Substrate processing device

Abstract

Provided is a substrate processing device for positioning an edge ring.　This substrate processing device comprises: an electrostatic chuck having a substrate support surface and a ring support surface, and having a first through hole, through which a lift pin is inserted, in the ring support surface; an edge ring supported by the ring support surface; and a cylindrical member inserted into the first through hole of the electrostatic chuck and having a second through hole. The cylindrical member has a first shaft part inserted into the first through hole of the electrostatic chuck, and a first head part which is a part arranged on the ring support surface of the electrostatic chuck when the first shaft part is inserted into the first through hole of the electrostatic chuck. The edge ring has a first groove part which is provided on a lower surface of the edge ring, and in which the first head part is arranged.

Description

Substrate Processing Equipment

[0001] The present disclosure relates to a substrate processing apparatus.

[0002] Patent Document 1 discloses an apparatus for processing a substrate, the apparatus comprising: a substrate support; an electrostatic chuck disposed on the substrate support and including a first portion, a second portion, and a third portion; and a process kit surrounding the electrostatic chuck, the process kit comprising: a support ring disposed on a surface of the third portion of the electrostatic chuck; an edge ring disposed on a surface of the second portion of the electrostatic chuck and movable independently with respect to the support ring; and a cover ring disposed on the support ring and having a first surface that contacts the support ring.

[0003] Special table 2019-505088 publication

[0004] In one aspect, the present disclosure provides a substrate processing apparatus for positioning an edge ring.

[0005] In order to solve the above problem, according to one aspect, a substrate processing apparatus can be provided, comprising: an electrostatic chuck having a substrate support surface and a ring support surface, the ring support surface having a first through hole through which a lift pin is inserted; an edge ring supported on the ring support surface; and a cylindrical member having a second through hole and inserted into the first through hole of the electrostatic chuck, wherein the cylindrical member has a first shaft portion inserted into the first through hole of the electrostatic chuck and a first head portion that is positioned above the ring support surface of the electrostatic chuck when the first shaft portion is inserted into the first through hole of the electrostatic chuck, and the edge ring is provided on a lower surface of the edge ring and has a first groove portion in which the first head portion is positioned.

[0006] According to one aspect, a substrate processing apparatus for positioning an edge ring can be provided.

[0007] 1 is a diagram illustrating an example of the configuration of a plasma processing system; 2 is a diagram illustrating an example of the configuration of an inductively coupled plasma processing apparatus; 3 is an example of an enlarged cross-sectional view of a substrate support portion according to the first embodiment; 4 is an example of another enlarged cross-sectional view of a substrate support portion according to the first embodiment; 5 is a diagram of a substrate support portion viewed from above; 6 is an example of a perspective view illustrating a positioning structure of an under-ring; 7 is an example of a perspective view illustrating a positioning structure of an under-ring; 8 is an example of a perspective view illustrating a positioning structure of an under-ring; 9 is an example of a schematic view illustrating a positioning structure of an under-ring; 10 is an example of a schematic view illustrating a positioning structure of an under-ring; 11 is an example of a perspective view illustrating a positioning structure of an inner ring; 12 is an example of a perspective view illustrating a positioning structure of an inner ring; 13 is an example of a schematic view illustrating a positioning structure of an inner ring; 14 is an example of a schematic view illustrating a positioning structure of an inner ring; 15 is an example of a schematic view illustrating a positioning structure of an inner ring; 16 is an example of another enlarged cross-sectional view of a substrate support portion according to a second embodiment; 17 is an example of a view illustrating a positioning structure of an inner ring; 18 is an example of a view illustrating a positioning structure of an inner ring; 19 is an example of a view illustrating a positioning structure of an inner ring; 10A and 10B are diagrams illustrating another example of the positioning structure of the inner ring;

[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 an example diagram for explaining an example configuration of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing apparatus (substrate 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 (see FIG. 2), which will be described later, and the gas exhaust port is connected to an exhaust system 40 (see FIG. 2), which will be 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 generated 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), surface wave plasma (SWP), or the like. Various types of plasma generators may be used, including alternating current (AC) plasma generators and direct current (DC) plasma generators. 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. Thus, AC signals include radio frequency (RF) 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 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. This 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).

[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 an example of 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 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 can 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 electrode 1111b disposed within the ceramic member 1111a. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Note that the annular region 111b may also be provided by 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. Furthermore, at least one RF / DC electrode coupled to an RF power supply 31 and / or a DC power supply 32, which will be 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. Note that the conductive member of the base 1110 and the at least one RF / DC electrode may function as multiple bias electrodes. Alternatively, the electrostatic 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 1120 (see FIG. 3, etc., described later) and at least one cover ring 1123 (see FIG. 3, etc., described later). The edge ring 1120 is formed of a conductive or insulating material, and the cover ring 1123 is 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 W to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow passage 1110a, or a combination thereof. A heat transfer fluid such as brine or a gas flows through the flow passage 1110a. In one embodiment, the flow passage 1110a is formed in the base 1110, and one or more heaters are disposed in the ceramic member 1111a of the electrostatic chuck 1111. The substrate support 11 may also include a heat transfer gas supply configured to supply a heat transfer gas to a gap between the back surface of the substrate W and the central region 111a.

[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 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 bias electrode 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 generating 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] 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 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 coupled to at least one bias electrode via at least one impedance matching circuit and is configured to generate a bias RF signal (bias RF power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF 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 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 bias electrode and configured to generate a bias DC signal. The generated bias DC signal is applied to the at least one bias electrode.

[0024] In various embodiments, the bias DC signal may be pulsed. In this case, a sequence of voltage pulses is applied to at least one bias electrode. The voltage pulses may have a rectangular, trapezoidal, triangular, or combination thereof. In one embodiment, a waveform generator for generating the sequence of voltage pulses from the DC signal is connected between the bias DC generator 32a and at least one bias electrode. Thus, the bias DC generator 32a and the waveform generator constitute a voltage pulse generator. The voltage pulses may have positive 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. Note that the bias DC generator 32a may be provided in addition to the RF 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 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.

[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] Next, the substrate support portion 11 according to the first embodiment will be further described with reference to FIGS. 3 to 5 . FIG. 3 is an example of an enlarged cross-sectional view of the substrate support portion 11 according to the first embodiment. FIG. 4 is an example of another enlarged cross-sectional view of the substrate support portion 11 according to the first embodiment. FIG. 5 is a view of the substrate support portion 11 as seen from above. Note that FIGS. 3 and 4 are cross-sectional views of the substrate support portion 11 cut radially, with the left side of the drawing corresponding to the center of the substrate support portion 11 and the right side of the drawing corresponding to the outer periphery of the substrate support portion 11. FIG. 3 is a cross-sectional view at position S1 (shown by a hollow circle in FIG. 5 ) where a positioning structure for an under-ring 1122 (described later) is provided. FIG. 4 is a cross-sectional view at position S2 (shown by a filled circle in FIG. 5 ) where a positioning structure for an inner ring 1121 (described later) is provided.

[0028] 3 and 4 , the main body 111 of the substrate support 11 includes a base 1110 and an electrostatic chuck 1111. The electrostatic chuck 1111 is disposed on the base 1110 via an adhesive layer 1112. The adhesive layer 1112 is disposed between the base 1110 and the electrostatic chuck 1111, and bonds the upper surface of the base 1110 to the lower surface of the electrostatic chuck 1111. The seal member 116 is formed of a material that is corrosion-resistant, plasma-resistant, and heat-resistant, and protects the adhesive layer 1112 from the processing gas, plasma, etc. in the plasma processing space 10s.

[0029] 3, the substrate support unit 11 also has a height adjustment mechanism 15 that adjusts the height of the inner ring 1121, which will be described later. The height adjustment mechanism 15 has an elevation mechanism (not shown) that raises and lowers lift pins 115 arranged in the through holes 1110c of the base 1110. The height adjustment mechanism 15 raises the lift pins 115 above the upper surfaces of the supports 1122b, which will be described later, thereby lifting the inner ring 1121 arranged on the supports 1122b and adjusting the height of the inner ring 1121. The height adjustment mechanism 15 also places the inner ring 1121 on the supports 1122b by lowering the lift pins 115 below the upper surfaces of the supports 1122b.

[0030] When the inner ring 1121 is worn from its upper surface during plasma processing (e.g., etching processing), the height adjustment mechanism 15 adjusts the height of the upper surface of the inner ring 1121 in accordance with the amount of wear. This corrects the height of the sheath on the inner ring 1121, ensuring uniformity in plasma processing. This also reduces the frequency of replacing the inner ring 1121. The height adjustment mechanism 15 also adjusts the height of the inner ring 1121 to correct the height of the sheath on the inner ring 1121. This allows the angle of incidence of ions on the outer periphery of the substrate W to be adjusted. The height adjustment mechanism 15 can also transfer the inner ring 1121 to a transfer device (not shown) by, for example, raising and lowering the lift pins 115. This allows the worn inner ring 1121 to be removed from the plasma processing chamber 10. The height adjustment mechanism 15 can also receive a new inner ring 1121 carried in by a transfer device (not shown) and place it on the under ring 1122 by, for example, raising and lowering the lift pins 115. In this manner, the inner ring 1121 can be replaced without opening the plasma processing chamber 10 to the atmosphere.

[0031] As shown in FIGS. 3 to 5, the ring assembly 112 includes an edge ring 1120 , a cover ring 1123 , and an insulator ring 1124 .

[0032] The edge ring 1120 includes an inner ring (first annular member) 1121 and an under ring (second annular member) 1122. The inner ring 1121 and the under ring 1122 are made of, for example, SiC, Si, or SiO ２ It is formed from any of the materials listed above.

[0033] The inner ring 1121 is a circular ring-shaped member that is placed on the support portion 1122b of the under ring 1122 and is arranged to surround the substrate W placed on the central region 111a (substrate support surface) of the main body portion 111.

[0034] The under-ring 1122 is a ring-shaped member and is disposed on the annular region 111b (ring support surface) of the main body 111. The under-ring 1122 has, in order from the inside in the radial direction, an inner peripheral side portion 1122a, a support portion 1122b, an outer peripheral side portion 1122c, and a flange portion 1122d, each of which has a different height of the upper surface.

[0035] The inner peripheral side portion 1122a is a portion disposed below the substrate W supported on the central region 111a of the main body 111. The upper surface of the inner peripheral side portion 1122a is formed at a position slightly lower than or at the same height as the substrate support surface (central region 111a) of the electrostatic chuck 1111.

[0036] The support portion 1122b is provided on the outer circumferential side of the inner circumferential side portion 1122a, and the inner ring 1121 is disposed on the support portion 1122b. The upper surface of the support portion 1122b is formed at a position lower than the upper surface of the inner circumferential side portion 1122a.

[0037] The outer peripheral side portion 1122c is provided on the outer peripheral side of the support portion 1122b. The upper surface of the outer peripheral side portion 1122c is formed at a position higher than the upper surfaces of the inner peripheral side portion 1122a and the support portion 1122b. The upper surface of the outer peripheral side portion 1122c is formed at the same height as the upper surface of the cover ring 1123.

[0038] The flange portion 1122d is provided on the outer periphery side of the outer periphery side portion 1122c. The upper surface of the flange portion 1122d is formed at a position lower than the upper surface of the outer periphery side portion 1122c. The inner periphery side of the cover ring 1123 is placed on top of the flange portion 1122d. As a result, the flange portion 1122d of the under ring 1122 is held down by the cover ring 1123, preventing the under ring 1122 from moving upward.

[0039] There is a radial gap between the outer peripheral wall (cylindrical surface) of the inner peripheral side portion 1122a of the under ring 1122 and the inner peripheral wall (cylindrical surface) of the inner ring 1121. In addition, there is a radial gap between the outer peripheral wall (cylindrical surface) of the inner ring 1121 and the inner peripheral wall (cylindrical surface) of the outer peripheral side portion 1122c of the under ring 1122. This prevents the inner ring 1121 and the under ring 1122 from rubbing against each other when the inner ring 1121 is moved up and down. Furthermore, even if a temperature difference occurs between the inner ring 1121 and the under ring 1122 and a thermal expansion difference occurs between the inner ring 1121 and the under ring 1122, the inner ring 1121 and the under ring 1122 will come into contact with each other, preventing damage to the inner ring 1121 and / or the under ring 1122.

[0040] The cover ring 1123 is a ring-shaped member and is disposed so as to surround the edge ring 1120 (under ring 1122). ２ It is formed of insulating materials such as the above.

[0041] The insulator ring 1124 is a ring-shaped member and is disposed so as to surround the main body 111 (the base 1110 and the electrostatic chuck 1111). ２ The insulator ring 1124 supports the cover ring 1123.

[0042] <Positioning Structure of Under-Ring 1122> Next, the structure of the through holes (1111c, 113a, 1122f) through which the lift pins 115 are inserted and the positioning structure of the under-ring 1122 relative to the electrostatic chuck 1111 will be described with reference to FIG. 3 and using FIGS. 6A to 6C and 7A to 7B. FIGS. 6A to 6C are examples of perspective views illustrating the positioning structure of the under-ring 1122. Specifically, FIG. 6A is an example of a perspective view of the under-ring 1122 as viewed from the bottom. FIG. 6B is an example of a perspective view of the cap 113. FIG. 6C is an example of a perspective view of the electrostatic chuck 1111 as viewed from the top.

[0043] 3 and 6C , the electrostatic chuck 1111 has through-holes (first through-holes) 1111c through which the lift pins 115 are inserted. The through-holes 1111c penetrate from the upper surface to the lower surface of the electrostatic chuck 1111. The through-holes 1111c communicate with the through-holes 1110c of the base 1110.

[0044] 3, a cap (cylindrical member) 113 having a through hole (second through hole) 113a is disposed in the through hole 1111c. The cap 113 is made of sapphire, Al ２ O ３ , SiC, etc. Cap 113 is preferably formed of an insulating material to prevent abnormal discharge within through-hole 113a (through-hole 1111c). Cap 113 is preferably formed of a material that is corrosion-resistant, plasma-resistant, and heat-resistant.

[0045] As shown in FIG. 6B , the cap 113 is a cylindrical member having a through-hole 113a penetrating from the top surface to the bottom surface of the cap 113. The lift pins 115 are inserted through the through-hole 113a. The cap 113 also has an upper head (first head) 113b and a lower shaft (first shaft) 113c. The shaft 113c has a circular outer shape in plan view (in other words, when viewed from above, or further in other words, when viewed from a direction perpendicular to the ring support surface of the substrate support portion 11). The shaft 113c is a portion that is inserted into the through-hole 1111c of the electrostatic chuck 1111. The head 113b has a circular outer shape with a larger diameter than the shaft 113c in plan view. The head portion 113 b is a portion that is disposed on the ring support surface (annular region 111 b ) of the electrostatic chuck 1111 when the shaft portion 113 c is inserted into the through-hole 1111 c of the electrostatic chuck 1111 .

[0046] 3 and 6A , the under-ring 1122 has a countersunk portion (first groove portion, first countersunk portion) 1122e and a through-hole (third through-hole) 1122f communicating with the countersunk portion 1122e. The countersunk portion 1122e is formed on the lower surface of the under-ring 1122. When the under-ring 1122 is placed on the ring support surface (annular region 111b) of the electrostatic chuck 1111, the head 113b of the cap 113 is positioned in the countersunk portion 1122e. The through-hole 1122f communicates with the countersunk portion 1122e and penetrates the support portion 1122b of the under-ring 1122 from the lower surface to the upper surface.

[0047] As shown in FIG. 3 , the shaft portion 113c of the cap 113 is inserted into the through-hole 1111c of the electrostatic chuck 1111, and the head portion 113b of the cap 113 is disposed in a counterbore portion 1122e formed in the lower surface of the under-ring 1122, thereby connecting the through-hole 113a of the cap 113 to the through-hole 1122f of the under-ring 1122. The lift pin 115 passes through the through-hole 113a of the cap 113 and the through-hole 1122f of the under-ring 1122 and abuts against the lower surface of the inner ring 1121. A notch 1121a is formed in the lower surface of the inner ring 1121 at a position where the lift pin 115 abuts. The notch 1121a is formed as an elongated hole whose longitudinal direction is the radial direction of the electrostatic chuck 1111. The inner peripheral side of the notch 1121a extends to the inner peripheral wall of the inner ring 1121.

[0048] 7A and 7B are examples of schematic diagrams illustrating a positioning structure for the under-ring 1122. Specifically, Fig. 7A is a schematic plan view of the shape of the countersunk portion 1122e of the under-ring 1122 and the shape of the head 113b of the cap 113 placed in the countersunk portion 1122e. Fig. 7B is a schematic plan view of the shape of the through-hole 1111c of the electrostatic chuck 1111 and the shape of the shaft portion 113c of the cap 113 placed in the through-hole 1111c.

[0049] 7B , the shape (outer periphery) of the shaft portion 113c of the cap 113 is circular. The shape (inner periphery) of the through hole 1111c of the electrostatic chuck 1111 is also circular. The inner diameter of the through hole 1111c is slightly larger than the outer diameter of the shaft portion 113c so that the shaft portion 113c can be inserted into the through hole 1111c. By inserting the shaft portion 113c of the cap 113 into the through hole 1111c of the electrostatic chuck 1111, the axis of the through hole 1111c and the axis of the cap 113 are aligned. That is, the cap 113 is positioned relative to the electrostatic chuck 1111.

[0050] 7A , the head 113b of the cap 113 has a circular shape (outer peripheral shape). In contrast, the countersunk portion 1122e of the under-ring 1122 has an elongated hole shape (slot hole shape) whose longitudinal direction is the radial direction of the electrostatic chuck 1111. Furthermore, the width of the countersunk portion 1122e in the lateral direction is formed slightly larger than the outer diameter of the head 113b so that the head 113b can be placed in the countersunk portion 1122e.

[0051] As shown in FIG. 5 , three positioning structures for the under-ring 1122, including the through-hole 1111c, the cap 113, and the countersunk portion 1122e, are provided at equal intervals in the circumferential direction. In each of the three positioning structures for the under-ring 1122 provided at position S1, the outer peripheral surface of the head 113b of the cap 113 contacts the inner peripheral surface of the countersunk portion 1122e of the under-ring 1122. This positions the under-ring 1122 relative to the electrostatic chuck 1111 at three points. This allows the position of the under-ring 1122 (edge ​​ring 1120) to be adjusted relative to the main body 111 having the electrostatic chuck 1111. That is, the center of the main body 111, which is circular in plan view, and the center of the under-ring 1122, which is annular in plan view, are aligned so as to coincide with each other.

[0052] Furthermore, by making the shape of the recessed portion 1122e an elongated hole with the radial direction of the electrostatic chuck 1111 as the longitudinal direction, it is possible to accommodate the difference in thermal expansion between the electrostatic chuck 1111 and the under-ring 1122.

[0053] <Positioning Structure of Inner Ring 1121> Next, the positioning structure of the inner ring 1121 relative to the under ring 1122 will be described using Figures 8A to 8C and 9A to 9B while referring to Figure 4. Figures 8A to 8C are examples of perspective views illustrating the positioning structure of the inner ring 1121. Specifically, Figure 8A is an example of a perspective view of the inner ring 1121 seen from the bottom. Figure 8B is an example of a perspective view of the under ring 1122 seen from the bottom. Figure 8C is an example of a perspective view of the guide pin 114.

[0054] As shown in FIGS. 4 and 8A, the inner ring 1121 has a groove (second groove) 1121b on the lower surface thereof.

[0055] 4 and 8B , the under-ring 1122 has a countersunk portion (second countersunk portion) 1122g and a through-hole (fourth through-hole) 1122h that communicates with the countersunk portion 1122g. The countersunk portion 1122g is formed on the underside of the under-ring 1122. The head 114a of the guide pin 114 is disposed in the countersunk portion 1122g. The through-hole 1122h communicates with the countersunk portion 1122g and penetrates the support portion 1122b of the under-ring 1122 from the bottom surface to the top surface.

[0056] 4, a guide pin 114 is disposed from the counterbore portion 1122g and the through hole 1122h of the under ring 1122 to the groove portion 1121b of the inner ring 1121. The guide pin 114 is made of sapphire, Al ２ O ３ , SiC, etc. Furthermore, the guide pins 114 are preferably formed of an insulating material to prevent abnormal discharge. Furthermore, the guide pins 114 are preferably formed of a material that is corrosion-resistant, plasma-resistant, and heat-resistant.

[0057] As shown in FIG. 8C , the guide pin 114 is a shaft-shaped member and has a lower head portion (second head portion) 114a and an upper shaft portion (second shaft portion) 114b. The shaft portion 114b has a circular outer shape in plan view. The shaft portion 114b is inserted through the through-hole 1122h of the under ring 1122 and into the groove portion 1121b of the inner ring 1121. The head portion 114a has a circular outer shape with a larger diameter than the shaft portion 114b in plan view. The head portion 114a is disposed in the countersunk portion 1122g of the under ring 1122.

[0058] 9A and 9B are examples of schematic diagrams illustrating the positioning structure of the inner ring 1121. Specifically, Fig. 9A is a schematic diagram illustrating, in plan view, the shape of the groove 1121b of the inner ring 1121 and the shape of the shaft 114b of the guide pin 114 placed in the groove 1121b. Fig. 9B is a schematic diagram illustrating, in plan view, the shape of the counterbore portion 1122g of the under ring 1122 and the shape of the head 114a of the guide pin 114 placed in the counterbore portion 1122g.

[0059] As shown in FIG. 9B , the head 114a of the guide pin 114 has a circular shape (outer periphery). The countersunk portion 1122g of the under-ring 1122 also has a circular shape (inner periphery). The inner diameter of the countersunk portion 1122g is slightly larger than the outer diameter of the head 114a so that the head 114a of the guide pin 114 can be inserted. By inserting the head 114a of the guide pin 114 into the countersunk portion 1122g of the under-ring 1122, the axis of the countersunk portion 1122g and the axis of the guide pin 114 are aligned. In other words, the guide pin 114 is positioned relative to the under-ring 1122.

[0060] 9A , the shape (outer circumferential shape) of the shaft portion 114b of the guide pin 114 is circular. In contrast, the shape (inner circumferential shape) of the groove portion 1121b of the inner ring 1121 is an elongated hole shape (slot hole shape) whose longitudinal direction is the radial direction of the electrostatic chuck 1111. Furthermore, the width of the groove portion 1121b in the lateral direction is formed slightly larger than the outer diameter of the shape of the shaft portion 114b so that the shaft portion 114b can be placed in the groove portion 1121b.

[0061] 5 , three positioning structures for the inner ring 1121, including the guide pin 114, the countersunk portion 1122g and through hole 1122h of the under ring 1122, and the groove 1121b of the inner ring 1121, are provided at equal intervals in the circumferential direction. In each of the three positioning structures for the inner ring 1121 provided at position S2, the outer peripheral surface of the shaft portion 114b of the guide pin 114 contacts the inner peripheral surface of the groove 1121b of the inner ring 1121. This positions the inner ring 1121 relative to the under ring 1122 at three points. Furthermore, the position of the inner ring 1121 can be adjusted relative to the main body 111 having the electrostatic chuck 1111 via the positioned under ring 1122. That is, the center of the under ring 1122, which is annular in plan view, and the center of the inner ring 1121, which is annular in plan view, are aligned so as to coincide with each other. Furthermore, the center of the main body 111, which is circular in plan view, and the center of the inner ring 1121, which is annular in plan view, are aligned to coincide with each other.

[0062] Furthermore, by forming the groove portion 1121 b in the shape of an elongated hole with the radial direction of the electrostatic chuck 1111 as the longitudinal direction, it is possible to accommodate the difference in thermal expansion between the inner ring 1121 and the under ring 1122 .

[0063] As described above, the substrate support part 11 according to the first embodiment can prevent the edge ring 1120 (the inner ring 1121 and the under ring 1122) from becoming misaligned due to thermal expansion caused by heat input during substrate processing. Furthermore, preventing the edge ring 1120 from becoming misaligned improves the stability of the substrate processing process.

[0064] Furthermore, if there is a potential difference between the inner ring 1121 and the under ring 1122 that are lifted by the lift pins 115, abnormal discharge may occur due to contact between the inner ring 1121 and the under ring 1122. In contrast, with the substrate support part 11 according to the first embodiment, the occurrence of abnormal discharge can be suppressed by suppressing misalignment of the edge ring 1120.

[0065] Next, the substrate support part 11 according to the second embodiment will be further described with reference to FIGS. 10 to 11D.

[0066] In the substrate support part 11 according to the second embodiment, the positioning structure of the under-ring 1122 has the same structure as the positioning structure of the under-ring 1122 in the substrate support part 11 according to the first embodiment (see FIGS. 3, 6, and 7). Furthermore, the substrate support part 11 according to the second embodiment has a different positioning structure for the inner ring 1121. Therefore, the following will describe the positioning structure of the inner ring 1121 of the substrate support part 11 according to the second embodiment, and will omit descriptions that overlap with those of the substrate support part 11 according to the first embodiment.

[0067] FIG. 10 is another example of an enlarged cross-sectional view of the substrate support portion 11 according to the second embodiment. FIGS. 11A to 11D are examples of diagrams illustrating a positioning structure for the inner ring 1121. Note that FIG. 10 is a cross-sectional view of the substrate support portion 11 cut radially, with the left side of the drawing corresponding to the center of the substrate support portion 11 and the right side of the drawing corresponding to the outer periphery of the substrate support portion 11. FIG. 10 is a cross-sectional view of position S2 (the position indicated by the black circle in FIG. 5 ) where the positioning structure for the inner ring 1121 is provided. Specifically, FIG. 11A is a schematic cross-sectional view of the inner ring 1121 and the under ring 1122 cut radially. FIG. 11B is a view of the under ring 1122 as viewed from above. FIG. 11C is a perspective view of the under ring 1122 as viewed from above. FIG. 11D is a perspective view of the inner ring 1121 as viewed from the bottom.

[0068] 10 , a convex portion (first convex portion) 1122i is formed on the upper surface of the support portion 1122b of the under-ring 1122. In addition, a groove portion (third groove portion) 1121c is formed on the lower surface of the inner ring 1121. The lower surface of the inner ring 1121 abuts against the upper surface of the support portion 1122b of the under-ring 1122. The convex portion 1122i is disposed within the groove portion 1121c.

[0069] As shown in FIGS. 11A to 11C, the convex portion 1122i has a spherical shape.

[0070] 11A, the groove 1121c has an arc-shaped cross section when viewed in the radial direction. The radius of curvature of the arc shape of the groove 1121c is larger than the radius of curvature of the spherical surface of the convex portion 1122i. Furthermore, as shown in FIGS. 11B to 11D, the groove 1121c is formed as an elongated hole whose longitudinal direction is the radial direction of the electrostatic chuck 1111.

[0071] Here, in the positioning structure for the inner ring 1121 provided at position S2, the convex portion 1122i of the under ring 1122 and the groove portion 1121c of the inner ring 1121 contact each other at one point. FIG. 11A shows an example of contact point P1. As shown in FIG. 5, the positioning structure for the inner ring 1121, including the convex portion 1122i and the groove portion 1121c, is provided at three locations equally spaced circumferentially. This positions the inner ring 1121 relative to the under ring 1122 at three points. Furthermore, the position of the inner ring 1121 can be adjusted relative to the main body 111 having the electrostatic chuck 1111 via the positioned under ring 1122. That is, the center of the under ring 1122, which is annular in plan view, and the center of the inner ring 1121, which is annular in plan view, are aligned so as to coincide with each other. Furthermore, the center of the main body 111, which is circular in plan view, and the center of the inner ring 1121, which is annular in plan view, are aligned to coincide with each other.

[0072] Furthermore, by forming the groove portion 1121 c in the shape of an elongated hole with the radial direction of the electrostatic chuck 1111 as the longitudinal direction, it is possible to accommodate the difference in thermal expansion between the inner ring 1121 and the under ring 1122 .

[0073] As described above, the substrate support part 11 according to the second embodiment can prevent the edge ring 1120 (the inner ring 1121 and the under ring 1122) from becoming misaligned due to thermal expansion caused by heat input during substrate processing. Furthermore, preventing the edge ring 1120 from becoming misaligned improves the stability of the substrate processing process.

[0074] Furthermore, if there is a potential difference between the inner ring 1121 and the under ring 1122 that are lifted by the lift pins 115, abnormal discharge may occur due to contact between the inner ring 1121 and the under ring 1122. In contrast, with the substrate support part 11 according to the second embodiment, the occurrence of abnormal discharge can be suppressed by suppressing misalignment of the edge ring 1120.

[0075] Furthermore, when the inner ring 1121 lifted by the lift pins 115 is lowered and placed on the support portion 1122b of the under ring 1122, the convex portion 1122i of the under ring 1122 enters the groove portion 1121c of the inner ring 1121, and the convex portion 1122i and the groove portion 1121c come into contact with each other, thereby adjusting the center position. As a result, even if the inner ring 1121 lifted by the lift pins 115 becomes misaligned due to thermal expansion or the like, the center position can be adjusted by lowering the inner ring 1121 and placing it on the support portion 1122b of the under ring 1122.

[0076] The convex portion 1122i and the groove portion 1121c are configured to contact each other at a single contact point P1, thereby ensuring that the lower surface of the inner ring 1121 and the upper surface of the support portion 1122b of the under ring 1122 are in contact with each other.

[0077] 11A, the groove 1121c formed in the inner ring 1121 has an arc-shaped cross section when viewed in the radial direction, but is not limited to this. Figures 12A and 12B are diagrams illustrating another example of the positioning structure of the inner ring 1121.

[0078] 12A, the groove 1121c may have an inverted V-shaped cross section when viewed in the radial direction. The protrusion 1122i and the groove 1121c are configured to contact each other at a single contact point P2. This ensures that the lower surface of the inner ring 1121 and the upper surface of the support portion 1122b of the under-ring 1122 are in contact with each other.

[0079] 12B, the groove 1121c may be configured so that its cross section has an inverted V-shape when viewed in the radial direction, and the protrusion 1122i and the groove 1121c come into contact with each other at two contact points P31 and P32. That is, the three protrusions 1122i formed on the under ring 1122 and the three grooves 1121c formed on the inner ring 1121 come into contact with each other at a total of six contact points. This forms a kinematic coupling, further improving the positioning accuracy of the inner ring 1121 relative to the under ring 1122.

[0080] Although not shown, the groove 1121c may be configured so that its cross section is arc-shaped when viewed in the radial direction, and the protrusions 1122i and the groove 1121c come into contact with each other at two contact points. That is, the three protrusions 1122i formed on the under ring 1122 and the three grooves 1121c formed on the inner ring 1121 come into contact with each other at a total of six contact points. This forms a kinematic coupling, further improving the positioning accuracy of the inner ring 1121 relative to the under ring 1122.

[0081] 10 , the substrate support member 11 according to the second embodiment has a positioning structure for the cover ring 1123 that positions the cover ring 1123 relative to the under ring 1122. The positioning structure for the cover ring 1123 includes a groove (fourth groove) 1122j provided on the upper surface of the flange portion 1122d of the under ring 1122 and a convex portion (second convex portion) 1123a provided on the lower surface of the inner circumferential side (the portion disposed above the flange portion 1122d) of the cover ring 1123. Like the convex portion 1122i, the convex portion 1123a has a spherical shape. Like the groove portion 1121c, the groove portion 1122j has an arc-shaped or inverted V-shaped cross section when viewed in the radial direction of the electrostatic chuck 1111, and is an elongated hole with its longitudinal direction aligned with the radial direction of the electrostatic chuck 1111. Alternatively, a convex portion may be provided on the upper surface of the flange portion 1122d of the under ring 1122, and a groove portion may be provided on the lower surface of the inner periphery of the cover ring 1123.

[0082] Furthermore, the positioning structure of the cover ring 1123 shown in FIG. 10 may be applied to the substrate support part 11 according to the first embodiment shown in FIG. 3 and the like.

[0083] The embodiments disclosed above include, for example, the following aspects: (Supplementary Note 1) A substrate processing apparatus comprising: an electrostatic chuck having a substrate support surface and a ring support surface, the ring support surface having first through holes through which lift pins are inserted; an edge ring supported on the ring support surface; and a tubular member inserted into the first through hole of the electrostatic chuck and having a second through hole, wherein the tubular member has: a first shank inserted into the first through hole of the electrostatic chuck; and a first head portion that is a portion disposed above the ring support surface of the electrostatic chuck when the first shank is inserted into the first through hole of the electrostatic chuck, and the edge ring has a first groove portion provided on a lower surface of the edge ring and in which the first head portion is disposed. (Supplementary Note 2) The substrate processing apparatus according to Supplementary Note 1, wherein the first groove portion is an elongated hole whose longitudinal direction is the radial direction of the electrostatic chuck. (Supplementary Note 3) The substrate processing apparatus according to Supplementary Note 1 or Supplementary Note 2, wherein the first head portion has a larger diameter than the first shank portion. (Supplementary Note 4) The substrate processing apparatus according to any one of Supplementary Notes 1 to 3, wherein the first through holes of the electrostatic chuck, the cylindrical member inserted into the first through holes, and the first groove portions of the edge ring are each provided in threes in a circumferential direction. (Supplementary Note 5) The substrate processing apparatus according to any one of Supplementary Notes 1 to 4, wherein the edge ring has an under ring supported by the ring support surface and an inner ring disposed on the under ring, and the under ring has a first counterbore portion which is the first groove portion, and a third through hole which communicates with the first counterbore portion, penetrates from a lower surface to an upper surface of the under ring, and communicates with the second through hole of the cylindrical member so that the lift pin can be inserted therethrough. (Appendix 6) A substrate processing apparatus as described in Appendix 5, further comprising a guide pin having a second shaft portion and a second head portion having a diameter larger than that of the second shaft portion, wherein the under ring has: a second countersunk portion provided on the under surface of the under ring and in which the second head portion is disposed; and a fourth through hole communicating with the second countersunk portion, penetrating from the lower surface to the upper surface of the under ring, and through which the second shaft portion is inserted, and wherein the inner ring has a second groove portion provided on the under surface of the inner ring and in which the second shaft portion protruding from the under ring is disposed.(Supplementary Note 7) The substrate processing apparatus according to Supplementary Note 6, wherein the second groove portion is an elongated hole having a longitudinal direction in the radial direction of the electrostatic chuck. (Supplementary Note 8) The substrate processing apparatus according to Supplementary Note 6 or Supplementary Note 7, wherein the guide pin, the second countersunk portion and the fourth through hole of the under ring, and the second groove portion of the inner ring are provided in sets of three each in the circumferential direction. (Supplementary Note 9) The substrate processing apparatus according to Supplementary Note 5, wherein the under ring has a convex portion, and the inner ring has a third groove portion provided on a lower surface of the inner ring and in which the convex portion of the under ring is disposed. (Supplementary Note 10) The substrate processing apparatus according to Supplementary Note 9, wherein the convex portion has a spherical shape, and the third groove portion is an elongated hole having an arc-shaped cross section as viewed in the radial direction of the electrostatic chuck and having a longitudinal direction in the radial direction of the electrostatic chuck. (Supplementary Note 11) The substrate processing apparatus according to Supplementary Note 9, wherein the convex portion has a spherical shape, and the third groove portion is an elongated hole having an inverted V-shaped cross section when viewed in the radial direction of the electrostatic chuck, and whose longitudinal direction is the radial direction of the electrostatic chuck. (Supplementary Note 12) The substrate processing apparatus according to Supplementary Note 10 or Supplementary Note 11, wherein the convex portion contacts the third groove portion at one point. (Supplementary Note 13) The substrate processing apparatus according to Supplementary Note 10 or Supplementary Note 11, wherein the convex portion contacts the third groove portion at two points. (Supplementary Note 14) The substrate processing apparatus according to any of Supplementary Notes 9 to 13, wherein three convex portions and three third groove portions are provided in the circumferential direction. (Appendix 15) A substrate processing apparatus as described in any of Appendices 9 to 14, further comprising a cover ring surrounding the edge ring, wherein one of the under ring and the cover ring has a second convex portion, and the other of the under ring and the cover ring has a fourth groove portion in which the second convex portion is arranged.

[0084] The above describes embodiments of the plasma processing system, but the present disclosure is not limited to the above embodiments, and various modifications and improvements are possible within the scope of the gist of the present disclosure as described in the claims.

[0085] This application claims priority based on Japanese Patent Application No. 2023-123714, filed on July 28, 2023, the entire contents of which are incorporated herein by reference.

[0086] REFERENCE SIGNS LIST W substrate 1 plasma processing apparatus 2 control unit 11 substrate support unit 15 height adjustment mechanism 111 main body unit 111a central region 111b annular region 112 ring assembly 113 cap (cylindrical member) 113a through hole (second through hole) 113b head (first head) 113c shaft (first shaft) 114 guide pin 114a head (second head) 114b shaft (second shaft) 115 lift pin 1110 base 1111 electrostatic chuck 1111c through hole (first through hole) 1120 edge ring 1121 inner ring (first annular member) 1121a cutout portion 1121b groove (second groove) 1121c groove (third groove) 1122 Under ring (second annular member) 1122a Inner peripheral side portion 1122b Support portion 1122c Outer peripheral side portion 1122d Flange portion 1122e Counterbore portion (first groove portion, first counterbore portion) 1122f Through hole (third through hole) 1122g Counterbore portion (second counterbore portion) 1122h Through hole (fourth through hole) 1122i Convex portion (first convex portion) 1122j Groove portion (fourth groove portion) 1123 Cover ring 1123a Convex portion (second convex portion) 1124 Insulator ring

Claims

1. A substrate processing apparatus comprising: an electrostatic chuck having a substrate support surface and a ring support surface, the ring support surface having a first through hole through which a lift pin is inserted; an edge ring supported on the ring support surface; and a cylindrical member having a second through hole and inserted into the first through hole of the electrostatic chuck, the cylindrical member having a first shaft portion inserted into the first through hole of the electrostatic chuck, and a first head portion that is positioned on the ring support surface of the electrostatic chuck when the first shaft portion is inserted into the first through hole of the electrostatic chuck, the edge ring having a first groove portion provided on an underside of the edge ring and in which the first head portion is positioned.

2. The substrate processing apparatus according to claim 1, wherein the first groove portion is an elongated hole whose longitudinal direction is the radial direction of the electrostatic chuck.

3. The substrate processing apparatus according to claim 1, wherein the first head portion has a larger diameter than the first shaft portion.

4. The substrate processing apparatus according to claim 1, wherein the first through hole of the electrostatic chuck, the cylindrical member inserted into the first through hole, and the first groove portion of the edge ring are provided in threes in the circumferential direction.

5. The substrate processing apparatus of claim 1, wherein the edge ring has an under-ring supported by the ring support surface and an inner ring arranged on the under-ring, and the under-ring has a first countersunk portion which is the first groove portion, and a third through hole which communicates with the first countersunk portion, penetrates from the lower surface to the upper surface of the under-ring, and communicates with the second through hole of the cylindrical member so that the lift pin can be inserted.

6. A substrate processing apparatus as described in claim 5, further comprising a guide pin having a second shaft portion and a second head portion having a diameter larger than that of the second shaft portion, wherein the underring has a second countersunk portion provided on the underring's underside and in which the second head portion is disposed, and a fourth through hole communicating with the second countersunk portion, penetrating from the underring's underside to its top surface and through which the second shaft portion is inserted, and wherein the inner ring has a second groove portion provided on the underring's underside and in which the second shaft portion protruding from the underring is disposed.

7. The substrate processing apparatus according to claim 6, wherein the second groove portion is an elongated hole whose longitudinal direction is the radial direction of the electrostatic chuck.

8. The substrate processing apparatus according to claim 6, wherein the guide pins, the second countersunk portion and the fourth through hole of the under ring, and the second groove portion of the inner ring are provided in threes each in the circumferential direction.

9. The substrate processing apparatus according to claim 5, wherein the under ring has a first convex portion, and the inner ring has a third groove portion provided on the underside of the inner ring and in which the first convex portion of the under ring is disposed.

10. The substrate processing apparatus according to claim 9, wherein the first convex portion has a spherical shape, and the third groove portion has an arc-shaped cross section when viewed in the radial direction of the electrostatic chuck, and is an elongated hole whose longitudinal direction is the radial direction of the electrostatic chuck.

11. The substrate processing apparatus according to claim 9, wherein the first convex portion has a spherical shape, and the third groove portion has an inverted V-shaped cross section when viewed in the radial direction of the electrostatic chuck, and is an elongated hole whose longitudinal direction is the radial direction of the electrostatic chuck.

12. The substrate processing apparatus according to claim 10 or 11, wherein the first convex portion contacts the third groove portion at one point.

13. The substrate processing apparatus according to claim 10 or 11, wherein the first convex portion contacts the third groove portion at two points.

14. The substrate processing apparatus according to claim 9, wherein the first convex portions and the third groove portions are provided in threes in the circumferential direction.

15. The substrate processing apparatus of claim 9, further comprising a cover ring surrounding the edge ring, wherein one of the under ring and the cover ring has a second convex portion, and the other of the under ring and the cover ring has a fourth groove portion in which the second convex portion is disposed.

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