JP2013175480A - Plasma processing apparatus and plasma processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma processing apparatus that is capable of improving uniformity of density of plasma excited at a high frequency, such as a VHF frequency band, for a large-sized substrate.SOLUTION: A plasma processing apparatus includes: waveguide members 401 that define waveguides WG; a coaxial tube 225 that supplies electromagnetic energy into the waveguides WG from predetermined feed positions in a lengthwise direction A of the waveguides WG; and a plurality of electrodes 461 for electric field formation, to which the electromagnetic energy is supplied through the waveguides WG and which are disposed to face a plasma formation space. The plurality of electrodes 461 are arranged along the lengthwise direction A of the waveguides WG so that each of the plurality of electrodes 461 extends in a widthwise direction B of the waveguides WG.

Description

  The present invention relates to a plasma processing apparatus and a plasma processing method for performing plasma processing on a substrate.

  In the manufacturing process of a flat panel display, a solar cell, a semiconductor device, etc., plasma is used for forming a thin film or etching. The plasma is generated, for example, by introducing a gas into a vacuum chamber and applying a high frequency of several MHz to several hundred MHz to an electrode provided in the chamber. In order to improve productivity, the size of a glass substrate for a flat panel display or a solar cell is increasing year by year, and mass production is already performed on a glass substrate exceeding 2 m square.

  In a film formation process such as plasma CVD (Chemical Vapor Deposition), a plasma with a higher density is required in order to improve the film formation speed. Further, in order to reduce ion irradiation damage by suppressing the energy of ions incident on the substrate surface and to suppress excessive dissociation of gas molecules, plasma having a low electron temperature is required. In general, when the plasma excitation frequency is increased, the plasma density increases and the electron temperature decreases. Therefore, in order to form a high-quality thin film with high throughput, it is necessary to increase the plasma excitation frequency. Therefore, a high frequency of a VHF (Very High Frequency) band of 30 to 300 MHz, which is higher than a frequency of 13.56 MHz, which is a frequency of a normal high frequency power source, is used for plasma processing (for example, see Patent Documents 1 and 2).

JP-A-9-31268 JP 2009-021256 A

  By the way, when the size of the glass substrate to be processed becomes large, for example, 2 m square, when the plasma processing is performed at the plasma excitation frequency in the VHF band as described above, the surface wave generated in the electrode to which the high frequency is applied is generated. The uniformity of the plasma density is reduced by the standing wave. Generally, when the size of an electrode to which a high frequency is applied is larger than 1/20 of the wavelength in free space, uniform plasma cannot be excited unless some measures are taken.

  The present invention provides a plasma processing apparatus capable of improving the uniformity of the density of plasma excited at a high frequency such as the VHF frequency band on a substrate having a larger size than 2 m square.

  The plasma processing apparatus of the present invention includes a waveguide member that defines a waveguide, a transmission path that supplies electromagnetic energy into the waveguide from a predetermined feeding position in the longitudinal direction of the waveguide, and electromagnetic energy through the waveguide. And a plurality of electric field forming electrodes arranged to face the plasma forming space, and the plurality of electrodes are arranged along the longitudinal direction of the waveguide, Each of the electrodes extends in the width direction of the waveguide.

  ADVANTAGE OF THE INVENTION According to this invention, the uniformity of the density of the plasma excited in a VHF frequency band can be improved with respect to the to-be-processed object (board | substrate) of a larger size in the longitudinal direction and width direction of a waveguide.

It is sectional drawing which shows an example of a plasma processing apparatus. It is II-II sectional drawing of the plasma processing apparatus of FIG. It is a perspective sectional view showing a waveguide in a cut-off state. FIG. 3B is a perspective sectional view of a waveguide having an equivalent relationship to the waveguide of FIG. 3A. FIG. 2 is a perspective sectional view showing a structure of a basic type plasma generation mechanism in the plasma processing apparatus of FIG. 1. It is a perspective sectional view showing the structure of the plasma generation mechanism concerning a 1st embodiment of the present invention. FIG. 6 is a perspective cross-sectional view showing an appearance of the plasma generation mechanism of FIG. 5 as viewed from the coaxial tube side. FIG. 6 is a perspective sectional view showing an appearance of the plasma generation mechanism of FIG. It is a perspective view of an electrode unit. It is sectional drawing of an electrode unit. It is a figure for demonstrating electric field formation in an electrode unit. It is a perspective view which shows the other example of an electrode unit. It is sectional drawing of the electrode unit of FIG. It is a graph which shows an example of electric field strength distribution in the width direction of a waveguide in a basic type plasma generation mechanism.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

[Basic configuration of plasma processing equipment]
First, an example of a plasma processing apparatus of the type to which the present invention is applied will be described with reference to FIGS. 1 is a cross-sectional view taken along the line II in FIG. 2, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG. The plasma processing apparatus 10 shown in FIGS. 1 and 2 supplies electromagnetic energy to an electrode using a waveguide designed so that the supplied electromagnetic wave resonates, thereby along the longitudinal direction of the waveguide. It has a configuration capable of exciting a uniform density plasma.

  Here, the resonance of the waveguide will be described. First, as shown in FIG. 3A, the in-tube wavelength of a rectangular waveguide GT having a cross section with a long side length a and a short side length b will be considered. The guide wavelength λg is expressed by the equation (1).

  Here, λ is the wavelength in free space, εr is the relative permittivity in the waveguide, and μr is the relative permeability in the waveguide. According to equation (1), it is understood that the in-tube wavelength λg of the waveguide GT is always longer than the wavelength λ in free space when εr = μr = 1. When λ <2a, the guide wavelength λg increases as the long side length a decreases. When λ = 2a, that is, when the length a of the long side is equal to ½ of the wavelength λ in free space, the denominator becomes 0 and the in-tube wavelength λg becomes infinite. At this time, the waveguide GT is cut off, the phase velocity of the electromagnetic wave propagating in the waveguide GT is infinite, and the group velocity is zero. Furthermore, when λ> 2a, the electromagnetic wave cannot propagate through the waveguide, but can enter a certain distance. In general, this state is also referred to as a cut-off state. Here, the state when λ = 2a is referred to as a cut-off state. For example, at a plasma excitation frequency of 60 MHz, a is 250 cm in the hollow waveguide, and a is 81 cm in the alumina waveguide.

  FIG. 3B shows a basic type of waveguide used in the plasma processing apparatus 10. The waveguide member GM that defines the waveguide WG is formed of a conductive member, and the side wall portions W1 and W2 facing each other in the waveguide direction (longitudinal direction) A and the width direction B and the heights of the side wall portions W1 and W2 are set. The lower end in the length direction H has first and second electrode portions EL1, EL2 extending in a flange shape. A plate-like dielectric DI is inserted in the gap formed between the side wall portions W1 and W2. The dielectric DI plays a role of preventing the plasma from being excited in the waveguide WG. The width w of the waveguide WG shown in FIG. 3B is set to a value equal to the length b of the short side of the waveguide, and the height h is electrically equivalent to the waveguide GT in the cutoff state. It is set to an optimum value smaller than λ / 4 (a / 2). In the waveguide WG, an LC resonance circuit including L (inductance) and C (capacitance) is formed, and the supplied electromagnetic wave resonates by being cut off. If the high-frequency wavelength propagating in the waveguide direction WG in the waveguide WG is made infinite, a uniform high-frequency electric field is formed along the longitudinal direction of the electrodes EL1 and EL2, and plasma having a uniform density in the longitudinal direction is excited. Is done. If the impedance when the plasma side is viewed from the waveguide WG is infinite, the waveguide WG can be regarded as a transmission line obtained by dividing the rectangular waveguide into two equal parts in the long side direction. Therefore, when the height h of the waveguide WG is λ / 4, the guide wavelength λg becomes infinite. However, since the impedance when the plasma side is viewed from the waveguide WG is actually capacitive, the height h of the waveguide WG that makes the in-tube wavelength λg infinite is smaller than λ / 4.

  The plasma processing apparatus 10 includes a vacuum container 100 on which a substrate G is placed, and plasma-processes a glass substrate (hereinafter referred to as a substrate G) inside. The vacuum vessel 100 has a rectangular cross section, is formed of a metal such as an aluminum alloy, and is grounded. The upper opening of the vacuum vessel 100 is covered with a ceiling portion 105. The substrate G is mounted on the mounting table 115. The substrate G is an example of an object to be processed, and is not limited to this, and may be a silicon wafer or the like.

  On the floor of the vacuum vessel 100, a mounting table 115 is provided for placing the substrate G. Above the mounting table 115, a plurality (two) of plasma generation mechanisms 200 are provided via the plasma formation space PS. The plasma generation mechanism 200 is fixed to the ceiling portion 105 of the vacuum vessel 100.

  Each plasma generating mechanism 200 includes two waveguide members 201A and 201B of the same size formed of an aluminum alloy, a coaxial tube 225, and a waveguide WG formed between two opposing waveguide members 201A and 201B. And a dielectric plate 220 inserted therein.

  In order to form the waveguide WG, the waveguide members 201A and 201B are an electric field that excites a flat plate portion 201W facing each other with a predetermined gap and a plasma formed in a flange shape at the lower end portion of the flat plate portion 201W. Each has electrode portions 201EA and 201EB for forming. The upper end portions of the waveguide members 201A and 201B are connected to the ceiling portion 105 made of a conductive material, and the upper end portions of the waveguide members 201A and 201B are electrically connected to each other.

  The dielectric plate 220 is formed of a dielectric material such as aluminum oxide or quartz, and extends upward from the lower end of the waveguide WG to the middle of the waveguide WG. Since the upper part of the waveguide WG is short-circuited, the electric field on the upper side of the waveguide WG is weaker than that on the lower side. Therefore, if the lower side of the waveguide WG having a strong electric field is closed with the dielectric plate 220, the upper portion of the waveguide WG may be hollow. Of course, the dielectric plate 220 may be filled up to the top of the waveguide WG.

  As shown in FIG. 2, the coaxial tube 225 is connected to a substantially central position in the longitudinal direction A of the waveguide WG, and this position serves as a power feeding position. The outer conductor 225b of the coaxial tube 225 is constituted by a part of the waveguide member 201B, and the inner conductor 225a1 passes through the central portion of the outer conductor 225b. The lower end portion of the internal conductor 225a1 is electrically connected to the internal conductor 225a2 disposed perpendicular to the internal conductor 225a1. The internal conductor 225a2 passes through a hole opened in the dielectric plate 220 and is electrically connected to the electrode portion 201EA on the waveguide member 201A side.

  The inner conductors 225a1 and 225a2 of the coaxial tube 225 are electrically connected to one electrode portion 201EA of the plasma generating mechanism 200, and the outer conductor 225b of the coaxial tube 225 is electrically connected to the other electrode portion 201EB of the plasma generating mechanism 200. Connected. A high frequency power source 250 is connected to the upper end of the coaxial tube 225 via a matching unit 245. The high frequency power fed from the high frequency power supply 250 propagates from the center position in the longitudinal direction A to both ends of the waveguide WG via the coaxial tube 225.

  The inner conductor 225a2 penetrates the dielectric plate 220. The directions in which the inner conductors 225a2 provided in the adjacent plasma generation mechanisms 200 penetrate the dielectric plates 220 of the plasma generation mechanisms 200 are opposite to each other. Here, when high frequency waves having the same amplitude and phase are supplied to the coaxial tubes 225 of the two plasma generation mechanisms 200, the amplitudes are respectively applied to the electrode portions 201EA and 201EB of the two plasma generation mechanisms 200 as shown in FIG. Equally antiphase high frequency is applied. In the present specification, high frequency means a frequency band of 10 MHz to 3000 MHz, and is an example of electromagnetic waves. The coaxial tube 225 is an example of a transmission line that supplies a high frequency, and a coaxial cable, a rectangular waveguide, or the like may be used instead of the coaxial tube 225.

  As shown in FIG. 1, in order to prevent discharge on the side surfaces of the electrode portions 201EA and 201EB and invasion of plasma into the upper portion, the side surfaces in the width direction B of the electrode portions 201EA and 201EB are formed with the first dielectric cover 221. Covered with. As shown in FIG. 2, in order to keep the end face in the longitudinal direction A of the waveguide WG open and to prevent discharge on both side faces, both side faces in the longitudinal direction A of the flat plate portion 201W are provided with a second dielectric. Covered with a body cover 215.

  The lower surfaces of the electrode portions 201EA and 201EB are formed to be substantially flush with the lower end surface of the dielectric plate 220, but the lower end surface of the dielectric plate 220 protrudes from the lower surfaces of the electrode portions 201EA and 201EB. However, it may be recessed. The electrode parts 201EA and 201EB also serve as shower plates. Specifically, a recess is formed in the lower surface of the electrode portions 201EA and 201EB, and an electrode lid 270 for a shower plate is fitted in the recess. The electrode lid 270 is provided with a plurality of gas discharge holes, and the gas that has passed through the gas flow path is discharged from the gas discharge holes to the substrate G side. A gas nozzle made of an electrical insulator such as aluminum oxide is provided at the lower end of the gas flow path (see FIG. 4).

  In order to perform a uniform process, it is not sufficient that the plasma density is uniform. Since the gas pressure, source gas density, reaction product gas density, gas residence time, substrate temperature, and the like affect the process, they must be uniform on the substrate G. In a normal plasma processing apparatus, a shower plate is provided at a portion facing the substrate G, and gas is supplied toward the substrate. The gas flows from the center of the substrate G toward the outer periphery, and is exhausted from the periphery of the substrate. Inevitably, the pressure is higher in the central part of the substrate than in the outer peripheral part, and the residence time is longer in the outer peripheral part of the substrate than in the central part. As the substrate size increases, a uniform process cannot be performed due to the deterioration in uniformity of the pressure and residence time. In order to perform a uniform process even on a large-area substrate, it is necessary to supply gas from directly above the substrate G and simultaneously exhaust air from directly above the substrate.

  In the plasma processing apparatus 10, an exhaust slit C is provided between adjacent plasma generation mechanisms 200. That is, the gas output from the gas supply device 290 is supplied into the processing chamber from the lower surface of the plasma generation mechanism 200 through the gas flow path formed in the plasma generation mechanism 200, and is exhausted just above the substrate G. The air is exhausted upward from the slit C. The gas that has passed through the exhaust slit C flows through the first exhaust path 281 formed in the upper part of the exhaust slit C by the adjacent plasma generation mechanism 200, and between the second dielectric cover 215 and the vacuum vessel 100. It is guided to the second exhaust path 283 provided. Further, it flows downward through a third exhaust passage 285 provided on the side wall of the vacuum vessel 100 and is exhausted by a vacuum pump (not shown) provided below the third exhaust passage 285.

  A coolant channel 295 a is formed in the ceiling portion 105. The refrigerant output from the refrigerant supply device 295 flows into the refrigerant flow path 295a, thereby transferring the heat flowing from the plasma to the ceiling portion 105 side via the plasma generation mechanism 200.

  In the plasma processing apparatus 10, an impedance variable circuit 380 is provided in order to electrically change the effective height h of the waveguide WG. In addition to the coaxial tube 225 for supplying a high frequency provided at the center in the electrode longitudinal direction, two coaxial tubes 385 for connecting the two impedance variable circuits 380 are provided near both ends in the electrode longitudinal direction. ing. In order not to disturb the gas flow in the first gas exhaust path 281, the inner conductor 385 a 2 of the coaxial pipe 385 is provided above the inner conductor 225 a 2 of the coaxial pipe 225.

  As a configuration example of the variable impedance circuit 380, a configuration having only a variable capacitor, a configuration in which a variable capacitor and a coil are connected in parallel, a configuration in which a variable capacitor and a coil are connected in series, and the like can be considered.

  In the plasma processing apparatus 10, the effective height of the waveguide WG is adjusted so that the reflection viewed from the coaxial waveguide 225 is minimized when the cutoff state is reached. Further, it is preferable to adjust the effective height of the waveguide even during the process. Therefore, in the plasma processing apparatus 10, the reflectometer 300 is attached between the matching unit 245 and the coaxial tube 225 so as to monitor the state of reflection viewed from the coaxial tube 225. The detection value by the reflectometer 300 is transmitted to the control unit 305. The control unit 305 instructs to adjust the impedance variable circuit 380 based on the detected value. This adjusts the effective height of the waveguide WG to minimize reflection viewed from the coaxial tube 225. If the above control is performed, the reflection coefficient can be kept very small, so that the installation of the matching unit 245 can be omitted.

  If high-frequency waves with opposite phases are supplied to two adjacent plasma generation mechanisms 200, high-frequency waves with the same phase are applied to the two adjacent electrode portions 201EA and 201EA as shown in FIG. In this state, no high frequency electric field is applied to the exhaust slit C between the plasma generation mechanisms 200, so that plasma is not generated in this portion.

  In order to prevent an electric field from being generated in the exhaust slit C, the phase of the high frequency propagating through each of the waveguides WG of the adjacent plasma generation mechanisms 200 is shifted by 180 ° so that the high frequency electric field is applied in the opposite direction.

  As shown in FIG. 1, the inner conductor 225a2 of the coaxial tube disposed in the left plasma generating mechanism 200 and the inner conductor 225a2 of the coaxial tube disposed in the right plasma generating mechanism 200 are disposed in opposite directions. As a result, the high-frequency in-phase supplied from the high-frequency power source 250 is in reverse phase when transmitted to the waveguide WG via the coaxial tube.

  In the case where the inner conductors 225a2 are arranged in the same direction, a high frequency power supply 250 applies a high frequency of opposite phase to the adjacent electrode pairs, so that the lower surfaces of all the electrode portions 201EA and 201EB of the plasma generation mechanism 200 The formed high-frequency electric field can be in the same direction, and the high-frequency electric field can be made zero by the exhaust slit C.

First Embodiment In the plasma processing apparatus 10 having the above-described configuration, it is possible to excite uniform plasma on, for example, an electrode having a length of 2 m or more by setting the waveguide WG in a cut-off state. However, in the basic type of plasma processing apparatus as shown in FIG. 3B, the electric field strength in the sheath on the substrate surface in the width direction B of the waveguide WG has a distribution as shown in FIG. In FIG. 13, it can be seen that the electric field strength is the smallest at the center position of the first and second electrode portions EL1, EL2, and the strongest at both ends in the width direction B of the first and second electrode portions EL1, EL2. As described above, when the electric field strength changes in the width direction B, the uniformity of the plasma density in the width direction B decreases. In the structure in which the first and second electrode portions EL1 and EL2 are arranged in the width direction B while extending in the longitudinal direction A of the waveguide WG, when a gas such as SiH ₄ is supplied, the width direction The generation of plasma in B may become unstable. For this reason, in this embodiment, a plasma generation mechanism that can improve the uniformity of the plasma density in the width direction B of the waveguide WG will be described.

  FIG. 5 is a perspective sectional view of the plasma generation mechanism 400 according to the present embodiment. FIG. 6 is a perspective cross-sectional view showing the appearance of the plasma generation mechanism of FIG. 5 as viewed from the coaxial tube side. FIG. 7 is a perspective cross-sectional view showing the appearance of the plasma generation mechanism of FIG. 5 as viewed from the electrode side. FIG. 8 is a perspective view of the electrode unit. It is sectional drawing of an electrode unit. The plasma generation mechanism 400 corresponds to each of the two plasma generation mechanisms 200 shown in FIGS. 1 and 4. That is, the plasma processing apparatus according to the present embodiment is obtained by replacing the two plasma generation mechanisms 200 shown in FIGS. 1 and 4 with the plasma generation mechanism 400 shown in FIG. The plasma processing apparatus according to the present embodiment includes an adjustment mechanism for always keeping the waveguide in a cut-off state even when the load changes, that is, the two impedance variable circuits 380 and the two impedance variable circuits 380 described above. Two coaxial pipes 385 that are connected to each other are provided.

  The plasma generation mechanism 400 includes first and second waveguide members 401 and 402. The first waveguide member 401 is formed of a conductive material such as an aluminum alloy, and includes two protruding portions 401rA and 401rB arranged in parallel and a flat portion 401f extending between the two protruding portions 401rA and 401rB. The second waveguide member 402 is formed in a flat plate shape with a conductive material such as an aluminum alloy, and the first waveguide member 401 is disposed on the second waveguide member 402. A waveguide WG having two raised portions is defined between the waveguide member 401 and the waveguide member 402. Dielectric plates 421 to 423 extending in the longitudinal direction A are provided on the second waveguide member 402, and a part of the dielectric plate 421 is a lower surface of the flat end portion 401 f of the first waveguide member 401. Is in contact with The dielectric plates 421 to 423 are formed of a dielectric material such as a fluororesin. The second waveguide member 402 may be formed with a coolant channel for keeping the temperature of the electrode constant.

  A plurality of first and second coil members 410A and 410B are arranged in the two raised portions 401rA and 401rB of the waveguide WG. The first and second coil members 410A and 410B are formed of a conductive material such as an aluminum alloy, and the cross section in the direction crossing the longitudinal direction A is formed in a cylindrical shape having a rectangular shape. The first and second coil members 410A and 410B are approximately one-turn coils, and are arranged in the waveguide WG so as to generate a voltage by electromagnetic induction caused by a magnetic field in the waveguide WG. The first and second end portions 410b1 and 410b2 in the turn direction of the first coil member 410A are disposed on the dielectric plates 421 and 422 and face each other with a predetermined gap. The first and second end portions 410b1 and 410b2 in the turn direction of the second coil member 410B are disposed on the dielectric plates 423 and 421, respectively, and face each other with a predetermined gap.

  A first dielectric plate 420A is provided in the first raised portion 401rA of the first waveguide member 401 so as to penetrate the plurality of first coil members 410A. The lower end portion of the first dielectric plate 420A is inserted between the opposing first and second end portions 410b1 and 410b2 of the first coil member 410A, and the dielectric plate 421 and the dielectric plate 422 Is inserted between. A second dielectric plate 420B is provided in the second raised portion 401rB of the first waveguide member 401 so as to penetrate the plurality of second coil members 410B. The lower end of the second dielectric plate 420B is inserted between the opposing first and second ends 410b1 and 410b2 of the second coil member 410B, and the dielectric plate 421 and the dielectric plate 423 Is inserted between. The first and second dielectric plates 420A and 420B are made of a dielectric material such as a fluororesin.

  As shown in FIGS. 5 and 6, the coaxial waveguide 225 is electrically connected to the first and second waveguide members 401 and 402 at a substantially central position in the longitudinal direction A of the waveguide WG. Each is supplied with electromagnetic energy. Specifically, the coaxial waveguide 225 is provided between the first and second raised portions, and is disposed along the height direction of the waveguide WG. The lower end portion of the inner conductor 225 a penetrates the dielectric plate 421 from the height direction H and is electrically connected to the flat plate-like second waveguide member 402. The lower end portion of the outer conductor 225 a is electrically connected to the flat end portion 401 f of the first waveguide member 402.

  A plurality (eight) of electrode units 460 are arranged along the longitudinal direction A on the lower surface of the second waveguide member 402. The electrode unit 460 includes a dielectric plate 462 formed in a rectangular shape and a plurality of electrodes 461 formed on the surface of the dielectric plate 462. The dielectric plate 462 is formed of a dielectric material such as aluminum oxide, and the upper surface thereof is in contact with the lower surface of the second waveguide member 402. The plurality of electrodes 461 are made of a metal film plated on the surface of the dielectric plate 462. The plurality of electrodes 461 have a predetermined width, extend in the width direction B of the waveguide WG, and are guided. They are arranged at a predetermined pitch along the longitudinal direction A of the waveguide WG. The arrangement pitch is about 10 mm, for example.

  In the dielectric plate 462, a plurality of grooves 462t having a predetermined depth extending along the two adjacent electrodes 461 are formed between the two adjacent electrodes 461 on the surface on which the electrode 461 is formed. . The groove 462t is provided in order to reduce the parasitic capacitance between two adjacent electrodes 461. That is, by providing the groove 462t, the loss of electromagnetic energy is reduced and the efficiency can be improved.

  The dielectric plate 462 is used as a shower plate. At this time, the gas discharge hole described above is provided in the groove 462t. That is, the outlet of the gas discharge hole that penetrates the dielectric plate is formed in the groove 462t. Since the electric field in the groove 462t is weaker than the surface of the electrode 461, the discharge in the gas discharge hole can be suppressed by providing the gas discharge hole in the groove 462t.

  The plurality of electrodes 461 are electrically connected to the first and second coil members 410A and 410B by connection pins 430 formed of a conductive material such as an aluminum alloy. Specifically, as shown in FIGS. 5 and 6, the connection pin 430 connected to the first end 410b1 of the first coil member 410A includes a dielectric plate 422, a second waveguide member 402, and a dielectric. It penetrates the body plate 462 and is electrically connected to the corresponding electrode 461 among the plurality of electrodes 461. The connection pin 430 connected to the second end portion 410b2 of the second coil member 410B passes through the dielectric plate 423, the second waveguide member 402, and the dielectric plate 462, and corresponds to the plurality of electrodes 461. The electrode 461 is electrically connected. The connection pin 430 connected to the first end 410b1 of the first coil member 410A and the connection pin 430 connected to the second end 410b2 of the second coil member 410B are connected to the common electrode 461. Yes.

  Similarly, the connection pin 430 connected to the second end portion 410b2 of the first coil member 410A penetrates the dielectric plate 421, the second waveguide member 402, and the dielectric plate 462, and the plurality of electrodes 461 are connected. It is electrically connected to the corresponding electrode 461. The connection pin 430 connected to the first end 410b1 of the second coil member 410B passes through the dielectric plate 421, the second waveguide member 402, and the dielectric plate 462, and corresponds to the plurality of electrodes 461. The electrode 461 is electrically connected. The connection pin 430 connected to the second end portion 410b2 of the first coil member 410A and the connection pin 430 connected to the first end portion 410b1 of the second coil member 410B are connected to the common electrode 461. Yes. The connection pin 430 and the second waveguide member 402 are electrically separated by a dielectric 440.

  In the plasma generation mechanism 400, as shown in FIG. 10, when electromagnetic energy is supplied from the coaxial tube 225 to the plurality of electrodes 461 through the waveguide WG, two adjacent electrodes 461 in the longitudinal direction A of the waveguide WG A high frequency wave having the same amplitude and opposite phase is applied. Due to this high frequency, an electric field directed from one of the two adjacent electrodes 461 to the other is formed as indicated by an arrow in FIG. The intensity of the electric field is substantially constant in the longitudinal direction of the electrode 461, that is, in the width direction of the waveguide WG. As a result, the uniformity of the plasma density can be improved in the longitudinal direction of the electrode 461, that is, in the width direction of the waveguide WG.

  In the present embodiment, a plurality of first and second coil members 410A and 410B are arranged along the longitudinal direction A. When the plurality of coil members 410A and 410B are connected to each other, depending on conditions, a mode of propagating in the coil members 410A and 410B in the longitudinal direction A occurs, and the uniformity of plasma density in the longitudinal direction A decreases. There is a case. In the present embodiment, such mode generation can be suppressed by dividing the coil member into a plurality of parts. In addition, depending on conditions, the coil members 410A and 410B may not be divided into a plurality in the longitudinal direction A. The form of the coil members 410A and 410B is not limited to this embodiment. For example, in addition to a rectangular cross-sectional shape, various shapes such as a circle and an ellipse can be employed. Further, the coil is not limited to about one turn, and may be, for example, a half turn or a few turns.

In the first embodiment, the case where the plurality of grooves 462t are formed in the dielectric plate 462 has been described. For example, as shown in FIGS. 11 and 12, the dielectric plate 462 in which the plurality of grooves 462t are not formed. It is also possible to use.

  Although the electrode is formed of a metal film plated on the dielectric plate 462, the present invention is not limited to this, and the electrode 461 can be formed separately from the dielectric plate 462. In addition, the electrode 461 can be formed of a metal member instead of the metal film.

  In the first embodiment, the case where the waveguide WG is maintained in the cutoff state has been described. However, the electrode unit of the present invention can also be applied to a waveguide that is not in the cutoff state.

  In the first embodiment, the waveguide is a so-called double ridge type. However, the present invention is not limited to this, and the present invention can be applied to various types of waveguides.

  In the first embodiment, the dielectric plate 462 is also used as a shower plate, but it may not be used as a shower plate.

  In the first embodiment, the feeding position is the central position in the longitudinal direction of the waveguide, but the present invention is not limited to this, and can be changed as necessary. In addition, the feeding position is not limited to one place but can be provided at a plurality of places in the longitudinal direction of the waveguide.

  As mentioned above, although embodiment of this invention was described in detail, referring an accompanying drawing, this invention is not limited to this example. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

225 Coaxial tube 400 Plasma generation mechanism 410A, 410B Coil members 401, 402 Waveguide member WG Waveguide 460 Electrode unit 461 Electrode 462 Dielectric plate PS Plasma formation space

Claims (2)

A waveguide member defining a waveguide;
A transmission line for supplying electromagnetic energy into the waveguide from a predetermined feeding position in the longitudinal direction which is the waveguide direction of the waveguide;
Electromagnetic energy is supplied through the waveguide, and has a plurality of electric field forming electrodes arranged to face the plasma forming space,
The plurality of electrodes are arranged along a longitudinal direction of the waveguide,
Each of the plurality of electrodes is orthogonal to the longitudinal direction of the waveguide and extends in a width direction that is a direction along the wavefront of the electromagnetic wave. A plasma processing method for performing plasma processing using the plasma processing apparatus according to claim 1.

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