Matching circuit and plasma processing apparatus

Abstract

To provide a technique capable of suppressing a relay switch, to which a radio-frequency current is supplied, from being unintentionally changed from a closed state to an open state thereof in a matching circuit of a plasma processing apparatus.SOLUTION: A disclosed matching circuit includes a plurality of reactance elements and a plurality of relays. The plurality of reactance elements are connected to a supply line for supplying radio-frequency power. Each of the plurality of relays includes a relay switch connected to a corresponding reactance element and the ground, and a relay coil. Each of the plurality of relays includes: at least one diode configured to rectify a radio-frequency current flowing through a parasitic capacitance between the relay coil and the corresponding reactance element; and at least one capacitor configured to generate a direct-current voltage applied to the relay coil in response to a current generated by rectifying the radio-frequency current with the at least one diode.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION An exemplary embodiment of the present disclosure relates to a matching circuit and a plasma processing apparatus. [Background technology]

[0002] A plasma processing apparatus is used in plasma processing of a substrate. The plasma processing apparatus includes a chamber, a high-frequency power supply, and a matching box. The high-frequency power supply is configured to generate high-frequency power so as to generate plasma from a gas in the chamber. The matching box is configured to match the impedance of a load to the output impedance of the high-frequency power supply. The matching box of the plasma processing apparatus described in Patent Document 1 listed below includes multiple capacitors and multiple switching elements, and is configured to adjust the variable capacitance of the matching box depending on the open or closed state of the multiple switching elements. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-78495 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique for suppressing an unintended change from a closed state to an open state of a relay switch to which a high-frequency current is supplied in a matching circuit of a plasma processing apparatus. [Means for solving the problem]

[0005] In one exemplary embodiment, a matching circuit is provided. The matching circuit includes a plurality of reactance elements and a plurality of relays. The plurality of reactance elements are connected to a supply line for high-frequency power for plasma generation. Each of the plurality of relays includes a relay switch and a relay coil. The relay switch has a first contact and a second contact. The first contact of the relay switch is connected to a corresponding one of the plurality of reactance elements. The second contact of the relay switch is connected to ground. Each of the plurality of relays includes at least one diode and at least one capacitor. The at least one diode is connected in parallel to the relay coil and configured to rectify a high-frequency current flowing through a parasitic capacitance between the relay coil and the corresponding reactance element. The at least one capacitor is connected in parallel to the relay coil. The at least one capacitor is configured to generate a DC voltage applied to the relay coil in response to a current generated by rectifying the high-frequency current by the at least one diode. [Effects of the Invention]

[0006] According to one exemplary embodiment, it is possible to suppress an unintended change from a closed state to an open state of a relay switch to which a high frequency current is supplied in a matching circuit of a plasma processing apparatus. [Brief explanation of the drawings]

[0007] [Figure 1] 1 illustrates a plasma processing apparatus according to an exemplary embodiment; [Figure 2] FIG. 2 illustrates a lower portion of a resonator of a plasma processing apparatus according to an exemplary embodiment. [Figure 3] FIG. 1 is a cross-sectional view of a coupler according to an exemplary embodiment. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Figure 5] FIG. 4 is a cross-sectional view taken along line VV in FIG. [Figure 6]1 is an admittance chart associated with a coupler according to one exemplary embodiment. [Figure 7] FIG. 2 illustrates a matching circuit according to an exemplary embodiment. [Figure 8] FIG. 10 illustrates a relay according to another exemplary embodiment. [Figure 9] FIG. 10 illustrates a relay according to yet another exemplary embodiment. [Figure 10] FIG. 10 is a cross-sectional view illustrating a coupler according to another exemplary embodiment. [Figure 11] FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. [Figure 12] FIG. 1 illustrates a plasma processing apparatus according to another exemplary embodiment. [Figure 13] FIG. 10 is a cross-sectional view illustrating a coupler according to yet another exemplary embodiment. [Figure 14] FIG. 14 is a cross-sectional view taken along line XIV-XIV in FIG. [Figure 15] FIG. 10 is a cross-sectional view illustrating a coupler according to yet another exemplary embodiment. [Figure 16] FIG. 16 is a cross-sectional view taken along line XVI-XVI in FIG. 15. [Figure 17] FIG. 10 is a cross-sectional view illustrating a coupler according to yet another exemplary embodiment. [Figure 18] FIG. 18 is a cross-sectional view taken along line XVIII-XVIII in FIG. 17. [Figure 19] 10 is a table illustrating the relationship between relay switch state (open or closed) and inductance for each of a plurality of relays in a coupler according to yet another exemplary embodiment. [Figure 20] 1A-1C illustrate example configurations for fault detection of multiple relays that may be employed in a combiner according to various exemplary embodiments. DETAILED DESCRIPTION OF THE INVENTION

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

[0009] 1 is a diagram showing a plasma processing apparatus according to an exemplary embodiment, which includes a chamber 10, a substrate support 12, an introduction section 16, a resonator 20, a high-frequency power supply 24, and a coupler 30.

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

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

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

[0013] In one embodiment, the plasma processing apparatus 1 may further include an upper electrode 14. The upper electrode 14 is provided above the substrate support 12 with a processing space 10s interposed therebetween. The upper electrode 14 is made of a conductor such as a metal (e.g., aluminum) and has a substantially disk shape. The central axis of the upper electrode 14 is an axis AX. The upper electrode 14, together with a shower plate 22 (described later), constitutes an excitation electrode.

[0014] The introduction part 16 is provided to emit electromagnetic waves from there into a plasma generation region. In the plasma processing apparatus 1, the plasma generation region is the space within the processing space 10s and directly below the excitation electrode, i.e., directly below the shower plate 22. In the plasma processing apparatus 1, the electromagnetic waves emitted from the introduction part 16 into the plasma generation region excite the gas in the plasma generation region to generate plasma. The electromagnetic waves emitted from the introduction part 16 into the plasma generation region may be high-frequency waves such as VHF waves or UHF waves. The introduction part 16 is formed from a dielectric material such as quartz, aluminum nitride, or aluminum oxide. In one embodiment, the introduction part 16 is provided at a lateral end of the processing space 10s and extends circumferentially around the axis AX. The introduction part 16 may have a ring shape.

[0015] The resonator 20 includes a power feeder 20p and a waveguide 20w. The power feeder 20p is an electromagnetic wave inlet for the waveguide 20w of the resonator 20. The electromagnetic wave is generated based on high-frequency power generated by a high-frequency power supply 24. The high-frequency power supply 24 is configured to be able to change the frequency of the high-frequency power it outputs. The electromagnetic wave is input to the power feeder 20p of the resonator 20 via a coupler 30, which will be described later. The resonator 20 resonates the electromagnetic wave input to the power feeder 20p within the waveguide 20w and propagates it to the introduction section 16. The electromagnetic wave is introduced from the introduction section 16 into the plasma generation region. In one embodiment, the resonator 20 may be provided above the chamber 10 and on the upper electrode 14.

[0016] In one embodiment, the plasma processing apparatus 1 may further include a shower plate 22. The shower plate 22 may be made of a metal such as aluminum. The inlet portion 16 extends to surround the shower plate 22. The inlet portion 16 and the shower plate 22 are arranged to close an opening at the upper end of the chamber 10. 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.

[0017] The shower plate 22 is provided below the upper electrode 14. The shower plate 22 extends above the plasma generation region. The shower plate 22 and the upper electrode 14 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 in the shower plate 22 are connected to the gas diffusion space 14d. The upper electrode 14 also 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 unit 26 is connected to the gas diffusion space 14d. Gas output from the gas supply unit 26 is supplied to the processing space 10s via the inlet 14h, the gas diffusion space 14d, and the plurality of gas holes 22h.

[0018] Hereinafter, reference will be made to FIG. 2 together with FIG. 1. FIG. 2 is a diagram illustrating the lower portion of a resonator of a plasma processing apparatus according to an exemplary embodiment. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1. 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 an aluminum alloy, copper, nickel, stainless steel, or the like, and may be coated with a low-resistivity material such as silver, gold, or rhodium.

[0019] 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 a waveguide 20w of the resonator 20. The second end 202 is electromagnetically coupled to the introduction portion 16.

[0020] In one embodiment, the wall of the resonator 20 may include an inner periphery 20i and an outer periphery 20o. The inner periphery 20i extends around a central axis AX and has a generally cylindrical shape. The outer periphery 20o extends coaxially with the inner periphery 20i around the axis AX. The outer periphery 20o may have a generally cylindrical shape.

[0021] The waveguide 20w may have a layer structure in which layers are alternately folded between the inner circumferential portion 20i and the outer circumferential portion 20o. The walls of the waveguide 20w may include multiple walls extending radially and circumferentially between adjacent layers of the layer structure and between the inner circumferential portion 20i and the outer circumferential portion 20o. The multiple walls may be annular plates.

[0022] The waveguide 20w may also include an upper portion 20a constituting the uppermost layer of the layer structure and a lower portion 20b constituting the lowermost layer of the layer structure. The layer structure may also include an intermediate portion 20c between the upper portion 20a and the lower portion 20b. In this embodiment, the upper portion 20a may provide a first end 201, i.e., an upper end, of the waveguide 20w at the outer periphery 20o. In this case, the first end 201 of the waveguide 20w extends along the circumferential direction around the axis AX. The lower portion 20b may also provide a second end 202, i.e., a lower end, of the waveguide 20w at the outer periphery 20o. In this case, the second end 202 of the waveguide 20w extends along the circumferential direction around the axis AX.

[0023] The resonator 20 provides a plurality of gaps 20g near or along the second end 202. The plurality of gaps 20g are arranged in the circumferential direction around the axis AX. Electromagnetic waves that resonate in the resonator 20 electromagnetically propagate to the introduction portion 16 through the plurality of gaps 20g.

[0024] In one embodiment, the upper electrode 14 provides a plurality of slots 14s as the plurality of gaps 20g and includes a plurality of beams 14b. The plurality of slots 14s are arranged above the lead-in portion 16. The plurality of slots 14s penetrate the upper electrode 14 along its thickness direction (vertical direction) and extend long in the circumferential direction. The plurality of slots 14s are spaced apart from one another and arranged along the circumferential direction around the axis line AX. The plurality of slots 14s may be arranged at equal intervals. The plurality of beams 14b are arranged alternately with the plurality of slots 14s along the circumferential direction around the axis line AX. The plurality of beams 14b connect the inner portion and the outer portion of the upper electrode 14 to each other.

[0025] In the plasma processing apparatus 1, electromagnetic waves resonate between the first end 201 and the second end 202. The electromagnetic waves resonating in the resonator 20 are supplied to the introduction portion 16 through the plurality of gaps 20g, i.e., the plurality of slots 14s. The electromagnetic waves supplied to the introduction portion 16 are emitted from the introduction portion 16 into a plasma generation region.

[0026] In the resonator 20, the distance d in the circumferential direction of each of the plurality of gaps 20g may satisfy the following formula (F1). 0.05λ g <d<0.3λ g …(F1) In formula (F1), λ g is the wavelength of the electromagnetic wave in the waveguide 20w. When formula (F1) is satisfied, the resonator 20 can supply a part of the electromagnetic wave propagating through the waveguide 20w to the introduction section 16, and can have an appropriately large reflection coefficient of the electromagnetic wave at the other end of the resonator 20.

[0027] The resonator length L of the resonator 20 between the first end 201 and the second end 202 is 20 (the distance between the first end 201 and the second end 202 along the waveguide 20w) may satisfy the following formula. (n-0.2)λ g / 2 <L 20 <nλ g / 2 …(F2) In formula (F2), λ g is the wavelength of the electromagnetic wave in the waveguide 20w. n is an integer equal to or greater than 1. The reactance in the gaps 20g is inductive. Therefore, the resonator length L 20 is set to nλ so as to satisfy equation (F2). g It can be set to a value slightly less than / 2.

[0028] The coupler 30 is connected between the high-frequency power supply 24 and the resonator 20. The coupler 30 includes an input port 30i, an output port 30o, and a supply line 31. The supply line 31 extends to connect the input port 30i and the output port 30o to each other. The high-frequency power supply 24 is connected to the input port 30i. The output port 30o is connected to the power supply 20p via a supply line 42. That is, the supply line 42 connects the output port 30o and the power supply 20p to each other.

[0029] In the plasma processing apparatus 1, the supply line 31 and the supply line 42 constitute a supply line 40. The supply line 40 is a distributed constant line extending from the input portion 30i through the coupler 30 to the power supply portion 20p, and is a transmission line having a constant characteristic impedance. The constant characteristic impedance is, for example, 50 Ω. The constant characteristic impedance may be 50 Ω or less. In one embodiment, the supply line 31 in the coupler 30 may be configured as a microstrip line. The supply line 42 may be configured as a coaxial line.

[0030] The coupler 30 may further include a matching circuit 34. The matching circuit 34 is disposed in a grounded housing 30h (e.g., a metal housing). The matching circuit 34 includes a variable reactance section 36 having a variable impedance. The variable reactance section 36 is connected between the connection point 30s of the supply line 31 and ground. The variable reactance section 36 includes a capacitor 50 and / or an inductor 60. The matching circuit 34 further includes a drive circuit 34d and a control circuit 34c. The drive circuit 34d is configured with a circuit for changing the impedance of the variable reactance section 36. The control circuit 34c is configured to control the drive circuit 34d. The control circuit 34c may be configured with a programmable processor such as a CPU or MPU, a programmable logic device such as an FPGA (Field Programmable Gate Array), or a dedicated circuit such as an ASIC (Application Specific Integrated Circuit).

[0031] In the plasma processing apparatus 1, the voltage V in the supply line 40 when there is no reflection from the load m0 is (2×Z0×P) 1 / 2 where Z0 is the characteristic impedance of the supply line 40, and P is the incident power to the supply line 40. When the characteristic impedance Z0 of the supply line 40 is 50 Ω and the incident power P is 1 kW, the voltage V m0 Even if total reflection occurs, the maximum voltage on the supply line 40 is V m0This is twice as large as the voltage difference between the supply line 31 and the coupler 30. Therefore, even if total reflection occurs, the plasma processing apparatus 1 can suppress the maximum voltage in the coupler 30 caused by the high-frequency power transmitted through the coupler 30. Furthermore, in the plasma processing apparatus 1, the variable reactance unit 36 ​​is connected to the supply line 31 included in the supply line 40. Therefore, an element having a relatively small withstand voltage can be used as an element constituting the variable reactance unit 36. As a result, the plasma processing apparatus 1 can reduce the size of the coupler 30. Furthermore, an element having a fast response speed can be used as an element in the matching circuit 34.

[0032] In one embodiment, the plasma processing apparatus 1 may further include a directional coupler and a power supply control unit 24c. The directional coupler may be provided within the high-frequency power supply 24 or between the high-frequency power supply 24 and the input unit 30i. The power supply control unit 24c may be configured from a programmable processor such as a CPU or an MPU, a programmable logic device such as an FPGA (Field Programmable Gate Array), or a dedicated circuit such as an ASIC (Application Specific Integrated Circuit).

[0033] The directional coupler outputs a signal reflecting the power level of the reflected wave of the high-frequency power to the power supply control unit 24c. The power supply control unit 24c controls the high-frequency power supply 24 or the matching circuit 34 in accordance with the signal from the directional coupler so as to reduce the power level of the reflected wave. The power supply control unit 24c may control the high-frequency power supply 24 to adjust the frequency of the high-frequency power in order to reduce the power level of the reflected wave. Alternatively, or in addition, the power supply control unit 24c may communicate with the control circuit 34c to cause the matching circuit 34 to adjust the reactance of the variable reactance unit 36 ​​in order to reduce the power level of the reflected wave.

[0034] 3 to 5 will be referred to below in addition to FIG. 1. FIG. 3 is a cross-sectional view showing a coupler according to one exemplary embodiment. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. FIG. 5 is a cross-sectional view taken along line VV in FIG. 3. Note that FIG. 3 shows the structure of a coupler according to yet another exemplary embodiment in a longitudinal cross section taken along line III-III in FIG. 4. The coupler 30A shown in FIGS. 3 to 5 can be used as the coupler 30 of the plasma processing apparatus 1.

[0035] The coupler 30A includes a transmission line plate 313 and a dielectric member 312 made of a metal such as copper. The transmission line plate 313 extends horizontally along its longitudinal direction to connect the input section 30i and the output section 30o to each other. The dielectric member 312 is disposed between the transmission line plate 313 and the bottom of the housing 30h. The transmission line plate 313 constitutes the feed line 31, and together with the dielectric member 312 and the bottom of the housing 30h, constitutes a microstrip line. The microstrip line has the constant characteristic impedance described above. Note that the dielectric member 312 does not necessarily have to be disposed in the region between the transmission line plate 313 and the bottom of the housing 30h. The region between the transmission line plate 313 and the bottom of the housing 30h may be filled with, for example, air.

[0036] In plasma processing apparatus 1 including coupler 30A, power supply 20p is arranged so that the distance r50 from axis AX to power supply 20p in the radial direction is such that the impedance on the load side from power supply 20p is 50Ω under desired plasma excitation conditions (center conditions) including the frequency of the high-frequency power, etc. In coupler 30A, variable reactance unit 36 ​​has capacitor 51 as capacitor 50 and includes inductor 61 as inductor 60.

[0037] The capacitor 51 has a plurality of capacitor elements 511. The plurality of capacitor elements 511 are a plurality of reactance elements. The plurality of capacitor elements 511 are connected to the supply line 40. Specifically, the plurality of capacitor elements 511 are connected to the supply line 31. To provide the plurality of capacitor elements 511, the capacitor 51 includes a capacitor plate 511p, a plurality of dielectric members 511d, and a plurality of capacitor patterns 511e on the printed circuit board 511b.

[0038] The capacitor plate 511p is made of a metal such as copper and extends horizontally above the transmission line plate 313. The transmission line plate 313, i.e., the transmission line, includes a connection point 30s. The connection point 30s is located between the input section 30i and the output section 30o. The capacitor plate 511p is connected to the connection point 30s via a metal support 30sp (connection member). The metal support 30sp extends upward from the connection point 30s.

[0039] The printed circuit board 511b extends horizontally above the capacitor plate 511p. The plurality of capacitor patterns 511e are formed on the rear surface (bottom surface) of the printed circuit board 511b so as to face the capacitor plate 511p. Each of the plurality of capacitor patterns 511e may have a substantially circular shape. The plurality of capacitor patterns 511e may be arranged along the longitudinal direction of the capacitor plate 511p. In the illustrated example, the plurality of capacitor patterns 511e are arranged to form two rows extending in a direction parallel to the longitudinal direction of the capacitor plate 511p. The printed circuit board 511b may have a slit 511bh penetrating the printed circuit board 511b in its thickness direction. The slit 511bh may be formed between the two rows of the plurality of capacitor patterns 511e. The slit 511bh can reduce the parasitic capacitance of the printed circuit board 511b.

[0040] Each of the plurality of dielectric members 511d is clamped between a corresponding one of the plurality of capacitor patterns 511e and a capacitor plate 511p using a screw. The plurality of dielectric members 511d may be formed from polytetrafluoroethylene or the like and may have a ring shape. The edge of each of the plurality of capacitor patterns 511e has a size slightly smaller than that of the plurality of dielectric members 511d so that the edge is positioned more inward than the edge of the corresponding one of the plurality of dielectric members 511d. This can suppress creeping discharge.

[0041] In the capacitor 51, each of the plurality of capacitor elements 511 includes a corresponding capacitor pattern among the plurality of capacitor patterns 511e and a corresponding dielectric member among the plurality of dielectric members 511d. The plurality of capacitor elements 511 share a capacitor plate 511p. The plurality of capacitor patterns 511e may have the same area. In this case, the plurality of capacitor elements 511 have the same capacitance. In another embodiment, the plurality of capacitor elements 511 may have different capacitances.

[0042] The matching circuit 34 of the coupler 30A further includes a plurality of relays 71. Each of the plurality of relays 71 includes a relay switch 71s and a relay coil 71c. The relay switch 71s includes a first contact 71t1 and a second contact 71t2 (see FIG. 7, etc.), and can switch between disconnection and connection between the first contact 71t1 and the second contact 71t2 depending on its state (open or closed). The plurality of relays 71 are provided on a printed circuit board 511b. The first contact of the relay switch of each of the plurality of relays 71 is connected to a corresponding one of the plurality of capacitor patterns 511e. The second contact of the relay switch of each of the plurality of relays 71 is connected to a ground pattern 511g provided on the back surface of the printed circuit board 511b. The ground pattern 511g is connected to the bottom of the housing 30h, i.e., to ground, via a plurality of metal supports 51sp.

[0043] In the coupler 30A, the drive circuit 34d is connected to the relay coils 71c of the multiple relays 71 via the connectors 51cn. The drive circuit 34d is configured to apply a DC voltage signal to the relay coils 71c of the multiple relays 71 to set the state (open or closed) of the relay switches 71s of the multiple relays 71. The control circuit 34c can communicate with the power supply control unit 24c via the communication circuit 34t. The control circuit 34c receives notification from the power supply control unit 24c via the communication circuit 34t of the capacitance setting value of the capacitor 51 for reducing the power level of the reflected wave. The control circuit 34c controls the drive circuit 34d to set the state of the relay switches 71s of the multiple relays 71 to the notified setting value. In the coupler 30A, the capacitance of the capacitor 51 can be adjusted by adjusting the state of the relay switches 71s of the multiple relays 71.

[0044] In the coupler 30A, the plurality of capacitor elements 511 are arranged in one or more rows. However, the plurality of capacitor elements 511 may be arranged in the circumferential direction around an axis extending vertically from the connection point 30s. The plurality of capacitor elements 511 may be arranged at equal intervals. Furthermore, the plurality of relays 71 may be arranged in the circumferential direction radially outward of the plurality of capacitor elements 511.

[0045] In addition, in the coupler 30A, the matching circuit 34 includes an inductor 61 as the inductor 60. The inductor 61 is configured from an inductor plate, which is a conductive plate made of a metal such as copper. The inductor plate extends horizontally above the printed circuit board 511b. The inductor plate is connected to the connection point 30s via a metal support 30sp.

[0046] A pair of holes 30th are formed in a pair of side walls of the housing 30h. The pairs of holes 30th are arranged in the vertical direction. Both ends of the inductor plate are fixed to the pair of side walls of the housing 30h using a pair of screws and a pair of nuts inserted into a pair of holes 30th selected from the pairs of holes 30th. In the coupler 30A, the electrical length between the inductor plate and the connection point 30s can be changed by changing the pair of holes 30th selected from the pairs of holes 30th. This makes it possible to change the inductance of the inductor 61.

[0047] The inductance L of the inductor 61 is ωL=1 / (ωC h ) is set to satisfy the following: where ω is the plasma excitation angular frequency. Also, C h is the median value of the variable range of the capacitance of the capacitor 51.

[0048] Further reference is now made to FIG. 6 , which is an admittance chart associated with a coupler according to an exemplary embodiment. In FIG. 6 , “f increase” and “f decrease” represent the direction of change in the load-side impedance of the connection point 30s and the corresponding reflection coefficient when the frequency of the high-frequency power is increased or decreased. Also in FIG. 6 , “L added” and “C added” represent the direction of change in the load-side impedance of the connection point 30s and the corresponding reflection coefficient when the reactance of the variable reactance unit 36 ​​is changed. Specifically, “L added” represents the change in the load-side impedance and reflection coefficient of the connection point 30s when the inductance of the variable reactance unit 36 ​​is increased. Also, “C added” represents the change in the load-side impedance and reflection coefficient of the connection point 30s when the capacitance of the variable reactance unit 36 ​​is increased.

[0049] In the plasma processing apparatus 1, the position of the connection point 30s may be set to satisfy the orthogonal condition. That is, the position of the connection point 30s may be determined so that the change in the reflection coefficient corresponding to the load-side impedance of the connection point 30s when the reactance of the variable reactance unit 36 ​​is changed (see the arrows on the isoconductance curves in FIG. 6 ) and the change in the reflection coefficient when the frequency of the high-frequency power generated by the high-frequency power supply 24 is changed (see the arrows on the thick solid lines in FIG. 6 ) satisfy the orthogonal condition in a coordinate system having real and imaginary axes that are orthogonal to each other, as shown in FIG. 6 .

[0050] When the orthogonal condition is satisfied, it is possible to increase the range in which the impedance can be changed in the plasma processing apparatus 1. Furthermore, the load impedance change due to the change in reactance in the variable reactance unit 36 ​​and the load impedance change due to the change in the frequency of the high frequency power generated by the high frequency power supply 24 become more independent from each other. This makes it easier to match the impedance.

[0051] Specific conditions for satisfying the orthogonal condition will be described below with further reference to Fig. 6. When the orthogonal condition is satisfied, the impedance on the load side of connection point 30s changes along the thick solid line in Fig. 6 when the frequency of the high frequency power generated by high frequency power supply 24 is changed. Furthermore, when the frequency of the high frequency power generated by high frequency power supply 24 is changed, the impedance viewed from power supply 20p on the load side changes along the dashed circle in Fig. 6. In Fig. 6, in order for the angle formed by the line extending from the center point on the real axis (the point indicating 50 Ω) through the center of the thick solid circle to be 90 degrees, the angle θ formed by the dashed line extending from the center point on the real axis (the point indicating 50 Ω) through the center of the dashed circle with the real axis in Fig. 6 must be 90 degrees. r and the angle θ, which is the difference between 90 degrees e The position of connection point 30s relative to feed portion 20p must be set so as to provide:

[0052] Here, the angle θ r is 4π×L r / λ grand the angle θ e is 4π×L e / λ ge In addition, L r is the length along the radial direction between the power feeding portion 20p and the upper end (first end 201) of the resonator 20. gr is the wavelength of the electromagnetic wave in the waveguide 20w of the resonator 20 between the power feeding portion 20p and the upper end (first end 201) of the resonator 20. e λ is the length between the feed point 20p and the connection point 30s. ge is the wavelength of the electromagnetic wave between the power supply 20p and the connection point 30s. r and angle θ e The orthogonal condition is satisfied if the sum of these is (2n+1) times 90 degrees. Therefore, the orthogonal condition is satisfied when the following equation (1) is satisfied, where n is 0 or a positive integer.

number

[0053] Reference will now be made to FIG. 7, which is a diagram illustrating a matching circuit according to an exemplary embodiment. The matching circuit 34 illustrated in FIG. 7 may be employed as the matching circuit 34 of the plasma processing apparatus 1. In the matching circuit 34 illustrated in FIG. 7, the drive circuit 34d includes a plurality of drive circuits 71d. Each of the plurality of drive circuits 71d may be provided as an element of a plurality of relays 71.

[0054] In each of the relays 71, the drive circuit 71d is configured to apply the DC voltage signal to the relay coil 71c when the relay switch 71s is set to a closed state under the control of the control circuit 34c. The drive circuit 71d may include, for example, a buffer transistor. As shown in FIG. 7, a choke coil 71 is provided between the drive circuit 71d and one end of the relay coil 71c. Lc may be connected to the drive circuit 71d, thereby suppressing the inflow of high-frequency current into the drive circuit 71d.

[0055] As shown in FIG. 7, in the matching circuit 34, each of the plurality of relays 71 is connected to a diode 71. D and capacitor 71 Cw Contains 71 diodes D and capacitor 71 Cw is connected in parallel to the relay coil 71c.

[0056] Diode 71 D The cathode of the diode 71 is connected to one end (the positive end) of the relay coil 71c. D The anode of the diode 71 is connected to ground. D is the parasitic capacitance 71 between the relay coil 71c and the corresponding capacitor element 511. Cp The high frequency current is rectified by the rectifier.

[0057] Capacitor 71 Cw Diode 71 D The relay switch 71s is configured to generate a DC voltage to be applied to the relay coil 71c in response to a current generated by rectifying a high frequency current by the capacitor 71. The relay switch 71s has a characteristic of transitioning from a closed state to an open state when the DC voltage applied to the relay coil 71c drops to a voltage level equal to or lower than a threshold voltage level. Cw The capacitance of the capacitor is Cw is set so that the DC voltage generated by the relay switch 71s has a voltage level higher than the threshold voltage level of the relay switch 71s.

[0058] In each of the plurality of relays 71, the high frequency voltage applied to the capacitor element 511 is converted into a parasitic capacitance 71 Cp and Capacitor 71 Cw The voltage is divided by diode 71 D is rectified by the capacitor 71 Cw A DC voltage is generated across the capacitor 71. Cw Since the voltage level of the DC voltage generated between both ends of is higher than the threshold voltage level, an unintended change of the relay switch 71s from the closed state to the open state due to noise or the like is suppressed.

[0059] Reference will now be made to Fig. 8, which is a diagram illustrating a relay according to another exemplary embodiment. The relay 71 illustrated in Fig. 8 can be employed as each of the multiple relays 71 of the matching circuit 34. The relay 71 illustrated in Fig. 8 will be described below in terms of differences from the relay 71 illustrated in Fig. 7.

[0060] 8, the relay coil 71c is floating from the ground with respect to high frequencies. T1 and a DC voltage generating circuit 71g. Tr and a pulse generator 71p.

[0061] In the relay 71 shown in FIG. T1 The transformer 71 is provided to prevent high frequency noise from being transmitted to the control circuit 34c and the drive circuit 34d. T1 The transformer 71 may have a magnetic core made of ferrite material. T1 Primary coil 71 C1 A DC power supply is connected to one end of the primary coil 71, and a voltage Vdd is applied to the primary coil 71. C1 A transistor 71 is connected between the other end of Tr The pulse generator 71p generates a high frequency pulse to drive the transistor 71 Tr A high frequency pulse is supplied to the control terminal of the transistor 71. The frequency of the high frequency pulse is, for example, 160 kHz. Tr When a high frequency pulse is applied to the transformer 71 T1 Secondary coil 71 C2 A pulse current is generated in the

[0062] The DC voltage generating circuit 71g includes a relay coil 71c and a transformer 71 T1 Secondary coil 71 C2 The DC voltage generating circuit 71g is connected between the capacitor 71 Cw , first diode 71 D1 , and the second diode 71 D2Secondary coil 71 C2 One end of the second diode 71 D2 The second diode 71 is connected to one end of the relay coil 71c via the D2 The anode of the secondary coil 71 C2 and a second diode 71 D2 The cathode of this is connected to one end of the relay coil 71c.

[0063] Capacitor 71 Cw and the first diode 71 D1 The relay coil 71c and the secondary coil 71 C2 The first diode 71 is connected in parallel between the first diode 71 and the second diode 72. D1 The cathode of the relay coil 71c is connected to one end of the second diode 71c. D2 The cathode of the first diode 71 is connected to the cathode of the first diode 71. D1 The anode of the relay coil 71c is connected to the other end of the secondary coil 71 C2 is connected to the other end of the

[0064] Secondary coil 71 C2 The pulse current generated in the second diode 71 D2 via capacitor 71 Cw When the high frequency pulse is in the OFF state, a return current generated by the inductance component of the relay coil 71c flows through the first diode 71. D1 This causes the current to flow through capacitor 71 Cw A DC voltage is generated at the relay coil 71c, and a DC voltage signal is applied to the relay coil 71c, causing the relay switch 71s to be set to a closed state.

[0065] In the relay 71 shown in FIG. 8, the high frequency voltage applied to the capacitor element 511 is applied to the parasitic capacitance 71 Cp and Capacitor 71 Cw The voltage is divided by capacitor 71 Cw A DC voltage is generated across the capacitor 71. CwSince the voltage level of the DC voltage generated between both ends of is higher than the threshold voltage level, an unintended change of the relay switch 71s from the closed state to the open state due to noise or the like is suppressed.

[0066] Reference will now be made to Fig. 9, which is a diagram illustrating a relay according to yet another exemplary embodiment. The relay 71 illustrated in Fig. 9 can be employed as each of the multiple relays 71 of the matching circuit 34. The relay 71 illustrated in Fig. 9 will be described below in terms of differences from the relay 71 illustrated in Fig. 7.

[0067] 9, the relay coil 71c is floating from the ground with respect to high frequencies. T1 and a DC voltage generating circuit 71g. The driving circuit 71d includes a first transistor 71 Tr1 , second transistor 71 Tr2 , and a pulse generator 71p.

[0068] In the relay 71 shown in FIG. T1 The transformer 71 is provided to prevent high frequency noise from being transmitted to the control circuit 34c and the drive circuit 34d. T1 The transformer 71 may have a magnetic core made of ferrite material. T1 Primary coil 71 C1 A second transistor 71 is connected between one end of the Tr2 is connected to the primary coil 71 C1 A first transistor 71 is connected between the other end of the Tr1 The pulse generator 71p is connected to the first transistor 71 Tr1 and the second transistor 71 Tr2 A high frequency pulse for switching the first transistor 71 in opposite phase is applied to the second transistor 72. Tr1 and the second transistor 71 Tr2 The frequency of the high frequency pulse is, for example, 160 kHz. Tr1 and the second transistor 71Tr2 When a high frequency pulse is applied to each control terminal, the transformer 71 T1 Secondary coil 71 C2 A pulse current is generated in the

[0069] In the relay 71 shown in FIG. 9, a DC voltage generating circuit 71g is connected between a relay coil 71c and a secondary coil 71 C2 The DC voltage generating circuit 71g is connected between the first capacitor 71 Cw1 , second capacitor 71 Cw2 , first diode 71 D1 , and the second diode 71 D2 The first capacitor 71 Cw1 One end of the second capacitor 71 is connected to one end of the relay coil 71c. Cw2 One end of the first capacitor 71 Cw1 the other end of the secondary coil 71 C2 The first capacitor 71 is connected to one end of the Cw1 and the other end of the second capacitor 71 Cw2 and one end of the secondary coil 71 C2 Between one end of the inductor 71 Li may be connected to the inductor 71. Li is the parasitic capacitance 71 Cp The high frequency current flowing through the transformer 71 is blocked or attenuated. T1 The magnetic saturation of the magnetic flux is suppressed.

[0070] First diode 71 D1 The anode of the relay coil 71c is connected to the other end of the second capacitor 71c. Cw2 The first diode 71 is connected to the other end of each of the first and second diodes 71 and 72. D1 The cathode of the secondary coil 71 C2 The other end of the second diode 71 is connected to the D2 The anode of the first diode 71 D1 Cathode and secondary coil 71 C2 The other end of the second diode 71 is connected to the D2The cathode of the relay coil 71c is connected to one end of the first capacitor 71c. Cw1 is connected to one end of the

[0071] Secondary coil 71 C2 The pulse current generated in the first diode 71 D1 and the second diode 71 D2 and the first capacitor 71 Cw1 and the second capacitor 71 Cw2 This charges the first capacitor 71 Cw1 and the second capacitor 71 Cw2 A DC voltage is generated across the series connection, and a DC voltage signal is applied to the relay coil 71c, causing the relay switch 71s to be set to a closed state.

[0072] In the relay 71 shown in FIG. 9, a high frequency voltage applied to the capacitor element 511 is applied to the parasitic capacitance 71 Cp and the first capacitor 71 Cw1 and the second capacitor 71 Cw2 As a result, the voltage is divided by the first capacitor 71 Cw1 and the second capacitor 71 Cw2 A DC voltage is generated across the series connection of the first capacitor 71. Cw1 and the second capacitor 71 Cw2 Since the voltage level of the DC voltage generated across the series connection is higher than the threshold voltage level, an unintended change of the relay switch 71s from the closed state to the open state due to noise or the like is suppressed.

[0073] Hereinafter, a coupler according to another exemplary embodiment will be described with reference to FIGS. 10 and 11. FIG. 10 is a cross-sectional view showing a coupler according to another exemplary embodiment. FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. 10. FIG. 11 shows the structure of a longitudinal cross section of a coupler according to an exemplary embodiment. A coupler 30B shown in FIGS. 10 and 11 can be used as the coupler 30 of a plasma processing apparatus 1. Hereinafter, the coupler 30B will be described from the perspective of differences from the coupler 30A.

[0074] The coupler 30B includes a printed circuit board 311. The printed circuit board 311 may be made of a material having a small dielectric loss tangent. For example, the printed circuit board 311 may be made of a glass epoxy material having an inorganic material dispersed therein. The printed circuit board 311 is provided within a housing 30h.

[0075] The coupler 30B includes a transmission line pattern 311t and an inductor pattern 311i. The transmission line pattern 311t and the inductor pattern 311i are formed on the back surface of the printed circuit board 311. The transmission line pattern 311t extends in its longitudinal direction from the input section 30i to the connection point to the supply line 42. In the coupler 30B, the transmission line pattern 311t and the bottom of the housing 30h form the supply line 31, i.e., the above-mentioned transmission line. This transmission line also has the above-mentioned constant characteristic impedance.

[0076] The coupler 30B includes a capacitor 52 as the capacitor 50 of the variable reactance section 36. The capacitor 52 is formed of a plurality of capacitor elements. The number M of capacitor elements in the capacitor 52 may be any number equal to or greater than two.

[0077] The capacitor 52 includes a capacitor pattern 52g and capacitor patterns 52a1 to 52a5. The capacitor pattern 52g is formed on the back surface of the printed circuit board 311. The capacitor pattern 52g is connected to the connection point 30s. The capacitor patterns 52a1 to 52a5 are formed on the top surface of the printed circuit board 311 so as to face the capacitor pattern 52g with the printed circuit board 311 (dielectric member) interposed therebetween.

[0078] Each of the capacitor patterns 52a1-52a5, together with the printed circuit board 311 and the capacitor pattern 52g, forms a plurality of capacitor elements. That is, the plurality of capacitor elements include the capacitor patterns 52a1-52a5 as their respective first electrodes. The plurality of capacitor elements include the capacitor pattern 52g as their respective common second electrodes. Furthermore, the plurality of capacitor elements include the printed circuit board 311 as their respective common dielectric member.

[0079] In the capacitor 52, the capacitor pattern 52g may provide a plurality of slits, each of which extends between two adjacent capacitor elements to suppress interference between the capacitor elements.

[0080] The capacitor patterns 52a1 to 52a5 may have different areas so that the capacitor elements have different capacitances. The capacitance, i.e., the electrostatic capacity, of each of the capacitor elements of the capacitor 52 is expressed as C m =0.5×C m-1 where C m is the capacitance of the m-th capacitor element among the first to M-th capacitor elements, which are the plurality of capacitor elements. The capacitances of the plurality of capacitor elements are, for example, 12.8 pF, 6.4 pF, 3.2 pF, 1.6 pF, and 0.8 pF, respectively.

[0081] In the coupler 30B, the matching circuit 34 further includes a plurality of relays 71. In the coupler 30B, the plurality of relays 71 have the configurations shown in any of FIGS. 7 to 9 to switch between disconnection and connection between each of the plurality of capacitor elements of the coupler 30B and ground. The plurality of relays 71 may be mounted on the upper surface of the printed circuit board 311. Each of the plurality of relays 71 includes a relay switch 71s and a relay coil 71c. The relay switch 71s includes a first contact 71t1 and a second contact 71t2, and can switch between disconnection and connection between the first contact 71t1 and the second contact 71t2 depending on the state (open or closed) of the relay switch 71s. The first contact 71t1 of the relay switch 71s of each of the plurality of relays 71 is connected to a corresponding one of the capacitor patterns 52a1 to 52a5. The second contact 71t2 of each relay switch 71s of the plurality of relays 71 is connected to a ground pattern 311g provided on the rear surface of the printed circuit board 311. The ground pattern 311g is connected to the bottom of the housing 30h, i.e., to the ground, via a plurality of short-circuit members 52sp (for example, metal posts).

[0082] In the coupler 30B, the drive circuit 34d is configured to apply a DC voltage signal to the relay coils 71c of each of the plurality of relays 71 to set the state (open or closed) of the relay switch 71s of each of the plurality of relays 71. The control circuit 34c is capable of communicating with the power supply control unit 24c via the communication circuit 34t. The control circuit 34c is notified via the communication circuit 34t of the setting value of the capacitance of the capacitor 52, which is used to reduce the power level of the reflected wave. The control circuit 34c controls the drive circuit 34d to set the state of the relay switch 71s of each of the plurality of relays 71 to the notified setting value.

[0083] In the coupler 30B, the capacitance of the capacitor 52 can be adjusted by setting the state of the relay switch 71s of each of the multiple relays 71. In one embodiment, the capacitance of the capacitor 52 can be changed in 32 binary steps.

[0084] In the coupler 30B, the inductor pattern 311i forms an inductor 62 as the inductor 60 of the variable reactance unit 36. The inductor pattern 311i is configured so that the length (electrical length) from one end to the portion shorted to ground can be changed. The printed circuit board 311 is formed with a plurality of holes 311h penetrating the printed circuit board 311 in its thickness direction, aligned between one end and the other end of the inductor pattern 311i. The inductor pattern 311i is shorted to ground by threading a screw inserted into a selected one of the plurality of holes 311h into a screw hole in a short-circuiting member 62sp (e.g., a metal support) sandwiched between the inductor pattern 311i and the bottom of the housing 30h. The length of the inductor 62 from one end of the inductor pattern 311i to the portion shorted to ground can be changed by changing the selected hole from the plurality of holes 311h. This allows the inductance of the inductor 62 to be changed.

[0085] The inductance L of the inductor 62 is ωL=1 / (ωC h ) is set to satisfy the following: where ω is the plasma excitation angular frequency. Also, C h is the median value of the variable range of the capacitance of the capacitor 52.

[0086] Hereinafter, still another exemplary embodiment will be described with reference to FIGS. 12 to 14. FIG. 12 is a diagram showing a plasma processing apparatus according to another exemplary embodiment. FIG. 13 is a cross-sectional view showing a coupler according to still another exemplary embodiment. FIG. 14 is a cross-sectional view taken along line XIV-XIV in FIG. 13. Note that FIG. 13 shows the structure of a longitudinal cross section of a coupler according to still another exemplary embodiment. Hereinafter, the plasma processing apparatus 1C shown in FIG. 12 will be described from the perspective of differences from the plasma processing apparatus 1. Furthermore, the coupler 30C of the plasma processing apparatus 1C will be described from the perspective of differences from the coupler 30A.

[0087] In the plasma processing apparatus 1C, the supply line 40 is configured as a metal coupling rod. The supply line 40 extends upward from the power supply 20p to the input 30i. In the plasma processing apparatus 1C, the power supply 20p may be located at a radially outer position where the impedance on the load side from the power supply 20p is 50Ω under desired plasma excitation conditions (center conditions) including the frequency of the high-frequency power. In other words, the radial distance from the axis AX to the power supply 20p may be longer than the above-mentioned r50.

[0088] In the coupler 30C, the matching circuit 34 does not necessarily include the inductor 60. In the coupler 30C, the matching circuit 34 includes a capacitor 53 as the capacitor 50. The capacitor 53 includes a plurality of capacitor elements 531. The plurality of capacitor elements 531 are arranged circumferentially around the supply line 40, i.e., the central axis of the coupling rod. The plurality of capacitor elements 531 may be arranged at equal intervals. In addition, in the matching circuit 34 of the coupler 30C, each of the plurality of relays 71 is arranged radially outward of a corresponding one of the plurality of capacitor elements 531. That is, the plurality of relays 71 are also arranged circumferentially around the central axis of the coupling rod. In addition, in the coupler 30C, the plurality of relays 71 have the configuration shown in any one of FIGS. 7 to 9. In the matching circuit 34 of the coupler 30C, the plurality of relays 71 are configured to switch between disconnection and connection between each of the plurality of capacitor elements 531 and ground.

[0089] The coupler 30C further includes a printed circuit board 531b. The printed circuit board 531b is disposed within the housing 30h and extends horizontally. The printed circuit board 531b has a substantially circular shape and an opening at its center. The supply line 40 extends through the opening in the printed circuit board 531b. The printed circuit board 531b provides a plurality of capacitor patterns 531e and a ground pattern 531g on its bottom surface. The plurality of capacitor patterns 531e and the ground pattern 531g are formed from a metal such as copper. The plurality of capacitor patterns 531e have a substantially circular shape and are arranged in the circumferential direction around the central axis of the supply line 40, i.e., the coupling rod. The ground pattern 531g extends radially outward from the plurality of capacitor patterns 531e. The ground pattern 531g may have an annular shape. The ground pattern 531g is connected to the bottom of the housing 30h, i.e., to ground, via a plurality of metal supports 53sp.

[0090] In the coupler 30C, the matching circuit 34 further includes a capacitor plate 531p formed from a metal such as copper. The capacitor plate 531p extends below the printed circuit board 531b so as to face the plurality of capacitor patterns 531e. The capacitor plate 531p may have a substantially ring shape. The inner edge of the capacitor plate 531p is connected to the supply line 40.

[0091] Furthermore, in the coupler 30C, the matching circuit 34 includes a plurality of dielectric members 531d. The plurality of dielectric members 531d are formed of, for example, polytetrafluoroethylene. The plurality of dielectric members 531d may have a ring shape. Each of the plurality of dielectric members 531d is sandwiched between a corresponding capacitor pattern among the plurality of capacitor patterns 531e and a capacitor plate 531p. Each of the plurality of capacitor elements 531 described above is composed of one of the plurality of capacitor patterns 531e, a capacitor plate 531p, and a dielectric member among the plurality of dielectric members 531d arranged therebetween.

[0092] The multiple capacitor patterns 531e may have the same area. In this case, the multiple capacitor elements 531 have the same capacitance (electrostatic capacity). Furthermore, the edge of each of the multiple capacitor patterns 531e may be slightly smaller than the size of the multiple dielectric members 531d so that the edge is positioned more inward than the edge of the corresponding one of the multiple dielectric members 531d. This can suppress creeping discharge.

[0093] In the matching circuit 34 of the coupler 30C, each of the multiple relays 71 has a configuration similar to that of the relay 71 described above in the coupler 30A. In the matching circuit 34 of the coupler 30C, a first contact 71t1 of a relay switch 71s of each of the multiple relays 71 is connected to a corresponding one of the multiple capacitor patterns 531e. In addition, a second contact 71t2 of the relay switch 71s of each of the multiple relays 71 is connected to the ground pattern 531g.

[0094] In the coupler 30C, similar to the coupler 30A, the drive circuit 34d is configured to apply a DC voltage signal to the relay coils 71c of each of the plurality of relays 71 to set the state (open or closed) of the relay switch 71s of each of the plurality of relays 71. The control circuit 34c is capable of communicating with the power supply control unit 24c via the communication circuit 34t. The control circuit 34c is notified via the communication circuit 34t of the setting value of the capacitance of the capacitor 53, which is used to reduce the power level of the reflected wave. The control circuit 34c controls the drive circuit 34d to set the state of the relay switch 71s of each of the plurality of relays 71 to the notified setting value.

[0095] A coupler according to yet another exemplary embodiment will be described below with reference to FIGS. 15 and 16. FIG. 15 is a cross-sectional view showing a coupler according to yet another exemplary embodiment. FIG. 16 is a cross-sectional view taken along line XVI-XVI in FIG. 15. FIG. 16 shows a longitudinal cross-sectional structure of a coupler according to yet another exemplary embodiment. A coupler 50D shown in FIGS. 15 and 16 can be used in place of the coupler 30C in the plasma processing apparatus 1C. The coupler 30D will be described below from the perspective of differences from the coupler 30C.

[0096] In the coupler 30D, the supply line 42 is configured as a coaxial line or a coupling rod extending upward from the feed portion 20p. In the coupler 30D, the matching circuit 34 does not need to include the inductor 60. In the coupler 30D, the matching circuit 34 includes a capacitor 54 instead of the capacitor 50. The capacitor 54 includes a plurality of capacitor elements 541. The plurality of capacitor elements 541 are arranged to form one or more columns. In the illustrated example, the plurality of capacitor elements 541 form two columns.

[0097] The matching circuit 34 of the coupler 30D includes a printed circuit board 541b, a capacitor plate 541p, and a plurality of dielectric members 514d. The printed circuit board 541b, the capacitor plate 541p, and the plurality of dielectric members 514d are provided in a housing 30h.

[0098] The printed circuit board 541b is provided inside the housing 30h and extends horizontally. The printed circuit board 541b may have a substantially rectangular shape. The printed circuit board 541b provides a plurality of capacitor patterns 541e and a ground pattern 541g on its bottom surface. The plurality of capacitor patterns 541e and the ground pattern 541g are formed from a metal such as copper. The plurality of capacitor patterns 541e have a substantially circular shape. The plurality of capacitor patterns 541e are arranged to form one or more rows (two rows in the illustrated example) as described above. The ground pattern 541g is connected to the bottom of the housing 30h, i.e., to ground, via a plurality of metal supports 54sp.

[0099] The capacitor plate 541p extends horizontally below the printed circuit board 541b so as to face the plurality of capacitor patterns 541e. The capacitor plate 541p may have a rectangular shape. The capacitor plate 541p constitutes the supply line 31 and, together with the supply line 42, constitutes the supply line 40. The capacitor plate 541p extends in its longitudinal direction from the input portion 30i to the connection portion with the supply line 42.

[0100] Each of the plurality of dielectric members 541d is held between a corresponding capacitor pattern among the plurality of capacitor patterns 541e and a capacitor plate 541p using a screw. The plurality of dielectric members 541d may be formed from polytetrafluoroethylene or the like and may have a ring shape. Each of the plurality of capacitor elements 541 described above is composed of one capacitor pattern among the plurality of capacitor patterns 541e, a capacitor plate 541p, and a dielectric member among the plurality of dielectric members 541d arranged therebetween.

[0101] The multiple capacitor patterns 541e may have the same area. In this case, the multiple capacitor elements 541 have the same capacitance (electrostatic capacity). Furthermore, the edge of each of the multiple capacitor patterns 541e may be slightly smaller than the size of the multiple dielectric members 541d so that the edge is positioned more inward than the edge of the corresponding one of the multiple dielectric members 541d. This can suppress creeping discharge.

[0102] In the matching circuit 34 of the coupler 30D, each of the multiple relays 71 has the same configuration as the relay 71 described above in the coupler 30A. That is, in the coupler 30D, the multiple relays 71 also have the configuration shown in any one of FIGS. 7 to 9 in order to switch between connection and disconnection between each of the multiple capacitor elements 541 and the ground. In the matching circuit 34 of the coupler 30D, a first contact 71t1 of a relay switch 71s of each of the multiple relays 71 is connected to a corresponding capacitor pattern among the multiple capacitor patterns 541e. In addition, a second contact 71t2 of the relay switch 71s of each of the multiple relays 71 is connected to the ground pattern 541g.

[0103] In the coupler 30D, the drive circuit 34d is connected to the relay coils 71c of the multiple relays 71 via a connector 54cn. The drive circuit 34d is configured to apply a DC voltage signal to the relay coils 71c of the multiple relays 71 to set the state (open or closed) of the relay switches 71s of the multiple relays 71. The control circuit 34c is capable of communicating with the power supply control unit 24c via a communication circuit 34t. The power supply control unit 24c notifies the control circuit 34c via the communication circuit 34t of the capacitance setting value of the capacitor 54, which is used to reduce the power level of the reflected wave. The control circuit 34c controls the drive circuit 34d to set the state of the relay switches 71s of the multiple relays 71 to the notified setting value.

[0104] A plasma processing apparatus according to yet another exemplary embodiment will now be described. In the plasma processing apparatus according to this still another exemplary embodiment, the power supply 20p may be located at a radially inner position relative to the position where the load impedance from the power supply 20p is 50Ω. That is, the radial distance from the axis AX to the power supply 20p may be shorter than the above-mentioned r50. In this case, in the variable reactance section of the coupler of the plasma processing apparatus, only the inductor 60 may have a variable reactance. A coupler in which only the inductor 60 has a variable reactance may be, for example, the coupler shown in FIGS. 17 and 18. Note that the other configurations of the plasma processing apparatus in this case are the same as the corresponding configurations of the plasma processing apparatus 1.

[0105] Reference will now be made to Figures 17 and 18. Figure 17 is a cross-sectional view showing a coupler according to yet another exemplary embodiment. Figure 18 is a cross-sectional view taken along line XVIII-XVIII in Figure 17. Figure 18 shows the structure of a longitudinal cross section of a coupler according to yet another exemplary embodiment. Below, a coupler 30E shown in Figures 17 and 18 will be described from the perspective of differences from coupler 30A.

[0106] The coupler 30E includes a transmission line plate 313 made of a metal such as copper. The transmission line plate 313 extends horizontally along its longitudinal direction to connect the input section 30i and the output section 30o to each other. The transmission line plate 313, together with the bottom of the housing 30h, constitutes the feed line 31, which constitutes a microstrip line. The microstrip line has the constant characteristic impedance described above.

[0107] In the coupler 30E, the matching circuit 34 includes an inductor 65 as the inductor 60. The inductor 65 includes an inductor pattern 65p. The inductor pattern 65p is formed on the back surface of a printed circuit board 65b. The printed circuit board 65b extends horizontally above the transmission line plate 313. One end of the inductor pattern 65p may be disposed at the center of the inductor pattern 65p or the center of the printed circuit board 65b. One end of the inductor pattern 65p is connected to a connection point 30s of the transmission line plate 313 via a metal support 30sp (connection member). The other end of the inductor pattern 65p is connected to a ground pattern 65g formed on the back surface of the printed circuit board 65b. The ground pattern 65g is connected to the bottom of the housing 30h via a plurality of metal supports 65sp.

[0108] In the coupler 30E, the matching circuit 34 further includes a plurality of relays 71. The plurality of relays 71 are provided on a printed circuit board 65b. Each of the plurality of relays 71 in the coupler 30E has a configuration similar to that of the relay 71 in the coupler 30A described above. That is, the plurality of relays 71 in the coupler 30E also have the configuration shown in any one of FIGS. 7 to 9 in order to switch between connection and disconnection between each of a plurality of inductor elements 651 (described below) and the ground.

[0109] The first contact 71t1 of each of the plurality of relays 71 is connected to a different position on the inductor pattern 65p between one end and the other end of the inductor pattern 65p. The second contact 71t2 of each of the plurality of relays 71 is connected to the ground pattern 65g. The plurality of relays 71 divide the plurality of inductor patterns 65p into a plurality of inductor elements 651. The plurality of inductor elements 651 are a plurality of reactance elements. In the illustrated example, the plurality of relays 71 includes four relays RL1 to RL4. In this example, the inductor pattern 65p is divided into five inductor elements 651a to 651e between one end and the other end of the inductor pattern 65p.

[0110] In the matching circuit 34 of the coupler 30E, the driver circuit 34d is connected to the relay coils 71c of the multiple relays 71 via the connector 65cn. The driver circuit 34d is configured to apply a DC voltage signal to the relay coils 71c of the multiple relays 71 to set the state (open or closed) of the relay switches 71s of the multiple relays 71. The control circuit 34c can communicate with the power supply controller 24c via the communication circuit 34t. The control circuit 34c receives notification from the power supply controller 24c via the communication circuit 34t of the inductance setting value of the inductor 65 for reducing the power level of the reflected wave. The control circuit 34c controls the driver circuit 34d to set the state of the relay switches 71s of the multiple relays 71 to the notified setting value. In the coupler 30E, the inductance of the inductor 65 can be adjusted by setting the state of the relay switches 71s of the multiple relays 71.

[0111] FIG. 19 is a table illustrating the relationship between the state (open or closed) of the relay switch of each of multiple relays in a coupler according to yet another exemplary embodiment and the inductance. The table in FIG. 19 illustrates the relationship between the state of the relay switch 71s of each of relays RL1-RL4 and the inductance of the inductor 65. The inductance L of the inductor 65 is L0 when the relay switch 71s of each of relays RL1-RL4 is in the open state. When the relay switch 71s of each of relays RL1-RL4 is in the closed state, the inductance of the inductor 65 is provided. As a result, as shown in the table in FIG. 19, by adjusting the state of the relay switch 71s of each of relays RL1-RL4, the inductance of the inductor 65 can be changed in 16 steps by the same inductance change amount.

[0112] A configuration for detecting a fault in a plurality of relays that can be employed in a coupler according to various exemplary embodiments will now be described with reference to Figure 20. Figure 20 is a diagram illustrating an example of a configuration for detecting a fault in a plurality of relays that can be employed in a coupler according to various exemplary embodiments.

[0113] As shown in FIG. 20 , in various exemplary embodiments, the variable reactance unit 36 ​​includes a plurality of reactance elements 361. The plurality of reactance elements 361 are the above-described plurality of capacitor elements and / or a plurality of inductor elements. The fault detection configuration shown in FIG. 20 is applied to a plurality of relays 71 for switching between disconnection and connection between the plurality of reactance elements 361 and ground. Note that in the example of FIG. 20 , a plurality of capacitor elements 501 are shown as the plurality of reactance elements 361. In another embodiment, the fault detection configuration for a plurality of relays 71 may be similarly applied to a plurality of inductor elements.

[0114] 20, one end of each of the plurality of reactance elements 361 (e.g., the plurality of capacitor elements 501) is connected to the connection point 30s. The other end of each of the plurality of reactance elements 361 is connected to a first contact 71t1 of a relay switch 71s of a corresponding one of the plurality of relays 71. A second contact 71t2 of the relay switch 71s of each of the plurality of relays 71 is connected to ground.

[0115] As shown in Fig. 20, the matching circuit 34 includes a drive circuit 34d and a control circuit 34c. The drive circuit 34d shown in Fig. 20 has a configuration similar to that shown in Fig. 8, but may also have other configurations shown in Figs. 7 and 9.

[0116] 20 is configured to set the state (open state or closed state) of the relay switch 71s of each of the multiple relays 71 under the control of the control circuit 34c. The drive circuit 34d may include multiple drive circuits 71d that individually control the state of the relay switch 71s of each of the multiple relays 71. The multiple drive circuits 71d may be provided as elements of each of the multiple relays 71. Each of the multiple drive circuits 71d is configured to generate a DC voltage signal for closing the relay switch 71s of a corresponding relay among the multiple relays 71.

[0117] 20, the relay coils 71c of the plurality of relays 71 may be floating from the ground with respect to high frequencies. In this case, each of the plurality of drive circuits 71d is connected to the transformer 71. T1 , a pulse generator 71p, and a DC voltage generating circuit 71g. T1 The primary coil of the transistor 71 Tr The pulse generator 71p generates a high frequency pulse to drive the transistor 71 Tr A high frequency pulse is supplied to the control terminal of the transistor 71. The frequency of the high frequency pulse is, for example, 160 kHz. Tr When a high frequency pulse is applied to the transformer 71 T1 A pulse current is generated in the secondary coil.

[0118] The DC voltage generating circuit 71g includes a corresponding relay coil 71c and a transformer 71 T1 The DC voltage generating circuit 71g is connected between the capacitor 71 and the secondary coil. Cw , first diode 71 D1 , and the second diode 71 D2 One end of the secondary coil is connected to a second diode 71 D2 The second diode 71 is connected to one end of the corresponding relay coil 71c via the D2 The anode of the second diode 71 is connected to one end of the secondary coil. D2 The cathode of the relay coil 71c is connected to one end of the corresponding relay coil 71c.

[0119] Capacitor 71 Cw and the first diode 71 D1 The corresponding relay coil 71c and transformer 71 T1 The first diode 71 is connected in parallel between the first diode 71 and the secondary coil of the D1 The cathode of the second diode 71 is connected to one end of the corresponding relay coil 71c. D2 The cathode of the first diode 71 is connected to the cathode of the first diode 71. D1 The anode of each relay coil 71c is connected to the other end of the corresponding relay coil 71c and the other end of the secondary coil.

[0120] The pulse current generated in the secondary coil is passed through the second diode 71 D2 via capacitor 71 Cw When the high frequency pulse is in the OFF state, a return current generated by the inductance component of the relay coil 71c flows through the first diode 71. D1 This causes the current to flow through capacitor 71 Cw A DC voltage is generated at the relay coil 71c, and a DC voltage signal is applied to the relay coil 71c, causing the relay switch 71s to be set to a closed state.

[0121] As shown in FIG. 20, the matching circuit 34 includes a common resistor 34 Ru (shunt resistor) and multiple resistors 34Rd Includes common resistor 34 Ru One end of each of the resistors 34 is connected to a DC power supply that outputs a voltage Vdd. Rd are the first contacts 71t1 of the plurality of relays 71 and the common resistor 34 Ru The other end of the common resistor 34 is connected to the other end of the common resistor 34. Ru The other end of the common resistor 34 is connected to an A / D conversion terminal of the control circuit 34c via an amplifier Au. Ru Between the other end of the amplifier Au and the electrical path and the ground, a capacitor 34 for bypassing high frequency current is provided. Cf is connected.

[0122] Common resistor 34 Ru A voltage Vu shown in the following equation (F3) is generated across both ends of the Vu=(Ru / (Ru+Rd / N))×Vdd…(F3) where Ru is the common resistor 34 Ru Rd is the resistance of multiple resistors 34 Rd are the resistance values ​​of each of the relays 71, and N is the number of relays 71 that are in the closed state.

[0123] As shown in equation (F3), the voltage Vu increases as the number of relays 71 in the closed state increases. The voltage Vu is input to the A / D conversion terminal of the control circuit 34c via the amplifier Au. The control circuit 34c generates a digital value by A / D conversion of the voltage input to the A / D conversion terminal. The control circuit 34c pre-stores ideal values ​​for the digital value corresponding to the number of relays 71 in the closed state. The control circuit 34c detects a failure of one of the multiple relays 71 by comparing the digital value obtained by A / D conversion of the voltage input to the A / D conversion terminal with an ideal value corresponding to the number of relays 71 in the closed state at that time. For example, the control circuit 34c detects a failure in one of the multiple relays 71 when the difference between the digital value obtained by A / D conversion and the ideal value corresponding to the number of relays 71 in the closed state at that time is greater than a threshold value. In this way, the control circuit 34c can function as a detector configured to detect a failure of the multiple relays 71.

[0124] The matching circuit 34 also includes a common resistor 34 Rs The common resistor 34 may further include a shunt resistor. Rs One end of the resistor 34 is connected to a DC power supply that outputs a voltage Vdd. Rs The other end of the transformer 71 T1 The common resistor 34 is connected to one end of the primary coil of the Rs The other end of the resistor 34 is connected to another A / D conversion terminal of the control circuit 34c via an amplifier As. Rs Outputs voltage Vdd to common resistor 34 Rs The voltage Vs across the transformer 71 T1 This value varies depending on the number of failed drive circuits 71d on the primary side of the control circuit 34c. Therefore, by comparing the digital value obtained by A / D conversion of the voltage input to another A / D conversion terminal of the control circuit 34c with a pre-stored value, it is possible to detect a failure in any of the drive circuits 71d.

[0125] Although various exemplary embodiments have been described above, the present invention is not limited to the above-described exemplary embodiments, and various additions, omissions, substitutions, and modifications may be made. Furthermore, elements in different embodiments may be combined to form other embodiments.

[0126] Various exemplary embodiments included in the present disclosure are now described in [E1] to [E20] below.

[0127] [E1] a plurality of reactance elements connected to a supply line for high frequency power for plasma generation; a plurality of relays each including a relay switch and a relay coil, each having a first contact connected to a corresponding one of the plurality of reactance elements and a second contact connected to ground; Equipped with Each of the plurality of relays at least one diode connected in parallel with the relay coil and configured to rectify high frequency current flowing through a parasitic capacitance between the relay coil and the corresponding reactance element; at least one capacitor connected in parallel with the relay coil, the at least one capacitor configured to generate a DC voltage applied to the relay coil in response to a current generated by rectifying the high frequency current by the at least one diode; and Including, matching circuit.

[0128] [E2] the relay switch has a characteristic of transitioning from a closed state to an open state when a DC voltage applied to the relay coil drops to a voltage level equal to or lower than a threshold voltage level; the at least one capacitor has a capacitance set so that the DC voltage generated by the at least one capacitor has a voltage level higher than the threshold voltage level. The matching circuit described in E1.

[0129] [E3] The matching circuit of any one of E1 to E2, wherein each of the plurality of relays includes a driver circuit configured to apply a DC voltage signal to the relay coil when the relay switch is set to a closed state.

[0130] [E4] The matching circuit of E3, wherein each of the plurality of relays further includes a choke coil connected between the drive circuit and the relay coil.

[0131] [E5] In each of the plurality of relays, the relay coil is provided so as to float from ground with respect to high frequencies, The drive circuit a transformer having a primary coil and a secondary coil; a pulse generator connected to the primary coil and configured to supply high frequency pulses to the primary coil; a DC voltage generating circuit including the at least one diode and the at least one capacitor, connected between the secondary coil and the relay coil, and configured to generate the DC voltage signal; Including, Matching circuit as described in E3.

[0132] [E6] the at least one diode includes a first diode having a cathode connected to one end of the relay coil and another end connected to the other end of the relay coil; the DC voltage generating circuit further includes a second diode having a cathode connected to the one end of the relay coil and the cathode of the first diode, and an anode connected to one end of the secondary coil. The matching circuit described in E5.

[0133] [E7] The at least one capacitor a first capacitor having one end connected to one end of the relay coil; a second capacitor having one end connected to the other end of the first capacitor and one end of the secondary coil, and the other end connected to the other end of the relay coil; Including, The at least one diode a first diode having an anode connected to the other end of the relay coil and the other end of the second capacitor, and a cathode connected to the other end of the secondary coil; a second diode having an anode connected to the cathode of the first diode and the other end of the secondary coil, and a cathode connected to the one end of the relay coil and the one end of the first capacitor; Including, The matching circuit described in E5.

[0134] [E8] The matching circuit according to any one of E1 to E7, wherein the supply line is configured as a transmission line that is a distributed constant line having a constant impedance.

[0135] [E9] The matching circuit according to E8, wherein the feed line is a microstrip line.

[0136] [E10] a common resistor connected to a DC power supply; a plurality of resistors, each connected between the common resistor and the first contact of the relay switch of a corresponding one of the plurality of relays; a detector configured to detect a fault in the plurality of relays based on a voltage across the common resistor; The matching circuit according to any one of E1 to E9, further comprising:

[0137] [E11] The matching circuit according to any one of E1 to E10, wherein the plurality of reactance elements are a plurality of capacitor elements.

[0138] [E12] a capacitor plate connected to the supply line; a printed circuit board having a plurality of capacitor patterns and on which the plurality of relays are mounted; a plurality of dielectric members each disposed between a corresponding one of the plurality of capacitor patterns and the capacitor plate; Further provided with each of the plurality of capacitor elements is composed of the capacitor plate, a corresponding capacitor pattern among the plurality of capacitor patterns, and a dielectric member among the plurality of dielectric members that is arranged between the capacitor plate and the corresponding capacitor pattern; The matching circuit described in E11.

[0139] [E13] The matching circuit according to E12, wherein the plurality of capacitor elements have the same capacitance.

[0140] [E14] The plurality of capacitor elements Each of the first electrodes has a different area; a second electrode common to the plurality of capacitor elements, the second electrode being arranged to face the first electrodes of the plurality of capacitor elements with a dielectric member interposed therebetween; Including, The capacitance of each of the plurality of capacitor elements is C m =0.5×C m-1 Fulfilling where C m is the capacitance of the m-th capacitor element among the first to M-th capacitor elements, which are the plurality of capacitor elements, The matching circuit described in E11.

[0141] [E15] The matching circuit according to any one of E1 to E10, wherein the plurality of reactance elements are a plurality of inductor elements.

[0142] [E16] Further comprising a conductor pattern, a relay switch of each of the plurality of relays is connected in parallel between the conductor pattern and ground so as to divide the conductor pattern into the plurality of inductor elements; Matching circuit described in E15.

[0143] [E17] The matching circuit according to any one of E1 to E10, wherein the plurality of reactance elements includes a plurality of capacitor elements and a plurality of inductor elements.

[0144] [E18] a chamber; a high frequency power supply capable of changing the frequency of the output high frequency power; an introduction section disposed to introduce electromagnetic waves into a plasma generation region within the chamber; a resonator having a feeding portion which is an inlet of an electromagnetic wave, the inlet portion including a waveguide for propagating the electromagnetic wave; a coupling section including an input section for the high frequency power and the matching circuit according to any one of E11 to E14, the coupling section being connected between the high frequency power source and the resonator; Equipped with The resonator comprises: an inner periphery extending around a central axis of the chamber and the resonator; a periphery extending about the central axis; the waveguide having a layer structure in which layers are alternately folded between the inner peripheral portion and the outer peripheral portion; an upper portion located in the uppermost layer of the layer structure and having an upper end at the outer periphery; a lower portion located in the lowest layer of the layer structure and including a lower end connected to the introduction portion; Including, the power supply unit is disposed inside and at the upper end of the upper end, and is provided at a position outside a radial position where impedance on the load side from the power supply unit is 50Ω. Plasma processing equipment.

[0145] [E19] a chamber; a high frequency power supply capable of changing the frequency of the output high frequency power; an introduction section disposed to introduce electromagnetic waves into a plasma generation region within the chamber; a resonator having a feeding portion which is an inlet of an electromagnetic wave, the inlet portion including a waveguide for propagating the electromagnetic wave; a coupling section connected between the high frequency power source and the resonator, the coupling section including an input section for the high frequency power and a matching circuit according to E15 or E16; Equipped with The resonator comprises: an inner periphery extending around a central axis of the chamber and the resonator; a periphery extending about the central axis; the waveguide having a layer structure in which layers are alternately folded between the inner peripheral portion and the outer peripheral portion; an upper portion located in the uppermost layer of the layer structure and having an upper end at the outer periphery; a lower portion located in the lowest layer of the layer structure and including a lower end connected to the introduction portion; Including, the power supply unit is disposed inside the upper end and at the upper portion, and is provided at a position inside a radial position where impedance from the power supply unit on the load side is 50Ω. Plasma processing equipment.

[0146] [E20] a chamber; a high frequency power supply capable of changing the frequency of the output high frequency power; an introduction section disposed to introduce electromagnetic waves into a plasma generation region within the chamber; a resonator having a feeding portion which is an inlet of an electromagnetic wave, the inlet portion including a waveguide for propagating the electromagnetic wave; a coupling section connected between the high frequency power source and the resonator, the coupling section including an input section for the high frequency power and a matching circuit according to E17; Equipped with The resonator comprises: an inner periphery extending around a central axis of the chamber and the resonator; a periphery extending about the central axis; the waveguide having a layer structure in which layers are alternately folded between the inner peripheral portion and the outer peripheral portion; an upper portion located in the uppermost layer of the layer structure and having an upper end at the outer periphery; a lower portion located in the lowest layer of the layer structure and including a lower end connected to the introduction portion; Including, the power supply unit is disposed inside and above the upper end, and is provided at a radial position where impedance on the load side from the power supply unit is 50Ω. Plasma processing equipment.

[0147] From the foregoing, it will be understood that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the appended claims. [Explanation of symbols]

[0148] 1...plasma processing apparatus, 10...chamber, 12...substrate support portion, 16...introduction portion, 20...resonator, 20w...waveguide, 20p...power supply portion, 24...high frequency power supply, 30...coupler, 30i...input portion, 31...supply line, 34...matching circuit, 36...variable reactance portion, 40...supply line, 50...capacitor, 60...inductor, 71...relay, 71s...relay switch, 71t1...first contact, 71t2...second contact, 71c...relay coil, 71 Cw … Capacitor, 71 D ... diode, 71d... drive circuit.

Claims

1. a plurality of reactance elements connected to a supply line for high frequency power for plasma generation; a plurality of relays each including a relay switch and a relay coil, each having a first contact connected to a corresponding one of the plurality of reactance elements and a second contact connected to ground; Equipped with Each of the plurality of relays at least one diode connected in parallel with the relay coil and configured to rectify high frequency current flowing through a parasitic capacitance between the relay coil and the corresponding reactance element; at least one capacitor connected in parallel with the relay coil, the at least one capacitor configured to generate a DC voltage applied to the relay coil in response to a current generated by rectifying the high frequency current by the at least one diode; and Including, matching circuit.

2. the relay switch has a characteristic of transitioning from a closed state to an open state when a DC voltage applied to the relay coil drops to a voltage level equal to or lower than a threshold voltage level; the at least one capacitor has a capacitance set so that the DC voltage generated by the at least one capacitor has a voltage level higher than the threshold voltage level. The matching circuit according to claim 1 .

3. The matching circuit of claim 1 , wherein each of the plurality of relays includes a driver circuit configured to apply a DC voltage signal to the relay coil when the relay switch is set to a closed state.

4. The matching circuit according to claim 3 , wherein each of the plurality of relays further includes a choke coil connected between the drive circuit and the relay coil.

5. In each of the plurality of relays, the relay coil is provided so as to float from ground with respect to high frequencies, The drive circuit a transformer having a primary coil and a secondary coil; a pulse generator connected to the primary coil and configured to supply high frequency pulses to the primary coil; a DC voltage generating circuit including the at least one diode and the at least one capacitor, connected between the secondary coil and the relay coil, and configured to generate the DC voltage signal; Including, The matching circuit according to claim 3 .

6. the at least one diode includes a first diode having a cathode connected to one end of the relay coil and another end connected to the other end of the relay coil; the DC voltage generating circuit further includes a second diode having a cathode connected to the one end of the relay coil and the cathode of the first diode, and an anode connected to one end of the secondary coil. The matching circuit according to claim 5 .

7. The at least one capacitor a first capacitor having one end connected to one end of the relay coil; a second capacitor having one end connected to the other end of the first capacitor and one end of the secondary coil, and the other end connected to the other end of the relay coil; Including, The at least one diode a first diode having an anode connected to the other end of the relay coil and the other end of the second capacitor, and a cathode connected to the other end of the secondary coil; a second diode having an anode connected to the cathode of the first diode and the other end of the secondary coil, and a cathode connected to the one end of the relay coil and the one end of the first capacitor; Including, The matching circuit according to claim 5 .

8. 8. The matching circuit according to claim 1, wherein the supply line is configured as a transmission line that is a distributed constant line having a constant impedance.

9. The matching circuit according to claim 8 , wherein the feed line is a microstrip line.

10. a common resistor connected to a DC power supply; a plurality of resistors, each connected between the common resistor and the first contact of the relay switch of a corresponding one of the plurality of relays; a detector configured to detect a fault in the plurality of relays based on a voltage across the common resistor; The matching circuit according to any one of claims 1 to 7, further comprising:

11. 8. The matching circuit according to claim 1, wherein the plurality of reactance elements are a plurality of capacitor elements.

12. a capacitor plate connected to the supply line; a printed circuit board having a plurality of capacitor patterns and on which the plurality of relays are mounted; a plurality of dielectric members each disposed between a corresponding one of the plurality of capacitor patterns and the capacitor plate; Further provided with each of the plurality of capacitor elements is composed of the capacitor plate, a corresponding capacitor pattern among the plurality of capacitor patterns, and a dielectric member among the plurality of dielectric members that is arranged between the capacitor plate and the corresponding capacitor pattern; The matching circuit according to claim 11.

13. The matching circuit according to claim 12 , wherein the plurality of capacitor elements have the same capacitance.

14. The plurality of capacitor elements Each of the first electrodes has a different area; a second electrode common to the plurality of capacitor elements, the second electrode being arranged to face the first electrodes of the plurality of capacitor elements with a dielectric member interposed therebetween; Including, The capacitance of each of the plurality of capacitor elements is C ｍ = 0.5 × C ｍ－１ Fulfilling Here, C ｍ is the capacitance of the m-th capacitor element among the first to M-th capacitor elements, which are the plurality of capacitor elements, The matching circuit according to claim 11.

15. 8. The matching circuit according to claim 1, wherein the plurality of reactance elements are a plurality of inductor elements.

16. Further comprising a conductor pattern, a relay switch of each of the plurality of relays is connected in parallel between the conductor pattern and ground so as to divide the conductor pattern into the plurality of inductor elements; 16. The matching circuit of claim 15.

17. 8. The matching circuit according to claim 1, wherein the plurality of reactance elements include a plurality of capacitor elements and a plurality of inductor elements.

18. a chamber; a high frequency power supply capable of changing the frequency of the output high frequency power; an introduction section disposed to introduce electromagnetic waves into a plasma generation region within the chamber; a resonator having a feeding portion which is an inlet of an electromagnetic wave, the inlet portion including a waveguide for propagating the electromagnetic wave; a coupling section connected between the high frequency power source and the resonator, the coupling section including an input section for the high frequency power and the matching circuit according to claim 11; Equipped with The resonator comprises: an inner periphery extending around a central axis of the chamber and the resonator; a periphery extending about the central axis; the waveguide having a layer structure in which layers are alternately folded between the inner peripheral portion and the outer peripheral portion; an upper portion located in the uppermost layer of the layer structure and having an upper end at the outer periphery; a lower portion located in the lowest layer of the layer structure and including a lower end connected to the introduction portion; Including, the power supply unit is disposed inside and at the upper end of the upper end, and is provided at a position outside a radial position where impedance from the power supply unit on the load side is 50Ω. Plasma processing equipment.

19. a chamber; a high frequency power supply capable of changing the frequency of the output high frequency power; an introduction section disposed to introduce electromagnetic waves into a plasma generation region within the chamber; a resonator having a feeding portion which is an inlet of an electromagnetic wave, the inlet portion including a waveguide for propagating the electromagnetic wave; a coupling section connected between the high frequency power source and the resonator, the coupling section including an input section for the high frequency power and the matching circuit according to claim 15; Equipped with The resonator comprises: an inner periphery extending around a central axis of the chamber and the resonator; a periphery extending about the central axis; the waveguide having a layer structure in which layers are alternately folded between the inner peripheral portion and the outer peripheral portion; an upper portion located in the uppermost layer of the layer structure and having an upper end at the outer periphery; a lower portion located in the lowest layer of the layer structure and including a lower end connected to the introduction portion; Including, the power supply unit is disposed inside the upper end and at the upper portion, and is provided at a position inside a radial position where an impedance on a load side from the power supply unit is 50 Ω. Plasma processing equipment.

20. a chamber; a high frequency power supply capable of changing the frequency of the output high frequency power; an introduction section disposed to introduce electromagnetic waves into a plasma generation region within the chamber; a resonator having a feeding portion which is an inlet of an electromagnetic wave, the inlet portion including a waveguide for propagating the electromagnetic wave; a coupling section connected between the high frequency power source and the resonator, the coupling section including an input section for the high frequency power and the matching circuit according to claim 17; Equipped with The resonator comprises: an inner periphery extending around a central axis of the chamber and the resonator; a periphery extending about the central axis; the waveguide having a layer structure in which layers are alternately folded between the inner peripheral portion and the outer peripheral portion; an upper portion located in the uppermost layer of the layer structure and having an upper end at the outer periphery; a lower portion located in the lowest layer of the layer structure and including a lower end connected to the introduction portion; Including, the power supply unit is disposed inside and above the upper end, and is provided at a radial position where impedance on the load side from the power supply unit is 50Ω. Plasma processing equipment.

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