Plasma processing device

Abstract

The disclosed plasma processing apparatus includes a chamber, a substrate support part, an excitation electrode, an emission unit, and a resonator. The substrate support part is provided in a processing space in the chamber. The excitation electrode is provided above the substrate support part. The emission unit emits electromagnetic waves into a plasma generation space below the excitation electrode. The resonator is provided on the excitation electrode and is electromagnetically coupled to the emission unit. A conductor portion that defines the waveguide of the resonator is formed from a first conductor in a first portion including a position 1 / 4 of a wavelength in the guide of the electromagnetic wave in the resonator from one end of the waveguide, and is formed from a second conductor in a second portion other than the first portion. The thermal conductivity of the first conductor is lower than the thermal conductivity of the second conductor.

Description

Plasma processing equipment

[0001] An exemplary embodiment of the present disclosure relates to a plasma processing apparatus.

[0002] Plasma processing apparatuses are used in substrate processing. One type of plasma processing apparatus is known, which excites gases using high-frequency waves, such as VHF waves or UHF waves. Patent Document 1 below discloses such a plasma processing apparatus. The plasma processing apparatus of Patent Document 1 includes a processing vessel, a stage, an upper electrode, an introduction section, and a waveguide section. The stage is provided within the processing vessel. The upper electrode is provided above the stage via a space within the processing vessel. The introduction section is an introduction section for high-frequency waves. The introduction section is provided at a lateral end of the space and extends circumferentially around a central axis of the processing vessel. The waveguide section is configured to supply high-frequency waves to the introduction section. The waveguide section includes a resonator providing a waveguide. The waveguide of the resonator extends circumferentially around the central axis, extends in the direction of the central axis, and is connected to the introduction section.

[0003] Japanese Patent Application Laid-Open No. 2020-92031

[0004] The present disclosure provides a technique for suppressing heat conduction from an excitation electrode of a plasma processing apparatus via a resonator, and suppressing current loss.

[0005] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, an excitation electrode, an emission portion, and a resonator. The chamber provides a processing space therein. The substrate support is provided within the processing space. The excitation electrode is provided above the substrate support. The emission portion is configured to emit electromagnetic waves into the plasma generation space below the excitation electrode. The resonator is provided on the excitation electrode and is electromagnetically coupled to the emission portion. The resonator includes a conductor portion defining a waveguide thereof. The conductor portion is formed from a first conductor in a first portion that includes a position from one end of the waveguide to a position one-quarter of the guide wavelength of the electromagnetic wave in the resonator, and is formed from a second conductor in a second portion other than the first portion. The thermal conductivity of the first conductor is lower than that of the second conductor.

[0006] According to one exemplary embodiment, it is possible to suppress heat conduction from an excitation electrode of a plasma processing apparatus through a resonator, and to suppress current loss.

[0007] 6A and 6B are diagrams illustrating a plasma processing apparatus according to one exemplary embodiment. A cross-sectional view taken along line II-II in FIG. 1. A cross-sectional view taken along line III-III in FIG. 1. A cross-sectional view taken along line IV-IV in FIG. 1. A cross-sectional view taken along line V-V in FIG. 1. A cross-sectional view taken along line VII-VII in FIG. 6. A cross-sectional view taken along line VIII-VIII in FIG. 6. A cross-sectional view taken along line IX-IX in FIG. 6. A cross-sectional view taken along line XX in FIG. 6. A cross-sectional view taken along line XX in FIG. 6. A cross-sectional view according to yet another exemplary embodiment.

[0008] Various exemplary embodiments will be described in detail below with reference to the drawings, in which the same or equivalent parts are designated by the same reference numerals.

[0009] FIG. 1 is a diagram showing a plasma processing apparatus according to an exemplary embodiment. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 1. FIG. 5 is a cross-sectional view taken along line V-V in FIG. 1. The plasma processing apparatus 1 shown in FIGS. 1 to 5 includes a chamber 10, a substrate support 12, an excitation electrode 14, an emission section 16, and a resonator 30. The plasma processing apparatus 1 may further include a control section 2.

[0010] The chamber 10 provides a processing space 10s therein. In the plasma processing apparatus 1, the substrate W is processed in the processing space 10s. The chamber 10 is made of a metal such as aluminum and is grounded. The chamber 10 has a sidewall 10a and is open at its upper end. The chamber 10 and the sidewall 10a may have a substantially cylindrical shape. The processing space 10s is provided inside the sidewall 10a. The central axis of each of the chamber 10, the sidewall 10a, and the processing space 10s is the axis AX. The chamber 10 may have a corrosion-resistant film on its surface. The corrosion-resistant film may be a ceramic film containing yttrium oxide, yttrium oxide fluoride, yttrium fluoride, yttrium oxide, yttrium fluoride, or the like.

[0011] The bottom of the chamber 10 is provided with an exhaust port 10e, which is connected to an exhaust system that may include a vacuum pump such as a dry pump and / or a turbomolecular pump, and an automatic pressure control valve.

[0012] The substrate support 12 is provided in the processing space 10s. The substrate support 12 is configured to support the substrate W placed on its upper surface in a substantially horizontal position. The substrate support 12 has a substantially disk shape. The central axis of the substrate support 12 is an axis AX.

[0013] The excitation electrode 14 is provided above the substrate support 12 via the processing space 10s. The excitation electrode 14 is made of a conductive material such as metal (e.g., aluminum) and has a substantially disk shape. The central axis of the excitation electrode 14 is an axis AX.

[0014] The emitter 16 is provided to emit electromagnetic waves from there into a plasma generation space. In the plasma processing apparatus 1, the plasma generation space is within the processing space 10s and the space below the excitation electrode 14. The electromagnetic waves emitted from the emitter 16 into the plasma generation space may be high-frequency waves such as VHF waves or UHF waves. The emitter 16 is formed from a dielectric material such as quartz, aluminum nitride, or aluminum oxide. The emitter 16 extends circumferentially around the axis AX. The emitter 16 may have a ring shape. The emitter 16 may extend to surround the plasma generation space or a shower plate 141 (described later). In the plasma processing apparatus 1, the gas in the chamber 10 is excited by the electromagnetic waves emitted from the emitter 16 into the plasma generation space. As a result, plasma is generated in the plasma generation space.

[0015] In one embodiment, the excitation electrode 14 may include a shower plate 141 and an upper electrode 142. The shower plate 141 is provided above the plasma generation space. The shower plate 141, together with the emission section 16, closes the opening at the upper end of the chamber 10. The shower plate 141 provides a plurality of gas holes 14h. The plurality of gas holes 14h extend in the thickness direction (vertical direction) of the shower plate 141 and penetrate the shower plate 141.

[0016] The upper electrode 142 is provided on the shower plate 141. The upper electrode 142 forms a gas diffusion chamber 14d between the shower plate 141 and the upper electrode 142. A gas supply unit 20 is connected to the gas diffusion chamber 14d. Gas from the gas supply unit 20 is discharged through the gas diffusion chamber 14d and a plurality of gas holes 14h into the plasma generation space (processing space 10s).

[0017] In one embodiment, the excitation electrode 14 may have a built-in heating mechanism 143. The heating mechanism 143 may be provided in the upper electrode 142. The heating mechanism 143 may be an electric heater, for example, a resistance heating element. In this case, the heating mechanism 143 is connected to the heater power supply 22. The heating mechanism 143 generates heat by power supplied from the heater power supply 22. The plasma processing apparatus 1 may further include a temperature sensor 144. The temperature sensor 144 may be provided in the excitation electrode 14 or the upper electrode 142. The temperature sensor 144 includes, for example, a thermocouple. The temperature sensor 144 measures the temperature of the excitation electrode 14. In the plasma processing apparatus 1, the heater power supply 22 and a plurality of fans (described later) are controlled by the control unit 2 to reduce the difference between the temperature measured by the temperature sensor 144 and a target temperature value of the excitation electrode 14.

[0018] The control unit 2 is a computer device including a processor, a storage unit such as a memory, and a communication interface. The control unit 2 is configured to execute a control program and control each unit of the plasma processing apparatus 1 in accordance with recipe data.

[0019] The resonator 30 is provided on the excitation electrode 14. The resonator 30 is electromagnetically coupled to the emitter 16. The resonator 30 provides a waveguide 32. The resonator 30 includes a conductor portion 31 that defines the waveguide 32. The conductor portion 31 is made of a conductive material such as a metal.

[0020] The resonator 30 includes a first end 301 and a second end 302. The first end 301 is one end of the waveguide 32, and the second end 302 is the other end of the waveguide 32. The resonator 30 is configured to reflect and resonate electromagnetic waves propagating within the waveguide 32 at the first end 301 and the second end 302. The electromagnetic waves resonating within the resonator 30 are supplied to the emission portion 16 from a plurality of slots 302s (described later) and emitted into the plasma generation space.

[0021] The plasma processing apparatus 1 may further include a high-frequency power supply 34. The high-frequency power supply 34 is configured to generate high-frequency power. The electromagnetic waves introduced into the plasma generation space are generated based on the high-frequency power generated by the high-frequency power supply 34. The high-frequency power supply 34 may be directly connected to the resonator 30 using a coaxial line. That is, the high-frequency power supply 34 may be coupled to the waveguide of the resonator 30 without an impedance matching box. The coaxial line may include a connector 36 as a connection portion to the resonator 30. The connector 36 may be connected to the resonator 30 so as to introduce the electromagnetic waves into the resonator 30 from the uppermost layer of the multiple layers 320 of the waveguide 32 described below. In this case, the inner conductor of the connector 36 is connected to a conductor plate 31p (described below) that defines the uppermost layer from below, and the outer conductor of the connector 36 is connected to a conductor plate 31p (upper wall 31u) that defines the uppermost layer from above.

[0022] The conductor portion 31 of the resonator 30 includes a first portion 311 and a second portion 312. The first portion 311 includes a position from the first end 301 of the waveguide 32 to a position ¼ of the guide wavelength of the electromagnetic wave in the resonator 30. The second portion 312 is a portion of the conductor portion 31 other than the first portion 311. The second portion 312 may be all portions of the conductor portion 31 other than the first portion 311. The first portion 311 is formed from the first conductor. The second portion 312 is formed from the second conductor. The thermal conductivity of the first conductor is lower than the thermal conductivity of the second conductor. Therefore, the electrical conductivity of the first conductor is lower than the electrical conductivity of the second conductor. The first conductor includes, for example, stainless steel or brass. The second conductor includes, for example, aluminum or copper. Note that the first portion 311 may include a main body formed from the first conductor and a film covering the surface of the main body. This film may have an electrical conductivity greater than that of the first conductor, and may be made of, for example, silver, copper, gold, or the like.

[0023] In the plasma processing apparatus 1, the first portion 311 of the resonator 30 has a low thermal conductivity, so that heat conduction from the excitation electrode 14 through the resonator 30 is suppressed. Therefore, the power consumption of the heater power supply 22 is suppressed. Furthermore, in the first portion 311, the voltage of the standing wave is maximized and the current of the standing wave is minimized. Therefore, according to the plasma processing apparatus 1, the current loss in the resonator 30 is suppressed.

[0024] In one embodiment, the waveguide 32 may have a folded structure including multiple folded portions, in which case the first portion 311 may extend along one of the multiple folded portions.

[0025] In one embodiment, the waveguide 32 may be configured axially symmetric or rotationally symmetric with respect to the axis AX. Furthermore, in one embodiment, the conductor portion 31 may include an inner portion 31i (or inner peripheral portion), an outer portion 31o (or outer peripheral portion), and a plurality of conductor plates 31p. The inner portion 31i and the outer portion 31o extend coaxially with respect to the axis AX. Each of the inner portion 31i and the outer portion 31o may have a substantially cylindrical shape whose central axis is the axis AX. The plurality of conductor plates 31p extend in radial directions with respect to the axis AX and are arranged parallel to one another in the vertical direction, which is the direction in which the axis AX extends.

[0026] The waveguide 32 may also include multiple layers 320. The multiple layers 320 extend in radial directions relative to the axis AX between the inner portion 31i and the outer portion 31o, and are arranged alternately with the multiple conductor plates 31p. Each of the multiple layers 320 is connected to the layer above it at one of multiple folded portions along the inner portion 31i or the outer portion 31o.

[0027] In one embodiment, the first end 301 is provided above the second end 302. The first end 301 is provided by the outer portion 31o of the resonator 30. The first end 301 is the outer peripheral edge of the uppermost layer of the multiple layers 320 and surrounds the uppermost layer. The second end 302 is provided by the outer portion 31o of the resonator 30. The second end 302 is the outer peripheral edge of the lowermost layer of the multiple layers 320 and surrounds the lowermost layer. As shown in FIG. 4 , a plurality of slots 302s are formed in the lowermost conductor plate 31b, which defines the lowermost layer of the multiple conductor plates 31p from below. The plurality of slots 302s are arranged near or along the second end 302. The plurality of slots 302s are coupled to the emitter 16, externally of the excitation electrode 14. The plurality of slots 302s extend circumferentially around the axis AX above the emitter 16. The plurality of slots 302s extend in the circumferential direction relative to the axis AX and are arranged along the circumferential direction. The plurality of slots 302s are arranged alternately with the plurality of portions 302r in the conductive plate 31b. In this resonator 30, the electromagnetic wave is reflected at the second end 302 toward the first end 301. Furthermore, a portion of the electromagnetic wave propagating in the resonator 30 is coupled to the emission portion 16 through the plurality of slots 302s. In this embodiment, the first portion 311 is part of the outer portion 31o and surrounds one or more intermediate layers 320 of the plurality of layers 320.

[0028] In one embodiment, the inner portion 31i may be formed of a cylindrical conductive wall extending between vertically adjacent conductive plates 31p. The outer portion 31o may be composed of a plurality of columns 33. The columns 33 are arranged in the circumferential direction about the axis AX in the outer portion 31o between vertically adjacent conductive plates 31p. Each of the columns 33 is aligned with a corresponding column 33 along the vertical direction. In this embodiment, the first portion 311 is composed of a plurality of columns 33 (a plurality of columns 331 in the figure) surrounding one or more intermediate layers 320 among the plurality of layers 320. In this embodiment, the thickness (radial thickness) of the conductive wall constituting the inner portion 31i may be thinner than the thickness (radial thickness) of the outer portion 31o. This suppresses heat conduction from the excitation electrode 14 via the inner portion 31i.

[0029] The plurality of columns 33 may be cylindrical. In this case, a bolt 70 may be passed through the inner holes of the plurality of columns 33 aligned along the vertical direction. The lower end of the bolt 70 may be screwed into the lowest conductor plate 31b of the plurality of conductor plates 31p. A washer 71 and a nut 72 may be attached to the upper end of the bolt 70, and a coil spring 73 may be provided between the washer 71 and the upper wall 31u.

[0030] In one embodiment, the plasma processing apparatus 1 may further include a thin shield plate 30s. The thin shield plate 30s is made of a metal such as stainless steel. The thin shield plate 30s has a cylindrical shape and surrounds the outer portion 31o of the resonator 30. The thin shield plate 30s suppresses leakage of electromagnetic waves from the resonator 30.

[0031] In one embodiment, the plasma processing apparatus 1 may further include at least one conductive member 68. The conductive member 68 is provided between the resonator 30 and the excitation electrode 14 so as to form a gap between the resonator 30 and the excitation electrode 14. The conductive member 68 is made of a metal such as stainless steel. The conductive member 68 may have elasticity. The conductive member 68 is, for example, a shield spiral made of metal. The conductive member 68 suppresses heat transfer between the resonator 30 and the excitation electrode 14.

[0032] The conductive member 68 is sandwiched between the conductor plate 31b and the excitation electrode 14. As a result, the conductive member 68 electrically connects the resonator 30 to the excitation electrode 14. The conductive members 68 may be arranged to form a ring around the axis line AX. In the illustrated example, two conductive members 68 are arranged in a ring shape around the axis line AX as the at least one conductive member 68. The conductive members 68 may be arranged along a portion of the resonator 30 where a high-frequency current flows. In the illustrated example, the two conductive members 68 are arranged along a pair of edges of each of the multiple slots 302s.

[0033] In one embodiment, as shown in Fig. 3, at least one of the plurality of conductive plates 31p may have a plurality of slits SL formed therein. The plurality of slits SL penetrates the at least one conductive plate 31p in the thickness direction. The plurality of slits SL are arranged along the circumferential direction around the axis AX and extend in radial directions relative to the axis AX. The plurality of slits SL suppresses propagation of higher harmonics of electromagnetic waves in the circumferential direction. Furthermore, pressure loss of the heat transfer medium, which will be described later, within the waveguide 32 is suppressed.

[0034] The plasma processing apparatus 1 may further include a temperature regulator 18. The temperature regulator 18 is configured to supply a heat medium (for example, a gas such as air) along the upper surface of the excitation electrode 14.

[0035] The temperature regulator 18 includes a plurality of fans 40. The temperature regulator 18 provides a flow path 42. The plurality of fans 40 are arranged at approximately equal intervals around the axis line AX above the excitation electrode 14. The plurality of fans 40 are configured to form a flow of the heat medium within the flow path 42. In the plasma processing apparatus 1, each of the plurality of fans 40 can suck in and exhaust the heat medium from the flow path 42.

[0036] The flow path 42 extends from the opening 42a to the plurality of openings 42b. The opening 42a is an inlet for the heat medium into the flow path 42. The plurality of openings 42b are outlets for the heat medium from the flow path 42. Each of the plurality of openings 42b opens directly below a corresponding one of the plurality of fans 40.

[0037] The flow path 42 is axially symmetric or rotationally symmetric with respect to the axis line AX. The flow path 42 includes a partial flow path 421 and a partial flow path 422. The flow path 42 may further include a partial flow path 423.

[0038] The partial flow path 421 extends along the upper surface of the excitation electrode 14. The partial flow path 421 is provided between the conductor plate 31b of the resonator 30 and the excitation electrode 14. The partial flow path 421 extends in a radial direction from the axis AX. The partial flow paths 422 are connected to the partial flow paths 421 via a plurality of communication holes 14c formed in the upper electrode 142. The partial flow paths 422 extend alternately in opposite directions between the plurality of fans 40 and the partial flow paths 421. The opposite directions are a direction approaching the axis AX and a radial direction relative to the axis AX. The opposite directions are perpendicular to the axis AX. In one embodiment, the partial flow paths 422 of the temperature regulator 18 are formed from the waveguide 32 of the resonator 30. Therefore, the resonator 30 constitutes a heat exchanger for the excitation electrode 14.

[0039] The partial flow path 423 extends from the opening 42a to the partial flow path 421. The partial flow path 423 is provided inside the inner portion 31i of the resonator 30. The partial flow path 423 may have the axis line AX as its central axis line. That is, the partial flow path 423 may extend vertically along the axis line AX to the partial flow path 421.

[0040] In the plasma processing apparatus 1, the heat medium taken in through the opening 42a is supplied from the partial flow path 423 to the partial flow path 421, and flows within the partial flow path 421 along the upper surface of the excitation electrode 14. As a result, heat exchange occurs between the excitation electrode 14 and the heat medium. The heat medium then flows from the partial flow path 421 to the partial flow path 422, and is discharged to the outside of the plasma processing apparatus 1 through the multiple openings 42b by the multiple fans 40.

[0041] In one embodiment, a heater 66 may be provided inside the inner portion 31i of the resonator 30. In this embodiment, a heat medium preheated by the heater 66 is supplied to the partial flow path 421. The heater 66 can preheat the heat medium to a temperature similar to the temperature of the excitation electrode 14 (e.g., 180°C), for example. This improves the temperature controllability of the excitation electrode 14.

[0042] In one embodiment, the plasma processing apparatus 1 may further include a gas pipe 64. The gas pipe 64 extends vertically inside the inner portion 31i. The central axis of the gas pipe 64 may be located on the axis AX. The gas pipe 64 is connected between the gas diffusion chamber 14d and the gas supply unit 20. The heater 66 described above may surround the gas pipe 64. Alternatively, the heater 66 may be attached to the outer periphery of the gas pipe 64.

[0043] The temperature regulator 18 may further include a cooling unit 50. The cooling unit 50 may form a part of the partial flow path 422. Specifically, the cooling unit 50 includes a wall 50w, and provides a refrigerant flow path 50f within the wall 50w. A refrigerant is supplied to the refrigerant flow path 50f from a chiller unit. According to the temperature regulator 18, the heat medium cooled by the cooling unit 50 in the partial flow path 422 is discharged to the outside through the multiple fans 40. Note that the wall 50w may be the upper wall 31u. The wall 50w may not be the upper wall 31u, but may be any of the multiple conductor plates 31p of the resonator 30.

[0044] In one embodiment, the length (height) of the waveguide 32 in the vertical direction of the top layer of the multiple layers 320 in the waveguide 32 may be longer than the lengths (heights) of the waveguide 32 in the vertical direction of the other layers of the multiple layers 320. Since the top layer is provided near the multiple fans 40, the flow velocity of the heat medium in the top layer is high. According to this embodiment, it is possible to suppress pressure loss of the heat medium in the top layer where the flow velocity is high.

[0045] In one embodiment, the excitation electrode 14 may have a plurality of fins 14f. The plurality of fins 14f are provided by the upper electrode 142. The plurality of fins 14f protrude upward, extend in a radial direction relative to the axis line AX, and are arranged in a circumferential direction around the axis line AX. Each of the plurality of communication holes 14c is connected to a gap between two adjacent fins of the plurality of fins 14f. The plurality of fins 14f promotes heat exchange between the excitation electrode 14 and the heat medium.

[0046] A plasma processing apparatus according to another exemplary embodiment will be described below with reference to FIGS. 6 to 10. FIG. 6 is a diagram showing a plasma processing apparatus according to another exemplary embodiment. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6. FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 6. FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 6. FIG. 10 is a cross-sectional view taken along line XX in FIG. 6. A plasma processing apparatus 1B shown in FIGS. 6 to 10 will be described below from the perspective of differences from the plasma processing apparatus 1.

[0047] The plasma processing apparatus 1B includes a resonator 30B instead of the resonator 30. The resonator 30B is provided above the excitation electrode 14. Like the resonator 30, the resonator 30B includes a waveguide 32 defined by a conductor portion 31. In the resonator 30B, the waveguide 32 also includes a plurality of layers 320. Like the conductor portion 31 of the resonator 30, the conductor portion 31 of the resonator 30B also includes a first portion 311 and a second portion 312.

[0048] In the temperature regulator 18 of the plasma processing apparatus 1B, the flow path 42 is formed in substantially the same manner as the flow path 42 of the plasma processing apparatus 1. Furthermore, the partial flow path 422 of the temperature regulator 18 of the plasma processing apparatus 1B is formed from the waveguide 32 of the resonator 30B. However, in the temperature regulator 18 of the plasma processing apparatus 1B, the partial flow path 422 is connected to the partial flow path 421 via a plurality of communication holes 42c formed in the conductor plate 31b. The plurality of communication holes 42c penetrate the conductor plate 31b and are arranged in the circumferential direction around the axis AX.

[0049] In the plasma processing apparatus 1B, the heat medium is supplied from the multiple fans 40 to the partial flow path 421 via the multiple openings 42b and the partial flow paths 422, and flows within the partial flow path 421 along the upper surface of the excitation electrode 14. As a result, heat exchange occurs between the excitation electrode 14 and the heat medium. Then, the heat medium flows from the partial flow path 421 to the partial flow path 423. The heat medium is discharged from the partial flow path 423 to the outside of the plasma processing apparatus 1B via the opening 42a.

[0050] In the plasma processing apparatus 1B, the upper wall 31u of the resonator 30B may have a plurality of fins 31f. The fins 31f protrude upward. The fins 31f extend in radial directions relative to the axis AX and are arranged circumferentially around the axis AX. A heat insulating plate 80 may be disposed on the fins 31f. The heat insulating plate 80 is made of, for example, polyimide.

[0051] The fins 31f provide a plurality of flow paths therebetween. The flow paths provided by the fins 31f extend radially with respect to the axis AX and are arranged circumferentially around the axis AX. The partial flow paths 423 and the openings 42a are connected to each other via the flow paths provided by the fins 31f. According to this embodiment, the heat medium is cooled by the fins 31f and then discharged to the outside of the plasma processing apparatus 1B through the openings 42a.

[0052] In the plasma processing apparatus 1B, the outer portion 31o has a generally cylindrical shape and has the axis AX as its central axis. In the plasma processing apparatus 1B, the outer portion 31o may extend along each side of a polygon in a cross section perpendicular to the axis AX. That is, the outer portion 31o may have a polygonal tube shape. The outer portion 31o may be formed of a plurality of plate-like bodies 315 between adjacent conductor plates 31p in the vertical direction. Each of the plurality of plate-like bodies 315 is formed from a metal. Each of the plurality of plate-like bodies 315 may be a flat plate. Each of the plurality of plate-like bodies 315 extends along a corresponding side of the polygon in a cross section perpendicular to the axis AX.

[0053] In the plasma processing apparatus 1B as well, the plurality of plate-like bodies 315 constituting the first portion 311 are formed from the first conductor described above. The second portion 312 is formed from the second conductor described above. The second portion 312 includes the plurality of plate-like bodies 315 constituting the second portion 312. In the plasma processing apparatus 1B as well, the second portion 312 may be all portions of the conductor portion 31 other than the first portion 311.

[0054] In the plasma processing apparatus 1B, the first portion 311 has a low thermal conductivity, so that heat conduction from the excitation electrode 14 through the resonator 30B is suppressed. This reduces the power consumption of the heater power supply 22. Furthermore, in the first portion 311, the voltage of the standing wave is maximized and the current of the standing wave is minimized. Therefore, the plasma processing apparatus 1B reduces current loss in the resonator 30B.

[0055] In the plasma processing apparatus 1B, each of the plurality of plate-like bodies 315 is fixed to the upper and lower conductor plates 31p by one or more screws 81. The one or more screws 81 may be formed from the first conductor described above. In this case, the difference in thermal expansion coefficient between each of the plurality of plate-like bodies 315 constituting the first portion 311 and the one or more screws 81 is reduced. Therefore, damage to the one or more screws 81 is suppressed.

[0056] A plasma processing apparatus according to yet another exemplary embodiment will be described below with reference to Fig. 11. Fig. 11 is a diagram showing a plasma processing apparatus according to yet another exemplary embodiment. A plasma processing apparatus 1C shown in Fig. 11 will be described below from the viewpoint of differences from the plasma processing apparatus 1.

[0057] The plasma processing apparatus 1C further includes an electrode 60. The electrode 60 is another excitation electrode. The electrode 60 has a generally disk shape and is disposed so as to close the opening at the upper end of the chamber 10. The electrode 60 has a plurality of holes 60h. The plurality of holes 60h penetrate the electrode 60 in the thickness direction. The excitation electrode 14 is disposed above the electrode 60. The excitation electrode 14 and the electrode 60 form a plasma generation space 60p therebetween. The emission section 16 surrounds the plasma generation space 60p and is sandwiched between the excitation electrode 14 and the electrode 60. In the plasma processing apparatus 1C, the plasma generation space 60p is disposed above the processing space 10s, away from the processing space 10s.

[0058] In the plasma processing apparatus 1C, gas from the gas supply unit 20 is supplied to the plasma generation space 60p via the gas diffusion chamber 14d and the plurality of gas holes 14h. In the plasma generation space 60p, plasma is generated from the gas by electromagnetic waves introduced into the plasma generation space 60p from the emission unit 16. Active species in the plasma generated in the plasma generation space 60p are supplied to the processing space 10s through the plurality of holes 60h.

[0059] The plasma processing apparatus 1C also includes a resonator 30C instead of the resonator 30. The resonator 30C is provided above the excitation electrode 14. Like the resonator 30, the resonator 30C includes a waveguide 32 defined by a conductor portion 31. In the resonator 30C, the waveguide 32 also includes a plurality of layers 320. Like the conductor portion 31 of the resonator 30, the conductor portion 31 of the resonator 30 also includes a first portion 311 and a second portion 312. However, in the resonator 30C, the first end 301, i.e., the end opposite to one end of the waveguide 32, is located at the radial center of the plasma generation space 60p.

[0060] In the resonator 30C, the outer portion 31o may be formed in a substantially cylindrical shape. In the resonator 30C, the first portion 311 is part of the inner portion 31i and extends inside one or more intermediate layers 320 among the multiple layers 320. In the plasma processing apparatus 1C as well, the first portion 311 is formed from the first conductor described above. Moreover, the second portion 312 is formed from the second conductor described above. In the plasma processing apparatus 1C as well, the second portion 312 may be all portions of the conductor portion 31 other than the first portion 311.

[0061] In the plasma processing apparatus 1C, the thermal conductivity of the first portion 311 is also low, so that heat conduction from the excitation electrode 14 via the resonator 30C is suppressed. This reduces the power consumption of the heater power supply 22. Furthermore, in the first portion 311, the voltage of the standing wave is maximized and the current of the standing wave is minimized. Therefore, with the plasma processing apparatus 1C, current loss in the resonator 30C is suppressed.

[0062] In the temperature regulator 18 of the plasma processing apparatus 1C, the flow path 42 includes a partial flow path 421 and a partial flow path 422. The partial flow path 422 of the temperature regulator 18 of the plasma processing apparatus 1C is formed from the waveguide 32 of the resonator 30C. In the temperature regulator 18 of the plasma processing apparatus 1C, the flow path 42 extends from a plurality of openings 42b to a plurality of openings 42a. The plurality of openings 42b are inlets for the heat medium to the flow path 42 and are connected to the partial flow path 422. Each of the plurality of openings 42b opens directly below a corresponding one of the plurality of fans 40. The plurality of openings 42a are outlets for the heat medium from the flow path 42 and are connected to the partial flow path 421. The plurality of openings 42a are arranged in the circumferential direction around the axis line AX. In one embodiment, the plurality of openings 42a are formed in the outer portion 31o of the resonator 30C.

[0063] In the plasma processing apparatus 1C, the heat medium is supplied from the multiple fans 40 to the partial flow passage 421 via the multiple openings 42b and the partial flow passages 422, and flows within the partial flow passage 421 along the upper surface of the excitation electrode 14. As a result, heat exchange occurs between the excitation electrode 14 and the heat medium. The heat medium is then discharged from the partial flow passage 421 to the outside of the plasma processing apparatus 1C via the multiple openings 42a.

[0064] Although various exemplary embodiments have been described above, the present invention is not limited to the above-described exemplary embodiments, and various additions, omissions, substitutions, and modifications may be made. Furthermore, elements in different embodiments may be combined to form other embodiments.

[0065] Various exemplary embodiments included in the present disclosure are now described in [E1] to [E12] below.

[0066] [E1] A plasma processing apparatus comprising: a chamber providing a processing space therein; a substrate support provided in the processing space; an excitation electrode provided above the substrate support; an emitter provided to emit electromagnetic waves into a plasma generation space below the excitation electrode; and a resonator provided on the excitation electrode and electromagnetically coupled to the emitter, wherein the resonator includes a conductor portion defining a waveguide thereof, the conductor portion being formed from a first conductor in a first portion including a position from one end of the waveguide to a position ¼ of the guide wavelength of the electromagnetic wave in the resonator, and being formed from a second conductor in a second portion other than the first portion, and the thermal conductivity of the first conductor being lower than the thermal conductivity of the second conductor.

[0067] [E2] The plasma processing apparatus according to E1, wherein the waveguide has a structure including a plurality of folded portions, and the first portion extends along one of the plurality of folded portions.

[0068] [E3] The plasma processing apparatus described in E2, wherein the emission section extends around a central axis of the chamber and the excitation electrode, the conductor section includes an inner section and an outer section extending coaxially with respect to the central axis, and a plurality of conductor plates arranged parallel to each other along a vertical direction in which the central axis extends, the waveguide includes a plurality of layers extending between the outer section and the inner section and arranged alternately with the plurality of conductor plates, and each of the plurality of layers of the waveguide is connected to the layer above it at one of the plurality of folding sections along the inner section or the outer section.

[0069] [E4] The plasma processing apparatus according to E3, wherein the first portion is a part of the outer portion.

[0070] [E5] The plasma processing apparatus according to E3 or E4, wherein the one end is an outer peripheral end of an uppermost layer of the plurality of layers, the waveguide further includes the other end being an outer peripheral end of a lowermost layer of the plurality of layers, and the plasma generation space is below the excitation electrode and within the processing space.

[0071] [E6] The plasma processing apparatus according to E3, wherein the first portion is a part of the inner portion.

[0072] [E7] The plasma processing apparatus according to E6, further comprising another electrode interposed between the excitation electrode and the processing space and providing a plurality of holes connecting the plasma generation space and the processing space, wherein the emission section is provided between the excitation electrode and the another electrode.

[0073] [E8] The plasma processing apparatus according to any one of E3 to E7, wherein the thickness of the wall constituting the inner portion is thinner than the thickness of the wall constituting the outer portion.

[0074] [E9] The plasma processing apparatus according to any one of E1 to E8, wherein the excitation electrode has a heating mechanism.

[0075] [E10] The plasma processing apparatus according to E9, wherein the heating mechanism is an electric heater.

[0076] [E11] The plasma processing apparatus according to any one of E1 to E10, further comprising a fan configured to form a flow of gas through the waveguide between the surface of the excitation electrode and the outside of the resonator.

[0077] [E12] The plasma processing apparatus according to any one of E1 to E11, wherein the first conductor includes stainless steel or brass, and the second conductor includes aluminum or copper.

[0078] From the foregoing, it will be understood that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the appended claims.

[0079] 1...plasma processing apparatus, 10...chamber, 12...substrate support portion, 14...excitation electrode, 16...emission portion, 30...resonator, 31...conductor portion, 311...first portion, 312...second portion, 32...waveguide.

Claims

1. A plasma processing apparatus comprising: a chamber providing a processing space therein; a substrate support section provided within the processing space; an excitation electrode provided above the substrate support section; an emitter section provided to emit electromagnetic waves into a plasma generation space below the excitation electrode; and a resonator provided on the excitation electrode and electromagnetically coupled to the emitter section, wherein the resonator includes a conductor section defining a waveguide thereof, the conductor section being formed from a first conductor in a first section including a position from one end of the waveguide to a position that is ¼ of a guide wavelength of the electromagnetic wave in the resonator, and being formed from a second conductor in a second section other than the first section, and the thermal conductivity of the first conductor being smaller than the thermal conductivity of the second conductor.

2. The plasma processing apparatus according to claim 1, wherein the waveguide has a structure including a plurality of folded portions, and the first portion extends along one of the plurality of folded portions.

3. The plasma processing apparatus of claim 2, wherein the emission section extends around a central axis of the chamber and the excitation electrode, the conductor section includes an inner section and an outer section extending coaxially about the central axis, and a plurality of conductor plates arranged parallel to each other along a vertical direction in which the central axis extends, the waveguide includes a plurality of layers extending between the outer section and the inner section and arranged alternating with the plurality of conductor plates, and each of the plurality of layers of the waveguide is connected to the layer above it at one of the plurality of folds along the inner section or the outer section.

4. The plasma processing apparatus of claim 3, wherein the first portion is a part of the outer portion.

5. The plasma processing apparatus according to claim 4, wherein the one end is an outer peripheral end of an uppermost layer of the plurality of layers, the waveguide further includes the other end being an outer peripheral end of a lowermost layer of the plurality of layers, and the plasma generation space is below the excitation electrode and within the processing space.

6. The plasma processing apparatus of claim 3, wherein said first portion is a part of said inner portion.

7. The plasma processing apparatus according to claim 6, further comprising another electrode interposed between the excitation electrode and the processing space and providing a plurality of holes connecting the plasma generation space and the processing space, the emission section being provided between the excitation electrode and the another electrode.

8. A plasma processing apparatus according to any one of claims 3 to 7, wherein the thickness of the wall constituting the inner portion is thinner than the thickness of the wall constituting the outer portion.

9. The plasma processing apparatus according to any one of claims 1 to 7, wherein the excitation electrode has a heating mechanism.

10. The plasma processing apparatus according to claim 9, wherein the heating mechanism is an electric heater.

11. The plasma processing apparatus of claim 1, further comprising a fan configured to create a flow of gas through the waveguide between a surface of the excitation electrode and an exterior of the resonator.

12. The plasma processing apparatus according to any one of claims 1 to 7, wherein the first conductor includes stainless steel or brass, and the second conductor includes aluminum or copper.

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