Plasma processing apparatus and substrate support unit assembly

Abstract

The invention relates to a plasma processing apparatus and a substrate supporting portion assembly. Techniques are provided for avoiding process variations caused by loss of a cap ring. According to one embodiment, a plasma processing apparatus includes a mounting table, a focus ring, a cap ring, a conductive ring, and a high-frequency power source. The focus ring is mounted on the mounting table and has conductivity. The conductive ring is placed on the cover ring. A first side surface positioned on the outer periphery of the focus ring and a second side surface positioned on the inner periphery of the conductive ring face each other and are separated from each other.

Description

[0001] (This application is a divisional application of an application with the application date of September 25, 2020, the application number of 2020110232231, and the invention name of “Plasma processing device”. TECHNICAL FIELD

[0002] An example embodiment of the present disclosure relates to a plasma processing device. BACKGROUND

[0003] For example, as disclosed in Patent Literature 1, a plasma processing device that performs substrate processing can have a structure that has a focus ring and a cover ring. By disposing the electrically conductive focus ring in a manner of surrounding the periphery of the semiconductor substrate, discontinuity of the bias potential at the end portion of the substrate is mitigated, and thus uniformity of plasma processing is improved. The cover ring of quartz is provided around the focus ring (also referred to as an edge ring). The outer peripheral side surface of the focus ring is covered by the cover ring.

[0004] Patent Literature 1: Japanese Patent Application Publication No. 2018-206913 SUMMARY

[0005] Problem to be solved by the invention

[0006] The cover ring of quartz or the like that covers the outer peripheral side surface of the focus ring is consumed over time due to sputtering of ions or the like of the plasma. The cover ring is particularly consumed on the side near the focus ring, and thus, as the cover ring is consumed, the outer peripheral side surface of the focus ring covered by the cover ring is exposed to the plasma. In such a case, the area of the focus ring as a cathode changes. That is, in a case where 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. In contrast, when the outer peripheral side surface of the focus ring is exposed due to consumption of the cover ring, the outer peripheral side surface of the focus ring also functions as a cathode. Thus, depending on before and after the consumption of the cover ring, process variation occurs in which the end portion of the substrate is tilted or the like. The present disclosure provides a technique for suppressing process variation caused by consumption of the cover ring.

[0007] Solution to the problem

[0008] In one example, a plasma processing apparatus is provided. The plasma processing apparatus includes a stage, a focus ring, a cover ring, a conductive ring, and a high-frequency power source. The stage has a substrate placement portion for placing a substrate and a peripheral portion surrounding the substrate placement portion. The focus ring is placed on the peripheral portion of the stage and is conductive. The cover ring surrounds the outer periphery of the stage and is composed of a dielectric. The conductive ring is placed on the cover ring. The high-frequency power source is combined with the stage. 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 separated. The cover ring has a separation portion that separates the focus ring and the conductive ring.

[0009] Effects of the invention

[0010] According to the present disclosure, a technique for suppressing process variation caused by loss of a cover ring can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 FIG. 1 is a diagram showing an example of a structure of a plasma processing apparatus according to one example embodiment.

[0012] Figure 2 FIG. 2 is a diagram showing an example of a structure of a conductive ring according to one example embodiment.

[0013] Figure 3 FIG. 3 is a diagram showing another example of a structure of a conductive ring according to one example embodiment.

[0014] Figure 4 FIG. 4 is a diagram showing an example of a structure of a conductive ring according to one example embodiment.

[0015] Figure 5 FIG. 5 is a diagram showing a variation of a structure of an inner peripheral lower surface of a conductive ring and a structure of a separation portion.

[0016] Figure 6 FIG. 6 is a diagram showing another example of a structure of a conductive ring according to one example embodiment.

[0017] Figure 7 FIG. 7 is a diagram showing another example of a structure of a conductive ring according to one example embodiment.

[0018] Figure 8 FIG. 8 is a diagram showing another example of a structure of a conductive ring according to one example embodiment. DETAILED DESCRIPTION

[0019] In one illustrative embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a stage, a focus ring, a cover ring, a conductive ring, and a high frequency power source. The stage has a substrate placement portion for placing a substrate and a peripheral portion surrounding the substrate placement portion. The focus ring is placed on the peripheral portion of the stage and is conductive. The cover ring surrounds an outer periphery of the stage and is composed of a dielectric. The conductive ring is placed on the cover ring. The high frequency power source is combined with the stage. A first surface on an outer peripheral portion of the focus ring and a second surface on an inner peripheral portion of the conductive ring face each other and are separated. The cover ring has a separation portion that separates the focus ring and the conductive ring. A first side surface on an outer periphery of the focus ring and a second side surface on an inner periphery of the conductive ring face each other and are separated. The focus ring functions as a cathode in plasma processing. The conductive ring in an electrically floating state is disposed so as to face the outer periphery of the focus ring.

[0020] In one illustrative embodiment, an inner peripheral portion of the focus ring is supported by the peripheral portion of the stage, and an outer peripheral portion of the focus ring covers an upper surface of an inner peripheral portion of the cover ring.

[0021] In one illustrative embodiment, the first surface is a side surface of the outer peripheral portion of the focus ring, and the second surface is a side surface of the inner peripheral portion of the conductive ring.

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

[0023] In one illustrative embodiment, the first surface is an upper surface of the outer peripheral portion of the focus ring, and the second surface is a lower surface of the inner peripheral portion of the conductive ring.

[0024] In one illustrative embodiment, a side surface of the outer peripheral portion of the focus ring and a side surface of the inner peripheral portion of the conductive ring face each other and are separated.

[0025] In one illustrative embodiment, an area of an upper surface of the inner peripheral portion of the conductive ring that faces a lower surface of the outer peripheral portion of the focus ring is larger than an area of a side surface of the inner peripheral portion of the conductive ring that faces a side surface of the outer peripheral portion of the focus ring.

[0026] In one illustrative embodiment, a gap between a lower surface of the outer peripheral portion of the focus ring and an upper surface of the inner peripheral portion of the conductive ring is narrower than a gap between a side surface of the outer peripheral portion of the focus ring and a side surface of the inner peripheral portion of the conductive ring.

[0027] In one illustrative embodiment, the focus ring and the conductive ring are capacitively coupled at the first surface and the second surface.

[0028] In one illustrative embodiment, a distance between the first surface and the second surface is larger than 0 and is smaller than a thickness of the focus ring.

[0029] In one illustrative embodiment, the inner peripheral portion lower surface of the conductive ring is positioned lower than the outer peripheral portion lower surface of the cover ring.

[0030] In one illustrative embodiment, the separation portion is a groove portion formed on the surface of the cover ring. The inner peripheral portion lower surface of the conductive ring is accommodated in the groove portion.

[0031] In one illustrative embodiment, the separation portion is a step portion configured to abut the inner peripheral portion side surface of the conductive ring and formed on the surface of the cover ring.

[0032] In one illustrative embodiment, the conductive ring is disposed such that the outer periphery of the conductive ring is positioned inside the outer periphery of the cover ring. The outer peripheral portion upper surface of the cover ring is exposed to the plasma processing space.

[0033] In one illustrative embodiment, the cover ring is composed of a plurality of dielectric members.

[0034] In one illustrative embodiment, the substrate placement portion and the peripheral portion are composed of an electrostatic chuck.

[0035] In one illustrative embodiment, the substrate placement portion is composed of an electrostatic chuck, and the peripheral portion is composed of a base pedestal of the placement pedestal.

[0036] In one illustrative embodiment, the conductive ring has a slope portion between the upper surface of the conductive ring and the inner peripheral portion side surface of the conductive ring.

[0037] In one illustrative embodiment, the material of the conductive ring is silicon or silicon carbide. The material of the cover ring is quartz.

[0038] Various illustrative embodiments will be described in detail below with reference to the drawings. In the drawings, like or corresponding elements are denoted by like reference numerals.

[0039] A plasma processing apparatus 1 of one illustrative embodiment is provided with a chamber 10. The chamber 10 provides an internal space 12c therein. The chamber 10 includes a chamber body 12. The chamber body 12 is substantially cylindrical in shape. The material of the chamber body 12 can be, for example, aluminum. A film having corrosion resistance is provided on the inner wall surface of the chamber body 12. The material of the film can be ceramic such as aluminum oxide or yttrium oxide.

[0040] A passage 12p is formed in the side wall of the chamber body 12. A 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.

[0041] 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 inner space 12c.

[0042] The support portion 15 extends upward from the bottom of the chamber body 12 along the side surface of the inner side of the substantially cylindrical cylindrical portion 28 in the inner space 12c. The support portion 15 has a substantially cylindrical shape. The material of the support portion 15 can be an insulating material such as ceramic. The support portion 15 has the stage 16 mounted thereon. The stage 16 is supported by the support portion 15. The stage 16 is configured to support the substrate W in the inner space 12c.

[0043] The stage 16 is provided on the support portion 15. The stage 16 has the placement portion 31, the base 18, and the electrode plate 21.

[0044] The placement portion 31 has a substrate placement portion 31a, which is a region for placing the substrate W, and a peripheral portion 31b, which is a region surrounding the substrate placement portion 31a. The focus ring FR having electrical conductivity is placed on the peripheral portion 31b. The conductive ring DR is placed on the cover ring CR in a concentric circular shape along the outer periphery OPc of the focus ring FR. The placement portion 31 can also be constituted by the electrostatic chuck 20.

[0045] The cover ring CR is provided on the cylindrical portion 28. The cover ring CR is an insulator and extends along the outer periphery of the stage 16. The cover ring CR is provided in a manner of surrounding the outer periphery of the placement portion 31 as viewed from above the placement portion 31 (as viewed from the upper electrode 30 side). The material of the cover ring CR is a material having insulating properties, and for example, can be ceramic such as quartz or alumina. The cover ring CR can be constituted by a plurality of dielectric members.

[0046] The conductive ring DR is disposed above the cover ring CR. The conductive ring DR is provided in a manner of surrounding the focus ring FR as viewed from above the placement portion 31. The conductive ring DR has a substantially ring-shaped plate shape and is formed of a material having electrical conductivity. The material of the conductive ring DR can be, for example, silicon (Si) or silicon carbide (SiC).

[0047] The electrode plate 21 is formed of a conductive material such as aluminum and has a substantially disc 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 disc shape. The base 18 is electrically connected to the electrode plate 21 and functions as a lower electrode.

[0048] An electrostatic chuck 20 is provided on the base 18 as a placement portion 31. The upper surface of the electrostatic chuck 20 places the substrate W thereon. The electrostatic chuck 20 has a main body and an electrode. The main body of the electrostatic chuck 20 is substantially 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 provided in the main body of the electrostatic chuck 20. The electrode of the electrostatic chuck 20 is connected to a direct current power source 20p via a switch 20s. When a voltage from the direct current power source 20p is applied to the electrode of the electrostatic chuck 20, electrostatic attraction is generated between the electrostatic chuck 20 and the substrate W. With this electrostatic attraction, the substrate W is held to the electrostatic chuck 20.

[0049] A focus ring FR is disposed 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 plasma processing performed on the substrate W. The focus ring FR is substantially ring-shaped plate-shaped and formed of a material having electrical conductivity. The material of the focus ring FR can be, for example, silicon (Si) or silicon carbide (SiC).

[0050] A flow path 18f is provided inside the base 18. A heat exchange medium (e.g., refrigerant) is supplied to the flow path 18f from a cooler 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 cooler unit via a pipe 23b. With 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.

[0051] A gas supply line 25 is provided in the plasma processing apparatus 1. The gas supply line 25 supplies a heat transfer gas (e.g., He gas) from a heat transfer gas supply mechanism to between the upper surface of the electrostatic chuck 20 and the back surface of the substrate W.

[0052] The plasma processing apparatus 1 further has an upper electrode 30. The upper electrode 30 is provided above the placement stage 16. The upper electrode 30 is supported to the upper portion of the chamber main body 12 by means of a member 32. The material of the member 32 can be a material having electrical insulation. The upper electrode 30 and the member 32 close the upper portion opening of the chamber main body 12.

[0053] The upper electrode 30 can include a top plate 34 and a support body 36. The lower surface of the top plate 34 is the lower surface on the inner space 12c side, which divides the inner space 12c. The top plate 34 can be formed of a conductor or a semiconductor having low resistance at which Joule heat is less generated. The top plate 34 has a plurality of gas ejection holes 34a that penetrate the top plate 34 in the plate thickness direction thereof.

[0054] The support body 36 supports the top plate 34 to be detachable. The support body 36 can be made of an electrically 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 respectively communicate with the plurality of gas ejection holes 34a. A gas introduction port 36c is formed in the support body 36. The gas introduction port 36c is connected to the gas diffusion chamber 36a. The gas introduction port 36c is connected to the gas supply pipe 38.

[0055] The gas supply pipe 38 is connected to a valve group 44, a flow rate controller group 42, and a gas source group 40. The gas source group 40, the valve group 44, and the flow rate controller group 42 constitute a gas supply section. The gas source group 40 includes a plurality of gas sources. The valve group 44 includes a plurality of on-off valves. The flow rate controller group 42 includes a plurality of flow rate controllers. The plurality of flow rate controllers of the flow rate controller group 42 are respectively mass flow controllers or pressure-controlled flow rate controllers. The plurality of gas sources of the gas source group 40 are respectively connected to the gas supply pipe 38 via the corresponding on-off valve of the valve group 44 and the corresponding flow rate controller of the flow rate controller group 42.

[0056] A baffle 48 is provided between the cylindrical portion 28 and the side wall of the chamber body 12. The baffle 48 is constituted, for example, by forming a film (a film of yttrium oxide or the like) having corrosion resistance on the surface of a base material made of aluminum. A plurality of through holes are formed in the baffle 48. An exhaust port is provided at a lower position than the baffle 48 and is the bottom of the chamber body 12. The exhaust port is connected to an exhaust device 50 via an exhaust pipe 52. The exhaust device 50 includes a pressure adjusting valve and a vacuum pump such as a turbo molecular pump.

[0057] The plasma processing device 1 is provided with 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 electric power. The first high-frequency electric power has a frequency suitable for generation of plasma. The frequency of the first high-frequency electric power is, for example, a frequency in the range of 27 [MHz] to 100 [MHz]. The first high-frequency power source 62 is connected to the base 18 via a matcher 66 and the electrode plate 21. The matcher 66 has a circuit for matching the output impedance of the first high-frequency power source 62 to the impedance on the load side (the base 18 side). In addition, the first high-frequency power source 62 can also be connected to the upper electrode 30 via the matcher 66.

[0058] The second high-frequency power supply 64 is a power source that generates a second high-frequency power. This second high-frequency power has a frequency lower than that of the first high-frequency power. When used in conjunction with the first high-frequency power, the second high-frequency power serves as a high-frequency power for biasing ions into the substrate W. The frequency of the second high-frequency power is, for example, 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 adapter 68 and an electrode plate 21. The matching adapter 68 has circuitry for matching the output impedance of the second high-frequency power supply 64 with the impedance of the load side (base 18 side).

[0059] Alternatively, a second high-frequency power source can be used instead of the first high-frequency power source, i.e., only a single high-frequency power source can be used to generate plasma. In this case, the frequency of the second high-frequency power source can be a frequency greater than 13.56 [MHz], for example, 40 [MHz]. The plasma processing apparatus 1 may also be without the first high-frequency power source 62 and the matching device 66.

[0060] In the plasma processing apparatus 1, gas is supplied from the gas supply unit into the internal space 12c to generate plasma. A high-frequency electric field is generated between the upper electrode 30 and the base 18 (lower electrode) by supplying at least one of a first high-frequency power and a second high-frequency power. Plasma is generated using the generated high-frequency electric field.

[0061] The plasma processing apparatus 1 may also include a control unit MC. The control unit MC may be a computer equipped with a processor, memory and other storage units, input devices, display devices, signal input / output interfaces, etc. The control unit MC controls all parts of the plasma processing apparatus 1.

[0062] In the control unit (MC), the operator can use the input device to input commands and manage the plasma processing apparatus 1. Furthermore, the operating status of the plasma processing apparatus 1 can be visually displayed using a display device in the control unit (MC). Control programs and process data are stored in the storage unit. The processor executes the control program to perform 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 process data.

[0063] Reference Figure 2 ,illustrate Figure 1 The structure of region ER of stage 16 is shown. The structures of the conductive ring DR and the focusing ring FR are explained in detail in particular.

[0064] exist Figure 2 In the example shown, the cover ring CR is composed of two dielectric components: an inner cover ring CRa and an outer cover ring CRb. Alternatively, the cover ring CR can be composed of one dielectric component, or it can be composed of three or more dielectric components.

[0065] The inner peripheral side (inner peripheral portion) of the focusing ring FR is mounted on the peripheral portion 31b of the mounting portion 31, i.e., the electrostatic chuck 20, and the outer peripheral side (outer peripheral portion) is arranged to cover the inner cover ring CRa. The outer peripheral portion of the focusing ring FR may also be mounted on the inner cover ring CRa. 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 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 mounted 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. Furthermore, as... Figure 3 As shown, it can also be configured such that a power supply rod SP, which is connected to a DC power supply and contacts the lower surface of the focusing ring FR, is arranged in the through hole of the inner cover ring CRa, so that a DC voltage can be applied to the focusing ring FR.

[0066] The conductive ring DR is mounted on the outer cover ring CRb. Because the outer cover ring CRb is thicker, the conductive ring DR will not couple with the first high-frequency power supply 62 and the second high-frequency power supply 64 as a high-frequency circuit through the outer cover ring CRb.

[0067] The outer cover ring CRb has an inner circumferential upper surface SFc and an outer circumferential upper surface SFd. The inner circumferential side of the outer cover ring CRb is more prone to wear than the outer circumferential side due to its proximity to the focusing ring FR. Therefore, in Figure 2 In the example, the conductive ring DR is configured to cover only the easily worn area (the upper surface SFc of the inner circumference of the outer cover ring CRb). That is, the outer circumference OPd of the conductive ring DR is configured to be located inside the outer circumference OPe of the cover ring CR, and the upper surface of the outer circumference of the cover ring CR is exposed to the plasma processing space (internal space 12c). However, it is also possible for the conductive ring DR to be configured to cover the entire upper surface of the outer cover ring CRb. Furthermore, in Figure 2 In the example, the upper surface SFd on the outer periphery is configured to be on the same plane as the upper surface SFc on the inner periphery covered by the conductive ring DR, but they can 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 can be higher than the upper surface SFb of the conductive ring DR, or they can be at the same height.

[0068] like Figure 2A gap AS is provided between the focus ring FR and the conductive ring DR. More specifically, a first side surface SSa located at an outer peripheral edge OPc of the focus ring FR and a second side surface SSb located at an inner peripheral edge IPb of the conductive ring DR face each other and are separated from each other. An inner peripheral lower surface ILSb of the conductive ring DR is located at a position lower than an outer peripheral lower surface ILSa of the focus ring FR.

[0069] In Figure 2 In the illustrated example, 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 peripheral edge IPb of the conductive ring DR is thicker than the thickness of the outer peripheral edge OPc of the focus ring FR.

[0070] 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. Thus, it is desirable that the distance GA be larger than 0 and smaller than the thickness SH of the focus ring FR.

[0071] The cover ring CR further has a separation portion DT. The separation portion DT separates the first side surface SSa of the focus ring FR and the second side surface SSb of the conductive ring DR.

[0072] In Figure 2 In the illustrated example, 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, and a step portion is provided between the inner cover ring CRa and the outer cover ring CRb to thereby constitute the separation portion DT. Since the step portion and the second side surface SSb of the conductive ring DR are in abutment, the second side surface SSb of the conductive ring DR does not come into contact with the first side surface SSa of the focus ring FR. 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 coming into contact with each other and functioning as a capacitor.

[0073] In the stage 16 of the above-described structure, the conductive ring DR is disposed above the cover ring CR. Since the thickness of the cover ring CR is thicker than the thickness of the main body of the electrostatic chuck 20, the conductive ring DR is not coupled with the first high-frequency power source 62 and the second high-frequency power source as the high-frequency circuit 64 through the cover ring CR. Further, 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 separated from each other. Thus, 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. The first side surface SSa is located at the outer periphery OPc of the focus ring FR, and when high-frequency power is applied to the base 18, electrostatic induction is generated in the inside of the conductive ring DR by using positive or negative charges present at the first side surface SSa. Thus, charges equal to and opposite to the charges gathered at the second side surface SSb of the conductive ring DR are attracted by the potential of the plasma and gathered at 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 charges per unit area present at the upper surface SFb is smaller than the amount of charges per unit area present at the second side surface SSb. Thus, the potential of the conductive ring DR is lower than the potential of the focus ring FR, and the acceleration of ions in the plasma toward the conductive ring DR is reduced. Therefore, the conductive ring DR (i.e., the region outside the focus ring FR) is difficult to be sputtered.

[0074] The conductive ring DR is disposed so as to cover the position of the cover ring CR which is easily lost, and is formed of a material having higher resistance to sputtering than the cover ring CR. Further, since the acceleration of ions toward the conductive ring DR is reduced, the conductive ring DR itself is also difficult to be sputtered. Thus, it is possible to suppress the change in the area of the focus ring FR as a cathode due to the loss of the cover ring CR around the outer periphery of the focus ring FR. Therefore, it is possible to suppress the process variation such as the occurrence of tilt at the end portion of the substrate.

[0075] Further, by adjusting the area of the upper surface SFb of the conductive ring DR, it is possible to adjust the potential of the upper surface SFb of the conductive ring DR.

[0076] Moreover, the conductive ring DR is disposed so as to face the first side surface SSa of the focus ring FR. Since there is an object (the conductive ring DR) on the side of the first side surface SSa of the focus ring FR, ions toward the first side surface SSa are shielded by the conductive ring DR. Therefore, the focus ring FR is difficult to be sputtered from the first side surface SSa, and thus it is possible to suppress the loss of the focus ring FR.

[0077] In addition, in the conductive ring DR, the second side surface SSb of the inner periphery IPb is formed so as to be inclined toward the upper surface SFb of the conductive ring DR. Thus, the second side surface SSb of the inner periphery IPb is inclined toward the upper surface SFb of the conductive ring DR. Therefore, the conductive ring DR is difficult to be sputtered from the second side surface SSb of the inner periphery IPb, and thus it is possible to suppress the loss of the conductive ring DR. Figure 2In the illustrated example, the electrostatic chuck 20 constitutes the substrate placement portion 31a and the peripheral portion 31b of the placement focus ring FR, but is not limited thereto. The electrostatic chuck of the substrate placement portion 31a and the electrostatic chuck of the peripheral portion 31b can be provided independently of each other. Further, as illustrated in Figure 4 In the illustrated example, the electrostatic chuck 20 constitutes the substrate placement portion 31a and the peripheral portion 31b of the placement focus ring FR, but is not limited thereto. The electrostatic chuck of the substrate placement portion 31a and the electrostatic chuck of the peripheral portion 31b can be provided independently of each other. Further, as illustrated in

[0078] Further, in Figure 2 In the illustrated example, the upper surface SFc of the outer side cover ring CRb is formed lower than the upper surface SFa of the inner side cover ring CRa, thereby constituting the separation portion DT, but is not limited thereto. As illustrated in Figure 5 In the illustrated example, the upper surface SFc of the outer side cover ring CRb is formed lower than the upper surface SFa of the inner side cover ring CRa, thereby constituting the separation portion DT, but is not limited thereto. As illustrated in Figure 5 In the illustrated example, the outer side cover ring CRb is provided with a groove as the separation portion DT, but a groove can be provided on the inner side cover ring CRa side. In this case, the inner peripheral side of the conductive ring DR is placed on the inner side cover ring CRa, and the outer peripheral side of the conductive ring DR is placed on the outer side cover ring CRb. Further, in Figure 5 In the illustrated example, 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 formed to the same height, but can be formed to different heights. For example, the upper surface SFc of the cover ring CR on which the conductive ring DR is placed can be formed higher than the upper surface SFa of the cover ring CR on which the focus ring FR is placed.

[0079] Further, in Figure 2 In the illustrated example, 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 separated from each other, thereby functioning as a capacitor, but is not limited thereto. As illustrated in Figure 6 In the illustrated example, 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 separated from each other, thereby functioning as a capacitor, but is not limited thereto. As illustrated in Figure 6 The inner peripheral portion of the conductive ring DR is illustrated as protruding downward. The upper surface of the protruding inner peripheral portion of the conductive ring DR and the lower surface of the focus ring FR are opposed to and separated from each other. Further, the first side surface SSa of the focus ring FR and the side surface of the upper inner peripheral portion of the conductive ring DR, i.e., the second side surface SSb, are opposed to and separated from each other.

[0080] The upper surface SFc of the inner periphery side of the outer cover ring CRb is lower than the upper surface SFa of the inner cover ring CRa, and a step portion that becomes the separation portion DT is formed between the inner cover ring CRa and the outer cover ring CRb. The side surface of the lower inner periphery portion of the conductive ring DR, that is, the third side surface SSc, abuts against the step portion (the outer periphery side surface of the inner cover ring CRa), and thus the side surface of the upper inner periphery portion of the conductive ring DR, that is, the second side surface SSb, does not come into contact with the first side surface SSa of the focus ring FR. In addition, the upper surface SFa of the inner cover ring CRa is formed at a position higher than the upper surface of the lower inner periphery portion of the conductive ring DR. Thus, 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 periphery portion of the conductive ring DR does not come into contact with the lower surface of the focus ring.

[0081] In Figure 6 In the example shown, not only the first side surface SSa and the second side surface SSb, but also the outer periphery lower surface of the focus ring FR and the upper surface of the lower inner periphery portion of the conductive ring DR can function as a capacitor. Thus, the capacitance between the focus ring FR and the conductive ring DR can be increased.

[0082] The distance GB between the outer periphery lower surface of the focus ring FR and the upper surface of the lower inner periphery portion of the conductive ring DR can also be made 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 outer periphery lower surface of the focus ring FR and the upper surface of the lower inner periphery portion of the conductive ring DR is larger than the capacitance between the first side surface SSa and the second side surface SSb. Thus, even if the areas of the first side surface SSa and the second side surface SSb change due to wear of the focus ring FR and the conductive ring DR, the change in the capacitance between the focus ring FR and the conductive ring DR can be reduced. Also, since the distance GA between the first side surface SSa and the second side surface SSb can be increased, the situation in which the gap AS is clogged with the deposits and does not function as a capacitor (or the capacitance changes greatly) can be suppressed.

[0083] The area of the upper surface of the lower inner periphery portion of the conductive ring DR that opposes the outer periphery lower surface of the focus ring FR can also be made larger than the area of the inner periphery side surface of the conductive ring DR that opposes the outer periphery side surface of the focus ring FR. Since the capacitance between the outer periphery lower surface of the focus ring FR and the upper surface of the lower inner periphery portion of the conductive ring DR is increased, the change in the capacitance between the focus ring FR and the conductive ring DR can be reduced.

[0084] As Figure 6As shown in the example, an inclined portion can also be formed between the inner circumferential side surface and the upper surface of the conductive ring DR. By providing the inclined portion, the height difference between the upper surface of the focusing ring FR and the upper surface of the conductive ring DR can be mitigated, thereby mitigating the discontinuity of the sheath formed above the conductive ring DR and the focusing ring FR.

[0085] exist Figures 2 to 6 In the example shown, the upper surface SFb of the conductive ring DR is higher than the upper surface of the focusing ring FR, but this is not the only possibility. The upper surface SFb of the conductive ring DR may also be configured to have the same height as the upper surface of the focusing ring FR, or it may be configured to be lower than the upper surface of the focusing ring FR.

[0086] exist Figure 6 In the example shown, the lower outer surface of the focusing ring FR and the upper inner outer surface of the conductive ring DR are opposite to each other and separated. Additionally, as... Figure 7 As shown, it can also be configured such that the upper surface of the outer periphery of the focusing ring FR and the lower surface of the inner periphery of the conductive ring DR are opposite to each other and separated.

[0087] Figure 7 The upper part of the inner circumference of the conductive ring DR protrudes inward. The lower surface of the protruding upper inner circumference of the conductive ring DR and the upper surface of the focusing ring FR are opposite to each other and separated. In addition, the first side surface SSa of the focusing ring FR and the second side surface SSb of the lower inner circumference of the conductive ring DR are opposite to each other and separated.

[0088] The upper surface SFc of the inner circumference of the outer cover ring CRb is lower than the upper surface SFa of the inner cover ring CRa, forming a stepped portion that becomes the separation section DT between the inner cover ring CRa and the outer cover ring CRb. The side surface SSb of the lower inner circumference of the conductive ring DR abuts against the stepped portion (the outer circumferential side surface of the inner cover ring CRa). Therefore, the side surface SSb of the upper inner circumference of the conductive ring DR does not contact the first side surface SSa of the focusing ring FR. Furthermore, the lower surface of the protruding upper inner circumference of the conductive ring DR is formed at a position higher than the upper surface of the outer circumference of the focusing ring. Therefore, the lower surface of the upper inner circumference of the conductive ring DR does not contact the upper surface of the focusing ring.

[0089] and Figure 6 Similarly, in the example shown, the distance GC between the upper surface of the outer periphery of the focusing ring FR and the lower surface of the lower inner periphery of the conductive ring DR can be smaller than the distance GA between the first side surface SSa and the second side surface SSb. Alternatively, the area of ​​the lower surface of the upper inner periphery of the conductive ring DR opposite the upper surface of the outer periphery of the focusing ring FR can be larger than the area of ​​the inner periphery side surface of the conductive ring DR opposite the outer periphery side surface of the focusing ring FR.

[0090] existFigure 7 In the illustrated example, the gap AS is covered by the upper inner periphery of the conductive ring DR, and thus, it is possible to inhibit the gap AS from being clogged by the deposited material and not functioning as a capacitor (or the capacitance greatly changing).

[0091] In Figure 6 and Figure 7 In the illustrated example, the outer periphery lower surface (upper surface) of the focus ring FR and the inner periphery upper surface (lower surface) 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, it is also possible that only the outer periphery lower surface (upper surface) of the focus ring FR and the inner periphery upper surface (lower surface) of the conductive ring DR face each other and are separated.

[0092] In Figures 2 to 7 In the illustrated example, the focus ring FR is disposed in a manner that the outer periphery (outer periphery portion) of the focus ring FR covers the inner side cover ring CRa. However, it is also possible to dispose the entire focus ring FR on the electrostatic chuck 20 or the base 18. That is, not only the inner periphery (inner periphery portion) of the focus ring FR, but also the outer periphery (outer periphery portion) can be placed on the electrostatic chuck 20 or the base 18 as the peripheral portion 31b of the placement portion 31.

[0093] In Figure 8 An example in which the focus ring FR is configured such that only the outer periphery upper surface of the focus ring FR and the inner periphery lower surface of the conductive ring DR face each other and are separated is shown. In addition, the entire focus ring FR is placed on the electrostatic chuck 20.

[0094] 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 protruding portion protruding downward, and the protruding portion lower surface (inner periphery lower surface) and the focus ring FR outer periphery upper surface face each other and are separated. The conductive ring DR is placed on the cover ring CR, and thus, the cover ring CR upper surface and the conductive ring DR outer periphery lower surface abut. That is, the upper surface of the cover ring CR becomes the separation portion DT, and the protruding portion lower surface of the conductive ring DR does not contact the outer periphery upper surface of the focus ring FR. In addition, in the example shown in Figure 8 In the illustrated example, the protruding portion protruding downward is formed in the inner periphery of the conductive ring DR, but as long as sufficient capacitance can be obtained between the inner periphery lower surface of the conductive ring DR and the outer periphery upper surface of the focus ring, the protruding portion can not be formed.

[0095] The above describes various example embodiments, but is not limited to the above-described example embodiments, and various omissions, substitutions, and changes can be made. In addition, elements of different example embodiments can be combined to form other example embodiments.

[0096] In accordance with the above description, various exemplary embodiments of the present disclosure are described in the present specification for the purpose of illustration, and it should be understood that various changes can be made without departing from the scope and spirit of the present disclosure. Thus, the various exemplary embodiments disclosed in the present specification are not intended to be limiting, and the true scope and spirit of the present disclosure are represented by the claims.

Claims

1. A plasma processing apparatus, comprising: Plasma processing chamber; A substrate support portion is disposed in the plasma processing chamber, the substrate support portion including a base and an electrostatic chuck disposed on the base; At least one insulating ring is arranged to surround the substrate support portion; An inner conductive ring is arranged on the electrostatic chuck and the at least one insulating ring in such a way that it surrounds the substrate on the electrostatic chuck, and the inner conductive ring has an outer side surface. An outer conductive ring, arranged on the at least one insulating ring in a manner that surrounds the inner conductive ring without contacting it, the outer conductive ring having an inner side facing the outer side of the inner conductive ring; and A radio frequency power supply, which is electrically coupled to the substrate support portion.

2. The plasma processing apparatus according to claim 1, wherein, 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 arranged on the first insulating ring, and The outer conductive ring is arranged on the second insulating ring.

3. The plasma processing apparatus according to claim 2, wherein, The upper surface of the first insulating ring has a first inner region and a first outer region. The inner conductive ring is arranged on the first inner region, and The first outer region is exposed in the space between the outer side surface of the inner conductive ring and the inner side surface of the outer conductive ring.

4. The plasma processing apparatus according to claim 3, wherein, The upper surface of the second insulating ring has a second inner region and a second outer region. The outer conductive ring is arranged on the second inner region, and The second outer region is exposed to the plasma processing space of the plasma processing chamber.

5. The plasma processing apparatus according to claim 4, wherein, The upper surface of the outer conductive ring is higher than the upper surface of the inner conductive ring.

6. The plasma processing apparatus according to claim 5, wherein, The outer conductive ring has an inclined surface between its inner side surface and its upper surface.

7. The plasma processing apparatus according to claim 2, wherein, The upper surface of the second insulating ring has a second inner region and a second outer region. The outer conductive ring is arranged on the second inner region, and The second outer region is exposed to the plasma processing space of the plasma processing chamber.

8. The plasma processing apparatus according to claim 1, wherein, The upper surface of the outer conductive ring is higher than the upper surface of the inner conductive ring.

9. The plasma processing apparatus according to claim 8, wherein, The outer conductive ring has an inclined surface between its inner side surface and its upper surface.

10. The plasma processing apparatus according to claim 1, wherein, The inner conductive ring and the outer conductive ring are capacitively coupled between the outer side surface of the inner conductive ring and the inner side surface of the outer conductive ring.

11. The plasma processing apparatus according to claim 1, wherein, The distance between the outer side surface of the inner conductive ring and the inner side surface of the outer conductive ring is greater than 0 and smaller than the thickness of the inner conductive ring.

12. The plasma processing apparatus according to claim 1, wherein, The lower surface of the outer conductive ring is lower than the lower surface of the inner conductive ring.

13. The plasma processing apparatus according to claim 1, wherein, The inner conductive ring is formed of silicon or silicon carbide.

14. The plasma processing apparatus according to claim 13, wherein, The outer conductive ring is formed of silicon or silicon carbide.

15. The plasma processing apparatus according to claim 14, wherein, The at least one insulating ring is formed of quartz.

16. A substrate support assembly for use in a plasma processing apparatus, the substrate support assembly comprising: Substrate support portion; At least one insulating ring is arranged to surround the substrate support portion; An inner conductive ring, arranged to surround the substrate on the substrate support and at least one of the at least one insulating ring, the inner conductive ring having an outer side surface; and An outer conductive ring is arranged on the at least one insulating ring in a manner that surrounds the inner conductive ring without contacting it, the outer conductive ring having an inner side facing the outer side of the inner conductive ring.

17. The substrate support assembly according to claim 16, wherein, The upper surface of the outer conductive ring is higher than the upper surface of the inner conductive ring.

18. The substrate support assembly according to claim 17, wherein, The outer conductive ring has an inclined surface between its inner side surface and its upper surface.

19. The substrate support assembly according to claim 16, wherein, The inner conductive ring and the outer conductive ring are capacitively coupled between the outer side surface of the inner conductive ring and the inner side surface of the outer conductive ring.

20. The substrate support assembly according to claim 16, wherein, The distance between the outer side surface of the inner conductive ring and the inner side surface of the outer conductive ring is greater than 0 and smaller than the thickness of the inner conductive ring.

Images