Plasma processing apparatus and plasma generation method

Abstract

This technology provides an improvement to the radial plasma density distribution in the plasma generation space. [Solution] The disclosed plasma processing apparatus includes a chamber, an outer emission section, an inner emission section, and a waveguide. The outer emission section and the inner emission section extend circumferentially around the central axis of the plasma generation space of the chamber. The waveguide includes a resonator. The resonator includes a first end, a second end, a plurality of inner slots, and a plurality of outer slots. The first end and the second end constitute one end and the other end of the waveguide of the resonator, respectively, and extend circumferentially around the central axis. The plurality of inner slots are arranged along the second end and aligned circumferentially, electromagnetically coupling the waveguide and the inner emission section to each other. The plurality of outer slots are arranged along the first end and aligned circumferentially, electromagnetically coupling the waveguide and the outer emission section to each other.

Description

Technical Field

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

Background Art

[0002] A plasma processing apparatus is used in processing a substrate. As one type of plasma processing apparatus, there is known one that excites a gas using a high frequency that is a VHF wave or a UHF wave. 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 a 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 circumferentially around the central axis of the processing container. The waveguide part is configured to supply a high frequency to the introduction part. The waveguide part includes a resonator that provides a waveguide. The waveguide of the resonator extends circumferentially around the central axis and 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] The present disclosure provides a technique for improving the radial plasma density distribution in a plasma generation space.

Means for Solving the Problems

[0005] In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, an outer emission section, an inner emission section, and a waveguide. The chamber includes a plasma generation space. The outer emission section and the inner emission section extend circumferentially around the central axis of the chamber and the plasma generation space and are provided to radiate electromagnetic waves from there into the plasma generation space. The outer emission section extends radially with respect to the central axis, outside the inner emission section. The waveguide is configured to supply electromagnetic waves to the emission section. The waveguide includes a resonator having a waveguide. The resonator includes a first end, a second end, a plurality of inner slots, and a plurality of outer slots. 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. Multiple inner slots are arranged along the second end and circumferentially around the central axis above the inner emission section, electromagnetically coupling the waveguide and the inner emission section to each other. Multiple outer slots are arranged along the first end and circumferentially around the central axis above the outer emission section, electromagnetically coupling the waveguide and the outer emission section to each other. [Effects of the Invention]

[0006] According to one exemplary embodiment, it is possible to improve the radial plasma density distribution in the plasma generation space. [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] This figure shows a plasma processing apparatus according to another exemplary embodiment. [Figure 4] This is a cross-sectional view taken along the line IV-IV in Figure 3. [Figure 5] This figure shows an example of a switching circuit that can be used in the plasma processing apparatus shown in Figure 3. [Figure 6] This figure shows a plasma processing apparatus according to yet another exemplary embodiment. [Figure 7] This is a cross-sectional view taken along the line VII-VII in Figure 6. [Figure 8] This is a cross-sectional view taken along the line VIII-VIII in Figure 6. [Figure 9] This table shows examples of the first to third states formed in the plasma processing apparatus shown in Figure 6. [Figure 10] This is a flowchart illustrating a plasma generation method according to one exemplary embodiment. [Figure 11] This is a flowchart illustrating a plasma generation method according to another exemplary embodiment. [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 outer emission section 161, an inner emission section 162, and a waveguide section 18. The plasma processing apparatus 1 may further include a substrate support section 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 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.

[0014] In one embodiment, the plasma generation space extends within the processing space for 10 s 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 outer discharge portion 161 and the inner discharge portion 162 extend so as to surround the central portion of the shower plate 22 having the plurality of gas holes 22h. The outer discharge portion 161, the inner discharge portion 162, and the shower plate 22 are arranged 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 portion 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 portion 26 is connected to the gas diffusion space 14d. The gas output from the gas supply portion 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 waves emitted from the outer discharge portion 161 and the inner discharge portion 162 into the plasma generation space, and plasma is generated. The electromagnetic waves emitted from the outer discharge portion 161 and the inner discharge portion 162 into the plasma generation region may be high-frequency waves such as VHF waves or UHF waves.

[0018] 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 20. The resonator 20 may be located above the chamber 10. The resonator 20 has a waveguide 20w.

[0019] The resonator 20 includes a coupling section 20p, which is the electromagnetic wave inlet for the waveguide 20w. The electromagnetic wave is generated based on high-frequency power generated by a high-frequency power supply 24. The high-frequency power supply 24 may be configured to change the frequency of the high-frequency power it outputs. The high-frequency power supply 24 is electrically connected to the coupling section 20p. The high-frequency power supply 24 and the coupling section 20p may be electrically connected via a coaxial connector 25. The resonator 20 resonates the electromagnetic wave input to the coupling section 20p within the waveguide 20w and propagates it toward the outer emission section 161 and the inner emission section 162. The electromagnetic wave is emitted from the outer emission section 161 and the inner emission section 162 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 from a material such as metal. The walls of the waveguide 20w may be formed from aluminum alloy, copper, nickel, or stainless steel, 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 circumferentially around the axis AX. The second end 202 also extends circumferentially around the axis AX.

[0022] In one embodiment, the wall of the resonator 20 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.

[0023] The waveguide 20w may have a layered structure that extends between a first outer circumferential portion 20o1 and an inner circumferential portion 20i, folds back along the inner circumferential portion 20i, and extends between the inner circumferential portion 20i and a second outer circumferential portion 20o2. In this case, the walls of the waveguide 20w may include, in addition to the inner circumferential portion 20i, the first outer circumferential portion 20o1, and the second outer circumferential portion 20o2, 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 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.

[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] The resonator 20 further includes 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 the first end 201 and along the first end 201. The plurality of outer slots 20s1 are arranged circumferentially around the axis AX above the outer emission section 161. The plurality of outer slots 20s1 may be arranged at equal intervals along the circumferential direction. The plurality of outer slots 20s1 electromagnetically couple the waveguide 20w and the outer emission section 161 to each other.

[0027] 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 emission section 162. Multiple inner slots 20s2 may be arranged at equal intervals along the circumferential direction. Multiple inner slots 20s2 electromagnetically couple the waveguide 20w and the inner emission section 162 to each other.

[0028] 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.

[0029] In one embodiment, the resonator 20 may further include a plurality of modification mechanisms 20v. In the example shown in Figures 1 and 2, the plurality of modification mechanisms 20v are configured to change the length of each of the plurality of outer slots 20s1 along the circumferential direction (effective length of the slot). The effective length of the slot in the circumferential direction is the length of the portion of the slot that effectively contributes to the emission of electromagnetic waves.

[0030] Each of the multiple modification mechanisms 20v includes multiple screw holes 20sh and at least one screw 20ms. The multiple screw holes 20sh are circumferentially arranged along one of a pair of edges that extend circumferentially along the corresponding outer slot of a plurality of outer slots 20s1 and extend in a direction intersecting one of the pair of edges (e.g., radially). Half of the multiple screw holes 20sh may be arranged circumferentially from one circumferential end of the corresponding outer slot, and the other half of the multiple screw holes 20sh may be arranged circumferentially from the other circumferential end of the corresponding outer slot.

[0031] At least one screw 20ms is screwed into at least one selected screw hole 20sh from a plurality of screw holes 20sh, extending radially across the corresponding outer slot and contacting the other of a pair of edges extending circumferentially from the corresponding outer slot. In each of the plurality of modification mechanisms 20v, an even number of screws 20ms may be screwed into a selected even number of screw holes 20sh such that the circumferential length of the corresponding outer slot is changed without changing the circumferential center position of the corresponding outer slot. With such plurality of modification mechanisms 20v, the circumferential length of the plurality of outer slots 20s1 can be adjusted, and the intensity of electromagnetic waves (electric field strength) emitted from the plurality of outer slots 20s1 can be adjusted.

[0032] In the plasma processing apparatus 1, electromagnetic wave resonance occurs between the first end 201 and the second end 202 of the resonator 20. 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.

[0033] In the plasma processing apparatus 1, the phases of electromagnetic waves emitted into the plasma generation space through the outer emission section 161 and the phases of 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, without the outer emission section 161, the intensity of electromagnetic waves directly beneath the center of the shower plate 22 tends to be higher than the intensity of electromagnetic waves at other locations, but the plasma processing apparatus 1 makes it possible to weaken the intensity of electromagnetic waves directly beneath the center of the shower plate 22. Thus, the plasma processing apparatus 1 makes it possible to improve the radial plasma density distribution in the plasma generation space.

[0034] Furthermore, the plasma processing apparatus 1 allows for the relative adjustment of the intensity of electromagnetic waves emitted from the outer emission section 161 into the plasma generation space to the intensity of electromagnetic waves emitted from the inner emission section 162 into the plasma generation space, using multiple modification mechanisms 20v. Therefore, the plasma processing apparatus 1 makes it possible to adjust the radial distribution of electromagnetic wave intensity in the plasma generation space. Consequently, the plasma processing apparatus 1 makes it possible to adjust the radial plasma density distribution in the plasma generation space.

[0035] Furthermore, the multiple modification mechanisms 20v may be provided in addition to, or in place of, the multiple outer slots 20s1, so as to be able to change the length of the multiple inner slots 20s2.

[0036] Hereinafter, a plasma processing apparatus according to another exemplary embodiment will be described with reference to Figures 3 and 4. Figure 3 is a diagram showing a plasma processing apparatus according to another exemplary embodiment. Figure 4 is a cross-sectional view taken along line IV-IV in Figure 3. Hereinafter, the plasma processing apparatus 1B shown in Figures 3 and 4 will be described in terms of differences from the plasma processing apparatus 1.

[0037] The plasma processing apparatus 1B does not include multiple modification mechanisms 20v. In the plasma processing apparatus 1B, the resonator 20 further includes multiple short-circuit mechanisms 50. The multiple short-circuit mechanisms 50 are configured to releasably short-circuit multiple portions 20sp, which are the central portions in the circumferential direction of each of the multiple outer slots 20s1, to ground.

[0038] Each of the multiple short-circuit mechanisms 50 includes a metal rod 51i and a switching circuit 53. Each rod 51i of the multiple short-circuit mechanisms 50 extends radially across a corresponding portion of a plurality of parts 20sp. That is, each rod 51i of the multiple short-circuit mechanisms 50 extends radially across the central portion in the circumferential direction of a corresponding outer slot of a plurality of outer slots 20s1. One end of each rod 51i of the multiple short-circuit mechanisms 50 may be connected to the outer surface of a bottom plate 20bp that defines the inner edge of the corresponding outer slot. The rod 51i may be an inner conductor of the coaxial tube 51. In this case, the outer conductor 51o of the coaxial tube 51 is connected to the first outer periphery 20o1.

[0039] Each rod 51i of the multiple short-circuiting mechanisms 50 is connected to a switching circuit 53 on a control circuit board. The control circuit board is housed in a shielded case 52. The switching circuit 53 is configured to releasably short-circuit the rods 51i to ground. The switching circuit 53 can have any circuit configuration as long as it can switch between short-circuiting the rods 51i to ground and releasing the short circuit.

[0040] Figure 5 shows an example of a switching circuit that can be used in the plasma processing apparatus shown in Figure 3. In one embodiment, the switching circuit 53 may have the configuration shown in Figure 5. In the example of Figure 5, the switching circuit 53 includes a diode 53d, a first switching transistor 53t1, a second switching transistor 53t2, a current source 53i, a voltage source 53v, a signal generation circuit 53p1, and a signal generation circuit 53p2.

[0041] The anode of diode 53d is connected to rod 51i. The cathode of diode 53d may be connected to ground via capacitor 53c. Diode 53d may be a PIN diode or a Schottky diode, etc. Diode 53d may be a diode with a small capacitance when OFF. Capacitor 53c may have a capacitance determined to provide a sufficiently small impedance at the plasma excitation frequency and may have small losses. Capacitor 53c may be a ceramic capacitor, etc.

[0042] Each of the first switching transistor 53t1 and the second switching transistor 53t2 may be a switching transistor such as a MOSFET. Each of the first switching transistor 53t1 and the second switching transistor 53t2 is connected in parallel between the cathode of diode 53d and ground.

[0043] The current source 53i is, for example, a constant current source and is connected between the first switching transistor 53t1 and ground. The voltage source 53v is, for example, a constant voltage source and is connected between the second switching transistor 53t2 and ground.

[0044] The current value Is of the current source 53i is set to a value greater than the amplitude (peak amplitude relative to 0) of the high-frequency current Im flowing through the rod 51i. The high-frequency current Im is the current that flows through the rod 51i when the rod 51i, which is located in the corresponding part of the multiple parts 20sp in the plasma excitation conditions of the plasma processing apparatus 1, is short-circuited to ground. In addition, the voltage value Vs of the voltage source 53v is set to a value greater than the amplitude (peak amplitude relative to 0) of the high-frequency voltage Vm applied to the rod 51i in the plasma excitation conditions of the plasma processing apparatus 1.

[0045] The signal generation circuit 53p1 is connected to the control terminal of the first switching transistor 53t1. The signal generation circuit 53p1 switches the first switching transistor 53t1 between ON (closed state) and OFF (open state) by applying a control signal to the control terminal of the first switching transistor 53t1. The signal generation circuit 53p2 is connected to the control terminal of the second switching transistor 53t2. The signal generation circuit 53p2 switches the second switching transistor 53t2 between ON (closed state) and OFF (open state) by applying a control signal to the control terminal of the second switching transistor 53t2. The signal generation circuits 53p1 and 53p2 alternately set the first switching transistor 53t1 and the second switching transistor 53t2 to ON (closed state). Note that the signal generation circuits 53p1 and 53p2 may be controlled by a control circuit 2 composed of a dedicated circuit such as a computer device or ASIC.

[0046] When the first switching transistor 53t1 in the switching circuit 53 is ON (closed), a forward current flows through the diode 53d. As a result, the corresponding outer slot is short-circuited to ground at its center, effectively blocking the emission of electromagnetic waves from that outer slot. On the other hand, when the second switching transistor 53t2 is ON (closed), a reverse voltage is applied to the diode 53d, releasing the short circuit at the center of the corresponding outer slot, and electromagnetic waves are emitted from that outer slot towards the outer emission section 161.

[0047] According to the plasma processing apparatus 1B, it is possible to adjust the time average intensity of electromagnetic waves emitted from multiple outer slots 20s1 by alternately switching between the emission and blocking of electromagnetic waves from multiple outer slots 20s1. Therefore, according to the plasma processing apparatus 1B, it is possible to adjust the radial distribution of electromagnetic wave intensity in the plasma generation space and to adjust the radial plasma density distribution in the plasma generation space.

[0048] Furthermore, the multiple short-circuit mechanisms 50 may be configured to switch between short-circuiting and releasing the short circuit in multiple sections 20sp with a period of 1 μs to 100 μs. In this case, since the short-circuiting and releasing of the short circuit in multiple sections 20sp are switched with a period that does not cause the plasma to respond, it becomes possible to adjust the radial plasma density distribution in the plasma generation space without changing it over time.

[0049] Furthermore, the multiple short-circuit mechanisms 50 may be configured to short-circuit multiple portions of each of the multiple inner slots 20s2, which are the central portions in the circumferential direction, to ground in a releaseable manner, in addition to or instead of the multiple outer slots 20s1.

[0050] Hereinafter, a plasma processing apparatus according to yet another exemplary embodiment will be described with reference to Figures 6 to 8. Figure 6 is a diagram showing a plasma processing apparatus according to yet another exemplary embodiment. Figure 7 is a cross-sectional view taken along line VII-VII in Figure 6. Figure 8 is a cross-sectional view taken along line VIII-VIII in Figure 6. Hereinafter, the plasma processing apparatus 1C shown in Figures 6 to 8 will be described in terms of differences from the plasma processing apparatus 1B.

[0051] The plasma processing apparatus 1C includes multiple short-circuit mechanisms 50C instead of multiple short-circuit mechanisms 50. The multiple short-circuit mechanisms 50C are configured to releasably short-circuit multiple portions 20sp of the waveguide 20w along the central portion in the circumferential direction of each of the multiple outer slots 20s1 to ground. The multiple portions 20sp are arranged circumferentially within the upper part 20a. The multiple portions 20sp are located radially inward near the central portion in the circumferential direction of each of the multiple outer slots 20s1.

[0052] Each of the multiple short-circuit mechanisms 50C includes a switching circuit 53, similar to each of the multiple short-circuit mechanisms 50. In each of the multiple short-circuit mechanisms 50C, the control circuit board providing the switching circuit 53 is located in a space formed in the upper wall of a resonator 20 that defines the upper part 20a from above, and is shielded by a cover 52C that closes the space.

[0053] A metal rod 51C is connected to the switching circuit 53. In the example of the switching circuit 53 in Figure 5, the rod 51C is connected to the anode of the diode 53d. One end of the rod 51C may be connected to the wall of the resonator 20 that defines the upper part 20a from below.

[0054] In the plasma processing apparatus 1C, multiple short-circuiting mechanisms 50C can switch between short-circuiting and unshort-circuiting the central portion of multiple outer slots 20s1. In the plasma processing apparatus 1C, by alternately switching between emitting and blocking electromagnetic waves from multiple outer slots 20s1, it is possible to adjust the time average intensity of electromagnetic waves emitted from multiple outer slots 20s1. Therefore, with the plasma processing apparatus 1C, it is possible to adjust the radial distribution of electromagnetic wave intensity in the plasma generation space, and thus the radial plasma density distribution in the plasma generation space.

[0055] Figure 9 is a table showing examples of the first to third states formed in the plasma processing apparatus shown in Figure 6. In the plasma processing apparatus 1C, the multiple short-circuit mechanisms 50C may repeatedly perform the process of sequentially forming the first to third states shown in Figure 9. In this case, the multiple outer slots 20s1 include a plurality of first outer slots 20s11 and a plurality of second outer slots 20s12 arranged alternately along the circumferential direction. The multiple parts 20sp include a plurality of first parts 20sp1 and a plurality of second parts 20sp2. The plurality of first parts 20sp1 are arranged along the circumferential central portion of the plurality of first outer slots 20s11. The plurality of second parts 20sp2 are arranged along the circumferential central portion of the plurality of second outer slots 20s12.

[0056] In Figure 9, the numbers in parentheses after the reference numerals of the multiple first outer slots 20s11, multiple first parts 20sp1, multiple second outer slots 20s12, and multiple second parts 20sp2 indicate their order in the circumferential direction. In the example shown in Figure 9, the multiple short-circuit mechanism 50C forms a first state in which the multiple first parts 20sp1 are released from the ground and the multiple second parts 20sp2 are short-circuited to the ground. In the first state, electromagnetic waves are emitted from the multiple first outer slots 20s11 and the emission of electromagnetic waves from the multiple second outer slots 20s12 is blocked.

[0057] The multiple short-circuit mechanism 50C, after the first state, forms a second state in which multiple first parts 20sp1 are short-circuited to ground and multiple second parts 20sp2 are released from the ground. In the second state, electromagnetic wave emission from multiple first outer slots 20s11 is blocked and electromagnetic wave emission from multiple second outer slots 20s12 is permitted.

[0058] The multiple short-circuit mechanisms 50C form a third state after the second state in which the multiple first parts 20sp1 and the multiple second parts 20sp2 are short-circuited to ground. In the third state, the emission of electromagnetic waves from the multiple first outer slots 20s11 and the multiple second outer slots 20s12 is blocked.

[0059] In the example shown in Figure 9, it is possible to adjust the radial distribution of electromagnetic wave intensity in the plasma generation space, and thus adjust the radial plasma density distribution in the plasma generation space. Furthermore, in the first and second states, electromagnetic wave losses in each part are reduced, and high power efficiency is obtained.

[0060] In the plasma processing apparatus 1C, the first to third states may be switched with a period of 1 μs or more and 100 μs or less. That is, the time length of the period for repeating the formation of the first to third states may be 1 μs or more and 100 μs or less. The time lengths of the first state and the second state may be equal to each other, and the time length of the third state may be set so that the plasma is generated most uniformly. In this case, since the short-circuiting and release of the short-circuiting to ground in multiple sections 20sp are switched with a period of so little that the plasma does not respond, it becomes possible to adjust the radial plasma density distribution in the plasma generation space without changing it over time.

[0061] Furthermore, the multiple short-circuit mechanisms 50C may be configured to short-circuit to ground a plurality of portions 20sp arranged along the central portion in the circumferential direction of each of the plurality of inner slots 20s2, in addition to or instead of the plurality of outer slots 20s1. Also, the repetition of the formation of the first to third states in the example shown in Figure 9 may be performed in the plasma processing apparatus 1B.

[0062] A plasma generation method according to one exemplary embodiment will be described below with reference to Figure 10. The plasma generation method shown in Figure 10 (hereinafter referred to as "Method MTA") is applied to the plasma processing apparatus 1B or the plasma processing apparatus 1C.

[0063] Method MTA includes steps STAa and STAb. In step STAa, electromagnetic waves are supplied to a plurality of outer slots 20s1 and a plurality of inner slots 20s2 via waveguide 20w to supply electromagnetic waves to the plasma generation space.

[0064] Process STAb is performed in parallel with process STAa. In process STAb, the amount of electromagnetic waves emitted from multiple inner slots 20s2 and / or multiple outer slots 20s1 is adjusted. To this end, multiple short-circuiting mechanisms (50 or 50C) adjust the short-circuiting and release of multiple sections 20sp to ground. For the operation of the multiple short-circuiting mechanisms (50 or 50C), please refer to the above description of plasma processing apparatus 1B and plasma processing apparatus 1C.

[0065] Method MTA may further include process STJA. In process STJA, it is determined whether or not a stop condition is met. The stop condition is met if the process termination condition is met. If it is determined in process STJA that the stop condition is not met, process STAb is repeated in parallel with process STAa. In the repetition of process STAb, the short-circuiting to ground in multiple parts 20sp and the release of said short-circuiting may be switched with a period of 1 μs or more and 100 μs or less. On the other hand, if it is determined in process STJA that the stop condition is met, Method MTA terminates.

[0066] The plasma generation method according to another exemplary embodiment will be described below with reference to Figure 11. The plasma generation method shown in Figure 11 (hereinafter referred to as "Method MTB") is applied to the plasma processing apparatus 1B or the plasma processing apparatus 1C.

[0067] Method MTB includes steps STBa to STBe. In step STBa, electromagnetic waves are supplied to multiple outer slots 20s1 and multiple inner slots 20s2 via waveguide 20w to supply electromagnetic waves to the plasma generation space.

[0068] Processes STBb to STBe are performed in parallel with process STBa. In processes STBb to STBd, the first to third states described above are formed in order. In process STBe, processes STBb to STBd are repeated. Processes STBb to STBd may be repeated with a period of 1 μs or more and 100 μs or less.

[0069] Process STBe may further include process STJB. Process STJB determines whether or not a termination condition is met. The termination condition is met if the process termination condition is met. If it is determined in process STJB that the termination condition is not met, processes STBb to STBd are repeated in parallel with process STBa. On the other hand, if it is determined in process STJB that the termination condition is met, method MTB terminates.

[0070] 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.

[0071] For example, in the above embodiment, the outer discharge portion 161 and the inner discharge portion 162 were separate parts, but in other embodiments, the outer discharge portion 161 and the inner discharge portion 162 may be composed of a single object or one integrated object made of a dielectric material. That is, embodiments in which a portion of a single object or one integrated object made of a dielectric material that corresponds to a plurality of outer slots 20s1 is used as the outer discharge portion 161, and another portion of the object that corresponds to a plurality of inner slots 20s2 is used as the inner discharge portion 162 are also included in the scope of this disclosure.

[0072] Herein, various exemplary embodiments included in this disclosure are described in [E1] to [E15] below.

[0073] [E1] A chamber including a plasma generation space, An outer emission section and an inner emission section are provided to extend circumferentially around the central axis of the chamber and the plasma generation space and to radiate electromagnetic waves from thereto into the plasma generation space, wherein the outer emission section extends radially with respect to the central axis outside the inner emission section, and the outer emission section and the inner emission section, A waveguide configured to supply the electromagnetic waves to the outer discharge section and the inner discharge section, Equipped with, The waveguide section includes a resonator having a waveguide, The aforementioned resonator is, 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 inner slots are arranged along the second end and circumferentially around the central axis above the inner emission portion, and electromagnetically coupling the waveguide and the inner emission portion to each other, 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, including, Plasma processing equipment.

[0074] [E2] The plasma processing apparatus according to E1, wherein the plurality of inner slots and the plurality of outer slots are arranged alternately along the circumferential direction.

[0075] [E3] The plasma apparatus according to E1 or E2, wherein the resonator further includes a plurality of modification mechanisms configured to change the length of each of the plurality of inner slots and / or the plurality of outer slots along the circumferential direction.

[0076] [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 inner slots and / or 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 E3, including the one described above.

[0077] [E5] The plasma apparatus according to E1 or E2, wherein the resonator further includes a plurality of short-circuiting mechanisms configured to releasably short-circuit a plurality of portions that are the circumferential centers of each of the plurality of inner slots and / or the plurality of outer slots, or a plurality of portions of the waveguide along the centers, to ground.

[0078] [E6] Each of the above-mentioned multiple short-circuit mechanisms is A metal rod extending across corresponding parts among the aforementioned multiple parts, A switching circuit configured to releasably short-circuit the metal rod to the ground, A plasma processing apparatus as described in E5, including the one described above.

[0079] [E7] The aforementioned switching circuit is A diode including a cathode and an anode connected to the rod, A first switching transistor connected to the cathode, A current source connected between the first switching transistor and ground, A second switching transistor connected to the cathode is connected in parallel with the first switching transistor, A voltage source connected between the second switching transistor and ground, A signal generation circuit that alternately sets the first switching transistor and the second switching transistor to a closed state, Includes, The current value of the current source is set to a value greater than the amplitude of the high-frequency current of the electromagnetic wave flowing through the rod when the rod is short-circuited to ground in the corresponding portion. The voltage value of the voltage source is set to a value greater than the amplitude of the high-frequency voltage of the electromagnetic wave in the corresponding portion. Plasma processing apparatus as described in E6.

[0080] [E8] The plasma processing apparatus according to E6 or E7, wherein the plurality of short-circuit mechanisms are configured to switch between short-circuiting to ground and releasing the short-circuit in the plurality of parts with a period of 1 μs to 100 μs.

[0081] [E9] The plurality of outer slots include a plurality of first outer slots and a plurality of second outer slots arranged alternately along the circumferential direction. The aforementioned multiple parts are The central portion of the plurality of first outer slots in the circumferential direction, or a plurality of first portions arranged along the central portion of the plurality of first outer slots in the circumferential direction, The central portion of the plurality of second outer slots in the circumferential direction, or a plurality of second portions arranged along the central portion of the plurality of second outer slots in the circumferential direction, Includes, The aforementioned multiple short-circuit mechanisms are The short circuit of the plurality of first parts to ground is released, and the plurality of second parts are short-circuited to ground to form a first state. After the first state, a second state is formed in which the plurality of first parts are short-circuited to ground and the short-circuits to ground in the plurality of second parts are released. After the second state, a third state is formed in which the plurality of first parts and the plurality of second parts are short-circuited to ground. It is structured to repeat itself. A plasma processing apparatus as described in any one of items E5 to E7.

[0082] [E10] The plasma processing apparatus according to E9, wherein the plurality of short-circuit mechanisms are configured to switch between the first state, the second state, and the third state in sequence with a period of 1 μs to 100 μs.

[0083] [E11] 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 E1 to E10, including the one described above.

[0084] [E12] (a) In a plasma processing apparatus described in any one of E6 to E10, a step of supplying electromagnetic waves to a plurality of outer slots and a plurality of inner slots via the waveguide in order to supply electromagnetic waves to the plasma generation space, (b) A step of adjusting the amount of electromagnetic waves emitted from the plurality of inner slots and / or the plurality of outer slots by adjusting the plurality of short-circuit mechanisms to short-circuit and release the short-circuit of the plurality of parts to ground, A plasma generation method including [specific component].

[0085] [E13] The plasma generation method according to E12, wherein, in (b) above, the short-circuiting of the plurality of parts to ground and the release of the short-circuiting are switched at a period of 1 μs or more and 100 μs or less.

[0086] [E14] (a) In a plasma processing apparatus described in E9 or E10, the steps include supplying electromagnetic waves to a plurality of outer slots and a plurality of inner slots via a waveguide in order to supply electromagnetic waves to the plasma generation space, (b) A step of releasing the short circuit to ground in the plurality of first parts by the plurality of short-circuiting mechanisms and forming a first state in which the plurality of second parts are short-circuited to ground, (c) After (b) above, a step of forming a second state in which the plurality of first parts are short-circuited to ground by the plurality of short-circuiting mechanisms and the short-circuiting of the plurality of second parts to ground is released, (d) After (c), a step of forming a third state in which the plurality of first parts and the plurality of second parts are short-circuited to ground, (e) A step of repeating (b), (c), and (d) in order, A plasma generation method including [specific component].

[0087] [E15] The plasma generation method according to E14, wherein the first state, the second state, and the third state are switched sequentially with a period of 1 μs or more and 100 μs or less.

[0088] 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]

[0089] 1...Plasma processing device, 10...Chamber, 161...Outer discharge section, 162...Inner discharge section, 18...Waveguide section, 20...Resonator, 20w...Waveguide, 201...First end, 202...Second end, 20s1...Outer slot, 20s2...Inner slot, 20v...Changing mechanism, 50,50C...Short circuit mechanism.

Claims

1. A chamber including a plasma generation space, An outer emission section and an inner emission section are provided to extend circumferentially around the central axis of the chamber and the plasma generation space and to radiate electromagnetic waves from thereto into the plasma generation space, wherein the outer emission section extends radially with respect to the central axis outside the inner emission section, and the outer emission section and the inner emission section, A waveguide configured to supply the electromagnetic waves to the outer discharge section and the inner discharge section, Equipped with, The waveguide section includes a resonator having a waveguide, The aforementioned resonator is, 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 inner slots are arranged along the second end and circumferentially around the central axis above the inner emission portion, and electromagnetically coupling the waveguide and the inner emission portion to each other, 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. including, Plasma processing equipment.

2. The plasma processing apparatus according to claim 1, wherein the plurality of inner slots and the plurality of outer slots are arranged alternately along the circumferential direction.

3. The plasma apparatus according to claim 2, wherein the resonator further includes a plurality of modification mechanisms configured to change the length of each of the plurality of inner slots and / or the plurality of outer slots along the circumferential direction.

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 inner slots and / or 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 3, including the following:

5. The plasma apparatus according to claim 1, wherein the resonator further includes a plurality of short-circuiting mechanisms configured to releasably short-circuit a plurality of portions that are the circumferential centers of each of the plurality of inner slots and / or the plurality of outer slots, or a plurality of portions of the waveguide along the centers, to ground.

6. Each of the above-mentioned multiple short-circuit mechanisms is A metal rod extending across corresponding parts among the aforementioned multiple parts, A switching circuit configured to releasably short-circuit the metal rod to the ground, The plasma processing apparatus according to claim 5, including the following:

7. The aforementioned switching circuit is A diode including a cathode and an anode connected to the rod, A first switching transistor connected to the cathode, A current source connected between the first switching transistor and ground, A second switching transistor connected to the cathode is connected in parallel with the first switching transistor, A voltage source connected between the second switching transistor and ground, A signal generation circuit that alternately sets the first switching transistor and the second switching transistor to a closed state, Includes, The current value of the current source is set to a value greater than the amplitude of the high-frequency current of the electromagnetic wave flowing through the rod when the rod is short-circuited to ground in the corresponding portion. The voltage value of the voltage source is set to a value greater than the amplitude of the high-frequency voltage of the electromagnetic wave in the corresponding portion. The plasma processing apparatus according to claim 6.

8. The plasma processing apparatus according to claim 6, wherein the plurality of short-circuit mechanisms are configured to switch between short-circuiting to ground in the plurality of parts and releasing the short-circuit at a period of 1 μs to 100 μs.

9. The plurality of outer slots include a plurality of first outer slots and a plurality of second outer slots arranged alternately along the circumferential direction. The aforementioned multiple parts are The central portion of the plurality of first outer slots in the circumferential direction, or a plurality of first portions arranged along the central portion of the plurality of first outer slots in the circumferential direction, The central portion of the plurality of second outer slots in the circumferential direction, or a plurality of second portions arranged along the central portion of the plurality of second outer slots in the circumferential direction, Includes, The aforementioned multiple short-circuit mechanisms are The short circuit of the plurality of first parts to ground is released, and the plurality of second parts are short-circuited to ground to form a first state. After the first state, a second state is formed in which the plurality of first parts are short-circuited to ground and the short-circuits to ground in the plurality of second parts are released. After the second state, a third state is formed in which the plurality of first parts and the plurality of second parts are short-circuited to ground. It is structured to repeat itself. A plasma processing apparatus according to any one of claims 5 to 7.

10. The plasma processing apparatus according to claim 9, wherein the plurality of short-circuit mechanisms are configured to sequentially switch between the first state, the second state, and the third state with a period of 1 μs to 100 μs.

11. 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 1 to 8, including

12. (a) In the plasma processing apparatus according to claim 6, the steps of supplying electromagnetic waves to a plurality of outer slots and a plurality of inner slots via the waveguide in order to supply electromagnetic waves to the plasma generation space, (b) A step of adjusting the amount of electromagnetic waves emitted from the plurality of inner slots and / or the plurality of outer slots by adjusting the short-circuiting and release of the short-circuiting of the plurality of parts to ground using the plurality of short-circuiting mechanisms, A plasma generation method including [specific component].

13. The plasma generation method according to claim 12, wherein in (b) above, the short-circuiting of the plurality of parts to ground and the release of the short-circuiting are switched at a period of 1 μs to 100 μs.

14. (a) In the plasma processing apparatus according to claim 9, the steps of supplying electromagnetic waves to a plurality of outer slots and a plurality of inner slots via the waveguide in order to supply electromagnetic waves to the plasma generation space, (b) A step of releasing the short circuit to ground in the plurality of first parts by the plurality of short-circuiting mechanisms and forming a first state in which the plurality of second parts are short-circuited to ground, (c) After (b) above, a step of forming a second state in which the plurality of first parts are short-circuited to ground by the plurality of short-circuiting mechanisms and the short-circuiting of the plurality of second parts to ground is released, (d) After (c), a step of forming a third state in which the plurality of first parts and the plurality of second parts are short-circuited to ground, (e) A step of repeating (b), (c), and (d) in order, A plasma generation method including [specific component].

15. The plasma generation method according to claim 14, wherein the first state, the second state, and the third state are switched sequentially with a period of 1 μs or more and 100 μs or less.

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