Plasma processing apparatus

Abstract

To provide a technique of suppressing electrical discharge from a chalk structure in a plasma processing apparatus.SOLUTION: A plasma processing apparatus disclosed herein comprises a chamber, an introduction part, and a choke structure. The introduction part is provided so that radio waves are introduced into the chamber therefrom. The choke structure is provided in a wall of the chamber. The choke structure is configured to suppress propagation of the radio waves downstream along an internal surface of the chamber from a position at which the choke structure is provided. The choke structure includes a first portion having a slit shape and a second portion. The first portion is connected to a space in the chamber. The second portion is extended from the first portion in the wall of the chamber. A length of the second portion along a direction of magnetic fields of electromagnetic waves in the second portion is longer than a length of the first portion along a direction of magnetic fields of electromagnetic waves in the first direction.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Plasma processing apparatuses are used in plasma processing of substrates. One type of plasma processing apparatus is described in Patent Document 1 below. The plasma processing apparatus described in Patent Document 1 uses a high frequency in the UHF band or the VHF band as an electromagnetic wave for exciting plasma. The electromagnetic wave introduced into the chamber propagates along the wall surface in the chamber as a surface wave. The plasma processing apparatus described in Patent Document 1 has a choke portion in order to suppress the propagation of the electromagnetic wave to unnecessary portions in the chamber.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a technique for suppressing discharge in a choke structure of a plasma processing apparatus.

Means for Solving the Problems

[0005] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, an introduction part, and a choke structure. The introduction part is provided such that electromagnetic waves are introduced into the chamber therefrom. The choke structure is provided on the wall of the chamber. The choke structure is configured to suppress the propagation of electromagnetic waves downstream along the inner wall surface of the chamber from the location where it is provided. The choke structure includes a slit-shaped first portion and a second portion. The first portion is connected to the space inside the chamber. The second portion extends from the first portion within the wall of the chamber. The length of the second portion along the direction of the electric field of the electromagnetic wave in the second portion is longer than the length of the first portion along the direction of the electric field of the electromagnetic wave in the first portion.

Effect of the Invention

[0006] According to one exemplary embodiment, it becomes possible to suppress discharge in the choke structure of the plasma processing apparatus.

Brief Description of the Drawings

[0007]

Figure 1

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Embodiments for Carrying Out the Invention

[0008] Hereinafter, various exemplary embodiments will be described.

[0009] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, an introduction part, and a choke structure. The introduction part is provided such that electromagnetic waves are introduced into the chamber therefrom. The choke structure is provided on the wall of the chamber. The choke structure is configured to suppress the propagation of electromagnetic waves downstream along the inner wall surface of the chamber from the location where it is provided. The choke structure includes a slit-shaped first part and a second part. The first part is connected to the space inside the chamber. The second part extends from the first part within the wall of the chamber. The length of the second part along the direction of the electric field of the electromagnetic wave in the second part is longer than the length of the first part along the direction of the electric field of the electromagnetic wave in the first part.

[0010] In the above embodiment, for the first part, the second part is expanded along the direction of the electric field of the electromagnetic wave. Therefore, the intensity of the electric field in the second part is reduced. Thus, according to the above embodiment, it is possible to suppress the discharge in the choke structure.

[0011] In one exemplary embodiment, the length of the second part along the propagation direction of the electromagnetic wave in the second part may be longer than the length of the first part along the propagation direction of the electromagnetic wave in the first part.

[0012] In one exemplary embodiment, the propagation direction of the electromagnetic wave in the first part and the propagation direction of the electromagnetic wave in the second part may be the same.

[0013] In one exemplary embodiment, the choke structure may further include a dielectric part provided in the first part.

[0014] In one exemplary embodiment, the choke structure may further include a dielectric part provided in the second part.

[0015] In one exemplary embodiment, the choke structure may be provided on the side wall of the chamber. The side wall may include an annular exhaust duct. The annular exhaust duct provides an annular exhaust passage. The annular exhaust passage extends in the circumferential direction with respect to the central axis of the side wall and communicates with the space inside the chamber. The first part is formed on the wall defining the annular exhaust duct and extends in the circumferential direction with respect to the central axis. The second part is the annular exhaust passage.

[0016] In one exemplary embodiment, the side wall of the chamber may include a first wall member and a second wall member. The first wall member extends above the first part. The second wall member is separable from the first wall member and extends below the first part of the choke structure. The first wall member and the second wall member may elastically sandwich a dielectric part disposed therebetween.

[0017] In one exemplary embodiment, the sidewall of the chamber may further include a third wall member and a fourth wall member. The third wall member is separable from the first wall member and the second wall member, and together with the first wall member and the second wall member, constitutes an annular exhaust duct. The fourth wall member extends below the annular exhaust duct. The first wall member is provided above the second wall member and the third wall member, and defines an annular exhaust passage from above. The second wall member extends inside the third wall member and, together with the third wall member, defines an annular exhaust passage from below. The second wall member may press the dielectric part by the reaction force from the O-ring and / or the spiral spring gasket.

[0018] In one exemplary embodiment, the annular exhaust duct may provide three or more recesses. The three or more recesses extend radially inward from the inner peripheral surface of the annular exhaust duct that defines the annular exhaust passage, and are arranged at equal intervals along the circumferential direction. The dielectric part may include three or more protrusions arranged in the three or more recesses.

[0019] In one exemplary embodiment, the dielectric part provided in the first portion may extend into the annular exhaust passage.

[0020] In one exemplary embodiment, the dielectric part may include a plurality of first members and a plurality of second members. The plurality of first members and the plurality of second members may be alternately arranged along the circumferential direction in the first portion. The plurality of first members may be fitted to the first portion. The thickness of each of the plurality of second members may be smaller than the thickness of each of the plurality of first members.

[0021] In one exemplary embodiment, the insulating member may have an annular shape. The insulating member may provide a first cut portion extending from the inner peripheral side to the outer peripheral side of the insulating member and a second cut portion extending from the outer peripheral side to the inner peripheral side of the insulating member.

[0022] In one exemplary embodiment, the first cut portion and the second cut portion may be provided within an angular range of 90 degrees or less with respect to the center of the insulating member. That is, the first cut portion may be provided in the vicinity of the second cut portion that pairs with it.

[0023] In one exemplary embodiment, the insulating member may provide a plurality of pairs of cut portions each including a first cut portion and a second cut portion. The plurality of pairs of cut portions are arranged along the circumferential direction. The circumferential interval between the first cut portion and the second cut portion in each of the plurality of pairs of cut portions may be narrower than the circumferential interval of the plurality of pairs of cut portions.

[0024] In one exemplary embodiment, the plasma processing apparatus may further include an elastic ring that presses the insulating member against the wall where the first portion is formed.

[0025] In one exemplary embodiment, the choke structure may further include an insulating member provided to at least partially cover the dielectric portion in the annular exhaust passage.

[0026] In one exemplary embodiment, the insulating member may cover a portion excluding the end portion of the dielectric portion or the entire dielectric portion in the annular exhaust passage.

[0027] In one exemplary embodiment, the insulating member may include a plurality of portions separated from each other in the circumferential direction.

[0028] In one exemplary embodiment, the insulating member may have elasticity.

[0029] In one exemplary embodiment, the annular exhaust duct may include an outer peripheral wall that provides an opening. Another exhaust duct may be connected to the annular exhaust duct. The exhaust passage of the another exhaust duct may be connected to the annular exhaust passage through the opening of the outer peripheral wall of the annular exhaust duct. A short-circuit portion may be provided in the opening so as to electrically connect a pair of edges defining the opening of the outer peripheral wall of the annular exhaust duct to each other.

[0030] In one exemplary embodiment, the second portion may be a cavity. The pressure in the second portion may be set to a pressure higher than the pressure in the space within the chamber.

[0031] In another exemplary embodiment, a plasma processing apparatus is also provided. The plasma processing apparatus includes a chamber, an introduction portion, and a choke structure. The introduction portion is provided such that electromagnetic waves are introduced into the chamber therefrom. The choke structure is provided on the wall of the chamber. The choke structure is configured to suppress the downstream propagation of electromagnetic waves along the inner wall surface of the chamber from the location where it is provided. The choke structure includes a slit-shaped first portion, a dielectric portion, and a second portion. The first portion is connected to the space within the chamber. The dielectric portion is provided within the first portion. The second portion extends from the first portion within the wall of the chamber. The second portion is a cavity, and the pressure in the second portion is set to a pressure higher than the pressure in the space within the chamber.

[0032] In one exemplary embodiment, the choke structure may provide a passage that communicates the second portion with the atmospheric space outside the chamber.

[0033] In one exemplary embodiment, the plasma processing apparatus may further include a gas supply portion configured to supply gas to the second portion. The gas may be a fluorine-containing gas.

[0034] In one exemplary embodiment, the choke structure is provided on the sidewall of the chamber. The first portion and the second portion may extend circumferentially with respect to the central axis of the sidewall.

[0035] Hereinafter, various exemplary embodiments will be described in detail with reference to the drawings. The same or corresponding parts in each drawing will be denoted by the same reference numerals.

[0036] FIG. 1 is a diagram schematically showing a plasma processing apparatus according to one exemplary embodiment. The plasma processing apparatus 1 shown in FIG. 1 includes a chamber 10, an introduction unit 14, and a choke structure 16.

[0037] The chamber 10 provides a substrate processing space 10s therein. The chamber 10 is formed of a metal such as aluminum and is grounded. The chamber 10 may have a substantially cylindrical shape that is open at its upper end. The central axis of each of the chamber 10 and the substrate 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 including a yttrium oxide film, a yttrium fluoride oxide film, a yttrium fluoride film, yttrium oxide, or yttrium fluoride.

[0038] The bottom of the chamber 10 provides an exhaust port 10e. An exhaust device is connected to the exhaust port 10e. The exhaust device may include a vacuum pump such as a dry pump and / or a turbo molecular pump and an automatic pressure control valve.

[0039] The plasma processing apparatus 1 may further include a substrate support 12. The substrate support 12 is provided in the substrate processing space 10s. The substrate support 12 is configured to support the substrate W placed on its upper surface substantially horizontally. The substrate support 12 has a substantially disk shape. The central axis of the substrate support 12 is the axis AX.

[0040] The introduction part 14 is provided so that electromagnetic waves are introduced into the chamber 10 therefrom. The introduction part 14 is formed of a dielectric such as quartz, aluminum nitride, or aluminum oxide. The introduction part 14 may have a substantially annular shape, and its central axis may be the axis AX. The electromagnetic waves introduced into the chamber 10 from the introduction part 14 are high-frequency waves such as VHF waves or UHF waves. The electromagnetic waves are generated by a high-frequency power source described later. The electromagnetic waves propagate through the waveguide part 18 to the introduction part 14 and are introduced into the chamber from the introduction part 14.

[0041] The waveguide part 18 provides a waveguide 18w. In one embodiment, the waveguide part 18 may include an upper electrode 22 and an upper wall 24. The upper electrode 22 is provided above the substrate support part 12. The upper electrode 22 is formed of a conductor such as aluminum and has a substantially disc shape. The central axis of the upper electrode 22 is the axis AX.

[0042] The upper wall 24 is formed of a conductor such as aluminum. The upper wall 24 is provided so as to cover the upper electrode 22 and forms a waveguide 18w between the upper electrode 22 and the upper wall 24. The upper wall 24 may include an upper part 24a and a side part 24b. The upper part 24a has a substantially disc shape, and its central axis is the axis AX. The upper part 24a extends above the upper electrode 22 and parallel to the upper surface of the upper electrode 22. The waveguide 18w is formed between the upper surface of the upper electrode 22 and the lower surface of the upper part 24a of the upper wall 24. The side part 24b has a substantially cylindrical shape, and its central axis is the axis AX. The side part 24b extends downward from the peripheral edge of the upper part 24a. The introduction part 14 is provided so as to fill the space between the inner peripheral surface of the side part 24b and the outer peripheral surface of the upper electrode 22. Note that the upper wall 24 can be disposed on the side wall 10a such that the lower end of the side part 24b contacts the side wall 10a of the chamber 10.

[0043] The plasma processing apparatus 1 further includes a high-frequency power source 30 and a matcher 32. The high-frequency power source 30 is configured to generate high-frequency power. The electromagnetic wave introduced into the chamber 10 is generated based on the high-frequency power generated by the high-frequency power source 30. The high-frequency power source 30 is connected to the upper electrode 22 via the matcher 32 and an electric line 34. The matcher 32 includes a matching circuit for matching the impedance of the load of the high-frequency power source 30 to the output impedance of the high-frequency power source 30. The electric line 34 extends downward from the matcher 32 and is connected to the center of the upper surface of the upper electrode 22. The electric line 34 may extend on the axis AX.

[0044] In one embodiment, the plasma processing apparatus 1 may further include a shower plate 26. The shower plate 26 is provided above the substrate support 12. The shower plate 26 has a substantially disk shape. The central axis of the shower plate 26 is the axis AX. The shower plate 26 may be formed of a conductor such as aluminum. The space between the outer peripheral surface of the shower plate 26 and the inner peripheral surface of the side portion 24b of the upper wall 24 is filled with the introduction portion 14. The introduction portion 14 and the shower plate 26 are provided so as to close the upper end opening of the chamber 10.

[0045] The shower plate 26 provides a plurality of gas holes 26h. The plurality of gas holes 26h penetrate the shower plate 26 in its plate thickness direction and open toward the substrate processing space 10s. An upper electrode 22 is provided on the shower plate 26. The upper electrode 22 and the shower plate 26 constitute a shower head 28. The upper electrode 22 and the shower plate 26 form a gas diffusion space 28a therebetween. The plurality of gas holes 26h extend downward from the gas diffusion space 28a.

[0046] A gas supply unit 36 is connected to the gas diffusion space 28a. The gas output from the gas supply unit 36 is supplied to the substrate processing space 10s through the gas diffusion space 28a and the plurality of gas holes 26h. The gas supplied by the gas supply unit 36 is selected according to the process performed in the substrate processing space 10s. The gas supplied by the gas supply unit 36 may include a film-forming gas. The gas supplied by the gas supply unit 36 may also include a cleaning gas used for cleaning the wall surface in the chamber 10.

[0047] Hereinafter, refer to FIG. 2 together with FIG. 1. FIG. 2 is a partial enlarged cross-sectional view of a choke structure in a plasma processing apparatus according to one exemplary embodiment. The choke structure 16 is provided on the wall of the chamber 10. The choke structure 16 is configured to suppress the propagation of electromagnetic waves downstream along the inner wall surface of the chamber 10 from the location where it is provided.

[0048] The choke structure 16 includes a slit-shaped first portion 161 and a second portion 162. The first portion 161 is connected to the substrate processing space 10s in the chamber 10. The second portion 162 extends from the first portion 161 within the wall of the chamber 10. The second portion 162 may provide a space that extends from the first portion 161 within the wall of the chamber 10.

[0049] The first portion 161 may include a dielectric portion 161d provided therein, that is, within the slit. The slit of the first portion 161 is filled with the dielectric portion 161d. Also, the second portion 162 may include a dielectric portion 162d provided therein. The space of the second portion 162 is filled with the dielectric portion 162d. Each of the dielectric portion 161d and the dielectric portion 162d is formed of a dielectric such as quartz, aluminum oxide, yttria, silicon carbide, or aluminum nitride.

[0050] The length H2 of the second portion 162 along the direction of the electric field of the electromagnetic wave in the second portion 162 is longer than the length H1 of the first portion 161 along the direction of the electric field of the electromagnetic wave in the first portion 161. In each of the first portion 161 and the second portion 162, the direction of the electric field of the electromagnetic wave is a direction orthogonal to the propagation direction of the electromagnetic wave.

[0051] Also, in the plasma processing apparatus 1, the length W2 of the second portion 162 along the propagation direction of the electromagnetic wave in the second portion 162 may be longer than the length W1 of the first portion 161 along the propagation direction of the electromagnetic wave in the first portion 161. Note that the sum of the length W1 and the length W2 is set so as to cancel out the electromagnetic wave propagating along the inner wall surface of the chamber 10 by the reflected wave returned from the choke structure 16. The reflected wave is generated when the electromagnetic wave is introduced from the first portion 161 into the choke structure 16 and reflected at the end surface (short-circuit surface) in the propagation direction of the second portion 162. The sum of the length W1 and the length W2 can be set to, for example, about 1 / 4 of the wavelength of the electromagnetic wave in the choke structure 16.

[0052] In one embodiment, as shown in FIG. 1, the choke structure 16 is provided on the side wall 10a of the chamber 10. The choke structure 16 is provided below the introduction portion 14. The first portion 161 and its slit have an annular shape and extend in the circumferential direction with respect to the central axis of the side wall 10a, that is, the axis AX. Also, the second portion 162 and its space have an annular shape and extend in the circumferential direction with respect to the axis AX. The second portion 162 extends radially outside with respect to the first portion 161. Also, each of the dielectric portion 161d and the dielectric portion 162d has an annular shape and extends in the circumferential direction with respect to the axis AX. In the plasma processing apparatus 1, the propagation direction of the electromagnetic wave in each of the first portion 161 and the second portion 162 is a radial direction with respect to the axis AX and is the same direction. Also, in each of the first portion 161 and the second portion 162, the direction of the electric field of the electromagnetic wave is a vertical direction.

[0053] In the plasma processing apparatus 1, the electromagnetic wave introduced into the chamber 10 from the introduction part 14 propagates along the lower surface of the shower plate 26 and excites the gas introduced into the chamber 10 from the plurality of gas holes 26h. As a result, plasma is generated from the gas directly below the shower plate 26. The substrate W on the substrate support part 12 is processed by the chemical species from the generated plasma. Further, the electromagnetic wave also propagates downward (i.e., downstream) along the side wall 10a of the chamber 10, but the propagation of the electromagnetic wave downward (i.e., downstream) from the choke structure 16 is suppressed.

[0054] In the plasma processing apparatus 1 described above, with respect to the first part 161, the second part 162 is expanded along the direction of the electric field of the electromagnetic wave. Therefore, the intensity of the electric field in the second part 162 becomes small. Thus, according to the plasma processing apparatus 1, it is possible to suppress the discharge in the choke structure 16. For example, even if a gap is generated between the wall of the chamber 10 and the dielectric part 162d due to the difference in the coefficient of thermal expansion between the wall of the chamber 10 and the dielectric part 162d, the discharge in the choke structure 16 can be suppressed. Further, by configuring the choke structure 16 to satisfy the relationship of H1 < H2, the sum of the length W1 and the length W2 can be made shorter than about 1 / 4 of the wavelength of the electromagnetic wave in the choke structure 16, so that miniaturization of the choke structure 16 can be realized.

[0055] Hereinafter, with reference to FIG. 3, a plasma processing apparatus according to another exemplary embodiment will be described. FIG. 3 is a diagram schematically showing a plasma processing apparatus according to another exemplary embodiment. Hereinafter, the plasma processing apparatus 1B will be described from the viewpoint of the difference between the plasma processing apparatus 1B shown in FIG. 3 and the plasma processing apparatus 1.

[0056] The plasma processing apparatus 1B includes a choke structure 16B. The choke structure 16B is configured to suppress the propagation of electromagnetic waves downstream along the inner wall surface of the chamber 10 from the location where it is provided. The choke structure 16B is provided on the side wall 10a of the chamber 10. The side wall 10a includes an annular exhaust duct 40. The annular exhaust duct 40 provides an annular exhaust passage 40p therein. The annular exhaust duct 40 and the annular exhaust passage 40p have an annular shape and extend in the circumferential direction with respect to the axis AX. The inner peripheral wall of the annular exhaust duct 40 provides a plurality of through holes 40t. The plurality of through holes 40t are arranged along the circumferential direction with respect to the axis AX. The annular exhaust passage 40p communicates with the substrate processing space 10s through the plurality of through holes 40t.

[0057] The choke structure 16B includes a first portion 161B and a second portion 162B. The first portion 161B is connected to the substrate processing space 10s in the chamber 10. The first portion 161B provides a slit. The slit of the first portion 161B is formed on the inner peripheral wall of the annular exhaust duct 40. The first portion 161B and its slit have an annular shape and extend in the circumferential direction with respect to the axis AX. The second portion 162B extends from the first portion 161B within the wall of the chamber 10. In the plasma processing apparatus 1B, the second portion 162B is the annular exhaust passage 40p.

[0058] The length of the second portion 162B along the direction of the electric field of the electromagnetic wave in the second portion 162B may be longer than the length of the first portion 161B along the direction of the electric field of the electromagnetic wave in the first portion 161B. In each of the first portion 161B and the second portion 162B, the direction of the electric field of the electromagnetic wave is a direction orthogonal to the propagation direction of the electromagnetic wave and is the vertical direction. The propagation direction of the electromagnetic wave in each of the first portion 161B and the second portion 162B is a radial direction with respect to the axis AX and is the same direction.

[0059] The length of the second portion 162B along the propagation direction of the electromagnetic wave in the second portion 162B may be longer than the length of the first portion 161B along the propagation direction of the electromagnetic wave in the first portion 161B. Also in the plasma processing apparatus 1B, the sum of the length of the first portion 161B and the length of the second portion 162B along the propagation direction of the electromagnetic wave is set so as to cancel out the electromagnetic wave propagating along the inner wall surface of the chamber 10 by the reflected wave returned from the choke structure 16B. The sum of the length of the first portion 161B and the length of the second portion 162B along the propagation direction of the electromagnetic wave can be set to, for example, about 1 / 4 of the wavelength of the electromagnetic wave in the choke structure 16B.

[0060] The choke structure 16B further includes a dielectric portion 16d. The dielectric portion 16d is formed of a dielectric such as quartz, aluminum oxide, yttria, silicon carbide, or aluminum nitride. The dielectric portion 16d is provided at least in the slit of the first portion 161B. The slit of the first portion 161B is filled with the dielectric portion 16d. The dielectric portion 16d has an annular shape and extends in the circumferential direction with respect to the axis AX. The dielectric portion 16d extends into the annular exhaust passage 40p. That is, the dielectric portion 16d protrudes from the slit of the first portion 161B into the annular exhaust passage 40p.

[0061] The choke structure 16B may further include an insulating member 16i. Hereinafter, with reference to FIG. 3, FIGS. 4 and 5 will be referred to. FIG. 4 is a perspective view showing a broken example of an insulating member that can be adopted in the plasma processing apparatus shown in FIG. 3. FIG. 5 is a perspective view showing a broken another example of an insulating member that can be adopted in the plasma processing apparatus shown in FIG. 3.

[0062] The insulating member 16i is formed of an insulator such as quartz, aluminum oxide, yttria, silicon carbide, aluminum nitride, or polytetrafluoroethylene. The insulating member 16i is provided so as to at least partially cover the dielectric portion 16d in the annular exhaust passage 40p. In the plasma processing apparatus 1B, the intensity of the electric field of the electromagnetic wave in the annular exhaust passage 40p is reduced by the insulating member 16i.

[0063] In the examples shown in FIGS. 3 and 4, the insulating member 16i covers a portion of the dielectric part 16d in the annular exhaust passage 40p excluding the end portion. In the examples shown in FIGS. 3 and 4, the insulating member 16i includes a plurality of portions separated from each other. Each of the plurality of portions of the insulating member 16i is fixed to the inner peripheral wall of the annular exhaust duct 40, for example, using screws. Each of the plurality of portions of the insulating member 16i forms a substantially triangular shape in any cross section including the axis AX. That is, the length in the height direction of each of the plurality of portions of the insulating member 16i becomes smaller as the distance from the axis AX increases.

[0064] The plurality of portions of the insulating member 16i constitute a plurality of pairs. The two portions included in each of the plurality of pairs are arranged along the vertical direction and sandwich the dielectric part 16d therebetween. The plurality of pairs of the insulating member 16i are arranged along the circumferential direction. According to this example, since the plurality of portions of the insulating member 16i are separated from each other along the circumferential direction, even when the temperatures of the insulating member 16i and the annular exhaust duct 40 increase, the generation of a gap between the insulating member 16i and the inner peripheral wall of the annular exhaust duct 40 is suppressed, and abnormal discharge occurring in this gap can be suppressed.

[0065] In the example shown in FIG. 5, the insulating member 16i covers the entire dielectric part 16d in the annular exhaust passage 40p. In the example shown in FIG. 5, the insulating member 16i has elasticity. The insulating member 16i is formed of an elastic body such as fluororubber or silicone rubber, for example. In the example shown in FIG. 5, the insulating member 16i forms a substantially semicircular shape in any cross section including the axis AX. In the example shown in FIG. 5, the insulating member 16i may be a single member. Also in this example, even when the temperatures of the insulating member 16i and the annular exhaust duct 40 increase, the generation of a gap between the insulating member 16i and the inner peripheral wall of the annular exhaust duct 40 is suppressed, and abnormal discharge occurring in this gap can be suppressed.

[0066] As shown in FIG. 3, the outer peripheral wall 40e of the annular exhaust duct 40 provides an opening 40o. Another exhaust duct 42 is connected to the annular exhaust duct 40. The exhaust duct 42 provides an exhaust passage 42p. The exhaust duct 42 and the exhaust passage 42p extend in a direction away from the chamber 10, for example, in a radial direction with respect to the axis AX. The exhaust passage 42p is connected to the annular exhaust passage 40p via the opening 40o. Further, an exhaust device is connected to the exhaust duct 42. The exhaust device may include a vacuum pump such as a dry pump and / or a turbo molecular pump and an automatic pressure control valve.

[0067] A short - circuit portion 40c is provided in the opening 40o. The short - circuit portion 40c is formed of a conductor such as aluminum and, for example, has a rod - like shape. The short - circuit portion 40c electrically connects a pair of edges defining the opening 40o, that is, the upper edge and the lower edge to each other. The short - circuit portion 40c separates the opening 40o into a plurality of portions. The length along the circumferential direction of each of the plurality of portions of the opening 40o can be set to a length that is 1 / 10 or less of the wavelength of the electromagnetic wave in the annular exhaust passage 40p. Due to the short - circuit portion 40c, the outer peripheral wall 40e functions as a short - circuit surface for electromagnetic waves even in the portion where the opening 40o is provided.

[0068] Hereinafter, with reference to FIG. 6, a plasma processing apparatus according to another exemplary embodiment will be described. FIG. 6 is a diagram schematically showing a plasma processing apparatus according to still another exemplary embodiment. Hereinafter, the plasma processing apparatus 1C will be described from the viewpoint of the differences between the plasma processing apparatus 1C shown in FIG. 6 and the plasma processing apparatus 1.

[0069] The plasma processing apparatus 1C includes a choke structure 16C. The choke structure 16C is configured to suppress the downstream propagation of electromagnetic waves along the inner wall surface of the chamber 10 from the location where it is provided.

[0070] The choke structure 16C includes a slit-shaped first portion 161C and a second portion 162C. The first portion 161C is connected to the substrate processing space 10s in the chamber 10. The second portion 162C extends from the first portion 161C within the wall of the chamber 10. The second portion 162C may provide a cavity that extends from the first portion 161C within the wall of the chamber 10.

[0071] The first portion 161C includes a dielectric part 161d provided therein, i.e., within the slit. The slit of the first portion 161C is filled with the dielectric part 161d. The dielectric part 161d is formed of a dielectric such as quartz, aluminum oxide, yttria, silicon carbide, or aluminum nitride.

[0072] In one embodiment, the choke structure 16C is provided on the side wall 10a of the chamber 10. Further, the choke structure 16C is provided below the introduction part 14. The first portion 161C and its slit have an annular shape and extend circumferentially with respect to the central axis of the side wall 10a, i.e., the axis AX. Also, the second portion 162C and its cavity have an annular shape and extend circumferentially with respect to the axis AX. The second portion 162C extends radially outward with respect to the first portion 161C. Also, the dielectric part 161d has an annular shape and extends circumferentially with respect to the axis AX. In the plasma processing apparatus 1C, the propagation direction of the electromagnetic wave in the first portion 161C is in the radial direction with respect to the axis AX, and the propagation direction of the electromagnetic wave in the second portion 162C is in a direction parallel to the axis AX. The sum of the length of the first portion 161C in the propagation direction of the electromagnetic wave and the length of the second portion 162C in the propagation direction of the electromagnetic wave can be set, for example, to about 1 / 4 of the wavelength of the electromagnetic wave within the choke structure 16C.

[0073] The pressure inside the second part 162C (inside its cavity) is set to a pressure higher than the pressure in the substrate processing space 10s. In one embodiment, the side wall 10a of the chamber 10 may provide a passage 10p. The passage 10p may communicate the cavity of the second part 162C with the atmospheric space outside the chamber 10. In this case, since the pressure in the cavity of the second part 162C becomes atmospheric pressure, the discharge in the second part 162C can be suppressed. Alternatively, a gas supply unit 50 may be connected to the passage 10p. The gas supply unit 50 is configured to supply gas to the cavity of the second part 162C. The gas supplied by the gas supply unit 50 to the cavity of the second part 162C may be a fluorine-containing gas. Also in this case, the discharge in the second part 162C can be suppressed.

[0074] Hereinafter, with reference to FIG. 7, a plasma processing apparatus according to still another exemplary embodiment will be described. FIG. 7 is a diagram schematically showing a plasma processing apparatus according to still another exemplary embodiment. Hereinafter, the plasma processing apparatus 1D will be described from the viewpoint of the difference between the plasma processing apparatus 1D shown in FIG. 7 and the plasma processing apparatus 1B. Also, hereinafter, in addition to FIG. 7, FIGS. 8 and 9 will be referred to. FIG. 8 is a perspective view showing a broken view of an example of a dielectric part, an insulating member, and an elastic ring that can be adopted in the plasma processing apparatus shown in FIG. 7. FIG. 9 is a perspective view showing a broken view of an example of an insulating member that can be adopted in the plasma processing apparatus shown in FIG. 7.

[0075] The plasma processing apparatus 1D includes a choke structure 16D. The choke structure 16D includes a first part 161B and a second part 162B, similar to the choke structure 16B. The plasma processing apparatus 1D includes a dielectric part 60, an insulating member 61, and at least one elastic ring 62 instead of the dielectric part 16d and the insulating member 16i. Other configurations of the plasma processing apparatus 1D are the same as other configurations of the plasma processing apparatus 1B.

[0076] The dielectric part 60 includes a plurality of first members 601 and a plurality of second members 602. The plurality of first members 601 and the plurality of second members 602 are alternately arranged along the circumferential direction within the first portion 161B (its slit). That is, the dielectric part 60 is divided in the circumferential direction. A slight gap may be interposed between each of the plurality of first members 601 and the second member 602 arranged adjacent thereto. The dielectric part 60 protrudes from the slit of the first portion 161B into the annular exhaust passage 40p. The dielectric part 60, that is, the plurality of first members 601 and the plurality of second members 602, is formed of an insulator such as quartz, alumina, yttria, silicon carbide, aluminum nitride, polytetrafluoroethylene, or the like.

[0077] The plurality of first members 601 are fitted into the first portion 161B (its slit). That is, each of the plurality of first members 601 has a thickness substantially the same as the length in the vertical direction of the first portion 161B (its slit). Each of the plurality of first members 601 is clamped in the vertical direction by the inner peripheral wall defining the first portion 161B (its slit).

[0078] The thickness of each of the plurality of second members 602 is smaller than the thickness of each of the plurality of first members 601. The thickness of each of the plurality of second members 602 is smaller than the length in the vertical direction of the first portion 161B (its slit). The length in the vertical direction of the gap between each of the plurality of second members 602 and the inner peripheral wall defining the first portion 161B (its slit) is a length such that plasma does not penetrate, for example, a length equal to or less than the sheath thickness. Each of the plurality of second members 602 is movable within the first portion 161B (its slit).

[0079] The insulating member 61 is formed of an insulator such as polytetrafluoroethylene. The insulating member 61 has an annular shape and extends in the circumferential direction within the annular exhaust passage 40p. The insulating member 61 covers the dielectric part 60 within the annular exhaust passage 40p. Specifically, the insulating member 61 provides a groove 61g on its inner peripheral side. Within the annular exhaust passage 40p, the dielectric part 60 is disposed within the groove 61g. In the plasma processing apparatus 1D, the intensity of the electric field of the electromagnetic wave within the annular exhaust passage 40p is reduced by the insulating member 61.

[0080] The insulating member 61 provides a first cut portion 611 and a second cut portion 612. The first cut portion 611 extends from the inner peripheral side to the outer peripheral side of the insulating member 61. The second cut portion 612 extends from the outer peripheral side to the inner peripheral side of the insulating member 61. The first cut portion 611 and the second cut portion 612 are provided within an angular range of 90 degrees or less with respect to the center of the insulating member 61. That is, the first cut portion 611 and the second cut portion 612 are provided in the circumferential direction in the vicinity of each other and form a pair. The portion between the first cut portion 611 and the second cut portion 612 in this pair is easily deformable.

[0081] In one embodiment, the insulating member 61 may provide a plurality of pairs of cut portions 61p each including a first cut portion 611 and a second cut portion 612. The plurality of pairs of cut portions 61p are arranged along the circumferential direction. The circumferential interval between the first cut portion 611 and the second cut portion 612 in each of the plurality of pairs of cut portions 61p is narrower than the circumferential interval of the plurality of pairs of cut portions 61p. The insulating member 61 is easily deformable in the portion between the first cut portion 611 and the second cut portion 612 in each of the plurality of pairs of cut portions 61p.

[0082] In one embodiment, the plasma processing apparatus 1D may include two elastic rings 62 as at least one elastic ring 62. Each of the two elastic rings 62 is, for example, an O-ring. The two elastic rings 62 extend in the circumferential direction within the annular exhaust passage 40p and are arranged along the vertical direction. The two elastic rings 62 press the insulating member 61 against the inner peripheral wall where the first portion 161B is formed. As a result, the inner peripheral surface of the insulating member 61 is in close contact with the inner peripheral wall where the first portion 161B is formed.

[0083] In the plasma processing apparatus 1D, the dielectric part 60 is divided in the circumferential direction and a plurality of second portions 162 are movable. Therefore, even if the temperature changes in the chamber 10, no stress is applied to the dielectric part 60, and cracking of the dielectric part 60 is prevented. Further, since the insulating member 61 is stretchable in the circumferential direction, even if the temperature changes in the chamber 10, generation of a gap between the insulating member 61 and the inner peripheral wall is suppressed.

[0084] Hereinafter, with reference to FIGS. 10 and 11, a plasma processing apparatus according to still another exemplary embodiment will be described. FIG. 10 is a diagram schematically showing a plasma processing apparatus according to still another exemplary embodiment. FIG. 11 is a diagram showing an enlarged part of a plasma processing apparatus according to still another exemplary embodiment. Hereinafter, the plasma processing apparatus 1E will be described from the viewpoint of the difference between the plasma processing apparatus 1E shown in FIGS. 10 and 11 and the plasma processing apparatus 1B.

[0085] The plasma processing apparatus 1E includes a choke structure 16E. The choke structure 16E includes a first portion 161B and a second portion 162B, similar to the choke structure 16B. The plasma processing apparatus 1E includes a dielectric part 16Ed instead of the dielectric part 16d and the insulating member 16i.

[0086] The dielectric part 16Ed is formed of a dielectric such as quartz, aluminum oxide, yttria, silicon carbide, or aluminum nitride. The dielectric part 16Ed has a substantially annular shape. A part of the dielectric part 16Ed, that is, the inner edge side portion, is provided in the slit of the first part 161B. The dielectric part 16Ed extends into the annular exhaust passage 40p. The shape of an arbitrary cross section including the axis AX of the dielectric part 16Ed in the annular exhaust passage 40p forms a substantially triangle. That is, in the annular exhaust passage 40p, the length in the height direction of the dielectric part 16Ed becomes smaller as the distance from the axis AX increases.

[0087] In the plasma processing apparatus 1E, the side wall of the chamber 10 includes a first wall member 401 and a second wall member 402. The first wall member 401 has a substantially annular shape and extends in the circumferential direction above the first part 161B. The second wall member 402 is separable from the first wall member 401. The second wall member 402 has a substantially annular shape and extends in the circumferential direction below the first part 161B. The first wall member 401 and the second wall member 402 define the slit of the first part 161B therebetween. The first wall member 401 and the second wall member 402 elastically sandwich the dielectric part 16Ed disposed therebetween, that is, in the slit of the first part 161B.

[0088] In one embodiment, the side wall of the chamber 10 may further include a third wall member 403 and a fourth wall member 404. The third wall member 403 is separable from the first wall member 401 and the second wall member 402 and constitutes the annular exhaust duct 40 together with the first wall member 401 and the second wall member 402. The third wall member 403 has a substantially annular shape. The fourth wall member 404 extends below the annular exhaust duct 40. Note that the first wall member 401, the second wall member 402, the third wall member 403, and the fourth wall member 404 are formed of a metal such as aluminum and are grounded.

[0089] The first wall member 401 is provided on the second wall member 402 and the third wall member 403. The first wall member 401 defines the annular exhaust passage 40p from above. The second wall member 402 extends radially inward with respect to the third wall member 403, and together with the third wall member 403, defines the annular exhaust passage 40p from below. In the plasma processing apparatus 1E, a plurality of through holes 40t that communicate the annular exhaust passage 40p and the substrate processing space 10s with each other are formed in the bottom wall of the annular exhaust duct 40. Specifically, the plurality of through holes 40t are formed in the bottom wall portion of the second wall member 402. In the plasma processing apparatus 1E, the plurality of through holes 40t are arranged along the circumferential direction. Note that, similar to the plasma processing apparatus 1B, the plurality of through holes 40t may be formed in the inner peripheral wall of the annular exhaust duct 40. The plurality of through holes 40t may have a width (or diameter) of a size corresponding to the distance from the connection position between the exhaust passage 42p and the annular exhaust passage 40p. In this case, the uniformity of exhaust in the circumferential direction is improved.

[0090] The plasma processing apparatus 1E may further include a spiral spring gasket 71 and an O-ring 72. The outer edge portion of the second wall member 402 extends above the inner edge portion of the third wall member 403, and the spiral spring gasket 71 is sandwiched between the outer edge portion of the second wall member 402 and the inner edge portion of the third wall member 403. The spiral spring gasket 71 is partially disposed in a groove formed in the inner edge portion of the third wall member 403. The spiral spring gasket 71 contracts in the height direction between the outer edge portion of the second wall member 402 and the inner edge portion of the third wall member 403 when the fourth wall member 404 abuts against the third wall member 403 from below. The second wall member 402 presses the dielectric part 16Ed upward by the reaction force generated by the spiral spring gasket 71. As a result, the dielectric part 16Ed disposed in the slit of the first part 161B is elastically sandwiched between the first wall member 401 and the second wall member 402. Note that the depth of the groove formed in the inner edge portion of the third wall member 403 is set so that the dielectric part 16Ed is not damaged by the reaction force generated by the spiral spring gasket 71.

[0091] The O-ring 72 is sandwiched between the second wall member 402 and the fourth wall member 404. The O-ring 72 is partially disposed in a groove formed in the second wall member 402. The O-ring 72 contracts in the height direction by being sandwiched between the second wall member 402 and the fourth wall member 404. The second wall member 402 presses the dielectric part 16Ed upward by the reaction force generated by the O-ring 72. As a result, the dielectric part 16Ed disposed in the slit of the first part 161B is elastically sandwiched between the first wall member 401 and the second wall member 402. Note that the depth of the groove formed in the second wall member 402 is set so that the dielectric part 16Ed is not damaged by the reaction force generated by the O-ring 72.

[0092] As shown in FIG. 11, in one embodiment, the plasma processing apparatus 1E may further include an ignition monitor 74. The ignition monitor 74 is configured to monitor the ignition of plasma in the annular exhaust passage 40p. The ignition monitor 74 may include, for example, an optical sensor that monitors the emission of plasma. When the ignition monitor 74 detects the ignition of plasma in the annular exhaust passage 40p, the plasma processing apparatus 1E may stop the generation of high-frequency power by the high-frequency power supply 30.

[0093] Hereinafter, refer to FIGS. 12 and 13. FIG. 12 is a diagram showing a part of a dielectric part and an annular exhaust duct in a plasma processing apparatus according to still another exemplary embodiment. Each of FIGS. 13(a) and 13(b) is a partially enlarged view of a dielectric part and an annular exhaust duct in a plasma processing apparatus according to still another exemplary embodiment. Note that FIG. 13(a) shows the cross-sectional shape of the dielectric part in a cross-section orthogonal to the axis AX, and FIG. 13(b) shows the cross-sectional shape of the dielectric part and the cross-sectional shape of the wall member of the annular exhaust passage in a cross-section including the axis AX.

[0094] In one embodiment, the annular exhaust duct 40 of the plasma processing apparatus 1E may be provided with three recesses 40r. The three recesses 40r extend radially inward from the inner peripheral surface 40i of the annular exhaust duct 40 that defines the annular exhaust passage 40p, and are arranged at equal intervals along the circumferential direction. In one embodiment, the three recesses 40r may be defined between a first wall member 401 and a second wall member 402. Note that the annular exhaust duct 40 of the plasma processing apparatus 1E may be provided with three or more recesses 40r.

[0095] Further, the dielectric part 16Ed may further include three protrusions 16p. The three protrusions 16p are respectively arranged in the three recesses 40r. The three protrusions 16p may have a U-shaped planar shape. Note that the dielectric part 16Ed may be provided with three or more protrusions 16p within the range of the number of recesses 40r.

[0096] According to the plasma processing apparatus 1E, the dielectric part 16Ed is elastically clamped within the first portion 161B. Therefore, even if the side wall of the chamber 10 and the wall members constituting the annular exhaust duct 40 are deformed due to thermal expansion or the like, damage to the dielectric part 16Ed is suppressed. Further, the occurrence of a gap between the dielectric part 16Ed and the wall members constituting the annular exhaust duct 40 is suppressed.

[0097] Further, according to the plasma processing apparatus 1E, due to the above-described three protrusions 16p and three recesses 40r, even if the side wall of the chamber 10 and the wall members constituting the annular exhaust duct 40 are deformed due to thermal expansion or the like, changes in the position of the dielectric part 16Ed in the radial direction and the circumferential direction are suppressed. Therefore, the concentricity between the dielectric part 16Ed and the annular exhaust duct 40 is maintained.

[0098] Note that the plasma processing apparatus 1E may include, instead of the dielectric part 16Ed, the dielectric part 16d and the insulating member 16i shown in FIG. 4 or FIG. 5, or the dielectric part 60, the insulating member 61, and at least one elastic ring 62 shown in FIG. 8.

[0099] Although various exemplary embodiments have been described above, various additions, omissions, substitutions, and changes may be made without being limited to the above-described exemplary embodiments. Also, it is possible to form other embodiments by combining elements in different embodiments.

[0100] For example, the choke structure according to various embodiments may be provided at any location on the wall of the chamber 10 as long as it can suppress the propagation of electromagnetic waves to unnecessary locations in the chamber 10.

[0101] From the above description, it will be understood that the various embodiments of the present disclosure are described herein for purposes of illustration and that various changes can be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, and the true scope and spirit are indicated by the appended claims.

Description of Reference Numerals

[0102] 1... Plasma processing apparatus, 10... Chamber, 12... Substrate support portion, 14... Introduction portion, 16... Choke structure, 18... Waveguide portion, 30... High-frequency power source.

Claims

1. A chamber, an introduction part provided so that electromagnetic waves are introduced into the chamber therefrom, a choke structure provided on the wall of the chamber and configured to suppress the propagation of electromagnetic waves downstream along the inner wall surface of the chamber from the location where it is provided, comprising: the choke structure has a slit-shaped first part connected to the space inside the chamber, and a second part extending from the first part in the wall of the chamber, including: the length of the second part along the direction of the electric field of the electromagnetic wave in the second part is longer than the length of the first part along the direction of the electric field of the electromagnetic wave in the first part, a plasma processing apparatus.

2. The length of the second part along the propagation direction of the electromagnetic wave in the second part is longer than the length of the first part along the propagation direction of the electromagnetic wave in the first part, the plasma processing apparatus according to claim 1.

3. The propagation direction of the electromagnetic wave in the first part and the propagation direction of the electromagnetic wave in the second part are the same, the plasma processing apparatus according to claim 1 or 2.

4. The choke structure further includes a dielectric part provided in the first part, the plasma processing apparatus according to any one of claims 1 to 3.

5. The choke structure further includes a dielectric part provided in the second part, the plasma processing apparatus according to claim 4.

6. The wall of the chamber is a side wall of the chamber, the side wall includes an annular exhaust duct that extends in the circumferential direction with respect to the central axis of the side wall and communicates with the space inside the chamber, the first part is formed on the wall that defines the annular exhaust duct and extends in the circumferential direction with respect to the central axis, the second part is the annular exhaust passage, the plasma processing apparatus according to claim 4.

7. The side wall of the chamber includes a first wall member extending above the first part and a second wall member separable from the first wall member and extending below the first part, the first wall member and the second wall member elastically sandwich the dielectric part disposed therebetween, the plasma processing apparatus according to claim 6.

8. The side wall of the chamber further includes a third wall member that is separable from the first wall member and the second wall member and forms the annular exhaust duct together with the first wall member and the second wall member, and a fourth wall member that extends below the annular exhaust duct. The first wall member is provided on the second wall member and the third wall member, and defines the annular exhaust passage from above. The second wall member extends inside the third wall member, and together with the third wall member, defines the annular exhaust passage from below. The second wall member presses the dielectric part by the reaction force from the O-ring and / or the spiral spring gasket. The plasma processing apparatus according to claim 7.

9. The annular exhaust duct provides three or more recesses that extend radially inward from its inner circumferential surface defining the annular exhaust passage and are arranged at equal intervals along the circumferential direction. The dielectric part includes three or more convex parts arranged in the three or more recesses. The plasma processing apparatus according to claim 7 or 8.

10. The plasma processing apparatus according to any one of claims 6 to 9, wherein the dielectric part extends into the annular exhaust passage.

11. The dielectric part extends into the annular exhaust passage. The dielectric part includes a plurality of first members and a plurality of second members. The plurality of first members and the plurality of second members are alternately arranged along the circumferential direction in the first part. The plurality of first members are fitted to the first part. The thickness of each of the plurality of second members is smaller than the thickness of each of the plurality of first members. The plasma processing apparatus according to claim 6.

12. The plasma processing apparatus according to claim 10 or 11, wherein the choke structure further includes an insulating member provided to at least partially cover the dielectric part in the annular exhaust passage.

13. The plasma processing apparatus according to claim 12, wherein the insulating member covers a portion of the dielectric part in the annular exhaust passage except for the end portion of the dielectric part or the entire dielectric part.

14. The plasma processing apparatus according to claim 12 or 13, wherein the insulating member includes a plurality of portions separated from each other in the circumferential direction.

15. The insulating member has an annular shape, and provides a first cut portion extending from the inner peripheral side to the outer peripheral side of the insulating member and a second cut portion extending from the outer peripheral side to the inner peripheral side of the insulating member. The plasma processing apparatus according to claim 12 or 13.

16. The first cut portion and the second cut portion are provided within an angular range of 90 degrees or less with respect to the center of the insulating member. The plasma processing apparatus according to claim 15.

17. The insulating member provides a plurality of pairs of cut portions each including the first cut portion and the second cut portion, The plurality of pairs of cut portions are arranged along the circumferential direction, The circumferential interval between the first cut portion and the second cut portion in each of the plurality of pairs of cut portions is narrower than the circumferential interval of the plurality of pairs of cut portions in the circumferential direction. The plasma processing apparatus according to claim 15 or 16.

18. The plasma processing apparatus according to any one of claims 12 to 17, further comprising an elastic ring that presses the insulating member against the wall in which the first portion is formed.

19. The insulating member has elasticity. The plasma processing apparatus according to any one of claims 12 to 18.

20. The annular exhaust duct includes an outer peripheral wall that provides an opening, Another exhaust duct is connected to the annular exhaust duct such that its exhaust path is connected to the annular exhaust path through the opening, A short circuit portion that electrically connects a pair of edges defining the opening to each other is provided within the opening. The plasma processing apparatus according to any one of claims 6 to 19.

21. The second portion is a cavity, and the pressure in the second portion is set to a pressure higher than the pressure in the space in the chamber. The plasma processing apparatus according to claim 4.

22. A chamber, An introduction portion provided so that electromagnetic waves are introduced into the chamber therefrom, A choke structure provided on the wall of the chamber and configured to suppress the downstream propagation of electromagnetic waves along the inner wall surface of the chamber from the location where it is provided, Comprising, The choke structure is, A slit-shaped first portion connected to the space in the chamber, A dielectric portion provided in the first portion, A second portion extending from the first portion in the wall of the chamber, Including, The second part is a cavity, and the pressure in the second part is set to a pressure higher than the pressure in the space in the chamber. Plasma processing apparatus.

23. The plasma processing apparatus according to claim 21 or 22, wherein the choke structure provides a passage for communicating the second part with the atmospheric space outside the chamber.

24. The plasma processing apparatus according to any one of claims 21 to 23, further comprising a gas supply unit configured to supply gas to the second part.

25. The plasma processing apparatus according to claim 24, wherein the gas is a fluorine-containing gas.

26. The wall of the chamber is a side wall of the chamber. The first part and the second part extend in the circumferential direction with respect to the central axis of the side wall. The plasma processing apparatus according to any one of claims 1 to 5 and claims 21 to 25.

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