and an actuator mechanism configured to move the tuning ring.

[0003] Japanese Patent Application Laid-Open No. 2019-208023

[0004] The present disclosure provides a technique for suppressing particle generation.

[0005] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a plasma generating unit, a substrate support, an edge ring, a lift mechanism, and a gas flow generator. The substrate support is disposed within the chamber. The substrate support includes a base and an electrostatic chuck on the base. The edge ring is disposed to surround the substrate on the substrate support. The lift mechanism is configured to move the edge ring to an upper limit. The lift mechanism includes a conductive ring and an actuator. The conductive ring is disposed to surround the electrostatic chuck. The actuator is configured to move the conductive ring, with the edge ring supported thereon, up and down together with the edge ring. The conductive ring has a gas flow passage and one or more gas holes. The one or more gas holes are connected to the gas flow generator via the gas flow passage. The one or more gas holes include at least one gas hole. The at least one gas hole opens toward a gap between the conductive ring and the electrostatic chuck.

[0006] According to one exemplary embodiment, particle generation is suppressed.

[0007] FIG. 1 is a diagram illustrating an example of the configuration of a plasma processing system. FIG. 2 is a diagram illustrating an example of the configuration of an inductively coupled plasma processing apparatus. FIG. 3 is a partially enlarged cross-sectional view of a substrate support in a plasma processing apparatus according to an exemplary embodiment. FIG. 4 is a partially enlarged cross-sectional view of a substrate support in a plasma processing apparatus according to an exemplary embodiment. FIG. 5 is a perspective view of a conductive ring according to an exemplary embodiment. FIG. 6(a) is a top view of an exemplary electrostatic chuck. FIG. 6(b) is a top view of another exemplary electrostatic chuck. FIG. 7 is a partially enlarged cross-sectional view of a substrate support in a plasma processing apparatus according to another exemplary embodiment. FIG. 8 is a partially enlarged cross-sectional view of a substrate support in a plasma processing apparatus according to yet another exemplary embodiment.

[0008] Various exemplary embodiments will be described in detail below with reference to the drawings, in which the same or equivalent parts are designated by the same reference numerals.

[0009] FIG. 1 is a diagram illustrating an exemplary configuration of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing apparatus 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing apparatus 1 is an example of a substrate processing apparatus. The plasma processing apparatus 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 in the plasma processing space and has a substrate support surface for supporting a substrate.

[0010] 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 (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 generator has a frequency in the range of 100 kHz to 10 GHz. Therefore, AC signals include RF (Radio Frequency) signals and microwave signals. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0011] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform the various steps described in this disclosure. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to perform the various steps 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 is realized by, for example, a computer 2a. The control unit 2 may include a processing unit 2a1, a memory unit 2a2, and a communication interface 2a3. The functions performed by the processing unit 2a1 described in this disclosure may be implemented in circuitry or processing circuitry, including general-purpose processors, application-specific processors, integrated circuits, ASICs (Application Specific Integrated Circuits), CPUs (Central Processing Units), conventional circuitry, and / or combinations thereof, programmed to perform the described functions. A processor is considered to be a circuit or processing circuit including transistors and other circuitry. The processor may also be a programmed processor that executes a program stored in the memory unit 2a2. This program may be stored in the memory 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 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).In this disclosure, a circuit, unit, or means is hardware that is programmed to implement or configured to implement a described function. The hardware may be any hardware described in this disclosure or any hardware that is programmed to implement or known to implement the described function. If the hardware is a processor, which is considered a type of circuit, the circuit, means, or unit is a combination of hardware and software used to configure the hardware and / or processor.

[0012] The following describes an example of the configuration of an inductively coupled plasma processing apparatus as an example of the plasma processing apparatus 1. Fig. 2 is a diagram for explaining an example of the configuration of an inductively coupled plasma processing apparatus.

[0013] The inductively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply system 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 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.

[0014] 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 plan view. The substrate W is disposed on the central region 111a of the main body 111, and the ring assembly 112 is disposed on the annular region 111b of the main body 111 so as to surround the substrate W on the central region 111a of the main body 111. Therefore, the central region 111a is also called a substrate support surface for supporting the substrate W, and the annular region 111b is also called a ring support surface for supporting the ring assembly 112.

[0015] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The conductive member of the base 1110 may function as a bias electrode. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic chuck electrode 1111b disposed within the ceramic member 1111a. The electrostatic chuck electrode 1111b is also referred to as a clamping electrode. In one embodiment, the electrostatic chuck electrode 1111b is electrically connected or coupled to a chuck power supply. The chuck power supply may be a DC power supply or an AC power supply. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Note that another member surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member, may have the annular region 111b. In this case, the ring assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating member, or may be disposed on both the electrostatic chuck 1111 and the annular insulating member. Furthermore, at least one bias electrode electrically connected to or coupled to the power source 31 and / or the power source 32 (described later) may be disposed within the ceramic member 1111a. Note that the conductive member of the base 1110 and the bias electrode within the ceramic member 1111a may function as multiple bias electrodes. Alternatively, the electrostatic chuck electrode 1111b may function as a bias electrode. Therefore, the substrate support 11 includes at least one bias electrode.

[0016] 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.

[0017] The substrate support 11 may also include a temperature adjustment module configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a gas passage 1110a, or a combination thereof. A heat transfer fluid such as brine or gas flows through the gas passage 1110a. In one embodiment, the gas passage 1110a is formed in the base 1110, and one or more heaters are disposed in the ceramic member 1111a of the electrostatic chuck 1111. The substrate support 11 may also include a heat transfer gas supply configured to supply a heat transfer gas to a gap between the backside of the substrate W and the central region 111a.

[0018] 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.

[0019] The gas supply unit 20 may include at least one gas source 21 and at least one flow 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 through a corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply unit 20 may include at least one flow modulation device that modulates or pulses the flow rate of the at least one process gas.

[0020] The power supply system 30 includes a power supply 31 electrically connected or coupled to the plasma processing chamber 10. In one embodiment, the power supply 31 is electrically connected or coupled to the plasma processing chamber 10 via at least one impedance matcher. The impedance matcher may be a mechanically controlled matcher or an electronically controlled matcher. The power supply 31 is configured to supply at least one RF signal (RF power) to at least one bias electrode and the antenna 14. This generates plasma from at least one processing gas supplied to the plasma processing space 10s. Therefore, the power supply 31 can function as at least a part of the plasma generation unit 12. Furthermore, by supplying a bias RF signal to the at least one bias electrode, a bias potential is generated on the substrate W, thereby attracting ions in the formed plasma to the substrate W.

[0021] The power supply 31 includes a first RF generator 31a and a second RF generator 31b. The first RF generator 31a is electrically connected or coupled to the antenna 14 and configured to generate a source RF signal (source RF power) to generate plasma in the plasma processing space 10s. In one embodiment, the first RF generator 31a is electrically connected or coupled to the antenna 14 via at least one impedance matcher. 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 generator 31a may be configured to generate multiple source RF signals having different frequencies. The generated one or more source RF signals are supplied to the antenna 14.

[0022] The second RF generator 31b is electrically connected or coupled to at least one bias electrode and configured to generate a bias RF signal (bias RF power). In one embodiment, the second RF generator 31b is electrically connected or coupled to the at least one bias electrode via at least one impedance matcher. 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 lower frequency than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency within a range of 100 kHz to 60 MHz. In one embodiment, the second RF generator 31b may be configured to generate multiple bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one bias electrode. In various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0023] The power supply system 30 may also include a power supply 32 electrically connected or coupled to the plasma processing chamber 10. The power supply 32 includes a voltage generator 32a. In one embodiment, the voltage generator 32a is electrically connected or coupled to at least one bias electrode and configured to generate a voltage signal. The generated voltage signal is applied to the at least one bias electrode.

[0024] In various embodiments, the voltage signal may be pulsed. In this case, the voltage generator 32a functions as a voltage pulse generator configured to generate a sequence of voltage pulses. Thus, the sequence of voltage pulses is applied to at least one bias electrode. In one embodiment, the sequence of voltage pulses includes multiple cycles, each cycle including a burst of voltage pulses during a first period and a constant reference voltage during a second period. That is, the bursts of voltage pulses are repeated in the sequence of voltage pulses. The absolute value of the voltage level of the voltage pulses is greater than the absolute value of the voltage level of the reference voltage. The voltage pulses may have an arbitrary waveform, such as a rectangular, trapezoidal, triangular, or combination thereof, and the arbitrary waveform may change over time. The voltage pulses may have positive polarity or negative polarity. Furthermore, the sequence of voltage pulses may include one or more positive voltage pulses and one or more negative voltage pulses within one cycle. The voltage generator 32a may be provided in addition to the power supply 31 or may be provided instead of the second RF generator 31b.

[0025] 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 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.

[0026] The exhaust system 40 may be connected to, for example, a gas exhaust port 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is regulated by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0027] A plasma processing apparatus 1 according to one exemplary embodiment will be described below with reference to FIGS. 3, 4, 5, 6(a), and 6(b). FIG. 3 is a partially enlarged cross-sectional view of a substrate support in a plasma processing apparatus according to one exemplary embodiment. FIG. 4 is a partially enlarged cross-sectional view, different from FIG. 3, of a substrate support in a plasma processing apparatus according to one exemplary embodiment. FIG. 5 is a perspective view of a conductive ring according to one exemplary embodiment. FIG. 3 is a partially enlarged cross-sectional view including a cross section of a conductive ring 51 taken along line III-III in FIG. 5. FIG. 4 is a partially enlarged cross-sectional view including a cross section of a conductive ring 51 taken along line IV-IV in FIG. 5. FIG. 6(a) is a top view of an example of an electrostatic chuck. FIG. 6(b) is a top view of another example of an electrostatic chuck.

[0028] As described above, the substrate support 11 is configured to support an edge ring UR (upper edge ring). The edge ring UR is part of the ring assembly 112. The edge ring UR is disposed to surround the substrate W on the substrate support 11. The edge ring UR may be formed from an electrically conductive material such as silicon, silicon carbide, tungsten, etc.

[0029] The substrate support 11 includes a base 1110 and an electrostatic chuck 1111 on the base 1110, as described above. The base 1110 is an electrically conductive member or includes an electrically conductive member therein. At least one bias power supply, such as the second RF generator 31b and / or the voltage generator 32a, is electrically coupled to the base 1110 (or its conductive member). The at least one bias power supply is configured to generate an electrical bias to attract ions from the plasma to the substrate W on the substrate support 11. The electrical bias includes a sequence of bias RF signals and / or voltage pulses as described above.

[0030] The electrostatic chuck 1111 is disposed on a base 1110. The electrostatic chuck 1111 includes a first portion P1 and a second portion P2. The first portion P1 has a substrate support surface (i.e., a central region 111a) as its upper surface. The first portion P1 and the substrate support surface have a substantially circular planar shape. The central axis of the first portion P1 and the substrate support surface is the central axis of the substrate support part 11. The first portion P1 includes the electrostatic chuck electrode 1111b described above. When a DC voltage is applied to the electrostatic chuck electrode 1111b from a DC power supply, an electrostatic attractive force is generated between the first portion P1 and the substrate W. The first portion P1 holds the substrate W by the generated electrostatic attractive force.

[0031] The second portion P2 extends circumferentially around the central axis of the substrate support 11 to surround the first portion P1. The second portion P2 has a ring support surface (i.e., an annular region 111b) as its upper surface. The second portion P2 and the ring support surface have a substantially annular planar shape. The second portion P2 may include at least one electrostatic electrode. The second portion P2 may include electrodes BEa and BEb as the at least one electrostatic electrode. The electrodes BEa and BEb constitute bipolar electrodes. A voltage is applied to the electrodes BEa and BEb from at least one power supply so as to generate a potential difference between them. This generates an electrostatic attractive force between the edge ring UR and the second portion P2. The second portion P2 holds the edge ring UR by the generated electrostatic attractive force.

[0032] In one embodiment, the ring support surface extends at a position lower than the substrate support surface. In this case, the first portion P1 includes a sidewall surface 111s extending between the substrate support surface and the ring support surface. In this case, an edge ring LR (lower edge ring) may be disposed along the sidewall surface 111s and on the ring support surface. The edge ring LR constitutes part of the ring assembly 112. The edge ring LR may be formed from a conductive material such as silicon, silicon carbide, tungsten, or the like. Alternatively, the edge ring LR may be formed from an insulating material such as quartz. In this case, the edge ring UR is disposed on the edge ring LR. The ring support surface and the sidewall surface 111s are protected by the edge ring LR.

[0033] 3 , the substrate support 11 may further include a cover ring CR and an insulating member IM. The insulating member IM may be made of an insulating material such as quartz and may have a generally cylindrical shape. The insulating member IM may extend in the circumferential direction around the central axis of the substrate support 11 so as to surround the base 1110 and the electrostatic chuck 1111. The cover ring CR may have a generally disk shape and may be disposed on the insulating member IM so as to surround the edge ring UR.

[0034] The plasma processing apparatus 1 further includes a lift mechanism 50 and a gas flow generator GF. The lift mechanism 50 includes a conductive ring 51 and an actuator 53. In one embodiment, the lift mechanism 50 may include at least one rod 52 and at least one connecting member 54.

[0035] In one example, the conductive ring 51 is formed of a metal or conductive material such as aluminum and has a generally ring shape. The conductive ring 51 is configured to move the edge ring UR up and down while supporting the edge ring UR thereon. The conductive ring 51 is arranged to surround the electrostatic chuck 1111. For example, the conductive ring 51 extends circumferentially around the central axis of the substrate support 11 inside the insulating member IM so as to surround the base 1110 and the electrostatic chuck 1111. The conductive ring 51 may be configured to be electrically coupled to the edge ring UR while supporting the edge ring UR thereon. That is, the conductive ring 51 is configured to be conductively or capacitively coupled to the edge ring UR while supporting the edge ring UR thereon. In the example of FIG. 3 , the conductive ring 51 is electrically connected to the edge ring UR while supporting the edge ring UR thereon. Note that the exposed surface of the conductive ring 51 may be covered with a plasma-resistant film. This film may be made of a material such as aluminum oxide or yttrium fluoride, and may be formed by techniques such as anodizing or thermal spraying.

[0036] The at least one rod 52 extends in the vertical direction below the conductive ring 51. The at least one rod 52 may be insulating. In this case, it is possible to suppress the electrical bias from flowing into the actuator 53 via the at least one rod 52. In one embodiment, the lift mechanism 50 may include a plurality of rods 52 as the at least one rod 52. The plurality of rods 52 are arranged along the circumferential direction around the central axis of the substrate support 11. The plurality of rods 52 may be arranged at equal intervals along the circumferential direction.

[0037] The actuator 53 is disposed below the at least one rod 52 and is connected to the at least one rod 52. The actuator 53 is configured to move the edge ring up and down via the at least one rod 52 and the conductive ring 51. The actuator 53 may be, for example, a pneumatic or hydraulic cylinder, or a motor.

[0038] The at least one connecting member 54 provides an electrical connection between the conductive ring 51 and the base 1110 (or a conductive member thereof). The at least one connecting member 54 is configured to maintain the electrical connection in response to movement of the conductive ring 51. The at least one connecting member 54 may be configured to be deformable in response to movement of the conductive ring 51. Note that when the lift mechanism 50 includes a plurality of rods 52, the at least one connecting member 54 may include a plurality of connecting members 54.

[0039] 3 , at least one connecting member 54 includes an upper portion 54a, a deformed portion 54b, and a lower portion 54c. The upper portion 54a, the deformed portion 54b, and the lower portion 54c are formed from a conductive material. The upper portion 54a is disposed directly below the conductive ring 51 and is fixed to the conductive ring 51. The upper portion 54a is electrically connected to the conductive ring 51. The lower portion 54c is disposed below the upper portion 54a and is fixed to the base 1110. The lower portion 54c is electrically connected to the base 1110.

[0040] The deformed portion 54b extends between the upper portion 54a and the lower portion 54c. The upper end of the deformed portion 54b is fixed to the upper portion 54a, and the lower end of the deformed portion 54b is fixed to the lower portion 54c. The deformed portion 54b is electrically connected to the upper portion 54a and the lower portion 54c. The deformed portion 54b may be a bellows as shown in FIG. 3.

[0041] At least one rod 52 penetrates the lower portion 54c, passes through the deformed portion 54b, and extends to a region directly below the upper portion 54a. When the at least one rod 52 is moved upward by the actuator 53, the edge ring UR is moved upward via the upper portion 54a and the conductive ring 51. The edge ring UR is moved upward in accordance with a decrease in its thickness to reduce the difference between the upper end position of the plasma sheath on the substrate W and the upper end position of the plasma sheath on the edge ring UR. In the plasma processing apparatus 1, even when the edge ring UR is moved upward from the electrostatic chuck 1111, the connecting member 54 maintains electrical connection between the base 1110 and the edge ring UR. In the plasma processing apparatus 1, the edge ring UR is not electrically floating, so that the edge ring UR can reduce the difference between the upper end position of the plasma sheath on the substrate W and the upper end position of the plasma sheath on the edge ring UR.

[0042] The connecting member 54 may be a cylindrical member having a plurality of slits formed in its sidewall surface so as to be elastically deformable in the longitudinal direction. For example, the connecting member 54 may be a flexure.

[0043] The lift mechanism 50 is configured to move the edge ring UR up and down. The actuator 53 is configured to move the conductive ring 51, which supports the edge ring UR thereon, up and down together with the edge ring UR.

[0044] The conductive ring 51 provides a gas flow path FP and one or more gas holes 51x. The gas flow path FP is configured to allow a gas to flow. The one or more gas holes 51x are connected to a gas flow generator GF via the gas flow path FP. The one or more gas holes 51x include at least one gas hole 51a (at least one first gas hole). The at least one gas hole 51a opens toward the gap between the conductive ring 51 and the electrostatic chuck 1111. In the examples shown in FIGS. 3 and 4 , the at least one gas hole 51a opens in an inner circumferential surface 510 of the conductive ring 51. The inner circumferential surface 510 faces the electrostatic chuck 1111. The inner circumferential surface 510 extends circumferentially around the central axis of the substrate support 11 to surround the electrostatic chuck 1111. The at least one gas hole 51a is configured to generate a gas flow in the gap between the conductive ring 51 and the electrostatic chuck 1111.

[0045] In the plasma processing apparatus 1, in which the edge ring UR is moved up and down together with the conductive ring 51 by the actuator 53, a gap is defined between the conductive ring 51 and the electrostatic chuck 1111. By-products may be formed in the gap during plasma processing. For example, by-products are formed by reaction with plasma generated from a processing gas introduced into the plasma processing space 10s for plasma processing. The by-products formed in the gap may peel off from the surface of the conductive ring 51 and / or the electrostatic chuck 1111, potentially generating particles. In the plasma processing apparatus 1, a gas flow is generated in the gap between the conductive ring 51 and the electrostatic chuck 1111 by at least one gas hole 51a connected to the gas flow generator GF via the gas flow path FP, making it difficult for by-products to form in the gap. As a result, the plasma processing apparatus 1 suppresses particle generation.

[0046] In one embodiment, the gas flow generator GF may be a gas supply unit 55. One or more gas holes 51x are connected to the gas supply unit 55 via a gas flow path FP. In one example, the gas supply unit 55 supplies He gas. The gas supply unit 55 may include a gas flow path, a flow controller disposed in the gas flow path, a valve disposed in the gas flow path, and / or a gas source connected to the gas flow path. The He gas supplied from the gas supply unit 55 to the gas flow path FP is ejected from at least one gas hole 51a into the gap between the conductive ring 51 and the electrostatic chuck 1111. Therefore, a gas flow is generated that flows from the gap between the conductive ring 51 and the electrostatic chuck 1111 into the plasma processing space, making it difficult for by-products to be formed in the gap.

[0047] In one embodiment, the electrostatic chuck 1111 includes at least one porous member 1111c. The at least one porous member 1111c provides a plurality of pores. In one example, the at least one porous member 1111c is formed from ceramic. The at least one porous member 1111c constitutes a part of the side surface of the electrostatic chuck 1111. The porous member 1111c faces at least one gas hole 51a. A process gas that has entered the gap between the conductive ring 51 and the electrostatic chuck 1111 is adsorbed as a by-product to the at least one porous member 1111c by the gas flow ejected from the at least one gas hole 51a. The by-product adsorbed to the porous member 1111c is difficult to peel off, resulting in suppression of particle generation.

[0048] 6A, in the electrostatic chuck 1111, the at least one porous member 1111c includes a single porous member 1111d. The single porous member 1111d extends in the circumferential direction around the central axis of the substrate support 11. The at least one gas hole 51a may include a plurality of gas holes 51a. For example, the plurality of gas holes 51a are arranged in the circumferential direction around the central axis of the substrate support 11. The plurality of gas holes 51a each open toward the single porous member 1111d.

[0049] 6B, in an electrostatic chuck 1111A, the at least one porous member 1111c includes a plurality of porous members 1111e. The plurality of porous members 1111e are arranged in the circumferential direction around the central axis of the substrate support part 11. The plurality of gas holes 51a open toward the plurality of porous members 1111e, respectively.

[0050] In one embodiment, as shown in FIGS. 3 and 4 , the conductive ring 51 includes a first upper surface 511 and a second upper surface 512. The first upper surface 511 supports the edge ring UR thereon. The second upper surface 512 is positioned to surround the first upper surface 511 and is positioned lower than the first upper surface 511. The one or more gas holes 51x may include at least one gas hole 51b (at least one second gas hole). The at least one gas hole 51b opens in the second upper surface 512. The at least one gas hole 51b is connected to the gas supply unit 55 via a gas flow path FP. He gas supplied from the gas supply unit 55 to the gas flow path FP is ejected upward from the at least one gas hole 51b, so that by-products are unlikely to form on the second upper surface 512. By-products are unlikely to form in the gap between the edge ring UR and the cover ring CR, which is positioned above the at least one gas hole 51b.

[0051] In one embodiment, the conductive ring 51 may include an outer peripheral surface 513. The outer peripheral surface 513 extends between the first upper surface 511 and the second upper surface 512. The one or more gas holes 51x may include at least one gas hole 51c (at least one third gas hole). The at least one gas hole 51c opens in the outer peripheral surface 513. The at least one gas hole 51c is connected to a gas supply unit 55 via a gas flow path FP. He gas supplied from the gas supply unit 55 to the gas flow path FP is ejected outward from the at least one gas hole 51c, so by-products are unlikely to be formed on the outer peripheral surface 513. The outer peripheral surface 513 faces the inner peripheral surface of the insulating member IM. By-products are unlikely to be formed in the gap between the conductive ring 51 and the insulating member IM.

[0052] In one embodiment, the one or more gas holes 51x may include at least one gas hole 51d (at least one other gas hole). In the examples shown in FIGS. 3 and 4 , the at least one gas hole 51d opens in the inner circumferential surface 514. The inner circumferential surface 514 extends circumferentially around the central axis of the substrate support 11 to surround the base 1110. The inner circumferential surface 514 faces the base 1110. In the conductive ring 51, the inner circumferential surface 514 is located radially outward of and below the inner circumferential surface 510. The at least one gas hole 51d is connected to the gas flow path FP. The at least one gas hole 51d generates a gas flow in the gap between the conductive ring 51 and the base 1110, making it difficult for by-products to be formed in the gap.

[0053] In one embodiment, the conductive ring 51 may include one or more heaters 51h. Because the conductive ring 51 is heated by the one or more heaters 51h, by-products are less likely to form on the surface of the conductive ring 51. As a result, particle generation is suppressed. As shown in each of FIGS. 3 to 5, the one or more heaters 51h may be disposed closer to the outer peripheral surface 515 (another outer peripheral surface) than the inner peripheral surface 510. As described above, the inner peripheral surface 510 faces the electrostatic chuck 1111. At least one gas hole 51a opens in the inner peripheral surface 510. The outer peripheral surface 515 extends outward relative to the inner peripheral surface 510. In the conductive ring 51, the outer peripheral surface 515 is located radially outward of and below the outer peripheral surface 513. The outer peripheral surface 515 is the outermost outer peripheral surface of the conductive ring 51 in the radial direction. 3 and 4, the outer circumferential surface 515 extends downward from the outer edge of the second upper surface 512. One or more heaters 51h are disposed near the outer circumferential surface 515, so that the inner circumferential surface 510 opposite the outer circumferential surface 515 is uniformly heated. As a result, by-products are less likely to form on the inner circumferential surface 510.

[0054] In one embodiment, the conductive ring 51 may include a first upper surface 511 (upper surface), at least one first lower surface 516, and at least one second lower surface 517. In the examples shown in FIGS. 3-5, the at least one first lower surface 516 includes a plurality of first lower surfaces 516, and the at least one second lower surface 517 includes a plurality of second lower surfaces 517. As described above, the first upper surface 511 supports the edge ring UR thereon. As shown in FIGS. 3 and 5, respectively, the at least one first lower surface 516 extends below the first upper surface 511. As shown in FIGS. 4 and 5, respectively, the at least one second lower surface 517 extends below the at least one first lower surface 516. In one embodiment, at least one rod 52 extends vertically below the at least one first lower surface 516. The at least one first lower surface 516 is supported by the at least one rod 52. For example, at least one rod 52 may support at least one first lower surface 516 via at least one connecting member 54 .

[0055] In one embodiment, the one or more heaters 51h may include at least one first heater 56 and at least one second heater 57. The at least one first heater 56 is disposed closer to the at least one first lower surface 516 than to the first upper surface 511. The at least one second heater 57 is disposed closer to the at least one second lower surface 517 than to the first upper surface 511. In the examples shown in FIGS. 3 to 5 , the at least one first heater 56 includes a plurality of first heaters 56, and the at least one second heater 57 includes a plurality of second heaters 57. The plurality of first heaters 56 are disposed closer to the plurality of first lower surfaces 516 than to the first upper surface 511, respectively. The plurality of second heaters 57 are disposed closer to the plurality of second lower surfaces 517 than to the first upper surface 511, respectively. In the conductive ring 51, the first heater 56 and the second heater 57 are disposed near the first lower surface 516 and the second lower surface 517, respectively. Therefore, the conductive ring 51 is more likely to be heated uniformly than a conductive ring configured such that the first heater 56 and the second heater 57 are disposed near the first upper surface 511. As a result, by-products are less likely to form on the surface of the conductive ring 51.

[0056] 3-5, respectively, the at least one first lower surface 516 is located opposite the second upper surface 512. The at least one second lower surface 517 is located opposite the second upper surface 512 and below the at least one first lower surface 516. The at least one first heater 56 is located closer to the at least one first lower surface 516 than to the second upper surface 512. The at least one second heater 57 is located closer to the at least one second lower surface 517 than to the second upper surface 512.

[0057] In one embodiment, the substrate support 11 may include an insulating member IM as described above. The insulating member IM extends circumferentially around the central axis of the substrate support 11 to surround the conductive ring 51. As described above, the outer circumferential surface 515 faces the insulating member IM. The one or more gas holes 51x may include at least one gas hole 51e (at least one other gas hole). The at least one gas hole 51e opens toward the gap between the conductive ring 51 and the insulating member IM. In one example, the at least one gas hole 51e opens in the outer circumferential surface 515. In the plasma processing apparatus 1, the at least one gas hole 51e connected to the gas flow generator GF via the gas flow path FP generates a gas flow in the gap between the conductive ring 51 and the insulating member IM, making it difficult for by-products to be formed in the gap.

[0058] In one embodiment, the gas flow path FP may include a first gas flow path FP1. At least one connecting member 54 provides a second gas flow path FP2. The second gas flow path FP2 is in communication with the first gas flow path FP1. At least one rod 52 provides a third gas flow path FP3. The third gas flow path FP3 is in communication with the second gas flow path FP2. In one embodiment, the base 1110 provides a gas flow path FP4 that is separate from the gas flow path FP. The separate gas flow path FP4 is in communication with the gas flow path FP of the conductive ring 51.

[0059] In one embodiment, the base 1110 may include a first upper surface 1110b and a second upper surface 1110c. The first upper surface 1110b supports the electrostatic chuck 1111 thereon. The second upper surface 1110c is positioned to surround the first upper surface 1110b and is positioned lower than the first upper surface 1110b. The base 1110 may have at least one gas hole 1110d. The at least one gas hole 1110d opens in the second upper surface 1110c. The at least one gas hole 1110d is connected to another gas flow path FP4 of the base 1110. The at least one gas hole 1110d is in communication with the gas flow path FP (first gas flow path FP1) of the conductive ring 51.

[0060] A plasma processing apparatus according to another exemplary embodiment will now be described. Fig. 7 is a partially enlarged cross-sectional view of a substrate support portion of the plasma processing apparatus according to another exemplary embodiment. The plasma processing apparatus 1A shown in Fig. 7 will be described below from the viewpoint of differences from the plasma processing apparatuses 1 shown in Figs. 3 and 4, respectively, and overlapping descriptions will be omitted as appropriate.

[0061] In one embodiment, the gas flow generator GF may be an exhaust system 40. In the plasma processing apparatus 1A, at least one gas hole 51a is connected to the exhaust system 40 via a gas flow path FP. In the example shown in FIG. 7 , the exhaust system 40 is connected to one or more gas holes 51x via a third gas flow path FP3, a second gas flow path FP2, and a first gas flow path FP1 (gas flow path FP). The exhaust system 40 is connected to one or more gas holes 51x via the gas flow path FP. The exhaust system 40 is connected to each of at least one gas hole 51a, 51b, 51c, 51d, and 51e via the gas flow path FP. The exhaust system 40 may include a gas flow path, a flow rate controller disposed in the path, a valve disposed in the path, and / or a pump connected to the path. Since the process gas present in the gap between the conductive ring 51 and the electrostatic chuck 1111 is exhausted by the exhaust system 40, by-products are less likely to be formed in the gap. In the plasma processing apparatus 1A, the electrostatic chuck 1111 does not include at least one porous member 1111c.

[0062] A plasma processing apparatus according to yet another exemplary embodiment will be described below. Fig. 8 is a partially enlarged cross-sectional view of a substrate support portion of the plasma processing apparatus according to yet another exemplary embodiment. Below, the plasma processing apparatus 1B shown in Fig. 8 will be described from the viewpoint of differences from the plasma processing apparatus 1A shown in Fig. 7, and overlapping descriptions will be omitted as appropriate.

[0063] In the plasma processing apparatus 1B, the insulating member IM provides a gas exhaust port IMh that communicates with the exhaust system 40. At least one gas hole 51e (at least one second gas hole) that opens toward the gap between the conductive ring 51 and the insulating member IM communicates with the gas exhaust port IMh through the gap between the conductive ring 51 and the insulating member IM. At least one gas hole 51a and at least one gas hole 51e are connected via a gas flow path FP. Therefore, the process gas present in the gap between the conductive ring 51 and the electrostatic chuck 1111 and the process gas present in the gap between the conductive ring 51 and the insulating member IM are exhausted by the exhaust system 40.

[0064] Although various exemplary embodiments have been described above, the present invention is not limited to the above-described exemplary embodiments, and various additions, omissions, substitutions, and modifications may be made. Furthermore, elements in different embodiments may be combined to form other embodiments.

[0065] The number of the one or more gas holes 51x may be multiple or single. The number of each of the at least one gas holes 51a, 51b, 51c, 51d, and 51e may be multiple or single. The number of the at least one gas hole 1110d may be multiple or single. The at least one connecting member 54 may not provide the second gas flow path FP2. The at least one rod 52 may not provide the third gas flow path FP3. The plasma processing apparatus may not include a gas flow generator GF. The lift mechanism may not include an actuator 53.

[0066] Various exemplary embodiments included in the present disclosure are now described in [E1] to [E16] below.

[0067] [E1] A plasma processing apparatus comprising: a chamber; a plasma generation unit configured to generate plasma in the chamber; a substrate support unit disposed in the chamber, the substrate support unit including a base and an electrostatic chuck on the base; an edge ring disposed to surround the substrate on the electrostatic chuck; a lift mechanism configured to move the edge ring up and down, the lift mechanism including a conductive ring disposed to surround the electrostatic chuck and an actuator configured to move the conductive ring, with the edge ring supported thereon, up and down together with the edge ring; and a gas flow generator, wherein the conductive ring provides a gas flow path and one or more gas holes connected to the gas flow generator via the gas flow path, the one or more gas holes including at least one gas hole opening toward a gap between the conductive ring and the electrostatic chuck. [E2] The plasma processing apparatus of E1, wherein the gas flow generator is a gas supply unit, and the one or more gas holes are connected to the gas supply unit via the gas flow path. [E3] The plasma processing apparatus of E2, wherein the electrostatic chuck includes at least one porous member constituting at least a portion of a side surface of the electrostatic chuck, and the at least one gas hole opens toward the at least one porous member. [E4] The plasma processing apparatus of E3, wherein the at least one gas hole includes a plurality of gas holes, and the at least one porous member includes a single porous member extending circumferentially around a central axis of the substrate support, and the plurality of gas holes open toward the single porous member. [E5] The plasma processing apparatus of E3, wherein the at least one gas hole includes a plurality of gas holes, and the at least one porous member includes a plurality of porous members, and the plurality of gas holes each open toward the plurality of porous members.[E6] The plasma processing apparatus according to E2 to E5, wherein the at least one gas hole is at least one first gas hole, the conductive ring includes a first upper surface supporting the edge ring thereon, and a second upper surface positioned to surround the first upper surface and positioned lower than the first upper surface, and the one or more gas holes further include at least one second gas hole opening in the second upper surface. [E7] The plasma processing apparatus according to E6, wherein the conductive ring includes an outer circumferential surface extending between the first upper surface and the second upper surface, and the one or more gas holes further include at least one third gas hole opening in the outer circumferential surface. [E8] The plasma processing apparatus according to E1, wherein the gas flow generator is an exhaust system, and the one or more gas holes are connected to the exhaust system via the gas flow path. [E9] The plasma processing apparatus according to E8, wherein the at least one gas hole is at least one first gas hole, and further comprises an insulating member extending circumferentially around a central axis of the substrate support so as to surround the conductive ring, the insulating member providing a gas exhaust port communicating with the exhaust system, and the one or more gas holes further comprising at least one second gas hole opening toward a gap between the conductive ring and the insulating member, the at least one second gas hole communicating with the gas exhaust port via the gap between the conductive ring and the insulating member. [E10] The plasma processing apparatus according to any one of E1 to E9, wherein the one or more gas holes further include at least one other gas hole opening toward a gap between the conductive ring and the base. [E11] The plasma processing apparatus according to any one of E1 to E9, wherein the conductive ring includes one or more heaters. [E12] The plasma processing apparatus according to E11, wherein the conductive ring includes an inner circumferential surface and another outer circumferential surface extending outwardly relative to the inner circumferential surface, the inner circumferential surface providing an opening for the at least one gas hole, and the one or more heaters are positioned closer to the another outer circumferential surface than to the inner circumferential surface.[E13] The plasma processing apparatus according to E11 or 12, wherein the lift mechanism further comprises: at least one rod extending vertically below the conductive ring; and the actuator configured to move the edge ring up and down via the at least one rod and the conductive ring, wherein the conductive ring comprises: an upper surface supporting the edge ring thereon; at least one first lower surface extending below the upper surface, the at least one rod extending vertically below the at least one first lower surface supported by the at least one rod; and at least one second lower surface extending below the at least one first lower surface, wherein the one or more heaters comprise: at least one first heater arranged closer to the at least one first lower surface than the upper surface; and at least one second heater arranged closer to the at least one second lower surface than the upper surface. [E14] The plasma processing apparatus according to any one of E1 to E13, wherein the substrate support further has an insulating member extending circumferentially around a central axis of the substrate support so as to surround the conductive ring, and the one or more gas holes further include at least one other gas hole opening toward a gap between the conductive ring and the insulating member.[E15] The plasma processing apparatus of any one of E1 to E14, further comprising: a bias power supply configured to generate an electric bias to attract ions from the plasma to the substrate on the substrate support; the edge ring being conductive; the plasma generation unit having a high frequency power supply; the base being electrically coupled to the bias power supply and / or the high frequency power supply; and the lift mechanism further comprising: at least one rod extending vertically below the conductive ring; an actuator configured to move the edge ring up and down via the at least one rod and the conductive ring; and a connecting member providing an electrical connection between the conductive ring and the base, the connecting member being configured to maintain the electrical connection in accordance with movement of the conductive ring; and the conductive ring electrically coupling the edge ring while supporting the edge ring placed thereon. [E16] A plasma processing apparatus comprising: a chamber; a substrate support disposed within the chamber; an edge ring disposed to surround a substrate on the substrate support; a lift mechanism configured to move the edge ring up and down; and a plasma generation unit configured to generate plasma within the chamber, wherein the substrate support has a base and an electrostatic chuck disposed on the base; the lift mechanism has a conductive ring configured to move the edge ring up and down while supporting the edge ring thereon, the conductive ring being disposed to surround the electrostatic chuck; the conductive ring having: a gas flow path configured to allow a gas to flow; and one or more gas holes connected to the gas flow path, wherein the one or more gas holes include at least one gas hole opening toward a gap between the conductive ring and the electrostatic chuck, the at least one gas hole configured to generate a gas flow in the gap.

[0068] The configurations of the exemplary embodiments disclosed in E1 to E15 may be applied to the plasma processing apparatus disclosed in E16.

[0069] From the foregoing, it will be understood that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the appended claims.

[0070] 1, 1A, 1B... plasma processing apparatus, IMh... gas exhaust port, 10... chamber, 11... substrate support part, 12... plasma generation part, 55... gas supply part, 40... exhaust system, 50... lift mechanism, 51... conductive ring, 51a, 51b, 51c, 51d, 51e, 51x... gas hole, 1110d... gas hole, 51h... heater, 56... first heater, 57... second heater, 52... rod, 53... actuator Eta, 54...connecting member, 510...inner surface, 511...first upper surface, 512...second upper surface, 513, 515...outer surface, 516...first lower surface, 517...second lower surface, 1110...base, FP...gas flow path, 1111, 1111A...electrostatic chuck, 1111c, 1111d, 1111e...porous member, CR...covering, GF...gas flow generator, IM...insulating member, UR...edge ring, W...substrate.

Claims

1. A plasma processing apparatus comprising: a chamber; a plasma generation unit configured to generate plasma in the chamber; a substrate support unit disposed in the chamber, the substrate support including a base and an electrostatic chuck on the base; an edge ring disposed to surround the substrate on the electrostatic chuck; a lift mechanism configured to move the edge ring up and down, the lift mechanism including a conductive ring disposed to surround the electrostatic chuck and an actuator configured to move the conductive ring, with the edge ring supported thereon, up and down together with the edge ring; and a gas flow generator, wherein the conductive ring provides a gas flow path and one or more gas holes connected to the gas flow generator via the gas flow path, and the one or more gas holes include at least one gas hole opening toward a gap between the conductive ring and the electrostatic chuck.

2. The plasma processing apparatus according to claim 1, wherein the gas flow generator is a gas supply unit, and the one or more gas holes are connected to the gas supply unit via the gas flow path.

3. The plasma processing apparatus according to claim 2, wherein the electrostatic chuck includes at least one porous member that forms at least a part of a side surface of the electrostatic chuck, and the at least one gas hole opens toward the at least one porous member.

4. The plasma processing apparatus according to claim 3, wherein the at least one gas hole includes a plurality of gas holes, the at least one porous member includes a single porous member extending circumferentially around a central axis of the substrate support, and the plurality of gas holes open toward the single porous member.

5. The plasma processing apparatus according to claim 3, wherein the at least one gas hole includes a plurality of gas holes, the at least one porous member includes a plurality of porous members, and the plurality of gas holes open toward the plurality of porous members, respectively.

6. The plasma processing apparatus of claim 2, wherein the at least one gas hole is at least one first gas hole, the conductive ring includes a first upper surface supporting the edge ring thereon, and a second upper surface positioned to surround the first upper surface and positioned lower than the first upper surface, and the one or more gas holes further include at least one second gas hole opening in the second upper surface.

7. The plasma processing apparatus of claim 6, wherein the conductive ring includes an outer circumferential surface extending between the first upper surface and the second upper surface, and the one or more gas holes further include at least one third gas hole opening in the outer circumferential surface.

8. The plasma processing apparatus according to claim 1, wherein the gas flow generator is an exhaust system, and the one or more gas holes are connected to the exhaust system via the gas flow passage.

9. The plasma processing apparatus of claim 8, further comprising: an insulating member extending circumferentially around the central axis of the substrate support so as to surround the conductive ring, the insulating member providing a gas exhaust port communicating with the exhaust system; and the one or more gas holes being at least one second gas hole opening toward a gap between the conductive ring and the insulating member, the at least one second gas hole communicating with the gas exhaust port via the gap between the conductive ring and the insulating member.

10. The plasma processing apparatus according to any one of claims 1 to 9, wherein the one or more gas holes further include at least one other gas hole that opens toward the gap between the conductive ring and the base.

11. The plasma processing apparatus according to any one of claims 1 to 9, wherein the conductive ring includes one or more heaters.

12. The plasma processing apparatus of claim 11, wherein the conductive ring includes an inner circumferential surface and another outer circumferential surface extending outwardly relative to the inner circumferential surface, the inner circumferential surface providing an opening for the at least one gas hole, and the one or more heaters are positioned closer to the other outer circumferential surface than to the inner circumferential surface.

13. The plasma processing apparatus of claim 11, wherein the lift mechanism further comprises: at least one rod extending vertically below the conductive ring; and the actuator configured to move the edge ring up and down via the at least one rod and the conductive ring; the conductive ring including: an upper surface supporting the edge ring thereon; at least one first lower surface extending below the upper surface, the at least one rod extending vertically below the at least one first lower surface supported by the at least one rod; and at least one second lower surface extending below the at least one first lower surface; and the one or more heaters include: at least one first heater positioned closer to the at least one first lower surface than the upper surface; and at least one second heater positioned closer to the at least one second lower surface than the upper surface.

14. A plasma processing apparatus according to any one of claims 1 to 9, wherein the substrate support further comprises an insulating member extending circumferentially around the central axis of the substrate support so as to surround the conductive ring, and the one or more gas holes further include at least one other gas hole opening toward a gap between the conductive ring and the insulating member.

15. The plasma processing apparatus of any one of claims 1 to 9, further comprising: a bias power supply configured to generate an electrical bias to attract ions from the plasma to the substrate on the substrate support; the edge ring being conductive; the plasma generation unit having a high-frequency power supply; the base being electrically coupled to the bias power supply and / or the high-frequency power supply; and the lift mechanism further comprising: at least one rod extending vertically below the conductive ring; an actuator configured to move the edge ring up and down via the at least one rod and the conductive ring; and a connecting member providing an electrical connection between the conductive ring and the base, the connecting member being configured to maintain the electrical connection in response to movement of the conductive ring; and the conductive ring electrically coupling the edge ring while supporting the edge ring placed thereon.

16. A plasma processing apparatus comprising: a chamber; a substrate support disposed within the chamber; an edge ring disposed to surround a substrate on the substrate support; a lift mechanism configured to move the edge ring up and down; and a plasma generation unit configured to generate plasma in the chamber, wherein the substrate support has a base and an electrostatic chuck disposed on the base; the lift mechanism has a conductive ring configured to move the edge ring up and down while supporting the edge ring thereon, the conductive ring being disposed to surround the electrostatic chuck; the conductive ring having: a gas flow path configured to allow a gas to flow; and one or more gas holes connected to the gas flow path, the one or more gas holes including at least one gas hole opening toward a gap between the conductive ring and the electrostatic chuck, the at least one gas hole configured to generate a gas flow in the gap.

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