Plasma processing device and plasma measurement method

Abstract

To provide a plasma processing device capable of quantitatively evaluating plasma generated via a resonator array structure, in the vicinity thereof, and a plasma measurement method.SOLUTION: A plasma processing device comprises: a processing container which provides a processing space; an electromagnetic wave generator which supplies an electromagnetic wave and generates plasma in the processing space; a first dielectric which is provided while opposing a first face to the processing space; an electromagnetic wave supply section which is configured to supply the electromagnetic wave to the processing space via the first dielectric; and a resonator array structure which is positioned in the processing container along the first face of the first dielectric. The resonator array structure includes a plurality of resonators which can be resonated with a magnetic field component of the electromagnetic wave and of which size is smaller than a wavelength of the electromagnetic wave. The plurality of resonators has a structure in which C-shaped ring members composed of conductors are laminated on one face of a dielectric plate. At least one of the C-shaped ring members is used also as a probe for measuring information on plasma.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to a plasma processing apparatus and a plasma measurement method. [Background technology]

[0002] <000000> The plasma processing apparatus disclosed in Patent Document 1 comprises a processing vessel, an electromagnetic wave generator, and a resonator array structure. The processing vessel provides a processing space. The electromagnetic wave generator generates electromagnetic waves for plasma excitation that are supplied to the processing space. The resonator array structure is formed by arranging a plurality of resonators that are capable of resonating with the magnetic field component of the electromagnetic wave and whose size is smaller than the wavelength of the electromagnetic wave, and is located inside the processing vessel. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2023 / 032725 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] This disclosure provides a plasma processing apparatus and a plasma measurement method that can quantitatively evaluate plasma generated through a resonator array structure in its vicinity. [Means for solving the problem]

[0005] A plasma processing apparatus according to an aspect of the present disclosure includes a processing container that provides a processing space, an electromagnetic wave generator configured to supply electromagnetic waves and generate plasma in the processing space, a first dielectric provided with a first surface facing the processing space, an electromagnetic wave supply unit configured to supply electromagnetic waves to the processing space through the first dielectric, and a resonator array structure located along the first surface of the first dielectric in the processing container. The resonator array structure includes a plurality of resonators that can resonate with the magnetic field component of the electromagnetic wave and have a size smaller than the wavelength of the electromagnetic wave. The plurality of resonators have a structure in which a C-shaped ring member made of a conductor is laminated on one surface of a dielectric plate. At least one of the C-shaped ring members also serves as a probe for measuring plasma information.

Advantages of the Invention

[0006] According to the present disclosure, the plasma generated through the resonator array structure can be quantitatively evaluated in its vicinity.

Brief Description of the Drawings

[0007]

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Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments of the disclosed plasma processing apparatus and plasma measurement method will be described in detail based on the drawings. Note that the disclosed technology is not limited by the following embodiments.

[0009] By the way, in a plasma processing apparatus using microwaves for plasma excitation, the power of the microwaves supplied into the processing chamber may be increased in order to increase the electron density of the plasma. The higher the power of the microwaves supplied into the processing chamber, the higher the electron density of the plasma can be increased.

[0010] Here, it is known that when the electron density of the plasma reaches a certain upper limit value by increasing the power of the microwaves supplied into the processing chamber, the dielectric constant of the space in the processing chamber becomes negative. This upper limit value of the electron density is appropriately referred to as the "cutoff density". Also, the refractive index is known as an index indicating whether microwaves propagate through space or not. The refractive index N is expressed by the following formula (1). N = √ε√μ ···(1) However, ε: dielectric constant, μ: magnetic permeability

[0011] Since the magnetic permeability is generally positive, when the dielectric constant of the space in the processing chamber becomes negative, according to the above formula (1), the refractive index of the space in the processing chamber becomes a pure imaginary number. As a result, the microwaves are attenuated and cannot propagate through the space in the processing chamber. Thus, when the electron density of the plasma reaches the cutoff density, in the space in the processing chamber, the microwaves cannot propagate, so the power of the microwaves is not sufficiently absorbed by the plasma. As a result, there is a problem that the high-density formation of the plasma generated in the processing chamber over a wide range is inhibited.

[0012] Therefore, it is expected that the high-density formation of the plasma over a wide range can be realized and the plasma generated through a resonator array structure (hereinafter also referred to as a metamaterial) can be quantitatively evaluated in its vicinity.

[0013] [Configuration of Plasma Processing Apparatus] Figure 1 is a schematic cross-sectional view showing an example of the configuration of a plasma processing apparatus according to one embodiment of the present disclosure. The plasma processing apparatus 1 comprises a main apparatus body 10 and a control device 11. The main apparatus body 10 comprises a processing vessel 12, a stage 14, a microwave output device (an example of an electromagnetic wave generator) 16, an antenna 18, a dielectric window 20, a resonator array structure 100, and a measuring unit 220.

[0014] The processing container 12 is formed in a substantially cylindrical shape from, for example, aluminum whose surface has been anodized, and provides a substantially cylindrical processing space S inside. The processing container 12 is grounded for safety. The processing container 12 also has a side wall 12a and a bottom 12b. The central axis of the side wall 12a is defined as axis Z. The bottom 12b is provided on the lower end side of the side wall 12a. An exhaust port 12h for exhaust is provided in the bottom 12b. The upper end of the side wall 12a is open. The inner wall surface of the side wall 12a faces the processing space S. That is, the side wall 12a is provided with its inner wall surface facing the processing space S.

[0015] An opening 12c is formed in the side wall 12a for loading and unloading the object to be processed WP. The opening 12c is opened and closed by a gate valve G.

[0016] A dielectric window 20 is provided at the upper end of the side wall 12a, closing the opening at the upper end of the side wall 12a from above. The lower surface (an example of the first surface) 20a of the dielectric window (an example of the first dielectric) 20 faces the processing space S. That is, the dielectric window 20 is provided with its lower surface 20a facing the processing space S. An O-ring 19 is placed between the dielectric window 20 and the upper end of the side wall 12a.

[0017] Stage 14 is housed within the processing container 12. Stage 14 is positioned to face the dielectric window 20 in the direction of axis Z. The space between stage 14 and the dielectric window 20 is the processing space S. The object to be processed WP is placed on top of stage 14.

[0018] The stage 14 has a base 14a and an electrostatic chuck 14c. The base 14a is formed in a substantially disk shape from a conductive material such as aluminum. The base 14a is disposed in the processing vessel 12 such that the central axis of the base 14a substantially coincides with the axis Z.

[0019] The base 14a is supported by a cylindrical support portion 48 formed of an insulating material and extending in the direction of the axis Z. A conductive cylindrical support portion 50 is provided on the outer periphery of the cylindrical support portion 48. The cylindrical support portion 50 extends from the bottom 12b of the processing vessel 12 toward the dielectric window 20 along the outer periphery of the cylindrical support portion 48. An annular exhaust passage 51 is formed between the cylindrical support portion 50 and the side wall 12a.

[0020] An annular baffle plate 52 having a plurality of through-holes formed in the thickness direction is provided above the exhaust passage 51. The exhaust port 12h described above is provided below the baffle plate 52. An exhaust device 56 having a vacuum pump such as a turbo molecular pump and an automatic pressure control valve or the like is connected to the exhaust port 12h via an exhaust pipe 54. The exhaust device 56 can reduce the processing space S to a desired degree of vacuum.

[0021] The base 14a functions as a high-frequency electrode. An RF bias high-frequency power source 58 is electrically connected to the base 14a via a power supply rod 62 and a matching unit 60. The high-frequency power source 58 supplies bias power of a predetermined frequency (for example, 13.56 MHz) suitable for controlling the energy of ions drawn into the workpiece WP to the base 14a via the matching unit 60 and the power supply rod 62.

[0022] The matching unit 60 houses a matcher for matching between the impedance on the high-frequency power source 58 side and the impedance on the load side mainly including the electrode, plasma, and processing vessel 12. The matcher includes a blocking capacitor for self-bias generation.

[0023] On the upper surface of the base 14a, an electrostatic chuck 14c is provided. The electrostatic chuck 14c adsorbs and holds the workpiece WP by electrostatic force. The electrostatic chuck 14c has a substantially disk-shaped outer profile and includes an electrode 14d, an insulating film (dielectric film) 14e, and an insulating film (dielectric film) 14f. The electrostatic chuck 14c is arranged on the upper surface of the base 14a such that the central axis of the electrostatic chuck 14c substantially coincides with the axis Z. The electrode 14d of the electrostatic chuck 14c is formed of a conductive film and is provided between the insulating film 14e and the insulating film 14f. A DC power supply 64 is electrically connected to the electrode 14d via a covered wire 68 and a switch 66. The electrostatic chuck 14c can adsorb and hold the workpiece WP on its upper surface by the electrostatic force generated by the DC voltage applied from the DC power supply 64. The upper surface of the electrostatic chuck 14c is a placement surface on which the workpiece WP is placed and faces the processing space S. That is, the electrostatic chuck 14c is provided with its upper surface, which is the placement surface, facing the processing space S. Also, an edge ring 14b is provided on the base 14a. The edge ring 14b is arranged so as to surround the workpiece WP and the electrostatic chuck 14c. The edge ring 14b is sometimes called a focus ring.

[0024] Inside the base 14a, a flow path 14g is provided. A refrigerant is supplied to the flow path 14g via a pipe 70 from a chiller unit (not shown). The refrigerant supplied to the flow path 14g is returned to the chiller unit via a pipe 72. By circulating the refrigerant whose temperature is controlled by the chiller unit inside the flow path 14g of the base 14a, the temperature of the base 14a is controlled. By controlling the temperature of the base 14a, the temperature of the workpiece WP on the electrostatic chuck 14c is controlled via the electrostatic chuck 14c on the base 14a.

[0025] Also, a pipe 74 for supplying a heat transfer gas such as He gas is formed in the stage 14 between the upper surface of the electrostatic chuck 14c and the back surface of the workpiece WP.

[0026] The microwave output device 16 outputs microwaves (an example of electromagnetic waves) to excite the processing gas supplied into the processing container 12. The microwave output device 16 allows adjustment of the microwave frequency, power, and bandwidth. For example, the microwave output device 16 can generate a single-frequency microwave by setting the microwave bandwidth to approximately 0. The microwave output device 16 can also generate a microwave containing multiple frequency components belonging to a predetermined frequency bandwidth (hereinafter referred to as "broadband microwave" as appropriate). The power of these multiple frequency components may be the same, or only the central frequency component within the bandwidth may have a higher power than the other frequency components. The microwave output device 16 can adjust the microwave power within a range of, for example, 0W to 5000W. The microwave output device 16 can adjust the microwave frequency or the central frequency of the broadband microwave within a range of, for example, 2.3GHz to 2.5GHz, and can adjust the bandwidth of the broadband microwave within a range of, for example, 0MHz to 100MHz. Furthermore, the microwave output device 16 can adjust the frequency pitch (carrier pitch) of multiple frequency components of the broadband microwave, for example, within a range of 0 to 25 kHz.

[0027] The device body 10 also includes a waveguide 21, a tuner 26, a mode converter 27, and a coaxial waveguide 28. The output section of the microwave output device 16 is connected to one end of the waveguide 21. The other end of the waveguide 21 is connected to the mode converter 27. The waveguide 21 is, for example, a rectangular waveguide. The waveguide 21 is provided with a tuner 26. The tuner 26 has a movable plate 26a and a movable plate 26b. By adjusting the amount of protrusion of the movable plates 26a and 26b relative to the internal space of the waveguide 21, the impedance of the microwave output device 16 and the impedance of the load can be matched.

[0028] The mode converter 27 converts the mode of the microwave output from the waveguide 21 and supplies the microwave after mode conversion to the coaxial waveguide 28. The coaxial waveguide 28 includes an outer conductor 28a and an inner conductor 28b. The outer conductor 28a and the inner conductor 28b have a substantially cylindrical shape. The outer conductor 28a and the inner conductor 28b are arranged above the antenna 18 such that the central axes of the outer conductor 28a and the inner conductor 28b substantially coincide with the axis Z. The coaxial waveguide 28 transmits the microwave whose mode has been converted by the mode converter 27 to the antenna 18.

[0029] The antenna 18 supplies microwaves to the processing space S. The antenna 18 is an example of an electromagnetic wave supply unit. The antenna 18 is provided on the upper surface 20b of the dielectric window 20 and supplies microwaves to the processing space S through the dielectric window 20. The antenna 18 includes a slot plate 30, a dielectric plate 32, and a cooling jacket 34. The slot plate 30 is formed in a substantially disk shape from a conductive metal. The slot plate 30 is provided on the upper surface 20b of the dielectric window 20 such that the central axis of the slot plate 30 coincides with the axis Z. A plurality of slot holes are formed in the slot plate 30. The plurality of slot holes constitute, for example, a plurality of slot pairs. Each of the plurality of slot pairs includes two slot holes in the shape of elongated holes extending in directions intersecting each other. The plurality of slot pairs are arranged along one or more concentric circles around the central axis of the slot plate 30. Further, a through hole 30d through which a conduit 36 described later can pass is formed in the central portion of the slot plate 30.

[0030] The dielectric plate 32 is formed in a substantially disk shape from a dielectric material such as quartz. The dielectric plate 32 is provided on the slot plate 30 such that the central axis of the dielectric plate 32 substantially coincides with the axis Z. The cooling jacket 34 is provided on the dielectric plate 32. The dielectric plate 32 is provided between the cooling jacket 34 and the slot plate 30.

[0031] The surface of the cooling jacket 34 has conductivity. A flow path 34a is formed inside the cooling jacket 34. Refrigerant is supplied to the flow path 34a from a chiller unit (not shown). The lower end of the outer conductor 28a is electrically connected to the upper surface of the cooling jacket 34. Also, the lower end of the inner conductor 28b is electrically connected to the slot plate 30 through an opening formed in the central portions of the cooling jacket 34 and the dielectric plate 32.

[0032] The microwave propagated in the coaxial waveguide 28 propagates in the dielectric plate 32 and is radiated from the plurality of slot holes of the slot plate 30 to the processing space S through the dielectric window 20.

[0033] The resonator array structure 100 is formed by arranging a plurality of resonators that can resonate with the magnetic field component of the microwave and have a size smaller than the wavelength of the microwave, and is located in the processing container 12.

[0034] Since the resonator array structure 100 is located in the processing container 12, the microwave supplied to the processing space S by the antenna 18 and the plurality of resonators of the resonator array structure 100 can be resonated. By the resonance between the microwave and the plurality of resonators, the microwave can be efficiently supplied to the processing space S of the processing container 12 and the magnetic permeability of the processing space S can be made negative. When the magnetic permeability of the processing space S is negative, even when the electron density of the plasma generated in the processing space S reaches the cutoff density and the dielectric constant of the processing space S is negative, the refractive index becomes a real number according to the above formula (1), so the microwave can propagate in the processing space S. As a result, even when the electron density of the plasma generated in the processing space S reaches the cutoff density, the microwave can propagate beyond the skin depth of the plasma and the power of the microwave is efficiently absorbed by the plasma. As a result, a high-density plasma can be generated over a wide range beyond the skin depth of the plasma. That is, according to the plasma processing apparatus 1 according to the present embodiment, by positioning the resonator array structure 100 in the processing container 12, high-density plasma can be realized over a wide range.

[0035] Here, referring to FIGS. 1 and 2, the detailed configuration of the resonator array structure 100 will be described. FIG. 2 is a plan view showing an example of the configuration of the dielectric window 20 and the resonator array structure 100 according to the present embodiment as viewed from below. In FIG. 2, the lower surface 20a of the dielectric window 20 is shown in a disk shape.

[0036] As shown in FIGS. 1 and 2, the resonator array structure 100 is arranged along the lower surface 20a of the dielectric window 20.

[0037] The resonator array structure 100 is formed by arranging a plurality of resonators 101 that can resonate with the magnetic field component of microwaves and have a size smaller than the wavelength of microwaves in a lattice pattern. Specifically, the plurality of resonators 101 includes at least one of the resonators 101A and 101B shown in FIGS. 3 and 4. Also, at least one of the plurality of resonators 101 includes the resonator 101C shown in FIG. 7. Each of the plurality of resonators 101 constitutes a series resonance circuit composed of a capacitor equivalent element and an inductor equivalent element. The series resonance circuit is realized by patterning a conductor on a plane.

[0038] FIG. 3 is a diagram showing an example of the configuration of the card-shaped resonator 101A according to the present embodiment. The card-shaped resonator 101A shown in FIG. 3 has a structure in which two C-shaped ring members 111A made of a conductor and facing each other and concentric are laminated on one surface of a dielectric plate 112A. Capacitor equivalent elements are formed on the opposing surfaces of the inner ring member 111A and the outer ring member 111A and at both ends of each ring member 111A, and an inductor equivalent element is formed along each ring member 111A. Thereby, the resonator 101A can constitute a series resonance circuit.

[0039] FIG. 4 is a diagram showing an example of the configuration of the card-shaped resonator 101B according to the present embodiment. The card-shaped resonator 101B shown in FIG. 4 is composed of two C-shaped ring members 111B made of a conductor, and has a structure in which a dielectric plate 112B is disposed between the ring members 111B that are adjacent to each other in opposite directions. That is, in the resonator 101B, the dielectric plate 112B is sandwiched between two C-shaped ring members 111B that are opposite to each other. Capacitor equivalent elements are formed on the opposing surfaces of the two C-shaped ring members 111B and at both ends of each ring member 111B, and coil equivalent elements are formed along each ring member 111B. Thereby, the resonator 101B can constitute a series resonance circuit. Note that the card-shaped resonator 101B can also be expressed as being formed in a card shape for each set of two C-shaped ring members 111B.

[0040] In the resonator 101B shown in FIG. 4, the number of arranged ring members 111B (hereinafter, also appropriately referred to as the “number of layers”) is 2, but the number of layers of the ring members 111B may be larger than 2. FIG. 5 is a diagram showing another example of the configuration of the card-shaped resonator 101B according to the present embodiment. The resonator 101B shown in FIG. 5 is composed of N (N≧2) C-shaped ring members 111B made of a conductor, and has a structure in which a dielectric plate 112B is disposed between the ring members 111B that are adjacent to each other in opposite directions. Even with such a structure, the resonator 101B can constitute a series resonance circuit.

[0041] Also, an insulating film may be formed on each of the plurality of resonators 101. FIG. 6 is a diagram showing an example of a cross section of the card-shaped resonator 101B according to the present embodiment. FIG. 6 shows a side cross section of the resonator 101B shown in FIG. 4. An insulating film (an example of a second dielectric) 113 is formed on the surface of the resonator 101B. The material of the film 113 is, for example, ceramic. The thickness of the film 113 is, for example, within a range of 0.001 mm to 2 mm. By forming the insulating film 113 on each of the plurality of resonators 101, abnormal discharge in each of the plurality of resonators 101 can be suppressed.

[0042] Furthermore, in each of the plurality of resonators 101, at least one of the C-shaped ring members may also serve as a probe for measuring plasma information. Conventionally, for example, plasma has been measured by a probe provided on the side wall of a chamber. However, in the resonator array structure 100, since plasma is locally generated for each cell described later, it is difficult to quantitatively monitor how much these plasmas can be controlled. Therefore, in the present embodiment, by making the C-shaped ring member also serve as a probe, the plasma generated through the resonator array structure 100 is quantitatively monitored in the vicinity thereof.

[0043] FIG. 7 is a diagram showing an example of the configuration of a card-shaped resonator 101C that also serves as a probe according to the present embodiment. The resonator 101C shown in FIG. 7 is composed of two C-shaped ring members 111C made of a conductor, and has a structure in which a dielectric plate 112C is disposed between the ring members 111C that are adjacent to each other in opposite directions. That is, in the resonator 101C, the dielectric plate 112C is sandwiched by two C-shaped ring members 111C facing each other. Capacitor equivalent elements are formed at the opposing surfaces of the two C-shaped ring members 111C and at both ends of each ring member 111C, and coil equivalent elements are formed along each ring member 111C. Thereby, the resonator 101C can constitute a series resonance circuit. In addition, wirings 114C are respectively connected to the two C-shaped ring members 111C. The wiring 114C is disposed up to the end face of the resonator 101C, and can be connected to the wiring 122 on the base plate 120 side, which will be described later, at the end face. Note that the card-shaped resonator 101C can also be expressed as being formed in a card shape for each set of two C-shaped ring members 111C. Further, the resonator 101C corresponds to the resonator 101B provided with the wiring 114C.

[0044] FIG. 8 is a diagram showing an example of a cross section of a card-shaped resonator 101C that also serves as a probe according to the present embodiment. In FIG. 8, a side cross section of the resonator 101C shown in FIG. 7 is shown. An insulating film (an example of a second dielectric) 113C is formed on the surface of the resonator 101C. The material of the film 113C is, for example, ceramic. The thickness of the film 113C is, for example, within the range of 0.001 mm to 2 mm. Here, when the thickness of the film 113C is defined as thickness t1 and the thickness of the dielectric plate 112C is defined as thickness t2, in the resonator 101C, the thicknesses of the dielectric plate 112C and the film 113C are determined so that the relationship of thickness t1 << thickness t2 holds. Also, the thickness t2 of the dielectric plate 112C is preferably 100 times or more the thickness t1 of the film 113C. Thereby, the two C-shaped ring members 111C each function as an insulating probe for measuring the plasma on the film 113C side to which the wiring 114C is connected. That is, a dielectric plate 112C is sandwiched between the two C-shaped ring members 111C of the resonator 101C and is much thicker than the film 113C, so the impedance between the two C-shaped ring members 111C becomes high. That is, the influence of the C-shaped ring member 111C as a probe function on the dielectric plate 112C side becomes small.

[0045] In other words, the C-shaped ring member 111C is formed on both surfaces of the dielectric plate 112C and is covered with a film 113C which is a second dielectric. Also, the thickness of the dielectric plate 112C between the C-shaped ring members 111C formed on both surfaces of the dielectric plate 112C is thicker than the thickness of the film 113C which is a second dielectric covering the C-shaped ring member 111C. Also, the thickness of the dielectric plate 112C is 100 times or more the thickness of the film 113C which is a second dielectric.

[0046] Refer to FIG. 1 again. Inside the inner conductor 28b of the coaxial waveguide 28, a conduit 36 is provided. A through-hole 30d through which the conduit 36 can pass is formed in the central portion of the slot plate 30. The conduit 36 extends through the inside of the inner conductor 28b and is connected to the gas supply unit 38.

[0047] The gas supply unit 38 supplies a processing gas for processing the workpiece WP to the conduit 36. The gas supply unit 38 includes a gas supply source 38a, a valve 38b, and a flow controller 38c. The gas supply source 38a is a supply source of the processing gas. The valve 38b controls the supply and stop of the processing gas from the gas supply source 38a. The flow controller 38c is, for example, a mass flow controller or the like, and controls the flow rate of the processing gas from the gas supply source 38a.

[0048] Further, the apparatus main body 10 includes an injector 41. The injector 41 supplies the gas from the conduit 36 to the through-hole 20h formed in the dielectric window 20. The gas supplied to the through-hole 20h of the dielectric window 20 is injected into the processing space S and excited by the microwave supplied from the antenna 18 to the processing space S through the dielectric window 20. As a result, the processing gas is plasmaized in the processing space S, and the workpiece WP is processed by ions and radicals contained in the plasma.

[0049] The apparatus main body 10 further includes a measurement unit 220. The measurement unit 220 is connected via a C-shaped ring member 111C that also serves as an insulation probe and a wiring 222 (including wirings 122 and 114C to be described later). The measurement unit 220 includes a power supply unit that applies an alternating voltage to the C-shaped ring member 111C via the wiring 222, the wiring 122 to be described later, and the wiring 114C, and an ammeter that measures the current value flowing through the C-shaped ring member 111C. The power supply unit is controlled to apply, for example, an alternating voltage with a low frequency of 100 kHz or less and a low voltage of about several volts to the C-shaped ring member 111C. That is, the alternating voltage applied from the power supply unit is a frequency and voltage that do not affect the operation of the resonator array structure 100. Note that the measurement unit 220 may be provided with a low-pass filter, a band-stop filter, etc. to suppress the influence of the electromagnetic wave supplied from the microwave output device 16.

[0050] Based on the measured current value, the measurement unit 220 calculates the electron temperature Te and the electron density ne. The measurement unit 220 outputs the calculated electron temperature Te and electron density ne to the control device 11. Note that the measurement unit 220 may output the measured current value to the control device 11, and the control device 11 may calculate the electron temperature Te and the electron density ne. Further, the calculated electron temperature Te and electron density ne can be used for feedback control of the microwave output device 16. For example, since the resonator 101 has a sensitive responsiveness to the frequency of the electromagnetic wave, the control device 11 controls the microwave output device 16 to adjust the frequency of the electromagnetic wave while checking the calculated electron temperature Te and electron density ne, that is, the state of the plasma.

[0051] The control device 11 includes a processor, a memory, and an input / output interface. Programs, process recipes, etc. are stored in the memory. The processor reads out and executes a program from the memory, and based on the process recipe stored in the memory, it comprehensively controls each part of the apparatus main body 10 via the input / output interface.

[0052] For example, when plasma is generated in the processing space S, the control device 11 controls the microwave supplied to the processing space S by the antenna 18 and the plurality of resonators 101 to resonate in a target frequency band higher than the resonance frequencies of the plurality of resonators 101. Here, the resonance frequency is, for example, the frequency at which the transmission characteristic value (e.g., S21 value) of the plurality of resonators 101 becomes a minimum value.

[0053] FIG. 9 is a diagram showing an example of the relationship between the S21 value of a card-shaped resonator and the frequency of a microwave. When the frequency of the microwave supplied to the processing space S by the antenna 18 matches the resonance frequency fr (= approximately 2.35 GHz) of the plurality of resonators 101, the S21 values of the plurality of resonators 101 become minimum values, and resonance between the microwave and the plurality of resonators 101 occurs. The resonance between the microwave and the plurality of resonators 101 is maintained even in a predetermined frequency band (e.g., approximately 0.1 GHz) higher than the resonance frequency fr of the plurality of resonators 101. In a predetermined frequency band higher than the resonance frequency fr of the plurality of resonators 101, the resonance between the microwave and the plurality of resonators 101 can make both the permittivity and the permeability of the processing space S negative, and as can be seen from the above formula (1), microwave propagation in the processing space S becomes possible. The target frequency band of the present embodiment is set to a predetermined frequency band (e.g., approximately 0.1 GHz) higher than the resonance frequency fr of the plurality of resonators 101. The target frequency band is preferably, for example, within 0.05 times the resonance frequency fr of the plurality of resonators 101. In the measurement of the resonance frequency fr of the card-shaped resonator 101, it can be measured, for example, with a vector network analyzer in which a transmission / reception antenna is arranged in a direction parallel to the ring member 111B of the card-shaped resonator 101B.

[0054] Regarding the propagation of electromagnetic waves with respect to a plurality of resonators, the relationship between the resonance frequency and the refractive index, permittivity, and permeability has been reported by, for example, D.R. Smith, D.C. Vier, Th. Koschny, and C.M. Soukoulis et al. in "Electromagnetic parameter retrieval from inhomogeneous metamaterials" in "PHYSICAL REVIEW E 71, 036617 (2005)".

[0055] Thus, by resonating microwaves with a plurality of resonators 101 in a target frequency band higher than the resonance frequency fr of the plurality of resonators 101, even when the electron density of the plasma reaches the cutoff density, the propagation of microwaves can exceed the skin depth of the plasma. For this reason, the power of the microwaves can be efficiently absorbed by the plasma. As a result, a high-density plasma can be generated over a wide range exceeding the skin depth of the plasma. That is, according to the plasma processing apparatus 1 according to the present embodiment, in a target frequency band higher than the resonance frequency fr of the plurality of resonators 101, by resonating microwaves with the plurality of resonators 101, high-density plasma can be realized over a wide range.

[0056] [Details of the resonator array structure] Next, the details of the resonator array structure 100 will be described. As shown in FIG. 2, in the resonator array structure 100, card-shaped resonators 101 are arranged in a lattice pattern. In the following description, the resonator array structure 100 may be represented as the metamaterial 100, and the card-shaped resonator 101 may be represented as the meta-atom 101. In the example of FIG. 2, the meta-atoms 101 are arranged such that the cells surrounded by the meta-atoms 101 are formed in 5 columns in the X-axis direction and 5 rows in the Y-axis direction. That is, the meta-atoms 101 are arranged in 6 rows and 5 columns, such as arrangement X11, X12, ···, X15, ···, X61, X62, ···, X65, with the longitudinal direction along the X-axis direction. Also, the meta-atoms 101 are arranged in 5 rows and 6 columns, such as arrangement Y11, Y21, ···, Y51, ···, Y16, Y26, ···, Y56, with the longitudinal direction along the Y-axis direction. Note that the cell has a size of the grid pitch and depth greater than the outer shape of the C-shaped ring member (e.g., ring member 111B) of the meta-atom 101.

[0057] Furthermore, a through hole 20h is located in the cell positioned at the center of the metamaterial 100. When controlling the density of the plasma, the meta-atom 101D constituting the cell in the peripheral part and the meta-atom 101E near the cell of the through hole 20h may have different resonance frequencies fr. For example, the meta-atom 101D has a resonance frequency fr (= about 2.35 GHz). Also, for example, the meta-atom 101E has a resonance frequency fr (= about 2.25 GHz or about 2.55 GHz) that is separated from the resonance frequency fr of the meta-atom 101D by a predetermined frequency (e.g., ±0.2 GHz).

[0058] FIG. 10 is a perspective view showing an example of the resonator array structure according to the present embodiment. In the description of FIG. 10, the metamaterial 100 is represented in an upside-down state. Also, in FIG. 10, a ring member is drawn on some of the meta-atoms 101 so that the orientation of the meta-atoms 101 is easy to understand, but in reality, the surface is assumed to be covered with a dielectric (insulating film).

[0059] The metamaterial 100 shown in FIG. 10 has a base plate 120. The base plate 120 is made of a dielectric material such as quartz or ceramics. A plurality of grooves 121X in the X-axis direction and grooves 121Y in the Y-axis direction are provided on the base plate 120 as grooves for fitting the meta-atoms 101.

[0060] Meta-atoms 101 are respectively fitted into the grooves 121X and 121Y. In the following description, the meta-atom 101 fitted into the groove 121X may be represented as the meta-atom 101X, and the meta-atom 101 fitted into the groove 121Y may be represented as the meta-atom 101Y. Also, the meta-atom 101X is assumed to be wider than the meta-atom 101Y, and the ends of the meta-atoms 101X are in contact with each other. The regions surrounded by the meta-atom 101X and the meta-atom 101Y are cells respectively. In the example of FIG. 10, cells of 5 rows and 5 columns of cells C11 to C55 are formed.

[0061] The side pressing member 123 is fixed to the base plate 120 using screws 124 so as to contact one side of the meta-atoms 101Y at the arrangements Y11 to Y51 and the arrangements Y16 to Y56 among the outermost meta-atoms 101 shown in FIG. 2. Note that the side pressing member 123 and the screw 124 are examples of pressing members and are formed of ceramics such as alumina which is a dielectric member.

[0062] The side pressing member 127 is fixed to the base plate 120 using screws 128 so as to contact one side of the meta-atoms 101X at the arrangements X11 to X15 and the arrangements X61 to X65 among the outermost meta-atoms 101. A space 127a is formed between the side pressing member 127 and the outermost meta-atom 101X. The space 127a is provided in consideration of plasma generation. Note that the side pressing member 127 and the screw 128 are examples of pressing members and are formed of ceramics such as alumina which is a dielectric member.

[0063] The pressing member 129 presses the meta-atoms 101X and 101Y between the two side pressing members 127. The pressing member 129 is installed between the two side pressing members 127 so as to continuously press the upper part of the meta-atom 101Y in the longitudinal direction and also press the upper end part of the meta-atom 101X. That is, the pressing member 129 is installed parallel to the side pressing member 123. Note that the pressing member 129 is formed of ceramics such as alumina which is a dielectric member.

[0064] The member 130 is arranged above the side pressing member 127 to fix the pressing member 129. The end part of the pressing member 129 is sandwiched between the side pressing member 127 and the member 130. The member 130 is fixed to the side pressing member 127 by a screw 131. Note that the member 130 and the screw 131 are examples of the pressing member and are formed of ceramics such as alumina which is a dielectric member.

[0065] Next, with reference to FIGS. from FIG. 11 to FIG. 14, the arrangement and wiring of the resonators (meta-atoms) 101C in the cells C11 to C55 will be described. FIG. 11 is a plan view showing an example of the arrangement of cells when the resonator array structure according to the present embodiment is viewed from below. As shown in FIG. 11, the cells C11 to C25 and the cells C41 to C55 are surrounded by meta-atoms (resonators) 101B on all four sides. In the cells C31 to C35, meta-atoms (resonators) 101C are arranged in the Y-axis direction and meta-atoms 101B are arranged in the X-axis direction. That is, meta-atoms 101Ca to 101Cf are respectively arranged at the positions Y31 to Y36 in FIG. 2. Note that the meta-atoms 101B and 101C shown in FIG. 11 may be either of the meta-atoms 101D and 101E in FIG. 2 from the viewpoint of the resonance frequency. Also, the meta-atom 101C may be arranged in the cell C33 and any cell through which either one of the circumferences C1 and C2 passes. For example, the cells in which the meta-atom 101C is arranged include arrangements such as a combination of the cell C31 and the cell C33, and a combination of the cell C32 and the cell C33. Note that the cells C11 to C55 define the cell spaces CS11 to CS55 which are the plasma generation spaces.

[0066] FIG. 12 is a perspective view showing an example of the base plate according to the present embodiment. FIG. 13 is a cross-sectional view showing an example of the B-B cross section of FIG. 11. As shown in FIGS. 12 and 13, in the B-B cross section, each conductor 122a is provided at the bottom of each groove 121Y in which the meta-atoms 101Ca to 101Cf are arranged. Each conductor 122a is connected to each wiring 122, respectively. Each wiring 122 is connected to the measurement unit 220 via each connection part 122b and each wiring 222, respectively.

[0067] FIG. 14 is a cross-sectional view showing an example of the A-A cross section of FIG. 10. In FIG. 14, the configurations other than the base plate 120 and the meta-atoms 101Ca to 101Cf are omitted. Further, FIG. 14 is shown with the top and bottom reversed with respect to FIG. 1. FIG. 14 shows a state in which plasmas P31 to P35 are generated in the cell spaces CS31 to CS35 of the cells C31 to C35 in the A-A cross section. At this time, in the meta-atom 101Ca, the information of the plasma P31 is measured by one C-shaped ring member 111C. That is, in the meta-atom 101Ca, an alternating voltage is applied from the measurement unit 220 via the wiring 222, the connection part 122b, the wiring 122, the conductor 122a, and the wiring 114C, and the current value flowing through one C-shaped ring member 111C is measured. Note that the other C-shaped ring member 111C measures the space outside the cell C31.

[0068] In the meta-atom 101Cb, the information of the plasma P31 is measured by one C-shaped ring member 111C, and the information of the plasma P32 is measured by the other C-shaped ring member 111C. Similarly, in the meta-atoms 101Cc to 101Ce, the information of the plasmas P32 to P34 is measured by one C-shaped ring member 111C, and the information of the plasmas P33 to P35 is measured by the other C-shaped ring member 111C. Further, in the meta-atom 101Cf, similar to the meta-atom 101Ca, the information of the plasma P35 is measured by one C-shaped ring member 111C. Note that in the other C-shaped ring member 111C of the meta-atom 101Cf, the space outside the cell C35 is measured.

[0069] [Measurement with Probe] Here, with reference to FIGS. 15 and 16, the combination of the probe and the plasma in the cell space will be described. FIGS. 15 and 16 are diagrams showing an example of the combination of the probe and the plasma in the cell space. FIG. 15 shows the case where the wiring 114C of the meta-atoms 101Ca to 101Cf is independently connected to the measurement unit 220. In this case, for example, the information of the plasma P31 is obtained from the wiring 122C connected to the ring member 111C on the plasma P31 side of the meta-atom 101Ca and the wiring 122C connected to the ring member 111C on the plasma P31 side of the meta-atom 101Cb. Since these two probes (ring members 111C) measure the same plasma P31, the information of the plasma P31 can be obtained based on the average value of each current value. The information of the plasmas P32 to P35 is also obtained in the same manner based on the average value of each current value. Note that the information of the plasmas P31 to P35 includes the electron temperature Te and the electron density ne.

[0070] FIG. 16 shows the case where two wirings 114C of the meta-atoms 101Cb to 101Ce are connected by a conductor 122a to simplify the wiring and are connected to the measurement unit 220 as each wiring 122. That is, it is the case of using each wiring 122 described in FIGS. 12 to 14. In this case, if the information of the plasmas P31 to P35 is set as unknowns x1 to x5 and the current values of the probes (ring members 111C) of the meta-atoms 101Ca to 101Cf are set as current values Ia to If, it can be represented by a system of simultaneous equations of the following equations (2) to (7).

[0071] x1 = Ia ···(2) (x1 + x2) / 2 = Ib ···(3) (x2 + x3) / 2 = Ic ···(4) (x3 + x4) / 2 = Id ···(5) (x4 + x5) / 2 = Ie ···(6) x5 = If ···(7)

[0072] At this time, for example, in the probe of the meta-atom 101Cb, the current value is measured as the total value of the unknowns x1 and x2 of the plasmas P31 and P32 of the adjacent cells C31 and C32. Therefore, as shown in Equation (3), the current value Ib is the average value of the unknowns x1 and x2. Since the same applies to the meta-atoms 101Cc to 101Ce, the current values Ic to Ie are the average values of the adjacent cells as shown in Equations (4) to (6), respectively.

[0073] That is, the probe also serves as the C-shaped ring member 111C provided on both sides of one resonator (meta-atom) 101 and corresponds to the adjacent cells respectively. Also, the current value is measured as the total value of each adjacent cell. Further, the electron temperature Te and the electron density ne, which are information on the plasma, are calculated based on the average values calculated from the total values measured by each probe in the plurality of resonators 101 facing each cell.

[0074] Here, consider the number of equations and the number of unknowns. First, when the number of equations is the same as the number of unknowns, the system of simultaneous equations can be solved. When the number of equations is more than the number of unknowns (overdetermined system), the system of simultaneous equations cannot be solved, so the least squares method is used to find the solution that best satisfies all the equations. When the number of equations is less than the number of unknowns (underdetermined system), the solution of the system of simultaneous equations is not unique, so among the possible solutions, the one with the smallest distance from the origin is estimated as the solution.

[0075] (When the number of equations = the number of unknowns) For example, when not using the current value If of the meta-atom 101Cf in FIG. 16, Equations (2) to (6) can be used, and the number of equations is the same as the number of unknowns. When the system of simultaneous equations of Equations (2) to (6) is represented as Ax = b using the square matrix A as a matrix, the following Equation (8) is obtained and can be transformed into Equation (9). Also, A-1 at this time is the following Equation (10). Note that in Equation (8), the current values Ia to Ie are represented by a to e. That is, since the unknowns x1 to x5 can be calculated from Equations (8) to (10), the information on the plasmas P31 to P35 can be obtained.

[0076]

Number

Number

[0077] (When the number of equations > the number of unknowns (underdetermined system)) For example, when using all the current values Ia to If of the meta-atoms 101Ca to 101Cf in FIG. 16, since Equations (2) to (7) are used, the number of equations becomes larger than the number of unknowns. When the system of simultaneous equations of Equations (2) to (7) is represented as Ax = b using the square matrix A as a matrix, the following Equation (11) is obtained and can be transformed into Equation (12). Also, (ATA)-1AT at this time is called the Moore-Penrose inverse matrix, the generalized inverse matrix, the pseudo-inverse matrix, etc., and is the following Equation (13). Note that in Equation (11), the current values Ia to If are represented by a to f. Also, AT in Equation (12) is the transpose matrix of A. That is, since the unknowns x1 to x5 can be calculated from Equations (11) to (13), the information on the plasmas P31 to P35 can be obtained. Note that obtaining Equation (12) is mathematically equivalent to estimating the solution by the least squares method.

[0078]

Math

Math

[0079] (When the number of equations < the number of unknowns (underdetermined system)) For example, when using the current values Ib to Ie of the meta-atoms 101Cb to 101Ce in FIG. 16, since equations (3) to (6) are used, the number of equations becomes less than the number of unknowns. When representing the system of simultaneous equations (3) to (6) as a matrix equation Ax = b using a square matrix A, the following equation (14) is obtained and can be transformed into equation (15). Also, AT(AAT)-1 at this time is called the Moore-Penrose inverse matrix, the generalized inverse matrix, the pseudo-inverse matrix, etc., and becomes the following equation (16). Note that in equation (14), the current values Ib to Ie are represented by b to e. Also, AT in equation (15) is the transpose matrix of A. That is, since the unknowns x1 to x5 can be calculated from equations (14) to (16), the information of the plasmas P31 to P35 can be obtained. Note that obtaining equation (15) is mathematically equivalent to obtaining the solution with the minimum distance from the origin among the possible solutions. Also, even when the number of equations is even fewer, the plasma information can be obtained in the same way. That is, the arrangement of the meta-atom 101, which is the measurement location of the plasma, is not restricted by the arrangement of each meta-atom 101 in the resonator array structure 100 and can be an arbitrary position.

[0080]

Math

[0081] [Calculation of Electron Temperature Te and Electron Density ne] Next, the calculation of the electron temperature Te and the electron density ne based on the current value measured by the probe will be described. FIG. 17 is a diagram showing an example of an equivalent circuit for plasma measurement using an insulating probe. As shown in FIG. 17, in the present embodiment, an AC voltage V0=Acosωt is applied to the plasma via a resistor R and a capacitor C. In the insulating probe of the present embodiment, similar to the Langmuir probe, the non-linearity of the current I with respect to the plasma voltage Vp is utilized. Further, since the AC voltage V0 is applied via the capacitor C, plasma measurement can be performed even during a process in which a by-product (depo) that would block the DC current is generated. The AC voltage V0 is measured by the power supply unit of the measurement unit 220 that applies the AC voltage V0, and the current I is measured by an ammeter connected in series with the resistor R of the measurement unit 220. Here, the current I is represented by the following equation (17). Also, the non-linearity of the current I with respect to the plasma voltage Vp is represented by equation (18) assuming a Maxwell distribution. Note that equation (18) is the same equation as that of the Langmuir probe. Also, the ion saturation current Iis is represented by the following equation (19), and the electron saturation current Ies is represented by the following equation (20).

[0082] I=f(Vp) ···(17) [Number]

Number

Number

[0083] Here, \(V_f\) represents the floating potential, \(\varphi_p\) represents the plasma potential, \(T_e\) represents the electron temperature in eV units, \(n_e\) represents the electron density, \(S\) represents the probe area, \(e\) represents the elementary charge, \(M_i\) represents the mass of ions, and \(m_e\) represents the mass of electrons. The AC voltage amplitude \(V_0\) and Equation (17) are applied to Equation (18), and the current is decomposed into frequency components as shown in Equation (22) using the first-kind modified Bessel function as shown in the following Equation (21).

[0084]

Number

Number

[0085] Since the information on the electron density is only included in the coefficient (electron saturation current \(I_{es}\)) of each frequency component, as shown in the following Equation (23), by dividing the fundamental current by the second harmonic current, the electron density \(n_e\) can be eliminated from the equation, and then the electron temperature \(T_e\) is calculated.

[0086]

Number

[0087] The left side of Equation (23) is the measured value and represents the ratio of the amplitude of the fundamental wave (1ω) current \(i_{1\omega}\) to the amplitude of the first harmonic wave (2ω) current \(i_{2\omega}\). Also, the right side of Equation (23) represents the ratio of the fundamental wave (fundamental current) to the first harmonic wave (second harmonic current) when the current value measured by the insulation probe is expanded using the first-kind modified Bessel function. Therefore, the electron temperature \(T_e\) can be calculated based on Equation (23) from the ratio of the measured values and the ratio of the fundamental wave to the first harmonic wave calculated by Fourier series expansion.

[0088] Also, the AC component of the current \(i_{1\omega}\) is represented by the following Equation (24).

[0089]

Number

[0090] Based on the calculated electron temperature \(T_e\) and the fundamental wave (1ω) current \(i_{1\omega}\), the electron density \(n_e\) can be calculated by the following Equation (25).

[0091]

Number

[0092] FIG. 18 is a diagram showing an example of the Fourier series expansion result of the measured current value. The graph 300 shown in FIG. 18 shows the Fourier series expansion result of the current value measured by the insulation probe. In the probe in contact with the plasma, current flows exponentially with respect to the applied voltage of the probe. The measured current value when an alternating voltage is applied includes, for example, a fundamental wave (1ω) component having a fundamental frequency, and harmonic components such as a first harmonic (2ω) having a wavelength twice that of the fundamental wave and a second harmonic (3ω) having a wavelength three times that of the fundamental wave. In the example of the graph 300, a peak around 31 kHz as the fundamental wave (1ω), a peak around 62 kHz as the first harmonic (2ω), and a peak around 93 kHz as the second harmonic (3ω) are included. By performing Fourier series expansion on the measured current value, as shown in the above formula (23), the ratio between the fundamental wave (1ω) and the first harmonic (2ω) can be obtained.

[0093] That is, in the present embodiment, by applying a sine-wave alternating voltage to the insulation probe (ring member 111C), detecting the waveform distorted by the plasma, and performing Fourier series expansion, the electron temperature Te and the electron density ne can be calculated. For example, in the example of FIG. 16, the measured current values Ia to If measured by the probes (ring members 111C) of the meta-atoms 101Ca to 101Cf are subjected to Fourier series expansion, and the electron temperature Te and the electron density ne are calculated as unknowns x1 to x5, respectively.

[0094] [Plasma Measurement Method] Next, an example of the plasma measurement process in the plasma processing apparatus 1 will be described. FIG. 19 is a flowchart showing an example of the plasma measurement process according to the present embodiment. The plasma measurement process shown in FIG. 19 is realized by controlling each part of the apparatus main body 10 by the control device 11.

[0095] First, the workpiece WP is carried into the processing chamber 12 and placed on the electrostatic chuck 14c. Then, the control device 11 opens the valve 38b and controls the flow controller 38c so that a processing gas with a predetermined flow rate is supplied into the processing chamber 12. And the control device 11 controls the exhaust device 56 to adjust the pressure inside the processing chamber 12. Next, the control device 11 controls the microwave output device 16 to supply microwaves from the coaxial waveguide 28 to the processing space S inside the processing chamber 12. Thereby, plasma of the processing gas is generated inside the processing chamber 12 (step S1). Here, a plasma processing process for the workpiece WP is executed by the plasma generated in the processing space S inside the processing chamber 12.

[0096] The control device 11 controls the measurement unit 220 to apply an alternating voltage to the C-shaped ring member 111C of the meta-atom 101C that also serves as a probe (step S2). The control device 11 controls the measurement unit 220 to measure the current value flowing through the probe (ring member 111C) (step S3). The control device 11 controls the measurement unit 220 to calculate the electron temperature Te and the electron density ne based on the measured current value (step S4). The control device 11 acquires the electron temperature Te and the electron density ne from the measurement unit 220. The control device 11 controls the plasma, for example, by controlling the microwave output device 16 to adjust the frequency of the electromagnetic wave, etc., based on the acquired electron temperature Te and electron density ne.

[0097] When the plasma processing process ends, the processed workpiece WP is carried out of the processing chamber 12 by a robot arm not shown in the figure.

[0098] As described above, according to the present embodiment, the plasma processing apparatus 1 includes a processing container 12, an electromagnetic wave generator (microwave output device 16), a first dielectric (dielectric window 20), an electromagnetic wave supply unit (antenna 18), and a resonator array structure 100. The processing container 12 provides a processing space S. The electromagnetic wave generator is configured to supply electromagnetic waves and generate plasma in the processing space. The first dielectric is provided with its first surface facing the processing space S. The electromagnetic wave supply unit is configured to supply electromagnetic waves to the processing space S through the first dielectric. The resonator array structure 100 is located in the processing container 12 along the first surface of the first dielectric. Further, the resonator array structure 100 includes a plurality of resonators 101 that can resonate with the magnetic field component of the electromagnetic wave and have a size smaller than the wavelength of the electromagnetic wave. The plurality of resonators have a structure in which C-shaped ring members (ring members 111A to 111C) made of a conductor are laminated on one surface of dielectric plates (dielectric plates 112A to 112C). At least one of the C-shaped ring members (ring member 111C) also serves as a probe for measuring plasma information. As a result, it is possible to achieve high density of plasma over a wide range, and the plasma generated through the resonator array structure 100 can be quantitatively evaluated in its vicinity.

[0099] Further, according to the present embodiment, the plasma processing apparatus 1 further includes a power supply unit (measurement unit 220) that applies an alternating voltage to the probe (ring member 111C) through wirings (wirings 222, 122, 114C), and an ammeter (measurement unit 220) that measures the current value flowing through the probe. As a result, even for plasma in plasma processing where by-products (deposits) are generated, it can be quantitatively evaluated in its vicinity.

[0100] Further, according to the present embodiment, the frequency of the alternating voltage is lower than the frequency of the electromagnetic wave supplied from the electromagnetic wave generator to the processing space S. As a result, it is possible to prevent the alternating voltage for measurement from affecting plasma generation in the resonator array structure 100.

[0101] Also, according to the present embodiment, the frequency of the alternating voltage is a frequency of 100 kHz or less. As a result, it is possible to prevent the alternating voltage for measurement from affecting plasma generation in the resonator array structure 100.

[0102] Also, according to the present embodiment, the resonator array structure 100 further includes a base plate 120 having grooves (grooves 121X and 121Y) on the surface on the processing space S side, and pressing members (side pressing members 123 and 127, pressing member 129) configured to press a plurality of resonators 101 fitted in a direction perpendicular to the grooves toward the base plate 120 side. The wiring 122 is provided in the grooves and connected to the probes. As a result, a plurality of cells (for example, cells C11 to C55) can be formed, and the probes (ring members 111C) can be arranged so that the plasma of a specific cell (for example, cells C31 to C35) can be measured.

[0103] Also, according to the present embodiment, the C-shaped ring members are formed on both surfaces of the dielectric plate. As a result, each resonator 101 can form a series resonance circuit.

[0104] Also, according to the present embodiment, the C-shaped ring members are covered with a second dielectric (films 113 and 113C). As a result, abnormal discharge in each resonator 101 can be suppressed.

[0105] Also, according to the present embodiment, the C-shaped ring member 111C is formed on both surfaces of the dielectric plate 112C and covered with a second dielectric (film 113C). Also, the thickness of the dielectric plate 112C between the C-shaped ring members 111C formed on both surfaces of the dielectric plate 112C is thicker than the thickness of the second dielectric covering the C-shaped ring member 111C. As a result, the C-shaped ring member 111C can function as an insulating probe for measuring the plasma on the film 113C side.

[0106] Also, according to the present embodiment, the thickness of the dielectric plate 112C is 100 times or more the thickness of the second dielectric. As a result, the C-shaped ring member 111C can function as an insulating probe for measuring the plasma on the coating 113C side.

[0107] Also, according to the present embodiment, the groove is provided so that a plurality of cells surrounded by a plurality of resonators 101 fitted into the groove can be formed. Among the plurality of cells (for example, cells C11 to C55), at least one resonator 101C including a C-shaped ring member 111C that also serves as a probe is provided in at least two cells (for example, cells C31 and C33). As a result, based on the plasma information measured in the two cells, the plasma information of other cells can be estimated.

[0108] Also, according to the present embodiment, the probe is provided in a first cell (for example, cell C31) at the center of the resonator array structure 100 and at least one second cell (for example, cell C33) located on the outer peripheral side of the first cell among the plurality of cells. As a result, based on the plasma information measured in the first cell and the second cell, the plasma information of other cells can be estimated.

[0109] Also, according to the present embodiment, the probe is provided in a first cell (for example, cell C31) and at least one second cell (for example, cell C33) located on a straight line in the horizontal direction with respect to the base plate 120 passing through the first cell (for example, line A-A in FIG. 10) among the plurality of cells. As a result, based on the plasma information measured in the first cell and the second cell, the plasma information of other cells located on the straight line can be estimated. Furthermore, based on the plasma information of the plurality of cells located on the straight line, the plasma information of the plurality of cells at other positions can be estimated.

[0110] Also, according to the present embodiment, the second cell is adjacent to the first cell or another second cell. As a result, based on the plasma information measured in the first cell and the second cell, the plasma information of other cells located on the straight line connecting the first cell and the second cell can be easily estimated.

[0111] Also, according to the present embodiment, the C-shaped ring member 111C formed on both surfaces of the dielectric plate 112C also serves as a probe and is connected to the conductor 122a provided at the bottom of the groove and is in a conductive state with each other, and the wiring 122 is connected to the conductor 122a. As a result, the wiring 122 can be simplified.

[0112] Also, according to the present embodiment, the plasma measurement method is a plasma measurement method in the plasma processing apparatus 1, in which electromagnetic waves are supplied into the processing vessel 12, and a plurality of resonators 101 included in the resonator array structure 100 located in the processing vessel 12, which are capable of resonating with the magnetic field component of the electromagnetic waves and have a size smaller than the wavelength of the electromagnetic waves, are formed in a plurality of cells (for example, C11 to C55). In a state where plasma is generated in the plurality of cells, an AC voltage is applied to a probe that measures the plasma information served by at least one (ring member 111C) of the C-shaped ring members (ring members 111A to 111C) made of conductors included in the plurality of resonators 101, the current value flowing through the probe is measured, and based on the measured current value, the electron temperature and electron density of the plasma in the cell where the probe is arranged are calculated. The plasma processing apparatus executes the above operations. As a result, the plasma generated through the resonator array structure 100 can be quantitatively evaluated in the vicinity thereof.

[0113] Also, according to the present embodiment, the probes are provided in a plurality of cells, and the current values are measured for each cell. As a result, the plasma information for each cell can be calculated.

[0114] Further, according to the present embodiment, the probe also serves as a C-shaped ring member 111C provided on both surfaces of one resonator 101, corresponding to adjacent cells respectively. The current value is measured as the total value of each adjacent cell, and the electron temperature and electron density of the plasma are calculated based on the average value calculated from the total value measured by each probe in a plurality of resonators 101 facing each cell. As a result, while simplifying the wiring 122, it is possible to calculate the plasma information of each adjacent cell.

[0115] Further, according to the present embodiment, the number of probes is the same as the number of cells, and the electron temperature and electron density of the plasma are calculated using the same number of simultaneous equations as the number of probes. As a result, it is possible to calculate the plasma information of the cells more accurately.

[0116] Further, according to the present embodiment, the number of probes is more than the number of cells, and the electron temperature and electron density of the plasma are calculated using the same number of simultaneous equations as the number of probes. As a result, it is possible to calculate the plasma information of the cells as an overdetermined system.

[0117] Further, according to the present embodiment, the number of probes is less than the number of cells, and the electron temperature and electron density of the plasma are calculated using the same number of simultaneous equations as the number of probes. As a result, it is possible to calculate the plasma information of the cells as an underdetermined system.

[0118] The embodiments disclosed this time should be considered as illustrative in all respects and not restrictive. The above embodiments may be omitted, replaced, or changed in various forms without departing from the scope and gist of the appended claims.

[0119] Also, in the above-described embodiment, the resonator array structure 100 in which a plurality of resonators 101 are arranged in a lattice shape has been described, but it is not limited thereto. For example, a resonator array structure may be formed by combining a plurality of strip-shaped resonators in which a plurality of resonators 101 in the X-axis direction or the Y-axis direction are integrated.

[0120] In the above-described embodiment, the resonator array structure 100 is arranged along the lower surface 20a of the dielectric window 20, but the present invention is not limited thereto. For example, the resonator array structure 100 may be embedded in the dielectric window 20 or may be arranged at a distance from the lower surface 20a of the dielectric window 20. Further, for example, the resonator array structure 100 may be arranged along the upper surface of the electrostatic chuck 14c provided with the upper surface facing the processing space S, or may be arranged at a distance from the upper surface of the electrostatic chuck 14c. Also, for example, the resonator array structure 100 may be arranged along the inner wall surface of the side wall 12a of the processing container 12, or may be arranged at a distance from the inner wall surface of the side wall 12a of the processing container 12.

[0121] In the above-described embodiment, the output portion of the microwave output device 16 may be connected to the base 14a which is a high-frequency electrode. In this case, the base 14a supplies the electromagnetic wave output from the microwave output device 16 to the processing space S through the electrostatic chuck 14c. Also, in such a configuration, the resonator array structure 100 may be embedded in the electrostatic chuck 14c.

[0122] In the above-described embodiment, the case where the resonator array structure 100 is formed by arranging a plurality of resonators 101 that can resonate with the magnetic field component of the electromagnetic wave and have a size smaller than the wavelength of the electromagnetic wave in a lattice pattern in the direction along the lower surface 20a of the dielectric window 20 has been described as an example. However, the present invention is not limited thereto, and the arrangement of the plurality of resonators 101 may be any arrangement in the direction along the lower surface 20a of the dielectric window 20. For example, the plurality of resonators 101 may be arranged at a predetermined interval along one direction. Also, for example, the resonator array structure may be configured in a flat plate shape, and the plurality of resonators 101 may be arranged in a lattice pattern in the direction of a plane parallel to the lower surface 20a of the dielectric window 20. That is, when viewed from the lower surface 20a side, the C-shaped ring members that are represented by being transmitted may be arranged in a lattice pattern so that the C shape can be seen. In this case, the magnetic field generated by the antenna is in the direction penetrating the C-shaped ring member.

[0123] Furthermore, although an inductively coupled coil was used as the antenna for inputting electromagnetic waves in the above-described embodiment, the invention is not limited to this, as long as a magnetic field can be generated in a direction that penetrates the ring members 111A to 111C of the multiple resonators 101 of the resonator array structure 100. The antenna for inputting such electromagnetic waves is not limited to an inductively coupled coil, and any antenna or mechanism for inputting electromagnetic waves can be used, such as a slot antenna, monopole antenna, capacitively coupled electrode, or magnetron.

[0124] Furthermore, although microwaves were used as the electromagnetic waves supplied to the processing space S for plasma excitation in the embodiments described above, the invention is not limited to microwaves. For example, electromagnetic waves in the very high frequency (VHF) to ultra high frequency (UHF) band may be supplied to the processing space S as the electromagnetic waves for plasma excitation.

[0125] Furthermore, this disclosure can also be structured as follows: (1) A processing container that provides a processing space, An electromagnetic wave generator configured to supply electromagnetic waves and generate plasma in the processing space, A first dielectric is provided with its first surface facing the processing space, An electromagnetic wave supply unit configured to supply the electromagnetic waves to the processing space via the first dielectric, A resonator array structure positioned along the first surface of the first dielectric within the processing container, Equipped with, The aforementioned resonator array structure is It includes a plurality of resonators that are capable of resonating with the magnetic field component of the electromagnetic wave and whose size is smaller than the wavelength of the electromagnetic wave, The plurality of resonators have a structure in which C-shaped ring members made of conductors are stacked on one surface of a dielectric plate. At least one of the C-shaped ring members also serves as a probe for measuring the plasma information. Plasma processing equipment. (2) A power supply unit that applies an alternating voltage to the probe via a wiring, An ammeter that measures the current value flowing through the probe, further comprising. The plasma processing apparatus according to (1) above. (3) The frequency of the alternating voltage is lower than the frequency of the electromagnetic wave supplied from the electromagnetic wave generator to the processing space. The plasma processing apparatus according to (2) above. (4) The frequency of the alternating voltage is a frequency of 100 kHz or less. The plasma processing apparatus according to (3) above. (5) The resonator array structure, A base plate having grooves on the surface on the processing space side, A pressing member configured to press the plurality of resonators fitted in the vertical direction of the grooves toward the base plate side, further including. The wiring is provided in the grooves and connected to the probe. The plasma processing apparatus according to (2) or (3) above. (6) The C-shaped ring member is formed on both surfaces of the dielectric plate. The plasma processing apparatus according to any one of (1) to (5) above. (7) The C-shaped ring member is covered with a second dielectric. The plasma processing apparatus according to any one of (1) to (6) above. (8) The C-shaped ring member is formed on both surfaces of the dielectric plate and covered with a second dielectric. The thickness of the dielectric plate between the C-shaped ring members formed on both surfaces of the dielectric plate is thicker than the thickness of the second dielectric covering the C-shaped ring member. The plasma processing apparatus according to (6) above. (9) The thickness of the dielectric plate is 100 times or more the thickness of the second dielectric. The plasma processing apparatus according to (8) above. (10) The groove is provided so that a plurality of cells surrounded by the plurality of resonators fitted in the groove can be formed. Among the plurality of cells, at least one resonator including the C-shaped ring member also serving as the probe is provided in at least two cells respectively. The plasma processing apparatus according to (5) above. (11) The probe is provided in the first cell at the center of the resonator array structure and at least one second cell located on the outer peripheral side of the first cell among the plurality of cells. The plasma processing apparatus according to (10) above. (12) The probe is provided in the first cell and at least one second cell located on a straight line in the horizontal direction with respect to the base plate passing through the first cell among the plurality of cells. The plasma processing apparatus according to (11) above. (13) The second cell is adjacent to the first cell or another second cell. The plasma processing apparatus according to (12) above. (14) The C-shaped ring members formed on both surfaces of the dielectric plate also serve as the probe and are connected to the conductor provided at the bottom of the groove and are in a conductive state with each other. The wiring is connected to the conductor. The plasma processing apparatus according to (5) above. (15) A plasma measurement method in a plasma processing apparatus, An alternating voltage is applied to a probe that measures information on the plasma, where at least one of C-shaped ring members made of a conductor included in a plurality of resonators resonates with a magnetic field component of electromagnetic waves and has a size smaller than the wavelength of the electromagnetic waves, in a state where the electromagnetic waves are supplied into a processing vessel of the plasma processing apparatus and plasma is generated in a plurality of cells formed by the plurality of resonators located in the processing vessel. Measuring a current value flowing through the probe. Based on the measured current value, calculating an electron temperature and an electron density of the plasma in the cell where the probe is disposed. A plasma measurement method executed by a plasma processing apparatus. (16) The probe is provided in a plurality of the cells. The current value is measured for each of the cells. The plasma measurement method according to (15) above. (17) The probe is also served by the C-shaped ring members provided on both surfaces of one of the resonators, corresponding to adjacent cells respectively. The current value is measured as a total value of each of the adjacent cells. The electron temperature and the electron density of the plasma are calculated based on average values calculated from the total values measured by the respective probes in a plurality of the resonators facing each of the cells. The plasma measurement method according to (15) above. (18) The number of the probes and the number of the cells are the same. The electron temperature and the electron density of the plasma are calculated using a system of simultaneous equations having the same number as the number of the probes. The plasma measurement method according to (17) above. (19) The number of the probes is larger than the number of the cells. The electron temperature and the electron density of the plasma are calculated using a system of simultaneous equations having the same number as the number of the probes. The plasma measurement method according to (17) above. (20) The number of the probes is less than the number of the cells. The electron temperature and the electron density of the plasma are calculated using a system of simultaneous equations having the same number as the number of the probes. The plasma measurement method according to (17) above.

Explanation of Signs

[0126] 1 Plasma processing apparatus 10 Apparatus main body 11 Control device 12 Processing container 16 Microwave output device 18 Antenna 20 Dielectric window 100 Resonator array structure (metamaterial) 101 Resonator (meta-atom) 111A~111C Ring members 112A~112C Dielectric plates 113,113C Films 114C,122,222 Wires 120 Base plate 121X,121Y Grooves 122a Conductor 123,127 Side pressing members 129 Pressing member 220 Measuring unit C11~C55 Cells S Processing space

Claims

1. A processing container providing a processing space, An electromagnetic wave generator configured to supply electromagnetic waves and generate plasma in the processing space, A first dielectric provided with a first surface facing the processing space, An electromagnetic wave supply unit configured to supply the electromagnetic waves to the processing space through the first dielectric, A resonator array structure positioned along the first surface of the first dielectric within the processing container, Comprising, The resonator array structure, Includes a plurality of resonators capable of resonating with the magnetic field component of the electromagnetic wave and having a size smaller than the wavelength of the electromagnetic wave, The plurality of resonators have a structure in which a C-shaped ring member made of a conductor is laminated on one surface of a dielectric plate, At least one of the C-shaped ring members also serves as a probe for measuring information on the plasma, A plasma processing apparatus.

2. A power supply unit for applying an alternating voltage to the probe via a wiring, A current meter for measuring the value of the current flowing through the probe, further comprising, The plasma processing apparatus according to Claim 1.

3. The frequency of the alternating voltage is lower than the frequency of the electromagnetic wave supplied from the electromagnetic wave generator to the processing space, The plasma processing apparatus according to Claim 2.

4. The frequency of the alternating voltage is a frequency of 100 kHz or less, The plasma processing apparatus according to Claim 3.

5. The resonator array structure, A base plate having grooves on the surface facing the processing space, A pressing member configured to press the plurality of resonators fitted in the vertical direction of the grooves toward the base plate side, further comprising, The wiring is provided in the grooves and connected to the probe, The plasma processing apparatus according to Claim 2 or 3.

6. The C-shaped ring member is formed on both surfaces of the dielectric plate, The plasma processing apparatus according to Claim 1 or 2.

7. The C-shaped ring member is covered with a second dielectric, The plasma processing apparatus according to Claim 1 or 2.

8. The C-shaped ring member is formed on both surfaces of the dielectric plate and covered with a second dielectric, The thickness of the dielectric plate between the C-shaped ring members formed on both surfaces of the dielectric plate is thicker than the thickness of the second dielectric covering the C-shaped ring member, The plasma processing apparatus according to Claim 6.

9. The thickness of the dielectric plate is 100 times or more the thickness of the second dielectric, The plasma processing apparatus according to Claim 8.

10. The groove is provided so as to be able to form a plurality of cells surrounded by the plurality of resonators fitted in the groove, Among the plurality of cells, at least one resonator including the C-shaped ring member also serving as the probe is provided in at least two cells respectively, The plasma processing apparatus according to claim 5.

11. The probe is provided in a first cell at the center of the resonator array structure and at least one second cell located on the outer peripheral side of the first cell among the plurality of cells, The plasma processing apparatus according to claim 10.

12. The probe is provided in the first cell and at least one second cell located on a straight line in the horizontal direction with respect to the base plate through the first cell among the plurality of cells, The plasma processing apparatus according to claim 11.

13. The second cell is adjacent to the first cell or another second cell, The plasma processing apparatus according to claim 12.

14. The C-shaped ring members formed on both surfaces of the dielectric plate also serve as the probe and are connected to a conductor provided at the bottom of the groove and are in a conductive state with each other, The wiring is connected to the conductor, The plasma processing apparatus according to claim 5.

15. A plasma measurement method in a plasma processing apparatus, While electromagnetic waves are supplied into the processing vessel of the plasma processing apparatus and plasma is generated in a plurality of cells formed by a plurality of resonators that can resonate with the magnetic field component of the electromagnetic waves and have a size smaller than the wavelength of the electromagnetic waves included in the resonator array structure located in the processing vessel, applying an alternating voltage to a probe that measures information on the plasma served by at least one of C-shaped ring members made of a conductor included in the plurality of resonators, Measuring the current value flowing through the probe, Calculating the electron temperature and electron density of the plasma in the cell where the probe is arranged based on the measured current value, A plasma measurement method executed by the plasma processing apparatus.

16. The probe is provided in a plurality of the cells, The current value is measured for each cell, The plasma measurement method according to claim 15.

17. The probe also serves as the C-shaped ring member provided on both sides of one of the resonators, corresponding to adjacent cells respectively, The current value is measured as the total value of each of the adjacent cells, The electron temperature and the electron density of the plasma are calculated based on the average value calculated from the total value measured by each of the probes in the plurality of resonators facing each of the cells. The plasma measurement method according to claim 15.

18. The number of the probes is the same as the number of the cells, The electron temperature and the electron density of the plasma are calculated using the same number of simultaneous equations as the number of the probes. The plasma measurement method according to claim 17.

19. The number of the probes is more than the number of the cells, The electron temperature and the electron density of the plasma are calculated using the same number of simultaneous equations as the number of the probes. The plasma measurement method according to claim 17.

20. The number of the probes is less than the number of the cells, The electron temperature and the electron density of the plasma are calculated using the same number of simultaneous equations as the number of the probes. The plasma measurement method according to claim 17.

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