Plasma processing apparatus

Abstract

To provide a technique for suppressing a maximum voltage in a coupler due to a high frequency power transmitted in the coupler having a variable impedance and connected between the high frequency power supply and a resonator.SOLUTION: A plasma processing apparatus to be disclosed includes: a chamber; a high frequency power supply; an introduction part; a resonator; a coupler; and a transmission line. The high frequency power supply is configured to be capable of changing a frequency of the high frequency power to be output. The introduction part is arranged to introduce an electromagnetic wave into a plasma generation region in a chamber. The resonator has a feeding part that is an inlet of the electromagnetic wave, and includes a waveguide for propagating the electromagnetic wave to the introduction part. The coupler includes an input part for the high frequency power, has a variable impedance, and is connected between the high frequency power supply and the resonator. The transmission line is a distributed constant line extending from the input part to the feeding part through the coupler, and has a constant characteristic impedance.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Plasma processing apparatuses are used in plasma processing of substrates. One type of plasma processing apparatus includes a chamber, a high-frequency power supply, a resonator, an introduction section, and a matching box. The high-frequency power supply is coupled to the resonator. Electromagnetic waves from the resonator are supplied into the chamber from the introduction section. The matching box is connected between the high-frequency power supply and the resonator. Such a plasma processing apparatus is described in Patent Document 1 listed below. There is a matcher. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-92031 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique for suppressing the maximum voltage in a coupler that has a variable impedance and is connected between a high frequency power source and a resonator and that is caused by high frequency power transmitted through the coupler. [Means for solving the problem]

[0005] In one exemplary embodiment, a plasma processing apparatus is disclosed. The plasma processing apparatus includes a chamber, a radio frequency power supply, an introduction section, a resonator, a coupler, and a transmission line. The radio frequency power supply is configured to be able to change the frequency of the radio frequency power it outputs. The introduction section is positioned to introduce electromagnetic waves into a plasma generation region in the chamber. The resonator has a power supply section that is an entrance for the electromagnetic waves, and the introduction section includes a waveguide for propagating the electromagnetic waves. The coupler includes an input section for the radio frequency power, has variable impedance, and is connected between the radio frequency power supply and the resonator. The transmission line is a distributed constant line that extends from the input section through the coupler to the power supply section, and has a constant characteristic impedance. [Effects of the Invention]

[0006] According to one exemplary embodiment, it is possible to suppress the maximum voltage in a coupler that has a variable impedance and is connected between a high-frequency power source and a resonator, resulting from the high-frequency power transmitted in the coupler. [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] 1 is an admittance chart associated with a coupler according to one exemplary embodiment. [Figure 6] FIG. 10 is a cross-sectional view illustrating a coupler according to another exemplary embodiment. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6. [Figure 8] FIG. 10 is a cross-sectional view illustrating a coupler according to yet another exemplary embodiment. [Figure 9]FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 8. [Figure 10] FIG. 9 is a cross-sectional view taken along line XX in FIG. 8. [Figure 11] FIG. 1 illustrates an embodiment of an inductor that may be employed in a coupler according to various exemplary embodiments. [Figure 12] FIG. 10 is a cross-sectional view illustrating a coupler according to yet another exemplary embodiment. [Figure 13] FIG. 13 is a cross-sectional view taken along line XIII-XIII in FIG. 12. [Figure 14] 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 15] 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 m0 This 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 and 4 will be referred to below in addition to FIG. 1. FIG. 3 is a cross-sectional view showing a coupler according to an exemplary embodiment. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. FIG. 4 shows the structure of a coupler in a longitudinal cross section according to an exemplary embodiment. The coupler 30A shown in FIGS. 3 and 4 can be used as the coupler 30 of the plasma processing apparatus 1.

[0035] The coupler 30A includes a printed circuit board 311 and a dielectric member 312. The printed circuit board 311 is provided within a housing 30h. The printed circuit board 311 has a transmission line pattern 311t. The transmission line pattern 311t extends along its longitudinal direction from the input section 30i to a connection point with the supply line 42. The transmission line pattern 311t may be formed on both sides of the printed circuit board 311. The transmission line patterns 311t on both sides of the printed circuit board 311 have the same shape and are connected by a plurality of via conductors arranged along the edges of the transmission line pattern 311t. The dielectric member 312 is provided between the transmission line pattern 311t and the bottom of the housing 30h. The dielectric member 312 is made of a material such as polytetrafluoroethylene.

[0036] The transmission line pattern 311t forms a microstrip line between the transmission line pattern 311t and the bottom of the housing 30h. This microstrip line has the above-mentioned constant characteristic impedance. Note that the dielectric member 312 does not have to be disposed in the region between the transmission line pattern 311t and the bottom of the housing 30h. The region between the transmission line pattern 311t and the bottom of the housing 30h may be filled with, for example, air.

[0037] 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.

[0038] The transmission line pattern 311t, i.e., the transmission line, includes a connection point 30s. The connection point 30s is located between the input portion 30i and the output portion 30o. A capacitor 51 is connected to the connection point 30s via a metal connection plate 51p. The capacitor 51 is a variable capacitor. The capacitor 51 includes a fixed electrode 51s, a rotating electrode 51r, and a rotating shaft 51a. The rotating shaft 51a extends in the horizontal direction and is supported to be rotatable around its central axis. Note that the rotating shaft 51a may extend in a direction other than the horizontal direction, for example, vertically.

[0039] The fixed electrode 51s is fixed so as not to move and is disposed substantially parallel to the rotating electrode 51r. The rotating electrode 51r has a fan-like or semicircular shape and is connected to the rotating shaft 51a so as to be rotatable together with the rotating shaft 51a. The capacitor 51 may include a plurality of fixed electrodes 51s and a plurality of rotating electrodes 51r arranged alternately.

[0040] In this embodiment, the coupler 30A further includes a driving source 51m, such as a motor, and a communication circuit 34t. The driving source 51m is coupled to the rotating shaft 51a to rotate the rotating shaft 51a and the rotating electrode 51r. The driving source 51m rotates the rotating shaft 51a and the rotating electrode 51r in response to an electrical signal from the driving circuit 34d. The driving circuit 34d is controlled by the control circuit 34c. The power supply control unit 24c notifies the control circuit 34c via the communication circuit 34t of the rotation angle position of the rotating electrode 51r for reducing the power level of the reflected wave. The control circuit 34c controls the driving source 51m via the driving circuit 34d to adjust the rotation angle position of the rotating electrode 51r to the notified rotation angle position. This allows the capacitor 51 to change its capacitance (electrostatic capacitance).

[0041] Furthermore, one end of an inductor pattern 311i, which is a conductor pattern, is connected to the connection point 30s. The inductor pattern 311i extends from one end to the other. The inductor pattern 311i may be provided on both sides of the printed circuit board 311. The inductor patterns 311i on both sides of the printed circuit board 311 have the same shape and are connected by multiple via conductors arranged along the edges of the inductor pattern 311i. By providing the inductor patterns 311i on both sides of the printed circuit board 311, high-frequency power loss in the inductor 61 is suppressed.

[0042] The inductor pattern 311i is configured to be able to change the length (electrical length) from one end to the portion shorted to ground. In the embodiment of FIG. 3, 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 hole of the plurality of holes 311h into a screw hole of a short-circuiting member 61sp (e.g., a metal support) sandwiched between the inductor pattern 311i and the bottom of the housing 30h. The length of the inductor 61 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 61 to be changed.

[0043] 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.

[0044] Further reference is now made to FIG. 5 , which is an admittance chart associated with a coupler according to one exemplary embodiment. In FIG. 5 , “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. 5 , “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.

[0045] 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. 5 ) 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. 5 ) satisfy the orthogonal condition in a coordinate system having real and imaginary axes that are orthogonal to each other, as shown in FIG. 5 .

[0046] 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.

[0047] Specific conditions for satisfying the orthogonal condition will be described below with further reference to Fig. 5. When the orthogonal condition is satisfied, the impedance on the load side of connection point 30s changes along the thick solid line in Fig. 5 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. 5. In Fig. 5, 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. 5 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:

[0048] Here, the angle θ r is 4π×L r / λgr and 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 angles 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

[0049] Hereinafter, a coupler according to another exemplary embodiment will be described with reference to FIGS. 6 and 7. FIG. 6 is a cross-sectional view showing a coupler according to another exemplary embodiment. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6. FIG. 7 shows the structure of a coupler according to an exemplary embodiment in a longitudinal cross section. A coupler 30B shown in FIGS. 6 and 7 can be used as the coupler 30 of the plasma processing apparatus 1. Hereinafter, the coupler 30B will be described from the viewpoint of differences from the coupler 30A.

[0050] In coupler 30B, printed circuit board 311 may be made of a material having a small dielectric loss tangent, for example, a glass epoxy material having inorganic material dispersed therein.

[0051] In the coupler 30B, the transmission line pattern 311t and the inductor pattern 311i are formed on the back surface of the printed circuit board 311. 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. In the coupler 30B, the inductor pattern 311i forms the inductor 62 of the variable reactance unit 36. Other configurations of the inductor 62 are similar to those of the inductor 61.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] In the coupler 30B, the matching circuit 34 further includes a plurality of relays 71. 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 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 of the plurality of relays 71 is connected to a ground pattern 311g provided on the back surface of the printed circuit board 311. The ground pattern 311g is connected to the bottom of the housing 30h, i.e., to ground, via a plurality of short-circuit members 52sp (e.g., metal posts).

[0058] 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.

[0059] 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.

[0060] A coupler according to yet another exemplary embodiment will be described below with reference to FIGS. 8 to 10. FIG. 8 is a cross-sectional view showing a coupler according to yet another exemplary embodiment. FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 8. FIG. 10 is a cross-sectional view taken along line XX in FIG. 8. Note that FIG. 8 shows the structure of a coupler according to yet another exemplary embodiment in a longitudinal cross section taken along line VIII-VIII in FIG. 9. A coupler 30C shown in FIGS. 8 to 10 can be used as the coupler 30 of the plasma processing apparatus 1. The coupler 30C will be described below from the perspective of differences from the coupler 30A.

[0061] The coupler 30C 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. A 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.

[0062] The coupler 30C includes a capacitor 53 as the capacitor 50. The capacitor 53 has a plurality of capacitor elements 531. To provide the plurality of capacitor elements 531, the capacitor 53 includes a capacitor plate 531p, a plurality of dielectric members 531d, and a plurality of capacitor patterns 531e on a printed circuit board 531b.

[0063] The capacitor plate 531p is made of a metal such as copper and extends horizontally above the transmission line plate 313. The transmission line plate 313 has a connection point 30s. The capacitor plate 531p 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.

[0064] The printed circuit board 531b extends horizontally above the capacitor plate 531p. The plurality of capacitor patterns 531e are formed on the rear surface (lower surface) of the printed circuit board 531b so as to face the capacitor plate 531p. Each of the plurality of capacitor patterns 531e may have a substantially circular shape. The plurality of capacitor patterns 531e may be arranged along the longitudinal direction of the capacitor plate 531p. In the illustrated example, the plurality of capacitor patterns 531e are arranged to form two rows extending in a direction parallel to the longitudinal direction of the capacitor plate 531p. The printed circuit board 531b may have a slit 531bh penetrating the printed circuit board 531b in its thickness direction. The slit 531bh may be formed between the two rows of the plurality of capacitor patterns 531e. The slit 531bh can reduce the parasitic capacitance of the printed circuit board 531b.

[0065] Each of the plurality of dielectric members 531d is clamped between a corresponding one of the plurality of capacitor patterns 531e and a capacitor plate 531p using a screw. The plurality of dielectric members 531d may be formed from polytetrafluoroethylene or the like and may have a ring shape. The edge of each of the plurality of capacitor patterns 531e may be slightly smaller than the size of the plurality of dielectric members 531d so that the edge is positioned more inward than the edge of the corresponding one of the plurality of dielectric members 531d. This can suppress creeping discharge.

[0066] In the capacitor 53, each of the plurality of capacitor elements 531 includes a corresponding capacitor pattern among the plurality of capacitor patterns 531e and a corresponding dielectric member among the plurality of dielectric members 531d. The plurality of capacitor elements 531 share a capacitor plate 531p. The plurality of capacitor patterns 531e may have the same area. In this case, the plurality of capacitor elements 531 have the same capacitance. In another embodiment, the plurality of capacitor elements 531 may have different capacitances.

[0067] The matching circuit 34 of the coupler 30C further includes a plurality of relays 71. In the coupler 30C, the plurality of relays 71 have the same configuration as the plurality of relays 71 in the coupler 30B. In the coupler 30C, the plurality of relays 71 are provided on a printed circuit board 531b. In the coupler 30C, a first contact of a relay switch of each of the plurality of relays 71 is connected to a corresponding one of the plurality of capacitor patterns 531e. In the coupler 30C, a second contact of a relay switch of each of the plurality of relays 71 is connected to a ground pattern 531g provided on the back surface of the printed circuit board 531b. The ground pattern 531g is connected to the bottom of the housing 30h, i.e., to ground, via a plurality of metal supports 53sp.

[0068] In the coupler 30C, the drive circuit 34d is connected to the relay coils 71c of the multiple relays 71 via the connector 53cn. 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 53 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 30C, the capacitance of the capacitor 53 can be adjusted by adjusting the state (open or closed) of the relay switches 71s of the multiple relays 71.

[0069] In addition, in coupler 30C, matching circuit 34 includes inductor 63 as inductor 60. Inductor 63 is configured with an inductor plate, which is a conductive plate made of a metal such as copper. The inductor plate extends horizontally above printed circuit board 531b. The inductor plate is connected to connection point 30s via metal support 30sp.

[0070] 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 30C, 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 63.

[0071] In the coupler 30C, the plurality of capacitor elements 531 are arranged in one or more columns. However, the plurality of capacitor elements 531 may be arranged in the circumferential direction around an axis extending vertically from the connection point 30s. The plurality of capacitor elements 531 may also 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 531.

[0072] In another embodiment, power supply 20p may be located radially outward from power supply 20p at a position where the load impedance is 50Ω. That is, the radial distance from axis AX to power supply 20p may be longer than r50. In this case, only capacitor 50 in variable reactance unit 36 ​​of the coupler of the plasma processing apparatus may have a variable reactance, and variable reactance unit 36 ​​may also have inductor 60. Capacitor 50 may be any of the various capacitors disclosed in this specification, such as capacitors 51 to 53.

[0073] In yet another embodiment, power supply 20p may be located radially inward relative to the position where the load impedance from power supply 20p is 50 Ω. That is, the radial distance from axis AX to power supply 20p may be shorter than the above-mentioned r50. In this case, in the coupler of the plasma processing apparatus, only inductor 60 may have a variable reactance.

[0074] Various exemplary embodiments of an inductor 60 having a variable inductance and exemplary embodiments of a coupler having such an inductor are described below.

[0075] Please refer to FIG. 11. FIG. 11 is a diagram illustrating an inductor according to one embodiment that can be employed in couplers according to various exemplary embodiments. The inductor 64 shown in FIG. 11 can be employed as the inductor of the variable reactance section of couplers according to various exemplary embodiments. The inductor 64 includes a coil 64ic, a core 64mc (magnetic core), and an insulating cover 64is. The coil 64ic is formed from a metal such as copper and is wound around the core 64mc. The insulating cover 64is is formed from an epoxy resin or the like and is disposed between the coil 64ic and the core 64mc so as to cover the core 64mc.

[0076] One end of the coil 64ic is connected to the connection point 30s. The other end of the coil 64ic may be connected to ground via a capacitor. A current source 64ip is connected to the other end of the coil 64ic. In this case, the control circuit 34c controls the current source 64ip to adjust the DC current supplied to the coil 64ic. When current is supplied to the coil 64ic, the core 64mc is excited, and the magnetic permeability of the core 64mc changes due to the nonlinearity of the BH curve of the core 64mc. Therefore, the inductance of the inductor 64 can be controlled by controlling the DC current supplied from the current source 64ip to the coil 64ic. The power supply control unit 24c notifies the control circuit 34c of an inductance setting value set to reduce the power level of the reflected wave. The control circuit 34c adjusts the DC current supplied from the current source 64ip to the coil 64ic in accordance with the notified setting value.

[0077] Reference will now be made to Figures 12 and 13. Figure 12 is a cross-sectional view showing a coupler according to yet another exemplary embodiment. Figure 13 is a cross-sectional view taken along line XIII-XIII in Figure 12. Figure 13 shows the structure of a longitudinal cross section of a coupler according to yet another exemplary embodiment. Below, a coupler 30D shown in Figures 12 and 13 will be described from the perspective of differences from coupler 30A.

[0078] The coupler 30D 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 is a microstrip line. The microstrip line has the constant characteristic impedance described above.

[0079] In the coupler 30D, 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.

[0080] In the coupler 30D, 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 30D has a configuration similar to that of the relay 71 in the coupler 30B described above. A 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. A 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. 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.

[0081] In the matching circuit 34 of the coupler 30D, the driver circuit 34d is connected to the relay coils 71c of the multiple relays 71 via a 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 a 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 30D, the inductance of the inductor 65 can be adjusted by setting the state of the relay switches 71s of the multiple relays 71.

[0082] FIG. 14 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. 14 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. Each of the relay switches 71s of relays RL1-RL4 provides a different inductance L when in the closed state. As a result, as shown in the table in FIG. 14, 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.

[0083] 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 Fig. 15. Fig. 15 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.

[0084] As shown in FIG. 15 , 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. 15 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. 15 , 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.

[0085] 15, 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.

[0086] 15, the matching circuit 34 includes a drive circuit 34d and a control circuit 34c. The drive circuit 34d 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.

[0087] 15, the relay coils 71c of the relays 71 may be floating from the ground. In this case, each of the drive circuits 71d is connected to the transformer 71. T1 , a pulse generator 71p, and a DC voltage generating circuit 71g. T1Between the primary coil and ground, a 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.

[0088] 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.

[0089] 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.

[0090] The pulse current generated in the secondary coil is passed through the second diode 71 D2 via capacitor 71 CwWhen 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.

[0091] As shown in FIG. 15, the matching circuit 34 includes a common resistor 34 Ru (shunt resistor) and multiple resistors 34 Rd 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.

[0092] 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.

[0093] 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.

[0094] The matching circuit 34 also includes a common resistor 34 Rs (shunt resistor) may be further included. 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 It is connected to one end of the primary coil of the common resistor 34 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.

[0095] 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.

[0096] Various exemplary embodiments included in the present disclosure are now described in [E1] to [E17] below.

[0097] [E1] 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 coupler including an input for the high frequency power, the coupler having a variable impedance and connected between the high frequency power source and the resonator; a transmission line having a constant characteristic impedance, the transmission line extending from the input portion through the coupler to the power supply portion; A plasma processing apparatus comprising:

[0098] [E2] The plasma processing apparatus according to E1, wherein the characteristic impedance is 50Ω.

[0099] [E3] The coupler comprises: a connection point provided on the transmission line; a variable reactance section including a capacitor and / or an inductor and connected between the connection point and ground; Including, The position of the connection point is determined so that a change in a reflection coefficient corresponding to the impedance seen from the connection point to the load side when the reactance of the variable reactance section is changed and a change in the reflection coefficient when the frequency of the high frequency power is changed are orthogonal to each other in a coordinate system having a real axis and an imaginary axis that are orthogonal to each other. The plasma processing apparatus according to E1 or E2.

[0100] [E4] 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; Including, The waveguide is an upper portion constituting the uppermost layer of the layer structure and having an upper end at the outer periphery; a lower portion constituting the lowest layer of the layer structure and including a lower end connected to the introduction portion; and configured to resonate an electromagnetic wave propagating through the waveguide between the upper end and the lower end, the power supply portion is disposed inside and above the upper end, The position of the connection point satisfies the following formula (1):

number

[0101] [E5] The plasma processing apparatus according to E4, wherein the power supply unit is provided at a radial position where the impedance on the load side from the power supply unit is 50Ω.

[0102] [E6] The plasma processing apparatus according to E4, wherein the power supply unit is provided at a position outside a radial position where the impedance on the load side from the power supply unit is 50Ω.

[0103] [E7] The plasma processing apparatus according to E4, wherein the power supply unit is provided at a position inside a radial position where the impedance on the load side from the power supply unit is 50Ω.

[0104] [E8] The plasma processing apparatus according to any one of E3 to E6, wherein the capacitor of the variable reactance section is a variable capacitor.

[0105] [E9] the capacitor has a variable capacitance; a plurality of capacitor elements connected in parallel to the connection point; a plurality of relays, each including a relay switch connected between a corresponding one of the plurality of capacitor elements and ground; Including, The plasma processing apparatus according to any one of E3 to E6.

[0106] [E10] 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 plasma processing apparatus according to E9.

[0107] [E11] The plurality of capacitor elements include: 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; The plasma processing apparatus of E10, comprising:

[0108] [E12] The plasma processing apparatus described in any one of E3 to E5 and E7, wherein the inductor includes a conductor pattern extending from one end connected to the connection point and shorted to ground, and the length of the conductor pattern from the one end to the portion shorted to ground is configured to be changeable.

[0109] [E13] The inductor is an inductor pattern which is the conductor pattern; a short-circuiting member that shorts the inductor pattern to ground; a length of the inductor pattern between the connection point and a point where the short-circuiting member contacts the inductor pattern, the length being changeable. The plasma processing apparatus according to E12.

[0110] [E14] the inductor includes a conductive plate; The conductor plate is connected to the connection point via a connection member extending from the connection point to the conductor plate, and is configured to be positionally changeable so as to vary the electrical length between the connection point and the conductor plate. The plasma processing apparatus according to any one of E3 to E5 and E7.

[0111] [E15] The inductor is A magnetic core and a coil wound around the front core; a variable current source connected to the coil; The plasma processing apparatus according to any one of E3 to E5 and E7, comprising:

[0112] [E16] The inductor is A conductor pattern; a plurality of relays, each including a relay switch, connected in parallel between the conductor pattern and ground; Including, the relay switches of the plurality of relays are connected to the conductor pattern at positions with different electrical lengths from the connection point so that the inductance of the inductor can be changed in multiple stages with the same inductance change amount; The plasma processing apparatus according to any one of E3 to E5 and E7.

[0113] [E17] each relay switch of the plurality of relays includes a respective first contact and a respective second contact connected to the ground; The plasma processing apparatus comprises: a common resistor connected to a DC power supply; a plurality of resistors respectively connected between the common resistor and each of the first contacts; a detector configured to detect a fault in the plurality of relays based on a voltage across the common resistor; The plasma processing apparatus according to any one of E9 to E11 and E16, further comprising:

[0114] 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]

[0115] 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.

Claims

1. 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 coupler including an input for the high frequency power, the coupler having a variable impedance and connected between the high frequency power source and the resonator; a transmission line having a constant characteristic impedance, the transmission line extending from the input portion through the coupler to the power supply portion; A plasma processing apparatus comprising:

2. 2. The plasma processing apparatus according to claim 1, wherein the characteristic impedance is 50 ohms.

3. The coupler comprises: a connection point provided on the transmission line; a variable reactance section including a capacitor and / or an inductor and connected between the connection point and ground; Including, The position of the connection point is determined so that a change in a reflection coefficient corresponding to the impedance seen from the connection point to the load side when the reactance of the variable reactance section is changed and a change in the reflection coefficient when the frequency of the high frequency power is changed are orthogonal to each other in a coordinate system having a real axis and an imaginary axis that are orthogonal to each other. The plasma processing apparatus according to claim 1 .

4. 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; Including, The waveguide is an upper portion constituting the uppermost layer of the layer structure and having an upper end at the outer periphery; a lower portion constituting the lowest layer of the layer structure and including a lower end connected to the introduction portion; and configured to resonate an electromagnetic wave propagating through the waveguide between the upper end and the lower end, the power supply portion is disposed inside and above the upper end, The position of the connection point satisfies the following formula (1): [Equation 1] Here, L ｒ is the length along the radial direction between the power supply part and the upper end, and L ｅ is the electrical length between the power supply and the connection point, and λ ｇｒ is the wavelength of the electromagnetic wave in the waveguide of the resonator between the feed and the upper end, and λ ｇｅ is the wavelength of the electromagnetic wave between the power supply and the connection point, and n is 0 or a positive integer. The plasma processing apparatus according to claim 3 .

5. 5. The plasma processing apparatus according to claim 4, wherein the power supply unit is provided at a radial position where an impedance on the load side from the power supply unit is 50[Omega].

6. 5. The plasma processing apparatus according to claim 4, wherein the power supply unit is provided at a position outside a position in the radial direction where an impedance on the load side from the power supply unit becomes 50[Omega].

7. 5. The plasma processing apparatus according to claim 4, wherein the power supply unit is provided at a position inside a radial position where an impedance on the load side from the power supply unit is 50[Omega].

8. 7. The plasma processing apparatus according to claim 3, wherein the capacitor of the variable reactance section is a variable capacitor.

9. the capacitor has a variable capacitance; a plurality of capacitor elements connected in parallel to the connection point; a plurality of relays, each including a relay switch connected between a corresponding one of the plurality of capacitor elements and ground; Including, The plasma processing apparatus according to any one of claims 3 to 6.

10. 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 plasma processing apparatus according to claim 9 .

11. 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; The plasma processing apparatus of claim 10 , comprising:

12. The plasma processing apparatus according to any one of claims 3 to 5 and 7, wherein the inductor includes a conductor pattern extending from one end connected to the connection point and shorted to ground, and the length of the conductor pattern from the one end to the portion shorted to ground is configured to be changeable.

13. The inductor is an inductor pattern which is the conductor pattern; a short-circuiting member that shorts the inductor pattern to ground; a length of the inductor pattern between the connection point and a point where the short-circuiting member contacts the inductor pattern, the length being changeable. The plasma processing apparatus according to claim 12 .

14. the inductor includes a conductive plate; The conductor plate is connected to the connection point via a connection member extending from the connection point to the conductor plate, and is configured to be positionally changeable so as to vary the electrical length between the connection point and the conductor plate.

8. The plasma processing apparatus according to claim 3, wherein the plasma processing apparatus is a plasma processing apparatus.

15. The inductor is A magnetic core and a coil wound around the front core; a variable current source connected to the coil; 8. The plasma processing apparatus according to claim 3, further comprising:

16. The inductor is A conductor pattern; a plurality of relays, each including a relay switch, connected in parallel between the conductor pattern and ground; Including, the relay switches of the plurality of relays are connected to the conductor pattern at positions with different electrical lengths from the connection point so that the inductance of the inductor can be changed in multiple stages with the same inductance change amount; 8. The plasma processing apparatus according to claim 3, wherein the plasma processing apparatus is a plasma processing apparatus.

17. each relay switch of the plurality of relays includes a respective first contact and a respective second contact connected to the ground; The plasma processing apparatus comprises: a common resistor connected to a DC power supply; a plurality of resistors respectively connected between the common resistor and each of the first contacts; a detector configured to detect a fault in the plurality of relays based on a voltage across the common resistor; The plasma processing apparatus of claim 9 , further comprising:

18. each relay switch of the plurality of relays includes a respective first contact and a respective second contact connected to the ground; The plasma processing apparatus comprises: a common resistor connected to a DC power supply; a plurality of resistors respectively connected between the common resistor and each of the first contacts; a detector configured to detect a fault in the plurality of relays based on a voltage across the common resistor; The plasma processing apparatus of claim 16 further comprising:

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