Substrate support base, plasma processing system, and mounting method for annular member

Abstract

To provide a substrate support base for positioning and appropriately placing an annular member on a placement surface with respect to the annular member regardless of transfer accuracy of the annular member, a plasma processing system and a mounting method for an annular member.SOLUTION: In a plasma processing system, a substrate support base 101 comprises: a substrate placement surface 104a on which a wafer W is placed; an annular member placement surface 104b on which an edge ring F is placed, the edge ring being an annular member to be disposed so as to enclose the wafer held on the substrate placement surface; three or more lift pins 107 which can protrude from the annular member placement surface and are lifted so as to freely adjust a protrusion amount from the annular member placement surface; and a lift mechanism which lifts the lift pins. The edge ring is positioned with respect to the lift pins 107 and the list pins are provided with high accuracy with respect to a center of an electrostatic chuck 104, such that the wafer is placed on the substrate placement surface while being positioned with respect to the center of the electrostatic chuck.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a substrate support pedestal, a plasma processing system, and a method for mounting an annular member. [Background technology]

[0002] Patent Document 1 discloses a substrate processing apparatus in which a substrate is placed in a processing chamber, a focus ring is placed so as to surround the periphery of the substrate, and plasma processing is performed on the substrate. This substrate processing apparatus includes a mounting table equipped with a susceptor having a substrate mounting surface on which a substrate is placed and a focus ring mounting surface on which a focus ring is placed, and a plurality of positioning pins. The positioning pins are formed in a pin shape using a material that expands radially when heated, and are attached to the focus ring so as to protrude from its lower surface and are inserted into positioning holes formed on the focus ring mounting surface of the susceptor, and are fitted into the focus ring by expanding radially when heated. The substrate processing apparatus disclosed in Patent Document 1 also includes a lifter pin and a transport arm. The lifter pins are provided on the mounting table so as to protrude and retract from the focus ring mounting surface, and lift the focus ring together with the positioning pins to detach it from the focus ring mounting surface. The transport arm is provided outside the processing chamber, and transfers the focus ring with the positioning pins attached between the lifter pins and the focus ring through a transfer port provided in the processing chamber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-54933 A Summary of the Invention [Problem to be solved by the invention]

[0004] The technique according to the present disclosure positions and appropriately places an annular member on a mounting surface of a substrate support table that is adapted to support the annular member. [Means for solving the problem]

[0005] One aspect of the present disclosure is a substrate support table having a substrate mounting surface on which a substrate is mounted, an annular member mounting surface on which an annular member arranged to surround a substrate held on the substrate mounting surface is mounted, three or more lifters configured to be protruding from the annular member mounting surface and raised and lowered so as to freely adjust the amount of protrusion from the annular member mounting surface, and a lifting mechanism for raising and lowering the lifters, and the annular member has an upwardly recessed portion at a position on a bottom surface of the annular member corresponding to each of the lifters. Mukon a recess is provided, and in a planar view, the recess is larger than the transport accuracy of the annular member above the annular member mounting surface and is larger than the upper end of the lifter, the upper end of the lifter is formed to gradually become narrower toward the top, and the recess is formed to gradually become narrower toward the top, the annular member is both an edge ring arranged adjacent to a substrate placed on the substrate mounting surface and a covering ring covering the outer surface of the edge ring, and of the edge ring and the covering ring, the recess is formed in a bottom surface of the edge ring, and the covering ring has a through hole leading to the recess of the edge ring through which the lifter is inserted, and the lifter has an edge ring support portion at its upper end that engages with the recess of the edge ring and supports the edge ring, and has a covering ring support portion below the edge ring support portion. Effect of the Invention

[0006] According to the present disclosure, the annular member can be positioned and appropriately placed on the support surface of the substrate support table for the annular member. [Brief description of the drawings]

[0007] [Figure 1] 1 is a plan view showing an outline of a configuration of a plasma processing system in accordance with a first embodiment. [Diagram 2] 2 is a longitudinal sectional view showing the outline of the configuration of the processing module of FIG. 1. [Diagram 3]FIG. 3 is a partially enlarged view of FIG. [Figure 4] 3 is a partial cross-sectional view of a portion different from FIG. 2 in the circumferential direction of the wafer support table. [Diagram 5] 11A and 11B are diagrams illustrating the state inside a processing module during an edge ring attachment process. [Figure 6] 11A and 11B are diagrams illustrating the state inside a processing module during an edge ring attachment process. [Figure 7] 11A and 11B are diagrams illustrating the state inside a processing module during an edge ring attachment process. [Figure 8] 13A and 13B are diagrams for explaining other examples of lift pins. [Figure 9] 11A and 11B are diagrams for explaining another example of an electrostatic chuck. [Figure 10] 11 is a partially enlarged cross-sectional view showing the outline of the configuration of a wafer support stage serving as a substrate support stage in accordance with a second embodiment. FIG. [Figure 11] 11 is a partially enlarged cross-sectional view showing the outline of the configuration of a wafer support stage serving as a substrate support stage in accordance with a third embodiment. FIG. [Figure 12] 13 is a partially enlarged cross-sectional view showing the outline of the configuration of a wafer support stage serving as a substrate support stage in accordance with a fourth embodiment. FIG. [Figure 13] 13 is a diagram showing a schematic diagram of the state inside the processing module during the edge ring removal process of FIG. 12. [Figure 14] 13 is a diagram showing a schematic diagram of the state inside the processing module during the edge ring removal process of FIG. 12. [Figure 15] 13 is a diagram showing a schematic diagram of the state inside the processing module during the edge ring removal process of FIG. 12. [Figure 16] 13 is a diagram showing a schematic diagram of the state inside the processing module during the edge ring removal process of FIG. 12. [Figure 17] 13 is a diagram showing a schematic diagram of the state inside the processing module during the edge ring removal process of FIG. 12. [Figure 18] 13 is a diagram showing a schematic diagram of the state inside the processing module during the edge ring removal process of FIG. 12. [Figure 19] 13 is a partially enlarged cross-sectional view showing the outline of the configuration of a wafer support stage serving as a substrate support stage in accordance with a fifth embodiment. FIG. [Figure 20] 13A and 13B are diagrams showing modified examples of an edge ring and a cover ring. [Figure 21] 13A and 13B are diagrams showing other modified examples of the edge ring and the cover ring. [Figure 22] 20 shows the surroundings of the wafer support pedestal of FIG. 19 during the process of attaching both the edge ring and the cover ring. [Diagram 23] 20 shows the surroundings of the wafer support pedestal of FIG. 19 during the process of attaching both the edge ring and the cover ring. [Figure 24] 20 shows the surroundings of the wafer support pedestal of FIG. 19 during the process of attaching both the edge ring and the cover ring. [Diagram 25] 20 is a diagram showing the state around the wafer support table in FIG. 19 during the process of removing the edge ring alone. [Figure 26] 20 is a diagram showing the state around the wafer support table in FIG. 19 during the process of removing the edge ring alone. [Figure 27] 20 is a diagram showing the state around the wafer support table in FIG. 19 during the process of removing the edge ring alone. [Figure 28] 20 is a diagram showing the state of the periphery of the wafer support table in FIG. 19 during the process of removing the cover ring alone. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] In a manufacturing process for semiconductor devices, etc., plasma processing such as etching and film formation is performed on a substrate such as a semiconductor wafer (hereinafter referred to as "wafer") using plasma. The plasma processing is performed in a state where the wafer is held on a substrate support table provided in a processing chamber configured to be able to reduce pressure.

[0009] In addition, in order to obtain good and uniform processing results at the center and periphery of the substrate during plasma processing, an annular member called an edge ring or a focus ring may be arranged to surround the periphery of the substrate on the substrate support table. When an edge ring is used, the edge ring is positioned with high precision so that uniform processing results can be obtained in the circumferential direction at the periphery of the substrate. For example, in Patent Document 1, the edge ring is positioned using a positioning pin that is attached to the edge ring so as to protrude from its lower surface and is inserted into a positioning hole formed in the edge ring mounting surface.

[0010] When an edge ring becomes worn, it is generally replaced by an operator, but it is also considered to use a transfer device to transfer the edge ring for replacement. For example, in Patent Document 1, the edge ring is replaced using lifter pins that are provided so as to protrude from and retract from the edge ring mounting surface of the mounting table and lift the edge ring to detach it from the edge ring mounting surface, and a transfer arm that can transfer both the wafer and the edge ring into and out of the processing chamber.

[0011] However, when replacing the edge ring using a transport device, if the transport accuracy of the edge ring is poor, a part of the edge ring may get caught on the substrate mounting surface of the substrate support stand, making it impossible to properly mount the edge ring on the edge ring mounting surface of the substrate support stand. For example, if the difference between the inner diameter of the edge ring and the diameter of the substrate mounting surface is smaller than the transport accuracy (transport error) of the edge ring, and the position of the substrate mounting surface is higher than the position of the edge ring mounting surface, the inner side of the edge ring may get caught on the substrate mounting surface, making it impossible to mount the edge ring on the edge ring mounting surface.

[0012] In addition, during plasma processing, an annular member called a cover ring may be disposed to cover the outer peripheral surface of the edge ring. In this case, if a transport device is used to replace the cover ring, the cover ring may not be placed accurately on the mounting surface for the cover ring.

[0013] Therefore, the technique according to the present disclosure positions and appropriately places the annular member on the mounting surface of the substrate support table for the annular member, regardless of the accuracy with which the annular member is transported.

[0014] Hereinafter, a substrate support table, a plasma processing system, and an edge ring replacement method according to the present embodiment will be described with reference to the drawings. In this specification and the drawings, elements having substantially the same functional configurations are designated by the same reference numerals, and duplicated descriptions will be omitted.

[0015] (First embodiment) FIG. 1 is a plan view showing an outline of the configuration of a plasma processing system in accordance with the first embodiment. In the plasma processing system 1 of FIG. 1, plasma processing such as etching, film formation, diffusion, etc. is performed on a wafer W as a substrate by using plasma.

[0016] 1, the plasma processing system 1 has an atmospheric section 10 and a reduced pressure section 11, which are connected together via load lock modules 20 and 21. The atmospheric section 10 includes an atmospheric module that performs a desired process on a wafer W in an atmospheric pressure atmosphere. The reduced pressure section 11 includes a reduced pressure module that performs a desired process on a wafer W in a reduced pressure atmosphere.

[0017] The load lock modules 20, 21 are provided to connect a loader module 30 (described later) in the atmospheric section 10 and a transfer module 50 (described later) in the reduced pressure section 11 via a gate valve (not shown). The load lock modules 20, 21 are configured to temporarily hold a wafer W. The load lock modules 20, 21 are also configured so that the interior thereof can be switched between an atmospheric pressure atmosphere and a reduced pressure atmosphere (vacuum state).

[0018] The atmospheric section 10 has a loader module 30 equipped with a transfer device 40, which will be described later, and a load port 32 on which FOUPs 31a and 31b are placed. FOUP 31a is capable of storing a plurality of wafers W, and FOUP 31b is capable of storing a plurality of edge rings F. Note that an orienter module (not shown) for adjusting the horizontal orientation of the wafers W and edge rings F, a storage module (not shown) for storing a plurality of wafers W, and the like may be provided adjacent to the loader module 30.

[0019] The loader module 30 is made up of a rectangular housing, and the inside of the housing is maintained at atmospheric pressure. A plurality of, for example, five load ports 32 are arranged side by side on one side constituting the long side of the housing of the loader module 30. The load lock modules 20 and 21 are arranged side by side on the other side constituting the long side of the housing of the loader module 30.

[0020] A transfer device 40 for transferring the wafer W or the edge ring F is provided inside the loader module 30. The transfer device 40 has a transfer arm 41 that moves while supporting the wafer W or the edge ring F, a rotating table 42 that rotatably supports the transfer arm 41, and a base 43 on which the rotating table 42 is mounted. A guide rail 44 extending in the longitudinal direction of the loader module 30 is provided inside the loader module 30. The base 43 is provided on the guide rail 44, and the transfer device 40 is configured to be movable along the guide rail 44.

[0021] The depressurization section 11 has a transfer module 50 for transporting the wafer W and the edge ring F, and a processing module 60 serving as a plasma processing apparatus for performing a desired plasma processing on the wafer W transported from the transfer module 50. The interiors of the transfer module 50 and the processing module 60 are each maintained in a reduced pressure atmosphere. A plurality of processing modules 60, for example, eight processing modules 60, are provided for one transfer module 50. Note that the number and arrangement of the processing modules 60 are not limited to those in this embodiment and can be set arbitrarily, and it is sufficient that at least one processing module that requires replacement of the edge ring F is provided.

[0022] The transfer module 50 is made of a housing having a polygonal shape (pentagonal shape in the illustrated example) inside, and is connected to the load lock modules 20 and 21 as described above. The transfer module 50 transports the wafer W loaded into the load lock module 20 to one of the processing modules 60, and also transports the wafer W that has been subjected to the desired plasma processing in the processing module 60 to the atmospheric section 10 via the load lock module 21. The transfer module 50 also transports the edge ring F loaded into the load lock module 20 to one of the processing modules 60, and also transports the edge ring F to be replaced in the processing module 60 to the atmospheric section 10 via the load lock module 21.

[0023] The processing module 60 performs plasma processing such as etching, film formation, and diffusion using plasma on the wafer W. The processing module 60 can be selected arbitrarily as a module for performing a desired plasma processing. The processing module 60 is connected to the transfer module 50 via a gate valve 61. The configuration of the processing module 60 will be described later.

[0024] A transfer device 70 for transferring the wafer W and the edge ring F is provided inside the transfer module 50. The transfer device 70 has a transfer arm 71 as a support part that supports and moves the wafer W and the edge ring F, a rotating table 72 that rotatably supports the transfer arm 71, and a base 73 on which the rotating table 72 is mounted. In addition, a guide rail 74 extending in the longitudinal direction of the transfer module 50 is provided inside the transfer module 50. The base 73 is provided on the guide rail 74, and the transfer device 70 is configured to be movable along the guide rail 74.

[0025] In the transfer module 50, the transfer arm 71 receives the wafer W and edge ring F held in the load lock module 20 and carries them into the processing module 60. Also, the transfer arm 71 receives the wafer W and edge ring F held in the processing module 60 and carries them out to the load lock module 21.

[0026] The plasma processing system 1 further includes a controller 80. In one embodiment, the controller 80 processes computer-executable instructions that cause the plasma processing system 1 to perform various operations described in this disclosure. The controller 80 may be configured to control each of the other elements of the plasma processing system 1 to perform various operations described herein. In one embodiment, some or all of the controller 80 may be included in the other elements of the plasma processing system 1. The controller 80 may include, for example, a computer 90. The computer 90 may include, for example, a processor (CPU: Central Processing Unit) 91, a storage unit 92, and a communication interface 93. The processor 91 may be configured to perform various control operations based on programs stored in the storage unit 92. The storage unit 92 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 93 may communicate with the other elements of the plasma processing system 1 via a communication line such as a local area network (LAN).

[0027] Next, a wafer processing performed using the plasma processing system 1 configured as above will be described.

[0028] First, the transfer device 40 removes the wafer W from the desired FOUP 31a and loads it into the load lock module 20. When the wafer W is loaded into the load lock module 20, the inside of the load lock module 20 is sealed and depressurized. Then, the inside of the load lock module 20 and the inside of the transfer module 50 are connected to each other.

[0029] Next, the wafer W is held by the transfer device 70 and transferred from the load lock module 20 to the transfer module 50 .

[0030] Next, the gate valve 61 is opened, and the wafer W is loaded into a desired processing module 60 by the transfer device 70. Thereafter, the gate valve 61 is closed, and a desired processing is performed on the wafer W in the processing module 60. The processing performed on the wafer W in the processing module 60 will be described later.

[0031] Next, the gate valve 61 is opened, and the wafer W is unloaded from the processing module 60 by the transfer device 70. Thereafter, the gate valve 61 is closed.

[0032] Next, the wafer W is loaded into the load lock module 21 by the transfer device 70. When the wafer W is loaded into the load lock module 21, the inside of the load lock module 21 is sealed and opened to the atmosphere. Thereafter, the inside of the load lock module 21 and the inside of the loader module 30 are communicated with each other.

[0033] Next, the wafer W is held by the transfer device 40, and is returned from the load lock module 21 through the loader module 30 to the desired FOUP 31a and accommodated therein. This completes a series of wafer processing steps in the plasma processing system 1.

[0034] In addition, when replacing the edge ring, the transport of the edge ring between FOUP 31b and the desired processing module 60 is performed in the same manner as the transport of the wafer between FOUP 31a and the desired processing module 60 during the above-mentioned wafer processing.

[0035] Next, the processing module 60 will be described with reference to Figs. 2 to 4. Fig. 2 is a vertical cross-sectional view showing an outline of the configuration of the processing module 60. Fig. 3 is a partially enlarged view of Fig. 2. Fig. 4 is a partial cross-sectional view of a portion different from Fig. 2 in the circumferential direction of a wafer support table 101 described later.

[0036] 2, the processing module 60 includes a plasma processing chamber 100 as a processing container, a gas supply unit 130, an RF (Radio Frequency) power supply unit 140, and an exhaust system 150. The processing module 60 also includes a gas supply unit 120 (see FIG. 4), which will be described later. The processing module 60 further includes a wafer support pedestal 101 as a substrate support pedestal, and an upper electrode showerhead 102.

[0037] The wafer support pedestal 101 is disposed in a lower region of a plasma processing space 100s in a plasma processing chamber 100 that is configured to be depressurized. The upper electrode showerhead 102 is disposed above the wafer support pedestal 101 and can function as a part of the ceiling of the plasma processing chamber 100.

[0038] The wafer support 101 is configured to support a wafer W in the plasma processing space 100s. In one embodiment, the wafer support 101 includes a lower electrode 103, an electrostatic chuck 104, an insulator 105, lift pins 106, and lift pins 107 as a lifter. Although not shown, in one embodiment, the wafer support 101 may include a temperature adjustment module configured to adjust at least one of the electrostatic chuck 104 and the wafer W to a target temperature. The temperature adjustment module may include a heater, a flow path, or a combination thereof. A temperature adjustment fluid such as a coolant or a heat transfer gas flows through the flow path.

[0039] The lower electrode 103 is made of a conductive material such as aluminum. In one embodiment, the temperature control module described above may be provided in the lower electrode 103.

[0040] The electrostatic chuck 104 is a member configured to be able to attract and hold both the wafer W and the edge ring F by electrostatic force, and is provided on the lower electrode 103. The electrostatic chuck 104 is formed such that the upper surface of the central portion is higher than the upper surface of the peripheral portion. The upper surface 104a of the central portion of the electrostatic chuck 104 serves as a substrate mounting surface on which the wafer W is mounted, and the upper surface 104b of the peripheral portion of the electrostatic chuck 104 serves as an annular member mounting surface on which the edge ring F as an annular member is mounted. The edge ring F is an annular member disposed so as to surround the wafer W mounted on the upper surface 104a of the central portion of the electrostatic chuck 104.

[0041] An electrode 108 for attracting and holding the wafer W is provided in the center of the electrostatic chuck 104, and an electrode 109 for attracting and holding the edge ring F is provided on the periphery of the electrostatic chuck 104. The electrostatic chuck 104 has a configuration in which the electrodes 108 and 109 are sandwiched between insulating materials made of an insulating material.

[0042] A DC voltage is applied to the electrode 108 from a DC power supply (not shown). The resulting electrostatic force attracts and holds the wafer W on the upper surface 104a at the center of the electrostatic chuck 104. Similarly, a DC voltage is applied to the electrode 109 from a DC power supply (not shown). The resulting electrostatic force attracts and holds the edge ring F on the upper surface 104b at the periphery of the electrostatic chuck 104. The electrode 109 is a bipolar type including a pair of electrodes 109a, 109b, as shown in FIG. 3. In this embodiment, the central portion of the electrostatic chuck 104 where the electrode 108 is provided and the peripheral portion where the electrode 109 is provided are integrated, but the central portion and the peripheral portion may be separate. In addition, in this embodiment, the electrode 109 for attracting and holding the edge ring F is a bipolar type, but it may be a unipolar type.

[0043] In addition, the central portion of the electrostatic chuck 104 is formed, for example, with a diameter smaller than the diameter of the wafer W, so that when the wafer W is placed on the upper surface 104a, as shown in FIG. 2, the peripheral portion of the wafer W protrudes from the central portion of the electrostatic chuck 104. The edge ring F has a step formed on its upper portion, and the upper surface of the outer periphery is higher than the upper surface of the inner periphery. The inner periphery of the edge ring F is formed to be recessed under the peripheral edge of the wafer W that protrudes from the center of the electrostatic chuck 104. In other words, the inner diameter of the edge ring F is smaller than the outer diameter of the wafer W.

[0044] The insulator 105 is a cylindrical member made of ceramic or the like, and supports the electrostatic chuck 104. The insulator 105 is formed, for example, to have an outer diameter equal to the outer diameter of the lower electrode 103, and supports the peripheral portion of the lower electrode 103. The insulator 105 is provided such that its inner circumferential surface is positioned radially outward of the electrostatic chuck 104 relative to a lifting mechanism 114 described below.

[0045] The lift pins 106 are columnar members that rise and fall so as to protrude and sink from the top surface 104a at the center of the electrostatic chuck 104, and are formed of, for example, ceramic. Three or more lift pins 106 are provided at intervals from each other along the circumferential direction of the electrostatic chuck 104, i.e., along the circumferential direction of the top surface 104a. The lift pins 106 are provided, for example, at equal intervals along the circumferential direction. The lift pins 106 are provided to extend in the vertical direction.

[0046] The lift pins 106 are connected to a lift mechanism 110 that raises and lowers the lift pins 106. The lift mechanism 110 has, for example, a support member 111 that supports the multiple lift pins 106, and a drive unit 112 that generates a driving force for raising and lowering the support member 111 and raises and lowers the multiple lift pins 106. The drive unit 112 has a motor (not shown) that generates the driving force.

[0047] The lift pin 106 is inserted into a through hole 113 that extends downward from an upper surface 104a of the central portion of the electrostatic chuck 104 to the bottom surface of the lower electrode 103. In other words, the through hole 113 is formed so as to penetrate through the central portion of the electrostatic chuck 104 and the lower electrode 103.

[0048] The lift pins 107 are columnar members that rise and fall so as to protrude and sink from the upper surface 104b of the peripheral portion of the electrostatic chuck 104, and are made of, for example, alumina, quartz, SUS, or the like. Three or more lift pins 107 are provided at intervals from each other along the circumferential direction of the electrostatic chuck 104, i.e., along the circumferential direction of the upper surface 104a of the central portion and the upper surface 104b of the peripheral portion. The lift pins 107 are provided, for example, at equal intervals along the circumferential direction. The lift pins 107 are provided to extend in the vertical direction. The thickness of the lift pin 107 is, for example, 1 to 3 mm.

[0049] The lift pins 107 are connected to a lift mechanism 114 that drives the lift pins 107. The lift mechanism 114 has, for example, a support member 115 that is provided for each lift pin 107 and supports the lift pins 107 so that they can move horizontally. The support member 115 has, for example, a thrust bearing to support the lift pins 107 so that they can move horizontally. The lift mechanism 114 also has a drive unit 116 that generates a drive force to lift and lower the support member 111 and raise and lower the lift pins 107. The drive unit 116 has a motor (not shown) that generates the drive force.

[0050] The lift pins 107 are inserted into through holes 117 that extend downward from an upper surface 104b of the peripheral portion of the electrostatic chuck 104 to the bottom surface of the lower electrode 103. In other words, the through holes 117 are formed so as to penetrate the peripheral portion of the electrostatic chuck 104 and the lower electrode 103. The through-hole 117 is formed with a positional accuracy higher than at least the transportation accuracy of the edge ring by the transportation device 70 .

[0051] Each of the lift pins 107 is formed, for example, in a cylindrical shape except for its upper end, which is formed in a semispherical shape that gradually tapers toward the top. When the upper ends of the lift pins 107 are raised, they come into contact with the bottom surface of the edge ring F to support the edge ring F. As shown in FIG. 3, recesses F1 formed from a concave surface F1a recessed upward are provided at positions on the bottom surface of the edge ring F corresponding to each of the lift pins 107.

[0052] In a plan view, the size D1 of the recess F1 (the opening diameter) of the edge ring F is greater than the transport accuracy (error) (±X μm) of the edge ring F by the transport device 70 above the upper surface 104b of the electrostatic chuck 104, and is greater than the size D2 of the upper ends of the lift pins 107. For example, the relationships D1>D2 and D1>2X are satisfied, and D1 is approximately 0.5 mm. As another example, D1 may be 0.5 to 3 mm.

[0053] Furthermore, as described above, the upper end of the lift pin 107 is formed in a semi-spherical shape that gradually tapers toward the top, and the concave surface F1a that forms the recess F1 of the edge ring F is set to have a smaller curvature than the convex surface (i.e., the upper end surface) 107a that forms the semi-spherical shape of the upper end of the lift pin 107. In other words, the concave surface F1a has a larger radius of curvature than the convex surface 107a.

[0054] When the thickness of the outer periphery of the edge ring F is 3 to 5 mm, the depth of the recess F1 is set to, for example, 0.5 to 1 mm. The edge ring F is made of a material such as Si or SiC.

[0055] As shown in FIG. 4, a heat transfer gas supply passage 118 is formed on the upper surface 104b of the peripheral portion of the electrostatic chuck 104. The heat transfer gas supply passage 118 supplies a heat transfer gas, such as helium gas, to the back surface of the edge ring F placed on the upper surface 104b. The heat transfer gas supply passage 118 is provided so as to be fluidly connected to the upper surface 104b. The opposite side of the heat transfer gas supply passage 118 from the upper surface 104b is fluidly connected to a gas supply unit 120. The gas supply unit 120 may include one or more gas sources 121 and one or more flow rate controllers 122. In one embodiment, the gas supply unit 120 is configured to supply gas from the gas source 121 to the heat transfer gas supply passage via the flow rate controller 122, for example. Each flow rate controller 122 may include, for example, a mass flow controller or a pressure-controlled flow rate controller. Although not shown in the figure, a heat transfer gas supply path similar to the heat transfer gas supply path 118 is also formed on the central upper surface 104a of the electrostatic chuck 104 in order to supply a heat transfer gas to the back surface of the wafer W placed on the upper surface 104a. Furthermore, an intake passage may be formed to vacuum-suck the edge ring F placed on the upper surface 104b of the peripheral portion of the electrostatic chuck 104. The intake passage is provided in the electrostatic chuck 104, for example, so as to be in fluid communication with the upper surface 104b. The above-mentioned heat transfer gas supply passage and the intake passage may be entirely or partially common to each other.

[0056] Returning to the description of FIG. 2, the upper electrode showerhead 102 is configured to supply one or more process gases from the gas supply 130 to the plasma processing space 100s. In one embodiment, the upper electrode showerhead 102 has a gas inlet 102a, a gas diffusion chamber 102b, and a number of gas outlets 102c. The gas inlet 102a is, for example, in fluid communication with the gas supply 130 and the gas diffusion chamber 102b. The number of gas outlets 102c are in fluid communication with the gas diffusion chamber 102b and the plasma processing space 100s. In one embodiment, the upper electrode showerhead 102 is configured to supply one or more process gases from the gas inlet 102a through the gas diffusion chamber 102b and the number of gas outlets 102c to the plasma processing space 100s.

[0057] The gas supply 130 may include one or more gas sources 131 and one or more flow controllers 132. In one embodiment, the gas supply 130 is configured to supply, for example, one or more process gases from respective gas sources 131 to the gas inlet 102a via respective flow controllers 132. Each flow controller 132 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply 130 may include one or more flow modulation devices to modulate or pulse the flow rate of one or more process gases.

[0058] The RF power supply 140 is configured to supply RF power, e.g., one or more RF signals, to one or more electrodes, such as the lower electrode 103, the upper electrode showerhead 102, or both the lower electrode 103 and the upper electrode showerhead 102. Thereby, a plasma is generated from one or more process gases supplied to the plasma processing space 100s. Thus, the RF power supply 140 may function as at least a part of a plasma generating unit configured to generate a plasma from one or more process gases in the plasma processing chamber. The RF power supply 140 includes, for example, two RF generating units 141a, 141b and two matching circuits 142a, 142b. In one embodiment, the RF power supply 140 is configured to supply a first RF signal from the first RF generating unit 141a through the first matching circuit 142a to the lower electrode 103. For example, the first RF signal may have a frequency in the range of 27 MHz to 100 MHz.

[0059] In one embodiment, the RF power supply unit 140 is configured to supply a second RF signal from the second RF generating unit 141b to the lower electrode 103 via the second matching circuit 142b. For example, the second RF signal may have a frequency in the range of 400 kHz to 13.56 MHz. Alternatively, a DC (Direct Current) pulse generating unit may be used in place of the second RF generating unit 141b.

[0060] Further, although not shown, other embodiments are contemplated in the present disclosure. For example, in an alternative embodiment, the RF power supply 140 may be configured to provide a first RF signal from an RF generator to the lower electrode 103, a second RF signal from another RF generator to the lower electrode 103, and a third RF signal from yet another RF generator to the lower electrode 103. Additionally, in another alternative embodiment, a DC voltage may be applied to the upper electrode showerhead 102.

[0061] Still further, in various embodiments, one or more RF signals (i.e., the first RF signal, the second RF signal, etc.) may be pulsed or modulated in amplitude. Amplitude modulation may include pulsing the RF signal amplitude between an on state and an off state, or between two or more different on states.

[0062] The exhaust system 150 may be connected to, for example, an exhaust port 100e provided at the bottom of the plasma processing chamber 100. The exhaust system 150 may include a pressure valve and a vacuum pump. The vacuum pump may include a turbomolecular pump, a roughing pump, or a combination thereof.

[0063] Next, a description will be given of an example of wafer processing performed using the processing module 60 configured as above. In the processing module 60, processing such as etching, film formation, and diffusion is performed on the wafer W.

[0064] First, a wafer W is carried into the plasma processing chamber 100, and the wafer W is placed on the electrostatic chuck 104 by raising and lowering the lift pins 106. Then, a DC voltage is applied to the electrode 108 of the electrostatic chuck 104, so that the wafer W is electrostatically attracted to and held on the electrostatic chuck 104 by electrostatic force. After the wafer W is carried in, the inside of the plasma processing chamber 100 is depressurized to a predetermined vacuum level by the exhaust system 150.

[0065] Next, a processing gas is supplied from the gas supply unit 130 to the plasma processing space 100s via the upper electrode showerhead 102. In addition, high frequency power HF for plasma generation is supplied from the RF power supply unit 140 to the lower electrode 103, thereby exciting the processing gas to generate plasma. At this time, high frequency power LF for ion attraction may be supplied from the RF power supply unit 140. Then, the wafer W is subjected to plasma processing by the action of the generated plasma.

[0066] During plasma processing, a heat transfer gas such as He gas or Ar gas is supplied to the bottom surfaces of the wafer W and edge ring F attracted and held on the electrostatic chuck 104 via the heat transfer gas supply path 118 or the like.

[0067] When the plasma processing is terminated, the supply of the heat transfer gas to the bottom surface of the wafer W may be stopped. In addition, the supply of the high frequency power HF from the RF power supply unit 140 and the supply of the processing gas from the gas supply unit 130 are stopped. If the high frequency power LF has been supplied during the plasma processing, the supply of the high frequency power LF is also stopped. Next, the adsorption and holding of the wafer W by the electrostatic chuck 104 is stopped.

[0068] Thereafter, the wafer W is raised by the lift pins 106, and the wafer W is detached from the electrostatic chuck 104. When the wafer W is detached, a charge removal process may be performed on the wafer W. Then, the wafer W is unloaded from the plasma processing chamber 100, and a series of wafer processing steps is completed.

[0069] During the wafer processing, the edge ring F is attracted and held by electrostatic force. Specifically, during the plasma processing, and before and after the plasma processing, different voltages are applied to the electrodes 109a and 109b so that a potential difference occurs between the electrodes 109a and 109b. The edge ring F is attracted and held by electrostatic force corresponding to the potential difference generated by the above. In contrast, during the plasma processing, the same voltage (e.g., the same positive voltage) is applied to the electrodes 109a and 109b, and a potential difference occurs between the edge ring F, which is set to the ground potential through the plasma, and the electrodes 109a and 109b. The edge ring F is attracted and held by electrostatic force corresponding to the potential difference generated by the above. During the time when the edge ring F is attracted by electrostatic force, the lift pins 107 are recessed from the upper surface 104b of the peripheral portion of the electrostatic chuck 104.

[0070] As described above, the edge ring F is attracted and held by electrostatic force, so that no positional deviation occurs between the edge ring F and the electrostatic chuck 104 when the supply of heat transfer gas to the bottom surface of the edge ring F begins.

[0071] Next, an example of a process for mounting the edge ring F in the processing module 60 using the above-mentioned plasma processing system 1 will be described with reference to Figs. 5 to 7. Figs. 5 to 7 are diagrams that typically show the state inside the processing module 60 during the mounting process. The following process is performed under the control of the control device 80. The following process is performed, for example, when the electrostatic chuck 104 is at room temperature.

[0072] First, the transfer arm 71 holding the edge ring F is inserted through a transfer port (not shown) into the reduced-pressure plasma processing chamber 100 of the processing module 60 to which the edge ring F is to be attached from the transfer module 50 in the vacuum atmosphere of the plasma processing system 1. Then, as shown in Fig. 5, the edge ring F held by the transfer arm 71 is transferred above the upper surface 104b of the peripheral portion of the electrostatic chuck 104. The edge ring F is held by the transfer arm 71 with its circumferential orientation adjusted.

[0073] Next, all the lift pins 107 are raised, and the edge ring F is transferred from the transport arm 71 to the lift pins 107 as shown in FIG. 6. Specifically, all the lift pins 107 are raised, and first, the upper ends of the lift pins 107 come into contact with the bottom surface of the edge ring F held by the transport arm 71. At this time, the upper ends of the lift pins 107 are accommodated in the recesses F1 provided in the bottom surface of the edge ring F. This is because, as described above, the recesses F1 are provided at positions corresponding to the lift pins 107 on the bottom surface of the edge ring F, and the size of the recesses F1 is larger than the transport accuracy of the edge ring F by the transport device 70 and larger than the size of the upper ends of the lift pins 107 in a plan view. If the lift pins 107 continue to rise after the upper ends of the lift pins 107 come into contact with the bottom surface of the edge ring F, the edge ring F is transferred to and supported by the lift pins 107 as shown in FIG. 6.

[0074] As described above, the concave surface F1a forming the concave portion F1 of the edge ring F is set to have a smaller curvature than the convex surface 107a forming the hemispherical shape of the upper end of the lift pin 107. Therefore, even if the edge ring F is misaligned with respect to the lift pin 107 immediately after being transferred to the lift pin 107, the edge ring F moves as follows and is positioned with respect to the lift pin 107. That is, the edge ring F moves such that the tops of the upper ends of the lift pins 107 relatively slide on the concave surface F1a of the edge ring F. The edge ring F stops at a position where the center of the concave portion F1 and the center of the upper ends of the lift pins 107 coincide with each other in a plan view, that is, where the deepest part of the concave portion F1 and the tops of the upper ends of the lift pins 107 coincide with each other in a plan view, and is positioned with respect to the lift pins 107 at that position.

[0075] After the edge ring F is handed over to the lift pins 107, in order to facilitate the movement for positioning as described above, each of the lift pins 107 may be moved up and down in small increments, or each of the lift pins 107 may be lowered at a different speed or at a high speed.

[0076] After the edge ring F is positioned relative to the lift pins 107, the transport arm 71 is removed from the plasma processing chamber 100 and the lift pins 107 are lowered, so that the edge ring F is placed on the upper surface 104a of the peripheral portion of the electrostatic chuck 104, as shown in FIG. 7. Since the edge ring F is positioned relative to the lift pins 107 as described above, and the through hole 117 and the lift pins 107 are provided with high precision relative to the center of the electrostatic chuck 104, the edge ring F is placed on the upper surface 104a while being positioned relative to the center of the electrostatic chuck 104. The lift pins 107 are lowered, for example, until the upper end surfaces of the lift pins 107 are recessed below the upper surface 104 a of the peripheral portion of the electrostatic chuck 104 .

[0077] Thereafter, a DC voltage is applied from a DC power supply (not shown) to electrode 109 provided on the peripheral portion of electrostatic chuck 104, and the edge ring F is attracted and held on upper surface 104b by the electrostatic force generated thereby. Specifically, different voltages are applied to electrodes 109a and 109b, and the edge ring F is attracted and held on upper surface 104b by the electrostatic force generated according to the potential difference. This completes the process of attaching the edge ring F.

[0078] In addition, when the above-mentioned intake path is provided, after the edge ring F is placed on the upper surface 104b, it may be possible to vacuum-adsorb it to the upper surface 104b using the intake path before it is adsorbed and held by electrostatic force. Then, after switching from vacuum adsorption using the intake path to adsorption and holding by electrostatic force, the degree of vacuum in the intake path may be measured, and based on the measurement result, it may be determined whether to place the edge ring F back on the upper surface 104b.

[0079] The process of removing the edge ring F is performed in the reverse order to the process of attaching the edge ring F described above. When removing the edge ring F, a cleaning process may be performed on the edge ring F before the edge ring F is carried out from the plasma processing chamber 100.

[0080] As described above, the wafer support table 101 according to the present embodiment includes the upper surface 104a on which the wafer W is placed, the upper surface 104b on which the edge ring F is placed so as to surround the wafer W held on the upper surface, three or more lift pins 107 that rise and fall so as to protrude and sink from the upper surface 104b, and a lift mechanism 114 that raises and lowers the lift pins 107. In addition, recesses F1 formed of a concave surface F1a recessed upward are provided at positions on the bottom surface of the edge ring F corresponding to the respective lift pins 107. In addition, the size of the recesses F1 is formed to be larger than the conveyance error of the edge ring F above the upper surface 104b and larger than the size of the upper end of the lift pin 107 in a plan view. Therefore, when the lift pins 107 are raised to abut against the bottom surface of the edge ring F, the upper end of the lift pin 107 can be accommodated in the recesses F1 of the edge ring F. Furthermore, in this embodiment, the upper end of the lift pin 107 is formed in a semi-spherical shape that gradually narrows toward the top, and the concave surface F1a forming the recess F1 has a smaller curvature than the convex surface forming the semi-spherical shape of the upper end of the lift pin 107. Therefore, when the edge ring F is supported by the lift pin 107, the edge ring F can be positioned relative to the lift pin 107 at a position where the deepest part of the recess F1 and the top of the upper end of the lift pin 107 coincide with each other in a plan view. Therefore, when the lift pin 107 supporting the edge ring F is lowered, the lift pin 107 can be positioned relative to the electrostatic chuck 104 and placed on the upper surface 104b. In other words, according to this embodiment, the edge ring F can be positioned and placed relative to the wafer support table 101 regardless of the conveyance accuracy of the edge ring F. Moreover, if the wafer support table 101 according to the present embodiment is provided in the plasma processing apparatus, the edge ring F can be replaced using the transport device 70 without the intervention of an operator. When an operator replaces the edge ring, the processing vessel in which the edge ring is disposed needs to be opened to the atmosphere. However, if the wafer support table 101 according to the present embodiment is provided, the edge ring F can be replaced using the transport device 70, so that the plasma processing chamber 100 does not need to be opened to the atmosphere during replacement. Therefore, according to the present embodiment, the time required for replacement can be significantly reduced. Furthermore, in the present embodiment, three or more lift pins are provided, so that the edge ring F can be aligned in the circumferential direction in addition to the radial direction (the direction from the center of the wafer support table 101 toward the outer periphery).

[0081] Furthermore, in this embodiment, a lifting mechanism 114 is provided for each lifting pin 107, and further includes a support member 115 that supports the lifting pins 107 so that the lifting pins 107 are movable in the horizontal direction. Therefore, when the electrostatic chuck 104 thermally expands or contracts, the lifting pins 107 can move in the horizontal direction in accordance with the thermal expansion or contraction. Therefore, the lifting pins 107 will not be damaged when the electrostatic chuck 104 thermally expands or contracts.

[0082] Furthermore, in this embodiment, after the edge ring F is placed, it is attracted and held by electrostatic force using the electrode 109. Therefore, it is not necessary to provide a protrusion, a recess, or the like for suppressing misalignment of the edge ring F after placement on the bottom surface of the edge ring F or on the placement surface of the edge ring F (upper surface 104b of the electrostatic chuck 104). In particular, since it is not necessary to provide the above-mentioned protrusions or the like on the upper surface 104b of the electrostatic chuck 104, it is possible to prevent the configuration of the electrostatic chuck 104 from becoming complicated.

[0083] Furthermore, in this embodiment, since there is no other member between the electrostatic chuck 104 of the wafer support table 101 and the edge ring F, the cumulative tolerance is small.

[0084] FIG. 8 is a diagram for explaining another example of the lift pin. The lift pin 160 in FIG. 8 has a columnar portion 162 and a connecting portion 163 in addition to an upper end portion 161 formed in a hemispherical shape.

[0085] The columnar portion 162 is formed in a columnar shape that is thicker than the upper end portion 161, and specifically, for example, is formed in a cylindrical shape that is thicker than the upper end portion 161. The connecting portion 163 is a portion that connects the upper end portion 161 and the columnar portion 162. This connecting portion is formed in a frustum shape that gradually becomes thinner toward the top, and specifically, for example, the lower end thereof is formed in a frustum shape having the same diameter as the columnar portion 162 and the upper end thereof is formed in the same diameter as the upper end portion 161.

[0086] By using the lift pins 160, the positioning accuracy of the edge ring F with respect to the lift pins 160 can be improved. In addition, by using the lift pins 107 described above, the recess F1 can be made shallower, so that the edge ring F can be made thinner and lighter.

[0087] FIG. 9 is a diagram for explaining another example of the electrostatic chuck. In the electrostatic chuck 170 of FIG. 9, an insulating guide 180 is provided in the through hole 117 through which the lift pin 107 is inserted. The guide 180 is, for example, a cylindrical member made of resin, and is fitted into the through hole 117 . In the electrostatic chuck 170, the lift pins 107 are inserted into guides 180 provided in the through holes 117, and the movement direction of the lift pins 107 when they are raised and lowered is determined in the up-down direction by the guides 180. Therefore, the upper ends of the lift pins 107 are positioned with higher precision relative to the electrostatic chuck 170. Therefore, when the lift pins 107, which position and support the edge ring F, are lowered to place the edge ring F on the upper surface 104b of the electrostatic chuck 170, the edge ring F can be placed on the upper surface 104b in a state where it is positioned with higher precision relative to the electrostatic chuck 170.

[0088] Second embodiment FIG. 10 is a partially enlarged cross-sectional view showing the outline of the configuration of a wafer support table 200 serving as a substrate support table according to the second embodiment. In the first embodiment, the edge ring F is the object to be replaced, but in this embodiment, the cover ring C is the object to be replaced. The cover ring C is an annular member that covers the outer surface of the edge ring F in the circumferential direction.

[0089] The wafer support table 200 in FIG. 10 includes a lower electrode 201, an electrostatic chuck 202, a support 203, an insulator 204, and lifting pins 205 serving as a lifter. 2 and the like are provided with through-holes 117 passing therethrough, but the lower electrode 201 and the electrostatic chuck 202 are not provided with through-holes 117. In this respect, the lower electrode 201 and the electrostatic chuck 202 are different from the lower electrode 103 and the electrostatic chuck 104.

[0090] The support 203 is a member formed in a ring shape in a planar view using, for example, quartz, and supports the lower electrode 103 as well as the covering C. An upper surface 203a of the support 203 serves as an annular member mounting surface on which the covering C as the annular member to be replaced is placed.

[0091] The insulator 204 is a cylindrical member made of ceramic or the like, and supports the support 203. The insulator 204 is formed, for example, to have an outer diameter equal to the outer diameter of the support 203, and supports the periphery of the support 203.

[0092] 2 etc. are inserted into through holes 117 provided so as to penetrate the lower electrode 103 and the electrostatic chuck 104, whereas the lift pins 205 are inserted into through holes 206 that penetrate the support 203 in the up-down direction from the upper surface 203a. In this respect, the lift pins 205 differ from the lift pins 107. Similar to the lift pins 107, three or more lift pins 205 are provided at intervals from each other along the circumferential direction of the electrostatic chuck 202.

[0093] Like the lift pins 107, the lift pins 205 have upper ends formed in a semispherical shape that gradually tapers upward. When the upper ends of the lift pins 205 are raised, they come into contact with the bottom surface of the covering C to support the covering C. At positions on the bottom surface of the covering C corresponding to the lift pins 205, recesses C1 formed from concave surfaces C1a recessed upward are provided.

[0094] In plan view, the size of the recess C1 of the covering C is greater than the transportation accuracy of the covering C by the transportation device 70 and is also greater than the size of the upper ends of the lift pins 205. Furthermore, as described above, the upper end of the lifting pin 205 is formed into a hemispherical shape that gradually becomes thinner toward the top, and the concave surface C1a that forms the recess C1 of the cover ring C is set to have a smaller curvature than the convex surface 205a that forms the above-mentioned hemispherical shape of the upper end of the lifting pin 205.

[0095] The process of attaching and removing the cover ring C is similar to the process of attaching and removing the edge ring F according to the first embodiment, and therefore a description thereof will be omitted. 2 and the like, the lift pins 107 for the edge ring F are configured to be capable of protruding and retracting from the upper surface 104b of the peripheral portion of the electrostatic chuck 104. When the edge ring F is attracted by electrostatic force, the upper end surfaces of the lift pins 107 are recessed from the upper surface 104a of the peripheral portion of the electrostatic chuck 104. In contrast, the lift pins 205 for the cover ring C do not have to be configured to be capable of protruding and retracting from the upper surface 203a of the support 203 as long as they are configured to be capable of protruding from the upper surface 203a of the support 203 and the amount of protrusion is adjustable. Also, when the edge ring F is attracted by electrostatic force, the upper end surfaces of the lift pins 205 may protrude from the upper surface 203a of the support 203.

[0096] Third embodiment FIG. 11 is a partially enlarged cross-sectional view showing the outline of the configuration of a wafer support stage 300 serving as a substrate support stage according to the third embodiment. In the first embodiment, the edge ring F is the object to be replaced, and in the second embodiment, the covering ring C is the object to be replaced, but in the present embodiment, both the edge ring F and the covering ring C are the object to be replaced.

[0097] In this embodiment, the edge ring F and the cover ring C are replaced separately. Therefore, the edge ring F is provided with lift pins 107 and through holes 117, and the cover ring C is provided with lift pins 205 and through holes 206. In addition, the above-mentioned recesses F1 and C1 are formed in the bottom surface of the edge ring F and the bottom surface of the cover ring C, respectively.

[0098] In this embodiment, the processes for attaching and removing the edge ring F and the process for attaching and removing the cover ring C are similar to those for attaching and removing the edge ring F in the first embodiment, and therefore will not be described.

[0099] (Fourth embodiment) FIG. 12 is a partially enlarged cross-sectional view showing the outline of the configuration of a wafer support table 400 serving as a substrate support table according to the fourth embodiment. In the first embodiment, the edge ring F was the target of replacement, in the second embodiment, the covering ring C was the target of replacement, and in the third embodiment, both the edge ring F and the covering ring C were the target of replacement, but in this embodiment, the covering ring Ca supporting the edge ring Fa is the target of replacement.

[0100] A wafer support table 400 in FIG. 12 includes a lower electrode 401, an electrostatic chuck 402, a support 403, an insulator 404, and lifting pins 405 serving as a lifter.

[0101] The lower electrode 401 and the electrostatic chuck 402 are provided with through holes 406 through which the lift pins 405 are inserted. The through holes 406 are formed to extend downward from an upper surface 402a of the peripheral portion of the electrostatic chuck 402 to reach the bottom surface of the lower electrode 401.

[0102] The support 403 is a member made of, for example, quartz, and formed into a ring shape in a plan view, and supports the lower electrode 401 .

[0103] An upper surface 403a of the support 403 and an upper surface 402a of the peripheral portion of the electrostatic chuck 402 serve as an annular member mounting surface on which a cover ring Ca supporting an edge ring Fa as an annular member to be replaced is placed.

[0104] The insulator 404 is a cylindrical member made of ceramic or the like, and supports the support 403. The insulator 404 is formed, for example, to have an outer diameter equal to the outer diameter of the support 403, and supports the periphery of the support 403.

[0105] 2, the edge ring Fa has a step formed on its upper portion, the upper surface of the outer periphery being higher than the upper surface of the inner periphery, and the inner diameter of the edge ring Fa is smaller than the outer diameter of the wafer W. Furthermore, the edge ring Fa has a recess Fa1 that is recessed radially inward on the outer periphery of the bottom portion. On the other hand, the cover ring Ca has a protrusion Ca1 at its bottom that protrudes radially inward. The cover ring Ca supports the edge ring Fa by engagement between the protrusion Ca1 and the recess Fa1. In order to prevent misalignment between the cover ring Ca and the edge ring Fa, a protrusion may be provided on one of them and a recess for engaging with the protrusion may be provided on the other. Specifically, as with the cover ring Cb and the edge ring Fb described later with reference to Figures 20 and 21, a recess may be provided on either the upper surface of the inner periphery of the cover ring Ca or the lower surface of the outer periphery of the edge ring Fa, and a protrusion having a shape corresponding to the recess may be provided on the other. Also, the cover ring Ca and the edge ring Fa may be integrated by bonding or joining them with an adhesive or the like.

[0106] The lift pins 405 protrude and retract from positions corresponding to the protruding portions Ca1 of the cover ring Ca on the upper surface 402a of the peripheral portion of the electrostatic chuck 402. Through holes 406 through which the lift pins 405 are inserted are formed at positions corresponding to the protruding portions Ca1 of the cover ring Ca. Similar to the lift pins 107 in FIG. 2, three or more lift pins 405 are provided at intervals along the circumferential direction of the electrostatic chuck 402 .

[0107] Like the lift pins 107, the lift pins 405 have upper ends formed in a semispherical shape that gradually tapers upward. When the upper ends of the lift pins 405 are raised, they come into contact with the bottom surface of the protruding portion Ca1 of the covering Ca to support the covering C that supports the edge ring F. At positions on the bottom surface of the protruding portion Ca1 of the covering C that correspond to the lift pins 405, recesses Ca2 formed from a concave surface Ca2a that is recessed upward are provided.

[0108] In plan view, the size of the recess Ca2 is larger than the conveying accuracy of the covering C by the conveying device 70 and is also larger than the size of the upper end of the lift pin 405. Furthermore, as described above, the upper end of the lift pin 405 is formed into a hemispherical shape that gradually becomes thinner toward the top, and the concave surface Ca2a that forms the recess Ca2 is set to have a smaller curvature than the convex surface 405a that forms the hemispherical shape of the upper end of the lift pin 405.

[0109] The process of attaching and removing the cover ring Ca while supporting the edge ring Fa is similar to the process of attaching and removing the edge ring F according to the first embodiment, and therefore the description thereof will be omitted.

[0110] According to the present embodiment, the edge ring Fa and the cover ring Ca can be replaced simultaneously, which shortens the time required for replacing them. In addition, since there is no need to provide a mechanism for lifting and lowering the edge ring Fa and a mechanism for lifting and lowering the cover ring Ca separately, the cost can be reduced.

[0111] When the wafer support table according to this embodiment is used, it is possible to remove only the edge ring Fa. The process of removing the edge ring Fa will be described below with reference to FIGS.

[0112] First, all of the lift pins 405 are lifted, and the cover ring C supporting the edge ring F is transferred from the upper surface 402a of the peripheral portion of the electrostatic chuck 402 and the upper surface 403a (hereinafter, annular member mounting surface) of the support 403 to the lift pins 405. Thereafter, the lift pins 405 continue to lift, and the cover ring Ca supporting the edge ring Fa moves upward, as shown in FIG.

[0113] Next, the transfer arm 71 holding the jig J is inserted from the transfer module 50 in the vacuum atmosphere of the plasma processing system 1 into the reduced pressure plasma processing chamber 100 through a load / unload port (not shown). Then, as shown in Fig. 14, the jig J held by the transfer arm 71 is moved between the annular member mounting surface and upper surface 403a of the support body 403 and the cover ring Ca supporting the edge ring Fa. The jig J is a disk-shaped member having approximately the same diameter as the wafer W, i.e., a diameter larger than the inner diameter of the edge ring Fa.

[0114] Next, the lift pins 106 are raised, and the jig J is transferred from the transfer arm 71 to the lift pins 106, as shown in FIG.

[0115] Next, the transfer arm 71 is extracted, i.e., retreated, from the plasma processing chamber 100, and then the lift pins 405 and the lift pins 106 are moved relatively to each other, specifically, only the lift pins 405 are lowered. As a result, the edge ring Fa is transferred from the covering ring Ca to the jig J, as shown in Fig. 16. Thereafter, only the lift pins 405 are continued to be lowered, and as a result, the covering ring Ca is transferred from the lift pins 405 to the annular member mounting surface.

[0116] Next, the transfer arm 71 is inserted into the plasma processing chamber 100 through a load / unload port (not shown). Then, as shown in FIG. 17, the transfer arm 71 is moved between the cover ring Ca and the jig J supporting the edge ring Fa.

[0117] Next, the lift pins 106 are lowered, and the jig J supporting the edge ring Fa is transferred from the lift pins 106 to the transfer arm 71, as shown in FIG.

[0118] Then, the transfer arm 71 is extracted from the plasma processing chamber 100, and the jig J supporting the edge ring Fa is carried out from the plasma processing chamber 100. This completes the series of processes for removing only the edge ring Fa.

[0119] The process of attaching only the edge ring Fa is performed in the reverse order to the process of removing only the edge ring Fa described above.

[0120] Fifth embodiment FIG. 19 is a partially enlarged cross-sectional view showing the outline of the configuration of a wafer support table 500 serving as a substrate support table according to the fifth embodiment. In this embodiment, both an edge ring and a cover ring are used, as in the third and fourth embodiments. Also, in this embodiment, as in the fourth embodiment, the edge ring and the cover ring can be replaced simultaneously, and only the edge ring or only the cover ring can be replaced. However, in this embodiment, when replacing only the edge ring, a jig such as that used in the fourth embodiment is not required.

[0121] A wafer support table 500 in FIG. 19 includes a lower electrode 501, an electrostatic chuck 502, a support 503, and lifting pins 504 as an example of a lifter.

[0122] 12, the support 503 is a member formed in a ring shape in a planar view using, for example, quartz, etc., and supports the lower electrode 501. However, in the example of Fig. 12, the support 403 is provided so as not to overlap the lower electrode 401 in a planar view, whereas in the example of Fig. 19, the support 503 is provided so that its upper portion protrudes toward the inner periphery and overlaps the lower electrode 501.

[0123] 12, the through holes 406 through which the lift pins 405 are inserted are provided so as to penetrate the lower electrode 401 and the electrostatic chuck 402. In contrast, in the example of FIG. 19, the through holes 505 through which the lift pins 504 are inserted are provided so as to penetrate the lower electrode 501 but not the electrostatic chuck 502, and instead penetrate the inner periphery of the upper part of the support 503. The through holes 505 are formed so as to extend downward from the upper surface 502a of the peripheral part of the electrostatic chuck 502 to the bottom surface of the lower electrode 501. The through holes 505 may be provided so as to penetrate the lower electrode 501 and the electrostatic chuck 502, as in the example of FIG. 12.

[0124] 2, the electrostatic chuck 502 may be provided with an electrode 109 for attracting and holding the edge ring Fb by electrostatic force. Specifically, the electrode 109 is provided in a portion that overlaps with the edge ring Fb in a plan view but does not overlap with the cover ring Cb in a plan view, similar to the electrostatic chuck 402 in FIG. 12. The electrode 109 may be provided in the electrostatic chuck 502, or may be provided in a dielectric body separate from the electrostatic chuck 502.

[0125] An upper surface 502a of the peripheral portion of the electrostatic chuck 502 and an upper surface 503a of the support 503 serve as annular member mounting surfaces on which the edge ring Fb and the cover ring Cb are mounted.

[0126] In this embodiment, similarly to the fourth embodiment, the cover ring Cb is configured to be able to support the edge ring Fb, and is formed so as to at least partially overlap the edge ring Fb in a plan view when it is concentric with the edge ring Fb. In one embodiment, the diameter of the innermost periphery of the cover ring Cb is smaller than the diameter of the outermost periphery of the edge ring Fb, and when the cover ring Cb and the edge ring Fb are arranged so as to overlap over the entire circumference, the inner periphery of the cover ring Cb at least partially overlaps the outer periphery of the edge ring Fb in a plan view. For example, in one embodiment, the edge ring Fb has a recess Fb1 recessed radially inward on the outer periphery of the bottom, and the cover ring Cb has a protrusion Cb1 protruding radially inward on its bottom, and the edge ring Fb is supported by engagement between the protrusion Cb1 and the recess Fb1.

[0127] The bottom surface of the outer periphery of the edge ring Fb is provided with recesses Fb2 formed from recessed surfaces Fb2a recessed upward at positions corresponding to the lift pins 504. The recesses Fb2 are provided in portions overlapping with the inner periphery of the cover ring Cb (specifically, for example, the protrusions Cb1) in a plan view.

[0128] The cover ring Cb has through holes Cb2 leading to the recesses Fb2 of the edge ring Fb, through which the lift pins 504 are inserted, at positions corresponding to the lift pins 504. The through holes Cb2 are provided in an inner periphery (specifically, for example, the protrusions Cb1) of the cover ring Cb that overlaps with the outer periphery of the edge ring Fb in a plan view.

[0129] In this embodiment, the edge ring Fb, like the edge ring F in Figure 2, has a step formed on the upper part of its inner circumference, the upper surface of the outer circumference is formed higher than the upper surface of the inner circumference, and the inner diameter is smaller than the outer diameter of the wafer W.

[0130] In order to prevent misalignment between the cover ring Cb and the edge ring Fb, a protrusion may be provided on one of them, and a recess to be engaged with the protrusion may be provided on the other of them. Specifically, as shown in FIG. 20, a protrusion (hereinafter referred to as an "annular protrusion") Cb3 may be formed on the upper surface of the inner peripheral part of the cover ring Cb over the entire circumference along the curvature of the cover ring Cb, and a recess (hereinafter referred to as an "annular recess") Fb3 may be formed on the lower surface of the outer peripheral part of the edge ring Fb over the entire circumference along the curvature of the edge ring F at a position corresponding to the annular protrusion Cb3. The engagement between the annular protrusion Cb3 and the annular recess Fb3 can suppress misalignment between the cover ring Cb and the edge ring Fb. Furthermore, by providing the annular protrusion Cb3 and the annular recess Fb3 in this manner, a path from a gap G between the outer peripheral end of the edge ring Fb and the cover ring Cb, which opens into the plasma processing space 100s, through a gap between the outer peripheral part of the edge ring F and the inner peripheral part of the cover ring Cb, to the electrostatic chuck 502 has a labyrinth structure. Therefore, it is possible to prevent the activated species in the plasma from reaching the electrostatic chuck 502 via the above-mentioned route.

[0131] In the example of FIG. 20, the annular protrusion Cb3 and the annular recess Fb3 are provided on the inner peripheral side of the recess Fb2, but they may be provided on the outer peripheral side of the recess Fb2. Furthermore, as shown in FIG. 21, the annular protrusion Cb3 and the annular recess Fb3 may be provided at a position overlapping with the recess Fb2 in a plan view.

[0132] Instead of the above example, a recess may be formed on the upper surface of the inner periphery of the cover ring Cb, and a protrusion having a shape corresponding to the recess of the cover ring Cb may be formed on the lower surface of the outer periphery of the edge ring Fb. This also makes it possible to suppress misalignment between the cover ring Cb and the edge ring Fb, and to form the labyrinth structure.

[0133] The lift pins 504 are configured to be capable of protruding from an upper surface 503a of the inner periphery of the support 503, and are raised and lowered so that the amount of protrusion from the upper surface 503a can be adjusted. Specifically, the lift pins 504 are configured to be capable of protruding from positions on the upper surface 503a of the inner periphery of the support 503 that overlap with the edge ring Fb and the cover ring Cb in a plan view. Through holes 505 through which the lift pins 504 are inserted are formed in positions that overlap with the edge ring Fb and the cover ring Cb in a plan view. Similar to the lift pins 107 in FIG. 2, three or more lift pins 504 are provided at intervals along the circumferential direction of the electrostatic chuck 502 .

[0134] Like the lift pins 107, the lift pins 504 have upper ends formed in a semispherical shape that gradually tapers upward. The upper ends of the lift pins 504 form an edge ring support portion that engages with the recessed portion Fb2 of the edge ring Fb and supports the edge ring Fb. When the lift pins 504 are raised, their upper ends pass through the through holes Cb2 of the cover ring Cb and come into contact with the recessed portion Fb2 in the bottom surface of the edge ring Fb, thereby supporting the edge ring Fb from the bottom surface.

[0135] In plan view, the size of the recess Fb2 is greater than the transportation accuracy of the edge ring Fb by the transportation device 70 and is greater than the size of the upper end of the lift pins 504. Furthermore, as described above, the upper ends of the lift pins 504 are formed in a semispherical shape that gradually tapers toward the top, and the concave surface Fb2a that forms the recess Fb2 is set to have a smaller curvature than the convex surface 504a that forms the semispherical shape of the upper ends of the lift pins 504. This makes it possible to position the edge ring Fb with respect to the lift pins 504. The positioning accuracy of the edge ring Fb by the upper ends of the lift pins 504, i.e., the edge ring support portions, is, for example, less than 100 μm.

[0136] Further, the lift pin 504 has a covering ring support portion 504b that supports the covering ring Cb below the upper end portion that constitutes the edge ring support portion. The covering ring support portion 504b is configured to abut on the bottom surface of the covering ring Cb without passing through the through hole Cb2 of the covering ring Cb, thereby supporting the covering ring Cb from the bottom surface.

[0137] Also, the covering ring support portion 504b may be formed so that the covering ring Cb is positioned with respect to the lifting pins 504. Specifically, for example, as shown in FIG. 19, a chamfering process may be performed around the lower part of the through hole Cb of the covering ring Cb to form a chamfered portion, and the upper end portion of the covering ring support portion 504b may be formed in a tapered shape corresponding to the chamfered portion. In other words, the lower opening of the through hole Cb2 of the covering ring Cb may be formed so as to be gradually wider downward, and the upper end portion of the covering ring support portion 504b may be formed in a shape corresponding to the lower opening of the through hole Cb2 of the covering ring Cb, and may be formed so as to be gradually thinner upward. This allows the covering ring Cb to be positioned with respect to the lifting pins 504 at a position where the center of the through hole Cb2 and the center of the covering ring support portion 504b coincide in a plan view.

[0138] Furthermore, in plan view, the size of the lower opening of the through hole Cb2 of the covering Cb may be larger than the transport accuracy of the covering Cb supporting the edge ring Fb by the transport device 70, and may be larger than the size of the upper end of the covering support portion 504b of the lift pins 504. This allows the upper end of the covering support portion 504b to be reliably accommodated in the lower opening of the through hole Cb2 of the covering Cb when the lift pins 504 are lifted to bring the covering support portion 504b into contact with the bottom surface of the covering Cb.

[0139] In addition, when the covering ring support portion 504b is formed so that the covering ring Cb is positioned relative to the lifting pins 504, the positioning accuracy of the edge ring Fb by the upper end portion of the lifting pins 504, i.e., the edge ring support portion, is higher than the positioning accuracy of the covering ring Cb by the covering ring support portion 504b.

[0140] Next, an example of a process for simultaneously attaching the edge ring Fb and the cover ring Cb will be described with reference to Fig. 22 to Fig. 24. Fig. 22 to Fig. 24 are diagrams showing the state around the wafer support table 500 during the above process. The following process is performed under the control of the control device 80.

[0141] First, the transfer arm 71 holding the cover ring Cb supporting the edge ring Fb is inserted through an entrance (not shown) into the depressurized plasma processing chamber 100 of the processing module 60 to be attached. Then, as shown in Fig. 22, the cover ring Cb supporting the edge ring Fb is transferred by the transfer arm 71 above the upper surface 502a of the peripheral portion of the electrostatic chuck 502 and the upper surface 503a of the support 503 (hereinafter, sometimes abbreviated as "annular member mounting surface of the wafer support table 500").

[0142] 23, the edge ring Fb is transferred from the cover ring Cb held by the transport arm 71 to the upper ends of the lift pins 504 that have passed through the through holes Cb2 of the cover ring Cb. At this time, the upper ends of the lift pins 504 fit into the recesses Fb2 provided in the bottom surface of the outer periphery of the edge ring Fb, and the edge ring Fb is positioned with respect to the lift pins 504 by the recesses Fb2a (see FIG. 19) that form the recesses Fb2 and the convex surfaces 504a of the lift pins 504.

[0143] 24, the covering Cb is transferred from the transport arm 71 to the covering support parts 504b of the lifting pins 504. At this time, the covering Cb is positioned relative to the lifting pins 504 by, for example, the covering support parts 504b of the lifting pins 504 and the shape of the lower opening of the through-hole Cb2 of the covering Cb.

[0144] Then, the transfer arm 71 is removed from the plasma processing chamber 100 and the lift pins 504 are lowered, whereby the edge ring Fb and the cover ring Cb are placed on the annular member mounting surface of the wafer support table 500. Thereafter, a DC voltage is applied from a DC power supply (not shown) to the electrode 109 provided on the electrostatic chuck 502, and the edge ring Fb is attracted and held by the electrostatic force generated thereby. This completes a series of steps for simultaneously attaching the edge ring Fb and the cover ring Cb.

[0145] Next, a process for simultaneously removing the edge ring Fb and the cover ring Cb will be described.

[0146] First, the application of a DC voltage to the electrode 109 provided on the electrostatic chuck 502 is stopped, and the edge ring Fb is released from the chucking state.

[0147] Next, all of the lift pins 504 are raised, and the edge ring Fb is transferred from the wafer support table 500 to the upper ends of the lift pins 504. Thereafter, all of the lift pins 504 continue to be raised, and the cover ring Cb is transferred from the wafer support table 500 to the cover ring support portions 504b of the lift pins 504.

[0148] Next, the transfer arm 71 is inserted through a load / unload port (not shown) into the reduced pressure plasma processing chamber 100. Then, the transfer arm 71 is moved between the annular member mounting surface of the wafer support stage 500 and the cover ring Cb supported by the cover ring support portion 504b of the lift pins 504. This results in a state similar to that shown in FIG.

[0149] Next, all the lift pins 504 are lowered, and the covering ring Cb is transferred from the covering ring support parts 504b to the transport arm 71. This results in a state similar to that shown in FIG. 23. Thereafter, all the lift pins 504 continue to be lowered, and the edge ring Fb is transferred from the upper ends of the lift pins 504 to the covering ring Cb held by the transport arm 71. This results in a state similar to that shown in FIG. 22. Next, the transport arm 71 is extracted from the plasma processing chamber 100, and the edge ring Fb and the covering ring Cb are carried out to the outside of the processing module 60. This completes the series of steps for simultaneously removing the edge ring Fb and the cover ring Cb.

[0150] Next, an example of a process for removing the edge ring Fb alone will be described with reference to Figures 25 to 27. Figures 25 to 27 are diagrams showing the state around the wafer support table 500 during the above process. First, the application of a DC voltage to the electrode 109 provided on the electrostatic chuck 502 is stopped, and the edge ring Fb is released from the chucking state.

[0151] 25, all of the lift pins 504 are raised, and the edge ring Fb is transferred from the wafer support stand 500 to the upper ends of the lift pins 504. At this time, the lift pins 504 are raised to a range in which the covering ring Cb is not transferred from the wafer support stand 500 to the covering ring support parts 504b of the lift pins 504, or to a range in which the height position of the covering ring Cb transferred to the covering ring support parts 504b is not higher than the height position of the transfer arm 71 in the plasma processing chamber 100.

[0152] Next, the transfer arm 71 is inserted through a load / unload port (not shown) into the reduced pressure plasma processing chamber 100. Then, as shown in FIG. 26 , the transfer arm 71 is moved between the annular member mounting surface and cover ring Cb of the wafer support stage 500 and the edge ring Fb supported on the upper ends of the lift pins 504.

[0153] 27, all of the lift pins 504 are lowered, and the edge ring Fb is transferred from the upper ends of the lift pins 504 to the transfer arm 71. Then, the transfer arm 71 is extracted from the plasma processing chamber 100, and the edge ring Fb is carried out alone to the outside of the processing module 60. This completes the series of processes for removing the edge ring Fb alone.

[0154] Next, an example of a process for attaching the edge ring Fb alone will be described. First, the transfer arm 71 holding the edge ring Fb alone is inserted through a load / unload port (not shown) into the reduced-pressure plasma processing chamber 100 of the processing module 60 to be attached. Then, the edge ring Fb alone is transferred by the transfer arm 71 above the annular member mounting surface of the wafer support stage 500 and the cover ring Cb mounted on the annular member mounting surface. This results in the same state as in FIG. 27.

[0155] Next, all the lift pins 504 are raised, and the edge ring Fb is transferred from the transport arm 71 to the upper ends of the lift pins 504 that have passed through the through holes Cb2 of the cover ring Cb. At this time, the upper ends of the lift pins 504 fit into the recesses Fb2 provided in the bottom surface of the outer periphery of the edge ring Fb, and the edge ring Fb is positioned relative to the lift pins 504 by the recesses Fb2a that form the recesses Fb2 and the convex surfaces 504a of the lift pins 504. This results in a state similar to that shown in FIG. The lifting pins 504 are raised to a range in which the cover ring Cb is not transferred from the wafer support base 500 to the cover ring support portion 504b of the lifting pins 504, or to a range in which the cover ring Cb transferred to the cover ring support portion 504b does not interfere with the transport arm 71.

[0156] Then, the transfer arm 71 is removed from the plasma processing chamber 100 and the lift pins 504 are lowered, whereby the edge ring Fb is placed on the annular member mounting surface of the wafer support table 500. Thereafter, a DC voltage is applied from a DC power supply (not shown) to the electrode 109 provided on the electrostatic chuck 502, and the edge ring Fb is attracted and held by the electrostatic force generated thereby. This completes the series of steps for attaching the edge ring Fb alone.

[0157] According to this embodiment, the edge ring Fb and the cover ring Cb can be replaced at the same time, which shortens the time required for replacing them. In addition, there is no need to provide a mechanism for lifting and lowering the edge ring Fb and a mechanism for lifting and lowering the cover ring Cb separately, which reduces costs and saves space.

[0158] Furthermore, according to this embodiment, it is possible to selectively replace the edge ring Fb and the cover ring Cb simultaneously or replace the edge ring Fb alone. In either case, at least the edge ring Fb can be positioned and placed on the wafer support table 500 regardless of its transfer accuracy.

[0159] In this embodiment, if only the edge ring Fb of the edge ring Fb and the cover ring Cb has been removed from the wafer support table 500, then only the cover ring Cb can be supported by the lift pins 504, as shown in Fig. 28. If only the cover ring Cb can be supported by the lift pins 504, then the lift pins 504 and the transport arm 71 can cooperate to attach and remove the cover ring Cb alone.

[0160] 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. In addition, elements in different embodiments can be combined to form other embodiments.

[0161] In addition to the above embodiment, the following supplementary notes are disclosed. [Appendix 1] a substrate mounting surface on which a substrate is mounted; an annular member mounting surface on which an annular member is mounted so as to surround the substrate held on the substrate mounting surface; Three or more lift pins configured to be protruding from the annular member mounting surface and lifting and lowering the pins so that the amount of protrusion from the annular member mounting surface can be adjusted; a lifting mechanism for lifting the lift pins, a recess formed of an upwardly recessed surface is provided at a position on the bottom surface of the annular member corresponding to each of the lift pins, The substrate support base has a curvature at the upper end of the lift pin that is greater than the curvature of the recess. [Appendix 2] 2. The substrate support table of claim 1, wherein, in a plan view, an opening of the recess is larger than a transport error of the annular member above the annular member mounting surface. [Appendix 3] 3. The substrate support table according to claim 1 or 2, wherein the lifting mechanism independently raises and lowers each of the lifting pins. [Explanation of symbols]

[0162] 70 Transport Equipment 71 Transport Arm 101 Wafer support table 104a Top side 104b Top surface 107 Lifting pin 107a Convex 114 Lifting mechanism 160 Lifting pin 161 Upper end 200 Wafer support stand 203a Top side 205 Lifting pin 205a Convex 300 Wafer support stand 400 Wafer Support 402a top side 403a top side 405 Lifting pin 405a Convex C. Covering C1 recess C1a concave Ca covering Ca2 recess Ca2a concave F Edge Ring F1 recess F1a concave Fa Edge Ring W wafer

Claims

[Claim 1] a substrate mounting surface on which a substrate is mounted; an annular member mounting surface on which an annular member is mounted, the annular member being arranged so as to surround the substrate held on the substrate mounting surface; three or more lifters configured to be protruding from the annular member mounting surface and raised and lowered so as to adjust the amount of protrusion from the annular member mounting surface; A lifting mechanism for lifting and lowering the lifter, a recessed portion recessed upward is provided at a position on a bottom surface of the annular member corresponding to each of the lifters, When viewed from above, the recess is larger than the conveyance accuracy of the annular member above the annular member mounting surface and is larger than an upper end of the lifter, The upper end of the lifter is formed to be gradually tapered upward, The recess is formed so as to become gradually narrower toward the top, the annular member is both an edge ring disposed adjacent to the substrate placed on the substrate placement surface, and a cover ring covering an outer surface of the edge ring, the recess is formed in a bottom surface of the edge ring of the edge ring and the cover ring; the cover ring has a through hole through which the lifter is inserted and which reaches the recess of the edge ring, The lifter has an edge ring support portion at an upper end thereof that engages with the recess of the edge ring and supports the edge ring, and a cover ring support portion below the edge ring support portion that supports the cover ring.

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