Plasma processing apparatus and substrate support base assembly

Abstract

To provide a technique for avoiding a processing fluctuation due to a consumption of a covering.SOLUTION: A plasma processing apparatus to be disclosed, comprises: a plasma processing chamber; a substrate support base; at least one insulation ring, an inner side conductive ring, an outer side conductive ring; and a high-frequency power source. The substrate support base contains a base and an electrostatic chuck, and is arranged into a chamber. The at least one insulation ring is arranged so as to surround the substrate support base. The inner side conductive ring includes an outer side surface, and is arranged on the electrostatic chuck and the at least one insulation ring so as to surround the substrate on the electrostatic chuck. The outer side conductive ring includes an inner side surface that is opposite to a side surface of the inner side conductive ring, and is arranged onto the at least one insulation ring so as to surround the inner side conductive ring without being conducted to the inner side conductive ring. The high-frequency power source is electrically connected to the substrate support base.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Exemplary embodiments of the present disclosure relate to a plasma processing apparatus.

Background Art

[0002] A plasma processing apparatus for performing substrate processing may have a configuration including a focus ring and a cover ring, as disclosed in, for example, Patent Document 1. By disposing a conductive focus ring so as to surround the periphery of a semiconductor substrate, discontinuity of the bias potential at the substrate edge is alleviated, and the uniformity of plasma processing is improved. A quartz cover ring is provided around this focus ring (also called an edge ring). The outer peripheral side surface of the focus ring is covered by the cover ring.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A cover ring made of quartz or the like that covers the outer peripheral side surface of the focus ring can be consumed over time by sputtering caused by ions of the plasma or the like. Since the vicinity of the focus ring side of the cover ring is particularly consumed, as the cover ring is consumed, the outer peripheral side surface of the focus ring that was covered by the cover ring is exposed to the plasma. In such a case, the area of the focus ring as a cathode fluctuates. That is, when the outer peripheral side surface of the focus ring is covered by the cover ring, the upper surface of the focus ring functions as a cathode. On the other hand, when the cover ring is consumed and the outer peripheral side surface of the focus ring is exposed, the outer peripheral side surface of the focus ring also functions as a cathode. Therefore, process variations such as the occurrence of tilting at the substrate edge can occur before and after the consumption of the cover ring. The present disclosure provides a technique for suppressing process variations due to the consumption of the cover ring.

Means for Solving the Problems

[0005] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a plasma processing chamber, a substrate support, at least one insulating ring, an inner conductive ring, an outer conductive ring, and a high-frequency power source. The substrate support includes a base and an electrostatic chuck and is disposed within the chamber. At least one insulating ring is disposed so as to surround the substrate support. The inner conductive ring has an outer surface and is disposed on the electrostatic chuck and at least one insulating ring so as to surround the substrate on the electrostatic chuck. The outer conductive ring has an inner surface facing the side surface of the inner conductive ring and is disposed on at least one insulating ring so as to surround the inner conductive ring without contacting the inner conductive ring. The high-frequency power source is electrically coupled to the substrate support.

Effects of the Invention

[0006] According to the present disclosure, a technique for suppressing process variations due to the consumption of the cover ring can be provided.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

[0008] Hereinafter, various exemplary embodiments will be described. In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a mounting table, a focus ring, a cover ring, a conductive ring, and a high-frequency power source. The mounting table has a substrate mounting portion for mounting a substrate and a peripheral portion surrounding the substrate mounting portion. The focus ring is mounted on the peripheral portion of the mounting table and has conductivity. The cover ring surrounds the outer periphery of the mounting table and is made of a dielectric. The conductive ring is mounted on the cover ring. The high-frequency power source is coupled to the mounting table. A first surface on the outer peripheral portion of the focus ring and a second surface on the inner peripheral portion of the conductive ring face each other and are spaced apart. The cover ring has a separating portion that separates the focus ring and the conductive ring. A first side surface on the outer periphery of the focus ring and a second side surface on the inner periphery of the conductive ring face each other and are spaced apart. The focus ring functions as a cathode during plasma processing. An electrically floating conductive ring is provided so as to face the outer periphery of such a focus ring.

[0009] In one exemplary embodiment, the inner peripheral portion of the focus ring is supported by the peripheral portion of the mounting table, and the outer peripheral portion of the focus ring covers the upper surface of the inner peripheral portion of the cover ring.

[0010] In one exemplary embodiment, the first surface is the side surface of the outer peripheral portion of the focus ring, and the second surface is the side surface of the inner peripheral portion of the conductive ring.

[0011] In one exemplary embodiment, the first surface is the lower surface of the outer peripheral portion of the focus ring, and the second surface is the upper surface of the inner peripheral portion of the conductive ring.

[0012] In one exemplary embodiment, the first surface is the upper surface of the outer peripheral portion of the focus ring, and the second surface is the lower surface of the inner peripheral portion of the conductive ring.

[0013] In one exemplary embodiment, the side surface of the outer peripheral portion of the focus ring and the side surface of the inner peripheral portion of the conductive ring face each other and are spaced apart.

[0014] In one exemplary embodiment, the area of the upper surface of the inner peripheral portion of the conductive ring facing the lower surface of the outer peripheral portion of the focus ring is larger than the area of the side surface of the inner peripheral portion of the conductive ring facing the side surface of the outer peripheral portion of the focus ring.

[0015] In one exemplary embodiment, the gap between the lower surface of the outer peripheral portion of the focus ring and the upper surface of the inner peripheral portion of the conductive ring is narrower than the gap between the side surface of the outer peripheral portion of the focus ring and the side surface of the inner peripheral portion of the conductive ring.

[0016] In one exemplary embodiment, the focus ring and the conductive ring are capacitively coupled on a first surface and a second surface.

[0017] In one exemplary embodiment, the distance between the first surface and the second surface is greater than zero and less than the thickness of the focus ring.

[0018] In one exemplary embodiment, the lower surface of the inner peripheral portion of the conductive ring is located below the lower surface of the outer peripheral portion of the focus ring.

[0019] In one exemplary embodiment, the separation portion is a groove formed on the surface of the cover ring. The lower surface of the inner peripheral portion of the conductive ring is received in the groove.

[0020] In one exemplary embodiment, the separation portion is a stepped portion formed on the surface of the cover ring configured such that the side surface of the inner peripheral portion of the conductive ring abuts thereon.

[0021] In one 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 peripheral portion of the cover ring is exposed to the plasma processing space.

[0022] In one exemplary embodiment, the cover ring is composed of a plurality of dielectric components.

[0023] In one exemplary embodiment, the substrate mounting portion and the peripheral portion are constituted by an electrostatic chuck.

[0024] In one exemplary embodiment, the substrate mounting portion is constituted by an electrostatic chuck, and the peripheral portion is constituted by the base of the mounting table.

[0025] In one exemplary embodiment, the conductive ring has an inclined portion between the upper surface of the conductive ring and the inner peripheral side surface of the conductive ring.

[0026] In one exemplary embodiment, the material of the conductive ring is silicon or silicon carbide. The material of the cover ring is quartz.

[0027] Hereinafter, various exemplary embodiments will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts will be denoted by the same reference numerals.

[0028] A plasma processing apparatus 1 according to one exemplary embodiment includes a chamber 10. The chamber 10 provides an internal space 12c therein. The chamber 10 includes a chamber body 12. The chamber body 12 has a substantially cylindrical shape. The material of the chamber body 12 can be, for example, aluminum. A corrosion-resistant film is provided on the inner wall surface of the chamber body 12. The material of the film can be a ceramic such as aluminum oxide or yttrium oxide.

[0029] A passage 12p is formed in the side wall of the chamber body 12. The substrate W is transported between the internal space 12c and the outside of the chamber 10 through 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.

[0030] A cylindrical portion 28 is provided on the bottom of the chamber body 12. The material of the cylindrical portion 28 can be an insulating material. The cylindrical portion 28 has a substantially cylindrical shape. The cylindrical portion 28 extends upward from the bottom of the chamber body 12 in the internal space 12c.

[0031] Inside the internal space 12c, the support portion 15 extends upward from the bottom of the chamber body 12 along the inner side surface 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 inside the internal space 12c.

[0032] 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.

[0033] The mounting portion 31 includes a substrate mounting portion 31a which is a region for mounting the substrate W, and a peripheral portion 31b which is a region surrounding the substrate mounting portion 31a. A conductive focus ring FR is mounted on the peripheral portion 31b. The conductive ring DR is mounted concentrically on the cover ring CR along the outer periphery OPc of the focus ring FR. The mounting portion 31 may be constituted by an electrostatic chuck 20.

[0034] The cover ring CR is provided on the tubular portion 28. The cover ring CR is an insulator and extends along the outer periphery of the mounting table 16. The cover ring CR is provided so as to surround the outer periphery of the mounting portion 31 when viewed from above the mounting portion 31 (when viewed from the side of the upper electrode 30). The material of the cover ring CR is a material having insulating properties and can be, for example, a ceramic such as quartz or alumina. The cover ring CR can be constituted by a plurality of dielectric components.

[0035] The conductive ring DR is disposed above the cover ring CR. The conductive ring DR is provided so as to surround the focus ring FR when viewed from above the mounting portion 31. The conductive ring DR has a substantially annular plate shape and is formed from a conductive material. The material of the conductive ring DR can be, for example, silicon (Si) or silicon carbide (SiC).

[0036] 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.

[0037] The electrostatic chuck 20 is provided on the base 18 as a mounting portion 31. The substrate W is placed on the upper surface of the electrostatic chuck 20. The electrostatic chuck 20 has a main body and electrodes. The main body of the electrostatic chuck 20 has a substantially disk shape. The material of the main body of the electrostatic chuck 20 is a dielectric. The electrodes of the electrostatic chuck 20 are film-like electrodes and are provided inside the main body of the electrostatic chuck 20. The electrodes of the electrostatic chuck 20 are connected to a DC power supply 20p via a switch 20s. When a voltage from the DC power supply 20p is applied to the electrodes of the electrostatic chuck 20, an electrostatic attraction force is generated between the electrostatic chuck 20 and the substrate W. By that electrostatic attraction force, the substrate W is held by the electrostatic chuck 20.

[0038] The focus ring FR is disposed at the peripheral edge portion 31b so as to surround the outer periphery of the substrate W placed on the substrate mounting portion 31a. The focus ring FR improves the in-plane uniformity of the plasma treatment with respect to the substrate W. The focus ring FR has a substantially annular plate shape and is formed of a conductive material. The material of the focus ring FR can be, for example, silicon (Si) or silicon carbide (SiC).

[0039] A flow path 18f is provided inside the base 18. A heat exchange medium (for example, a refrigerant) is supplied to the flow path 18f from a chiller unit (not shown) provided outside the chamber 10 via a pipe 23a. The heat exchange medium supplied to the flow path 18f is returned to the chiller 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 the heat exchange between the heat exchange medium and the base 18.

[0040] The plasma processing apparatus 1 is provided with a gas supply line 25. The gas supply line 25 supplies a heat transfer gas (for example, He gas) from a heat transfer gas supply mechanism between the upper surface of the electrostatic chuck 20 and the back surface of the substrate W.

[0041] The plasma processing apparatus 1 further includes an upper electrode 30. The upper electrode 30 is provided above the mounting table 16. The upper electrode 30 is supported on the upper part of the chamber body 12 via a member 32. The material of the member 32 can be a material having insulating properties. The upper electrode 30 and the member 32 close the upper opening of the chamber body 12.

[0042] The upper electrode 30 may include a top plate 34 and a support 36. The lower surface of the top plate 34 is the lower surface on the side of the internal space 12c and defines the internal space 12c. The top plate 34 can be formed from a low-resistance conductor or semiconductor that generates little Joule heat. The top plate 34 has a plurality of gas discharge holes 34a penetrating through the top plate 34 in its plate thickness direction.

[0043] The support 36 detachably supports the top plate 34. The material of the support 36 can be a conductive material such as aluminum. A gas diffusion chamber 36a is provided inside the support 36. The support 36 has a plurality of gas holes 36b extending downward from the gas diffusion chamber 36a. The plurality of gas holes 36b communicate with the plurality of gas discharge holes 34a respectively. A gas inlet 36c is formed in the support 36. The gas inlet 36c is connected to the gas diffusion chamber 36a. A gas supply pipe 38 is connected to the gas inlet 36c.

[0044] A valve group 44, a flow controller group 42, and a gas source group 40 are connected to the gas supply pipe 38. 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 a plurality of gas sources. The valve group 44 includes a plurality of on-off valves. The flow controller group 42 includes a plurality of flow controllers. Each of the plurality of flow controllers in the flow controller group 42 is a mass flow controller or a pressure-controlled flow controller. Each of the plurality of gas sources in the gas source group 40 is connected to the gas supply pipe 38 via a corresponding on-off valve in the valve group 44 and a corresponding flow controller in the flow controller group 42.

[0045] A baffle plate 48 is provided between the cylindrical portion 28 and the side wall of the chamber body 12. The baffle plate 48 is configured, for example, by forming a corrosion-resistant film (such as a yttrium oxide film) on the surface of a base material formed of aluminum. A plurality of through holes are formed in the baffle plate 48. An exhaust port is provided below the baffle plate 48 and at the bottom of the chamber body 12. An exhaust device 50 is connected to the exhaust port via an exhaust pipe 52. The exhaust device 50 includes a vacuum pump such as a pressure regulating valve and a turbo molecular pump.

[0046] The plasma processing apparatus 1 includes a first high-frequency power source 62 and a second high-frequency power source 64. The first high-frequency power source 62 is a power source that generates first high-frequency power. The first high-frequency power has a frequency suitable for plasma generation. The frequency of the first high-frequency power is, for example, a frequency within the range of 27 to 100 [MHz]. The first high-frequency power source 62 is connected to the base 18 via a matching unit 66 and an electrode plate 21. The matching unit 66 has a circuit for matching the output impedance of the first high-frequency power source 62 and the impedance on the load side (the side of the base 18). Note that the first high-frequency power source 62 may be connected to the upper electrode 30 via the matching unit 66.

[0047] The second high-frequency power supply 64 is a power supply that generates 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 high-frequency power for bias to draw ions into the substrate W. The frequency of the second high-frequency power is, for example, a frequency within 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 unit 68 and an electrode plate 21. The matching unit 68 has a circuit for matching the output impedance of the second high-frequency power supply 64 and the impedance on the load side (the base 18 side).

[0048] Note that plasma may be generated using only the second high-frequency power without using the first high-frequency power, that is, using only a single high-frequency power. In this case, the frequency of the second high-frequency power may be a frequency greater than 13.56 [MHz], for example, 40 [MHz]. The plasma processing apparatus 1 may not include the first high-frequency power supply 62 and the matching unit 66.

[0049] In the plasma processing apparatus 1, gas is supplied from the gas supply unit to the internal space 12c, and plasma is generated. By supplying at least one of the first high-frequency power and the second high-frequency power, a high-frequency electric field is generated between the upper electrode 30 and the base 18 (lower electrode). Plasma is generated by the generated high-frequency electric field.

[0050] The plasma processing apparatus 1 may further include a control unit MC. The control unit MC can be a computer including a processor, a storage unit such as a memory, an input device, a display device, a signal input / output interface, and the like. The control unit MC controls each part of the plasma processing apparatus 1.

[0051] In the control unit MC, an operator can perform input operations of commands and the like for managing the plasma processing apparatus 1 using an input device. Also, in the control unit MC, the operating status of the plasma processing apparatus 1 can be visualized and displayed by a display device. Further, a control program and recipe data are stored in the storage unit. The control program is executed by a processor to execute various processes in the plasma processing apparatus 1. The processor executes the control program and controls each part of the plasma processing apparatus 1 according to the recipe data.

[0052] Referring to FIG. 2, the configuration of the region ER of the mounting table 16 shown in FIG. 1 will be described. In particular, the configurations of the conductive ring DR and the focus ring FR will be described in detail.

[0053] In the example shown in FIG. 2, the cover ring CR is composed of two dielectric members, an inner cover ring CRa and an outer cover ring CRb. Note that the cover ring CR may be composed of one dielectric member or three or more dielectric members.

[0054] The inner circumferential side (inner circumferential portion) of the focus ring FR is placed on the electrostatic chuck 20 which is the peripheral edge portion 31b of the mounting portion 31, and the outer circumferential side (outer circumferential portion) is arranged to cover the inner cover ring CRa. The outer circumferential portion of the focus ring FR may be placed on the inner cover ring CRa. The upper surface SFa of the inner cover ring CRa is formed lower than the upper surface of the peripheral edge portion 31b so that the inner circumferential portion of the focus ring FR is surely supported by the peripheral edge portion 31b, and a gap may be provided between the lower surface of the outer circumferential portion of the focus ring FR and the upper surface SFa of the inner cover ring CRa. That is, the outer circumferential portion of the focus ring FR may not be placed on the inner cover ring CRa. The thickness of the main body of the electrostatic chuck 20 is extremely small compared with the thickness of the inner cover ring CRa. For this reason, the focus ring FR is coupled as a high-frequency circuit to the first high-frequency power supply 62 and the second high-frequency power supply 64 via the electrostatic chuck 20. Also, as shown in FIG. 3, a power supply rod SP connected to the DC power supply DC and contacting 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 also be applied to the focus ring FR.

[0055] The conductive ring DR is placed on the outer cover ring CRb. Since the thickness of the outer cover ring CRb is large, the conductive ring DR is not coupled as a high-frequency circuit to the first high-frequency power supply 62 and the second high-frequency power supply 64 via the outer cover ring CRb.

[0056] The outer cover ring CRb includes an upper surface SFc on the inner peripheral side and an upper surface SFd on the outer peripheral side. Since the inner peripheral side of the outer cover ring CRb is close to the focus ring FR, it is more likely to wear out than the outer peripheral side. Therefore, in the example of FIG. 2, the conductive ring DR is arranged so as to cover only the portion that is likely to wear out (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 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 be arranged to cover the entire upper surface of the outer cover ring CRb. In the example of FIG. 2, the upper surface SFd on the outer peripheral side and the upper surface SFc on the inner peripheral side covered by the conductive ring DR are configured to be on the same plane, but they may also be configured 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.

[0057] As shown in FIG. 2, a gap AS is provided between the focus ring FR and the conductive ring DR. More specifically, 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. The inner peripheral lower surface ILSb of the conductive ring DR is located below the outer peripheral lower surface ILSa of the focus ring FR.

[0058] In the example shown in FIG. 2, the area of the second side surface SSb is configured to be smaller than the area of the upper surface SFb of the conductive ring DR. The upper surface SFb of the conductive ring DR is higher than the upper surface of the focus ring FR. In other words, the thickness of the inner periphery IPb of the conductive ring DR is thicker than the thickness of the outer periphery OPc of the focus ring FR.

[0059] The distance GA between the first side surface SSa and the second side surface SSb is the width of the gap AS. As will be 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 be greater than zero and smaller than the thickness SH of the focus ring FR.

[0060] The cover ring CR further includes a separation portion DT. The separation portion DT separates the first side surface SSa of the focus ring FR from the second side surface SSb of the conductive ring DR.

[0061] In the example shown in FIG. 2, by configuring the upper surface SFc on the inner circumferential side of the outer cover ring CRb to be lower than the upper surface SFa of the inner cover ring CRa, a step portion is provided between the inner cover ring CRa and the outer cover ring CRb to form the separation portion DT. Since the step portion abuts on the second side surface SSb of the conductive ring DR, the second side surface SSb of the conductive ring DR and the first side surface SSa of the focus ring FR do not contact each other. That is, by providing the separation portion DT, it is possible to prevent the first side surface SSa and the second side surface SSb from contacting each other and from ceasing to function as a capacitor.

[0062] In the mounting table 16 configured as described above, the conductive ring DR is disposed on the cover ring CR. Since the thickness of the cover ring CR is large compared to the thickness of the main body of the electrostatic chuck 20, the conductive ring DR is not coupled as a high-frequency circuit to the first high-frequency power source 62 and the second high-frequency power source 64 via the cover ring CR. Also, the first side surface SSa of the outer periphery OPc of the focus ring FR and the second side surface SSb of the inner periphery IPb of the conductive ring DR face each other and are spaced apart. Accordingly, the first side surface SSa and the second side surface SSb function as a capacitor. That is, the focus ring FR and the conductive ring DR are capacitively coupled at the first side surface SSa and the second side surface SSb. When high-frequency power is applied to the base 18, electrostatic induction occurs inside the conductive ring DR due to the positive or negative charges present on the first side surface SSa at the outer periphery OPc of the focus ring FR. For this reason, charges equal in amount and opposite to the charges that have gathered on the second side surface SSb of the conductive ring DR are attracted to the potential of the plasma and gather on the upper surface SFb of the conductive ring DR. Since the area of the upper surface SFb is larger than the area of the second side surface SSb, the amount of charge per unit area present on the upper surface SFb becomes smaller than the amount of charge per unit area present on the second side surface SSb. Therefore, the potential of the conductive ring DR becomes lower than the potential of the focus ring FR, and the acceleration of ions in the plasma toward the conductive ring DR is reduced. Thus, the conductive ring DR (i.e., the region outside the focus ring FR) is less likely to be sputtered.

[0063] The conductive ring DR is disposed so as to cover the easily consumable portion of the cover ring CR and is formed of a material having higher resistance to sputtering than the cover ring CR. Also, since the acceleration of ions toward the conductive ring DR is reduced, the conductive ring DR itself is less likely to be sputtered. Therefore, it is possible to suppress fluctuations in the area of the focus ring FR as a cathode due to the consumption of the cover ring CR around the outer periphery of the focus ring FR. For this reason, it is possible to suppress process fluctuations such as the occurrence of tilting at the end of the substrate.

[0064] Further, 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.

[0065] Furthermore, the conductive ring DR is disposed to face the first side surface SSa of the focus ring FR. Since an object (conductive ring DR) exists on 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. Therefore, the focus ring FR is less likely to be sputtered from the first side surface SSa, and thus the consumption of the focus ring FR can be suppressed.

[0066] In the example shown in FIG. 2, the substrate mounting portion 31a and the peripheral portion 31b on which the focus ring FR is mounted are constituted by the electrostatic chuck 20, 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 be provided independently. Also, as shown in FIG. 4, only the substrate mounting portion 31a may be used as the electrostatic chuck 20, and the peripheral portion 31b may be constituted by the base 18. Also, not only the inner peripheral side of the focus ring FR but also the entire focus ring may be mounted on the peripheral portion 31b. The peripheral portion 31b may be formed lower than the substrate mounting portion 31a and may be a stepped portion.

[0067] Also, in the example shown in FIG. 2, a separation portion DT is formed by configuring the upper surface SFc on the inner peripheral side of the outer cover ring CRb to be lower than the upper surface SFa of the inner cover ring CRa, but the present invention is not limited to this. As shown in FIG. 5, a concave groove may be provided in the cover ring CR on which the conductive ring DR is placed, and the lower surface ILSb on the inner periphery of the conductive ring DR may be provided in a convex shape facing downward. In this case, the lower surface ILSb on the inner periphery of the conductive ring DR is accommodated in the concave portion (groove) of the cover ring CR. By fitting the convex lower surface ILSb on the inner periphery into the concave groove, the position of the conductive ring DR in the cover ring CR can be stably maintained. In FIG. 5, although a groove is provided in the outer cover ring CRb as the separation portion DT, it 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. Further, in FIG. 5, 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 have 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.

[0068] Also, in the example shown in FIG. 2, the first side surface SSa of the focus ring FR and the second side surface SSb of the conductive ring DR are made to function as a capacitor by being separated from each other facing each other, but the present invention is not limited to this. As shown in FIG. 6, the lower surface of the outer peripheral portion of the focus ring FR and the upper surface of the inner peripheral portion of the conductive ring DR may be configured to be separated from each other facing each other. The conductive ring DR shown in FIG. 6 has a lower portion of the inner peripheral portion protruding toward the inner peripheral side. The upper surface of the protruding lower inner peripheral portion of the conductive ring DR and the lower surface of the focus ring FR are separated from each other facing each other. Also, 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 peripheral portion of the conductive ring DR, are separated from each other facing each other.

[0069] The upper surface SFc on the inner peripheral side of the outer cover ring CRb is lower than the upper surface SFa of the inner cover ring CRa, and a stepped portion serving as a separation portion DT is formed between the inner cover ring CRa and the outer cover ring CRb. Since the third side surface SSc, which is the side surface of the lower inner peripheral portion of the conductive ring DR, abuts against the stepped portion (the outer peripheral side surface of the inner cover ring CRa), the second side surface SSb, which is the side surface of the upper inner peripheral portion of the conductive ring DR, and the first side surface SSa of the focus ring FR do not contact each other. Also, the upper surface SFa of the inner cover ring CRa is formed at a position higher than the upper surface of the lower inner peripheral portion of the conductive ring DR. Therefore, since the lower surface of the focus ring FR abuts against the upper surface SFa of the inner cover ring CRa, the upper surface of the lower inner peripheral portion of the conductive ring DR and the lower surface of the focus ring do not contact each other.

[0070] In the example shown in FIG. 6, not only the first side surface SSa and the second side surface SSb, but also the lower surface of the outer peripheral portion of the focus ring FR and the upper surface of the lower inner peripheral portion of the conductive ring DR can function as a capacitor. Thereby, the capacitance between the focus ring FR and the conductive ring DR can be increased.

[0071] The distance GB between the lower surface of the outer peripheral portion of the focus ring FR and the upper surface of the lower inner peripheral portion of the conductive ring DR may be configured to be smaller than the distance GA between the first side surface SSa and the second side surface SSb. Since the distance GB is smaller than the distance GA, the capacitance between the lower surface of the outer peripheral portion of the focus ring FR and the upper surface of the lower inner peripheral portion of the conductive ring DR is larger than the capacitance between the first side surface SSa and the second side surface SSb. For this reason, even if the area of the first side surface SSa and the second side surface SSb fluctuates due to the consumption of the focus ring FR and the conductive ring DR, the fluctuation of the 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 suppress the void AS from being blocked by deposits and losing its function as a capacitor (or the capacitance fluctuating greatly).

[0072] The area of the upper surface of the lower inner peripheral portion of the conductive ring DR facing the lower surface of the outer peripheral portion of the focus ring FR may be configured to 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. Since the capacitance between the lower surface of the outer peripheral portion of the focus ring FR and the upper surface of the lower inner peripheral portion of the conductive ring DR increases, fluctuations in the capacitance between the focus ring FR and the conductive ring DR can be reduced.

[0073] As shown in the example of FIG. 6, an inclined portion may be formed between the inner peripheral side surface and the upper surface of the conductive ring DR. By providing the inclined portion, changes in the height of the upper surface of the focus ring FR and the upper surface of the conductive ring DR are alleviated, and discontinuities in the sheath formed above the conductive ring DR and the focus ring FR can be alleviated.

[0074] In the examples shown in FIGS. 2 to 6, the upper surface SFb of the conductive ring DR is configured to be higher than the upper surface of the focus ring FR, but it is not limited to this. 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.

[0075] In the example shown in FIG. 6, the lower surface of the outer peripheral portion of the focus ring FR and the upper surface of the inner peripheral portion of the conductive ring DR face each other and are spaced apart. As shown in FIG. 7, the upper surface of the outer peripheral portion of the focus ring FR and the lower surface of the inner peripheral portion of the conductive ring DR may be configured to face each other and be spaced apart.

[0076] The conductive ring DR shown in FIG. 7 has an upper portion of the inner peripheral portion protruding inward. The lower surface of the protruding upper inner peripheral portion of the conductive ring DR and the upper surface of the focus ring FR face each other and are spaced apart. Also, 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 peripheral portion of the conductive ring DR, face each other and are spaced apart.

[0077] The upper surface SFc on the inner circumferential side of the outer cover ring CRb is lower than the upper surface SFa of the inner cover ring CRa, and a stepped portion serving as a separation portion DT is formed between the inner cover ring CRa and the outer cover ring CRb. Since the second side surface SSb, which is the side surface of the lower inner circumferential portion of the conductive ring DR, abuts against the stepped portion (the outer circumferential side surface of the inner cover ring CRa), the second side surface SSb, which is the side surface of the upper inner circumferential portion of the conductive ring DR, does not contact the first side surface SSa of the focus ring FR. Also, the lower surface of the protruding upper inner circumferential portion of the conductive ring DR is formed at a position higher than the upper surface of the outer peripheral portion of the focus ring. Therefore, the lower surface of the upper inner circumferential portion of the conductive ring DR and the upper surface of the focus ring do not contact each other.

[0078] Similar to the example shown in FIG. 6, the distance GC between the upper surface of the outer peripheral portion of the focus ring FR and the lower surface of the upper inner circumferential portion of the conductive ring DR may be configured to be smaller than the distance GA between the first side surface SSa and the second side surface SSb. The area of the lower surface of the upper inner circumferential portion of the conductive ring DR facing the upper surface of the outer peripheral portion of the focus ring FR may be larger than the area of the inner circumferential side surface of the conductive ring DR facing the outer peripheral side surface of the focus ring FR.

[0079] In the example shown in FIG. 7, since the gap AS is covered by the upper inner circumferential portion of the conductive ring DR, it is possible to suppress the gap AS from being blocked by deposits and losing its function as a capacitor (or the capacitance fluctuating greatly).

[0080] In the examples shown in FIGS. 6 and 7, the lower surface (upper surface) of the outer peripheral portion of the focus ring FR and the upper surface (lower surface) of the inner circumferential portion of the conductive ring DR face each other and are separated, and the first side surface SSa of the focus ring FR and the second side surface SSb of the conductive ring DR face each other and are separated. However, only the lower surface (upper surface) of the outer peripheral portion of the focus ring FR and the upper surface (lower surface) of the inner circumferential portion of the conductive ring DR may face each other and be separated.

[0081] In the examples shown in FIGS. 2 to 7, the focus ring FR is arranged so as to cover the inner cover ring CRa on the outer peripheral side (outer peripheral portion) of the focus ring FR. However, the entire focus ring FR may be arranged on the electrostatic chuck 20 or the base 18. That is, not only the inner peripheral side (inner peripheral portion) of the focus ring FR but also the outer peripheral side (outer peripheral portion) may be placed on the electrostatic chuck 20 or the base 18 which is the peripheral edge portion 31b of the mounting portion 31.

[0082] FIG. 8 shows an example in which only the upper surface of the outer peripheral portion of the focus ring FR and the lower surface of the inner peripheral portion of the conductive ring DR are configured to face and be separated from each other. Also, the entire focus ring FR is placed on the electrostatic chuck 20.

[0083] The inner peripheral portion of the cover ring CR is placed on the outer peripheral portion of the focus ring FR. The conductive ring DR is placed on the cover ring CR. The inner peripheral portion of the conductive ring DR has a protruding portion that protrudes downward, and the lower surface of the protruding portion (lower surface of the inner peripheral portion) is separated from the upper surface of the outer peripheral portion of the focus ring FR while facing each other. Since the conductive ring DR is placed on the cover ring CR, the upper surface of the cover ring CR and the lower surface of the outer peripheral portion of the conductive ring DR are in contact. That is, the upper surface of the cover ring CR becomes the separation portion DT, and the lower surface of the protruding portion of the conductive ring DR and the upper surface of the outer peripheral portion of the focus ring FR do not contact each other. In the example shown in FIG. 8, a protruding portion that protrudes downward is formed on the inner peripheral portion of the conductive ring DR. However, if sufficient capacitance can be obtained between the lower surface of the inner peripheral portion of the conductive ring DR and the upper surface of the outer peripheral portion of the focus ring, the protruding portion may not be formed.

[0084] As described above, various exemplary embodiments have been described. However, the present invention is not limited to the above-described exemplary embodiments, and various omissions, substitutions, and changes may be made. Also, it is possible to form other exemplary embodiments by combining elements in different exemplary embodiments.

[0085] From the above description, it will be understood that the various exemplary embodiments of the present disclosure have been described herein for purposes of illustration and that various changes can be made without departing from the scope and spirit of the present disclosure. Accordingly, the various exemplary embodiments disclosed herein are not intended to be limiting, and the true scope and spirit are indicated by the appended claims.

Explanation of Reference Numerals

[0086] 1... Plasma processing apparatus, 10... Chamber, 12... Chamber body, 12c... Internal space, 12g... Gate valve, 12p... Passage, 15... Support portion, 16... Mounting table, 18... Base, 18f... Flow path, 20... Electrostatic chuck, 20p... DC power supply, 20s... Switch, 21... Electrode plate, 23a... Pipe, 23b... Pipe, 25... Gas supply line, 28... Cylindrical portion, 30... Upper electrode, 31... Mounting portion, 31a... Substrate mounting portion, 31b... Peripheral portion, 32... Member, 34... Top plate, 34a... Gas discharge hole, 36... Support, 36a... Gas diffusion chamber, 36b... Gas hole, 36c... Gas inlet, 38... Gas supply pipe, 40... Gas source group, 42... Flow controller group, 44... Valve group, 48... Baffle plate, 50... Exhaust device, 52... Exhaust pipe, 62... First high-frequency power supply, 64... Second high-frequency power supply, 66... Matching unit, 68... Matching unit, AS... Gap, CR... Covering, CRa... Inner covering, CRb... Outer covering, DC... DC power supply, DR... Conductive ring, DT... Spacing portion, ER... Region, FR... Focus ring, GA... Distance, ILSa... Outer peripheral lower surface, ILSb... Inner peripheral lower surface, IPb... Inner periphery, MC... Control unit, OPc... Outer periphery, OPd... Outer periphery, OPe... Outer periphery, SFa... Upper surface, SFb... Upper surface, SFc... Upper surface, SFd... Upper surface, SH... Thickness, SP... Feed bar, SSa... First side surface, SSb... Second side surface, W... Substrate.

Claims

1. A plasma processing chamber, a substrate support base including a base and an electrostatic chuck, disposed in the plasma processing chamber, at least one insulating ring disposed to surround the substrate support base, an inner conductive ring having an outer surface and disposed on the electrostatic chuck and the at least one insulating ring so as to surround a substrate on the electrostatic chuck, an outer conductive ring having an inner surface facing the outer surface of the inner conductive ring and disposed on the at least one insulating ring so as to surround the inner conductive ring without contacting the inner conductive ring, a high-frequency power source electrically coupled to the substrate support base, comprising: the at least one insulating ring includes a first insulating ring and a second insulating ring surrounding the first insulating ring, the inner conductive ring is disposed on the first insulating ring, the outer conductive ring is disposed on the second insulating ring, the upper surface of the first insulating ring has a first inner region and a first outer region, the inner conductive ring is disposed on the first inner region, the first outer region is exposed to a gap between the outer surface of the inner conductive ring and the inner surface of the outer conductive ring, a plasma processing apparatus.

2. the upper surface of the second insulating ring has a second inner region and a second outer region, the outer conductive ring is disposed on the second inner region, the second outer region is exposed to the plasma processing space of the plasma processing chamber, the plasma processing apparatus according to Claim 1.

3. The plasma processing apparatus according to Claim 2, wherein the position of the upper surface of the outer conductive ring is higher than the position of the upper surface of the inner conductive ring.

4. The plasma processing apparatus according to Claim 3, wherein the outer conductive ring has an inclined surface between the inner surface and the upper surface of the outer conductive ring.

5. A plasma processing chamber, a substrate support base including a base and an electrostatic chuck, disposed in the plasma processing chamber, at least one insulating ring disposed to surround the substrate support base, an inner conductive ring having an outer surface and disposed on the electrostatic chuck and the at least one insulating ring so as to surround a substrate on the electrostatic chuck, An outer conductive ring having an inner surface facing the outer surface of the inner conductive ring and disposed on the at least one insulating ring so as to surround the inner conductive ring without contacting the inner conductive ring; A high-frequency power source electrically coupled to the substrate support; comprising; The at least one insulating ring includes a first insulating ring and a second insulating ring surrounding the first insulating ring; The inner conductive ring is disposed on the first insulating ring; The outer conductive ring is disposed on the second insulating ring; The upper surface of the second insulating ring has an inner region and an outer region; The outer conductive ring is disposed on the inner region; The outer region is exposed to the plasma processing space of the plasma processing chamber; A plasma processing apparatus.

6. A plasma processing chamber; A substrate support disposed in the plasma processing chamber, including a base and an electrostatic chuck; At least one insulating ring disposed so as to surround the substrate support; An inner conductive ring having an outer surface and disposed on the electrostatic chuck and the at least one insulating ring so as to surround the substrate on the electrostatic chuck; An outer conductive ring having an inner surface facing the outer surface of the inner conductive ring and disposed on the at least one insulating ring so as to surround the inner conductive ring without contacting the inner conductive ring; A high-frequency power source electrically coupled to the substrate support; comprising; A plasma processing apparatus, wherein the position of the upper surface of the outer conductive ring is higher than the position of the upper surface of the inner conductive ring.

7. The plasma processing apparatus according to claim 6, wherein the outer conductive ring has an inclined surface between the inner surface and the upper surface of the outer conductive ring.

8. A plasma processing chamber; A substrate support disposed in the plasma processing chamber, including a base and an electrostatic chuck; At least one insulating ring disposed so as to surround the substrate support; An inner conductive ring having an outer surface and disposed on the electrostatic chuck and the at least one insulating ring so as to surround the substrate on the electrostatic chuck; An outer conductive ring having an inner surface facing the outer surface of the inner conductive ring and disposed on the at least one insulating ring so as to surround the inner conductive ring without contacting the inner conductive ring, A high-frequency power supply electrically coupled to the substrate support, Comprising, A plasma processing apparatus, wherein a position of a lower surface of the outer conductive ring is lower than a position of a lower surface of the inner conductive ring. **Claim 9**: A plasma processing chamber, A substrate support disposed in the plasma processing chamber, including a base and an electrostatic chuck, At least one insulating ring disposed so as to surround the substrate support, An inner conductive ring having an outer surface and disposed on the electrostatic chuck and the at least one insulating ring so as to surround a substrate on the electrostatic chuck, An outer conductive ring having an inner surface facing the outer surface of the inner conductive ring and disposed on the at least one insulating ring so as to surround the inner conductive ring without contacting the inner conductive ring, A high-frequency power supply electrically coupled to the substrate support, Comprising, A plasma processing apparatus, wherein the inner conductive ring and the outer conductive ring are capacitively coupled between the outer surface of the inner conductive ring and the inner surface of the outer conductive ring. **Claim 10**: The plasma processing apparatus according to any one of claims 1 to 9, wherein a distance between the outer surface of the inner conductive ring and the inner surface of the outer conductive ring is greater than zero and less than a thickness of the inner conductive ring. **Claim 11**: The plasma processing apparatus according to any one of claims 1 to 9, wherein the inner conductive ring is formed of silicon or silicon carbide. **Claim 12**: The plasma processing apparatus according to claim 11, wherein the outer conductive ring is formed of silicon or silicon carbide. **Claim 13**: The plasma processing apparatus according to claim 12, wherein the at least one insulating ring is formed of quartz. **Claim 14**: A substrate support assembly for use in a plasma processing apparatus, A substrate support, At least one insulating ring disposed so as to surround the substrate support, An inner conductive ring having an outer surface and disposed on at least one of the substrate support and the at least one insulating ring so as to surround a substrate on the substrate support, An outer conductive ring having an inner surface facing the outer surface of the inner conductive ring and disposed on the at least one insulating ring so as to surround the inner conductive ring without contacting the inner conductive ring, comprising, A substrate support base assembly in which the position of the upper surface of the outer conductive ring is higher than the position of the upper surface of the inner conductive ring.

15. The substrate support base assembly according to claim 14, wherein the outer conductive ring has an inclined surface between the inner surface and the upper surface of the outer conductive ring.

16. A substrate support base assembly for use in a plasma processing apparatus, a substrate support base, at least one insulating ring disposed so as to surround the substrate support base, an inner conductive ring having an outer surface and disposed on at least one of the substrate support base and the at least one insulating ring so as to surround a substrate on the substrate support base, an outer conductive ring having an inner surface facing the outer surface of the inner conductive ring and disposed on the at least one insulating ring so as to surround the inner conductive ring without contacting the inner conductive ring, comprising, A substrate support base assembly in which the inner conductive ring and the outer conductive ring are capacitively coupled between the outer surface of the inner conductive ring and the inner surface of the outer conductive ring.

17. The substrate support base assembly according to any one of claims 14 to 16, wherein the distance between the outer surface of the inner conductive ring and the inner surface of the outer conductive ring is greater than zero and less than the thickness of the inner conductive ring.

18. The plasma processing apparatus according to any one of claims 1 to 8, wherein the inner conductive ring and the outer conductive ring are capacitively coupled between the outer surface of the inner conductive ring and the inner surface of the outer conductive ring.

19. The plasma processing apparatus according to any one of claims 1 to 5, wherein the position of the upper surface of the outer conductive ring is higher than the position of the upper surface of the inner conductive ring.

20. The plasma processing apparatus according to any one of claims 1 to 5, wherein the position of the lower surface of the outer conductive ring is lower than the position of the lower surface of the inner conductive ring.

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