WO2014002493A1 - Plasma-generating device and method for generating plasma - Google Patents

Plasma-generating device and method for generating plasma Download PDF

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Publication number
WO2014002493A1
WO2014002493A1 PCT/JP2013/003996 JP2013003996W WO2014002493A1 WO 2014002493 A1 WO2014002493 A1 WO 2014002493A1 JP 2013003996 W JP2013003996 W JP 2013003996W WO 2014002493 A1 WO2014002493 A1 WO 2014002493A1
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WO
WIPO (PCT)
Prior art keywords
plasma
magnetic field
chamber
coil
vacuum chamber
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PCT/JP2013/003996
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French (fr)
Japanese (ja)
Inventor
康規 田中
克弥 倉石
美香 赤尾
豊信 吉田
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国立大学法人金沢大学
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Application filed by 国立大学法人金沢大学 filed Critical 国立大学法人金沢大学
Priority to JP2014522433A priority Critical patent/JP5959025B2/en
Publication of WO2014002493A1 publication Critical patent/WO2014002493A1/en

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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
    • C23C16/50—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating using electric discharges
    • C23C16/505—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating using electric discharges using radio frequency discharges
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/32—Gas-filled discharge tubes
    • H01J37/32009—Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources
    • H01J37/32082—Radio frequency generated discharge
    • H01J37/321—Radio frequency generated discharge the radio frequency energy being inductively coupled to the plasma
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/32—Gas-filled discharge tubes
    • H01J37/32009—Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources
    • H01J37/32082—Radio frequency generated discharge
    • H01J37/321—Radio frequency generated discharge the radio frequency energy being inductively coupled to the plasma
    • H01J37/3211—Antennas, e.g. particular shapes of coils
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/46—Generating plasma using applied electromagnetic fields, e.g. high frequency or microwave energy
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/46—Generating plasma using applied electromagnetic fields, e.g. high frequency or microwave energy
    • H05H1/4645—Radiofrequency discharges
    • H05H1/4652—Radiofrequency discharges using inductive coupling means, e.g. coils

Definitions

  • the present invention relates to a plasma generation apparatus and a plasma generation method.
  • High-frequency induction thermal plasma ICTP Inductively Coupled Thermal Plasma
  • thermal plasma has a gas temperature of several thousand to several tens of thousands K (Kelvin), and has extremely high enthalpy and high reactivity. Furthermore, since a clean thermal plasma space can be formed without an electrode, impurities mixed in the thermal plasma can be extremely reduced. Utilizing these advantages, application to surface treatment including surface modification treatment or thin film generation treatment is expected.
  • FIG. 19 is an explanatory diagram of a conventional plasma generator 1001.
  • the conventional plasma generator includes a cylindrical quartz tube arranged in a double manner and a coil wound around the quartz tube.
  • 20 is a cross-sectional view taken along the line AA ′ of FIG. 19.
  • the conventional plasma generating apparatus includes double quartz tubes 1101 a and 1101 b and a coil 1102.
  • cooling water 1101w is caused to flow in the space between the quartz tube 1101a and the quartz tube 1101b, and the quartz tube 1101a is maintained at about 300K.
  • a magnetic field is generated inside the coil by applying a high-frequency current 1107 to the coil 1102, and an electric field having a shape surrounding the magnetic field is generated.
  • thermal plasma 1108 is generated inside the quartz tube. That is, a thermal plasma having a shape surrounding the central axis of the coil is generated inside the quartz tube.
  • the quartz tube may be damaged.
  • FIG. 21 is a cross-sectional view corresponding to FIG. 20 in the plasma generator disclosed in Patent Document 1. According to the technique disclosed in Patent Document 1, a large-area substrate can be etched at a time by thermal plasma.
  • a plasma generator using a quartz tube having a shape different from the above a plasma generator including a quartz tube formed by bonding inexpensive quartz plates and a coil wound around the quartz tube is conceivable.
  • a plasma generator disclosed in Patent Document 1 As shown in FIG. 21, when the thermal plasma 1208 is generated by the plasma generator disclosed in Patent Document 1, the thermal plasma 1208 has a shape surrounding the central axis of the coil. At this time, if the high-temperature thermal plasma contacts the flat portion of the quartz tube 1201a, the quartz tube may be damaged. Therefore, also in the plasma generator disclosed in Patent Document 1, it is difficult to stably maintain the thermal plasma generated in the interior, as in the conventional plasma generator. That is, the above problem cannot be solved by the plasma generator disclosed in Patent Document 1.
  • the present invention has been made to solve the above problems, and an object of the present invention is to provide a plasma generator and the like capable of stably generating thermal plasma.
  • a plasma generator is a flat chamber, a chamber in which plasma gas flows in a predetermined direction inside the chamber, and the chamber with respect to the chamber.
  • a magnetic field application unit configured to generate thermal plasma in the chamber by applying a crossing magnetic field in a direction orthogonal to a predetermined direction;
  • the plasma generator can stably generate thermal plasma.
  • the magnetic field application unit may include a coil that applies a cross-seeding magnetic field in a direction orthogonal to the predetermined direction with respect to the chamber.
  • thermal plasma can be generated inside the chamber.
  • the magnetic field application unit may further include a magnetic core whose end is disposed in the vicinity of the chamber, and the coil may be wound around a part of the magnetic core.
  • the magnetic field generated in the coil can be transmitted to the vicinity of the chamber by the magnetic core (ferrite core).
  • the thermal plasma can be generated in the vacuum chamber by the magnetic field transmitted to the vicinity of the chamber by the ferrite core. Therefore, even when the chamber is disposed at a position away from the coil, the plasma generator can stably generate thermal plasma.
  • the magnetic core may have a U shape, and both end portions of the magnetic core may be disposed so as to sandwich the chamber from the thickness direction.
  • a uniform magnetic field can be generated in a concentrated manner in the thickness direction of the chamber by transmitting the magnetic field generated in the coil by the ferrite core to the vicinity of the chamber.
  • thermal plasma can be stably generated over a wide range in the thickness direction of the chamber.
  • the magnetic core may have a shape in which a cross-sectional area of a portion disposed in the vicinity of the chamber is smaller than a cross-sectional area of a portion around which the coil is wound.
  • the magnetic field generated in the coil can be transmitted to the vicinity of the chamber by the ferrite core, and the magnetic field can be concentrated in the vicinity of the ferrite core. That is, a strong magnetic field can be generated locally in the chamber even when the current output is small. Therefore, the plasma generator can stably generate thermal plasma with relatively small electric power.
  • the magnetic field application unit may include a plurality of coils that are arranged so as to sandwich the chamber and apply a cross-seeding magnetic field in a direction orthogonal to the predetermined direction with respect to the chamber.
  • a uniform magnetic field can be concentrated and generated in the thickness direction of the chamber by the two coils.
  • thermal plasma can be stably generated over a wide range in the thickness direction of the chamber.
  • the magnetic field application unit includes a first application unit and a second application unit, and the first application unit applies a cross-seed magnetic field to the chamber in a first period, and a second period different from the first period.
  • the second application unit may apply a cross-seeding magnetic field to the chamber.
  • a magnetic field can be locally applied to a plurality of locations in the flat direction of the chamber using a plurality of coils.
  • each of the plurality of coils can be realized by a current source having an output capacity equivalent to that of the prior art by sequentially applying a high-frequency current to each of the coils at different periods. That is, the plasma generator can generate thermal plasma without using an expensive current source having a large output capacity. Thus, the plasma generator can stably generate a large area of thermal plasma.
  • the magnetic field application unit applies the cross-seeding magnetic field in which f ⁇ B is within a range of 3000 T / s to 6500 T / s, where f is the frequency of the cross-seeding magnetic field and B is the magnetic flux density. You may do that.
  • the plasma generator can generate the thermal plasma by the cross magnetic field of the magnetic flux density and the frequency of the vapor.
  • the plasma generation method includes an installation step of installing a chamber having a flat shape, in which plasma gas flows in a predetermined direction, and the predetermined chamber with respect to the chamber. Applying a cross-seed magnetic field in a direction perpendicular to the direction to generate a thermal plasma in the chamber.
  • FIG. 1 is a perspective view of the plasma generator according to the first embodiment.
  • FIG. 2 is a side view of the plasma generating apparatus according to the first embodiment.
  • FIG. 3 is a front view of the plasma generating apparatus according to the first embodiment.
  • FIG. 4 is a plan view of the upper flange of the plasma generating apparatus according to the first embodiment.
  • FIG. 5 is a plan view of the lower flange of the plasma generating apparatus according to the first embodiment.
  • FIG. 6 is a schematic diagram of the plasma generator according to the first embodiment.
  • FIG. 7 is a schematic diagram of the plasma generator according to the second embodiment.
  • FIG. 8A is an example of plasma generation conditions and physical quantities during plasma generation in the second exemplary embodiment.
  • FIG. 8A is an example of plasma generation conditions and physical quantities during plasma generation in the second exemplary embodiment.
  • FIG. 8B shows another example of plasma generation conditions and physical quantities during plasma generation in the second exemplary embodiment.
  • FIG. 9 is a schematic diagram of the plasma generator according to the third embodiment.
  • FIG. 10 shows an example of a plasma generation method in the plasma generation apparatus according to the fourth embodiment.
  • FIG. 11 is a perspective view of the plasma generating apparatus according to the fifth embodiment.
  • FIG. 12 is a side view of the plasma generating apparatus according to the fifth embodiment.
  • FIG. 13 is a front view of the plasma generator according to the fifth embodiment.
  • FIG. 14 is a schematic diagram of a plasma generator according to the fifth embodiment.
  • FIG. 15 is an example of the ferrite specifications of the plasma generating apparatus according to the fifth embodiment.
  • FIG. 16 is an example of plasma generation conditions and physical quantities during plasma generation in the fifth embodiment.
  • FIG. 17 is a schematic diagram of a plasma generator according to the sixth embodiment.
  • FIG. 18 is a schematic diagram of a plasma generator according to the seventh embodiment.
  • FIG. 19 is an explanatory diagram of a conventional plasma generator.
  • FIG. 20 is an example of a cross-sectional view of a conventional plasma generator.
  • FIG. 21 is another example of a cross-sectional view of a conventional plasma generator.
  • FIG. 1 is a perspective view of the plasma generator according to the first embodiment.
  • the plasma generator according to Embodiment 1 includes a vacuum chamber 11 and a coil 12.
  • the vacuum chamber is also simply referred to as “chamber”.
  • the vacuum chamber 11 includes a flat quartz tube 10 (hereinafter also simply referred to as a quartz tube), an upper flange 13, and a lower flange 14.
  • the vacuum chamber 11 is connected to a vacuum pump (not shown) or the like, and the inside can be evacuated.
  • Plasma gas is introduced into the vacuum chamber 11, and thermal plasma is generated when predetermined physical conditions are met.
  • the vacuum chamber 11 is kept at approximately 300 K (Kelvin).
  • the dimensions of the quartz tube 10 are, for example, a width (y direction) of 120 mm, a depth (x direction) of 20 mm, and a height (z direction) of 100 mm.
  • the thickness direction of the flat shape is the x direction.
  • the thickness of the quartz tube 10 is, for example, 5 mm.
  • the plasma gas is a gas component of thermal plasma, for example, a mixed gas of Ar (main component), CH 4 and H 2 .
  • the coil 12 is disposed at a position adjacent to the vacuum chamber in the thickness direction.
  • the coil 12 is connected to an inverter circuit (not shown) that operates as a current source, and is applied with a high-frequency current having a constant amplitude of several hundred kHz.
  • the coil 12 generates a thermal plasma in the vacuum chamber 11 by generating a crossing magnetic field (hereinafter also simply referred to as a magnetic field) in the vacuum chamber 11 by a high-frequency current flowing in the coil 12.
  • Thermal plasma cannot follow such a high-frequency electric field change and behaves like a conductive metal column. That is, an eddy current flows in the plasma in the circumferential direction due to electromagnetic induction, and thermal plasma is generated by Joule heat generated by this current.
  • the coil 12 applies a crossing magnetic field in which f ⁇ B is within a range of 3000 T / s or more and 6500 T / s or less when the frequency of the crossing magnetic field is f and the magnetic flux density is B.
  • a cross-seeding magnetic field is realized, for example, by setting the frequency f to 50 kHz to 500 kHz and the magnetic flux density B to 13 mT to 130 mT.
  • the coil 12 in FIG. 1 has a cylindrical shape with a number of turns of about 5 turns, the number of turns and the shape are not limited thereto. The number of turns may be any number of turns greater than one.
  • the shape may be any shape such as a pancake shape (swirl shape), a saw shape, a star shape, a polygonal shape, an elliptical shape, a meander shape, or a shape having characteristics of those shapes.
  • the coil 12 corresponds to a magnetic field application unit.
  • FIG. 2 is a side view of the plasma generator according to the first embodiment.
  • the constituent elements shown in FIG. 2 are the same as the constituent elements shown in FIG.
  • FIG. 3 is a front view of the plasma generator according to the first embodiment.
  • the constituent elements shown in FIG. 3 are the same as the constituent elements shown in FIG.
  • FIG. 4 is a plan view of the upper flange 13 of the plasma generator according to the first embodiment.
  • the upper flange 13 has four gas holes 13b having a diameter of about 1 mm on the short side and 32 pieces on the long side so that the plasma gas can flow in a sheath shape to the inner wall surface of the quartz tube 10. 36 in total. Moreover, it has the gas path
  • the quartz tube 10 is disposed at a position indicated by a broken line 13c.
  • FIG. 5 is a plan view of the lower flange 14 of the plasma generator according to the first embodiment.
  • the lower flange 14 is connected to a vacuum pump (not shown) or the like, and has an opening 14h for evacuating the inside of the vacuum chamber 11.
  • the quartz tube 10 is disposed at a position indicated by 14c.
  • FIG. 6 is a schematic diagram of the plasma generator 1 according to the first embodiment.
  • the vacuum chamber 11 and the coil 12 shown in FIG. 6 are the same as those shown in FIG. Detailed configuration is omitted.
  • a high-frequency magnetic field is applied to the inside of the vacuum chamber 11 in the x direction by causing the high-frequency current 17 to flow through the coil 12 from the current source.
  • This magnetic field generates a thermal plasma 18 having a shape surrounding the magnetic field.
  • the thermal plasma 18 is generated in the vacuum chamber 11 at a position close to the coil 12 where the magnetic field applied by the coil 12 is stronger.
  • a flat vacuum chamber such as a quartz tube formed from a non-cylindrical quartz plate is used, and thermal plasma is generated inside the vacuum chamber. Can be generated.
  • the thermal plasma which spreads in the direction (flat direction) orthogonal to the thickness direction in a flat vacuum chamber can be generated. Therefore, by making the vacuum chamber sufficiently large in the flat direction, it is possible to prevent thermal plasma from contacting the flat portion of the quartz tube. Therefore, the plasma generator can stably generate thermal plasma.
  • thermal plasma can be generated inside the chamber.
  • Embodiment 2 In Embodiment 2, an example of a plasma generator that can generate thermal plasma more stably than Embodiment 1 by arranging coils so as to sandwich a vacuum chamber is shown.
  • FIG. 7 is a schematic diagram of plasma generators 2a and 2b according to the second embodiment.
  • the plasma generator 2a includes a vacuum chamber 21, a coil 22a, and a coil 22b.
  • the vacuum chamber 21 may be the same as the vacuum chamber 11.
  • a high frequency current 27a is applied to the coil 22a.
  • a high frequency current 27a is applied to the coil 22b.
  • the high-frequency current 27a and the high-frequency current 27 are controlled so that the period and phase are equal.
  • a plasma generator 2b in which a coil 22a and a coil 22b are connected in series and a high-frequency current 27 is supplied from a single current source may be used.
  • this corresponds to the case where the high-frequency current 27a and the high-frequency current 27 are controlled so as to have the same amplitude as well as the period and phase.
  • the case where the coil 22a and the coil 22b are connected in series and the high frequency current 27 is supplied from a single current source is demonstrated.
  • a high frequency current 27 is applied to the coil 22a and the coil 22b, a thermal plasma 28 is generated in the vacuum chamber 21.
  • Predetermined physical conditions such as the high-frequency current 27 will be described later.
  • FIG. 8A is an example of plasma generation conditions and physical quantities during plasma generation in the second exemplary embodiment.
  • FIG. 8A shows the conditions of the DC voltage VDC and the DC current IDC input to the inverter circuit (current source), the frequency f of the AC current output from the inverter circuit (current source), the active power P, and the vacuum chamber.
  • the pressure in 21 and a gas flow rate are shown.
  • (B) to (e) of FIG. 8A are examples of a power supply response and a temperature change with time when thermal plasma is generated. Specifically, (b) voltage Vinv and current Iinv applied to the coil 22a and coil 22b, (c) effective value Vrms and effective value Irms of current applied to the coil 22a and coil 22b, (d) Active power P and (e) temperature [K]. As shown in FIG. 8A, it is confirmed that the plasma generator according to the present embodiment can generate and maintain 6600 K thermal plasma with an output of 6.8 kW.
  • the first application step and the second application step are such that the intensity of the first wavelength component included in the emission spectrum differs by a predetermined value or more between the first application step and the second application step. It may be repeated.
  • the surface temperature of a to-be-processed object is maintained at the temperature which a to-be-processed object does not receive a thermal damage.
  • the active chemical species (radicals) in the thermal plasma can be increased, and two processes for efficiently performing the surface treatment can be performed alternately in synchronization with the change of the magnetic field applied to the thermal plasma. Therefore, thermal damage to the object to be processed can be suppressed, and surface treatment with thermal plasma can be performed at a higher speed.
  • FIG. 8B shows the generation conditions of the thermal plasma generated in this way.
  • FIG. 8B shows another example of plasma generation conditions and physical quantities during plasma generation in the second exemplary embodiment.
  • 8A shows the conditions of the DC voltage VDC and the DC current IDC input to the inverter circuit (current source), the frequency f of the AC current output from the inverter circuit (current source), the active power P, and the inside of the vacuum chamber 21.
  • FIG. Gas flow rate, modulation signal of high-frequency current, and modulation signal frequency.
  • SCL Tin Current Level
  • DF Duty factor
  • the modulation signal is a ratio of time during which a current having a large amplitude with respect to the modulation period is applied.
  • FIG. 8B are examples of a power supply response and a temperature change with time when thermal plasma is generated. Specifically, (b) the modulation signal voltage, (c) the voltage Vinv and current Iinv applied to the coil 22a and the coil 22b, (d) the effective value Vrms and current of the voltage applied to the coil 22a and the coil 22b. RMS value Irms, (e) active power P, and (f) temperature [K] at three locations ((1), (2) and (3)) in the vacuum chamber. As shown in FIG. 8B, the plasma generator according to the present embodiment generates a thermal plasma of approximately 9000 K with an output of 8.9 kW by applying a high-frequency current having two amplitudes to the coil while switching. It is confirmed that it can be maintained.
  • a uniform magnetic field can be generated in a concentrated manner in the thickness direction of the vacuum chamber by two coils.
  • thermal plasma can be stably generated over a wide range in the thickness direction of the vacuum chamber.
  • Embodiment 3 an example of a plasma generator capable of generating thermal plasma in a wider space than Embodiment 1 by arranging coils at a plurality of locations adjacent to the vacuum chamber will be described.
  • FIG. 9 is a schematic diagram of the plasma generator 3 according to the second embodiment.
  • the plasma generator 3 includes a vacuum chamber 31, a coil 32a, a coil 32b, and a coil 32c.
  • the vacuum chamber 31 is wider than the vacuum chamber 11 in the z direction.
  • the vacuum chamber 31 may have a shape wider than the vacuum chamber 11 in the y direction.
  • the high frequency current 37a is applied to the coil 32a.
  • a high frequency current 37a is applied to the coil 32b.
  • a high frequency current 37c is applied to the coil 32c.
  • the high-frequency current 37a, the high-frequency current 37b, and the high-frequency current 37c are controlled so that the period and phase are equal.
  • the coil 32a, the coil 32b, and the coil 32c may be connected in series, and the high frequency current 37 may be supplied from a single current source.
  • this corresponds to the case where the high-frequency current 37a, the high-frequency current 37b, and the high-frequency current 37c are controlled to have the same amplitude as well as the period and phase.
  • the case where the coil 32a, the coil 32b, and the coil 32c are connected in series and the high frequency current 37 is supplied from a single current source is demonstrated.
  • the features of the plasma generator of this embodiment will be described while comparing with the conventional plasma generator.
  • Even if a large vacuum chamber and coil are used in a conventional plasma generator it is difficult to generate thermal plasma over a wide area as in this embodiment. This is because the magnetic field generated by the large coil and the electric field generated by the magnetic field are present in a wide space in the large quartz tube, so that the density of the magnetic field and electric field is reduced and thermal plasma cannot be generated.
  • thermal plasma is generated locally by applying an electric field and a magnetic field to a local region in a wide space in the vacuum chamber. By generating this local thermal plasma at a plurality of locations, a wide range of thermal plasma can be generated.
  • the plasma generation apparatus according to the present embodiment can realize a large processing area that cannot be realized by the conventional plasma generation apparatus.
  • the thermal plasma 38 can be generated in a wide range in the z direction (or y direction) in the vacuum chamber 31. If such a wide range of thermal plasma is used, it is possible to perform surface treatment using thermal plasma on a sample having a large surface area.
  • the number of coils was demonstrated in FIG. 9 as three, the number of coils may be arbitrary numbers 2 or more. In that case, the same control can be performed on each coil. As a result, thermal plasma can be generated in a wider space in the vacuum chamber, and surface treatment can be performed on a sample having a larger surface area.
  • a support bar or a partition plate for maintaining the strength may be inserted into the vacuum chamber 31.
  • a support bar or a partition plate for maintaining the strength may be inserted into the vacuum chamber 31.
  • the vacuum chamber 31 wider than the vacuum chamber 11 is used.
  • a wide vacuum chamber (not shown) by arranging a plurality of vacuum chambers 11 side by side.
  • the thickness of the quartz tube can be suppressed as compared with the vacuum chamber 31 of the same size.
  • a 10 mm thick quartz tube needs to be used for the vacuum chamber 31 of a quartz tube of 1000 mm ⁇ 100 mm ⁇ 20 mm.
  • a quartz tube used in a wide vacuum chamber using a 1000 mm ⁇ 100 mm ⁇ 20 mm quartz tube formed by arranging 10 100 mm ⁇ 100 mm ⁇ 20 mm vacuum chambers 11 may be about 3 mm thick.
  • water cooling is easy.
  • the wide vacuum chamber can generate thermal plasma having a length in the longitudinal direction exceeding several meters.
  • a magnetic field can be locally applied to a plurality of locations in the flat direction of the vacuum chamber using a plurality of coils.
  • each of the plurality of coils can be realized by a current source having an output capacity equivalent to that of the prior art by sequentially applying a high-frequency current to each of the coils at different periods. That is, in this plasma generator, thermal plasma can be generated without using an expensive current source with a large output capacity. Thus, the plasma generator can stably generate a large area of thermal plasma.
  • an inverter circuit (current source) having an output capacity equivalent to the conventional one is used by arranging coils at a plurality of locations adjacent to the vacuum chamber and sequentially applying a current to the plurality of coils.
  • An example of a plasma generator capable of generating thermal plasma over a larger area than the plasma generator 1 of the first embodiment will be described.
  • FIG. 10 is a schematic diagram of a plasma generation method in the plasma generation apparatus 3 according to the third embodiment.
  • the plasma generator 3 shown in FIG. 10 is the same as that described in the second embodiment.
  • a high frequency current 37a, a high frequency current 37b, and a high frequency current 37c are applied to the coil 32a, the coil 32b, and the coil 32c, respectively.
  • a high frequency current 37a is applied to the coil 32a as shown in FIG.
  • the thermal plasma 38a is generated at a position near the coil 32a in the vacuum chamber 31.
  • a high frequency current 37b is applied to the coil 32b.
  • the thermal plasma 38b is generated at a position near the coil 32b in the vacuum chamber 31.
  • a high frequency current 37c is applied to the coil 32c.
  • the thermal plasma 38c is generated at a position near the coil 32c in the vacuum chamber 31.
  • thermal plasma can be sequentially generated in a plurality of portions in the vacuum chamber 31.
  • the number of coils may be an arbitrary number of two or more.
  • Embodiment 5 when a coil and a vacuum chamber are arranged at positions separated from each other, an example of a plasma generating apparatus capable of transmitting a magnetic field generated by a coil into the vacuum chamber and generating thermal plasma in the vacuum chamber Indicates.
  • FIG. 11 is a schematic diagram of the plasma generator 4 according to the fourth embodiment.
  • the plasma generator 4 shown in FIG. 11 includes a vacuum chamber 41, a coil 42, and a ferrite core 45.
  • the vacuum chamber 41 and the coil 42 are equivalent to the vacuum chamber 11 and the coil 12 in the first embodiment, respectively.
  • the ferrite core 45 is U-shaped, and both ends thereof are arranged in the vicinity of the vacuum chamber 41.
  • the coil 42 is wound around a part of the ferrite core 45. With this configuration, the magnetic field generated by the coil 42 can be transmitted to the vicinity of the vacuum chamber 41.
  • both ends of the U-shaped ferrite core are disposed in the vicinity of both side surfaces of the vacuum chamber 41, only one end of the ferrite core is disposed in the vicinity of the vacuum chamber 41.
  • the ferrite core 45 does not need to be U-shaped, and may be a linear shape, a curved shape, or an arbitrary shape combining them.
  • the ferrite core 45 is an example of a magnetic core.
  • the ferrite core 45 is implement
  • FIG. 12 is a side view of the plasma generator according to the fifth embodiment.
  • the constituent elements shown in FIG. 12 are the same as the constituent elements shown in FIG.
  • FIG. 13 is a front view of the plasma generator according to the fifth embodiment.
  • the constituent elements shown in FIG. 13 are the same as the constituent elements shown in FIG.
  • FIG. 14 is a schematic diagram of the plasma generator 4 according to the fifth embodiment.
  • the vacuum chamber 41, the coil 42, and the ferrite core 45 shown in FIG. 14 are the same as those shown in FIG. Detailed configuration is omitted.
  • FIG. 15 is an example of plasma generation conditions and physical quantities during plasma generation in the fifth embodiment.
  • FIG. 15A shows the conditions of the DC voltage VDC and the DC current IDC input to the inverter circuit (current source), the frequency f of the AC current output from the inverter circuit (current source), the effective power P, and the inside of the vacuum chamber 41.
  • FIG. Pressure and gas flow rate are shown.
  • (B) to (e) of FIG. 15 are examples of a power supply response and a temperature change with time when thermal plasma is generated. Specifically, (b) voltage Vinv and current Iinv applied to the coil 42, (c) effective value Vrms and effective value Irms of voltage applied to the coil 42, (d) active power P, and (E) Temperature [K]. As shown in FIG. 15, it is confirmed that the plasma generator according to the present embodiment can generate and maintain a thermal plasma of 5000K with an output of 1.9 kW.
  • the manufacturing cost of the plasma generating apparatus according to the present embodiment is the manufacturing cost of the plasma generating apparatus according to the first embodiment. Is equivalent to That is, according to the plasma generator according to the present embodiment, the coil can be arranged at a position away from the vacuum chamber without significantly increasing the manufacturing cost.
  • the plasma generator of one aspect of the present invention when the vacuum chamber is disposed at a position away from the coil, the magnetic field generated inside the coil is moved to the vicinity of the vacuum chamber by the ferrite core. I can tell you. A thermal plasma can be generated in the vacuum chamber by the magnetic field transmitted to the vicinity of the vacuum chamber by the ferrite core. Therefore, even when the vacuum chamber is disposed at a position away from the coil, the plasma generator can stably generate thermal plasma.
  • a uniform magnetic field can be generated in a concentrated manner in the thickness direction of the vacuum chamber.
  • thermal plasma can be stably generated over a wide range in the thickness direction of the vacuum chamber.
  • Embodiment 6 an example of a plasma generator capable of concentrating a magnetic field generated by a coil and transmitting it to the vacuum chamber to generate thermal plasma in the vacuum chamber will be described.
  • FIG. 14 is a schematic diagram of the plasma generator 5 according to the sixth embodiment.
  • the plasma generator 5 shown in FIG. 14 includes a vacuum chamber 51, a coil 52, and a ferrite core 55.
  • the vacuum chamber 51 and the coil 52 are equivalent to the vacuum chamber 11 and the coil 12 in the first embodiment, respectively.
  • the ferrite core 55 is arranged in the vicinity of the vacuum chamber 51 in the same manner as the ferrite core 45 of the fifth embodiment, and a coil 52 is wound around a part thereof.
  • the difference between the ferrite core 55 and the ferrite core 45 is that the cross-sectional area of the end disposed in the vicinity of the vacuum chamber 51 is smaller than the cross-sectional area at the position where the coil 52 is wound. That is, the ferrite core 55 is thinner at a position near the vacuum chamber 51 than a position where the coil is wound.
  • the magnetic field generated in the coil is transmitted to the vicinity of the vacuum chamber by the ferrite core, and the magnetic field is concentrated in the vicinity of the ferrite core. it can. That is, a strong magnetic field can be locally generated in the vacuum chamber even when the output of current is small. Therefore, the plasma generator can stably generate thermal plasma with relatively small electric power.
  • Embodiment 7 an example of a plasma generator capable of generating a thermal plasma in a wide space in a vacuum chamber by dispersing a magnetic field generated by a coil to generate a magnetic field at a plurality of locations in the vacuum chamber will be described.
  • FIG. 9 is a schematic diagram of a plasma generator according to a seventh embodiment.
  • the plasma generator 6 shown in FIG. 15 includes a vacuum chamber 61, a coil 62, and a ferrite core 65.
  • the vacuum chamber 61 is wider than the vacuum chamber 11 in the z direction.
  • the vacuum chamber 61 may have a shape wider than the vacuum chamber 11 in the y direction.
  • the ferrite core 65 has three sets (six) of protrusions (65a, 65b, 65c, 65d, 65e, and 65f) that are arranged to face each other with the vacuum chamber interposed therebetween.
  • the magnetic field generated by the coil 62 can be applied to a plurality of locations in the vacuum chamber 61 in a concentrated manner.
  • the thermal plasma 68 can be generated in a wide range in the z direction.
  • the material of the vacuum chamber is not limited to the quartz tube.
  • ceramic having strength and thermal shock resistance for example, Si 3 O 4
  • alumina can be used.
  • the plasma generator and the plasma generation method according to one embodiment of the present invention can be applied to surface treatment including surface modification treatment or thin film production treatment.
  • Plasma generator 10 40, 1101a, 1101b, 1201a, 1201b Quartz tube 11, 21, 31, 41, 51, 61 Vacuum chamber 12, 22a, 22b, 32a, 32b, 32c, 42, 52, 62, 1102, 1202 Coil 13, 43 Upper flange 14, 44 Lower flange 17, 27, 27a, 37, 37a, 37b, 37c, 47, 57, 67, 1107 High frequency current 18 28, 38, 38a, 38b, 38c, 48, 58, 68, 1108, 1208 Thermal plasma 45, 55, 65 Ferrite core 65a, 65b, 65c, 65d, 65e, 65f Protrusion

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Abstract

A plasma-generating device (1) is a flat-shaped vacuum chamber (11), the device being provided with: a vacuum chamber (11) through the interior of which plasma gas flows in a predetermined direction, and a coil (12) for generating thermal plasma within the vacuum chamber (11) by applying an alternating magnetic field to the vacuum chamber (11) in a direction perpendicular to the predetermined direction.

Description

プラズマ発生装置、および、プラズマ発生方法Plasma generator and plasma generation method
　本発明は、プラズマ発生装置、および、プラズマ発生方法に関する。 The present invention relates to a plasma generation apparatus and a plasma generation method.
　高周波誘導熱プラズマＩＣＴＰ（Inductively Coupled Thermal Plasma）（以降、単に熱プラズマ）は、ガス温度が数千から数万Ｋ（ケルビン）となり、エンタルピーが極めて高く反応性が高い。さらに無電極でクリーンな熱プラズマ空間を形成できるので、熱プラズマに混入する不純物を極めて少なくすることができる。これらの利点を生かして、表面改質処理または薄膜生成処理を含む表面処理などへの応用が期待されている。 High-frequency induction thermal plasma ICTP (Inductively Coupled Thermal Plasma) (hereinafter simply thermal plasma) has a gas temperature of several thousand to several tens of thousands K (Kelvin), and has extremely high enthalpy and high reactivity. Furthermore, since a clean thermal plasma space can be formed without an electrode, impurities mixed in the thermal plasma can be extremely reduced. Utilizing these advantages, application to surface treatment including surface modification treatment or thin film generation treatment is expected.
　図１９は、従来のプラズマ発生装置１００１の説明図である。図１９に示されるように、従来のプラズマ発生装置は、二重に配置される円筒形状の石英管と、当該石英管に巻回されたコイルとを備える。図２０は、図１９のＡＡ’断面の断面図である。図２０に示されるように、従来のプラズマ発生装置は、二重の石英管１１０１ａ及び１１０１ｂと、コイル１１０２とを備える。また、石英管１１０１ａと石英管１１０１ｂとの間の空間には冷却水１１０１ｗが流され、石英管１１０１ａをほぼ３００Ｋに保つ。 FIG. 19 is an explanatory diagram of a conventional plasma generator 1001. As shown in FIG. 19, the conventional plasma generator includes a cylindrical quartz tube arranged in a double manner and a coil wound around the quartz tube. 20 is a cross-sectional view taken along the line AA ′ of FIG. 19. As shown in FIG. 20, the conventional plasma generating apparatus includes double quartz tubes 1101 a and 1101 b and a coil 1102. In addition, cooling water 1101w is caused to flow in the space between the quartz tube 1101a and the quartz tube 1101b, and the quartz tube 1101a is maintained at about 300K.
　従来のプラズマ発生装置１００１において、石英管内部にプラズマガスを導入した後で、コイル１１０２に高周波電流１１０７を印加することによりコイル内部に磁界が発生し、その磁界を取り巻くような形状の電界が発生し、その電界により電子が加速されることにより石英管内部に熱プラズマ１１０８が発生する。つまり、石英管内部にコイルの中心軸を取り巻くような形状の熱プラズマが発生する。このとき、高温の熱プラズマが石英管に接触すると石英管を破損するおそれがある。 In the conventional plasma generator 1001, after introducing a plasma gas into the quartz tube, a magnetic field is generated inside the coil by applying a high-frequency current 1107 to the coil 1102, and an electric field having a shape surrounding the magnetic field is generated. As the electrons are accelerated by the electric field, thermal plasma 1108 is generated inside the quartz tube. That is, a thermal plasma having a shape surrounding the central axis of the coil is generated inside the quartz tube. At this time, if the high-temperature thermal plasma contacts the quartz tube, the quartz tube may be damaged.
　一方、熱プラズマによるエッチング処理を想定して、扁平な円筒形状の石英管の内部に熱プラズマを発生させるプラズマ発生装置が開示されている（例えば、特許文献１参照）。図２１は、特許文献１に開示されるプラズマ発生装置における、図２０に対応する断面図である。特許文献１に開示される技術によれば、熱プラズマにより大面積の基板を一度にエッチング処理することができる。 On the other hand, a plasma generating apparatus that generates thermal plasma inside a flat cylindrical quartz tube assuming an etching process using thermal plasma is disclosed (for example, see Patent Document 1). FIG. 21 is a cross-sectional view corresponding to FIG. 20 in the plasma generator disclosed in Patent Document 1. According to the technique disclosed in Patent Document 1, a large-area substrate can be etched at a time by thermal plasma.
米国特許第６２１８６４０号明細書US Pat. No. 6,218,640
　従来の円筒形状の石英管による真空チャンバで発生させた熱プラズマを、安定的に維持するのは難しいという問題がある。なぜなら、高温の熱プラズマが石英管に接触すると石英管を破損するからである。 There is a problem that it is difficult to stably maintain a thermal plasma generated in a vacuum chamber using a conventional cylindrical quartz tube. This is because the quartz tube is damaged when the high temperature thermal plasma comes into contact with the quartz tube.
　上記と異なる形状の石英管を用いるプラズマ発生装置として、廉価な石英板を張り合わせて形成される石英管と、当該石英管に巻回されたコイルとを備えるプラズマ発生装置が考えられる。このようなプラズマ発生装置の一例として、特許文献１に開示されるプラズマ発生装置がある。図２１に示されるように、特許文献１に開示されるプラズマ発生装置によって熱プラズマ１２０８を発生させると、熱プラズマ１２０８はコイルの中心軸を取り巻くような形状になる。このとき、石英管１２０１ａの平面部分に高温の熱プラズマが接触すると、石英管が破損するおそれがある。よって、特許文献１に開示されるプラズマ発生装置においても、従来のプラズマ発生装置と同様に、その内部に発生させる熱プラズマを安定的に維持することが難しい。つまり、特許文献１に開示されるプラズマ発生装置によって、上記問題を解決することはできない。 As a plasma generator using a quartz tube having a shape different from the above, a plasma generator including a quartz tube formed by bonding inexpensive quartz plates and a coil wound around the quartz tube is conceivable. As an example of such a plasma generator, there is a plasma generator disclosed in Patent Document 1. As shown in FIG. 21, when the thermal plasma 1208 is generated by the plasma generator disclosed in Patent Document 1, the thermal plasma 1208 has a shape surrounding the central axis of the coil. At this time, if the high-temperature thermal plasma contacts the flat portion of the quartz tube 1201a, the quartz tube may be damaged. Therefore, also in the plasma generator disclosed in Patent Document 1, it is difficult to stably maintain the thermal plasma generated in the interior, as in the conventional plasma generator. That is, the above problem cannot be solved by the plasma generator disclosed in Patent Document 1.
　本発明は、上記問題を解決するためになされたものであり、熱プラズマを安定的に発生させることができるプラズマ発生装置等を提供することを課題とする。 The present invention has been made to solve the above problems, and an object of the present invention is to provide a plasma generator and the like capable of stably generating thermal plasma.
　上記課題を解決するために、本発明の一様態に係るプラズマ発生装置は、扁平形状のチャンバであって、当該チャンバの内部に所定方向にプラズマガスが流通するチャンバと、前記チャンバに対して前記所定方向に直交する方向に交播磁界を印加することにより、前記チャンバの内部に熱プラズマを発生させる磁界印加部とを備える。 In order to solve the above-described problem, a plasma generator according to one embodiment of the present invention is a flat chamber, a chamber in which plasma gas flows in a predetermined direction inside the chamber, and the chamber with respect to the chamber. A magnetic field application unit configured to generate thermal plasma in the chamber by applying a crossing magnetic field in a direction orthogonal to a predetermined direction;
　これによれば、円筒形状でない石英板から形成される石英管のような扁平形状のチャンバを用い、当該チャンバの内部に熱プラズマを発生させることができる。また、本プラズマ発生装置によれば、扁平形状のチャンバにおける厚さ方向に直交する方向（扁平方向）に広がる熱プラズマを発生させることができる。そのため、扁平方向に十分な大きさのチャンバとすることで、石英管の平面部分に熱プラズマが接触することを防ぐことができる。よって、当該プラズマ発生装置は、熱プラズマを安定的に発生させることができる。 According to this, it is possible to generate a thermal plasma inside the chamber using a flat chamber such as a quartz tube formed from a quartz plate which is not cylindrical. Moreover, according to this plasma generator, the thermal plasma which spreads in the direction (flat direction) orthogonal to the thickness direction in a flat chamber can be generated. Therefore, by setting the chamber sufficiently large in the flat direction, it is possible to prevent thermal plasma from contacting the flat portion of the quartz tube. Therefore, the plasma generator can stably generate thermal plasma.
　また、前記磁界印加部は、前記チャンバに対して前記所定方向に直交する方向に交播磁界を印加するコイルを有するとしてもよい。 Further, the magnetic field application unit may include a coil that applies a cross-seeding magnetic field in a direction orthogonal to the predetermined direction with respect to the chamber.
　これによれば、コイルによりチャンバに磁界を発生させることで、当該チャンバの内部に熱プラズマを発生させることができる。 According to this, by generating a magnetic field in the chamber by the coil, thermal plasma can be generated inside the chamber.
　また、前記磁界印加部は、さらに、端部が前記チャンバの近傍に配置される磁性体コアを有し、前記コイルは、前記磁性体コアの一部に巻回されるとしてもよい。 The magnetic field application unit may further include a magnetic core whose end is disposed in the vicinity of the chamber, and the coil may be wound around a part of the magnetic core.
　これによれば、チャンバがコイルから離れた位置に配置される場合において、コイルの内部に発生する磁界を磁性体コア（フェライトコア）によってチャンバの近傍へ伝えることができる。そして、フェライトコアによりチャンバの近傍に伝えられた磁界により、真空チャンバ内に熱プラズマを発生させることができる。よって、チャンバがコイルから離れた位置に配置される場合においても、当該プラズマ発生装置は、熱プラズマを安定的に発生させることができる。 According to this, when the chamber is arranged at a position away from the coil, the magnetic field generated in the coil can be transmitted to the vicinity of the chamber by the magnetic core (ferrite core). The thermal plasma can be generated in the vacuum chamber by the magnetic field transmitted to the vicinity of the chamber by the ferrite core. Therefore, even when the chamber is disposed at a position away from the coil, the plasma generator can stably generate thermal plasma.
　また、前記磁性体コアは、Ｕ字形状を有し、前記磁性体コアの両端部のそれぞれが、前記チャンバを厚さ方向から挟むように配置されるとしてもよい。 The magnetic core may have a U shape, and both end portions of the magnetic core may be disposed so as to sandwich the chamber from the thickness direction.
　これによれば、フェライトコアによりコイルの内部に発生する磁界をチャンバの近傍に伝えることで、チャンバの厚さ方向に一様な磁界を集中して発生させることができる。その結果、チャンバの厚さ方向の広い範囲に熱プラズマを安定的に発生させることができる。 According to this, a uniform magnetic field can be generated in a concentrated manner in the thickness direction of the chamber by transmitting the magnetic field generated in the coil by the ferrite core to the vicinity of the chamber. As a result, thermal plasma can be stably generated over a wide range in the thickness direction of the chamber.
　また、前記磁性体コアは、前記コイルが巻回された部分の断面積より、前記チャンバの近傍に配置される部分の断面積が小さい形状を有するとしてもよい。 Further, the magnetic core may have a shape in which a cross-sectional area of a portion disposed in the vicinity of the chamber is smaller than a cross-sectional area of a portion around which the coil is wound.
　これによれば、コイルの内部に発生する磁界をフェライトコアによりチャンバの近傍に伝え、さらに、フェライトコアの近傍において磁界を集中させることができる。つまり、電流の出力が小さい場合であってもチャンバ内に局所的に強い磁界を発生させることができる。よって、当該プラズマ発生装置は、比較的小さい電力によって熱プラズマを安定的に発生させることができる。 According to this, the magnetic field generated in the coil can be transmitted to the vicinity of the chamber by the ferrite core, and the magnetic field can be concentrated in the vicinity of the ferrite core. That is, a strong magnetic field can be generated locally in the chamber even when the current output is small. Therefore, the plasma generator can stably generate thermal plasma with relatively small electric power.
　また、前記磁界印加部は、前記チャンバを挟むように配置され、前記チャンバに対して前記所定方向に直交する方向に交播磁界を印加する複数のコイルを有するとしてもよい。 Further, the magnetic field application unit may include a plurality of coils that are arranged so as to sandwich the chamber and apply a cross-seeding magnetic field in a direction orthogonal to the predetermined direction with respect to the chamber.
　これによれば、２つのコイルにより、チャンバの厚さ方向に一様な磁界を集中して発生させることができる。その結果、チャンバの厚さ方向の広い範囲に熱プラズマを安定的に発生させることができる。 According to this, a uniform magnetic field can be concentrated and generated in the thickness direction of the chamber by the two coils. As a result, thermal plasma can be stably generated over a wide range in the thickness direction of the chamber.
　また、前記磁界印加部は、第一印加部及び第二印加部を有し、第一期間に前記第一印加部が前記チャンバに交播磁界を印加し、前記第一期間と異なる第二期間に前記第二印加部が前記チャンバに交播磁界を印加するとしてもよい。 The magnetic field application unit includes a first application unit and a second application unit, and the first application unit applies a cross-seed magnetic field to the chamber in a first period, and a second period different from the first period. The second application unit may apply a cross-seeding magnetic field to the chamber.
　これによれば、複数のコイルを用いて、チャンバの扁平方向の複数の箇所に、局所的に磁界を印加することができる。ここで、複数のコイルのそれぞれには、期間を分けて、順次、高周波電流を印加するようにすることで、従来と同等の出力容量の電流源によって実現することができる。つまり、プラズマ発生装置は、高価な大出力容量の電流源を用いることなく、熱プラズマを発生させることができる。よって、当該プラズマ発生装置は、大面積の熱プラズマを安定的に発生させることができる。 According to this, a magnetic field can be locally applied to a plurality of locations in the flat direction of the chamber using a plurality of coils. Here, each of the plurality of coils can be realized by a current source having an output capacity equivalent to that of the prior art by sequentially applying a high-frequency current to each of the coils at different periods. That is, the plasma generator can generate thermal plasma without using an expensive current source having a large output capacity. Thus, the plasma generator can stably generate a large area of thermal plasma.
　また、前記磁界印加部は、前記交播磁界の周波数をｆとし、磁束密度をＢとするとき、ｆ×Ｂが３０００Ｔ／ｓ以上、６５００Ｔ／ｓ以下の範囲内である前記交播磁界を印加するとしてもよい。 The magnetic field application unit applies the cross-seeding magnetic field in which f × B is within a range of 3000 T / s to 6500 T / s, where f is the frequency of the cross-seeding magnetic field and B is the magnetic flux density. You may do that.
　これによれば、プラズマ発生装置は、蒸気の磁束密度及び周波数の交播磁界により熱プラズマを発生させることができる。 According to this, the plasma generator can generate the thermal plasma by the cross magnetic field of the magnetic flux density and the frequency of the vapor.
　また、本発明の一様態に係るプラズマ発生方法は、扁平形状のチャンバであって、当該チャンバの内部に所定方向にプラズマガスが流通するチャンバを設置する設置ステップと、前記チャンバに対して前記所定方向に直交する方向に交播磁界を印加することにより、前記チャンバの内部に熱プラズマを発生させる磁界印加ステップとを含む。 The plasma generation method according to one aspect of the present invention includes an installation step of installing a chamber having a flat shape, in which plasma gas flows in a predetermined direction, and the predetermined chamber with respect to the chamber. Applying a cross-seed magnetic field in a direction perpendicular to the direction to generate a thermal plasma in the chamber.
　これにより、上記プラズマ発生装置と同様の効果を奏する。 This produces the same effect as the plasma generator.
　本発明により、熱プラズマを安定的に発生させることができるプラズマ発生装置等を提供することができる。 According to the present invention, it is possible to provide a plasma generator and the like that can stably generate thermal plasma.
図１は、実施の形態１に係るプラズマ発生装置の斜視図である。FIG. 1 is a perspective view of the plasma generator according to the first embodiment. 図２は、実施の形態１に係るプラズマ発生装置の側面図である。FIG. 2 is a side view of the plasma generating apparatus according to the first embodiment. 図３は、実施の形態１に係るプラズマ発生装置の正面図である。FIG. 3 is a front view of the plasma generating apparatus according to the first embodiment. 図４は、実施の形態１に係るプラズマ発生装置の上部フランジの平面図である。FIG. 4 is a plan view of the upper flange of the plasma generating apparatus according to the first embodiment. 図５は、実施の形態１に係るプラズマ発生装置の下部フランジの平面図である。FIG. 5 is a plan view of the lower flange of the plasma generating apparatus according to the first embodiment. 図６は、実施の形態１に係るプラズマ発生装置の模式図である。FIG. 6 is a schematic diagram of the plasma generator according to the first embodiment. 図７は、実施の形態２に係るプラズマ発生装置の模式図である。FIG. 7 is a schematic diagram of the plasma generator according to the second embodiment. 図８Ａは、実施の形態２におけるプラズマ発生条件及びプラズマ発生中の物理量の一例である。FIG. 8A is an example of plasma generation conditions and physical quantities during plasma generation in the second exemplary embodiment. 図８Ｂは、実施の形態２におけるプラズマ発生条件及びプラズマ発生中の物理量の他の一例である。FIG. 8B shows another example of plasma generation conditions and physical quantities during plasma generation in the second exemplary embodiment. 図９は、実施の形態３に係るプラズマ発生装置の模式図である。FIG. 9 is a schematic diagram of the plasma generator according to the third embodiment. 図１０は、実施の形態４に係るプラズマ発生装置におけるプラズマ発生方法の一例である。FIG. 10 shows an example of a plasma generation method in the plasma generation apparatus according to the fourth embodiment. 図１１は、実施の形態５に係るプラズマ発生装置の斜視図である。FIG. 11 is a perspective view of the plasma generating apparatus according to the fifth embodiment. 図１２は、実施の形態５に係るプラズマ発生装置の側面図である。FIG. 12 is a side view of the plasma generating apparatus according to the fifth embodiment. 図１３は、実施の形態５に係るプラズマ発生装置の正面図である。FIG. 13 is a front view of the plasma generator according to the fifth embodiment. 図１４は、実施の形態５に係るプラズマ発生装置の模式図である。FIG. 14 is a schematic diagram of a plasma generator according to the fifth embodiment. 図１５は、実施の形態５に係るプラズマ発生装置のフェライトの仕様の一例である。FIG. 15 is an example of the ferrite specifications of the plasma generating apparatus according to the fifth embodiment. 図１６は、実施の形態５におけるプラズマ発生条件及びプラズマ発生中の物理量の一例である。FIG. 16 is an example of plasma generation conditions and physical quantities during plasma generation in the fifth embodiment. 図１７は、実施の形態６に係るプラズマ発生装置の模式図である。FIG. 17 is a schematic diagram of a plasma generator according to the sixth embodiment. 図１８は、実施の形態７に係るプラズマ発生装置の模式図である。FIG. 18 is a schematic diagram of a plasma generator according to the seventh embodiment. 図１９は、従来のプラズマ発生装置の説明図である。FIG. 19 is an explanatory diagram of a conventional plasma generator. 図２０は、従来のプラズマ発生装置の断面図の一例である。FIG. 20 is an example of a cross-sectional view of a conventional plasma generator. 図２１は、従来のプラズマ発生装置の断面図の他の一例である。FIG. 21 is another example of a cross-sectional view of a conventional plasma generator.
　なお、以下で説明する実施の形態は、いずれも本発明の好ましい一具体例を示すものである。以下の実施の形態で示される数値、形状、材料、構成要素、構成要素の配置位置及び接続形態、ステップ、ステップの順序などは、一例であり、本発明を限定する主旨ではない。また、以下の実施の形態における構成要素のうち、本発明の最上位概念を示す独立請求項に記載されていない構成要素については、より好ましい形態を構成する任意の構成要素として説明される。 Note that each of the embodiments described below shows a preferred specific example of the present invention. The numerical values, shapes, materials, constituent elements, arrangement positions and connecting forms of the constituent elements, steps, order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept of the present invention are described as optional constituent elements that constitute a more preferable embodiment.
　なお、同一の構成要素には同一の符号を付し、説明を省略する場合がある。 In addition, the same code | symbol is attached | subjected to the same component and description may be abbreviate | omitted.
　（実施の形態１）
　実施の形態１において、従来と異なる真空チャンバの形状と、当該真空チャンバ及びコイルの位置関係とにより、従来より安定的に熱プラズマを発生させることができるプラズマ発生装置の例を示す。 (Embodiment 1)
In the first embodiment, an example of a plasma generation apparatus capable of generating thermal plasma more stably than the conventional one by the shape of the vacuum chamber different from the conventional one and the positional relationship between the vacuum chamber and the coil will be described.
　図１は、実施の形態１に係るプラズマ発生装置の斜視図である。 FIG. 1 is a perspective view of the plasma generator according to the first embodiment.
　図１に示されるように、実施の形態１に係るプラズマ発生装置は、真空チャンバ１１と、コイル１２とを備える。なお、真空チャンバは、単に「チャンバ」ともよぶ。 As shown in FIG. 1, the plasma generator according to Embodiment 1 includes a vacuum chamber 11 and a coil 12. The vacuum chamber is also simply referred to as “chamber”.
　真空チャンバ１１は、扁平形状の石英管１０（以降、単に石英管ともいう）と、上部フランジ１３と、下部フランジ１４とを備える。真空チャンバ１１は真空ポンプ（不図示）などと接続され、内部を真空にすることができる。真空チャンバ１１の内部にはプラズマガスが導入され、所定の物理条件が整うと熱プラズマが発生する。真空チャンバ１１を水冷容器（不図示）内に配置することにより、真空チャンバ１１をほぼ３００Ｋ（ケルビン）に保つ。石英管１０の寸法は、例えば、幅（ｙ方向）１２０ｍｍ、奥行き（ｘ方向）２０ｍｍ、高さ（ｚ方向）１００ｍｍである。この場合、扁平形状の厚さ方向とは、ｘ方向のことである。石英管１０の厚さは、例えば、５ｍｍである。ここでプラズマガスとは、熱プラズマのガス成分のことであり、例えば、Ａｒ（主成分）、ＣＨ４及びＨ２の混合ガスである。 The vacuum chamber 11 includes a flat quartz tube 10 (hereinafter also simply referred to as a quartz tube), an upper flange 13, and a lower flange 14. The vacuum chamber 11 is connected to a vacuum pump (not shown) or the like, and the inside can be evacuated. Plasma gas is introduced into the vacuum chamber 11, and thermal plasma is generated when predetermined physical conditions are met. By placing the vacuum chamber 11 in a water-cooled container (not shown), the vacuum chamber 11 is kept at approximately 300 K (Kelvin). The dimensions of the quartz tube 10 are, for example, a width (y direction) of 120 mm, a depth (x direction) of 20 mm, and a height (z direction) of 100 mm. In this case, the thickness direction of the flat shape is the x direction. The thickness of the quartz tube 10 is, for example, 5 mm. Here, the plasma gas is a gas component of thermal plasma, for example, a mixed gas of Ar (main component), CH 4 and H 2 .
　コイル１２は、真空チャンバの厚さ方向に隣接する位置に配置される。コイル１２は、電流源として動作するインバータ回路（不図示）に接続され、一定振幅の数百ｋＨｚの高周波電流を印加される。コイル１２は、コイル１２に流れる高周波電流により真空チャンバ１１の内部に交播磁界（以降、単に磁界ともよぶ）を発生させることで、真空チャンバ１１の内部に熱プラズマを発生させる。熱プラズマは、このような高周波の電界の変化に追随できず、あたかも導電性金属柱のような振る舞いをする。つまり、電磁誘導作用によりプラズマに円周方向に渦電流が流れ、この電流によって生ずるジュール熱によって熱プラズマが発生する。コイル１２は、交播磁界の周波数をｆとし、磁束密度をＢとするとき、ｆ×Ｂが３０００Ｔ／ｓ以上、６５００Ｔ／ｓ以下の範囲内である交播磁界を印加する。このような交播磁界は、例えば、周波数ｆを５０ｋＨｚ～５００ｋＨｚとし、磁束密度Ｂを１３ｍＴ～１３０ｍＴとすることにより実現される。なお、図１におけるコイル１２は、５ターン程度の巻き数で円筒形状となっているが、巻き数及び形状はこれに限られない。巻き数は、１ターン以上の任意のターン数であってよい。また、形状は、パンケーキ形状（渦巻き形状）、のこぎり形状、星形状、多角形形状、楕円形状、ミアンダ形状、または、それらの形状の特徴を有する形状などの任意の形状であってよい。なお、コイル１２は、磁界印加部に相当する。 The coil 12 is disposed at a position adjacent to the vacuum chamber in the thickness direction. The coil 12 is connected to an inverter circuit (not shown) that operates as a current source, and is applied with a high-frequency current having a constant amplitude of several hundred kHz. The coil 12 generates a thermal plasma in the vacuum chamber 11 by generating a crossing magnetic field (hereinafter also simply referred to as a magnetic field) in the vacuum chamber 11 by a high-frequency current flowing in the coil 12. Thermal plasma cannot follow such a high-frequency electric field change and behaves like a conductive metal column. That is, an eddy current flows in the plasma in the circumferential direction due to electromagnetic induction, and thermal plasma is generated by Joule heat generated by this current. The coil 12 applies a crossing magnetic field in which f × B is within a range of 3000 T / s or more and 6500 T / s or less when the frequency of the crossing magnetic field is f and the magnetic flux density is B. Such a cross-seeding magnetic field is realized, for example, by setting the frequency f to 50 kHz to 500 kHz and the magnetic flux density B to 13 mT to 130 mT. In addition, although the coil 12 in FIG. 1 has a cylindrical shape with a number of turns of about 5 turns, the number of turns and the shape are not limited thereto. The number of turns may be any number of turns greater than one. The shape may be any shape such as a pancake shape (swirl shape), a saw shape, a star shape, a polygonal shape, an elliptical shape, a meander shape, or a shape having characteristics of those shapes. The coil 12 corresponds to a magnetic field application unit.
　図２は、実施の形態１に係るプラズマ発生装置の側面図である。図２に示される構成要素は、図１に示される構成要素と同じであるため、同一の符号を付し、説明を省略する。 FIG. 2 is a side view of the plasma generator according to the first embodiment. The constituent elements shown in FIG. 2 are the same as the constituent elements shown in FIG.
　図３は、実施の形態１に係るプラズマ発生装置の正面図である。図３に示される構成要素は、図１に示される構成要素と同じであるため、同一の符号を付し、説明を省略する。 FIG. 3 is a front view of the plasma generator according to the first embodiment. The constituent elements shown in FIG. 3 are the same as the constituent elements shown in FIG.
　図４は、実施の形態１に係るプラズマ発生装置の上部フランジ１３の平面図である。 FIG. 4 is a plan view of the upper flange 13 of the plasma generator according to the first embodiment.
　図４に示されるように、上部フランジ１３には、プラズマガスをシース状に石英管１０の内壁面へ流せるように直径１ｍｍ程度のガス穴１３ｂを短辺に４個、長辺に３２個の計３６個有する。また、ガス穴１３ｂへプラズマガスを供給するためのガス経路１３ａを有する。石英管１０が、破線１３ｃで示される位置に配置される。 As shown in FIG. 4, the upper flange 13 has four gas holes 13b having a diameter of about 1 mm on the short side and 32 pieces on the long side so that the plasma gas can flow in a sheath shape to the inner wall surface of the quartz tube 10. 36 in total. Moreover, it has the gas path | route 13a for supplying plasma gas to the gas hole 13b. The quartz tube 10 is disposed at a position indicated by a broken line 13c.
　図５は、実施の形態１に係るプラズマ発生装置の下部フランジ１４の平面図である。 FIG. 5 is a plan view of the lower flange 14 of the plasma generator according to the first embodiment.
　図５に示されるように、下部フランジ１４は、真空ポンプ（不図示）などと接続され、真空チャンバ１１内部を真空にするための開口部１４ｈを有する。石英管１０が、１４ｃで示される位置に配置される。 As shown in FIG. 5, the lower flange 14 is connected to a vacuum pump (not shown) or the like, and has an opening 14h for evacuating the inside of the vacuum chamber 11. The quartz tube 10 is disposed at a position indicated by 14c.
　図６は、実施の形態１に係るプラズマ発生装置１の模式図である。 FIG. 6 is a schematic diagram of the plasma generator 1 according to the first embodiment.
　図６に示される真空チャンバ１１と、コイル１２とは、図１に示されるものと同一である。詳細な構成は省略する。 The vacuum chamber 11 and the coil 12 shown in FIG. 6 are the same as those shown in FIG. Detailed configuration is omitted.
　図６に示されるように、電流源がコイル１２に高周波電流１７を流すことで、真空チャンバ１１内部にｘ方向に高周波の磁界が印加される。この磁界により、この磁界を取り巻くような形状の熱プラズマ１８が発生する。その際、熱プラズマ１８は、真空チャンバ１１内において、コイル１２により印加された磁界がより強い位置であるコイル１２に近い位置に発生する。 As shown in FIG. 6, a high-frequency magnetic field is applied to the inside of the vacuum chamber 11 in the x direction by causing the high-frequency current 17 to flow through the coil 12 from the current source. This magnetic field generates a thermal plasma 18 having a shape surrounding the magnetic field. At that time, the thermal plasma 18 is generated in the vacuum chamber 11 at a position close to the coil 12 where the magnetic field applied by the coil 12 is stronger.
　このような構成をとることで、真空チャンバ１１の内部に安定的に熱プラズマを発生することができる。その理由は以下のように説明される。第一に、熱プラズマと真空チャンバとの形状及び位置関係により、熱プラズマと真空チャンバ１１の内壁面との間に十分な空間があるからである。つまり、熱プラズマが、コイルにより印加される磁界を取り巻くような形状になるように（ｙ方向またはｚ方向に）膨らんだとしても、真空チャンバ１１の壁面までの間に十分な空間があるからである。第二に、真空チャンバの内壁面に沿うように（シース状に）流れるプラズマガスがあることで、熱プラズマが真空チャンバの内壁面に接触しにくいからである。なお、本実施の形態に係るプラズマ発生装置の構成に類似する、低圧のプラズマを発生させるプラズマ発生装置は知られているが、本実施の形態に係るプラズマ発生装置は高温及び高圧の熱プラズマを発生させるプラズマ発生装置として新規である。 By adopting such a configuration, it is possible to stably generate thermal plasma inside the vacuum chamber 11. The reason is explained as follows. First, there is a sufficient space between the thermal plasma and the inner wall surface of the vacuum chamber 11 due to the shape and positional relationship between the thermal plasma and the vacuum chamber. That is, even if the thermal plasma swells (in the y direction or the z direction) so as to surround the magnetic field applied by the coil, there is sufficient space between the vacuum chamber 11 and the wall surface. is there. Second, because there is a plasma gas flowing along the inner wall surface of the vacuum chamber (in the form of a sheath), thermal plasma is unlikely to contact the inner wall surface of the vacuum chamber. A plasma generator that generates low-pressure plasma similar to the configuration of the plasma generator according to this embodiment is known, but the plasma generator according to this embodiment generates high-temperature and high-pressure thermal plasma. It is novel as a plasma generator to be generated.
　以上のように、本発明の一態様に係るプラズマ発生装置によれば、円筒形状でない石英板から形成される石英管のような扁平形状の真空チャンバを用い、当該真空チャンバの内部に熱プラズマを発生させることができる。また、本プラズマ発生装置によれば、扁平形状の真空チャンバにおける厚さ方向に直交する方向（扁平方向）に広がる熱プラズマを発生させることができる。そのため、扁平方向に十分な大きさの真空チャンバとすることで、石英管の平面部分に熱プラズマが接触することを防ぐことができる。よって、当該プラズマ発生装置は、熱プラズマを安定的に発生させることができる。 As described above, according to the plasma generator of one embodiment of the present invention, a flat vacuum chamber such as a quartz tube formed from a non-cylindrical quartz plate is used, and thermal plasma is generated inside the vacuum chamber. Can be generated. Moreover, according to this plasma generator, the thermal plasma which spreads in the direction (flat direction) orthogonal to the thickness direction in a flat vacuum chamber can be generated. Therefore, by making the vacuum chamber sufficiently large in the flat direction, it is possible to prevent thermal plasma from contacting the flat portion of the quartz tube. Therefore, the plasma generator can stably generate thermal plasma.
　これによれば、コイルによりチャンバに磁界を発生させることで、当該チャンバの内部に熱プラズマを発生させることができる。 According to this, by generating a magnetic field in the chamber by the coil, thermal plasma can be generated inside the chamber.
　（実施の形態２）
　実施の形態２において、真空チャンバを挟むようにコイルを配置することで、実施の形態１より安定的に熱プラズマを発生させることができるプラズマ発生装置の例を示す。 (Embodiment 2)
In Embodiment 2, an example of a plasma generator that can generate thermal plasma more stably than Embodiment 1 by arranging coils so as to sandwich a vacuum chamber is shown.
　図７は、実施の形態２に係るプラズマ発生装置２ａ及び２ｂの模式図である。 FIG. 7 is a schematic diagram of plasma generators 2a and 2b according to the second embodiment.
　図７の（ａ）に示されるように、実施の形態２に係るプラズマ発生装置２ａは、真空チャンバ２１と、コイル２２ａと、コイル２２ｂとを備える。 As shown in FIG. 7A, the plasma generator 2a according to Embodiment 2 includes a vacuum chamber 21, a coil 22a, and a coil 22b.
　真空チャンバ２１は、真空チャンバ１１と同じものであってよい。コイル２２ａには高周波電流２７ａが印加される。また、コイル２２ｂには高周波電流２７ａが印加される。高周波電流２７ａと高周波電流２７とは、周期及び位相が等しくなるように制御される。 The vacuum chamber 21 may be the same as the vacuum chamber 11. A high frequency current 27a is applied to the coil 22a. A high frequency current 27a is applied to the coil 22b. The high-frequency current 27a and the high-frequency current 27 are controlled so that the period and phase are equal.
　なお、図７の（ｂ）に示されるように、コイル２２ａ及びコイル２２ｂが直列に接続され、単一の電流源から高周波電流２７を供給されるプラズマ発生装置２ｂとしてもよい。この場合、上記の高周波電流２７ａと高周波電流２７とが、周期及び位相だけでなく、振幅も等しくなるように制御された場合に相当する。以下では、コイル２２ａ及びコイル２２ｂが直列に接続され、単一の電流源から高周波電流２７を供給される場合について説明する。 Note that, as shown in FIG. 7B, a plasma generator 2b in which a coil 22a and a coil 22b are connected in series and a high-frequency current 27 is supplied from a single current source may be used. In this case, this corresponds to the case where the high-frequency current 27a and the high-frequency current 27 are controlled so as to have the same amplitude as well as the period and phase. Below, the case where the coil 22a and the coil 22b are connected in series and the high frequency current 27 is supplied from a single current source is demonstrated.
　図７の（ｂ）に示されるように、コイル２２ａ及びコイル２２ｂに高周波電流２７が印加されると、真空チャンバ２１内に熱プラズマ２８が発生する。高周波電流２７などの所定の物理条件については後述する。 As shown in FIG. 7B, when a high frequency current 27 is applied to the coil 22a and the coil 22b, a thermal plasma 28 is generated in the vacuum chamber 21. Predetermined physical conditions such as the high-frequency current 27 will be described later.
　このような構成をとることにより、真空チャンバ２１内にｘ方向の比較的強い磁界が発生するため、熱プラズマ２８は、実施の形態１における熱プラズマ１８よりｘ方向において広い範囲に発生する。よって、真空チャンバ２１の内部により安定的に熱プラズマを発生させることができる。 By adopting such a configuration, a relatively strong magnetic field in the x direction is generated in the vacuum chamber 21, so that the thermal plasma 28 is generated in a wider range in the x direction than the thermal plasma 18 in the first embodiment. Therefore, thermal plasma can be generated more stably in the vacuum chamber 21.
　図８Ａは、実施の形態２におけるプラズマ発生条件及びプラズマ発生中の物理量の一例である。 FIG. 8A is an example of plasma generation conditions and physical quantities during plasma generation in the second exemplary embodiment.
　図８Ａの（ａ）は、インバータ回路（電流源）に入力する直流電圧ＶＤＣ及び直流電流ＩＤＣの条件、インバータ回路（電流源）が出力する交流電流の周波数ｆ、有効電力Ｐ、並びに、真空チャンバ２１内の圧力及びガス流量を示す。図８Ａの（ｂ）～（ｅ）は、熱プラズマが発生しているときの電源応答及び温度の時間変化の一例である。具体的には、（ｂ）コイル２２ａ及びコイル２２ｂに印加される電圧Ｖｉｎｖ及び電流Ｉｉｎｖ、（ｃ）コイル２２ａ及びコイル２２ｂに印加される電圧の実効値Ｖｒｍｓ及び電流の実効値Ｉｒｍｓ、（ｄ）有効電力Ｐ、及び、（ｅ）温度［Ｋ］である。図８Ａに示されるように、本実施の形態に係るプラズマ発生装置は、６．８ｋＷの出力で６６００Ｋの熱プラズマを発生及び維持できることが確認される。 8A shows the conditions of the DC voltage VDC and the DC current IDC input to the inverter circuit (current source), the frequency f of the AC current output from the inverter circuit (current source), the active power P, and the vacuum chamber. The pressure in 21 and a gas flow rate are shown. (B) to (e) of FIG. 8A are examples of a power supply response and a temperature change with time when thermal plasma is generated. Specifically, (b) voltage Vinv and current Iinv applied to the coil 22a and coil 22b, (c) effective value Vrms and effective value Irms of current applied to the coil 22a and coil 22b, (d) Active power P and (e) temperature [K]. As shown in FIG. 8A, it is confirmed that the plasma generator according to the present embodiment can generate and maintain 6600 K thermal plasma with an output of 6.8 kW.
　なお、コイルに印加する高周波電流の振幅を２通り設定し、所定の条件でこれらの振幅を繰り返すことにより、被処理物に与えるダメージを抑制しながら高速に熱プラズマによる表面処理を行うことも可能である。より詳細には、コイルに第一の振幅を有する交流電流を流すことによって第一の磁界を熱プラズマに印加する第一印加ステップと、コイルに第一の振幅とは異なる第二の振幅を有する交流電流を流すことによって第二の磁界を熱プラズマに印加する第二印加ステップとを含み、熱プラズマ中に配置された被処理物の表面温度を所定範囲内に維持し、かつ、熱プラズマの発光スペクトルに含まれる第一の波長成分の強さが、当該第一印加ステップと、当該第二印加ステップとでは、所定値以上異なるように、当該第一印加ステップと当該第二印加ステップとが繰り返されるようにしてもよい。このようにすることで、被処理物の表面温度を、被処理物が熱的ダメージを受けない温度に維持される。また、熱プラズマ中の活性化学種（ラジカル）を増加させ、熱プラズマに印加される磁場の変化に同期して、効率よく表面処理を行うための２つの工程を交互に行うことができる。よって、被処理物に与える熱的ダメージを抑制するとともに、より高速に熱プラズマによる表面処理を行うことができる。このように発生させる熱プラズマの発生条件等について図８Ｂに示す。 In addition, by setting two kinds of amplitudes of the high-frequency current applied to the coil and repeating these amplitudes under predetermined conditions, it is possible to perform surface treatment with thermal plasma at a high speed while suppressing damage to the object to be processed. It is. More specifically, a first application step of applying a first magnetic field to the thermal plasma by flowing an alternating current having a first amplitude in the coil, and a second amplitude different from the first amplitude in the coil. A second application step of applying a second magnetic field to the thermal plasma by flowing an alternating current, maintaining the surface temperature of the workpiece disposed in the thermal plasma within a predetermined range, and The first application step and the second application step are such that the intensity of the first wavelength component included in the emission spectrum differs by a predetermined value or more between the first application step and the second application step. It may be repeated. By doing in this way, the surface temperature of a to-be-processed object is maintained at the temperature which a to-be-processed object does not receive a thermal damage. In addition, the active chemical species (radicals) in the thermal plasma can be increased, and two processes for efficiently performing the surface treatment can be performed alternately in synchronization with the change of the magnetic field applied to the thermal plasma. Therefore, thermal damage to the object to be processed can be suppressed, and surface treatment with thermal plasma can be performed at a higher speed. FIG. 8B shows the generation conditions of the thermal plasma generated in this way.
　図８Ｂは、実施の形態２におけるプラズマ発生条件及びプラズマ発生中の物理量の他の一例である。図８Ｂの（ａ）は、インバータ回路（電流源）に入力する直流電圧ＶＤＣ及び直流電流ＩＤＣの条件、インバータ回路（電流源）が出力する交流電流の周波数ｆ、有効電力Ｐ、真空チャンバ２１内のガス流量、高周波電流の変調信号、並びに、変調信号周波数を示す。ここで、変調信号におけるＳＣＬ（Shimmer Current Level）とは、２通り設定された高周波電流の振幅の一方に対する他方の比率である。また、変調信号におけるＤＦ（Duty factor）とは、変調周期に対する振幅が大きい電流を印加する時間の割合である。図８Ｂの（ｂ）～（ｆ）は、熱プラズマが発生しているときの電源応答及び温度の時間変化の一例である。具体的には、（ｂ）変調信号電圧、（ｃ）コイル２２ａ及びコイル２２ｂに印加される電圧Ｖｉｎｖ及び電流Ｉｉｎｖ、（ｄ）コイル２２ａ及びコイル２２ｂに印加される電圧の実効値Ｖｒｍｓ及び電流の実効値Ｉｒｍｓ、（ｅ）有効電力Ｐ、及び、（ｆ）真空チャンバ内の３箇所（（１）、（２）及び（３））の温度［Ｋ］である。図８Ｂに示されるように、本実施の形態に係るプラズマ発生装置は、２通りの振幅の高周波電流を切り替えながらコイルに印加することにより、８．９ｋＷの出力でおよそ９０００Ｋの熱プラズマを発生及び維持できることが確認される。 FIG. 8B shows another example of plasma generation conditions and physical quantities during plasma generation in the second exemplary embodiment. 8A shows the conditions of the DC voltage VDC and the DC current IDC input to the inverter circuit (current source), the frequency f of the AC current output from the inverter circuit (current source), the active power P, and the inside of the vacuum chamber 21. FIG. Gas flow rate, modulation signal of high-frequency current, and modulation signal frequency. Here, SCL (Shimmer Current Level) in the modulation signal is a ratio of the amplitude of one of the two set high frequency currents to the other. Further, DF (Duty factor) in the modulation signal is a ratio of time during which a current having a large amplitude with respect to the modulation period is applied. (B) to (f) of FIG. 8B are examples of a power supply response and a temperature change with time when thermal plasma is generated. Specifically, (b) the modulation signal voltage, (c) the voltage Vinv and current Iinv applied to the coil 22a and the coil 22b, (d) the effective value Vrms and current of the voltage applied to the coil 22a and the coil 22b. RMS value Irms, (e) active power P, and (f) temperature [K] at three locations ((1), (2) and (3)) in the vacuum chamber. As shown in FIG. 8B, the plasma generator according to the present embodiment generates a thermal plasma of approximately 9000 K with an output of 8.9 kW by applying a high-frequency current having two amplitudes to the coil while switching. It is confirmed that it can be maintained.
　以上のように、本発明の一態様に係るプラズマ発生装置によれば、２つのコイルにより、真空チャンバの厚さ方向に一様な磁界を集中して発生させることができる。その結果、真空チャンバの厚さ方向の広い範囲に熱プラズマを安定的に発生させることができる。 As described above, according to the plasma generator of one embodiment of the present invention, a uniform magnetic field can be generated in a concentrated manner in the thickness direction of the vacuum chamber by two coils. As a result, thermal plasma can be stably generated over a wide range in the thickness direction of the vacuum chamber.
　（実施の形態３）
　実施の形態３において、真空チャンバに隣接する複数の箇所にコイルを配置することで、実施の形態１より広い空間に熱プラズマを発生させることができるプラズマ発生装置の例を示す。 (Embodiment 3)
In Embodiment 3, an example of a plasma generator capable of generating thermal plasma in a wider space than Embodiment 1 by arranging coils at a plurality of locations adjacent to the vacuum chamber will be described.
　図９は、実施の形態２に係るプラズマ発生装置３の模式図である。 FIG. 9 is a schematic diagram of the plasma generator 3 according to the second embodiment.
　図９に示されるように、実施の形態２に係るプラズマ発生装置３は、真空チャンバ３１と、コイル３２ａと、コイル３２ｂと、コイル３２ｃとを備える。真空チャンバ３１は、真空チャンバ１１よりｚ方向に幅広な形状である。なお、真空チャンバ３１は、真空チャンバ１１よりｙ方向に幅広な形状であってもよい。 As shown in FIG. 9, the plasma generator 3 according to Embodiment 2 includes a vacuum chamber 31, a coil 32a, a coil 32b, and a coil 32c. The vacuum chamber 31 is wider than the vacuum chamber 11 in the z direction. The vacuum chamber 31 may have a shape wider than the vacuum chamber 11 in the y direction.
　コイル３２ａには高周波電流３７ａが印加される。また、コイル３２ｂには高周波電流３７ａが印加される。また、コイル３２ｃには高周波電流３７ｃが印加される。高周波電流３７ａと高周波電流３７ｂと高周波電流３７ｃとは、周期及び位相が等しくなるように制御される。 The high frequency current 37a is applied to the coil 32a. A high frequency current 37a is applied to the coil 32b. A high frequency current 37c is applied to the coil 32c. The high-frequency current 37a, the high-frequency current 37b, and the high-frequency current 37c are controlled so that the period and phase are equal.
　なお、コイル３２ａ、コイル３２ｂ及びコイル３２ｃが、直列に接続され、単一の電流源から高周波電流３７を供給されるようにしてもよい。この場合、上記の高周波電流３７ａと高周波電流３７ｂと高周波電流３７ｃとが、周期及び位相だけでなく、振幅も等しくなるように制御された場合に相当する。以下では、コイル３２ａ、コイル３２ｂ及びコイル３２ｃが直列に接続され、単一の電流源から高周波電流３７を供給される場合について説明する。 In addition, the coil 32a, the coil 32b, and the coil 32c may be connected in series, and the high frequency current 37 may be supplied from a single current source. In this case, this corresponds to the case where the high-frequency current 37a, the high-frequency current 37b, and the high-frequency current 37c are controlled to have the same amplitude as well as the period and phase. Below, the case where the coil 32a, the coil 32b, and the coil 32c are connected in series and the high frequency current 37 is supplied from a single current source is demonstrated.
　図９に示されるように、コイル３２ａ、コイル３２ｂ及びコイル３２ｃに高周波電流３７が印加されると、真空チャンバ３１内に熱プラズマ３８が発生する。 As shown in FIG. 9, when a high frequency current 37 is applied to the coil 32 a, the coil 32 b, and the coil 32 c, a thermal plasma 38 is generated in the vacuum chamber 31.
　ここで、従来のプラズマ発生装置との比較しながら、本実施の形態のプラズマ発生装置の特徴を説明する。従来のプラズマ発生装置において、大型の真空チャンバ及びコイルを用いたとしても、本実施の形態のように広い面積に熱プラズマを発生させることは難しい。なぜなら、大型のコイルが発生させる磁界、および、磁界が発生させる電界が大型石英管内の広い空間に存在するため、磁界および電界の密度が低下し、熱プラズマを発生することができないためである。これに対し、本実施の形態のプラズマ発生装置では、真空チャンバ内の広い空間のうちの局所的な領域に電界および磁界を印加することで局所的に熱プラズマを発生させる。複数の箇所に、この局所的な熱プラズマを発生させることで、広範囲な熱プラズマを発生させることができる。このように、本実施の形態に係るプラズマ発生装置は、従来のプラズマ発生装置では実現できなかった処理面積の大面積化を実現し得る。 Here, the features of the plasma generator of this embodiment will be described while comparing with the conventional plasma generator. Even if a large vacuum chamber and coil are used in a conventional plasma generator, it is difficult to generate thermal plasma over a wide area as in this embodiment. This is because the magnetic field generated by the large coil and the electric field generated by the magnetic field are present in a wide space in the large quartz tube, so that the density of the magnetic field and electric field is reduced and thermal plasma cannot be generated. On the other hand, in the plasma generator of the present embodiment, thermal plasma is generated locally by applying an electric field and a magnetic field to a local region in a wide space in the vacuum chamber. By generating this local thermal plasma at a plurality of locations, a wide range of thermal plasma can be generated. As described above, the plasma generation apparatus according to the present embodiment can realize a large processing area that cannot be realized by the conventional plasma generation apparatus.
　このような構成をとることにより、真空チャンバ３１内において、ｚ方向（または、ｙ方向）の広い範囲において熱プラズマ３８を発生させることができる。このような広い範囲に渡る熱プラズマを利用すれば、広い表面積を有する試料に対して、熱プラズマを利用した表面処理を施すことが可能である。 By adopting such a configuration, the thermal plasma 38 can be generated in a wide range in the z direction (or y direction) in the vacuum chamber 31. If such a wide range of thermal plasma is used, it is possible to perform surface treatment using thermal plasma on a sample having a large surface area.
　なお、図９においてコイルの数を３として説明したが、コイルの数は２以上の任意の数であってよい。その場合、各コイルに対して同様の制御を行うことが可能である。その結果、真空チャンバ内のより広い空間に熱プラズマを発生させることができ、より広い表面積を有する試料に対する表面処理を施すことが可能となる。 In addition, although the number of coils was demonstrated in FIG. 9 as three, the number of coils may be arbitrary numbers 2 or more. In that case, the same control can be performed on each coil. As a result, thermal plasma can be generated in a wider space in the vacuum chamber, and surface treatment can be performed on a sample having a larger surface area.
　なお、本実施の形態において、真空チャンバ３１の長尺方向の寸法が比較的長い場合には、真空チャンバ３１の内部に、強度を維持するための支え棒又は仕切り板を挿入してもよい。これにより、真空チャンバ３１内外の温度差、圧力差、または、外力などにより真空チャンバ３１が破損することを未然に防ぐことができる。 In this embodiment, when the dimension of the vacuum chamber 31 in the longitudinal direction is relatively long, a support bar or a partition plate for maintaining the strength may be inserted into the vacuum chamber 31. Thereby, it is possible to prevent the vacuum chamber 31 from being damaged due to a temperature difference, pressure difference, external force, or the like inside and outside the vacuum chamber 31.
　なお、本実施の形態において、真空チャンバ１１より幅広な真空チャンバ３１を用いたが、真空チャンバ１１を複数並べて配置することで幅広な真空チャンバ（不図示）を形成することも可能である。幅広な真空チャンバでは、同等のサイズの真空チャンバ３１と比較して石英管の厚さを抑えることができる。具体的には、例えば、１０００ｍｍ×１００ｍｍ×２０ｍｍの石英管の真空チャンバ３１には、１０ｍｍ厚の石英管を用いる必要がある。それに対して、１００ｍｍ×１００ｍｍ×２０ｍｍの真空チャンバ１１を１０個並べて形成される１０００ｍｍ×１００ｍｍ×２０ｍｍの石英管を用いた幅広な真空チャンバに用いられる石英管は約３ｍｍ厚でよい。また、幅広な真空チャンバでは、同等のサイズの真空チャンバ３１と比較して、水冷が容易である。さらに、幅広な真空チャンバによれば、長尺方向の長さが数メートルを超える熱プラズマを発生させることも可能となる。 In this embodiment, the vacuum chamber 31 wider than the vacuum chamber 11 is used. However, it is possible to form a wide vacuum chamber (not shown) by arranging a plurality of vacuum chambers 11 side by side. In a wide vacuum chamber, the thickness of the quartz tube can be suppressed as compared with the vacuum chamber 31 of the same size. Specifically, for example, a 10 mm thick quartz tube needs to be used for the vacuum chamber 31 of a quartz tube of 1000 mm × 100 mm × 20 mm. On the other hand, a quartz tube used in a wide vacuum chamber using a 1000 mm × 100 mm × 20 mm quartz tube formed by arranging 10 100 mm × 100 mm × 20 mm vacuum chambers 11 may be about 3 mm thick. Moreover, in the wide vacuum chamber, compared with the vacuum chamber 31 of the same size, water cooling is easy. Further, the wide vacuum chamber can generate thermal plasma having a length in the longitudinal direction exceeding several meters.
　このような幅広な真空チャンバを有するプラズマ発生装置によっても、従来のプラズマ発生装置では実現できなかった処理面積の大面積化を実現し得る。 Even with a plasma generator having such a wide vacuum chamber, it is possible to realize a large processing area that could not be realized with a conventional plasma generator.
　以上のように、本発明の一態様に係るプラズマ発生装置によれば、複数のコイルを用いて、真空チャンバの扁平方向の複数の箇所に、局所的に磁界を印加することができる。ここで、複数のコイルのそれぞれには、期間を分けて、順次、高周波電流を印加するようにすることで、従来と同等の出力容量の電流源によって実現することができる。つまり、本プラズマ発生装置では、高価な大出力容量の電流源を用いることなく、熱プラズマを発生させることができる。よって、当該プラズマ発生装置は、大面積の熱プラズマを安定的に発生させることができる。 As described above, according to the plasma generator of one embodiment of the present invention, a magnetic field can be locally applied to a plurality of locations in the flat direction of the vacuum chamber using a plurality of coils. Here, each of the plurality of coils can be realized by a current source having an output capacity equivalent to that of the prior art by sequentially applying a high-frequency current to each of the coils at different periods. That is, in this plasma generator, thermal plasma can be generated without using an expensive current source with a large output capacity. Thus, the plasma generator can stably generate a large area of thermal plasma.
　（実施の形態４）
　実施の形態４において、真空チャンバに隣接する複数の箇所にコイルを配置し、その複数のコイルに対して順次電流を印加することで、従来と同等の出力容量のインバータ回路（電流源）を用いて実施の形態１のプラズマ発生装置１より広い面積に熱プラズマを発生させることができるプラズマ発生装置の例を示す。 (Embodiment 4)
In the fourth embodiment, an inverter circuit (current source) having an output capacity equivalent to the conventional one is used by arranging coils at a plurality of locations adjacent to the vacuum chamber and sequentially applying a current to the plurality of coils. An example of a plasma generator capable of generating thermal plasma over a larger area than the plasma generator 1 of the first embodiment will be described.
　図１０は、実施の形態３に係るプラズマ発生装置３におけるプラズマ発生方法の模式図である。 FIG. 10 is a schematic diagram of a plasma generation method in the plasma generation apparatus 3 according to the third embodiment.
　図１０に示されるプラズマ発生装置３は、実施の形態２で説明したものと同一である。コイル３２ａ、コイル３２ｂ及びコイル３２ｃに、それぞれ、高周波電流３７ａ、高周波電流３７ｂ及び高周波電流３７ｃが印加される。 The plasma generator 3 shown in FIG. 10 is the same as that described in the second embodiment. A high frequency current 37a, a high frequency current 37b, and a high frequency current 37c are applied to the coil 32a, the coil 32b, and the coil 32c, respectively.
　実施の形態３に係るプラズマ発生方法では、まず、図１０の（ａ）に示されるように、コイル３２ａに高周波電流３７ａが印加される。これにより、真空チャンバ３１内のコイル３２ａに近い位置に熱プラズマ３８ａが発生する。 In the plasma generation method according to the third embodiment, first, a high frequency current 37a is applied to the coil 32a as shown in FIG. Thereby, the thermal plasma 38a is generated at a position near the coil 32a in the vacuum chamber 31.
　次に、図１０の（ｂ）に示されるように、コイル３２ｂに高周波電流３７ｂが印加される。これにより、真空チャンバ３１内のコイル３２ｂに近い位置に熱プラズマ３８ｂが発生する。 Next, as shown in FIG. 10B, a high frequency current 37b is applied to the coil 32b. Thereby, the thermal plasma 38b is generated at a position near the coil 32b in the vacuum chamber 31.
　次に、図１０の（ｃ）に示されるように、コイル３２ｃに高周波電流３７ｃが印加される。これにより、真空チャンバ３１内のコイル３２ｃに近い位置に熱プラズマ３８ｃが発生する。 Next, as shown in FIG. 10 (c), a high frequency current 37c is applied to the coil 32c. Thereby, the thermal plasma 38c is generated at a position near the coil 32c in the vacuum chamber 31.
　次に、図１０の（ａ）に戻り、上記と同様の方法を実行する。 Next, returning to FIG. 10A, the same method as described above is executed.
　以上により、真空チャンバ３１の中の複数の部分に順次、熱プラズマを発生させることができる。 As described above, thermal plasma can be sequentially generated in a plurality of portions in the vacuum chamber 31.
　なお、実施の形態３と同様、コイルの数は２以上の任意の数であってよい。 Note that, as in the third embodiment, the number of coils may be an arbitrary number of two or more.
　このようにすることで、実施の形態１のプラズマ発生装置１と同等の出力容量のインバータ回路（電流源）を用いて、真空チャンバ内の広い空間に熱プラズマを発生させることができ、より広い表面積を有する試料に対する表面処理を施すことが可能となる。 By doing so, it is possible to generate thermal plasma in a wide space in the vacuum chamber using an inverter circuit (current source) having an output capacity equivalent to that of the plasma generator 1 of the first embodiment. It is possible to perform a surface treatment on a sample having a surface area.
　（実施の形態５）
　実施の形態５において、コイルと真空チャンバとを離れた位置に配置する場合に、コイルが発生させる磁界を真空チャンバ内に伝え、真空チャンバ内に熱プラズマを発生させることができるプラズマ発生装置の例を示す。 (Embodiment 5)
In Embodiment 5, when a coil and a vacuum chamber are arranged at positions separated from each other, an example of a plasma generating apparatus capable of transmitting a magnetic field generated by a coil into the vacuum chamber and generating thermal plasma in the vacuum chamber Indicates.
　図１１は、実施の形態４に係るプラズマ発生装置４の模式図である。 FIG. 11 is a schematic diagram of the plasma generator 4 according to the fourth embodiment.
　図１１に示されるプラズマ発生装置４は、真空チャンバ４１と、コイル４２と、フェライトコア４５を備える。真空チャンバ４１とコイル４２とは、それぞれ、実施の形態１における真空チャンバ１１とコイル１２と同等のものである。 The plasma generator 4 shown in FIG. 11 includes a vacuum chamber 41, a coil 42, and a ferrite core 45. The vacuum chamber 41 and the coil 42 are equivalent to the vacuum chamber 11 and the coil 12 in the first embodiment, respectively.
　フェライトコア４５は、Ｕ字形状であり、その両端部が真空チャンバ４１の近傍に配置される。また、フェライトコア４５の一部にコイル４２が巻回される。このように構成することで、コイル４２が発生させる磁界を真空チャンバ４１の近傍へ伝えることができる。なお、Ｕ字形状のフェライトコアの両端部のそれぞれが真空チャンバ４１の両側面のそれぞれの近傍に配置されている構成の他、フェライトコアの一方の端部だけが、真空チャンバ４１の近傍に配置される構成も本発明の技術的範囲に含まれる。また、フェライトコア４５は、Ｕ字形状でなくてもよく、直線形状、曲線形状、又は、それらを組み合わせた任意の形状であってもよい。フェライトコア４５は、磁性体コアの一例である。なお、フェライトコア４５は、一例として、強磁性酸化物のソフトフェライトで実現される。ソフトフェライトの仕様の一例を図１５に示す。 The ferrite core 45 is U-shaped, and both ends thereof are arranged in the vicinity of the vacuum chamber 41. The coil 42 is wound around a part of the ferrite core 45. With this configuration, the magnetic field generated by the coil 42 can be transmitted to the vicinity of the vacuum chamber 41. In addition to the configuration in which both ends of the U-shaped ferrite core are disposed in the vicinity of both side surfaces of the vacuum chamber 41, only one end of the ferrite core is disposed in the vicinity of the vacuum chamber 41. Such a configuration is also included in the technical scope of the present invention. Moreover, the ferrite core 45 does not need to be U-shaped, and may be a linear shape, a curved shape, or an arbitrary shape combining them. The ferrite core 45 is an example of a magnetic core. In addition, the ferrite core 45 is implement | achieved by the soft ferrite of a ferromagnetic oxide as an example. An example of the specification of soft ferrite is shown in FIG.
　図１２は、実施の形態５に係るプラズマ発生装置の側面図である。図１２に示される構成要素は、図１１に示される構成要素と同じであるため、同一の符号を付し、説明を省略する。 FIG. 12 is a side view of the plasma generator according to the fifth embodiment. The constituent elements shown in FIG. 12 are the same as the constituent elements shown in FIG.
　図１３は、実施の形態５に係るプラズマ発生装置の正面図である。図１３に示される構成要素は、図１１に示される構成要素と同じであるため、同一の符号を付し、説明を省略する。 FIG. 13 is a front view of the plasma generator according to the fifth embodiment. The constituent elements shown in FIG. 13 are the same as the constituent elements shown in FIG.
　図１４は、実施の形態５に係るプラズマ発生装置４の模式図である。 FIG. 14 is a schematic diagram of the plasma generator 4 according to the fifth embodiment.
　図１４に示される真空チャンバ４１と、コイル４２と、フェライトコア４５とは、図１１に示されるものと同一である。詳細な構成は省略する。 The vacuum chamber 41, the coil 42, and the ferrite core 45 shown in FIG. 14 are the same as those shown in FIG. Detailed configuration is omitted.
　図１５は、実施の形態５におけるプラズマ発生条件及びプラズマ発生中の物理量の一例である。 FIG. 15 is an example of plasma generation conditions and physical quantities during plasma generation in the fifth embodiment.
　図１５の（ａ）は、インバータ回路（電流源）に入力する直流電圧ＶＤＣ及び直流電流ＩＤＣの条件、インバータ回路（電流源）が出力する交流電流の周波数ｆ、有効電力Ｐ、真空チャンバ４１内の圧力及びガス流量を示す。図１５の（ｂ）～（ｅ）は、熱プラズマが発生しているときの電源応答及び温度の時間変化の一例である。具体的には、（ｂ）コイル４２に印加された電圧Ｖｉｎｖ及び電流Ｉｉｎｖ、（ｃ）コイル４２に印加された電圧の実効値Ｖｒｍｓ及び電流の実効値Ｉｒｍｓ、（ｄ）有効電力Ｐ、及び、（ｅ）温度［Ｋ］である。図１５に示されるように、本実施の形態に係るプラズマ発生装置は、１．９ｋＷの出力で５０００Ｋの熱プラズマを発生及び維持できることが確認される。 15A shows the conditions of the DC voltage VDC and the DC current IDC input to the inverter circuit (current source), the frequency f of the AC current output from the inverter circuit (current source), the effective power P, and the inside of the vacuum chamber 41. FIG. Pressure and gas flow rate are shown. (B) to (e) of FIG. 15 are examples of a power supply response and a temperature change with time when thermal plasma is generated. Specifically, (b) voltage Vinv and current Iinv applied to the coil 42, (c) effective value Vrms and effective value Irms of voltage applied to the coil 42, (d) active power P, and (E) Temperature [K]. As shown in FIG. 15, it is confirmed that the plasma generator according to the present embodiment can generate and maintain a thermal plasma of 5000K with an output of 1.9 kW.
　このように構成することにより、コイルと真空チャンバとが離れた位置に配置される場合にも、コイルが発生させる磁界をフェライトコアにより真空チャンバ内に伝えることができ、真空チャンバ内に熱プラズマを発生させることができる。よって、コイルを真空チャンバと離れた位置に配置する場合にも、真空チャンバ内に安定的に熱プラズマを発生させることができる。また、フェライトコアは廉価に入手することができ、また、容易に加工することができるので、本実施の形態に係るプラズマ発生装置の製造コストは、実施の形態１に係るプラズマ発生装置の製造コストと同等となる。すなわち、本実施の形態に係るプラズマ発生装置によれば、製造コストを大幅に増加させることなく、コイルを真空チャンバと離れた位置に配置することができる。 With this configuration, even when the coil and the vacuum chamber are arranged at a distance, the magnetic field generated by the coil can be transmitted to the vacuum chamber by the ferrite core, and thermal plasma is generated in the vacuum chamber. Can be generated. Therefore, even when the coil is disposed at a position away from the vacuum chamber, thermal plasma can be stably generated in the vacuum chamber. In addition, since the ferrite core can be obtained at a low price and can be easily processed, the manufacturing cost of the plasma generating apparatus according to the present embodiment is the manufacturing cost of the plasma generating apparatus according to the first embodiment. Is equivalent to That is, according to the plasma generator according to the present embodiment, the coil can be arranged at a position away from the vacuum chamber without significantly increasing the manufacturing cost.
　以上のように、本発明の一態様に係るプラズマ発生装置によれば、真空チャンバがコイルから離れた位置に配置される場合において、コイルの内部に発生する磁界をフェライトコアによって真空チャンバの近傍へ伝えることができる。そして、フェライトコアにより真空チャンバの近傍に伝えられた磁界により、真空チャンバ内に熱プラズマを発生させることができる。よって、真空チャンバがコイルから離れた位置に配置される場合においても、当該プラズマ発生装置は、熱プラズマを安定的に発生させることができる。 As described above, according to the plasma generator of one aspect of the present invention, when the vacuum chamber is disposed at a position away from the coil, the magnetic field generated inside the coil is moved to the vicinity of the vacuum chamber by the ferrite core. I can tell you. A thermal plasma can be generated in the vacuum chamber by the magnetic field transmitted to the vicinity of the vacuum chamber by the ferrite core. Therefore, even when the vacuum chamber is disposed at a position away from the coil, the plasma generator can stably generate thermal plasma.
　また、フェライトコアによりコイルの内部に発生する磁界を真空チャンバの近傍に伝えることで、真空チャンバの厚さ方向に一様な磁界を集中して発生させることができる。その結果、真空チャンバの厚さ方向の広い範囲に熱プラズマを安定的に発生させることができる。 Also, by transmitting the magnetic field generated inside the coil by the ferrite core to the vicinity of the vacuum chamber, a uniform magnetic field can be generated in a concentrated manner in the thickness direction of the vacuum chamber. As a result, thermal plasma can be stably generated over a wide range in the thickness direction of the vacuum chamber.
　（実施の形態６）
　実施の形態６において、コイルが発生させる磁界を集中させて真空チャンバ内に伝え、真空チャンバ内に熱プラズマを発生させることができるプラズマ発生装置の例を示す。 (Embodiment 6)
In Embodiment 6, an example of a plasma generator capable of concentrating a magnetic field generated by a coil and transmitting it to the vacuum chamber to generate thermal plasma in the vacuum chamber will be described.
　図１４は、実施の形態６に係るプラズマ発生装置５の模式図である。 FIG. 14 is a schematic diagram of the plasma generator 5 according to the sixth embodiment.
　図１４に示されるプラズマ発生装置５は、真空チャンバ５１と、コイル５２と、フェライトコア５５を備える。真空チャンバ５１とコイル５２とは、それぞれ、実施の形態１における真空チャンバ１１とコイル１２と同等のものである。 The plasma generator 5 shown in FIG. 14 includes a vacuum chamber 51, a coil 52, and a ferrite core 55. The vacuum chamber 51 and the coil 52 are equivalent to the vacuum chamber 11 and the coil 12 in the first embodiment, respectively.
　フェライトコア５５は、実施の形態５のフェライトコア４５と同様に端部が真空チャンバ５１の近傍に配置され、一部にコイル５２が巻回される。フェライトコア５５が、フェライトコア４５と異なる点は、真空チャンバ５１の近傍に配置される端部の断面積が、コイル５２が巻回される位置における断面積より小さい点である。つまり、フェライトコア５５は、コイルが巻回される位置よりも真空チャンバ５１の近傍の位置において細くなっている。 The ferrite core 55 is arranged in the vicinity of the vacuum chamber 51 in the same manner as the ferrite core 45 of the fifth embodiment, and a coil 52 is wound around a part thereof. The difference between the ferrite core 55 and the ferrite core 45 is that the cross-sectional area of the end disposed in the vicinity of the vacuum chamber 51 is smaller than the cross-sectional area at the position where the coil 52 is wound. That is, the ferrite core 55 is thinner at a position near the vacuum chamber 51 than a position where the coil is wound.
　このように構成することで、真空チャンバ５１の一部の領域に対して、実施の形態５のフェライトコア４５の場合よりも磁界を集中させて印加することができる。これにより、コイル５２に印加する高周波電流５７として、高周波電流４７と等しい高周波電流を印加した場合に、より強い磁界を真空チャンバに印加することができる。また、コイル５２により振幅の小さい高周波電流５７を印加することで熱プラズマを発生させることもできる。 With this configuration, it is possible to apply a more concentrated magnetic field to a partial region of the vacuum chamber 51 than in the case of the ferrite core 45 of the fifth embodiment. Thereby, when a high frequency current equal to the high frequency current 47 is applied as the high frequency current 57 applied to the coil 52, a stronger magnetic field can be applied to the vacuum chamber. Further, thermal plasma can be generated by applying a high-frequency current 57 having a small amplitude by the coil 52.
　以上のように、本発明の一態様に係るプラズマ発生装置によれば、コイルの内部に発生する磁界をフェライトコアにより真空チャンバの近傍に伝え、さらに、フェライトコアの近傍において磁界を集中させることができる。つまり、電流の出力が小さい場合であっても真空チャンバ内に局所的に強い磁界を発生させることができる。よって、当該プラズマ発生装置は、比較的小さい電力によって熱プラズマを安定的に発生させることができる。 As described above, according to the plasma generator of one embodiment of the present invention, the magnetic field generated in the coil is transmitted to the vicinity of the vacuum chamber by the ferrite core, and the magnetic field is concentrated in the vicinity of the ferrite core. it can. That is, a strong magnetic field can be locally generated in the vacuum chamber even when the output of current is small. Therefore, the plasma generator can stably generate thermal plasma with relatively small electric power.
　（実施の形態７）
　実施の形態７において、コイルが発生させる磁界を分散させて真空チャンバの複数の箇所に磁界を発生させ、真空チャンバ内の広い空間に熱プラズマを発生させることができるプラズマ発生装置の例を示す。 (Embodiment 7)
In Embodiment 7, an example of a plasma generator capable of generating a thermal plasma in a wide space in a vacuum chamber by dispersing a magnetic field generated by a coil to generate a magnetic field at a plurality of locations in the vacuum chamber will be described.
　実施の形態７に係るプラズマ発生装置の模式図である。 FIG. 9 is a schematic diagram of a plasma generator according to a seventh embodiment.
　図１５に示されるプラズマ発生装置６は、真空チャンバ６１と、コイル６２と、フェライトコア６５とを備える。真空チャンバ６１は、真空チャンバ１１よりｚ方向に幅広な形状である。なお、真空チャンバ６１は、真空チャンバ１１よりｙ方向に幅広な形状であってもよい。フェライトコア６５は、真空チャンバを挟むように互いに対向するように配置される３組（６個）の突起部（６５ａ、６５ｂ、６５ｃ、６５ｄ、６５ｅ及び６５ｆ）を有する。 The plasma generator 6 shown in FIG. 15 includes a vacuum chamber 61, a coil 62, and a ferrite core 65. The vacuum chamber 61 is wider than the vacuum chamber 11 in the z direction. The vacuum chamber 61 may have a shape wider than the vacuum chamber 11 in the y direction. The ferrite core 65 has three sets (six) of protrusions (65a, 65b, 65c, 65d, 65e, and 65f) that are arranged to face each other with the vacuum chamber interposed therebetween.
　このように構成することで、コイル６２が生じさせる磁界を、真空チャンバ６１の複数の箇所に集中させて印加することができる。その結果、真空チャンバ６１内において、ｚ方向の広い範囲において熱プラズマ６８を発生させることができる。 With this configuration, the magnetic field generated by the coil 62 can be applied to a plurality of locations in the vacuum chamber 61 in a concentrated manner. As a result, in the vacuum chamber 61, the thermal plasma 68 can be generated in a wide range in the z direction.
　なお、本実施の形態において、真空チャンバとして石英管を用いる例を示したが、真空チャンバの材料は石英管に限られない。石英管の他に、例えば、強度及び耐熱衝撃性のあるセラミック（例えば、Ｓｉ３Ｏ４）、アルミナを用いることも可能である。 In the present embodiment, an example in which a quartz tube is used as the vacuum chamber has been described, but the material of the vacuum chamber is not limited to the quartz tube. In addition to the quartz tube, for example, ceramic having strength and thermal shock resistance (for example, Si 3 O 4 ) or alumina can be used.
　以上、本発明のプラズマ発生装置について、実施の形態に基づいて説明したが、本発明は、この実施の形態に限定されるものではない。本発明の趣旨を逸脱しない限り、当業者が思いつく各種変形を本実施の形態に施したものや、異なる実施の形態における構成要素を組み合わせて構築される形態も、本発明の範囲内に含まれる。 As mentioned above, although the plasma generator of this invention was demonstrated based on embodiment, this invention is not limited to this embodiment. Unless it deviates from the meaning of this invention, the form which carried out the various deformation | transformation which those skilled in the art can think to this embodiment, and the structure constructed | assembled combining the component in different embodiment is also contained in the scope of the present invention. .
　本発明の一態様に係るプラズマ発生装置及びプラズマ発生方法は、表面改質処理または薄膜生成処理を含む表面処理などへ適用することが可能である。 The plasma generator and the plasma generation method according to one embodiment of the present invention can be applied to surface treatment including surface modification treatment or thin film production treatment.
　１、２ａ、２ｂ、３、４、５、６、１００１　　プラズマ発生装置
　１０、４０、１１０１ａ、１１０１ｂ、１２０１ａ、１２０１ｂ　　石英管
　１１、２１、３１、４１、５１、６１　　真空チャンバ
　１２、２２ａ、２２ｂ、３２ａ、３２ｂ、３２ｃ、４２、５２、６２、１１０２、１２０２　　コイル
　１３、４３　　上部フランジ
　１４、４４　　下部フランジ
　１７、２７、２７ａ、３７、３７ａ、３７ｂ、３７ｃ、４７、５７、６７、１１０７　　高周波電流
　１８、２８、３８、３８ａ、３８ｂ、３８ｃ、４８、５８、６８、１１０８、１２０８　　熱プラズマ
　４５、５５、６５　　フェライトコア
　６５ａ、６５ｂ、６５ｃ、６５ｄ、６５ｅ、６５ｆ　　突起部 1, 2a, 2b, 3, 4, 5, 6, 1001 Plasma generator 10, 40, 1101a, 1101b, 1201a, 1201b Quartz tube 11, 21, 31, 41, 51, 61 Vacuum chamber 12, 22a, 22b, 32a, 32b, 32c, 42, 52, 62, 1102, 1202 Coil 13, 43 Upper flange 14, 44 Lower flange 17, 27, 27a, 37, 37a, 37b, 37c, 47, 57, 67, 1107 High frequency current 18 28, 38, 38a, 38b, 38c, 48, 58, 68, 1108, 1208 Thermal plasma 45, 55, 65 Ferrite core 65a, 65b, 65c, 65d, 65e, 65f Protrusion

Claims (9)

  1. 　扁平形状のチャンバであって、当該チャンバの内部に所定方向にプラズマガスが流通するチャンバと、
    　前記チャンバに対して前記所定方向に直交する方向に交播磁界を印加することにより、前記チャンバの内部に熱プラズマを発生させる磁界印加部とを備える
    　プラズマ発生装置。     A flat chamber, in which a plasma gas flows in a predetermined direction inside the chamber;
    A plasma generating apparatus, comprising: a magnetic field applying unit configured to generate thermal plasma in the chamber by applying a crossing magnetic field in a direction orthogonal to the predetermined direction to the chamber.
  2. 　前記磁界印加部は、
    　前記チャンバに対して前記所定方向に直交する方向に交播磁界を印加するコイルを有する
    　請求項１に記載のプラズマ発生装置。     The magnetic field application unit is
    The plasma generator according to claim 1, further comprising a coil that applies a cross-seeding magnetic field to the chamber in a direction orthogonal to the predetermined direction.
  3. 　前記磁界印加部は、さらに、
    　端部が前記チャンバの近傍に配置される磁性体コアを有し、
    　前記コイルは、前記磁性体コアの一部に巻回される
    　請求項２に記載のプラズマ発生装置。     The magnetic field application unit further includes:
    An end portion having a magnetic core disposed in the vicinity of the chamber;
    The plasma generator according to claim 2, wherein the coil is wound around a part of the magnetic core.
  4. 　前記磁性体コアは、Ｕ字形状を有し、前記磁性体コアの両端部のそれぞれが、前記チャンバを厚さ方向から挟むように配置される
    　請求項３に記載のプラズマ発生装置。     The plasma generating apparatus according to claim 3, wherein the magnetic core has a U shape, and both end portions of the magnetic core are arranged so as to sandwich the chamber from the thickness direction.
  5. 　前記磁性体コアは、
    　前記コイルが巻回された部分の断面積より、前記チャンバの近傍に配置される部分の断面積が小さい形状を有する
    　請求項３または４に記載のプラズマ発生装置。     The magnetic core is
    5. The plasma generating apparatus according to claim 3, wherein a cross-sectional area of a portion disposed in the vicinity of the chamber is smaller than a cross-sectional area of a portion around which the coil is wound.
  6. 　前記磁界印加部は、
    　前記チャンバを挟むように配置され、前記チャンバに対して前記所定方向に直交する方向に交播磁界を印加する複数のコイルを有する
    　請求項１に記載のプラズマ発生装置。     The magnetic field application unit is
    The plasma generator according to claim 1, further comprising: a plurality of coils that are arranged so as to sandwich the chamber and apply a cross-seeding magnetic field in a direction orthogonal to the predetermined direction with respect to the chamber.
  7. 　前記磁界印加部は、
    　第一印加部及び第二印加部を有し、
    　第一期間に前記第一印加部が前記チャンバに交播磁界を印加し、前記第一期間と異なる第二期間に前記第二印加部が前記チャンバに交播磁界を印加する
    　請求項１に記載のプラズマ発生装置。     The magnetic field application unit is
    Having a first application part and a second application part,
    The first application unit applies a cross-seeding magnetic field to the chamber in a first period, and the second application unit applies a cross-seeding magnetic field to the chamber in a second period different from the first period. Plasma generator.
  8. 　前記磁界印加部は、
    　前記交播磁界の周波数をｆとし、磁束密度をＢとするとき、ｆ×Ｂが３０００Ｔ／ｓ以上、６５００Ｔ／ｓ以下の範囲内である前記交播磁界を印加する
    　請求項１～７のいずれか１項に記載のプラズマ発生装置。     The magnetic field application unit is
    The crossing magnetic field is applied such that f × B is within a range of 3000 T / s to 6500 T / s, where f is the frequency of the crossing magnetic field and B is the magnetic flux density. 2. The plasma generator according to claim 1.
  9. 　扁平形状のチャンバであって、当該チャンバの内部に所定方向にプラズマガスが流通するチャンバを設置する設置ステップと、
    　前記チャンバに対して前記所定方向に直交する方向に交播磁界を印加することにより、前記チャンバの内部に熱プラズマを発生させる磁界印加ステップとを含む
    　プラズマ発生方法。     An installation step of installing a chamber having a flat shape and a plasma gas flowing in a predetermined direction inside the chamber;
    A magnetic field applying step of generating a thermal plasma in the chamber by applying a crossing magnetic field in a direction orthogonal to the predetermined direction to the chamber.
PCT/JP2013/003996 2012-06-28 2013-06-26 Plasma-generating device and method for generating plasma WO2014002493A1 (en)

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