Plasma processing equipment

Abstract

This invention provides a technology for equalizing the intensity of electromagnetic waves emitted from multiple slots in the resonator of a plasma processing device. [Solution] The disclosed plasma processing apparatus includes a chamber, an emission section, and a waveguide section. The emission section extends circumferentially around the central axis of the plasma generation space to radiate electromagnetic waves into the chamber. The waveguide section supplies electromagnetic waves to the emission section. The waveguide section includes a resonator. The first and second ends of the waveguide of the resonator extend circumferentially around the central axis. A plurality of slots are arranged along the second end and are arranged circumferentially around the central axis above the emission section, electromagnetically coupling the waveguide and the emission section to each other. The effective circumferential length of each of the plurality of slots is set to be shorter as the circumferential distance of the circumferential center of each of the plurality of slots with respect to a reference plane extending radially from the central axis through the electromagnetic wave inlet of the resonator parallel to the central axis is longer.

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 the processing of substrates. As one type of plasma processing apparatus, there is known one that excites a gas using high-frequency waves that are 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 container, a stage, an upper electrode, an introduction part, and a waveguide part. The stage is provided inside the processing container. The upper electrode is provided above the stage via the space inside the processing container. The introduction part is a high-frequency introduction part. The introduction part is provided at a lateral end of the space and extends in the circumferential direction around the central axis of the processing container. The waveguide part is configured to supply high-frequency waves to the introduction part. The waveguide part includes a resonator that provides a waveguide. The waveguide of the resonator extends in the circumferential direction around the central axis, extends in the direction in which the central axis extends, and is connected to the introduction part.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] [[ID=3a4]] The present disclosure provides a technique for equalizing the intensity of electromagnetic waves emitted from a plurality of slots of a resonator 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 emission section, and a waveguide section. The chamber includes a plasma generation space. The emission section extends circumferentially around the central axis of the chamber and plasma generation space and is provided for radiating electromagnetic waves into the plasma generation space. The waveguide section is configured to supply electromagnetic waves to the emission section. The waveguide section includes a resonator having a waveguide. The resonator has a coupling section, a first end, a second end, and a plurality of slots. The coupling section is an electromagnetic wave inlet radially away from the central axis. The first end constitutes one end of the waveguide of the resonator and extends circumferentially around the central axis. The second end constitutes the other end of the waveguide of the resonator and extends circumferentially around the central axis. The plurality of slots are arranged along the second end and are arranged circumferentially around the central axis above the emission section, electromagnetically coupling the waveguide and the emission section to each other. The effective circumferential length of each of the multiple slots is set such that the longer the circumferential distance between the circumferential center of each of the multiple slots and a reference plane extending radially from the central axis through the joint parallel to the central axis, the shorter the effective circumferential length of each of the multiple slots. [Effects of the Invention]

[0006] According to one exemplary embodiment, it is possible to equalize the intensity of electromagnetic waves emitted from multiple slots in the resonator of a plasma processing apparatus. [Brief explanation of the drawing]

[0007] [Figure 1] This figure shows a plasma processing apparatus according to one exemplary embodiment. [Figure 2] This is a cross-sectional view taken along line II-II in Figure 1. [Figure 3] Figure 3(a) shows the simulation results of the circumferential electric field strength distribution in one example of a plasma processing apparatus, and Figure 3(b) shows the simulation results of the circumferential electric field strength distribution in a comparative example of a plasma processing apparatus. [Figure 4]This is a horizontal cross-sectional view showing another example of a resonator that may be used in the plasma processing apparatus shown in Figure 1. [Figure 5] This figure shows a plasma processing apparatus according to yet another exemplary embodiment. [Figure 6] This is a cross-sectional view taken along the line VI-VI in Figure 5. [Figure 7] Figure 7(a) shows the simulation results of the circumferential electric field strength distribution in a plasma processing apparatus of another example, and Figure 7(b) shows the simulation results of the circumferential electric field strength distribution in a plasma processing apparatus of another comparative example. [Figure 8] Figure 5 is a horizontal cross-sectional view showing another example of a resonator that may be used in the plasma processing apparatus shown. [Modes for carrying out the invention]

[0008] Various exemplary embodiments will be described in detail below with reference to the drawings. In each drawing, the same or corresponding parts will be denoted by the same reference numerals.

[0009] Figure 1 shows a plasma processing apparatus according to one exemplary embodiment. Figure 2 is a cross-sectional view taken along line II-II in Figure 1. The plasma processing apparatus 1 shown in Figure 1 includes a chamber 10, an emission unit 16, and a waveguide unit 18. The plasma processing apparatus 1 may further include a substrate support unit 12 and a high-frequency power supply 24.

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

[0011] The bottom of the chamber 10 provides an exhaust port 10e. An exhaust system is connected to the exhaust port 10e. The exhaust system 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 portion 12 is located within the processing space 10s. The substrate support portion 12 is configured to support the substrate W placed on its upper surface in a substantially horizontal position. The substrate support portion 12 has a substantially disc shape. The central axis of the substrate support portion 12 is axis AX.

[0013] The emission section 16 is provided to radiate electromagnetic waves into the plasma generation space. The emission section 16 is formed from a dielectric material such as quartz, aluminum nitride, or aluminum oxide. The emission section 16 extends circumferentially around the axis AX. The emission section 16 may have an annular shape.

[0014] In one embodiment, the plasma generation space extends within the processing space 10s and directly below the excitation electrode. In one embodiment, the excitation electrode includes a shower plate 22, and the plasma generation space is directly below the shower plate 22.

[0015] The shower plate 22 may be formed of a metal such as aluminum. The shower plate 22 provides a plurality of gas holes 22h. The plurality of gas holes 22h extend in the thickness direction (vertical direction) of the shower plate 22 and penetrate the shower plate 22. The discharge part 16 extends so as to surround the central part of the shower plate 22 having the plurality of gas holes 22h. The discharge part 16 and the shower plate 22 are arranged so as to close the opening at the upper end of the chamber 10.

[0016] The shower plate 22 is provided under the resonator 20 of the waveguide part 18. The shower plate 22 extends over the plasma generation space. The shower plate 22 and the bottom plate 20bp of the resonator 20 define a gas diffusion space 14d therebetween. The central axis of the gas diffusion space 14d may be the axis AX. A plurality of gas holes 22h of the shower plate 22 are connected to the gas diffusion space 14d. Further, the resonator 20 provides an inlet 14h. The inlet 14h may extend on the axis AX. The inlet 14h is connected to the gas diffusion space 14d. A gas supply part 26 is connected to the gas diffusion space 14d. The gas output from the gas supply part 26 is supplied to the plasma generation space through the inlet 14h, the gas diffusion space 14d, and the plurality of gas holes 22h.

[0017] In the plasma processing apparatus 1, the gas in the plasma generation space is excited by the electromagnetic wave emitted from the discharge part 16 into the plasma generation space, and plasma is generated. The electromagnetic wave emitted from the discharge part 16 into the plasma generation region may be a high frequency such as a VHF wave or a UHF wave.

[0018] The waveguide part 18 is configured to supply an electromagnetic wave to the discharge part 16. The waveguide part 18 includes a resonator 20. The resonator 20 may be provided above the chamber 10. The resonator 20 has a waveguide 20w.

[0019] The resonator 20 includes a coupling portion 20p. The coupling portion 20p is an entrance of electromagnetic waves to the waveguide 20w. The electromagnetic waves are generated based on the high-frequency power generated by the high-frequency power source 24. The high-frequency power source 24 may be configured to be able to change the frequency of the output high-frequency power. The high-frequency power source 24 is electrically connected to the coupling portion 20p. The high-frequency power source 24 and the coupling portion 20p may be electrically connected via a coaxial connector 25. The resonator 20 resonates the electromagnetic waves input to the coupling portion 20p within the waveguide 20w and propagates them toward the emission portion 16. The electromagnetic waves are emitted from the emission portion 16 into the plasma generation space.

[0020] The waveguide 20w of the resonator 20 may provide a cavity surrounded by walls. The walls of the waveguide 20w are formed of a material such as metal. The walls of the waveguide 20w may be formed of an aluminum alloy, copper, nickel, stainless steel, etc., and may be coated with a low-resistance material such as silver, gold, or rhodium.

[0021] The resonator 20 includes a first end 201 and a second end 202. The first end 201 and the second end 202 constitute one end and the other end of the waveguide 20w of the resonator 20. The waveguide 20w extends between the first end 201 and the second end 202. The first end 201 extends along the circumferential direction around the axis AX. The second end 202 also extends along the circumferential direction around the axis AX.

[0022] In one embodiment, the wall of the resonator 20 may include an inner peripheral portion 20i and an outer peripheral portion 20o. The inner peripheral portion 20i extends around the axis AX, which is its central axis, and has a substantially cylindrical shape. The outer peripheral portion 20o extends coaxially with the inner peripheral portion 20i around the axis AX and has a substantially cylindrical shape. The inner peripheral portion 20i and the outer peripheral portion 20o may be composed of a plate-like body having a cylindrical shape, or may be composed of a plurality of columnar bodies arranged along the circumferential direction.

[0023] The waveguide 20w may have a layered structure that folds back between the outer circumferential portion 20o and the inner circumferential portion 20i. In this case, the walls of the waveguide 20w may include, in addition to the inner circumferential portion 20i and the outer circumferential portion 20o, a plurality of walls that extend horizontally to form a layered structure.

[0024] Furthermore, the waveguide 20w may include an upper part 20a constituting the uppermost layer of the layered structure and a lower part 20b constituting the lowest layer of the layered structure. The upper part 20a may provide a first end 201, i.e., an upper end, at its outer periphery 20o. The lower part 20b may provide a second end 202, i.e., a lower end, at its outer periphery 20o.

[0025] The aforementioned coupling portion 20p may be provided on the upper part 20a. In this case, the inner conductor of the coaxial connector 25 is connected to the wall of the waveguide 20w that defines the upper part 20a from below, and the outer conductor of the coaxial connector 25 is connected to the wall (upper wall) of the waveguide 20w that defines the upper part 20a from above.

[0026] Furthermore, the resonator 20 includes a plurality of slots 20s. The plurality of slots 20s extend circumferentially with respect to the axis AX. The plurality of slots 20s are arranged circumferentially around the axis AX above the discharge section 16. The plurality of slots 20s may be arranged at equal intervals along the circumferential direction. The plurality of slots 20s may be arranged such that their centers in the circumferential direction are located at equal intervals along the circumferential direction.

[0027] As shown in Figure 2, the direction in which the joint portion 20p is positioned relative to the axis AX may coincide with the direction in which the portion between two adjacent slots 20s in the circumferential direction is positioned relative to the axis AX. Alternatively, the direction in which the joint portion 20p is positioned relative to the axis AX may coincide with the direction in which the circumferential center of one of the slots 20s is positioned relative to the axis AX. In either of these cases, the multiple slots 20s may be arranged symmetrically with respect to the longitudinal section containing the joint portion 20p and the axis AX.

[0028] Multiple slots 20s electromagnetically couple the waveguide 20w and the emission section 16 to each other. Multiple slots 20s may also be electromagnetically coupled to the emission section 16 via waveguide 18w. Waveguides 18w extend in a ring-like manner along the circumferential direction and are interposed between each of the multiple slots 20s and the emission section 16.

[0029] The effective circumferential length of each of the multiple slots 20s is set such that it becomes shorter as the circumferential distance between the circumferential center of each of the multiple slots 20s and the reference plane RP increases. The reference plane RP is a virtual plane that extends radially from the axis AX through the coupling portion 20p, parallel to the axis AX. The effective circumferential length of each of the multiple slots 20s is the circumferential length of the portion in each of the multiple slots 20s that effectively contributes to the emission of electromagnetic waves. In the example in Figure 2, the effective length of each of the multiple slots 20s is the circumferential distance between one end and the other in the circumferential direction. With such a plasma processing apparatus 1, it is possible to equalize the intensity of electromagnetic waves emitted from the multiple slots 20s of the resonator 20.

[0030] The following describes the simulation results of the circumferential electric field strength distribution related to the plasma processing apparatus 1. In the first simulation, the circumferential electric field strength distribution in the waveguide 18w was determined at a position 1 mm below each of the multiple slots 20s of the plasma processing apparatus 1 shown in Figures 1 and 2. In the second simulation, as a comparative example, the circumferential electric field strength distribution in the waveguide 18w was determined in the same manner as in the first simulation for a plasma processing apparatus identical to the plasma processing apparatus 1 shown in Figures 1 and 2, except that the effective circumferential lengths of each of the multiple slots 20s are the same.

[0031] Figure 3(a) shows the simulation results of the circumferential electric field strength distribution in an example plasma processing apparatus, and represents the results of the first simulation. Figure 3(b) shows the simulation results of the circumferential electric field strength distribution in a comparative example plasma processing apparatus, and represents the results of the second simulation. In both Figure 3(a) and Figure 3(b), the horizontal axis represents the circumferential angle within the waveguide 18w with reference to a plane extending symmetrically in the opposite direction to the reference plane RP with respect to the axis AX, and the vertical axis represents the electric field strength. As can be seen from Figure 3(a) and Figure 3(b), the variation in peak electric field strength in the electric field strength distribution obtained in the first simulation was smaller than the variation in peak electric field strength in the electric field strength distribution obtained in the second simulation. Therefore, it was confirmed that the plasma processing apparatus 1 makes it possible to equalize the intensity of electromagnetic waves emitted from multiple slots 20s of the resonator 20.

[0032] Refer to Figure 4 below. Figure 4 is a horizontal cross-sectional view showing another example of a resonator that may be used in the plasma processing apparatus shown in Figure 1. Figure 4 shows a horizontal cross-section of another example of resonator 20A, similar to Figure 2. Resonator 20A may be used as resonator 20 in the plasma processing apparatus 1 shown in Figure 1. Below, resonator 20A will be described in terms of its differences from resonator 20 shown in Figures 1 and 2.

[0033] The resonator 20A further includes multiple modification mechanisms 20v. The multiple modification mechanisms 20v are configured to change the effective circumferential length of each of the multiple slots 20s. In the resonator 20A, the circumferential lengths between one end and the other end of each of the multiple slots 20s (the circumferential lengths of the slots 20s when the screw 20ms of the modification mechanism 20v is not present) may be the same to one another.

[0034] In one embodiment, each of the multiple modification mechanisms 20v may include a plurality of screw holes 20sh and screws 20ms. The plurality of screw holes 20sh are arranged circumferentially along one of a pair of edges of a plurality of slots 20s that extend circumferentially along the corresponding slot and extend in a direction intersecting one of the pair of edges (e.g., radially). The plurality of screw holes 20sh are arranged circumferentially from one circumferential end of the corresponding slot.

[0035] The screw 20ms is screwed into at least one selected screw hole from a plurality of screw holes 20sh, traversing the corresponding slot radially and abutting against the other of a pair of circumferentially extending edges of the corresponding outer slot. With such a plurality of modification mechanisms 20v, each of the plurality of slots 20s has an effective length which is the circumferential distance between its other circumferential end and the screw 20ms. With such a plurality of modification mechanisms 20v, the circumferential effective length of each of the plurality of slots 20s can be set such that it becomes shorter as the circumferential distance between the circumferential center of each of the plurality of slots 20s and the reference plane RP increases.

[0036] Hereinafter, a plasma processing apparatus 1 according to yet another exemplary embodiment will be described with reference to Figures 5 and 6. Figure 5 is a diagram showing a plasma processing apparatus according to yet another exemplary embodiment. Figure 6 is a cross-sectional view taken along the line VI-VI in Figure 1. Hereinafter, the plasma processing apparatus 1B shown in Figure 5 will be described in terms of differences from the plasma processing apparatus 1 shown in Figures 1 and 2.

[0037] The plasma processing apparatus 1B includes an outer emission section 161 and an inner emission section 162 instead of an emission section 16. The outer emission section 161 and the inner emission section 162 are provided to radiate electromagnetic waves into the plasma generation space. The outer emission section 161 and the inner emission section 162 are formed from a dielectric material such as quartz, aluminum nitride, or aluminum oxide. The outer emission section 161 and the inner emission section 162 extend circumferentially around the axis AX. The outer emission section 161 extends radially with respect to the axis AX, outside the inner emission section 162. Each of the outer emission section 161 and the inner emission section 162 may have an annular shape.

[0038] In one embodiment, the plasma generation space extends within the processing space 10s and directly below the excitation electrode. In one embodiment, the excitation electrode includes a shower plate 22, and the plasma generation space is directly below the shower plate 22. The outer discharge section 161 and the inner discharge section 162 extend to surround the central portion of the shower plate 22, which has a plurality of gas holes 22h. The outer discharge section 161 and the inner discharge section 162 and the shower plate 22 are arranged to close the opening at the upper end of the chamber 10.

[0039] In the plasma processing apparatus 1B, electromagnetic waves emitted from the outer emission section 161 and the inner emission section 162 into the plasma generation space excite the gas in the plasma generation space, thereby generating plasma. The electromagnetic waves emitted from the outer emission section 161 and the inner emission section 162 into the plasma generation region may be high-frequency waves such as VHF waves or UHF waves.

[0040] The waveguide section 18 is configured to supply electromagnetic waves to the outer emission section 161 and the inner emission section 162. The waveguide section 18 includes a resonator 20B instead of the resonator 20. The resonator 20B will be described below in terms of its differences from the resonator 20.

[0041] The resonator 20B includes a waveguide 20w and a coupling 20p. The resonator 20B causes the electromagnetic waves input to the coupling 20p to resonate within the waveguide 20w and propagate toward the outer emission section 161 and the inner emission section 162. The electromagnetic waves are emitted from the outer emission section 161 and the inner emission section 162 into the plasma generation space.

[0042] In one embodiment, the wall of the resonator 20B may include an inner circumferential portion 20i, a first outer circumferential portion 20o1, and a second outer circumferential portion 20o2. The inner circumferential portion 20i extends around its central axis, axis AX, and has a substantially cylindrical shape. The first outer circumferential portion 20o1 and the second outer circumferential portion 20o2 each extend coaxially with the inner circumferential portion 20i around axis AX and have a substantially cylindrical shape. The second outer circumferential portion 20o2 extends radially with respect to axis AX, inside the first outer circumferential portion 20o1. The inner circumferential portion 20i, the first outer circumferential portion 20o1, and the second outer circumferential portion 20o2 each may be composed of a cylindrical plate-like body, or they may be composed of a plurality of columnar bodies arranged along the circumferential direction.

[0043] The waveguide 20w of the resonator 20B may have a layered structure that extends between the first outer periphery 20o1 and the inner periphery 20i, folds back along the inner periphery 20i, and extends between the inner periphery 20i and the second outer periphery 20o2. In this case, the walls of the waveguide 20w may include, in addition to the inner periphery 20i, the first outer periphery 20o1, and the second outer periphery 20o2, a plurality of walls that extend horizontally to form a layered structure.

[0044] Furthermore, the waveguide 20w of the resonator 20B may include an upper part 20a constituting the uppermost layer of the layered structure and a lower part 20b constituting the lowest layer of the layered structure. The upper part 20a may provide a first end 201, i.e., an upper end, at the first outer peripheral portion 20o1. The lower part 20b may provide a second end 202, i.e., a lower end, at the second outer peripheral portion 20o2.

[0045] Furthermore, the resonator 20B includes, instead of, multiple slots 20s, a plurality of outer slots 20s1 and a plurality of inner slots 20s2. The plurality of outer slots 20s1 extend circumferentially with respect to the axis AX. The plurality of outer slots 20s1 are arranged near and along the first end 201. The plurality of outer slots 20s1 are arranged circumferentially around the axis AX above the outer discharge portion 161. The plurality of outer slots 20s1 may be arranged at equal intervals along the circumferential direction.

[0046] Multiple inner slots 20s2 extend circumferentially with respect to the axis AX. Multiple inner slots 20s2 are arranged near the second end 202 and along the second end 202. Multiple inner slots 20s2 are arranged circumferentially around the axis AX above the inner discharge section 162. Multiple inner slots 20s2 may be arranged at equal intervals along the circumferential direction.

[0047] In one embodiment, the multiple inner slots 20s2 and the multiple outer slots 20s1 may be arranged alternately along the circumferential direction. That is, the multiple inner slots 20s2 and the multiple outer slots 20s1 may be arranged such that multiple radial lines connecting the axis AX to the centers of the multiple inner slots 20s2 and multiple radial lines connecting the axis AX to the multiple outer slots 20s1 are arranged alternately along the circumferential direction.

[0048] As shown in Figure 6, the direction in which the joint 20p is positioned relative to the axis AX may coincide with the direction in which the portion between two adjacent outer slots 20s1 in the circumferential direction is positioned relative to the axis AX. In this case, the direction in which the joint 20p is positioned relative to the axis AX may coincide with the direction in which the circumferential center of one of the multiple inner slots 20s2 is positioned relative to the axis AX. Alternatively, the direction in which the joint 20p is positioned relative to the axis AX may coincide with the direction in which the portion between two adjacent inner slots 20s2 in the circumferential direction is positioned relative to the axis AX. In this case, the direction in which the joint 20p is positioned relative to the axis AX may coincide with the direction in which the circumferential center of one of the multiple outer slots 20s1 is positioned relative to the axis AX. In either of these cases, the multiple outer slots 20s1 and the multiple inner slots 20s2 can be arranged symmetrically with respect to the longitudinal section including the joint 20p and the axis AX.

[0049] Multiple outer slots 20s1 electromagnetically couple the waveguide 20w and the outer emission section 161 to each other. Multiple outer slots 20s1 may also be electromagnetically coupled to the outer emission section 161 via waveguide 18w1. Waveguides 18w1 extend in a ring-like manner along the circumferential direction and are interposed between each of the multiple outer slots 20s1 and the outer emission section 161.

[0050] Multiple inner slots 20s2 electromagnetically couple the waveguide 20w and the inner emission section 162 to each other. Multiple inner slots 20s2 may also be electromagnetically coupled to the inner emission section 162 via waveguide 18w2. Waveguides 18w2 extend in a ring-like manner along the circumferential direction and are interposed between each of the multiple inner slots 20s2 and the inner emission section 162.

[0051] The effective circumferential length of each of the multiple outer slots 20s1 is set to decrease as the circumferential distance between the centers of each of the multiple outer slots 20s1 and the reference plane RP increases. The effective circumferential length of each of the multiple inner slots 20s2 is set to decrease as the circumferential distance between the centers of each of the multiple inner slots 20s2 and the reference plane RP increases. In the example in Figure 6, the effective length of each of the multiple outer slots 20s1 and the multiple inner slots 20s2 is the circumferential distance between one end and the other in the circumferential direction.

[0052] With this plasma processing apparatus 1B, it is possible to equalize the intensity of electromagnetic waves emitted from multiple outer slots 20s1 of the resonator 20B. Furthermore, it is possible to equalize the intensity of electromagnetic waves emitted from multiple inner slots 20s2 of the resonator 20B.

[0053] Furthermore, in the plasma processing apparatus 1B, electromagnetic wave resonance occurs between the first end 201 and the second end 202 of the resonator 20B. The electromagnetic waves that resonate in the resonator 20 are emitted into the plasma generation space through the outer emission section 161 from a plurality of outer slots 20s1, and also emitted into the plasma generation space through the inner emission section 162 from a plurality of inner slots 20s2. The electromagnetic waves emitted into the plasma generation space propagate along the lower surface of the shower plate 22 toward the center of the shower plate 22.

[0054] In the plasma processing apparatus 1B, the phases of the electromagnetic waves emitted into the plasma generation space through the outer emission section 161 and the phases of the electromagnetic waves emitted into the plasma generation space through the inner emission section 162 are different from each other, for example, by 180°. Therefore, the electromagnetic waves emitted into the plasma generation space through the outer emission section 161 and the electromagnetic waves emitted into the plasma generation space through the inner emission section 162 weaken each other. However, since the outer emission section 161 and the inner emission section 162 are formed at different positions in the radial direction, electromagnetic waves can exist as surface waves directly beneath the shower plate 22 in the vicinity of the outer emission section 161 and the inner emission section 162. Therefore, if only one of the outer emission section 161 or the inner emission section 162 is present, the intensity of the electromagnetic waves directly beneath the center of the shower plate 22 tends to be higher than the intensity of the electromagnetic waves at other locations. However, with the plasma processing apparatus 1B, it is possible to weaken the intensity of the electromagnetic waves directly beneath the center of the shower plate 22. Therefore, the plasma processing apparatus 1B makes it possible to improve the radial plasma density distribution in the plasma generation space.

[0055] The following describes the simulation results of the circumferential electric field strength distribution related to the plasma processing apparatus 1B. In the third simulation, the circumferential electric field strength distribution in waveguide 18w1 at a position 1 mm below each of the multiple outer slots 20s1 of the plasma processing apparatus 1 shown in Figures 5 and 6, and in waveguide 18w2 at a position 1 mm below each of the multiple inner slots 20s2 were determined. In the fourth simulation, as a comparative example, the circumferential electric field strength distribution in waveguides 18w1 and 18w2 was determined for a plasma processing apparatus identical to the plasma processing apparatus 1B shown in Figures 5 and 6, except that the effective circumferential lengths of each of the multiple outer slots 20s1 and each of the multiple inner slots 20s2 are the same, in the same manner as in the third simulation.

[0056] Figure 7(a) shows the simulation results of the circumferential electric field strength distribution in another example of a plasma processing apparatus, and represents the results of the third simulation. Figure 7(b) shows the simulation results of the circumferential electric field strength distribution in another comparative example of a plasma processing apparatus, and represents the results of the fourth simulation. In both Figure 7(a) and Figure 7(b), the horizontal axis represents the circumferential angle within waveguides 18w1 and 18w2 with reference to a plane extending symmetrically in the opposite direction to the reference plane RP with respect to the axis AX, and the vertical axis represents the electric field strength. In both Figure 7(a) and Figure 7(b), "outside" represents the electric field strength distribution within waveguide 18w1, and "inside" represents the electric field strength distribution within waveguide 18w2.

[0057] As can be seen from Figures 7(a) and 7(b), the variation in peak electric field strength in the electric field strength distribution within waveguides 18w1 and 18w2 obtained in the third simulation was smaller than the variation in peak electric field strength in the electric field strength distribution within waveguides 18w1 and 18w2 obtained in the fourth simulation. Therefore, it was confirmed that the plasma processing apparatus 1B makes it possible to equalize the intensity of electromagnetic waves emitted from multiple outer slots 20s1 of the resonator 20B, and to equalize the intensity of electromagnetic waves emitted from multiple inner slots 20s2.

[0058] Refer to Figure 8 below. Figure 8 is a horizontal cross-sectional view showing another example of a resonator that may be used in the plasma processing apparatus shown in Figure 5. Figure 8 shows a horizontal cross-section of another example of resonator 20C, similar to Figure 6. Resonator 20C may be used as resonator 20B in the plasma processing apparatus 1B shown in Figure 5. Below, resonator 20C will be described in terms of its differences from resonator 20B shown in Figures 5 and 6.

[0059] The resonator 20C further includes multiple modification mechanisms 20v similar to those of the resonator 20A. The multiple modification mechanisms 20v are configured to change the effective circumferential length of each of the multiple outer slots 20s1 and the multiple inner slots 20s2. In the resonator 20C, the circumferential length between one end and the other end of each of the multiple outer slots 20s1 (the circumferential length of the outer slot 20s1 assuming that the screw 20ms of the modification mechanism 20v does not exist) may be the same as those of the other. Also, in the resonator 20C, the circumferential length between one end and the other end of each of the multiple inner slots 20s2 (the circumferential length of the inner slot 20s2 assuming that the screw 20ms of the modification mechanism 20v does not exist) may be the same as those of the other.

[0060] Each of the multiple modification mechanisms 20v includes multiple screw holes 20sh and screws 20ms. The multiple screw holes 20sh are arranged circumferentially along one of a pair of edges that extend circumferentially along the corresponding slots among the multiple outer slots 20s1 and multiple inner slots 20s2, and extend in a direction intersecting one of the pair of edges (e.g., radially). The multiple screw holes 20sh are arranged circumferentially from one circumferential end of the corresponding slot.

[0061] The screw 20ms is screwed into at least one selected screw hole from a plurality of screw holes 20sh, and extends radially across the corresponding slot, abutting against the other of a pair of circumferentially extending edges of the corresponding outer slot. With such a plurality of modification mechanisms 20v, each of the plurality of outer slots 20s1 and the plurality of inner slots 20s2 has an effective length equal to the circumferential distance between its other circumferential end and the screw 20ms. With such a plurality of modification mechanisms 20v, the effective circumferential length of each of the plurality of outer slots 20s1 can be set to be shorter as the circumferential distance between the circumferential center of each of the plurality of outer slots 20s1 and the reference plane RP increases. Similarly, the effective circumferential length of each of the plurality of inner slots 20s2 can be set to be shorter as the circumferential distance between the circumferential center of each of the plurality of inner slots 20s2 and the reference plane RP increases.

[0062] Although various exemplary embodiments have been described above, the invention is not limited to the exemplary embodiments described above, and various additions, omissions, substitutions, and modifications may be made. Furthermore, it is possible to combine elements from different embodiments to form other embodiments.

[0063] For example, in plasma processing apparatuses 1 and 1B, the resonator may include a plurality of coupling portions 20p. In this case, the plurality of coupling portions 20p may be arranged rotationally symmetrically around the axis AX.

[0064] Furthermore, in the multiple slots 20s, each pair of adjacent slots along the circumferential direction (in Figures 2 and 4, each pair of adjacent slots in the semicircular area from 0° to 180° and the semicircular area from 180° to 360°) may have different effective circumferential lengths. In this case, the effective circumferential length of each of the multiple slots 20s may be set to equalize the intensity of electromagnetic waves emitted from the multiple slots 20s.

[0065] Furthermore, in the multiple outer slots 20s1, each pair of adjacent slots along the circumferential direction (in Figures 6 and 8, all adjacent pairs in each of the semicircular areas from 0° to 180° and from 180° to 360°) may have different effective circumferential lengths. Similarly, in the multiple inner slots 20s2, each pair of adjacent slots along the circumferential direction (in Figures 6 and 8, all adjacent pairs in each of the semicircular areas from 0° to 180° and from 180° to 360°) may have different effective circumferential lengths. In this case, the effective circumferential length of each of the multiple outer slots 20s1 may be set to equalize the intensity of electromagnetic waves emitted from the multiple inner slots. Similarly, the effective circumferential length of each of the multiple inner slots 20s2 may be set to equalize the intensity of electromagnetic waves emitted from the multiple inner slots.

[0066] Herein, various exemplary embodiments included in this disclosure are described in [E1] to [E20] below.

[0067] [E1] A chamber including a plasma generation space, An emission section is provided that extends circumferentially around the central axis of the chamber and the plasma generation space, and radiates electromagnetic waves from there into the plasma generation space, A waveguide unit configured to supply the electromagnetic waves to the emission unit, Equipped with, The waveguide section includes a resonator having a waveguide, The aforementioned resonator is, A coupling portion which is the entrance for electromagnetic waves located radially away from the central axis, The first end, which constitutes one end of the waveguide of the resonator and extends circumferentially around the central axis, The other end of the waveguide of the resonator has a second end that extends along the circumferential direction around the central axis, A plurality of slots are arranged along the second end and above the emission section, arranged circumferentially around the central axis, and electromagnetically coupling the waveguide and the emission section to each other. Includes, The effective length in the circumferential direction of each of the plurality of slots is set such that it becomes shorter as the circumferential distance between the center of each of the plurality of slots and a reference plane extending radially from the central axis through the joint parallel to the central axis is longer. Plasma processing equipment.

[0068] [E2] The plasma processing apparatus according to E1, wherein the effective length of each of the plurality of slots is the circumferential distance between one end and the other end of each of the plurality of slots.

[0069] [E3] The circumferential lengths between one end and the other end of each of the aforementioned plurality of slots are the same. The resonator further includes a plurality of modification mechanisms configured to change the effective length of each of the plurality of slots. The plasma processing apparatus described in E1.

[0070] [E4] Each of the above-mentioned multiple modification mechanisms is: A plurality of screw holes are arranged in the circumferential direction along one of a pair of edges that extend circumferentially along a corresponding slot among the plurality of slots, and which extend in a direction intersecting one of the pair of edges, A screw that is screwed into a selected screw hole from among the plurality of screw holes and abuts against the other of the pair of edges, A plasma processing apparatus as described in E3, including the one described above.

[0071] [E5] The plasma processing apparatus according to any one of E1 to E4, wherein the centers of each of the plurality of slots in the circumferential direction are arranged at equal intervals along the circumferential direction.

[0072] [E6] The aforementioned coupling portion is a single coupling portion, according to the plasma processing apparatus described in any one of E1 to E5.

[0073] [E7] The plasma processing apparatus according to any one of E1 to E6, wherein the direction in which the coupling portion is located relative to the central axis coincides with the direction in which the portion between two adjacent slots in the circumferential direction is located relative to the central axis.

[0074] [E8] The plasma processing apparatus according to any one of E1 to E6, wherein the direction in which the coupling portion is located relative to the central axis coincides with the direction in which the circumferential center of one of the plurality of slots is located relative to the central axis.

[0075] [E9] The aforementioned resonator is, An inner circumferential portion extending around the aforementioned central axis, The outer periphery extending around the aforementioned central axis, The waveguide having a layered structure that folds back between the outer periphery and the inner periphery, Located in the uppermost layer of the aforementioned layer structure, the upper part provides the first end in the outer peripheral portion, Located in the lowest layer of the aforementioned layer structure, the lower part provides the second end in the outer peripheral portion, A plasma processing apparatus as described in any one of items E1 to E8, including the one described above.

[0076] [E10] A chamber including a plasma generation space, An emission section is provided to extend circumferentially around the central axis of the chamber and the plasma generation space, and to radiate electromagnetic waves from there into the plasma generation space. A waveguide unit configured to supply the electromagnetic waves to the emission unit, Equipped with, The waveguide section includes a resonator having a waveguide, The aforementioned resonator is, A coupling portion which is the entrance for electromagnetic waves located radially away from the central axis, The first end, which constitutes one end of the waveguide of the resonator and extends circumferentially around the central axis, The other end of the waveguide of the resonator has a second end that extends along the circumferential direction around the central axis, A plurality of slots are arranged along the second end and above the emission section, arranged circumferentially around the central axis, and electromagnetically coupling the waveguide and the emission section to each other. Includes, In the plurality of slots, each pair of adjacent slots along the circumferential direction has different effective lengths in the circumferential direction. Plasma processing equipment.

[0077] [E11] The plasma processing apparatus according to E10, wherein the effective length in the circumferential direction of each of the plurality of slots is set to equalize the intensity of electromagnetic waves emitted from the plurality of slots.

[0078] [E12] The aforementioned discharge section is an inner discharge section, The aforementioned multiple slots are multiple inner slots, The aforementioned resonator is, An outer emission section extending circumferentially around the central axis of the chamber and the plasma generation space, and provided for radiating electromagnetic waves into the plasma generation space, the outer emission section extending radially with respect to the central axis outside the inner emission section, A plurality of outer slots are arranged along the first end and circumferentially around the central axis above the outer emission portion, and electromagnetically coupling the waveguide and the outer emission portion to each other, It further includes, The waveguide is configured to supply the electromagnetic waves to the outer emission section and the inner emission section. In the plurality of outer slots, each pair of adjacent slots along the circumferential direction has different effective lengths in the circumferential direction. A plasma processing apparatus described in E10.

[0079] [E13] The effective length in the circumferential direction of each of the plurality of inner slots is set to equalize the intensity of electromagnetic waves emitted from the plurality of inner slots. The effective length in the circumferential direction of each of the plurality of outer slots is set to equalize the intensity of electromagnetic waves emitted from the plurality of outer slots. Plasma processing apparatus as described in E12.

[0080] [E14] The effective length in the circumferential direction of each of the plurality of inner slots is set such that it becomes shorter as the circumferential distance between the center of each of the plurality of inner slots and a reference plane extending radially from the central axis through the joint parallel to the central axis is longer. The effective length in the circumferential direction of each of the plurality of outer slots is set such that the effective length in the circumferential direction of each of the plurality of outer slots becomes shorter as the distance in the circumferential direction from the reference plane increases. Plasma processing apparatus as described in E12.

[0081] [E15] The effective length of each of the plurality of inner slots is the circumferential distance between one end and the other end of each of the plurality of inner slots. The effective length of each of the plurality of outer slots is the circumferential distance between one end and the other end of each of the plurality of outer slots. A plasma processing apparatus as described in any one of items E12 to E14.

[0082] [E16] The circumferential lengths between one end and the other end of each of the plurality of inner slots are the same. The circumferential lengths between one end and the other end of each of the plurality of outer slots are the same. The resonator further includes a plurality of modification mechanisms configured to change the effective length of each of the plurality of inner slots and the plurality of outer slots. A plasma processing apparatus as described in any one of items E12 to E14.

[0083] [E17] Each of the above-mentioned multiple modification mechanisms is: A plurality of screw holes are arranged in the circumferential direction along one of a pair of edges that extend circumferentially along a corresponding slot among the plurality of inner slots and the plurality of outer slots, and which extend in a direction intersecting one of the pair of edges, A screw that is screwed into a selected screw hole from among the plurality of screw holes and abuts against the other of the pair of edges, A plasma processing apparatus as described in E16, including the one described above.

[0084] [E18] The plasma processing apparatus according to any one of E12 to E17, wherein the plurality of inner slots and the plurality of outer slots are arranged alternately along the circumferential direction.

[0085] [E19] The centers of the plurality of inner slots in the circumferential direction are arranged at equal intervals in the circumferential direction. The centers of the plurality of outer slots in the circumferential direction are arranged at equal intervals in the circumferential direction. A plasma processing apparatus as described in any one of items E12 to E18.

[0086] [E20] The aforementioned resonator is, An inner circumferential portion extending around the aforementioned central axis, A first outer periphery extending around the aforementioned central axis, A second outer periphery extending inside the first outer periphery around the central axis, The waveguide has a layered structure that extends between the first outer periphery and the inner periphery, folds back along the inner periphery, and extends between the inner periphery and the second outer periphery, Located in the uppermost layer of the aforementioned layer structure, the upper part provides the first end in the first outer periphery, Located in the lowest layer of the aforementioned layer structure, the lower part provides the second end in the second outer periphery, A plasma processing apparatus as described in any one of items E12 to E19, including the one described above.

[0087] From the above description, it will be understood that the various embodiments of this disclosure are described herein for illustrative purposes and can be modified in various ways without departing from the scope and spirit of this disclosure. Accordingly, the various embodiments disclosed herein are not intended to limit the scope and spirit, and the true scope and spirit are shown by the appended claims. [Explanation of Symbols]

[0088] 1,1B...Plasma processing device, 10...Chamber, 16...Emission section, 161...Outer emission section, 162...Inner emission section, 18...Waveguide section, 20,20A,20B,20C...Resonators, 20w...Waveguide, 201...First end, 202...Second end, 20s...Slot, 20s1...Outer slot, 20s2...Inner slot, 20v...Modification mechanism.

Claims

1. A chamber including a plasma generation space, An emission section is provided that extends circumferentially around the central axis of the chamber and the plasma generation space, and radiates electromagnetic waves from there into the plasma generation space, A waveguide unit configured to supply the electromagnetic waves to the emission unit, Equipped with, The waveguide section includes a resonator having a waveguide, The aforementioned resonator is A coupling portion which is the entrance for electromagnetic waves located radially away from the central axis, A first end that constitutes one end of the waveguide of the resonator and extends circumferentially around the central axis, The other end of the waveguide of the resonator has a second end that extends along the circumferential direction around the central axis, A plurality of slots are arranged along the second end and above the emission section, arranged circumferentially around the central axis, and electromagnetically coupling the waveguide and the emission section to each other. Includes, The effective length in the circumferential direction of each of the plurality of slots is set such that it becomes shorter as the circumferential distance between the center of each of the plurality of slots and a reference plane extending radially from the central axis through the joint parallel to the central axis is longer. Plasma processing equipment.

2. The plasma processing apparatus according to claim 1, wherein the effective length of each of the plurality of slots is the circumferential distance between one end and the other end of each of the plurality of slots.

3. The circumferential lengths between one end and the other end of each of the aforementioned plurality of slots are the same. The resonator further includes a plurality of modification mechanisms configured to change the effective length of each of the plurality of slots. The plasma processing apparatus according to claim 1.

4. Each of the above-mentioned multiple modification mechanisms is: A plurality of screw holes are arranged in the circumferential direction along one of a pair of edges that extend circumferentially along a corresponding slot among the plurality of slots, and which extend in a direction intersecting one of the pair of edges, A screw that is screwed into a selected screw hole from among the plurality of screw holes and abuts against the other of the pair of edges, The plasma processing apparatus according to claim 3, including the following:

5. The plasma processing apparatus according to any one of claims 1 to 4, wherein the circumferential centers of each of the plurality of slots are arranged at equal intervals along the circumferential direction.

6. The plasma processing apparatus according to any one of claims 1 to 4, wherein the coupling portion is a single coupling portion.

7. The plasma processing apparatus according to any one of claims 1 to 4, wherein the direction in which the coupling portion is located relative to the central axis coincides with the direction in which the portion between two adjacent slots in the circumferential direction among the plurality of slots is located relative to the central axis.

8. The plasma processing apparatus according to any one of claims 1 to 4, wherein the direction in which the coupling portion is located relative to the central axis coincides with the direction in which the circumferential center of one of the plurality of slots is located relative to the central axis.

9. The aforementioned resonator is An inner circumferential portion extending around the aforementioned central axis, The outer periphery extending around the aforementioned central axis, The waveguide having a layered structure that folds back between the outer periphery and the inner periphery, Located in the uppermost layer of the aforementioned layer structure, the upper part provides the first end in the outer peripheral portion, Located in the lowest layer of the aforementioned layer structure, the lower part provides the second end in the outer peripheral portion, A plasma processing apparatus according to any one of claims 1 to 4, including the following:

10. A chamber including a plasma generation space, An emission section is provided to extend circumferentially around the central axis of the chamber and the plasma generation space, and to radiate electromagnetic waves from there into the plasma generation space. A waveguide unit configured to supply the electromagnetic waves to the emission unit, Equipped with, The waveguide section includes a resonator having a waveguide, The aforementioned resonator is A coupling portion which is the entrance for electromagnetic waves located radially away from the central axis, A first end that constitutes one end of the waveguide of the resonator and extends circumferentially around the central axis, The other end of the waveguide of the resonator has a second end that extends along the circumferential direction around the central axis, A plurality of slots are arranged along the second end and above the emission section, arranged circumferentially around the central axis, and electromagnetically coupling the waveguide and the emission section to each other. Includes, In the plurality of slots, each pair of adjacent slots along the circumferential direction has different effective lengths in the circumferential direction. Plasma processing equipment.

11. The plasma processing apparatus according to claim 10, wherein the effective length in the circumferential direction of each of the plurality of slots is set to equalize the intensity of electromagnetic waves emitted from the plurality of slots.

12. The aforementioned discharge section is an inner discharge section, The aforementioned multiple slots are multiple inner slots, The aforementioned resonator is An outer emission section extending circumferentially around the central axis of the chamber and the plasma generation space, and provided for radiating electromagnetic waves into the plasma generation space, the outer emission section extending radially with respect to the central axis outside the inner emission section, A plurality of outer slots are arranged along the first end and above the outer emission portion, arranged circumferentially around the central axis, and electromagnetically coupling the waveguide and the outer emission portion to each other. It further includes, The waveguide is configured to supply the electromagnetic waves to the outer emission section and the inner emission section. In the plurality of outer slots, each pair of adjacent slots along the circumferential direction has different effective lengths in the circumferential direction. The plasma processing apparatus according to claim 10.

13. The effective length in the circumferential direction of each of the plurality of inner slots is set to equalize the intensity of electromagnetic waves emitted from the plurality of inner slots. The effective length in the circumferential direction of each of the plurality of outer slots is set to equalize the intensity of electromagnetic waves emitted from the plurality of outer slots. The plasma processing apparatus according to claim 12.

14. The effective length in the circumferential direction of each of the plurality of inner slots is set such that it becomes shorter as the circumferential distance between the center of each of the plurality of inner slots and a reference plane extending radially from the central axis through the joint parallel to the central axis is longer. The effective length in the circumferential direction of each of the plurality of outer slots is set such that the effective length in the circumferential direction of each of the plurality of outer slots becomes shorter as the distance in the circumferential direction from the reference plane increases. The plasma processing apparatus according to claim 12.

15. The effective length of each of the plurality of inner slots is the circumferential distance between one end and the other end of each of the plurality of inner slots. The effective length of each of the plurality of outer slots is the circumferential distance between one end and the other end of each of the plurality of outer slots. A plasma processing apparatus according to any one of claims 12 to 14.

16. The circumferential lengths between one end and the other end of each of the plurality of inner slots are the same. The circumferential lengths between one end and the other end of each of the plurality of outer slots are the same. The resonator further includes a plurality of modification mechanisms configured to change the effective length of each of the plurality of inner slots and the plurality of outer slots. A plasma processing apparatus according to any one of claims 12 to 14.

17. Each of the above-mentioned multiple modification mechanisms is: A plurality of screw holes are arranged in the circumferential direction along one of a pair of edges that extend circumferentially along a corresponding slot among the plurality of inner slots and the plurality of outer slots, and which extend in a direction intersecting one of the pair of edges, A screw that is screwed into a selected screw hole from among the plurality of screw holes and abuts against the other of the pair of edges, The plasma processing apparatus according to claim 16, including the following:

18. The plasma processing apparatus according to any one of claims 12 to 14, wherein the plurality of inner slots and the plurality of outer slots are arranged alternately along the circumferential direction.

19. The centers of the plurality of inner slots in the circumferential direction are arranged at equal intervals in the circumferential direction. The centers of the plurality of outer slots in the circumferential direction are arranged at equal intervals in the circumferential direction. A plasma processing apparatus according to any one of claims 12 to 14.

20. The aforementioned resonator is An inner circumferential portion extending around the aforementioned central axis, A first outer periphery extending around the aforementioned central axis, A second outer periphery extending inside the first outer periphery around the central axis, The waveguide has a layered structure that extends between the first outer periphery and the inner periphery, folds back along the inner periphery, and extends between the inner periphery and the second outer periphery, Located in the uppermost layer of the aforementioned layer structure, the upper part provides the first end in the first outer periphery, Located in the lowest layer of the aforementioned layer structure, the lower part provides the second end in the second outer periphery, A plasma processing apparatus according to any one of claims 12 to 14, including the following:

Images