Plasma processing equipment

Abstract

The present invention relates to a plasma processing apparatus. A technique for avoiding process variations caused by cover ring wear is provided. A plasma processing apparatus according to an exemplary embodiment includes a mounting table, a focus ring, a cover ring, a conductive ring, and a high-frequency power supply. The conductive focus ring is mounted on the mounting table. The conductive ring is mounted on the cover ring. A first side surface located on the outer periphery of the focus ring and a second side surface located on the inner periphery of the conductive ring are opposed to each other and spaced apart.

Description

Technical Field

[0001] Illustrative embodiments of the present disclosure relate to a plasma processing apparatus. Background Art

[0002] For example, as disclosed in Patent Document 1, a plasma processing apparatus for substrate processing may include a focus ring and a cover ring. By placing a conductive focus ring around a semiconductor substrate, the discontinuity of the bias potential at the substrate's edge is mitigated, thereby improving plasma processing uniformity. A quartz cover ring is provided around the focus ring (also known as an edge ring). The outer circumference of the focus ring is covered by the cover ring.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2018-206913 Summary of the Invention

[0004] Problems to be solved by the invention

[0005] The cover ring, made of quartz or other materials, covering the outer side of the focus ring wears out over time due to sputtering from plasma ions and other sources. Because the cover ring wears out particularly near the focus ring, as the cover ring wears out, the outer side of the focus ring covered by the cover ring becomes exposed to the plasma. This changes the area of ​​the focus ring that functions as a cathode. Specifically, when the outer side of the focus ring is covered by the cover ring, the top surface of the focus ring functions as a cathode. In contrast, when the cover ring wears out and the outer side of the focus ring is exposed, the outer side of the focus ring also functions as a cathode. Consequently, depending on whether the cover ring wears out or not, process variations such as tilting of the substrate end may occur. The present disclosure provides a technique for suppressing process variations caused by cover ring wear.

[0006] Solutions for solving problems

[0007] In an exemplary technical solution, a plasma processing apparatus is provided. The plasma processing apparatus includes a carrier, a focusing ring, a cover ring, a conductive ring, and a high-frequency power supply. The carrier includes a substrate carrier portion for mounting a substrate and a peripheral portion surrounding the substrate carrier portion. The focusing ring is mounted on the peripheral portion of the carrier and is conductive. The cover ring surrounds the outer periphery of the carrier and is composed of a dielectric. The conductive ring is mounted on the cover ring. The high-frequency power supply is combined with the carrier. A first surface located on the outer periphery of the focusing ring and a second surface located on the inner periphery of the conductive ring are opposed to each other and separated. The cover ring has a separation portion that separates the focusing ring and the conductive ring.

[0008] Effects of the Invention

[0009] According to the present disclosure, it is possible to provide a technique for suppressing process variations caused by loss of the cover ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 FIG. 1 is a diagram showing an example of the structure of a plasma processing apparatus according to an exemplary embodiment.

[0011] Figure 2 This is a diagram showing an example of the structure of a conductive ring according to an exemplary embodiment.

[0012] Figure 3 This is a diagram showing another example of the structure of a conductive ring according to an exemplary embodiment.

[0013] Figure 4 This is a diagram showing an example of the structure of a conductive ring according to an exemplary embodiment.

[0014] Figure 5 It is a diagram showing changes in the structure of the inner circumferential lower surface of the conductive ring and the structure of the separation portion.

[0015] Figure 6 This is a diagram showing another example of the structure of a conductive ring according to an exemplary embodiment.

[0016] Figure 7 This is a diagram showing another example of the structure of a conductive ring according to an exemplary embodiment.

[0017] Figure 8 This is a diagram showing another example of the structure of a conductive ring according to an exemplary embodiment. DETAILED DESCRIPTION

[0018] Various exemplary embodiments are described below. In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a carrier, a focus ring, a cover ring, a conductive ring, and a high-frequency power supply. The carrier includes a substrate carrier portion for mounting a substrate and a peripheral portion surrounding the substrate carrier portion. The focus ring is mounted on the peripheral portion of the carrier and is conductive. The cover ring surrounds the outer periphery of the carrier and is made of a dielectric. The conductive ring is mounted on the cover ring. The high-frequency power supply is combined with the carrier. A first surface located on the outer periphery of the focus ring and a second surface located on the inner periphery of the conductive ring are opposed to and separated from each other. The cover ring has a separation portion that separates the focus ring and the conductive ring. A first side surface located on the outer periphery of the focus ring and a second side surface located on the inner periphery of the conductive ring are opposed to and separated from each other. The focus ring functions as a cathode during plasma processing. The electrically floating conductive ring is arranged so as to be opposed to the outer periphery of such a focus ring.

[0019] In an exemplary embodiment, the inner peripheral portion of the focus ring is supported by the peripheral edge portion of the mounting table, and the outer peripheral portion of the focus ring covers the inner peripheral upper surface of the cover ring.

[0020] In an exemplary embodiment, the first surface is an outer peripheral side surface of the focus ring, and the second surface is an inner peripheral side surface of the conductive ring.

[0021] In an exemplary embodiment, the first surface is the lower surface of the outer periphery of the focus ring, and the second surface is the upper surface of the inner periphery of the conductive ring.

[0022] In an exemplary embodiment, the first surface is the outer peripheral upper surface of the focus ring, and the second surface is the inner peripheral lower surface of the conductive ring.

[0023] In an exemplary embodiment, the outer peripheral side surface of the focus ring and the inner peripheral side surface of the conductive ring are opposed to and separated from each other.

[0024] In an exemplary embodiment, an area of ​​the inner peripheral upper surface of the conductive ring facing the outer peripheral lower surface of the focus ring is larger than an area of ​​the inner peripheral side surface of the conductive ring facing the outer peripheral side surface of the focus ring.

[0025] In an exemplary embodiment, a gap between an outer peripheral lower surface of the focus ring and an inner peripheral upper surface of the conductive ring is narrower than a gap between an outer peripheral side surface of the focus ring and an inner peripheral side surface of the conductive ring.

[0026] In an exemplary embodiment, the focus ring and the conductive ring are capacitively coupled at the first surface and the second surface.

[0027] In an exemplary embodiment, the distance between the first surface and the second surface is greater than 0 and smaller than the thickness of the focus ring.

[0028] In an exemplary embodiment, the inner peripheral lower surface of the conductive ring is located below the outer peripheral lower surface of the focus ring.

[0029] In one exemplary embodiment, the separation portion is a groove formed on the surface of the cover ring, and the inner circumferential lower surface of the conductive ring is accommodated in the groove.

[0030] In one exemplary embodiment, the separation portion is a step portion formed on the surface of the cover ring and configured so that the inner peripheral side surface of the conductive ring abuts against it.

[0031] In an exemplary embodiment, the conductive ring is arranged such that the outer periphery of the conductive ring is located inside the outer periphery of the cover ring. The upper surface of the outer periphery of the cover ring is exposed to the plasma processing space.

[0032] In one exemplary embodiment, the cover ring is constructed from a plurality of dielectric components.

[0033] In an exemplary embodiment, the substrate mounting portion and the peripheral portion are formed of an electrostatic chuck.

[0034] In one exemplary embodiment, the substrate placement portion is formed by an electrostatic chuck, and the peripheral portion is formed by a base of a placement table.

[0035] In an exemplary embodiment, the conductive ring has an inclined portion between an upper surface of the conductive ring and an inner peripheral side surface of the conductive ring.

[0036] In an exemplary embodiment, the conductive ring is made of silicon or silicon carbide, and the cover ring is made of quartz.

[0037] Hereinafter, various exemplary embodiments will be described in detail with reference to the accompanying drawings, wherein the same or corresponding parts are denoted by the same reference numerals in the respective drawings.

[0038] A plasma processing apparatus 1 according to an exemplary embodiment includes a chamber 10. Chamber 10 defines an internal space 12c. Chamber 10 includes a chamber body 12. Chamber body 12 is generally cylindrical. The material of chamber body 12 can be, for example, aluminum. A corrosion-resistant film is provided on the inner wall surface of chamber body 12. The film can be made of a ceramic such as aluminum oxide or yttrium oxide.

[0039] A passage 12p is formed in a side wall of the chamber body 12. The substrate W is transported between the internal space 12c and the outside of the chamber 10 via the passage 12p. The passage 12p is opened and closed by a gate valve 12g provided along the side wall of the chamber body 12.

[0040] A cylindrical portion 28 is provided at the bottom of the chamber body 12. The cylindrical portion 28 may be made of an insulating material and has a substantially cylindrical shape. The cylindrical portion 28 extends upward from the bottom of the chamber body 12 within the internal space 12c.

[0041] Within the internal space 12c, the support portion 15 extends upward from the bottom of the chamber body 12 along the inner side of the substantially cylindrical tubular portion 28. The support portion 15 has a substantially cylindrical shape. The material of the support portion 15 can be an insulating material such as ceramic. A mounting table 16 is mounted on the support portion 15. The mounting table 16 is supported by the support portion 15. The mounting table 16 is configured to support the substrate W within the internal space 12c.

[0042] The mounting table 16 is provided on the support portion 15. The mounting table 16 includes a mounting portion 31, a base 18, and an electrode plate 21.

[0043] The mounting portion 31 includes a substrate mounting portion 31a for mounting a substrate W and a peripheral portion 31b surrounding the substrate mounting portion 31a. A conductive focus ring FR is mounted on the peripheral portion 31b. The conductive ring DR is placed concentrically on the cover ring CR along the outer periphery OPc of the focus ring FR. The mounting portion 31 may also be formed by an electrostatic chuck 20.

[0044] The cover ring CR is provided on the cylindrical portion 28. The cover ring CR is an insulator and extends along the outer circumference of the mounting table 16. The cover ring CR is provided so as to surround the outer circumference of the mounting portion 31 when viewed from above (from the upper electrode 30 side). The cover ring CR is made of an insulating material, such as ceramics such as quartz or alumina. The cover ring CR can be composed of multiple dielectric components.

[0045] The conductive ring DR is positioned above the cover ring CR. The conductive ring DR surrounds the focus ring FR when viewed from above the mounting portion 31. The conductive ring DR is a generally annular plate formed from a conductive material. Examples of the material for the conductive ring DR include silicon (Si) and silicon carbide (SiC).

[0046] The electrode plate 21 is formed of a conductive material such as aluminum and has a substantially disk shape. The base 18 is provided on the electrode plate 21. The base 18 is formed of a conductive material such as aluminum and has a substantially disk shape. The base 18 is electrically connected to the electrode plate 21 and functions as a lower electrode.

[0047] The electrostatic chuck 20 is provided on the base 18 as a loading portion 31. The substrate W is loaded on the upper surface of the electrostatic chuck 20. The electrostatic chuck 20 has a main body and an electrode. The main body of the electrostatic chuck 20 is roughly disc-shaped. The material of the main body of the electrostatic chuck 20 is a dielectric. The electrode of the electrostatic chuck 20 is a film-shaped electrode and is provided in the main body of the electrostatic chuck 20. The electrode of the electrostatic chuck 20 is connected to the DC power supply 20p via the switch 20s. When a voltage from the DC power supply 20p is applied to the electrode of the electrostatic chuck 20, an electrostatic attraction is generated between the electrostatic chuck 20 and the substrate W. The substrate W is held on the electrostatic chuck 20 by this electrostatic attraction.

[0048] The focus ring FR is arranged on the peripheral portion 31b so as to surround the outer periphery of the substrate W placed on the substrate placement portion 31a. The focus ring FR improves the in-plane uniformity of the plasma processing performed on the substrate W. The focus ring FR has a generally annular plate shape and is formed from a conductive material. For example, the focus ring FR can be made of silicon (Si) or silicon carbide (SiC).

[0049] A flow path 18f is provided within the base 18. A heat exchange medium (e.g., refrigerant) is supplied to the flow path 18f via a pipe 23a from a cooler unit (not shown) located outside the chamber 10. The heat exchange medium supplied to the flow path 18f is returned to the cooler unit via a pipe 23b. In the plasma processing apparatus 1, the temperature of the substrate W placed on the electrostatic chuck 20 can be adjusted by heat exchange between the heat exchange medium and the base 18.

[0050] The plasma processing apparatus 1 is provided with a gas supply line 25. The gas supply line 25 supplies a heat transfer gas (eg, He gas) from a heat transfer gas supply mechanism to a space between the upper surface of the electrostatic chuck 20 and the back surface of the substrate W.

[0051] The plasma processing apparatus 1 further includes an upper electrode 30. The upper electrode 30 is disposed above the mounting table 16. The upper electrode 30 is supported on the upper portion of the chamber body 12 by a member 32. The member 32 can be made of an insulating material. The upper electrode 30 and the member 32 seal the upper opening of the chamber body 12.

[0052] The upper electrode 30 may include a top plate 34 and a support 36. The lower surface of the top plate 34 is located on the side of the internal space 12c and defines the internal space 12c. The top plate 34 may be formed of a low-resistance conductor or semiconductor that generates little Joule heat. The top plate 34 has a plurality of gas ejection holes 34a extending through the top plate 34 in the thickness direction.

[0053] The support body 36 supports the top plate 34 so that it can be attached and detached. The material of the support body 36 can be a conductive material such as aluminum. A gas diffusion chamber 36a is provided inside the support body 36. The support body 36 has a plurality of gas holes 36b extending downward from the gas diffusion chamber 36a. The plurality of gas holes 36b are respectively connected to the plurality of gas ejection holes 34a. A gas inlet 36c is formed in the support body 36. The gas inlet 36c is connected to the gas diffusion chamber 36a. The gas inlet 36c is connected to the gas supply pipe 38.

[0054] The gas supply pipe 38 is connected to the valve group 44, the flow controller group 42, and the gas source group 40. The gas source group 40, the valve group 44, and the flow controller group 42 constitute a gas supply unit. The gas source group 40 includes multiple gas sources. The valve group 44 includes multiple on-off valves. The flow controller group 42 includes multiple flow controllers. The multiple flow controllers of the flow controller group 42 are respectively mass flow controllers or pressure-controlled flow controllers. The multiple gas sources of the gas source group 40 are connected to the gas supply pipe 38 via the corresponding on-off valves of the valve group 44 and the corresponding flow controllers of the flow controller group 42.

[0055] A baffle 48 is provided between the cylindrical portion 28 and the side wall of the chamber body 12. The baffle 48 is formed by, for example, forming a corrosion-resistant film (e.g., a film of yttrium oxide) on the surface of a base material formed of aluminum. A plurality of through-holes are formed in the baffle 48. An exhaust port is provided at the bottom of the chamber body 12, below the baffle 48. The exhaust port is connected to an exhaust device 50 via an exhaust pipe 52. The exhaust device 50 includes a pressure regulating valve and a vacuum pump such as a turbomolecular pump.

[0056] The plasma processing apparatus 1 includes a first high-frequency power supply 62 and a second high-frequency power supply 64. The first high-frequency power supply 62 is a power supply for generating a first high-frequency power. The first high-frequency power has a frequency suitable for generating plasma. The frequency of the first high-frequency power is, for example, a frequency in the range of 27 [MHz] to 100 [MHz]. The first high-frequency power supply 62 is connected to the base 18 via a matching box 66 and an electrode plate 21. The matching box 66 has a circuit for matching the output impedance of the first high-frequency power supply 62 with the impedance of the load side (the base 18 side). In addition, the first high-frequency power supply 62 can also be connected to the upper electrode 30 via the matching box 66.

[0057] The second high-frequency power supply 64 is a power supply that generates a second high-frequency power. The second high-frequency power has a frequency lower than that of the first high-frequency power. When the second high-frequency power is used together with the first high-frequency power, the second high-frequency power is used as a high-frequency power for biasing ions to introduce ions into the substrate W. The frequency of the second high-frequency power is, for example, a frequency in the range of 400 [kHz] to 13.56 [MHz]. The second high-frequency power supply 64 is connected to the base 18 via a matching device 68 and an electrode plate 21. The matching device 68 has a circuit for matching the output impedance of the second high-frequency power supply 64 with the impedance of the load side (base 18 side).

[0058] Alternatively, the second high-frequency power may be used instead of the first high-frequency power, that is, only a single high-frequency power may be used to generate plasma. In this case, the frequency of the second high-frequency power may be greater than 13.56 MHz, such as 40 MHz. The plasma processing apparatus 1 may also not include the first high-frequency power source 62 and the matching unit 66.

[0059] In plasma processing apparatus 1, gas is supplied from a gas supply unit into internal space 12c to generate plasma. Supplying at least one of first and second high-frequency power generates a high-frequency electric field between upper electrode 30 and base 18 (lower electrode). Plasma is generated using this generated high-frequency electric field.

[0060] The plasma processing apparatus 1 may further include a control unit MC. The control unit MC may be a computer including a processor, a storage unit such as a memory, an input device, a display device, a signal input / output interface, etc. The control unit MC controls various components of the plasma processing apparatus 1 .

[0061] In the control unit MC, an operator can use an input device to input commands and other operations to manage the plasma processing apparatus 1. Furthermore, the control unit MC can use a display device to visually display the operating status of the plasma processing apparatus 1. Furthermore, the storage unit stores control programs and process data. The processor executes the control programs to perform various processes in the plasma processing apparatus 1. The processor executes the control programs and controls various components of the plasma processing apparatus 1 according to the process data.

[0062] Reference Figure 2 ,illustrate Figure 1 The structure of the region ER of the mounting table 16 is shown. In particular, the structures of the conductive ring DR and the focus ring FR are described in detail.

[0063] exist Figure 2 In the example shown, the cover ring CR is composed of two dielectric members, an inner cover ring CRa and an outer cover ring CRb. Alternatively, the cover ring CR may be composed of one dielectric member or three or more dielectric members.

[0064] The inner peripheral side (inner peripheral portion) of the focusing ring FR is placed on the peripheral portion 31b of the placement portion 31, i.e., the electrostatic chuck 20, and the outer peripheral side (outer peripheral portion) is configured to cover the inner cover ring CRa. The outer peripheral portion of the focusing ring FR may also be placed on the inner cover ring CRa. In order to ensure that the inner peripheral portion of the focusing ring FR is reliably supported by the peripheral portion 31b, the upper surface SFa of the inner cover ring CRa may also be formed to be lower than the upper surface of the peripheral portion 31b, and a gap may be provided between the lower surface of the outer peripheral portion of the focusing ring FR and the upper surface SFa of the inner cover ring CRa. That is, the outer peripheral portion of the focusing ring FR may not be placed on the inner cover ring CRa. The thickness of the main body of the electrostatic chuck 20 is very small compared to the thickness of the inner cover ring CRa. Therefore, the focusing ring FR is coupled to the first high-frequency power supply 62 and the second high-frequency power supply 64 as a high-frequency circuit via the electrostatic chuck 20. In addition, as Figure 3 As shown, a power supply rod SP connected to a DC power supply DC and in contact with the lower surface of the focus ring FR may be arranged in a through hole provided in the inner cover ring CRa, so that a DC voltage can be applied to the focus ring FR.

[0065] The conductive ring DR is placed on the outer cover ring CRb. Since the outer cover ring CRb is thick, the conductive ring DR is not coupled to the first high-frequency power source 62 and the second high-frequency power source 64 as a high-frequency circuit via the outer cover ring CRb.

[0066] The outer cover ring CRb has an inner upper surface SFc and an outer upper surface SFd. The inner side of the outer cover ring CRb is more susceptible to wear than the outer side because it is closer to the focus ring FR. Figure 2 In the example, the conductive ring DR is arranged so as to cover only the position that is easily worn (the upper surface SFc on the inner peripheral side of the outer cover ring CRb). That is, the outer periphery OPd of the conductive ring DR is arranged so as to be located inside the outer periphery OPe of the cover ring CR, and the outer peripheral upper surface of the cover ring CR is exposed to the plasma processing space (inner space 12c). However, the conductive ring DR may also be arranged so as to cover the entire upper surface of the outer cover ring CRb. In addition, in Figure 2 In the example shown, the outer peripheral upper surface SFd and the inner peripheral upper surface SFc covered by the conductive ring DR are arranged on the same plane, but they may be arranged not to be on the same plane. For example, the upper surface SFd of the outer cover ring CRb not covered by the conductive ring DR may be higher than the upper surface SFb of the conductive ring DR, or they may be at the same height.

[0067] like Figure 2 As shown, a gap AS is provided between the focus ring FR and the conductive ring DR. More specifically, a first side surface SSa located at the outer periphery OPc of the focus ring FR and a second side surface SSb located at the inner periphery IPb of the conductive ring DR face each other and are spaced apart. The inner lower surface ILSb of the conductive ring DR is located below the outer lower surface ILSa of the focus ring FR.

[0068] exist Figure 2 In the example shown, the area of ​​the second side surface SSb is smaller than the area of ​​the top surface SFb of the conductive ring DR. The top surface SFb of the conductive ring DR is higher than the top surface of the focus ring FR. In other words, the thickness of the inner periphery IPb of the conductive ring DR is greater than the thickness of the outer periphery OPc of the focus ring FR.

[0069] The distance GA between the first side surface SSa and the second side surface SSb is the width of the gap AS. As described later, the first side surface SSa and the second side surface SSb function as a capacitor. Therefore, it is desirable that the distance GA is greater than 0 and smaller than the thickness SH of the focus ring FR.

[0070] The cover ring CR further includes a separation portion DT that separates the first side surface SSa of the focus ring FR from the second side surface SSb of the conductive ring DR.

[0071] exist Figure 2In the illustrated example, the inner circumferential upper surface SFc of the outer cover ring CRb is lower than the upper surface SFa of the inner cover ring CRa, and a step is provided between the inner and outer cover rings CRa and CRb, thereby forming a separation portion DT. Because the step abuts the second side surface SSb of the conductive ring DR, the second side surface SSb of the conductive ring DR does not contact the first side surface SSa of the focus ring FR. In other words, the provision of the separation portion DT prevents the first and second side surfaces SSa and SSb from contacting each other and thus preventing them from functioning as a capacitor.

[0072] In the mounting table 16 of the above-described structure, the conductive ring DR is placed on the cover ring CR. Because the cover ring CR is thicker than the main body of the electrostatic chuck 20, the conductive ring DR is not coupled to the first and second high-frequency power supplies 62 and 64 as the high-frequency circuit 64 via the cover ring CR. Furthermore, the first side surface SSa on the outer periphery OPc of the focus ring FR and the second side surface SSb on the inner periphery IPb of the conductive ring DR face each other and are separated. Consequently, the first side surface SSa and the second side surface SSb function as capacitors. In other words, the focus ring FR and the conductive ring DR are capacitively coupled at the first and second side surfaces SSa and SSb. The first side surface SSa is located at the outer periphery OPc of the focus ring FR. When high-frequency power is applied to the base 18, electrostatic induction is generated within the conductive ring DR by the positive or negative charge present on the first side surface SSa. Consequently, charges of equal magnitude and opposite magnitude to those accumulated on the second side surface SSb of the conductive ring DR are attracted by the plasma potential and accumulate on the upper surface SFb of the conductive ring DR. Because the area of ​​top surface SFb is larger than that of second side surface SSb, the amount of charge per unit area on top surface SFb is smaller than that on second side surface SSb. Consequently, the potential of the conductive ring DR is lower than that of the focus ring FR, reducing the acceleration of ions in the plasma toward the conductive ring DR. Consequently, the conductive ring DR (i.e., the area outside the focus ring FR) is less susceptible to sputtering.

[0073] The conductive ring DR is positioned to cover a portion of the cover ring CR that is prone to wear and tear. It is made of a material with higher sputtering resistance than the cover ring CR. Furthermore, since the acceleration of ions toward the conductive ring DR is reduced, the conductive ring DR itself is less susceptible to sputtering. This reduces changes in the cathode area of ​​the focus ring FR due to wear and tear of the cover ring CR around the outer periphery of the focus ring FR. Consequently, process variations such as tilting at the substrate end can be suppressed.

[0074] Furthermore, by adjusting the area of ​​the upper surface SFb of the conductive ring DR, the potential of the upper surface SFb of the conductive ring DR can be adjusted.

[0075] Furthermore, the conductive ring DR is disposed opposite the first side surface SSa of the focus ring FR. Because an object (the conductive ring DR) is present to the side of the first side surface SSa of the focus ring FR, ions directed toward the first side surface SSa are blocked by the conductive ring DR. Consequently, the focus ring FR is less susceptible to sputtering from the first side surface SSa, thereby suppressing wear of the focus ring FR.

[0076] In addition, Figure 2 In the example shown, the electrostatic chuck 20 constitutes the substrate mounting portion 31a and the peripheral portion 31b for mounting the focus ring FR, but the present invention is not limited thereto. The electrostatic chuck of the substrate mounting portion 31a and the electrostatic chuck of the peripheral portion 31b may also be provided independently. Figure 4 As shown, only the substrate mounting portion 31a may be provided as the electrostatic chuck 20, and the peripheral portion 31b may be formed using the base 18. Furthermore, not only the inner circumference of the focus ring FR but also the entire focus ring may be placed on the peripheral portion 31b. The peripheral portion 31b may also be formed lower than the substrate mounting portion 31a to form a stepped portion.

[0077] In addition, Figure 2 In the example shown, the upper surface SFc on the inner peripheral side of the outer cover ring CRb is configured to be lower than the upper surface SFa of the inner cover ring CRa, thereby forming a separation portion DT, but the present invention is not limited thereto. Figure 5 As shown, a concave groove may be provided in the cover ring CR on which the conductive ring DR is placed, and the inner circumferential lower surface ILSb of the conductive ring DR may be provided in a convex shape facing downward. In this case, the inner circumferential lower surface ILSb of the conductive ring DR is accommodated in the concave portion (groove) of the cover ring CR. The convex inner circumferential lower surface ILSb is embedded in the concave groove, thereby stably maintaining the position of the conductive ring DR relative to the cover ring CR. In addition, Figure 5 In the embodiment, the outer cover ring CRb is provided with a groove as a separation portion DT, but the groove may be provided on the inner cover ring CRa side. In this case, the inner peripheral side of the conductive ring DR is placed on the inner cover ring CRa, and the outer peripheral side of the conductive ring DR is placed on the outer cover ring CRb. Figure 5 In the embodiment, the upper surface SFa of the cover ring CR on which the focus ring FR is placed and the upper surface SFc of the cover ring CR on which the conductive ring DR is placed are configured to be at the same height, but they may be configured to be at different heights. For example, the upper surface SFc of the cover ring CR on which the conductive ring DR is placed may be configured to be higher than the upper surface SFa of the cover ring CR on which the focus ring FR is placed.

[0078] In addition, Figure 2 In the example shown, the first side surface SSa of the focus ring FR and the second side surface SSb of the conductive ring DR are opposed to each other and separated from each other, thereby functioning as a capacitor, but the present invention is not limited thereto. Figure 6As shown, the outer peripheral lower surface of the focus ring FR and the inner peripheral upper surface of the conductive ring DR may be configured to face each other and be spaced apart. Figure 6 The lower portion of the inner circumference of the conductive ring DR shown in FIG. The upper surface of the protruding lower inner circumference of the conductive ring DR and the lower surface of the focus ring FR are opposed to and spaced apart from each other. Furthermore, the first side surface SSa of the focus ring FR and the second side surface SSb, which is the side surface of the upper inner circumference of the conductive ring DR, are opposed to and spaced apart from each other.

[0079] The inner circumferential upper surface SFc of the outer cover ring CRb is lower than the upper surface SFa of the inner cover ring CRa, forming a step portion, or separation portion DT, between the inner and outer cover rings CRa and CRb. The third side surface SSc, the side surface of the lower inner circumference of the conductive ring DR, abuts the step portion (the outer circumferential side surface of the inner cover ring CRa). Therefore, the second side surface SSb, the side surface of the upper inner circumference of the conductive ring DR, does not contact the first side surface SSa of the focus ring FR. Furthermore, the upper surface SFa of the inner cover ring CRa is positioned higher than the upper surface of the lower inner circumference of the conductive ring DR. Therefore, since the lower surface of the focus ring FR abuts the upper surface SFa of the inner cover ring CRa, the upper surface of the lower inner circumference of the conductive ring DR does not contact the lower surface of the focus ring.

[0080] exist Figure 6 In the example shown, not only the first side surface SSa and the second side surface SSb, but also the outer peripheral lower surface of the focus ring FR and the lower inner peripheral upper surface of the conductive ring DR can function as capacitors. This can increase the capacitance between the focus ring FR and the conductive ring DR.

[0081] The distance GB between the outer peripheral lower surface of the focus ring FR and the lower inner peripheral upper surface of the conductive ring DR can also be configured to be smaller than the distance GA between the first side surface SSa and the second side surface SSb. Because the distance GB is smaller than the distance GA, the capacitance between the outer peripheral lower surface of the focus ring FR and the lower inner peripheral upper surface of the conductive ring DR is larger than the capacitance between the first side surface SSa and the second side surface SSb. Therefore, even if the areas of the first side surface SSa and the second side surface SSb change due to loss in the focus ring FR and the conductive ring DR, the change in capacitance between the focus ring FR and the conductive ring DR can be reduced. Furthermore, since the distance GA between the first side surface SSa and the second side surface SSb can be increased, it is possible to prevent the gap AS from being clogged by deposits and failing to function as a capacitor (or causing a significant change in capacitance).

[0082] Alternatively, the area of ​​the lower inner circumferential upper surface of the conductive ring DR that faces the outer circumferential lower surface of the focus ring FR may be larger than the area of ​​the inner circumferential side surface of the conductive ring DR that faces the outer circumferential side surface of the focus ring FR. This increases the capacitance between the outer circumferential lower surface of the focus ring FR and the lower inner circumferential upper surface of the conductive ring DR, thereby reducing changes in the capacitance between the focus ring FR and the conductive ring DR.

[0083] like Figure 6 As shown in the example shown, a sloped portion may be formed between the inner peripheral side surface and the upper surface of the conductive ring DR. Providing the sloped portion can mitigate the height difference between the upper surface of the focus ring FR and the upper surface of the conductive ring DR, thereby mitigating the discontinuity of the sheath formed above the conductive ring DR and the focus ring FR.

[0084] exist Figures 2 to 6 In the illustrated example, the upper surface SFb of the conductive ring DR is higher than the upper surface of the focus ring FR, but the present invention is not limited thereto. The upper surface SFb of the conductive ring DR may be configured to be at the same height as the upper surface of the focus ring FR, or may be configured to be lower than the upper surface of the focus ring FR.

[0085] exist Figure 6 In the example shown, the outer peripheral lower surface of the focus ring FR and the inner peripheral upper surface of the conductive ring DR are opposed to each other and separated. Figure 7 As shown, the outer peripheral upper surface of the focus ring FR and the inner peripheral lower surface of the conductive ring DR may be arranged to face each other and be spaced apart from each other.

[0086] Figure 7 The upper portion of the inner circumference of the conductive ring DR shown in FIG. The lower surface of the protruding upper inner circumference of the conductive ring DR and the upper surface of the focus ring FR face each other and are spaced apart. Furthermore, the first side surface SSa of the focus ring FR and the second side surface SSb, which is the side surface of the lower inner circumference of the conductive ring DR, face each other and are spaced apart.

[0087] The inner circumferential upper surface SFc of the outer cover ring CRb is lower than the upper surface SFa of the inner cover ring CRa, forming a step portion, or separation portion DT, between the inner and outer cover rings CRa and CRb. The second side surface SSb, or the side surface of the lower inner circumference of the conductive ring DR, abuts against the step portion (the outer circumferential side surface of the inner cover ring CRa). Therefore, the second side surface SSb, or the side surface of the upper inner circumference of the conductive ring DR, does not contact the first side surface SSa of the focus ring FR. Furthermore, the lower surface of the protruding upper inner circumference of the conductive ring DR is positioned higher than the upper surface of the outer circumference of the focus ring. Consequently, the lower surface of the upper inner circumference of the conductive ring DR does not contact the upper surface of the focus ring.

[0088] and Figure 6 Similarly to the example shown, a configuration may be employed in which the distance GC between the outer peripheral upper surface of the focus ring FR and the upper inner peripheral lower surface of the conductive ring DR is smaller than the distance GA between the first side surface SSa and the second side surface SSb. Alternatively, the area of ​​the upper inner peripheral lower surface of the conductive ring DR facing the outer peripheral upper surface of the focus ring FR may be larger than the area of ​​the inner peripheral side surface of the conductive ring DR facing the outer peripheral side surface of the focus ring FR.

[0089] exist Figure 7 In the example shown, the space AS is covered by the upper inner peripheral portion of the conductive ring DR. Therefore, it is possible to suppress the space AS from being clogged with deposits and failing to function as a capacitor (or causing a significant change in capacitance).

[0090] exist Figure 6 and Figure 7 In the illustrated example, the outer peripheral lower surface (upper surface) of the focus ring FR and the inner peripheral upper surface (lower surface) of the conductive ring DR are opposed to and spaced apart from each other, and the first side surface SSa of the focus ring FR and the second side surface SSb of the conductive ring DR are opposed to and spaced apart from each other. However, only the outer peripheral lower surface (upper surface) of the focus ring FR and the inner peripheral upper surface (lower surface) of the conductive ring DR may be opposed to and spaced apart from each other.

[0091] exist Figures 2 to 7 In the illustrated example, the focus ring FR is arranged so that its outer circumference (outer periphery) covers the inner cover ring CRa. However, the entire focus ring FR may be placed on the electrostatic chuck 20 or the base 18. In other words, not only the inner circumference (inner periphery) but also the outer circumference (outer periphery) of the focus ring FR may be placed on the electrostatic chuck 20 or the base 18, which serves as the peripheral edge 31b of the placement portion 31.

[0092] exist Figure 8 In the example shown, only the outer peripheral upper surface of the focus ring FR and the inner peripheral lower surface of the conductive ring DR are opposed to each other and separated from each other.

[0093] The inner periphery of the cover ring CR is placed on the outer periphery of the focus ring FR. The conductive ring DR is placed on the cover ring CR. The inner periphery of the conductive ring DR has a protrusion that protrudes downward, and the lower surface of the protrusion (lower surface of the inner periphery) and the upper surface of the outer periphery of the focus ring FR are opposite to and separated from each other. The conductive ring DR is placed on the cover ring CR, so the upper surface of the cover ring CR abuts against the lower surface of the outer periphery of the conductive ring DR. That is, the upper surface of the cover ring CR becomes the separation portion DT, and the lower surface of the protrusion of the conductive ring DR does not contact the upper surface of the outer periphery of the focus ring FR. In addition, in Figure 8In the example shown, a protrusion protruding downward is formed on the inner periphery of the conductive ring DR, but the protrusion may not be formed as long as sufficient capacitance can be obtained between the lower surface of the inner periphery of the conductive ring DR and the upper surface of the outer periphery of the focus ring.

[0094] Although various exemplary embodiments have been described above, the present invention is not limited to the exemplary embodiments described above, and various omissions, substitutions, and changes are possible. Furthermore, elements of different exemplary embodiments can be combined to form other exemplary embodiments.

[0095] As described above, various exemplary embodiments of the present disclosure have been described in this specification for illustrative purposes. It should be understood that various modifications may be made without departing from the scope and spirit of the present disclosure. Therefore, the various exemplary embodiments disclosed in this specification are not intended to be limiting, and the true scope and spirit are indicated by the claims.

Claims

1. A plasma processing device, wherein: The plasma processing device has: a mounting table having a substrate mounting portion for mounting a substrate and a peripheral portion surrounding the substrate mounting portion; a focusing ring, which is placed on the peripheral portion of the mounting table and has conductivity; a cover ring surrounding the outer periphery of the mounting table and made of a dielectric; a conductive ring placed on the cover ring; as well as A high frequency power supply, which is combined with the mounting table, The first surface located at the outer periphery of the focusing ring and the second surface located at the inner periphery of the conductive ring are opposite to and separated from each other. The cover ring has a separation portion for separating the focus ring and the conductive ring. The first surface is the lower surface of the outer periphery of the focus ring, and the second surface is the upper surface of the inner periphery of the conductive ring. The outer peripheral side surface of the focusing ring and the inner peripheral side surface of the conductive ring are opposed to each other and separated from each other. An area of ​​the inner peripheral upper surface of the conductive ring facing the outer peripheral lower surface of the focus ring is larger than an area of ​​the inner peripheral side surface of the conductive ring facing the outer peripheral side surface of the focus ring.

2. A plasma processing device, wherein: The plasma processing device has: a mounting table having a substrate mounting portion for mounting a substrate and a peripheral portion surrounding the substrate mounting portion; a focusing ring, which is placed on the peripheral portion of the mounting table and has conductivity; a cover ring surrounding the outer periphery of the mounting table and made of a dielectric; a conductive ring placed on the cover ring; as well as A high frequency power supply, which is combined with the mounting table, The first surface located at the outer periphery of the focusing ring and the second surface located at the inner periphery of the conductive ring are opposite to and separated from each other. The cover ring has a separation portion for separating the focus ring and the conductive ring. The first surface is the lower surface of the outer periphery of the focus ring, and the second surface is the upper surface of the inner periphery of the conductive ring. The outer peripheral side surface of the focusing ring and the inner peripheral side surface of the conductive ring are opposed to each other and separated from each other. A gap between an outer peripheral lower surface of the focus ring and an inner peripheral upper surface of the conductive ring is narrower than a gap between an outer peripheral side surface of the focus ring and an inner peripheral side surface of the conductive ring.

3. The plasma processing apparatus according to claim 1 or 2, wherein: The focus ring and the conductive ring are capacitively coupled on the first surface and the second surface.

4. The plasma processing apparatus according to claim 1 or 2, wherein: The distance between the first surface and the second surface is greater than 0 and smaller than the thickness of the focus ring.

5. The plasma processing apparatus according to claim 1 or 2, wherein: The inner peripheral lower surface of the conductive ring is located below the outer peripheral lower surface of the focus ring.

6. The plasma processing apparatus according to claim 1 or 2, wherein: The separation portion is a groove formed on the surface of the cover ring, and the inner circumferential lower surface of the conductive ring is accommodated in the groove.

7. The plasma processing apparatus according to claim 1 or 2, wherein: The separation portion is a step portion formed on the surface of the cover ring and configured to be in contact with the inner peripheral side surface of the conductive ring.

8. The plasma processing apparatus according to claim 1 or 2, wherein: The conductive ring is arranged so that the outer periphery of the conductive ring is located inside the outer periphery of the cover ring. An upper surface of an outer peripheral portion of the cover ring is exposed to the plasma processing space.

9. The plasma processing apparatus according to claim 1 or 2, wherein: The cover ring is composed of a plurality of dielectric components.

10. The plasma processing apparatus according to claim 1 or 2, wherein: The substrate mounting portion and the peripheral portion are formed of an electrostatic chuck.

11. The plasma processing apparatus according to claim 1 or 2, wherein: The substrate mounting portion is formed of an electrostatic chuck, and the peripheral portion is formed of a base of the mounting table.

12. The plasma processing apparatus according to claim 1 or 2, wherein: The conductive ring has an inclined portion between an upper surface of the conductive ring and an inner peripheral side surface of the conductive ring.

13. The plasma processing apparatus according to claim 1 or 2, wherein: The conductive ring is made of silicon or silicon carbide, and the cover ring is made of quartz.

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