WO2008096454A1 - Pt rh based plasma generation electrode, plasma generation apparatus and plasma processing system - Google Patents

Pt rh based plasma generation electrode, plasma generation apparatus and plasma processing system Download PDF

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Publication number
WO2008096454A1
WO2008096454A1 PCT/JP2007/052803 JP2007052803W WO2008096454A1 WO 2008096454 A1 WO2008096454 A1 WO 2008096454A1 JP 2007052803 W JP2007052803 W JP 2007052803W WO 2008096454 A1 WO2008096454 A1 WO 2008096454A1
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WIPO (PCT)
Prior art keywords
electrode
plasma
metal
discharge
wear
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PCT/JP2007/052803
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French (fr)
Japanese (ja)
Inventor
Hirofumi Takikawa
Hajime Shiki
Takashi Okawa
Shigenobu Yamanaka
Akio Harada
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Toyohashi University Of Technology
Daiken Chemical Co., Ltd.
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Application filed by Toyohashi University Of Technology, Daiken Chemical Co., Ltd. filed Critical Toyohashi University Of Technology
Priority to PCT/JP2007/052803 priority Critical patent/WO2008096454A1/en
Priority to JP2008557185A priority patent/JP5368114B2/en
Priority to PCT/JP2008/052202 priority patent/WO2008096881A1/en
Publication of WO2008096454A1 publication Critical patent/WO2008096454A1/en

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    • 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
    • H05H1/26—Plasma torches
    • H05H1/32—Plasma torches using an arc
    • H05H1/34—Details, e.g. electrodes, nozzles
    • 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
    • H05H1/26—Plasma torches
    • H05H1/28—Cooling arrangements

Definitions

  • Pt'Rh electrode for plasma generation, plasma generator and plasma processing equipment (technical field)
  • the present invention relates to a plasma generating electrode, and more specifically, a plasma generating electrode that generates plasma of a supply gas by discharge, a plasma generating device that generates plasma using this electrode, and a surface of an object to be processed.
  • a plasma generating electrode that generates plasma of a supply gas by discharge
  • a plasma generating device that generates plasma using this electrode
  • a surface of an object to be processed Related to plasma processing equipment. Rice field
  • the discharge phenomenon that generates plasma is a glow discharge, abnormal Glow discharge, radio frequency (RF) discharge or corona discharge.
  • arc plasma generated by arc discharge has excellent controllability and high energy density at high temperatures because it is stabilized by cooling the airflow from the outer periphery in the injection direction with water cooling walls. It is used for various processing and surface treatment.
  • arc discharge is a discharge that occurs in a wide range of pressures from vacuum to atmospheric pressure.
  • Various source gases hereinafter referred to as “working gases”) can be easily turned into plasma, The desired surface treatment can be performed accordingly.
  • etching etching, surface coating, etc.
  • surface modification wetting properties
  • workpieces such as semiconductor products, metal products, glass products, processing parts, etc. Improvement, adhesion improvement, biocompatibility improvement), cleaning and desmear treatment, powder synthesis, thin film formation, etc. are possible.
  • a metal having a high melting point and a small work function is used, and tungsten (W), molybdenum (Mo), or the like is used as an electrode material.
  • the plasma arc torch described in Japanese Patent Application Laid-Open No. 10-29 96 4 45 (Patent Document 1) and Japanese Patent Application Laid-Open No. 11 1 2 8 5 8 3 4 (Patent Document 2) is shown in FIG. Indication In this way, a rod-shaped electrode 108 made of tungsten is internally provided, and a nozzle-shaped electrode 116 is disposed on the outer periphery of the tip of the rod-shaped electrode 108.
  • a voltage is applied between the rod-shaped electrode 108 and the nozzle-shaped electrode 1 16 to generate plasma, and the plasma P is ejected in a jet shape from the ejection port 1 16 a of the nozzle-shaped electrode 1 1 6. It has been done.
  • FIG. 24 is a schematic diagram of plasma generation in the conventional plasma generation electrode.
  • the electrode The wear material particles 109 are discharged from the electrode point 108 b on the front end surface 108 a.
  • an alloy in which copper (Cu) or silver (Ag) is blended with W or Mo is used to reduce electrode wear as described above.
  • Non-patent Document 1 Applications to engineering and environment control, Pure ana Applied Chemical, Vol. 666 (1 994) pp. 1 301—1 310 (Non-patent Document 1). Grinding arc type electrodes can generate arc plasma by generating an arc discharge at or near atmospheric pressure, creating a long-life, stable, high-purity arc plasma. There has been a demand for a mold electrode material.
  • Patent Document 1 Japanese Patent Laid-Open No. 10-296445
  • Patent Document 2 Japanese Patent Application Laid-Open No. 1 1-285834
  • Patent Document 3 Japanese Patent Application Laid-Open No. 2004-358623
  • the wear material particles 10 9 are emitted together with the plasma P from the electrode point 10 8 b. This is caused by the spark wear due to the explosion phenomenon of the electrode point 10 8 b and the oxidation wear that peels off the oxidized electrode front end face 10 8 a. Therefore, when plasma treatment is performed using a conventional plasma generating electrode, a large amount of wear material particles 1 0 9 adhere to the surface of the workpiece 1 2 2, resulting in high-precision surface processing and a uniform surface. Processing could not be performed. As a phenomenon in which the electrode material sublimates, evaporates and decreases, without being accompanied by the release of wear material particles, there is evaporation wear due to surface heating by Joule heat or plasma radiation.
  • FIG. 25 is an enlarged photograph of the electrode tip when arc plasma is generated using a conventional rod-shaped electrode 108 made of W or Cu.
  • 25 A As shown in the enlarged photographs of the upper and middle stages, tungsten oxide that has been peeled off by acid is formed on the periphery of the tip of the rod-shaped electrode made of tungsten (W). It can be seen that the wear material particles were released from the tip of the rod-shaped electrode.
  • 25 A From the electron microscope image shown in the lower part, it can be seen that the tip of the rod-shaped electrode becomes brittle due to oxidation and is easily peeled off.
  • FIG. 25 shows the tip of the rod-shaped electrode when arc plasma is generated using a copper rod-shaped electrode (Cu melting point: 1084 ° C) with a relatively low melting point. This shows the state.
  • Patent Document 3 The results of the plasma generation test using a rod-shaped electrode made of W or Cu are shown in Patent Document 3 when an alloy made of W and Cu is used as the electrode material. This confirms that no effective reduction of wear was made. That is, it is shown that W, Cu and their alloys are not suitable electrode materials for arc discharge electrodes. Therefore, when arc plasma is generated using an arc discharge electrode formed from a conventional electrode material, and surface processing or surface modification is performed by this arc plasma, wear material particles are released and are applied to the surface of the workpiece. Since the adhering and wearable material particles are mixed into the coating film as impurities, uniform surface treatment could not be performed.
  • Fig. 25 shows the results for the conventional plasma generating electrode used to generate arc plasma, but the same applies when plasma is generated by glow discharge, abnormal glow discharge, RF discharge or corona discharge. Result is obtained. That is, when the plasma is generated, the electrode surface reaches a temperature at which oxidation or evaporation can be caused, and when a conventional plasma generation electrode is used, wear material particles are generated due to electrode wear, and a desired plasma treatment is performed. It was difficult. In particular, in abnormal glow discharge, since the electrode becomes hot, an electrode for plasma generation with high heat resistance has been demanded.
  • the object of the present invention is to provide an electrode for plasma generation and a plasma generation apparatus with a long life, in which discharge of wear material particles is greatly reduced when plasma is generated by discharge, electrode wear is extremely low, It is an object of the present invention to provide a plasma processing apparatus that performs high-precision surface processing on a surface of an object to be processed and surface modification that imparts desired physical properties.
  • the present invention has been made to solve the above problems, and a first embodiment of the present invention is a plasma generation electrode of a plasma generation apparatus that generates plasma of a supply gas by discharge. At least the discharge surface of this plasma generating electrode is Pt! - a Y R h Y (0 ⁇ Y ⁇ 1 ) represented by P t plasma generation electrode formed from R h based metallic electrode material..
  • the second aspect of the present invention is the plasma generating electrode according to the first aspect, wherein the lattice constant a of the P t 'Rh-based metal is in the range of 3.80 A to 3.92 A.
  • a third mode of the present invention is the plasma generating electrode according to the first or second mode, wherein the melting point of the Pt′Rh-based metal is in the range of 1 773 ° (up to 1966 ° C.).
  • the fourth embodiment is a plasma generation electrode according to any one of the first to third embodiments, wherein the crystal structure of the Pt ⁇ Rh-based metal is a face-centered cubic lattice (FCC) structure.
  • the crystal grain size of the Pt—Rh-based metal is 0.5 ⁇ ! It is an electrode for plasma generation in the range of ⁇ 100 m.
  • the density p of the Pt ⁇ Rh-based metal is 1 '2.41 g,' cm 3 to 21.45 g / cm. This is a plasma generating electrode in the range of 3 .
  • a seventh aspect of the present invention is the plasma generating electrode according to any one of the first to sixth aspects, wherein the Pt-Rh-based metal has a Vickers hardness HV in the range of 5 OHv to l 30 Hv. It is.
  • the Pt'Rh-based metal when the weight ratio of Rh to the Pt-Rh-based metal is X wt%, the Pt'Rh-based metal The lattice constant a (A) of the above and the a%
  • the electrode for plasma generation wherein the lattice constant a is set by adjusting the weight ratio of Rh.
  • the weight ratio of Rh to the Pt.Rh-based metal is wt%
  • the Pt * Rh-based metal The density p (g / cm 3 ) and the weight%
  • the density p is set by adjusting the weight ratio of Rh.
  • any one of the first to tenth aspects when the weight ratio of Rh to the Pt ⁇ Rh-based metal is wt%, the Pt ⁇ Rh-based metal Vickers hardness HV (Hv) and X weight% of HV— X
  • a weight ratio of 1 ⁇ 11 occupying the P t • 1 1 group metal is set in a range of 0 wt% to 40 wt%. This is an electrode for plasma generation.
  • the electrode for plasma generation is arranged and at least a discharge surface of the high electric field electrode is formed from the electrode material. .
  • the high electric field electrode is a rod-shaped electrode
  • the low electric field electrode is a nozzle-shaped electrode having a plasma injection port
  • the electrode is a pendant electrode.
  • a fifteenth aspect of the present invention is the plasma generating electrode according to the fourteenth aspect, wherein at least the tip of the rod-shaped electrode is formed from the electrode material.
  • the high electric field electrode is a discharge surface.
  • a plasma generating electrode which is a protruding electrode having one or more protrusions on the side.
  • a seventeenth aspect of the present invention is a plasma generation apparatus for generating plasma using the plasma generation electrode according to any one of the first to sixteenth aspects.
  • a sixteenth aspect of the present invention is a plasma processing apparatus for performing plasma processing on a surface of an object to be processed by the plasma generating apparatus according to the fifteenth aspect.
  • the discharge surface of the plasma generating electrode for generating plasma has a discharge surface represented by P t 1 ⁇ R Y (0 ⁇ Y ⁇ 1). Therefore, it is possible to greatly reduce electrode wear and to suppress the release of wear material particles to a very small amount.
  • the formation of crystallites in the Pt—Rh alloy according to the present invention has been confirmed by observation with a scanning ion microscope.
  • the melting point of the Pt ⁇ Rh-based metal according to the present invention is low, whereas the melting point of W is 3704 ° C.
  • the melting point of Pt Balta metal is 1 773.
  • the melting point of Balta metal at 5 ° C and Rh is 1 960 ° C to 1 966 ° C.
  • the content ratio of the Rh element is indicated by the weight ratio, and the composition ratio Y and the weight ratio X are indicated.
  • oxidation resistance is an important factor for the wear of plasma generating electrodes, and that Pt and Rh have excellent oxidation resistance and heat resistance.
  • a plasma generation electrode also called “Pt'Rh electrode for plasma generation” in which at least the discharge surface is made of a P t ⁇ Rh metal.
  • This electrode for plasma generation can be used for generation of plasma by arc discharge, glow discharge, abnormal outlet discharge, RF discharge or corona discharge.
  • electrode wear at the time of plasma generation can be suppressed, and the electrode wear suppression effect becomes more prominent as the discharge surface becomes hot like abnormal glow discharge.
  • the plasma generating electrode according to the present invention is used, the release of the wear material particles is suppressed to a very small amount, so that the working gas is made into plasma and mixed with the raw material powder or the raw material gas. As a result, a high-purity coating film can be formed on the surface of the object to be processed by plasma spraying, thermal plasma C VD method, or the like.
  • thin film processing for example, microfabrication / removal of diamond thin film, micro-etching / removal of diamond-like force film
  • processing can be performed.
  • the object to be processed is a metal material
  • the plasma generated by the electrode for generating plasma according to the present invention is used for dissolving and scouring metal, thermal decomposition, reduction of metal oxide, etc., the material to be processed It is possible to prevent contamination of wear material particles.
  • the desired working gas is turned into plasma and irradiated onto the surface of the object to be processed, the release of wear material particles is suppressed, resulting in uniform surface modification (improvement of wettability, improved adhesion, biocompatibility) Improvement, etc.), cleaning and desmear treatment can be performed with high efficiency.
  • the Pt * Rh-based metal according to the present invention contains impurities.
  • An electrode material having a small solid solution and suitable workability can be provided, and a discharge surface of a plasma generating electrode having desired physical properties and shape can be provided from this electrode material. That is, when the lattice constant is smaller than 3.8 O A, the hardness increases and machining becomes difficult.
  • the lattice constant a is larger than 3.92 A, impurities are easily dissolved, and it is difficult to impart desired characteristics to the plasma generating electrode.
  • the present inventors have clarified a lattice constant suitable as the electrode material and have determined the range of the lattice constant.
  • the melting point of the Pt-Rh-based metal is set in a range of 1 77 3 ° C to 1 96 6 ° C, the discharge surface is formed during plasma generation. It is suitably softened and the release of the wear material particles can be suppressed.
  • One of the causes of the generation of wear material particles is an explosion phenomenon (spark wear) on the discharge surface.
  • spark wear spark wear
  • a high melting point metal material W, Mo, etc.
  • the melting point can be set in a suitable range, the discharge surface is suitably softened during plasma generation, and a spark is generated. Release of wear material particles due to wear can be suppressed to a very small amount. If at least the discharge surface of the electrode for plasma generation is formed from a Pt-Rh alloy, adjust the Rh content relative to Pt according to the application of the plasma and the type of working gas, 1 7 7 3 ° C The melting point of the electrode material can be set to a suitable temperature within a range of ⁇ 196 6 6 ° C.
  • the temperature is from 1 77 3 ° C to 1 96 6 ° C.
  • the melting point is more preferably set in a range of 1 77 3 ° C to 1 93 2 ° C, and 1 8500 ° C to 19 It is clear from experiments that it can be optimal when it is in the range of 3 ° C.
  • the Pt metal or Pt—Rh alloy forming the Pt ⁇ Rh-based metal forms a crystallite, and the crystal structure of the crystallite is a face-centered cubic lattice. (FCC) structure.
  • FCC face-centered cubic lattice.
  • face-centered cubic lattice metals are easy to process and have a high filling rate, which suppresses solid solution of impurities. Therefore, if the Pt′Rh-based metal according to the present invention is used for the electrode material, it has suitable electrical characteristics, and the electrode material is easily processed into a predetermined shape to constitute a plasma generating electrode. be able to.
  • the crystal grain size of the Pt ⁇ Rh-based metal is in the range of 0.5 ⁇ m to 100 ⁇ m, the sputtering resistance suitable for the electrode material Is provided, and the discharge surface can be held uniformly. It has been confirmed that when the crystal grain size is larger than 100 ⁇ m, the sputtering resistance is deteriorated and a discharge surface suitable for plasma generation cannot be maintained. When the crystal grain size is smaller than 0.5 ⁇ m, the spatter resistance is improved, but a very large amount of wear particles tends to be generated easily. Therefore, the crystal grain size is 0.5 ⁇ II! By setting the thickness within a range of ⁇ 100 ⁇ m, it is possible to generate a uniform plasma with less wear particles using the plasma generating electrode according to the present invention.
  • the density p of the P t .R h-based metal is 1 2.4 1 g. ./'cm 3 to 21.45 g, / cm 3 , so that the amount of impurities contained in the electrode material can be reduced and the discharge surface becomes porous during electrode formation and / or plasma generation. Can be suppressed.
  • the density p is greater than 21.45 g / 'cm 3 , the absolute amount of impurities increases and it becomes difficult to suppress the contamination of the impurities, and the electrical characteristics of the plasma generating electrode must be set to a predetermined value. There is a possibility that the impurities are mixed in the plasma together with the wear particles. Further, the density p is less than 12.
  • the Vickers hardness HV of the Pt.Rh-based metal is in the range of 50 Hv to l 3 OH V, the generation of wear particles can be reduced and a suitable hardness can be achieved. It can be applied to the discharge surface.
  • the picker hardness HV exceeds 130 HV, the discharge surface becomes brittle and it becomes difficult to process the plasma generating electrode into a predetermined shape.
  • the generation of the wear particles tends to increase. Therefore, the Pt ⁇ Rh metal according to the present invention has a Vickers hardness HV set in the range of 5 OH v to 13 OHv, so that it has a suitable durability and generates a small amount of wear particles. It is possible to provide a plasma generating electrode having the following shape.
  • the lattice constant a (A) of the P t 'Rh-based metal and the a-X relational expression of the weight% is +
  • the discharge surface can be formed from an electrode material having a predetermined lattice constant a by adjusting the weight ratio of Rh.
  • the present inventors have clarified the lattice constant of a suitable electrode material from the results of plasma treatment using the electrode for plasma generation and the analysis based on the X-ray diffraction (XRD) measurement of the electrode material, and the results of these experiments. From the above, the a-X relational expression is derived. That is, by changing the weight ratio of Rh, It is derived what dependency the lattice constant a has on the X weight% in a range in which the generation of the laser is possible. Therefore, an electrode material having a desired lattice constant can be selected depending on the content of R h to form a plasma generating electrode.
  • the lattice constant a can be set to 3.874 people 0.02 A. That is, the lattice constant a can be set within the range of 3.854A to 3.894A.
  • the lattice constant a can be set to 3.863 ⁇ 0.02A (within a range of 3.843 A to 3.883 A). Accordingly, by adjusting the weight ratio of Rh, the lattice constant a can be easily set to the above-described lattice constant range of 3.80 A to 3.92 A shown in the second embodiment.
  • the first T-X relational expression of the melting point T (° C) of the P t 'Rh-based metal and the X weight% is
  • the melting point T (° C.) can be set to a predetermined temperature range by adjusting the weight ratio of Rh.
  • the melting point T (.C) is 1881 ⁇ 70. C (in the range of about 181 1 ° C to about 1951 ° C), and when the X wt% is 40 wt%, the melting point T (° C) is 18 96 ⁇ 70. C (in the range of about 1826 ° C to about 1966 ° C) can be further set to the X weight.
  • the weight ratio of Rh is adjusted in the range of 0 ⁇ 30, and the melting point T (° C) is more reliably set within the predetermined temperature range. be able to.
  • the dependence of the melting point T (° C) on the Rh content is derived by an approximately linear function.
  • the Rh content dependency is not strictly a linear function, the slope of the T-X relation varies greatly between 0 ⁇ X ⁇ 30 and 30 ⁇ X ⁇ 100. Therefore, based on the measurement data in the range of 0 ⁇ X ⁇ 30, the second T—X relational expression is derived, and the weight% is 0 wt% to 30 wt%. 1 ⁇
  • T can be set.
  • the second ⁇ one X relationship if the weight percent is 30 weight 0/0, the melting point T (° C) to 1890 ⁇ 15. C (range from about 1875 ° C to about 1905 ° C).
  • the melting point T (° C.) As described above, by setting the melting point T (° C.) within a predetermined temperature range, it is possible to improve the workability of the electrode material, and to suppress the generation amount of the wear particles at the time of plasma generation. it can. Therefore, since the melting point T (° C.) can be easily set depending on the Rh content of the Pt ⁇ Rh-based metal, a high-performance plasma generating electrode can be manufactured at a low cost.
  • the density of the Pt ⁇ Rh-based metal /) (g.Zcm 3 ) and the weight percent p—X relational expression are
  • the density p can be set within a predetermined density range by adjusting the weight ratio of Rh.
  • the p—X relational expression is derived by clarifying the density of a suitable electrode material based on the plasma processing result using the plasma generating electrode and the density measurement. As described above, the impurity content and the like change according to the density p (g cm 3 ), which affects the electrical characteristics of the plasma generating electrode, such as the resistance value. Therefore, the density p of the P t ⁇ Rh-based metal can be easily controlled using the p-X relational expression, so that a plasma generating electrode having desired electrical characteristics can be provided. Said X weight.
  • the density p can be set to 18.26 ⁇ 0.6 g.Zcm 3 (within a range of about 17.66 gcm 3 to about 18.86 gZcm 3 ),
  • the melting point T (° C) is 17.51 ⁇ 0.6 g / cm 3 (about 16.91 g, cm 3 to 18.11 about g / cm 3 (Within range).
  • the Pt ⁇ Rh-based metal pitch hardness HV (Hv) and the weight% HV-X relational expression are:
  • the Vickers hardness HV can be set within a predetermined range by adjusting the weight ratio of Rh. As described above, by setting the Vickers hardness HV within a predetermined range, suitable workability is imparted to the electrode material. The generation of wear particles during plasma generation can be suppressed.
  • the Vickers hardness HV For example, if the previous SL X weight 0/0 is 30 weight 0/0, it is possible to set the Vickers hardness HV to 135 ⁇ 15H V (in the range of about 120 HV ⁇ about 1 50 HV), wherein X wt% can be set in the case of 20 weight 0/0, the Vickers hardness HV of (Hv) 107 ⁇ 15 ⁇ V (in the range of about 92Ita V to about 1 22 ⁇ V).
  • the electrode material is a suitable mechanical material. It has strength and can extend the life of the plasma generation electrode and can be easily processed into a desired shape. Therefore, it is possible to provide plasma generation electrodes having various shapes depending on the application, such as for pen jets and grinding arcs.
  • the Rh content of the Pt ⁇ Rh-based metal increases, the amount of wear of the electrode in the arc discharge decreases.
  • the Rh weight ratio exceeds 40% by weight, the present inventors Experiments have confirmed that the mechanical strength is significantly reduced.
  • the hardness and tensile strength suitable for the plasma generating electrode according to the present invention are tough. Etc. are attached. Furthermore, in the above experimental results, more suitable mechanical strength can be obtained when the weight ratio of Rh is set to 10 to 30% by weight.
  • the lattice constant a 3. 863 ⁇ 0. 02A Can be set in the range of ⁇ 3.908 ⁇ 0.02 A.
  • the melting point T can be set in a range of 1836 ⁇ 70 ° C. to 1896 ⁇ 70 ° C., and the density /) is 17.51 ⁇ 0.6 ⁇ no 111 3 to 20.87 ⁇ 0. Can be set in the range of 6 g / cm 3 .
  • the discharge surface on the facing surface side of the high field electrode is Due to the force formed from the electrode material, it is possible to suppress the release of wear material particles due to a high electric field.
  • the high electric field electrode is applied with an absolute larger voltage and corresponds to a high voltage electrode (cathode) that emits electrons
  • the low electric field electrode is, for example, for example, it corresponds to a low voltage electrode (anode) to which a voltage having a smaller absolute value is applied, such as a ground electrode.
  • the reverse may be the case, such as when the high field electrode is the anode and the low field electrode is the cathode.
  • the electrode having such a structure is compared to the opposite electrode.
  • the electric field concentrates to form a high electric field electrode.
  • the opposing electrode has a lower electric field or applied voltage than the high electric field electrode, and constitutes a low electric field electrode.
  • the high electric field electrode is a rod-shaped electrode
  • the low electric field electrode is the nozzle-shaped electrode
  • the electrode constitutes a pendant electrode.
  • the pen-type electrode is composed of a nozzle-like electrode having a plasma injection port on the tip side of the rod-like electrode, and a voltage is applied to the rod-like electrode and the nozzle-like electrode.
  • the pen jet type electrode it is possible to cool the plasma flow by providing a water cooling part on the outer periphery of the plasma generating part or by introducing an air flow, to easily control the size of the flux and to stabilize it. it can. Therefore, by forming the discharge surface from a Pt-Rh-based metal and generating a high purity jet plasma flow, the plasma is irradiated to a predetermined region on the surface of the object to be processed, thereby depositing impurities. ⁇ Uniform surface processing and surface modification can be performed without mixing.
  • a tubular electrode can be used as the rod-shaped electrode, and a working gas is supplied into the tube, and a voltage is applied to the tip of the tubular electrode and the nozzle surface of the nozzle electrode to generate arc plasma of the working gas.
  • a working gas is supplied into the tube, and a voltage is applied to the tip of the tubular electrode and the nozzle surface of the nozzle electrode to generate arc plasma of the working gas.
  • At least the tip of the rod-shaped electrode is P t ⁇ R Since it is integrally formed of an h-based metal, it is possible to easily manufacture a long-life plasma generating electrode with very little electrode wear. That is, since at least the entire tip of the rod-shaped electrode is formed from the electrode material, no special processing such as coating of the Pt ⁇ Rh-based metal rod-shaped electrode is required, and the discharge surface is The rod-shaped electrode made of Pt ⁇ Rh-based metal can be manufactured. Furthermore, since at least the entire tip of the rod-shaped electrode is formed from the Pt ⁇ Rh-based metal, the discharge surface of the Pt ⁇ Rh-based metal may be lost due to the accumulation of a small amount of electrode wear.
  • the life of the plasma generating electrode can be extended.
  • the tip formed from the Pt'Rh metal it can be used as an electrode for plasma generation, and the entire rod-shaped electrode is formed from an expensive PtRh metal. Compared with the case, the manufacturing cost of the plasma generating electrode can be reduced.
  • the high electric field electrode is a protruding electrode having one or more protrusions on the discharge surface side
  • an electric field is applied to the one or more protrusions formed on the discharge surface. And can generate plasma with high efficiency.
  • the force that the discharge surface of the protruding electrode that concentrates the electric field is formed from the Pt ⁇ Rh-based metal suppresses electrode wear and has high purity with very little contamination of wear material particles. The plasma can be generated with high efficiency.
  • the plasma generating apparatus that stably injects high-purity plasma for a long time.
  • the working gas supplied to the plasma generating apparatus according to the present invention may be anything in the form of gas or vapor.
  • gas or vapor For example, indoor air, dry air, humidified air, helium, argon, oxygen, nitrogen, hydrogen, hydrogen sulfide,
  • a high-purity plasma in which the wear material particles are very little mixed can be generated by appropriately selecting from hydrocarbon gas and mixed gas thereof according to the purpose. It is also possible to mix powder with these working gases.
  • the pressure range of the working gas is not limited to the following range, but the lower limit of the pressure is about 1 to 10 (about 0.3 latm) of atmospheric pressure as a pressure condition with less evaporation of the electrode.
  • the upper limit of the pressure is preferably up to about 10 atm as a value for safely using the working gas. Further, it is more preferable that the pressure of the working gas is set in a range of 0.5 to 5 atm. 52803
  • a desired plasma can be stably generated by a plasma generating apparatus provided with a pendant type electrode and a grinding arc type electrode.
  • the surface of the object to be processed is subjected to the plasma treatment by the plasma generating apparatus according to the eighth aspect, so that the wear material particles adhere, deposit, and mix as impurities on the surface of the object to be processed This can be prevented. Furthermore, since electrode wear is suppressed, surface treatment of the surface of the workpiece can be continuously performed for a long time.
  • the plasma processing apparatus of the present invention the above-described plasma spraying, thermal plasma CVD method, thin film processing, metal dissolution and thermal decomposition, metal oxide reduction, surface modification, cleaning and desmear treatment, powder Plasma treatments such as synthesis / treatment and thin film formation can be performed with extremely reduced contamination / deposition of the wear material particles.
  • FIG. 1 is a schematic configuration diagram of a plasma processing apparatus having a pen jet electrode according to the present invention.
  • FIG. 2 is a photograph showing an image of a plasma emitted from an injection port of a pen jet type plasma processing apparatus according to the present invention.
  • FIG. 3 is a schematic cross-sectional view of a plasma generating apparatus having a double-electrode water-cooled pen jet electrode according to the present invention.
  • FIG. 4 is a schematic cross-sectional view of the electrode tip according to the present invention.
  • FIG. 5 is an enlarged photograph of the tip of the Pt ⁇ Rh-based metal electrode according to the present invention and the tip of each electrode made of Pt—Ir alloy in the comparative example, taken after arc discharge. is there.
  • FIG. 6 is an enlarged photograph showing the Pt metal electrode tip according to the present invention imaged after plasma generation.
  • FIG. 7 is an enlarged photograph after discharge of each electrode tip portion made of the Pt—Ir alloy (7A) and the Pt—W alloy (7B) as comparative examples.
  • FIG. 8 is a graph showing the power dependence of the electrode wear amount using the electrode tip of the Pt metal and Pt—Rh alloy according to the present invention and the Pt-Ir alloy electrode tip of the comparative example.
  • FIG. 9 is a table of workpieces that have been plasma processed by the plasma processing apparatus according to the present invention. It is an optical microscope photograph figure of a surface.
  • FIG. 10 is a graph showing the cumulative amount of wear (mg) with respect to the cumulative discharge time (m i n) of the electrode tip made of Pt ⁇ Rh metal according to the present invention and various comparative metals.
  • FIG. 11 is a graph showing the discharge time dependence of the amount of wear in a plasma generating electrode using a Pt—Rh alloy according to the present invention as an electrode material.
  • FIG. 12 is a graph showing the XRD analysis results of the Pt ⁇ Ph metal according to the present invention.
  • FIG. 13 is an enlarged graph of the inside of the broken line in FIG.
  • FIG. 14 is a graph showing the lattice constant with respect to the Rh content (% by weight) of the Pt ⁇ Rh metal according to the present invention.
  • FIG. 15 is a phase diagram of a Pt—Rh alloy which is an electrode material according to the present invention.
  • FIG. 16 is a table showing the melting points of the Pt ⁇ Rh metal and other metals and alloys according to the present invention.
  • FIG. 17 is a graph plotting the melting point of the Pt ⁇ Rh metal according to the present invention against the weight ratio of Rh (X wt%).
  • FIG. 18 is a graph in which the melting point of the Pt ⁇ Rh metal according to the present invention is plotted against the weight ratio (% by weight) of Rh. (0% to 30% by weight)
  • FIG. 19 is a graph in which the density p of the Pt ⁇ Rh metal according to the present invention is plotted against the weight ratio of Rh (X wt%).
  • FIG. 20 is a graph plotting the Vickers hardness HV of the Pt ⁇ Rh-based metal according to the present invention against the weight ratio (% by weight) of Rh.
  • FIG. 21 is a schematic configuration diagram of a pendant plasma processing apparatus having a tubular rod electrode according to the present invention.
  • FIG. 22 is a schematic configuration diagram of a plasma generating portion in which the plasma generating electrode according to the present invention is a grinding arc type electrode.
  • FIG. 23 is a schematic configuration diagram in the case where the plasma generating electrode according to the present invention includes a sawtooth electrode.
  • FIG. 24 is a schematic diagram of plasma generation in a conventional plasma generation electrode.
  • Fig. 25 is an enlarged photograph of the electrode tip when arc plasma is generated using a conventional rod-shaped electrode made of W or Cu.
  • FIG. 1 is a schematic configuration diagram of a plasma processing apparatus 2 having a penjet electrode according to the present invention (hereinafter also referred to as “penjet plasma processing apparatus”).
  • the plasma processing apparatus 2 includes a plasma generating apparatus 7 including a plasma generator 4 and a power supply unit 6, and a processing unit (not shown) force on which the workpiece 22 is placed.
  • the plasma generator 4 is provided with a pen jet electrode composed of a rod-shaped electrode 8 and a nozzle-shaped electrode 16.
  • the guide body 24 constituting the plasma generator 4 is provided with the rod-shaped electrode 8, and the nozzle-shaped electrode 16 is disposed on the side of the injection port 16b of the guide body 24.
  • the working gas 28 supplied from the gas inlet 30 circulates in the guide main body 24, is supplied to the plasma generation unit 4a and is converted into plasma, and the gas supply pressure of the working gas 28 is used to
  • the plasma P is ejected as a flux from the injection port 16 b of the nozzle electrode 16.
  • FIG. 2 shows a photograph of the plasma P emitted from the outlet 16 b of the pen jet type plasma processing apparatus 2 according to the present invention.
  • dry air is used as the working gas 28, the gas supply pressure is set to 0.2 MPa, and the gas flow rate is set to 20 L, / min.
  • the plasma stream comprising N 2 + and 0 2 + and the like are delivered to the object 2 2, the actuating As gas 28, select from dry air, humidified air, helium, argon, oxygen, nitrogen, hydrogen, hydrogen sulfide, hydrocarbon gas and mixed gas according to the purpose to produce the desired plasma P can do.
  • the working gas can be supplied to the gas inlet 30 using a commercially available gas cylinder, compressor, blower, nitrogen gas supply device, or the like.
  • commercially available valves, mass flow controllers, and rotameters can be used to control the flow rate of working gas.
  • a regulator (not shown) for controlling the gas supply pressure is arranged.
  • a water-cooled electrode cap 18 is provided on the outer periphery of the guide body 24, and the nozzle electrode 16 is connected to the ground 20 through the water-cooled electrode cap 18.
  • the cooling water 18 a By circulating the cooling water 18 a, the nodular electrode 16 and the plasma generating part 4 a are cooled, and damage to the nodular electrode 16 and plasma diffusion are prevented.
  • an insulating portion 26 is formed around the plasma generating portion 4 a to prevent an electric field from being formed between the water-cooled electrode cap 18 connected to the ground 2 ′ 0 and the rod-shaped electrode 8.
  • the rod-shaped electrode 8 is composed of an electrode tip portion 10 made of a Pt ⁇ Rh-based metal and an electrode base end portion 12 made of a base metal having a high melting point such as tandastene or stainless steel.
  • the distal end portion 10 and the electrode base end portion 12 are electrically connected by a sleeve 14 formed of Cu or Ni having good electrical conductivity. Therefore, when the wear of the electrode tip portion 10 increases due to long-term use, only the electrode tip portion 10 made of Pt′Rh-based metal can be replaced.
  • the electrode tip 10 is made of an electrode material having a diameter of 1.6 mm and a length of 9 to 1 O mm. The length and diameter of the electrode tip 10 can be appropriately changed. In the case of the pen jet type electrode of FIG. 1, the diameter of the electrode tip 10 is such that the electric field is concentrated on the electrode tip surface 10a. It is preferable to set to about 0.5 mm to 3 mm
  • the working gas 18 flows from the gas inlet 30 of the plasma generator 4 between the side surface of the rod-shaped electrode 8 and the guide body 24, and the working gas 18 is generated as a plasma. Supplied to part 4a.
  • the electrode front end surface 10a or the electrode front end surface 10a and the vicinity thereof become a discharge surface, and the working gas 28 supplied to the plasma generating unit 4a is composed of the electrode front end surface 10a and the nozzle-like electrode.
  • Plasma is generated by arc discharge between the inner surface 16 a and the surface of the workpiece 22 is irradiated with plasma P from the injection port 16 b.
  • the interelectrode gap from the electrode tip surface 10 a of the rod-shaped electrode 8 to the closest position of the nozzle-shaped electrode is set to about 2 mm, and the injection port 16 a and the workpiece 2 2 The irradiation distance d between them is set to 10 mm.
  • the potential applied to the rod-shaped electrode 8 is a pulse current supplied from the power supply unit 6. Is granted by.
  • the power supply unit 6 is connected to a pulse modulator 3 2 connected to a three-phase AC power supply 3 1, an LC series circuit comprising a coil 40 and a capacitor 4 2, and an earth 4 1. Consists of high voltage transformers 3-8. With the pulse modulator 3 2, the pulse frequency and pulse width can be adjusted freely. Further, the voltage is boosted by the high voltage transformer 38 and a high voltage pulse is applied between the rod electrode 8 and the grounded nozzle electrode 16.
  • the decrease in the charging voltage in the capacitor 42 is suppressed by the coil 4 Q, and the potential applied to the electrode tip surface 10 a by the discharge from the capacitor 42 is held at the dischargeable potential.
  • the pulse width of the applied high voltage pulse is set to about 2 H s and the pulse frequency is set to about 20 kHz.
  • arc discharge is caused by a high voltage pulse between the nozzle-like electrode 16 connected to the ground 20 through the water-cooled electrode cap 18 a and the electrode tip surface 10 a.
  • Plasma P is generated by thermionic emission, field emission, or Schottky emitted electrons.
  • a voltage of 10 to 15 kV is applied to the gap between the electrodes by the high voltage panel, and the voltage of the gap between the electrodes is reduced to about 5 kV by arc discharge.
  • the pulse modulator 3 2 is provided with a power regulator 3 4 and a wattmeter 3 6, and the supplied power can be freely adjusted, and the test described later is performed in order to maintain the arc discharge potential. Is set in a range of 1 0 0 W to 5 0 0 W.
  • the diameter of the electrode tip portion 10 made of Pt ⁇ Rh-based metal is about 1.6 mm (cross-sectional area of the electrode tip surface 10 a: about 2 mm 2 ).
  • the pulse frequency is about 30 kHz
  • the pulse width is about 2 ⁇ s
  • the flow rate of the supplied working gas is about 20 L / 'mi ⁇
  • the supplied power is When set to a value, a suitable plasma can be generated continuously or intermittently by arc discharge.
  • the average power may be set to 20 OW (10 OW / mm 2 ) or less
  • the maximum applied voltage is set to about 5 kV
  • the maximum peak current is set to 10 A (5 A / mm 2 ) or less.
  • the average current density of the supplied current is preferably set to a predetermined value or less, and if the cross-sectional area is increased, the supplied power is increased.
  • the amount of plasma generated can be increased. That is, if the density of the average power is set to 10 ow.z mm 2 or less, the plasma generation amount can be appropriately adjusted according to the cross-sectional area.
  • FIG. 3 is a schematic cross-sectional view of a plasma generating apparatus 7 having a double-electrode water-cooled pendant electrode according to the present invention, and a water-cooled portion 15 is provided on the outer periphery of the electrode base end portion 12.
  • a water-cooled portion 15 is provided on the outer periphery of the electrode base end portion 12.
  • the cooling water 15a By circulating the cooling water 15a, the electrode base end portion 12 and the electrode tip end portion 10 are cooled, and evaporation of the electrode material is suppressed, so that the amount of electrode wear can be reduced. Therefore, plasma P can be generated over a long period of time. Furthermore, it is possible to prevent the generation of plasma from the outer periphery in the vicinity of the electrode tip surface and the evaporation of the electrode material, and a suitable jet plasma P is generated.
  • the flow rate and / or temperature of the cooling water 15 a and 18 a can be adjusted according to the injection amount of the plasma P, and the plasma generator 7 can be operated stably for a long time. Furthermore, if the water cooling part 15 is brought close to the electrode tip surface 10Oa, the periphery of the outer edge of the electrode tip surface 1Oa is also cooled, so that plasma diffusion is suppressed and the flux of the generated plasma P is reduced. It is possible.
  • FIG. 4 is a schematic cross-sectional view of the electrode tip 10 according to the present invention.
  • the entire tip 10 of the electrode tip is formed of a Pt ⁇ Rh-based metal.
  • the electrode tip portion 10c is formed by P coating or vapor deposition.
  • the tip of the electrode can be formed by forming a coating film 10 b of t ⁇ Rh-based metal.
  • P t-R h alloy is generally more expensive than P t pure metal, and reducing the amount of P t—R h alloy used reduces the manufacturing cost of the plasma generating electrode according to the present invention. can do.
  • the coating film 10b When the coating film 10b is formed of a Pt-Rh alloy containing a relatively large amount of Rh, and the electrode tip body 10c is made of Pt metal, the interface and A P t — R h alloy is formed near the interface.
  • the thickness T 2 of the coating film 10 b coated on the electrode tip surface 10 a where the electric field concentrates is preferably thicker than the thickness 1 of the coating film i 0 b on the side surface. Further, as shown in (4 B), the coating film 10 b may be formed only in a predetermined region including the discharge surface. Thickness T. Is preferably 0.1 mm or more, 0.5 More preferably, it is at least mm.
  • Fig. 5 is an enlarged photograph of the tip of the Pt.Rh-based metal electrode according to the present invention and the electrode tip of each of the Pt-Ir alloy electrodes of the comparative example taken after arc discharge. It is.
  • the Rt content of the Pt-Rh alloy used as the electrode material is 10% by weight, and the Ir content of the Pt—Ir alloy is 20% by weight.
  • power of 500 W is supplied to the pulse modulator, and when using the electrode tip of Pt 1 Ir alloy, 4 00 W power is being supplied. Dry air is used as the working gas.
  • the shape of the electrode tip is almost the same as before the discharge when the supply power is 500 W. Have.
  • 5B when an electrode tip made of a Pt—Ir alloy is used, a remarkable deformation is seen in the shape of the electrode tip at a supplied power of 40 OW. This is thought to be due to the fact that the electrode tip was heated and melted by ion bombardment and the like, and the electrode wear increased due to metal evaporation, oxidation wear, spark wear, and the like.
  • the electrode tip made of the P t—R h alloy according to the present invention has almost no electrode wear, and the release of wear material particles is extremely reduced. This shows that the plasma generating electrode can generate high-energy arc plasma with high efficiency by applying a high voltage.
  • Fig. 6 shows an enlarged photograph of the Pt metal electrode tip according to the present invention imaged after plasma generation.
  • Fig. 6 shows the P t—Ir alloy (7A) and P as comparative examples.
  • An enlarged photograph after discharge of each electrode tip composed of t—W alloy (7 B) force is shown.
  • the results in Fig. 6 and Fig. 7 are the results of arc discharge for 10 minutes with the supplied power of 3 ° OW.
  • Each electrode tip has a diameter of about 1.6 mm and a length of 9 mm.
  • the Pt metal electrode according to the present invention has good oxidation resistance, and the surface of the tip of the electrode after the generation of the plasma is Have the same shape.
  • 6 O In the scanning electron microscope image (SEM image) shown in C), micropores are slightly formed, but the surface state before the discharge is maintained substantially.
  • FIG. 8 is a graph showing the electrical dependence of electrode wear using the electrode tip of the Pt metal and Pt—Rh alloy according to the present invention and the Pt—Ir alloy electrode tip of the comparative example.
  • FIG. The horizontal axis shows the supplied power (Electric power (W)), the vertical axis shows the amount of retirement (Erosion amount (mg)), and the discharge duration (Discharge duration time) is set to 10 minutes.
  • the amount of wear is estimated from the mass difference between the front and rear electrode portions.
  • the double-electrode water-cooled pen jet type plasma generator shown in Fig. 3 is used.
  • the supplied power is hardly worn up to 300 W, or the amount of wear is suppressed to a very small amount.
  • the supplied power reaches 400 W, the amount of wear increases rapidly, generating high-energy, high-purity arc plasma. In this case, it is not suitable as an electrode material.
  • Figure 6 shows that Pt metal is an excellent electrode material when the power supply is 40 OW or less.
  • the electrode function itself tends to deteriorate, and measurement at 50 OW is not performed. That is, at the tip of the electrode made of P t—I r alloy, when the power supplied reaches 300 W, the amount of wear increases clearly, and the electrode wear tends to increase rapidly in the range exceeding 300 W. This shows that it is difficult to use t—Ir alloys as electrode materials. Conversely, if the power supplied to the plasma is 300 W or less, a Pt—Ir electrode can also be used.
  • FIG. 9 is an optical micrograph of the surface of an object to be processed that has been subjected to plasma processing by the plasma processing apparatus according to the present invention.
  • An Si substrate is used as the object to be processed, and a vaginal field image of the surface of the Si substrate after the plasma processing is taken with an optical microscope.
  • (9 A) is an unprocessed substrate, Untreated table)]].
  • 9B) and (9C When using a plasma processing device equipped with a Pt—Rh alloy plasma generation electrode, as shown in (9B) and (9C), almost no wear material particles adhere to the supply power of 100W and 200W. It can be seen that it is in the same state as the untreated substrate surface in (9A). Furthermore, when the power supply is increased from 200W to 400W, only slightly worn material particles adhere as shown in (9D) and (9E).
  • Fig. 10 shows the cumulative discharge time at the tip of an electrode made of Pt ⁇ Rh-based metal according to the present invention and various types of metals as comparative examples (
  • FIG. 4 is a graph showing an accumulated erosion amount (mg). Using the electrode tip formed from the above electrode material in the double-electrode water-cooled pendant plasma generator shown in Fig. 3, the amount of electrode wear for each discharge time was measured, and these values were plotted. In this measurement, the power supply is set at 300 W. The diameter of each electrode tip is about 1.6 mm, and has the same tip surface area.
  • the amount of wear is suppressed to a very small amount even for a long discharge.
  • the amount of wear at the tip of the Pt-Ph alloy electrode after about 60 minutes of discharge is about 0.6 mg, which is much different from other metals.
  • an increase in the amount of wear is suppressed compared to the metal of the comparative example, and the amount of wear is about 2.4 mg after 60 minutes of discharge.
  • the amount of wear reaches about 2.9 mg.
  • Cu metal the amount of wear has already reached about 2.4 mg after 30 minutes of discharge, and in the case of W metal and Pt—W alloy, about 50 mg of W metal for 5 minutes of discharge.
  • About 7 mg of Pt—W alloy is worn out.
  • Figure 11 shows the cumulative discharge time (Accumulated wear amount (ni g)) of the plasma generation electrode using the Pt-Rh alloy according to the present invention as the electrode material. It is a graph showing the dependence, and the wear amount of the electrode is measured by changing the Rh content of the Pt-Rh alloy.
  • the mass ratio of Rh in the Pt—Rh alloy is 10%, it is indicated by a circle ( ⁇ ), when it is 20% by a triangle ( ⁇ ), and when it is 30% by a square (mouth).
  • the supplied power is 300W, and the diameter of each electrode tip is set to about 1.6mm, including the Pt electrode ( ⁇ ), which is a comparative example.
  • the amount of wear for each discharge time is measured, and the total value is plotted.
  • the wear amount of the electrode decreases, and when the Rh mass ratio is 30%, the Pt electrode Compared with, the amount of wear has been reduced to about 1'2.
  • the life of the plasma generating electrode is approximately doubled and the generation of impurities is suppressed to about half, and a more suitable plasma generating electrode can be obtained by increasing the Rh content.
  • T The tip of the Pt metal electrode has a larger amount of accumulated wear than when the Pt-Rh alloy is used, but the amount of accumulated wear increases compared to the other metals shown in Fig. 10. Needless to say, it is slight.
  • the mechanical strength of the plasma generating electrode is remarkably lowered when the mass ratio of Rh exceeds 40%. That is, when the mass ratio of Rh is set in the range of 1 to 40%, suitable hardness, tensile strength, toughness, and the like are imparted to the plasma generating electrode according to the present invention. Furthermore, in the above-described test on mechanical strength, more suitable mechanical strength is obtained when the mass ratio of Rh is set to 10 to 30%.
  • Rh-based metals have excellent characteristics as electrode materials for plasma generation electrodes based on the more essential physical properties of metals
  • present inventors -Various physical property values of Rh-based metals are measured, and appropriate physical property values are identified from the correspondence with electrode performance. The measurement results of various physical properties related to Pt ⁇ Rh metals are shown below.
  • the present inventors focused on the lattice constant as a factor that makes the Pt ⁇ Rh metal according to the present invention suitable as an electrode material, and based on the X-ray diffraction (XRD) analysis, the lattice constant of the Pt'Rh metal was determined. The number is derived.
  • Rh contains 20 weight 0 / o Pt—Rh alloy (Pt—Rh 20%) and Rh contains 30% by weight
  • the X-ray diffraction strength graph of the P t—Rh alloy (P t—Rh 30%) is shown.
  • the lattice constant a is obtained by calculating the interplanar distance d from the XRD diffraction angle 2 ⁇ corresponding to the (1 1 1) plane of the P t ⁇ Rh group metal in the broken line in Fig. 12.
  • FIG. 13 is an enlarged graph showing the inside of the broken line in FIG. 12, and it can be seen that the lattice constant of the P t .Rh metal according to the present invention clearly changes according to the Rh content. .
  • XRM analysis using Rh Balta metal is also performed.
  • Table 1 shows the weight of Rh ′.
  • Examples 1 to 4 describe / 0 (Weight Percent of Rli) and lattice constant a (Lattice Constant) obtained from the XRD analysis.
  • the Rh metal shown as a comparative example (Rh 100% by weight in the table) has poor processability and is difficult to use as an electrode material. That is, when the lattice constant a in Table 1 is 3.797 A or more, the workability of the electrode material is lowered, which indicates that it is difficult to use it as an electrode for plasma generation.
  • the present inventors have determined that the lattice constant a of a metal preferable as an electrode material is 3.80 or more from the dependence of the Rh content on the workability of the electrode material.
  • Rt% of Rt'Rh metal and lattice constant a (A)
  • the lattice constant of Cu metal is about 3.608A
  • the lattice constant of W metal is about 3.158A.
  • Cu metal and W metal are used as plasma generation electrodes.
  • the lattice constant of the electrode material When the number is smaller than 3.80 A, not only the workability deteriorates but also the possibility of contributing to the generation of wear particles is high.
  • the lattice constant of a metal increases, impurities easily dissolve, so the lattice constant of the electrode material is the lattice constant (about 3.3% by weight in Table 1) of P metal (approximately 3.
  • the lattice constant a is preferably set in the range of 3.80 A to 3.92 A, and is set in the range of 3.87 A to 3.92 A. Is more preferable. Furthermore, even when another metal element is added to the Pt ⁇ Rh-based metal, it can be used as a suitable electrode material by setting the lattice constant a in the range of 3.80 A to 3.92 A. .
  • FIG. 14 is a graph showing the lattice constant with respect to the Rh content (% by weight) of the Pt ⁇ Rh metal according to the present invention.
  • the lattice constant a obtained by the XRD analysis shown in Fig. 13 is plotted against the Rh content (Weight Percent of Rh).
  • the lattice constant a is related to the Rh content. Is approximately derived.
  • the linear function shown by the solid line is a fitting function for the plotted data, and is optimized by the least square method.
  • the upper limit value of the lattice constant obtained from the error range of the experimental value is indicated by a one-dot chain line linear function, and the lower limit value is indicated by a two-dot chain line linear function.
  • the Rh content is weight%
  • the a-X relational expression indicating the relationship between the Rh content and the lattice constant a is expressed as follows.
  • a suitable electrode material can be obtained by setting the lattice constant a within a desired range. If the Rh content is adjusted or selected using the above a—X relational expression, the lattice constant of the Pt ⁇ Rh-based metal according to the present invention can be set within a desired range. Obtainable. Therefore, using this electrode material, a highly durable plasma generating electrode can be easily manufactured.
  • FIG. 15 is a phase diagram of a P t—R h alloy which is an electrode material according to the present invention.
  • Ordinate Temperature (° C)
  • the horizontal axis represents the amount of Rh with respect to P t (wt. / 0)
  • curve A solid phase line
  • curve B the liquidus
  • the curve C shows the solubility line Yes.
  • This state diagram is based on the data described in THE PGM DATABASE "http://www.platinunimetalsreview.com/jnipgm/index.js non-patent document 2).
  • t And Rh are in a homogeneous melt state, and between curve A and curve B, the liquid and solid phases are mixed. The state on the low temperature side.
  • the liquidus and solidus lines show the bulk melting point of Pt metal (1 773.5 ° C) and the bulk melting point of Rh metal (1 963 ° C) over the entire content. It is in the range. It is not common for the melting point of a binary alloy to be completely within the range of the melting points of two metal crystals. In a binary alloy, if the compounding ratio is within a predetermined range, the melting point of two metals It often falls below the melting point of the crystal. For example, Au-Ni alloy, Ti-Zr alloy, Cr-Mo alloy, Pb-Sn alloy, Ag-Sr alloy and the like can be mentioned.
  • the melting point is about 1820 ° C. and 10 wt. /. Is about 1850 ° C, 20% by weight is about 1900 ° C to 1903 ° C, 30% by weight is about 1930 ° C to 1 933 ° C, and 40% by weight is about 195 3 ° C. Without dropping below the bulk melting point, the melting point of the alloy rises as the Rh content increases and approaches the melting point of the Rh metal.
  • FIG. 16 is a table showing the melting points of the Pt ⁇ Rh metal and other metals and alloys according to the present invention.
  • spark wear is one of the causes of the generation of wear material particles, and this spark wear is caused by an explosion phenomenon on the discharge surface during plasma generation.
  • This spark wear tends to be caused when a high melting point electrode material (W, Mo, etc .: see Fig. 16) is used, so the melting point is relatively low and the electrode tip is soft when plasma is generated. It is considered preferable to be deceived.
  • the Pt—Rh alloy according to the present invention has excellent oxidation resistance, and the melting point can be set within an appropriate range by selecting the Rh content. When the electrode material is in the range of the melting point of Pt metal (1773.
  • the temperature is set in the range of 3 ° C to 1953 ° C, and it is optimal from the range of 1850 ° C to 1933 ° C.
  • the melting point of the P t—W alloy is 1870 ° C., which is within the range of the preferable melting point 1 768 ° C. to 1963 ° C. described above.
  • remarkable electrode deformation was observed due to wear and melting. This is considered to be due to the low acid resistance of the P t—W alloy, indicating that the P t—W alloy is inappropriate for use as an electrode material for plasma generating electrodes. Yes.
  • the melting point of the Pt ⁇ Rh metal is described so as to be uniquely determined according to the weight ratio of Rh.
  • the same melting point is not always measured with respect to the weight ratio of Rh, and has a certain distribution depending on the preparation conditions of the alloy and the amount of impurities.
  • the inventors Based on the measured melting point of Pt * Rh metal, the inventors reflect the above melting point distribution, and the melting point T (° C) is easily derived from the Rh weight ratio. An approximate linear function that can be obtained is obtained.
  • Fig. 17 is a graph plotting the melting point of the P t ⁇ R h group metal according to the present invention against the weight ratio of R h (X wt%).
  • T—X relational expression approximately derived from these data is expressed as follows.
  • the melting point T (° C) of the P t 'Rh metal can be set within a predetermined temperature range by adjusting the weight ratio of Rh.
  • the Pt ⁇ Rh-based metal according to the present invention is not linear with respect to the weight ratio of the Rh weight ratio.
  • the melting point temperature rises with a relatively large slope with respect to the weight ratio.
  • the second T ⁇ X relational expression is approximately derived by fitting a linear function to data in which the weight ratio of R h is 0 wt% to 30 wt%.
  • Rh is 0 wt% to 30 wt%. In the range up to / 0, it shows good agreement with the linear function Taking into account the upper limit (one-dot chain line) and the lower limit (two-dot chain line), the second T-X relation is expressed by the following equation. .
  • the weight ratio of Rh is adjusted in the range of 0 ⁇ 30, and the melting point T (° C) is more reliably set within the predetermined temperature range. be able to.
  • FIG. 19 is a graph plotting the density p of the P t ⁇ Rh metal according to the present invention against the weight ratio of Rh (X wt%). This is a plot of measured density p of P t ⁇ Rh metals with different weight ratios of Rh. By using a linear function, the trend of density p (g cm 3 ) with respect to X weight% was derived approximately. ing.
  • the Pt ⁇ Rh metal according to the present invention is used for an electrode for plasma generation, it becomes difficult to set the electrical characteristics of the electrode to a predetermined value when the density p is greater than 21.45 g / cm 3. I know it is in a trend. This is thought to be due to the fact that the impurity content tends to increase with increasing density.
  • the density p is less than 1 2. 41 g Z c m 3 , in and. Or Burazuma when generating electrode formation, the discharge surface tend to pore formation, one of the factors that increases the occurrence of wear particles There is a possibility. Therefore, it is preferable to set the density p of the Pt ⁇ Rh-based metal in the range of 12.41 gZ cm 3 to 2'l. 45 gZ cm 3 . In addition to providing properties, it is possible to reduce the contamination of impurities and wear particles in the plasma.
  • the p ⁇ X relational expression is derived from the fitting to the actual measurement value, and the upper limit value (dashed line) and the lower limit value (2 Based on the dotted line), ⁇
  • the density p can be set within a predetermined density range by adjusting the weight ratio of R h. That is, the density of the Pt′Rh metal according to the present invention can be easily set within the above-described preferred density range (12.41 g / cm 3 to 21.45 g / cm 3 ).
  • FIG. 20 is a graph plotting the Vickers hardness HV of the Pt ⁇ Rh-based metal according to the present invention against the weight ratio (% by weight) of Rh. This is a plot of measured Vickers hardness HV of P t ⁇ Rh metals with different Rh weight ratios.
  • the Vickers hardness HV increases almost linearly, and the X weight of the Pickers hardness HV (Hv) using a linear function.
  • the trend for / 0 is approximately derived.
  • a Pt ⁇ Rh-based metal is used for a plasma generating electrode, if the Vickers hardness HV exceeds 13 OHv, the discharge surface becomes brittle, and it becomes difficult to process the plasma generating electrode into a predetermined shape. The generation of wear particles increases.
  • the Vickers hardness HV is less than 5 OHv, the durability is clearly reduced. That is, based on the electrode performance of the plasma generating electrode, the Pt ⁇ Rh-based metal is preferably set as an electrode material in a range of Vickers hardness HV from 5 OHv to I 30 Hv.
  • the picker hardness HV can be set within a predetermined range, and suitable workability is imparted to the electrode material, and generation of wear particles during plasma generation is suppressed. be able to.
  • FIG. 21 is a schematic configuration diagram of a pen jet type plasma processing apparatus having a tubular rod electrode (hereinafter referred to as “tubular electrode 44”) according to the present invention.
  • the tubular electrode 44 is provided with a gas introduction port 50, and the working gas 28 circulates through the tubular electrode 44 from the gas introduction port 50 and is supplied to the plasma generator 4a. It is done.
  • a high voltage pulse is applied between the electrode tip surface 46a of the tubular electrode tip 46 and the nozzle-like electrode 16 to generate arc discharge and generate plasma.
  • the second gas inlet 56 is provided, and various substances can be supplied as the working gas in accordance with the same gas or purpose as the working gas 28.
  • the electrode for plasma generation according to the present invention includes an electrode tip surface 46a of the tubular electrode 44 and the vicinity thereof.
  • the discharge surface is made of Pt ⁇ Rh-based metal, and electrode wear and wear material particles are suppressed.
  • FIG. 22 is a schematic configuration diagram of the plasma generating unit 4 a when the plasma generating electrode according to the present invention is a grinding arc type electrode 60.
  • the end-spread electrodes 60 a and 60 b arranged in the circulating working gas 28 are connected to the current lines 62 a and 62 b, and a high voltage pulse is applied between the electrodes.
  • Plasma P is generated by applying arc to cause arc discharge.
  • a mixture of strongly ionized plasma (also known as “column”) or streamer that forms the current path 61 of arc discharge and weakly ionized plasma 65 5 (plasma plume) that hardly flows current. appear.
  • the discharge surfaces 63a and 63b of the electrodes 60a and 6Ob are made of Pt ⁇ Rh-based metal to suppress electrode wear of the grinding arc electrode 60 and reduce the generation of wear material particles. It can be
  • the cross-sectional diameters of the electrodes 60a and 60b made of Pt-Rh metal are about 1.6 mm (cross-sectional area: about 2 mm 2 ).
  • the pulse frequency is about 30 kHz
  • the pulse width is about 3 ns
  • the flow rate of the supplied working gas is about 40 L, 'min
  • the supply power is set to the following value:
  • the average power is 300W (15 OW mm 2) or less
  • the maximum applied voltage is about 7 k V
  • the maximum peak current 3A (1. 5A. Mm 2) is preferably set to below.
  • the unit area is the unit cross-sectional area of the electrodes 60a and 60b.
  • the discharge area is large, and the supplied power can be set to a relatively large value.
  • a large amount of working gas can be circulated to generate plasma. Therefore, if the density of the average power is set to 15 OWZ'mm 2 or less, the amount of plasma generated can be appropriately adjusted according to the cross-sectional area.
  • FIG. 23 is a schematic configuration diagram in the case where the plasma generating electrode 0 according to the present invention includes saw-toothed electrodes 72 a and 72 b.
  • This plasma generating electrode 70 has both outer sides
  • the sawtooth electrodes 7 2 a and 7 2 b and the earth-type electrode 74 are connected to the power sources 76 6 a and 76 b.
  • Each of the sawtooth electrodes 7 2 a and 7 2 b is provided with a plurality of sharp projections 7 7 a and 7 7 b, and by concentrating the electric field on these sharp projections 7 7 a and 7 7 b Arc discharge easily occurs and plasma P is generated.
  • the plasma generating electrode according to the present invention has excellent oxidation resistance and has a suitable melting point because at least the discharge surface is formed of a Pt ⁇ Rh-based metal, so that plasma generated by various discharges Electrode wear and generation of wear material particles during generation can be suppressed to a very small amount. Therefore, it is possible to provide a plasma generation apparatus that generates a high-purity plasma using the plasma generation electrode. Furthermore, it is possible to suppress the adhesion of impurities by the plasma generation apparatus and realize a uniform plasma treatment of the surface of the workpiece.
  • the arc plasma generated by the plasma generation apparatus according to the present invention is a plasma that can be generated under a pressure of about atmospheric pressure, and is used for various processes and surface treatments.

Abstract

A long life plasma generation electrode in which emission of particles of worn materials is significantly reduced when plasma is generated by discharge and wear-out of the electrode is reduced extremely, and a plasma generation apparatus and a plasma processing system. In a plasma generation electrode of a plasma generation apparatus (7) for generating plasma P of a supply gas by discharge, at least the discharge surface is formed of an electrode material of Pt Rh based metal represented by Pt1-YRhY (0≤Y<1). The plasma generation apparatus (7) generates plasma using this plasma generation electrode, and a plasma processing system (2) performs plasma processing of the surface of an article to be processed using this plasma generation apparatus.

Description

プラズマ生成用 P t ' R h系電極、 プラズマ生成装置及びプラズマ処理装置 (技術分野）  Pt'Rh electrode for plasma generation, plasma generator and plasma processing equipment (technical field)
本発明は、 プラズマ生成用電極に関し、 更に詳細には、 放電によって供給ガス のプラズマを発生させるプラズマ一生成用電極、 この電極を用いてプラズマを生成 するブラズマ生成装置及び被処理物表面をプラズマ処理するブラズマ処理装置に 関する。 田  The present invention relates to a plasma generating electrode, and more specifically, a plasma generating electrode that generates plasma of a supply gas by discharge, a plasma generating device that generates plasma using this electrode, and a surface of an object to be processed. Related to plasma processing equipment. Rice field
(背景技術） (Background technology)
プラズマ生成装置は、 電極形状、 印加電圧の特性、 原料物質やその供給形態等 に応じて、 放電により発生するプラズマの特性が設定され、 プラズマを発生させ る放電現象としては、 グロ一放電、 異常グロ一放電、 Radio Frequency (R F ) 放電又はコロナ放電等がある。 例えば、 アーク放電により生成されるアークプラ ズマは、 射出方向に外周から気流ゃ水冷壁などによって冷却することにより安定 ィ匕される力 ら、 制御性に優れると共に、 高温でエネルギー密度が高いことから、 各種の加工や表面処理等に用いられている。 更に、 アーク放電は、 真空中から大 気圧以上の幅広い圧力下において生起される放電であり、 種々の原料ガス （以下 「作動ガス」 と呼ぶ） を容易にプラズマ化することができ、 原料ガスに応じて所 望の表面処理を行うことが可能である。 半導体製品、 金属製品、 ガラス製品、 加 ェ用部材等の被処理物表面をブラズマ処理することにより、 原料ガスや供給電力 に応じて表面加工 （エッチング、 表面コーティングなど） 、 表面改質 （濡れ性改 善、 接着性改善、 生体融和性改善） 、 洗浄及びデスミア処理、 粉体合成、 薄膜形 成等を行うことが可能である。  In the plasma generator, the characteristics of the plasma generated by the discharge are set according to the electrode shape, applied voltage characteristics, raw material and its supply form, etc. The discharge phenomenon that generates plasma is a glow discharge, abnormal Glow discharge, radio frequency (RF) discharge or corona discharge. For example, arc plasma generated by arc discharge has excellent controllability and high energy density at high temperatures because it is stabilized by cooling the airflow from the outer periphery in the injection direction with water cooling walls. It is used for various processing and surface treatment. In addition, arc discharge is a discharge that occurs in a wide range of pressures from vacuum to atmospheric pressure. Various source gases (hereinafter referred to as “working gases”) can be easily turned into plasma, The desired surface treatment can be performed accordingly. Surface processing (etching, surface coating, etc.) and surface modification (wetting properties) according to source gas and power supply by processing the surface of workpieces such as semiconductor products, metal products, glass products, processing parts, etc. Improvement, adhesion improvement, biocompatibility improvement), cleaning and desmear treatment, powder synthesis, thin film formation, etc. are possible.
前記プラズマ生成用電極には、 高融点で小さな仕事関数を有する金属が使用さ れ、 タングステン （W) やモリブデン （M o ) などが電極材料として用いられて いる。 特開平 1 0— 2 9 6 4 4 5号公報 （特許文献 1 ) 及び特開平 1 1一 2 8 5 8 3 4号公報 （特許文献 2 ) に記載されるプラズマアークトーチは、 図 2 4に示 すように、 タングステン製の棒状電極 108が内装され、 その棒状電極 108の 先端外周にノズル状電極 1 1 6が配設されている。 即ち、 棒状電極 108とノズ ル状電極 1 16の間に電圧を印加してプラズマを発生させて、 ノズル状電極 1 1 6の射出口 1 16 aからプラズマ Pをジヱット状に射出するように構成されてい る。 For the plasma generating electrode, a metal having a high melting point and a small work function is used, and tungsten (W), molybdenum (Mo), or the like is used as an electrode material. The plasma arc torch described in Japanese Patent Application Laid-Open No. 10-29 96 4 45 (Patent Document 1) and Japanese Patent Application Laid-Open No. 11 1 2 8 5 8 3 4 (Patent Document 2) is shown in FIG. Indication In this way, a rod-shaped electrode 108 made of tungsten is internally provided, and a nozzle-shaped electrode 116 is disposed on the outer periphery of the tip of the rod-shaped electrode 108. That is, a voltage is applied between the rod-shaped electrode 108 and the nozzle-shaped electrode 1 16 to generate plasma, and the plasma P is ejected in a jet shape from the ejection port 1 16 a of the nozzle-shaped electrode 1 1 6. It has been done.
上述のように、 図 24は従来のプラズマ生成用電極におけるプラズマ生成の模 式図であり、 プラズマ生成用電極として特許文献 1及び 2 記載されるタンダス テン製の棒状電極 108を用いた場合、 電極先端面 108 aの電極点 108 bか ら損耗材料粒子 109が放出される。 特開 2004— 358623公報 （特許文 献 3) に記載される放電加工技術では、 上述のような電極損耗を低減化するため 、 Wや Moに銅 （Cu) 又は銀 （Ag) を配合した合金が放電加工用の電極材料 として用いられ、 電極損耗の低減化が図られているが、 損耗の大幅な抑制は実現 されていなかった。  As described above, FIG. 24 is a schematic diagram of plasma generation in the conventional plasma generation electrode. When the Tandasten rod-shaped electrode 108 described in Patent Documents 1 and 2 is used as the plasma generation electrode, the electrode The wear material particles 109 are discharged from the electrode point 108 b on the front end surface 108 a. In the electric discharge machining technique described in JP 2004-358623 A (Patent Document 3), an alloy in which copper (Cu) or silver (Ag) is blended with W or Mo is used to reduce electrode wear as described above. Has been used as an electrode material for electric discharge machining, and electrode wear has been reduced, but the wear has not been significantly suppressed.
また、 アークプラズマの生成装置に用いられるプラズマ生成用電極としては、 グラインデイングアーク型電極があり、 A. Czemichowski： Gliding Arc.  In addition, as an electrode for plasma generation used in an arc plasma generator, there is a grinding arc type electrode. A. Czemichowski: Gliding Arc.
Applications to engineering and environment control, Pure ana Applied Chemical, Vol. 666 (1 994) p p. 1 301— 1 310 (非特許文献 1 ) などに記載されている。 グラインデイングアーク型電極では、 大気圧又はその 近傍の圧力下において、 アーク放電を生起してアークブラズマを生成することが でき、 より長寿命で安定して高純度のアークプラズマを生成するグラインディン グアーク型電極用材料が要望されていた。  Applications to engineering and environment control, Pure ana Applied Chemical, Vol. 666 (1 994) pp. 1 301—1 310 (Non-patent Document 1). Grinding arc type electrodes can generate arc plasma by generating an arc discharge at or near atmospheric pressure, creating a long-life, stable, high-purity arc plasma. There has been a demand for a mold electrode material.
尚、 後述するように、 本件明細書では、 "THE PGM DATABASE"  As will be described later, in this specification, “THE PGM DATABASE”
http://w w. platinummetalsreview. com/ jmpgm/ index, jsp (非特^ :文献 2 ) に 己 載されるデータを引用している。 http://www.platinummetalsreview.com/jmpgm/index, jsp (Non-patent document : Reference 2).
[特許文献 1] 特開平 10— 296445号公報  [Patent Document 1] Japanese Patent Laid-Open No. 10-296445
[特許文献 2] 特開平 1 1一 285834号公報  [Patent Document 2] Japanese Patent Application Laid-Open No. 1 1-285834
[特許文献 3 ] 特開 2004— 358623公報  [Patent Document 3] Japanese Patent Application Laid-Open No. 2004-358623
[非特許文献 1 J A. Czemichowski： Gliding Arc. Applications to  [Non-Patent Document 1 J A. Czemichowski: Gliding Arc. Applications to
engineering and environment control, Pure and Applied Chemical, Vol. 66 (1994) p. 1301-1310 engineering and environment control, Pure and Applied Chemical, Vol. 66 (1994) p. 1301-1310
[非特許文献 2 ] "THE PGM DATABASE" http： //www. plat inumraetal srevi ew.  [Non-Patent Document 2] "THE PGM DATABASE" http: // www. Plat inumraetal srevi ew.
com/ jmpgm/index. jsp (発明の開示）  com / jmpgm / index. jsp (disclosure of the invention)
前述のように、 図 2 4に示すタングステン製の棒状電極 1 0 8が用いられた場 合、 電極点 1 0 8 bからプラズマ Pと共に損耗材料粒子 1 0 9が放出される。 こ れは、 電極点 1 0 8 bの爆発現象による火花損耗や酸化した電極先端面 1 0 8 a が剥離する酸化損耗によって引起される。 従って、 従来のプラズマ生成用電極を 用レ、てブラズマ処理を行った場合、 被処理物 1 2 2の表面に多量の損耗材料粒子 1 0 9が付着し、 高精度の表面加工や均一な表面処理等を行うことができなかつ た。 なお、 損耗材料粒子の放出を伴わず、 電極材料が昇華 '蒸発して減少 '損耗 する現象として、 ジュール熱やプラズマ放射による表面加熱による蒸発損耗があ る。  As described above, when the tungsten rod-like electrode 10 8 shown in FIG. 24 is used, the wear material particles 10 9 are emitted together with the plasma P from the electrode point 10 8 b. This is caused by the spark wear due to the explosion phenomenon of the electrode point 10 8 b and the oxidation wear that peels off the oxidized electrode front end face 10 8 a. Therefore, when plasma treatment is performed using a conventional plasma generating electrode, a large amount of wear material particles 1 0 9 adhere to the surface of the workpiece 1 2 2, resulting in high-precision surface processing and a uniform surface. Processing could not be performed. As a phenomenon in which the electrode material sublimates, evaporates and decreases, without being accompanied by the release of wear material particles, there is evaporation wear due to surface heating by Joule heat or plasma radiation.
図 2 5は、 従来の W又は C uからなる棒状電極 1 0 8を用いてアークプラズマ を発生させた場合の電極先端の拡大写真図である。 （2 5 A) 上段及び中段の拡 大写真図に示すように、 タングステン （W) 製の棒状電極における先端周縁には 、 酸ィヒにより剥離仕懸かった酸化タングステンが形成されており、 多量の損耗材 料粒子が棒状電極先端から放出されたことが分かる。 （ 2 5 A) 下段に示めす電 子顕微鏡像からは、 棒状電極先端面が酸化により脆くなり、 剥離し易い状態にな つていることが分かる。 即ち、 高融点の電極材料 （Wの融点： 3 7 0 4 °C) を用 いても、 金属材料が酸化し易い場合、 プラズマ生成用電極材料として適しておら ず、 特許文献 1及び 2に記載されるようなプラズマトーチを被処理物の加工に用 いた場合、 多量の不純物を付着させていた。  FIG. 25 is an enlarged photograph of the electrode tip when arc plasma is generated using a conventional rod-shaped electrode 108 made of W or Cu. (25 A) As shown in the enlarged photographs of the upper and middle stages, tungsten oxide that has been peeled off by acid is formed on the periphery of the tip of the rod-shaped electrode made of tungsten (W). It can be seen that the wear material particles were released from the tip of the rod-shaped electrode. (25 A) From the electron microscope image shown in the lower part, it can be seen that the tip of the rod-shaped electrode becomes brittle due to oxidation and is easily peeled off. That is, even if a high melting point electrode material (melting point of W: 3704 ° C) is used, if the metal material is easily oxidized, it is not suitable as an electrode material for plasma generation, and is described in Patent Documents 1 and 2. When a plasma torch like this is used to process a workpiece, a large amount of impurities are adhered.
更に、 図 2 5の （2 5 B ) は、 比較的融点の低い銅製の棒状電極 （C uの融点 ： 1 0 8 4 °C) を用いて、 アークプラズマを発生させた場合の棒状電極先端の状 態を示している。 （2 5 B ) 上段の拡大写真図では、 銅製の棒状電極先端の損耗 が激しく、 多量に損耗材料粒子が放出されていることが分かる。 （2 5 B ) 中段 に示した拡大写真図には、 数 1 0 i m〜l 0 0 m程度以上の大きなクレーター  Furthermore, (25 B) in Fig. 25 shows the tip of the rod-shaped electrode when arc plasma is generated using a copper rod-shaped electrode (Cu melting point: 1084 ° C) with a relatively low melting point. This shows the state. (25 B) In the enlarged photograph on the top, it can be seen that the tip of the copper rod electrode is severely worn, and a large amount of wear material particles are released. (2 5 B) The enlarged photograph shown in the middle section shows a large crater of about 10 0 m to l 0 0 m or more.
3 状の損耗部が形成されている。 更に、 （2 5 B ) 下段の電子顕微鏡像には、 1 0 U m程度若しくはそれ以下の微細な損耗部が形成されており、 （ 2 5 B ) 中段及 び下段に示した拡大写真図から、 大小様々な損耗材料粒子が棒状電極先端から放 出されていることが分かる。 Three A shaped wear part is formed. Furthermore, (2 5 B) The lower part of the electron microscope image has a fine wear part of about 10 Um or less. (2 5 B) From the enlarged photograph shown in the middle and lower parts It can be seen that wear material particles of various sizes are released from the tip of the rod-shaped electrode.
Wや C uからなる棒状電極を用レ、たブラズマ生成試験の結果は、 特許文献 3に おいて、 Wと C uからなる合金を電極材料として用いた場合に、 アーク放電によ' る電極損耗の効果的な低減ィヒが為されなかったことを追認する結果となっている 。 即ち、 W、 C u及びこれらの合金がアーク放電用電極に好適な電極材料ではな いことを示している。 従って、 従来の電極材料から形成されるアーク放電用電極 に用いてアークプラズマ生成し、 このアークプラズマにより表面加工や表面改質 等を行った場合、 損耗材料粒子が放出されて被処理物表面に付着し、 損耗材料粒 子が不純物としてコーティング膜中に混入するため、 均一な表面処理を行うこと ができなかった。  The results of the plasma generation test using a rod-shaped electrode made of W or Cu are shown in Patent Document 3 when an alloy made of W and Cu is used as the electrode material. This confirms that no effective reduction of wear was made. That is, it is shown that W, Cu and their alloys are not suitable electrode materials for arc discharge electrodes. Therefore, when arc plasma is generated using an arc discharge electrode formed from a conventional electrode material, and surface processing or surface modification is performed by this arc plasma, wear material particles are released and are applied to the surface of the workpiece. Since the adhering and wearable material particles are mixed into the coating film as impurities, uniform surface treatment could not be performed.
図 2 5には、 アークプラズマの発生に用いられる従来のプラズマ生成用電極に 関する結果を示したが、 グロ一放電、 異常グロ一放電、 R F放電又はコロナ放電 によってプラズマを発生させる場合においても同様の結果が得られる。 即ち、 プ ラズマ発生時に電極表面は、 酸化や蒸発などが引起され得る温度に達し、 従来の プラズマ生成用電極を用いた場合、 電極損耗により損耗材料粒子が発生し、 所望 のプラズマ処理を行うことが困難であった。 特に、 異常グロ一放電では、 電極が 高温になるため、 耐熱性の高いプラズマ生成用電極が求められていた。  Fig. 25 shows the results for the conventional plasma generating electrode used to generate arc plasma, but the same applies when plasma is generated by glow discharge, abnormal glow discharge, RF discharge or corona discharge. Result is obtained. That is, when the plasma is generated, the electrode surface reaches a temperature at which oxidation or evaporation can be caused, and when a conventional plasma generation electrode is used, wear material particles are generated due to electrode wear, and a desired plasma treatment is performed. It was difficult. In particular, in abnormal glow discharge, since the electrode becomes hot, an electrode for plasma generation with high heat resistance has been demanded.
本発明の目的は、 放電によりプラズマを発生させた場合に損耗材料粒子の放出 が大幅に低減化され、 電極損耗が極めて少なく、 長寿命のプラズマ生成用電極及 びブラズマ生成装置を提供すると同時に、 被処理物表面に高精度な表面加工や所 望の物性を付与する表面改質等を行うプラズマ処理装置を提供することである。 本発明は、 上記課題を解決するためになされたものであり、 本発明の第 1の形 態は、 放電によつて供給ガスのプラズマを発生させるプラズマ生成装置のプラズ マ生成用電極であって、 このプラズマ生成用電極の少なくとも放電表面が P t！ -Y R h Y ( 0≤Y < 1 ) で表される P t . R h系金属の電極材料から形成される プラズマ生成用電極である。 本発明の第 2の形態は、 第 1の形態において、 前記 P t ' Rh系金属の格子定 数 aが 3. 80A〜3. 92 Aの範囲にあるプラズマ生成用電極である。 The object of the present invention is to provide an electrode for plasma generation and a plasma generation apparatus with a long life, in which discharge of wear material particles is greatly reduced when plasma is generated by discharge, electrode wear is extremely low, It is an object of the present invention to provide a plasma processing apparatus that performs high-precision surface processing on a surface of an object to be processed and surface modification that imparts desired physical properties. The present invention has been made to solve the above problems, and a first embodiment of the present invention is a plasma generation electrode of a plasma generation apparatus that generates plasma of a supply gas by discharge. At least the discharge surface of this plasma generating electrode is Pt! - a Y R h Y (0≤Y <1 ) represented by P t plasma generation electrode formed from R h based metallic electrode material.. The second aspect of the present invention is the plasma generating electrode according to the first aspect, wherein the lattice constant a of the P t 'Rh-based metal is in the range of 3.80 A to 3.92 A.
本発明の第 3の形態は、 第 1又は第 2の形態において、 前記 P t ' Rh系金属 の融点が 1 773° (〜 1 966°Cの範囲にあるプラズマ生成用電極である。 本発明の第 4の形態は、 第 1〜第 3の形態のいずれかにおいて、 前記 P t · R h系金属の結晶構造が面心立方格子 （FCC) 構造であるプラズマ生成用電極で める。  A third mode of the present invention is the plasma generating electrode according to the first or second mode, wherein the melting point of the Pt′Rh-based metal is in the range of 1 773 ° (up to 1966 ° C.). The fourth embodiment is a plasma generation electrode according to any one of the first to third embodiments, wherein the crystal structure of the Pt · Rh-based metal is a face-centered cubic lattice (FCC) structure.
本発明の第 5の形態は、 第 1〜第 4の形態のいずれかにおいて、 前記 P t - R h系金属の結晶粒径が 0. 5 μ π！〜 100 mの範囲にあるプラズマ生成用電極 である。  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the crystal grain size of the Pt—Rh-based metal is 0.5 μπ! It is an electrode for plasma generation in the range of ~ 100 m.
本発明の第 6の形態は、 第 1〜第 5の形態のいずれかにおいて、 前記 P t · R h系金属の密度 pが 1' 2. 41 g ,' cm3〜21. 45 g/ c m3の範囲にある プラズマ生成用電極である。 According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the density p of the Pt · Rh-based metal is 1 '2.41 g,' cm 3 to 21.45 g / cm. This is a plasma generating electrode in the range of 3 .
本発明の第 7の形態は、 第 1〜第 6の形態のいずれかにおいて、 前記 P t - R h系金属のビッカース硬度 HVが 5 OHv〜l 30 H vの範囲にあるプラズマ生 成用電極である。  A seventh aspect of the present invention is the plasma generating electrode according to any one of the first to sixth aspects, wherein the Pt-Rh-based metal has a Vickers hardness HV in the range of 5 OHv to l 30 Hv. It is.
本発明の第 8の形態は、 第 1〜第 7の形態のいずれかにおいて、 前記 P t - R h系金属に占める Rhの重量比率を X重量％とするとき、 前記 P t ' Rh系金属 の格子定数 a (A) と前記 重量％の a— X関係式が  According to an eighth aspect of the present invention, in any one of the first to seventh aspects, when the weight ratio of Rh to the Pt-Rh-based metal is X wt%, the Pt'Rh-based metal The lattice constant a (A) of the above and the a%
a =- 0. 001 1 3 X+ 3. 908±0. 02  a =-0. 001 1 3 X + 3. 908 ± 0.02
で表され、 前記 R hの重量比率を調整して前記格子定数 aが設定されるプラズマ 生成用電極である。 The electrode for plasma generation, wherein the lattice constant a is set by adjusting the weight ratio of Rh.
本発明の第 9の形態は、 第 1〜第 8の形態のいずれかにおいて、.前記 P t - R h系金属に占める Rhの重量比率を X重量％とするとき、 前記 P t ' Rh系金属 の融点 T (°C) と前記 重量％の T一 X関係式が  According to a ninth aspect of the present invention, in any one of the first to eighth aspects, when the weight ratio of Rh in the Pt-Rh-based metal is X wt%, the Pt'Rh-based The melting point T (° C) of the metal and T
T =- 1. 4890X+ 1836. 3±70  T =-1. 4890X + 1836. 3 ± 70
で表される又は前記 X重量％が 0≤ X≤ 30の範囲にあるとき Τ一 X関係式が Τ = - 5. 255 Χ+ 1785. 3± 15 で表され、 前記 R hの重量比率を調整して前記融点 Tが設定されるプラズマ生成 用電極である。 . Or when X weight% is in the range of 0≤ X≤ 30 Τichi X relation is Τ =-5. 255 Χ + 1785. 3 ± 15 An electrode for plasma generation in which the melting point T is set by adjusting the weight ratio of the Rh. .
本発明の第 10の形態は、 第 1〜第 9の形態のいずれかにおいて、 前記 P t . Rh系金属に占める Rhの重量比率が 重量％であるとき、 前記 P t * Rh系金 属の密度 p (g/ cm3) と前記 重量％の p _X関係式が According to a tenth aspect of the present invention, in any one of the first to ninth aspects, when the weight ratio of Rh to the Pt.Rh-based metal is wt%, the Pt * Rh-based metal The density p (g / cm 3 ) and the weight%
=- 0. 08401 X+ 20. 87±0. 6  =-0. 08401 X + 20. 87 ± 0.6
で表され、 前記 Rhの重量比率を調整して前記密度 pが設定されるプラズマ生成 用電極である。 In the plasma generating electrode, the density p is set by adjusting the weight ratio of Rh.
本発明の第 1 1の形態は、 第 1〜第 10の形態のいずれかにおいて、 前記 P t · Rh系金属に占める Rhの重量比率が 重量％であるとき、 前記 P t · Rh系 金属のビッカース硬度 HV (Hv) と前記 X重量％の HV— X関係式が  According to a first aspect of the present invention, in any one of the first to tenth aspects, when the weight ratio of Rh to the Pt · Rh-based metal is wt%, the Pt · Rh-based metal Vickers hardness HV (Hv) and X weight% of HV— X
HV = - 2. 76 X + 51. 85± 15  HV =-2.76 X + 51. 85 ± 15
で表され、 前記 R hの重量比率を調整して前記ビッカース硬度 H Vが設定される プラズマ生成用電極である。 An electrode for plasma generation in which the Vickers hardness HV is set by adjusting the weight ratio of Rh.
本発明の第 12の形態は、 第 1〜第 1 1の形態のいずれかにおいて、 前記 P t • 1 1 系金属に占める1^11の重量比率が0重量％〜40重量％の範囲に設定され るプラズマ生成用電極である。  In a twelfth aspect of the present invention, in any one of the first to first aspects, a weight ratio of 1 ^ 11 occupying the P t • 1 1 group metal is set in a range of 0 wt% to 40 wt%. This is an electrode for plasma generation.
本発明の第 1 3の形態は、 第 1〜第 12の形態のいずれかにおいて、 前記放電 が生起される電極が高電界電極 （=高電圧電極；絶対値のより大きな電圧が印加 されている電極） と低電界電極 （=低電圧電極；絶対値のより小さな電圧が印加 されている電極、 例えば接地電極） を対向させて構成され、 前記高電界電極の前 記対向面に前記放電表面を配置し、 少なくとも前記高電界電極の放電表面が前記 電極材料から形成されるプラズマ生成用電極である。 .  According to a first aspect of the present invention, in any one of the first to twelfth aspects, the electrode in which the discharge is generated is a high electric field electrode (= high voltage electrode; a voltage having a larger absolute value is applied). Electrode) and a low electric field electrode (= low voltage electrode; an electrode to which a voltage having a smaller absolute value is applied, for example, a ground electrode) are opposed to each other, and the discharge surface is disposed on the opposite surface of the high electric field electrode. The electrode for plasma generation is arranged and at least a discharge surface of the high electric field electrode is formed from the electrode material. .
本発明の第 14の形態は、 第 1 3の形態において、 前記高電界電極が棒状電極 であり、 前記低電界電極がプラズマ射出口を有するノズル状電極であり、 前記電 極がペンジヱット型電極を構成する請求項 1 1に記載のプラズマ生成用電極。 本発明の第 15の形態は、 第 14の形態において、 前記棒状電極の少なくとも 先端部が前記電極材料から形成されるプラズマ生成用電極である。  According to a fourteenth aspect of the present invention, in the first aspect, the high electric field electrode is a rod-shaped electrode, the low electric field electrode is a nozzle-shaped electrode having a plasma injection port, and the electrode is a pendant electrode. The plasma generating electrode according to claim 11, which is configured. A fifteenth aspect of the present invention is the plasma generating electrode according to the fourteenth aspect, wherein at least the tip of the rod-shaped electrode is formed from the electrode material.
本発明の第 16の形態は、 第 13の形態において、 前記高電界電極が放電表面 側に 1つ以上の突起を有する突起型電極であるプラズマ生成用電極である。 In a sixteenth aspect of the present invention, in the thirteenth aspect, the high electric field electrode is a discharge surface. A plasma generating electrode which is a protruding electrode having one or more protrusions on the side.
本発明の第 17の形態は、 第 1〜 16の形態のいずれかのプラズマ生成用電極 を用いてプラズマを生成するプラズマ生成装置である。  A seventeenth aspect of the present invention is a plasma generation apparatus for generating plasma using the plasma generation electrode according to any one of the first to sixteenth aspects.
本発明の第 16の形態は、 第 1 5の形態のブラズマ生成装置により被処理物表 面をプラズマ処理するプラズマ処理装置である。  A sixteenth aspect of the present invention is a plasma processing apparatus for performing plasma processing on a surface of an object to be processed by the plasma generating apparatus according to the fifteenth aspect.
本発明の第 1の形態によれば、 プラズマを発生させるプラズマ生成用電極の少' なくとも放電表面が P t 1→R Y (0≤Y< 1) で表される P t · Rh系金属 の電極材料から形成されるから、 電極損耗を大幅に低減化して損耗材料粒子の放 出を極めて微量に抑制することができる。 前記 P t. ' Rh系金属は、 P t金属 （ 組成比 Yが Y = 0の場合） や P t— R h合金 （組成比 Yが 0く Y < 1の場合） か ら形成され、 前記 P t金属や P t— R h合金が結晶子を形成し、 この結晶子が多 結晶体金属を構成している。 本発明に係る P t— Rh合金が結晶子を形成してい ることは、 走査型イオン顕微鏡による観察により確かめられている。 従来のブラ ズマ生成用電極に用いられている Wなどの高融点電極材料に比べ、 本発明に係る P t · Rh系金属の融点は低く、 Wの融点が 3704°Cであるのに対して、 P t のバルタ金属の融点は 1 773。 5°C、 Rhのバルタ金属の融点は 1 960°C〜 1 966°Cである。 尚、 後述するように、 前記 P t · Rh系金属が P t— Rh合 金である場合、 Rh元素の含有比率は、 重量比率で示されており、 組成比 Yと重 量比率を示す X重量％は、 χ= 100 X 102. 9 X Υ ' {195. I X ( 1 - Υ) + 102. 9 ΧΥ} で表される関係を有しており、 P tの原子量 195. 1 、 Rhの原子量 102. 9を用いている。 従って、 組成比 Yは、 重量％を用い て、 Y= 195. 1 ΧΧ ·' {102. 9 Χ (100— Χ) + 195. I X X} で 表さ る。 According to the first aspect of the present invention, at least the discharge surface of the plasma generating electrode for generating plasma has a discharge surface represented by P t 1 → R Y (0≤Y <1). Therefore, it is possible to greatly reduce electrode wear and to suppress the release of wear material particles to a very small amount. The P t. 'Rh-based metal is formed from Pt metal (when the composition ratio Y is Y = 0) or Pt—Rh alloy (when the composition ratio Y is 0 and Y <1), Pt metal and Pt—Rh alloy form crystallites, and these crystallites constitute polycrystalline metals. The formation of crystallites in the Pt—Rh alloy according to the present invention has been confirmed by observation with a scanning ion microscope. Compared to conventional high melting point electrode materials such as W used for plasma generation electrodes, the melting point of the Pt · Rh-based metal according to the present invention is low, whereas the melting point of W is 3704 ° C. The melting point of Pt Balta metal is 1 773. The melting point of Balta metal at 5 ° C and Rh is 1 960 ° C to 1 966 ° C. As will be described later, when the Pt · Rh-based metal is a Pt-Rh alloy, the content ratio of the Rh element is indicated by the weight ratio, and the composition ratio Y and the weight ratio X are indicated. The weight% has the relationship represented by χ = 100 X 102.9 X Υ '{195. IX (1-Υ) + 102.9 ΧΥ}, and the atomic weight of P t 195. 1, Rh An atomic weight of 102.9 is used. Therefore, the composition ratio Y is expressed by Y = 195. 1 ΧΧ · '{102.9 Χ (100— Χ) + 195. IXX} using the weight%.
本発明者らは、 鋭意研究の結果、 耐酸化性がプラズマ生成用電極の損耗に対し て重要な要素であることを想到し、 P tや R hが優れた耐酸化性及び耐熱性を有 していることに着目して、 少なくとも前記放電表面が P t · Rh系金属から形成 されるプラズマ生成用電極 ( 「プラズマ生成用 P t ' Rh系電極」 とも呼ぶ） を 完成するに到った。 このプラズマ生成用電極は、 アーク放電、 グロ一放電、 異常 グ口一放電、 R F放電又はコロナ放電によるプラズマの生成に利用することがで き、 プラズマ発生時の電極損耗を抑制することができ、 異常グロ一放電のように 前記放電表面が高温になる程、 電極損耗抑制効果がより顕著になる。 更に、 本発 明に係るブラズマ生成用電極を用レ、れば、 損耗材料粒子の放出が極めて微量に抑 制されるから、 作動ガスをプラズマ化して原料物質粉体又は原料物質ガスを混入 させることにより、 プラズマ溶射、 熱プラズマ C VD法等により被処理物表面に 高純度のコ一ティング膜を形成することができる。 As a result of diligent research, the present inventors have conceived that oxidation resistance is an important factor for the wear of plasma generating electrodes, and that Pt and Rh have excellent oxidation resistance and heat resistance. As a result, we have completed a plasma generation electrode (also called “Pt'Rh electrode for plasma generation”) in which at least the discharge surface is made of a P t · Rh metal. . This electrode for plasma generation can be used for generation of plasma by arc discharge, glow discharge, abnormal outlet discharge, RF discharge or corona discharge. In addition, electrode wear at the time of plasma generation can be suppressed, and the electrode wear suppression effect becomes more prominent as the discharge surface becomes hot like abnormal glow discharge. Further, if the plasma generating electrode according to the present invention is used, the release of the wear material particles is suppressed to a very small amount, so that the working gas is made into plasma and mixed with the raw material powder or the raw material gas. As a result, a high-purity coating film can be formed on the surface of the object to be processed by plasma spraying, thermal plasma C VD method, or the like.
更に、 損耗材料粒子の放出が大幅に抑制されることにより、 薄膜加工 （例えば 、 ダイャモンド薄膜の微細加工 ·除去、 ダイャモンドライク力一ボン膜の微細加 ェ ·除去） では、 高精度に微細加工を行うことができる。 また、 被処理物が金属 材料である場合、 金属の溶解精練や熱分解、 金属酸化物の還元などに本発明に係 るブラズマ生成用電極によって生成されたブラズマを利用すれば、 被処理物への 損耗材料粒子の混入が防止される。 更に、 所望の作動ガスをプラズマ化して被処 理物表面に照射すれば、 損耗材料粒子の放出が抑制されることにより、 均一な表 面改質 （濡れ性改善、 接着性改善、 生体融和性改善など） 、 洗浄及びデスミア処 理等を高効率に行うことができる。  Furthermore, since the release of wear material particles is greatly suppressed, thin film processing (for example, microfabrication / removal of diamond thin film, micro-etching / removal of diamond-like force film) is performed with high precision. Processing can be performed. In addition, when the object to be processed is a metal material, if the plasma generated by the electrode for generating plasma according to the present invention is used for dissolving and scouring metal, thermal decomposition, reduction of metal oxide, etc., the material to be processed It is possible to prevent contamination of wear material particles. Furthermore, if the desired working gas is turned into plasma and irradiated onto the surface of the object to be processed, the release of wear material particles is suppressed, resulting in uniform surface modification (improvement of wettability, improved adhesion, biocompatibility) Improvement, etc.), cleaning and desmear treatment can be performed with high efficiency.
本発明の第 2の形態によれば、 前記格子定数 a力 S 3 . 8 0 A〜3 . 9 2 Aの範 囲にあるから、 本発明に係る P t * R h系金属は、 不純物の固溶が少なく、 好適 な加工性を有する電極材料となり、 この電極材料から所望の物性と形状を有する プラズマ生成用電極の放電表面提供することができる。 即ち、 前記格子定数が 3 . 8 O Aより小さくなると硬度が増加して加工が困難となる。 また、 前記格子定 数 aが 3 . 9 2 Aより大きくなると、 不純物が固溶し易くなり、 所望の特性をプ ラズマ生成用電極に付与することが困難となる。 本発明者等は、 鋭意研究の結果 、 前記電極材料として好適な格子定数を明らかにして、 前記格子定数の範囲を特 定するに到ったものである。  According to the second aspect of the present invention, since the lattice constant a force S3.80 A to 3.92 A is in the range, the Pt * Rh-based metal according to the present invention contains impurities. An electrode material having a small solid solution and suitable workability can be provided, and a discharge surface of a plasma generating electrode having desired physical properties and shape can be provided from this electrode material. That is, when the lattice constant is smaller than 3.8 O A, the hardness increases and machining becomes difficult. On the other hand, when the lattice constant a is larger than 3.92 A, impurities are easily dissolved, and it is difficult to impart desired characteristics to the plasma generating electrode. As a result of intensive studies, the present inventors have clarified a lattice constant suitable as the electrode material and have determined the range of the lattice constant.
本発明の第 3の形態によれば、 前記 P t - R h系金属の融点が 1 7 7 3 °C〜 1 9 6 6 °Cの範囲に設定されるから、 プラズマ生成時に前記放電表面が好適に軟化 され、 前記損耗材粒子の放出を抑制することができる。 損耗材粒子発生の要因の 1つとして、 前記放電表面における爆発現象 （火花損耗） があり、. 高融点金属材 料 （W、 M oなど） を電極材料として用いた場合、 高温においても所定以上の硬  According to the third aspect of the present invention, since the melting point of the Pt-Rh-based metal is set in a range of 1 77 3 ° C to 1 96 6 ° C, the discharge surface is formed during plasma generation. It is suitably softened and the release of the wear material particles can be suppressed. One of the causes of the generation of wear material particles is an explosion phenomenon (spark wear) on the discharge surface. When a high melting point metal material (W, Mo, etc.) is used as an electrode material, it is more than a specified value even at high temperatures. Hard
S 度が維持されるため火花損耗による損耗材粒子の放出され易いと考えられる。 本 発明に係る P t · R h系金属の場合、 優れた耐酸化性を有すると共に、 融点を好 適な範囲に設定することができ、 プラズマ生成時に前記放電表面が好適に軟化さ れ、 火花損耗による損耗材料粒子の放出を極めて微量に抑制することができる。 プラズマ生成用電極の少なくとも放電表面が P t一 R h合金から形成される場合 、 プラズマの用途や作動ガスの種類に応じて P tに対する R hの含有量を調整し 、 1 7 7 3 °C〜 1 9 6 6 °Cの範囲で電極材料の融点を好適な温度に設定すること ができる。 また、 他の卑金属 （N iなど） 、 好ましくは他の貴金属 （I rなど） を更に含有させることも可能であるが、 その場合においても 1 7 7 3 °C〜1 9 6 6 °Cの範囲に融点が設定されることにより、 火花損耗の発生を抑制することがで きる。 更に、 前記電極材料の機械的強度を考慮した場合、 前記融点が 1 7 7 3 °C 〜1 9 3 2 °Cの範囲に設定されることがより好ましく、 1 8 5 0 °C〜1 9 3 2 °C の範囲にある場合に最適となり得ることが実験から明らカにしている。 S Since the degree is maintained, it is considered that the wear material particles are easily released due to spark wear. In the case of the Pt · Rh-based metal according to the present invention, it has excellent oxidation resistance, the melting point can be set in a suitable range, the discharge surface is suitably softened during plasma generation, and a spark is generated. Release of wear material particles due to wear can be suppressed to a very small amount. If at least the discharge surface of the electrode for plasma generation is formed from a Pt-Rh alloy, adjust the Rh content relative to Pt according to the application of the plasma and the type of working gas, 1 7 7 3 ° C The melting point of the electrode material can be set to a suitable temperature within a range of ˜196 6 6 ° C. In addition, other base metals (such as Ni), preferably other noble metals (such as Ir) can be further added, but even in such a case, the temperature is from 1 77 3 ° C to 1 96 6 ° C. By setting the melting point in the range, the occurrence of spark wear can be suppressed. Furthermore, when the mechanical strength of the electrode material is taken into consideration, the melting point is more preferably set in a range of 1 77 3 ° C to 1 93 2 ° C, and 1 8500 ° C to 19 It is clear from experiments that it can be optimal when it is in the range of 3 ° C.
本発明の第 4の形態によれば、 前記 P t · R h系金属を形成する P t金属又は P t - R h合金が結晶子を形成し、 この結晶子の結晶構造が面心立方格子 （ F C C) 構造を有している。 一般的に、 面心立方格子の金属は加工し易く、 充填率が 高いため不純物の固溶が抑制される。 従って、 本発明に係る P t ' R h系金属を 前記電極材料に用いれば、 好適な電気的特性を有すると共に、 前記電極材料を所 定形状に容易に加工してプラズマ生成用電極を構成することができる。  According to the fourth aspect of the present invention, the Pt metal or Pt—Rh alloy forming the Pt · Rh-based metal forms a crystallite, and the crystal structure of the crystallite is a face-centered cubic lattice. (FCC) structure. In general, face-centered cubic lattice metals are easy to process and have a high filling rate, which suppresses solid solution of impurities. Therefore, if the Pt′Rh-based metal according to the present invention is used for the electrode material, it has suitable electrical characteristics, and the electrode material is easily processed into a predetermined shape to constitute a plasma generating electrode. be able to.
本発明の第 5の形態によれば、 前記 P t · R h系金属の結晶粒径が 0 . 5 μ m 〜 1 0 0 μ mの範囲にあるから、 前記電極材料に好適な耐スパッタ性が付与され 、 前記放電表面を均一に保持することができる。 結晶粒径が 1 0 0 μ mより大き , くなると耐スパッタ性が悪くなり、 プラズマの生成に好適な放電表面を保持でき なくなることが確かめられている。 結晶粒径が 0 . 5 μ mより小さな場合、 耐ス パッタ性は向上するが、 極めて微小な損耗粒子が多量に発生し易くなる傾向にあ つた。 従って、 前記結晶粒径が 0 . 5 μ II！〜 1 0 0 μ mの範囲に設定されること により、 本発明に係るプラズマ生成用電極を用いて均一で損耗粒子の少ないブラ ズマを生成することができる。  According to the fifth aspect of the present invention, since the crystal grain size of the Pt · Rh-based metal is in the range of 0.5 μm to 100 μm, the sputtering resistance suitable for the electrode material Is provided, and the discharge surface can be held uniformly. It has been confirmed that when the crystal grain size is larger than 100 μm, the sputtering resistance is deteriorated and a discharge surface suitable for plasma generation cannot be maintained. When the crystal grain size is smaller than 0.5 μm, the spatter resistance is improved, but a very large amount of wear particles tends to be generated easily. Therefore, the crystal grain size is 0.5 μ II! By setting the thickness within a range of ˜100 μm, it is possible to generate a uniform plasma with less wear particles using the plasma generating electrode according to the present invention.
本発明の第 6の形態によれば、 前記 P t . R h系金属の密度 pが 1 2 . 4 1 g ./'cm3〜21. 45 g, /cm3の範囲にあるから、 前記電極材料に含有される 不純物量を低減化できると共に、 電極形成時及び/又はプラズマ生成時における 放電表面のポーラス化を抑制することができる。 密度 pが 21. 45 g/'cm3 より大きくなると、 不純物の絶対量が増大すると共に不純物の混入を抑制するこ とが困難となり、 プラズマ生成用電極の電気的特性を所定値に設定することが困 難となる可能性があると共に、 損耗粒子と共にブラズマ中に前記不純物が混入す る惧れがあった。 また、 密度 pが 12. 41 g ' cm3より小さくなると、 電極 形成時及び/又はブラズマ生成時において、 放電表面がポーラス化する傾向が現 れ易くなり、 損耗粒子の発生を増大させる要因の 1つとなる惧れがあった。 従つ て、 前記 P t · R h系金属の密度 pを 12. 41 gZ'cm3〜21. 45 g / c m 3の範囲に設定することにより、 プラズマに不純物や損耗粒子が混入すること を低減化することができる。 According to the sixth aspect of the present invention, the density p of the P t .R h-based metal is 1 2.4 1 g. ./'cm 3 to 21.45 g, / cm 3 , so that the amount of impurities contained in the electrode material can be reduced and the discharge surface becomes porous during electrode formation and / or plasma generation. Can be suppressed. When the density p is greater than 21.45 g / 'cm 3 , the absolute amount of impurities increases and it becomes difficult to suppress the contamination of the impurities, and the electrical characteristics of the plasma generating electrode must be set to a predetermined value. There is a possibility that the impurities are mixed in the plasma together with the wear particles. Further, the density p is less than 12. 41 g 'cm 3, at the time of electrode formation during and / or Burazuma generation, tends to discharge surface is pore formation is easily present, factors that increase the generation of wear particles 1 There was a fear of becoming. Therefore, by setting the density p of the Pt · Rh-based metal in the range of 12.41 gZ'cm 3 to 21.45 g / cm 3 , impurities and wear particles can be mixed into the plasma. It can be reduced.
本発明の第 7の形態によれば、 前記 P t . R h系金属のビッカース硬度 H Vが 50Hv〜l 3 OH Vの範囲にあるから、 損耗粒子の発生を低減化できると共に 、 好適な硬度を前記放電表面に付与することができる。 前記ピツカ一ス硬度 HV が 130 H Vを越えると放電表面が脆くなり、 所定形状にプラズマ生成用電極を 加工することが困難となる。 また、 前記損耗粒子の発生が増大する傾向にあった 。 従って、 本発明に係る P t · Rh系金属は、 ビッカース硬度 HVが 5 OH v〜 1 3 OHvの範囲に設定されるから、 好適な耐久性を有すると共に、 損耗粒子の 発生量が少なく、 所望の形状を有するプラズマ生成用電極を提供することができ る。  According to the seventh aspect of the present invention, since the Vickers hardness HV of the Pt.Rh-based metal is in the range of 50 Hv to l 3 OH V, the generation of wear particles can be reduced and a suitable hardness can be achieved. It can be applied to the discharge surface. When the picker hardness HV exceeds 130 HV, the discharge surface becomes brittle and it becomes difficult to process the plasma generating electrode into a predetermined shape. In addition, the generation of the wear particles tends to increase. Therefore, the Pt · Rh metal according to the present invention has a Vickers hardness HV set in the range of 5 OH v to 13 OHv, so that it has a suitable durability and generates a small amount of wear particles. It is possible to provide a plasma generating electrode having the following shape.
本発明の第 8の形態によれば、 前記 P t ' Rh系金属の格子定数 a (A) と前 記 重量％の a— X関係式が +  According to the eighth embodiment of the present invention, the lattice constant a (A) of the P t 'Rh-based metal and the a-X relational expression of the weight% is +
a =- 0. 001 13 X+ 3. 908±0. 02  a =-0. 001 13 X + 3. 908 ± 0.02
で表されるから、 前記 Rhの重量比率を調整して所定の格子定数 aを有する電極 材料から前記放電表面を形成することができる。 本発明者等は、 プラズマ生成用 電極を用いたプラズマ処理の結果とその電極材料の X線回折 （XRD) 測定に基 づく分析から、 好適な電極材料の格子定数を明らかにし、 これらの実験結果から 前記 a— X関係式を導出している。 即ち、 Rhの重量比率を変化させ、 良好なプ ラズマ生成が可能な範囲において、 前記格子定数 aが前記 X重量％に対してどの ような依存性を持つかを導出したものである。 従って、 所望の格子定数を有する 電極材料を R hの含有量により選択し、 ブラズマ生成用電極を形成することがで きる。 R hの重量比率が 30重量％である場合、 前記格子定数 aを 3. 874士 0. 02 Aに設定することができる。 即ち、 3. 854A〜3. 894Aの範囲 内に格子定数 aを設定することができる。 Rhの重量比率が 40重量％である場 合は、 前記格子定数 aを 3. 863±0. 02A (3. 843 A〜 3. 883 A の範囲内） に設定することができる。 従って、 Rhの重量比率を調整して、 第 2 の形態に示した前述した格子定数の範囲 3. 80 A〜 3. 92 Aに前記格子定数 aを容易に設定することができる。 Therefore, the discharge surface can be formed from an electrode material having a predetermined lattice constant a by adjusting the weight ratio of Rh. The present inventors have clarified the lattice constant of a suitable electrode material from the results of plasma treatment using the electrode for plasma generation and the analysis based on the X-ray diffraction (XRD) measurement of the electrode material, and the results of these experiments. From the above, the a-X relational expression is derived. That is, by changing the weight ratio of Rh, It is derived what dependency the lattice constant a has on the X weight% in a range in which the generation of the laser is possible. Therefore, an electrode material having a desired lattice constant can be selected depending on the content of R h to form a plasma generating electrode. When the weight ratio of Rh is 30% by weight, the lattice constant a can be set to 3.874 people 0.02 A. That is, the lattice constant a can be set within the range of 3.854A to 3.894A. When the weight ratio of Rh is 40% by weight, the lattice constant a can be set to 3.863 ± 0.02A (within a range of 3.843 A to 3.883 A). Accordingly, by adjusting the weight ratio of Rh, the lattice constant a can be easily set to the above-described lattice constant range of 3.80 A to 3.92 A shown in the second embodiment.
本発明の第 9の形態によれば、 前記 P t ' Rh系金属の融点 T (°C) と前記 X 重量％の第 1の T一 X関係式が  According to the ninth aspect of the present invention, the first T-X relational expression of the melting point T (° C) of the P t 'Rh-based metal and the X weight% is
T =- 1. 4890 Χ+ 1836. 3±70  T =-1. 4890 Χ + 1836. 3 ± 70
で表されるから、 前記 Rhの重量比率を調整して前記融点 T (°C) を所定の温度 範囲に設定することができる。 前記 重量％が 30重量％である場合、 前記融点 T (。C) を 1881 ± 70。C (約 181 1 °C〜約 1951 °Cの範囲内） に設定す ることができ、 前記 X重量％が40重量％である場合、 前記融点 T (°C) を 18 96 ± 70。C (約 1826 °C〜約 1966 °Cの範囲内） に設定することができる 更に、 前記 X重量。 /0が 0≤X 30の範囲にあるとき第 2の T— X関係式は、 T = - 5. 255 Χ+ 1785. 3± 15 Therefore, the melting point T (° C.) can be set to a predetermined temperature range by adjusting the weight ratio of Rh. When the wt% is 30 wt%, the melting point T (.C) is 1881 ± 70. C (in the range of about 181 1 ° C to about 1951 ° C), and when the X wt% is 40 wt%, the melting point T (° C) is 18 96 ± 70. C (in the range of about 1826 ° C to about 1966 ° C) can be further set to the X weight. When / 0 is in the range 0≤X 30, the second T—X relation is T =-5. 255 Χ + 1785. 3 ± 15
で表すことができ、 誤差範囲が小さいから、 0≤Χ≤ 30の範囲において、 前記 Rhの重量比率を調整し、 前記融点 T (°C) をより確実に所定の温度範囲内に設 定することができる。 第 9の形態では、 近似的に線形の関数によつて前記融点 T (°C) の Rh含有量依存性を導出している。 後述するように、 Rh含有量依存性 が厳密には線形関数ではないため、 0≤ X≤ 30の範囲と 30く X≤ 100の範 囲では、 T一 X関係式の傾きが大きく変化する。 従って、 0≤X≤30の範囲の 測定データに基づき、 第 2の T— X関係式を導出し、 前記 重量％が 0重量％〜 30重量％の前記？ 1 · Rh系金属に適用することにより、 より高精度に前記融 Tを設定することができる。 第 2の Τ一 X関係式を適用すれば、 前記 重量％が 30重量0 /0である場合、 前記融点 T (°C) を 1890± 15。C (約 1875°C〜 約 1905°Cの範囲內） に設定することができる。 Since the error range is small, the weight ratio of Rh is adjusted in the range of 0≤Χ≤30, and the melting point T (° C) is more reliably set within the predetermined temperature range. be able to. In the ninth embodiment, the dependence of the melting point T (° C) on the Rh content is derived by an approximately linear function. As will be described later, since the Rh content dependency is not strictly a linear function, the slope of the T-X relation varies greatly between 0≤X≤30 and 30≤X≤100. Therefore, based on the measurement data in the range of 0≤X≤30, the second T—X relational expression is derived, and the weight% is 0 wt% to 30 wt%. 1 · By applying to Rh-based metals, T can be set. By applying the second Τ one X relationship, if the weight percent is 30 weight 0/0, the melting point T (° C) to 1890 ± 15. C (range from about 1875 ° C to about 1905 ° C).
前述のように、 前記融点 T (°C) を所定の温度範囲に設定することにより、 前 記電極材料の加工性等を向上させ、 ブラズマ生成時における前記損耗粒子の発生 量を抑制することができる。 従って、 前記 P t · Rh系金属の Rh含有量により 前記融点 T (°C) を簡易に設定できるから、 高性能のプラズマ生成用電極を低コ ストで製造することができる。  As described above, by setting the melting point T (° C.) within a predetermined temperature range, it is possible to improve the workability of the electrode material, and to suppress the generation amount of the wear particles at the time of plasma generation. it can. Therefore, since the melting point T (° C.) can be easily set depending on the Rh content of the Pt · Rh-based metal, a high-performance plasma generating electrode can be manufactured at a low cost.
本発明の第 10の形態によれば、 前記 P t · Rh系金属の密度/) (g.Zcm3 ) と前記 重量％の p— X関係式が According to a tenth aspect of the present invention, the density of the Pt · Rh-based metal /) (g.Zcm 3 ) and the weight percent p—X relational expression are
p =- 0. 08401 X+ 20. 87±0. 6  p =-0. 08401 X + 20. 87 ± 0.6
で表されるから、 前記 Rhの重量比率を調整して前記密度 pを所定の密度範囲内 に設定することができる。 前記 p— X関係式は、 プラズマ生成用電極を用いたプ ラズマ処理の結果と密度測定に基づき、 好適な電極材料の密度を明らかにして導 出されたものである。 前述のように、 前記密度 p (g cm3) に応じて不純物 の含有量等が変化し、 抵抗値など、 プラズマ生成用電極の電気的特性に影響を及 ぼす。 従って、 前記 p—X関係式を用いて、 前記 P t · Rh系金属の密度 pを容 易に制御できるから、 所望の電気的特性を有するプラズマ生成用電極を提供する ことができる。 前記 X重量。 /0が 30重量％である場合、 前記密度 pを 18. 26 ±0. 6 g.Zcm3 (約 17. 66 g c m3〜約 18. 86 gZcm3の範囲内 ) に設定することができ、 前記 X重量％が40重量％である場合、 前記融点 T ( °C) を 17. 51 ±0. 6 g/cm3 (約 16. 91 g, cm3〜18. 11約 g/cm3の範囲内） に設定することができる。 ， Therefore, the density p can be set within a predetermined density range by adjusting the weight ratio of Rh. The p—X relational expression is derived by clarifying the density of a suitable electrode material based on the plasma processing result using the plasma generating electrode and the density measurement. As described above, the impurity content and the like change according to the density p (g cm 3 ), which affects the electrical characteristics of the plasma generating electrode, such as the resistance value. Therefore, the density p of the P t · Rh-based metal can be easily controlled using the p-X relational expression, so that a plasma generating electrode having desired electrical characteristics can be provided. Said X weight. When / 0 is 30% by weight, the density p can be set to 18.26 ± 0.6 g.Zcm 3 (within a range of about 17.66 gcm 3 to about 18.86 gZcm 3 ), When the X wt% is 40 wt%, the melting point T (° C) is 17.51 ± 0.6 g / cm 3 (about 16.91 g, cm 3 to 18.11 about g / cm 3 (Within range). ,
本発明の第 1 1の形態によれば、 前記 P t · Rh系金属のピツカ一ス硬度 HV (Hv) と前記 重量％の HV— X関係式が  According to the first aspect of the present invention, the Pt · Rh-based metal pitch hardness HV (Hv) and the weight% HV-X relational expression are:
HV = - 2. 76 X+ 51. 85±15  HV =-2.76 X + 51. 85 ± 15
で表されるから、 前記 R hの重量比率を調整して前記ビッカース硬度 H Vを所定 範囲内に設定することができる。 前述のように、 前記ビッカース硬度 HVを所定 範囲内に設定することにより、 前記電極材料に好適な加工性が付与されると共に 、 プラズマ生成時における損耗粒子の発生を抑制することができる。 例えば、 前 記 X重量0 /0が 30重量0 /0である場合、 前記ビッカース硬度 HVを 135± 15H V (約 120 H V〜約 1 50 H Vの範囲内） に設定することができ、 前記 X重量 %が 20重量0 /0である場合、 前記ビッカース硬度 HV (Hv) を 107± 15Η V (約 92Η V〜約 1 22Η Vの範囲内） に設定することができる。 Therefore, the Vickers hardness HV can be set within a predetermined range by adjusting the weight ratio of Rh. As described above, by setting the Vickers hardness HV within a predetermined range, suitable workability is imparted to the electrode material. The generation of wear particles during plasma generation can be suppressed. For example, if the previous SL X weight 0/0 is 30 weight 0/0, it is possible to set the Vickers hardness HV to 135 ± 15H V (in the range of about 120 HV～ about 1 50 HV), wherein X wt% can be set in the case of 20 weight 0/0, the Vickers hardness HV of (Hv) 107 ± 15Η V (in the range of about 92Ita V to about 1 22Η V).
本発明の第 1 2の形態によれば、 前記 P t · Rh系金属に占める Rhの重量比 率が 0重量％〜40重量％の範囲に設定されるから、 前記電極材料が好適な機械 的強度を有し、 プラズマ生成用電極の長寿命化が図れると共に、 容易に所望の形 状に加工することができる。 従って、 ペンジェット用やグラインデイングアーク 用など、 用途に応じて種々の形状のプラズマ生成用電極を提供することができる 。 本発明者等は、 前記 P t · Rh系金属の Rh含有量が増大するとアーク放電に おける電極の損耗量が減少するが、 Rhの重量比率が 40重量％より大きくなる とブラズマ生成用電極の機械的強度が顕著に低下することが実験から確かめられ ている。 即ち、 前記 P t · Rh系金属に含有される Rhの重量比率が 0〜40重 量％の範囲に設定されることにより、 本発明に係るプラズマ生成用電極に好適な 硬度、 引張り強度ゃ靱性などが付 される。 更に、 上記の実験結果では、 Rhの 重量比率が 10〜 30重量％に設定される場合に、 より好適な機械的強度を得る ことができる。  According to the first and second aspects of the present invention, since the weight ratio of Rh to the Pt · Rh-based metal is set in the range of 0 wt% to 40 wt%, the electrode material is a suitable mechanical material. It has strength and can extend the life of the plasma generation electrode and can be easily processed into a desired shape. Therefore, it is possible to provide plasma generation electrodes having various shapes depending on the application, such as for pen jets and grinding arcs. When the Rh content of the Pt · Rh-based metal increases, the amount of wear of the electrode in the arc discharge decreases. However, when the Rh weight ratio exceeds 40% by weight, the present inventors Experiments have confirmed that the mechanical strength is significantly reduced. That is, by setting the weight ratio of Rh contained in the Pt · Rh-based metal in the range of 0 to 40% by weight, the hardness and tensile strength suitable for the plasma generating electrode according to the present invention are tough. Etc. are attached. Furthermore, in the above experimental results, more suitable mechanical strength can be obtained when the weight ratio of Rh is set to 10 to 30% by weight.
更に、 第 8〜第 1 1の形態で用いられる各関係式を用いれば、 Rhの重量比率 が 0〜 40重量0 /0の範囲にある場合、 前記格子定数 aは 3. 863±0. 02A 〜3. 908±0. 02 Aの範囲に設定することができる。 更に、 前記融点 Tは 、 1836±70°C〜1896±70°Cの範囲に設定することができ、 前記密度 /)を 1 7. 51 ±0. 6 §ノ 1113〜20. 87±0. 6 g/ cm3の範囲に設 定することができる。 Furthermore, the use of the equation used in the eighth to 1 1 embodiment, if the weight ratio of Rh is in the range of 0 to 40 wt 0/0, the lattice constant a 3. 863 ± 0. 02A Can be set in the range of ~ 3.908 ± 0.02 A. Further, the melting point T can be set in a range of 1836 ± 70 ° C. to 1896 ± 70 ° C., and the density /) is 17.51 ± 0.6 §no 111 3 to 20.87 ± 0. Can be set in the range of 6 g / cm 3 .
本発明の第 1 3の形態によれば、 高電界電極と低電界電極を対向させて構成さ れる電極に放電が生起される場合に、 前記高電界電極の前記対向面側にある放電 表面が前記電極材料から形成される力 ら、 高電界による損耗材料粒子の放出を抑 制することができる。 ここで、 前記高電界電極は、 絶対 のより大きな電圧が印 加され、 電子を放出する高電圧電極 （陰極） に相当し、 前記低電界電極は、 例え ば接地電極のように、 絶対値のより小さな電圧が印加される低電圧電極 （陽極） に対応している。 ただし、 電圧の印加方法によっては、 高電界電極が陽極、 低電 界電極が陰極の場合のように逆の場合もありうる。 放電を生起させる電極に電界 を集中させる放電表面の構造、 例えば電極面に設けられた突起先端や針状電極の 先端などが形成される場合、 このような構造を有する電極は対向する電極に比べ 、 電界が集中して高電界電極を構成する。 ここで、 前記対向する電極は、 高電界 電極に比べて電界または印加電圧が低く、 低電界電極を構成する。 従って、 少な くとも高電界電極の放電表面を前記 P t · R h系金属の電極材料から形成すれば 、 損耗材料粒子の発生が抑制され、 高純度のプラズマを生成することができる。 本発明の第 1 4の形態によれば、 前記高電界電極が棒状電極であり、 前記低電 界電極が前記ノズル状電極であり、 前記電極がペンジエツト型電極を構成するか ら、 本発明に係るプラズマ生成用電極を用いて、 前記損耗材料粒子の含有量が極 めて少なく、 高純度のジェット状プラズマ流を生成することができる。 ペンジェ ット型電極は、 前記棒状電極の先端側にプラズマ射出口を有するノズル状電極か ら構成され、 前記棒状電極とノズル状電極に電圧が印加して、 前記棒状電極の先 端面及び先端面近傍の放電表面に電界を集中させる。 従って、 前記棒状電極の少 なくとも先端面及び先端面近傍の放電表面を P t · R h系金属から形成されるこ とにより； 電界を集中する先端面及び先端面近傍から前記損耗材料粒子が放出さ れることを抑制することができる。 According to the thirteenth aspect of the present invention, when a discharge is generated in an electrode configured by opposing a high field electrode and a low field electrode, the discharge surface on the facing surface side of the high field electrode is Due to the force formed from the electrode material, it is possible to suppress the release of wear material particles due to a high electric field. Here, the high electric field electrode is applied with an absolute larger voltage and corresponds to a high voltage electrode (cathode) that emits electrons, and the low electric field electrode is, for example, For example, it corresponds to a low voltage electrode (anode) to which a voltage having a smaller absolute value is applied, such as a ground electrode. However, depending on the voltage application method, the reverse may be the case, such as when the high field electrode is the anode and the low field electrode is the cathode. When a discharge surface structure that concentrates the electric field on the electrode that causes discharge, such as the tip of a protrusion provided on the electrode surface or the tip of a needle electrode, is formed, the electrode having such a structure is compared to the opposite electrode. The electric field concentrates to form a high electric field electrode. Here, the opposing electrode has a lower electric field or applied voltage than the high electric field electrode, and constitutes a low electric field electrode. Therefore, if at least the discharge surface of the high electric field electrode is formed from the electrode material of the Pt · Rh-based metal, generation of wear material particles can be suppressed and high-purity plasma can be generated. According to the fourteenth aspect of the present invention, the high electric field electrode is a rod-shaped electrode, the low electric field electrode is the nozzle-shaped electrode, and the electrode constitutes a pendant electrode. Using the plasma generating electrode, it is possible to generate a high-purity jet plasma flow with an extremely low content of the wear material particles. The pen-type electrode is composed of a nozzle-like electrode having a plasma injection port on the tip side of the rod-like electrode, and a voltage is applied to the rod-like electrode and the nozzle-like electrode. Concentrate the electric field on the nearby discharge surface. Therefore, by forming at least the tip surface of the rod-shaped electrode and the discharge surface near the tip surface from a Pt · Rh-based metal; the wear material particles are generated from the tip surface and the tip surface vicinity where the electric field is concentrated. It can be suppressed from being released.
更に、 ペンジェット型電極では、 プラズマ発生部の外周に水冷部を設ける又は 気流を流入させることによりプラズマ流を冷却して、 その流束の大きさを容易に 制御すると共に安定化を図ることができる。 従って、 前記放電表面を P t - R h 系金属から形成して高純度のジヱット状プラズマ流を生成するこ.とにより、 ブラ ズマを被処理物表面の所定領域に照射して、 不純物を堆積 ·混入させることなく 、 均一な表面加工や表面改質等を行うことができる。 また、 前記棒状電極として 管状の電極を用いることができ、 管内に作動ガスを供給し、 管状電極先端とノズ ル'状電極內面に電圧を印加することにより、 作動ガスのアークプラズマを生成す ることができる。 .  Further, in the pen jet type electrode, it is possible to cool the plasma flow by providing a water cooling part on the outer periphery of the plasma generating part or by introducing an air flow, to easily control the size of the flux and to stabilize it. it can. Therefore, by forming the discharge surface from a Pt-Rh-based metal and generating a high purity jet plasma flow, the plasma is irradiated to a predetermined region on the surface of the object to be processed, thereby depositing impurities. · Uniform surface processing and surface modification can be performed without mixing. In addition, a tubular electrode can be used as the rod-shaped electrode, and a working gas is supplied into the tube, and a voltage is applied to the tip of the tubular electrode and the nozzle surface of the nozzle electrode to generate arc plasma of the working gas. Can. .
本発明の第 1 5の形態によれば、 前記棒状電極の少なくとも先端部が P t · R h系金属により一体形成されるから、 電極損耗が極めて少なく長寿命のプラズマ 生成用電極を簡易に製造することができる。 即ち、 前記棒状電極の少なくとも先 端部全体が前記電極材料から形成されるから、 前記 P t · R h系金属の棒状電極 へのコーティング等の特殊な加工が必要とされず、 前記放電表面が P t · R h系 金属からなる前記棒状電極を製造することができる。 更に、 前記棒状電極の少な くとも先端部全体が前記 P t · R h系金属から形成されるから、 微量な電極損耗 の蓄積により前記 P t · R h系金属の放電表面が失われる とが無く、 プラズマ 生成用電極の長寿命化を図ることができる。 また、 前記 P t ' R h系金属から形 成される先端部のみを交換することにより、 プラズマ生成用電極として使用する ことができ、 棒状電極全体を高価な P t · R h系金属から形成する場合に比べて 、 プラズマ生成用電極の製造コストを低減化することができる。 According to the fifteenth aspect of the present invention, at least the tip of the rod-shaped electrode is P t · R Since it is integrally formed of an h-based metal, it is possible to easily manufacture a long-life plasma generating electrode with very little electrode wear. That is, since at least the entire tip of the rod-shaped electrode is formed from the electrode material, no special processing such as coating of the Pt · Rh-based metal rod-shaped electrode is required, and the discharge surface is The rod-shaped electrode made of Pt · Rh-based metal can be manufactured. Furthermore, since at least the entire tip of the rod-shaped electrode is formed from the Pt · Rh-based metal, the discharge surface of the Pt · Rh-based metal may be lost due to the accumulation of a small amount of electrode wear. In addition, the life of the plasma generating electrode can be extended. In addition, by exchanging only the tip formed from the Pt'Rh metal, it can be used as an electrode for plasma generation, and the entire rod-shaped electrode is formed from an expensive PtRh metal. Compared with the case, the manufacturing cost of the plasma generating electrode can be reduced.
本発明の第 1 6の形態によれば、 前記高電界電極が放電表面側に 1つ以上の突 起を有する突起型電極であるから、 前記放電表面に形成された 1つ以上の突起に 電界を集中させ、 高効率にプラズマを生成することができる。 更に、 上述のよう に、 電界を集中する前記突起型電極の放電表面が前記 P t · R h系金属から形成 される力 ら、 電極損耗が抑制され、 損耗材料粒子の混入が極めて少ない高純度の プラズマを高効率に生成することができる。  According to the sixteenth aspect of the present invention, since the high electric field electrode is a protruding electrode having one or more protrusions on the discharge surface side, an electric field is applied to the one or more protrusions formed on the discharge surface. And can generate plasma with high efficiency. Further, as described above, the force that the discharge surface of the protruding electrode that concentrates the electric field is formed from the Pt · Rh-based metal suppresses electrode wear and has high purity with very little contamination of wear material particles. The plasma can be generated with high efficiency.
本発明の第 1 Ίの形態によれば、 第 1〜 7のいずれかの形態のブラズマ生成用 電極を用いてブラズマを生成するから、 長時間安定して高純度のブラズマを射出 するプラズマ生成装置を提供することができる。 本発明に係るプラズマ生成装置 の供給される作動ガスは、 気体 ·蒸気状であればなんでもよく、 例えば、 室内空 気、 乾燥空気、 加湿空気、 ヘリウム、 アルゴン、 酸素、 窒素、 水素、 硫化水素、 炭化水素ガス及びこれらの混合気体から目的に応じて適宜選択して、 前記損耗材 料粒子の混入が極めて少ない高純度のプラズマを生成することができる。 また、 それらの作動ガスに粉体を混合させることもできる。 前記作動ガスの圧力範囲は 、 以下の範囲に特定されるものではないが、 圧力の下限が電極の蒸発の少ない圧 力条件として大気圧の 1 ,ノ1 0程度 （0 . l a t m程度） であり、 圧力の上限は 、 作動ガスを安全に利用できる値として 1 0 a t m程度までが好ましい。 更に、 前記作動ガスの圧力は、 0 . 5〜5 a t mの範囲に設定されることがより好まし 52803 According to the first aspect of the present invention, since the plasma is generated using the plasma generating electrode according to any one of the first to seventh aspects, the plasma generating apparatus that stably injects high-purity plasma for a long time. Can be provided. The working gas supplied to the plasma generating apparatus according to the present invention may be anything in the form of gas or vapor. For example, indoor air, dry air, humidified air, helium, argon, oxygen, nitrogen, hydrogen, hydrogen sulfide, A high-purity plasma in which the wear material particles are very little mixed can be generated by appropriately selecting from hydrocarbon gas and mixed gas thereof according to the purpose. It is also possible to mix powder with these working gases. The pressure range of the working gas is not limited to the following range, but the lower limit of the pressure is about 1 to 10 (about 0.3 latm) of atmospheric pressure as a pressure condition with less evaporation of the electrode. The upper limit of the pressure is preferably up to about 10 atm as a value for safely using the working gas. Further, it is more preferable that the pressure of the working gas is set in a range of 0.5 to 5 atm. 52803
く、 ペンジ-ット型電極ゃグラインディングアーク型電極を具備するプラズマ生 成装置により、 所望のプラズマを安定に発生させることができる。 In addition, a desired plasma can be stably generated by a plasma generating apparatus provided with a pendant type electrode and a grinding arc type electrode.
本発明の第 1 8の形態によれば、 第 8の形態のブラズマ生成装置により被処理 物表面をブラズマ処理するから、 前記被処理物表面へ損耗材料粒子が不純物とし て付着 ·堆積 ·混入することを防止することができる。 更に、 電極損耗が抑制さ れることにより、 被処理物表面の表面処理を連続的に長時間実施することができ る。 本発明に係るプラズマ処理装置によれば、 前述したプラズマ溶射、 熱プラズ マ C V D法、 薄膜加工、 金属の溶解精鍊ゃ熱分解、 金属酸化物の還元、 表面改質 、 洗浄及びデスミア処理、 粉体合成 ·処理、 薄膜形成等のプラズマ処理を前記損 耗材料粒子の混入 ·堆積を極めて低減化して行うことができる。  According to the eighteenth aspect of the present invention, the surface of the object to be processed is subjected to the plasma treatment by the plasma generating apparatus according to the eighth aspect, so that the wear material particles adhere, deposit, and mix as impurities on the surface of the object to be processed This can be prevented. Furthermore, since electrode wear is suppressed, surface treatment of the surface of the workpiece can be continuously performed for a long time. According to the plasma processing apparatus of the present invention, the above-described plasma spraying, thermal plasma CVD method, thin film processing, metal dissolution and thermal decomposition, metal oxide reduction, surface modification, cleaning and desmear treatment, powder Plasma treatments such as synthesis / treatment and thin film formation can be performed with extremely reduced contamination / deposition of the wear material particles.
(図面の簡単な説明） ' (Brief description of drawings) '
図 1は、 本発明に係るペンジェット型電極を有するプラズマ処理装置の構成概 略図である。  FIG. 1 is a schematic configuration diagram of a plasma processing apparatus having a pen jet electrode according to the present invention.
図 2は、 本発明に係るペンジェット型プラズマ処理装置の射出口から射出され るブラズマを撮像した写真図である  FIG. 2 is a photograph showing an image of a plasma emitted from an injection port of a pen jet type plasma processing apparatus according to the present invention.
図 3は、 本発明に係る両電極水冷ペンジェット型電極を有するプラズマ生成装 置の断面概略図である。  FIG. 3 is a schematic cross-sectional view of a plasma generating apparatus having a double-electrode water-cooled pen jet electrode according to the present invention.
図 4は、 本発明に係る電極先端部の断面概略図である。  FIG. 4 is a schematic cross-sectional view of the electrode tip according to the present invention.
図 5は、 本発明に係る P t · R h系金属製電極先端部と比較例の P t— I r合 金製の各電極先端部をアーク放電後に撮像した電極先端部の拡大写真図である。 図 6は、 本発明に係る P t金属製電極先端部をプラズマ生成後に撮像した拡大 写真図である。  FIG. 5 is an enlarged photograph of the tip of the Pt · Rh-based metal electrode according to the present invention and the tip of each electrode made of Pt—Ir alloy in the comparative example, taken after arc discharge. is there. FIG. 6 is an enlarged photograph showing the Pt metal electrode tip according to the present invention imaged after plasma generation.
図 7は、 比較例である P t— I r合金 （ 7 A) 及び P t一 W合金 （ 7 B ) から なる各電極先端部の放電後の拡大写真図である。  FIG. 7 is an enlarged photograph after discharge of each electrode tip portion made of the Pt—Ir alloy (7A) and the Pt—W alloy (7B) as comparative examples.
図 8は、 本発明に係る P t金属及び P t— R h合金の電極先端部と比較例の P t一 I r合金電極先端部を用いた電極損耗量の電力依存性を示すグラフ図である 図 9は、 本発明に係るプラズマ処理装置によりプラズマ処理された被処理物表 面の光学顕微鏡写真図である。 FIG. 8 is a graph showing the power dependence of the electrode wear amount using the electrode tip of the Pt metal and Pt—Rh alloy according to the present invention and the Pt-Ir alloy electrode tip of the comparative example. FIG. 9 is a table of workpieces that have been plasma processed by the plasma processing apparatus according to the present invention. It is an optical microscope photograph figure of a surface.
図 10は、 本発明に係る P.t · Rh系金属製と比較例である各種金属からなる 電極先端部の積算放電時間 （m i n) に対する積算損耗量 （mg) を示すグラフ 図である。  FIG. 10 is a graph showing the cumulative amount of wear (mg) with respect to the cumulative discharge time (m i n) of the electrode tip made of Pt · Rh metal according to the present invention and various comparative metals.
図 1 1は、 本発明に係る P t一 R h合金を電極材料として用いたプラズマ生成 用電極における損耗量の放電時間依存性を示すグラフ図である。  FIG. 11 is a graph showing the discharge time dependence of the amount of wear in a plasma generating electrode using a Pt—Rh alloy according to the present invention as an electrode material.
図 12は、 本発明に係る P t · Ph系金属の XRD分析 結果を示すグラフ図 である。  FIG. 12 is a graph showing the XRD analysis results of the Pt · Ph metal according to the present invention.
図 13は、 図 12の破線内を拡大したグラフ図である。  FIG. 13 is an enlarged graph of the inside of the broken line in FIG.
図 14は、 本発明に係る P t · Rh系金属の Rh含有量 （重量％) に対する格 子定数を示すグラフ図である。  FIG. 14 is a graph showing the lattice constant with respect to the Rh content (% by weight) of the Pt · Rh metal according to the present invention.
図 15は、 本発明に係る電極材料である P t—Rh合金の状態図である。 図 16は、 本発明に係る P t · Rh系金属と他の金属及び合金の融点を記載し た表図である。  FIG. 15 is a phase diagram of a Pt—Rh alloy which is an electrode material according to the present invention. FIG. 16 is a table showing the melting points of the Pt · Rh metal and other metals and alloys according to the present invention.
図 1 7は、 本発明に係る P t · Rh系金属の融点を Rhの重量比率 （X重量％ ) に対してプロットしたグラフ図である。  FIG. 17 is a graph plotting the melting point of the Pt · Rh metal according to the present invention against the weight ratio of Rh (X wt%).
図 18は、 本発明に係る P t · Rh系金属の融点を Rhの重量比率 （ 重量％ ) に対してプロットしたグラフ図である。 （0重量％〜30重量％)  FIG. 18 is a graph in which the melting point of the Pt · Rh metal according to the present invention is plotted against the weight ratio (% by weight) of Rh. (0% to 30% by weight)
図 19は、'本発明に係る P t · Rh系金属の密度 pを Rhの重量比率 （X重量 %) に対してプロットしたグラフ図である。  FIG. 19 is a graph in which the density p of the Pt · Rh metal according to the present invention is plotted against the weight ratio of Rh (X wt%).
図 20は、 本発明に係る P t · Rh系金属のビッカース硬度 HVを Rhの重量 比率 （ 重量％) に対してプロットしたグラフ図である。  FIG. 20 is a graph plotting the Vickers hardness HV of the Pt · Rh-based metal according to the present invention against the weight ratio (% by weight) of Rh.
図 21は、 本発明に係る管状の棒状電極を有するペンジエツト型プラズマ処理 装置の構成概略図である。  FIG. 21 is a schematic configuration diagram of a pendant plasma processing apparatus having a tubular rod electrode according to the present invention.
図 22は、 本発明に係るプラズマ生成用電極がグラインディングアーク型電極 であるブラズマ発生部の構成概略図である。  FIG. 22 is a schematic configuration diagram of a plasma generating portion in which the plasma generating electrode according to the present invention is a grinding arc type electrode.
図 23は、 本発明に係るプラズマ発生用電極が鋸刃状電極を具備する場合の概 略構成図である。  FIG. 23 is a schematic configuration diagram in the case where the plasma generating electrode according to the present invention includes a sawtooth electrode.
図 24は、 従来のプラズマ生成用電極におけるプラズマ生成の模式図である。 図 2 5は、 従来の W又は C uからなる棒状電極を用いてアークプラズマを発生 させた場合の電極先端の拡大写真図である。 FIG. 24 is a schematic diagram of plasma generation in a conventional plasma generation electrode. Fig. 25 is an enlarged photograph of the electrode tip when arc plasma is generated using a conventional rod-shaped electrode made of W or Cu.
(発明を実施するための最良の形態） (Best Mode for Carrying Out the Invention)
以下に、 本発明の実施形態を添付する図面に従って詳細に説明する。  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
図 1は、 本発明に係るペンジェット型電極を有するプラズマ処理装置 2 (以下' 「ペンジェット型プラズマ処理装置」 とも呼ぶ） の構成概略図である。 プラズマ 処理装置 2は、 ブラズマ生成器 4及び電源部 6からなるブラズマ生成装置 7と被 処理物 2 2が載置される処理部 （図示せず） 力 ら構成される。 前記プラズマ生成 器 4には、 棒状電極 8とノズル状電極 1 6からなるペンジェット型電極が配設さ れている。 前記プラズマ生成器 4を構成するガイド本体 2 4には、 前記棒状電極 8が内装され、 ガイ ド本体 2 4の射出口 1 6 b側に前記ノズル状電極 1 6が配設 されている。  FIG. 1 is a schematic configuration diagram of a plasma processing apparatus 2 having a penjet electrode according to the present invention (hereinafter also referred to as “penjet plasma processing apparatus”). The plasma processing apparatus 2 includes a plasma generating apparatus 7 including a plasma generator 4 and a power supply unit 6, and a processing unit (not shown) force on which the workpiece 22 is placed. The plasma generator 4 is provided with a pen jet electrode composed of a rod-shaped electrode 8 and a nozzle-shaped electrode 16. The guide body 24 constituting the plasma generator 4 is provided with the rod-shaped electrode 8, and the nozzle-shaped electrode 16 is disposed on the side of the injection port 16b of the guide body 24.
ガス導入口 3 0から供給される作動ガス 2 8は、 前記ガイド本体 2 4内を流通 し、 プラズマ発生部 4 aに供給されてプラズマ化され、 前記作動ガス 2 8のガス 供給圧により、 前記ノズル状電極 1 6の射出口 1 6 bからブラズマ Pが流束とし て射出される。 図 2には、 本発明に係るペンジェット型プラズマ処理装置 2の射 出口 1 6 bから射出されるプラズマ Pを撮像した写真図を示している。 後述する 試験では、 乾燥空気が作動ガス 2 8として用いられ、 ガス供給圧が 0 . 2 M P a 、 ガス流量が 2 0 L ,/ m i nに設定されている。 乾燥空気が作動ガス 2 8として 用いられ場合、 N 2+や 0 2+等からなるプラズマ流が被処理物 2 2に照射される 本発明に係るペンジェット型プラズマ処理装置によれば、 前記作動ガス 2 8と して、 乾燥空気、 加湿空気、 ヘリウム、 アルゴン、 酸素、 窒素、 水素、 硫化水素 、 炭化水素ガス及びこれらの混合気体から目的に応じて適宜選択し、 所望のブラ ズマ Pを生成することができる。 図示していないが、 前記ガス導入口 3 0への作 動ガスの供給は、 市販のガスボンベ、 コンプレッサ、 ブロア、 窒素ガス供給装置 などを利用できる。 また、 作動ガスの流量制御には、 市販のバルブ、 マスフロー コントローラやロタメーターなどを利用することができ、 流量計測器を加えても 良く、 ガス供給圧を制御するレギユレータ （図示せず） が配置される。 The working gas 28 supplied from the gas inlet 30 circulates in the guide main body 24, is supplied to the plasma generation unit 4a and is converted into plasma, and the gas supply pressure of the working gas 28 is used to The plasma P is ejected as a flux from the injection port 16 b of the nozzle electrode 16. FIG. 2 shows a photograph of the plasma P emitted from the outlet 16 b of the pen jet type plasma processing apparatus 2 according to the present invention. In the test to be described later, dry air is used as the working gas 28, the gas supply pressure is set to 0.2 MPa, and the gas flow rate is set to 20 L, / min. If dry air is used as working gas 2 8, according to the pen-jet plasma processing apparatus according to the present invention the plasma stream comprising N 2 + and 0 2 + and the like are delivered to the object 2 2, the actuating As gas 28, select from dry air, humidified air, helium, argon, oxygen, nitrogen, hydrogen, hydrogen sulfide, hydrocarbon gas and mixed gas according to the purpose to produce the desired plasma P can do. Although not shown, the working gas can be supplied to the gas inlet 30 using a commercially available gas cylinder, compressor, blower, nitrogen gas supply device, or the like. In addition, commercially available valves, mass flow controllers, and rotameters can be used to control the flow rate of working gas. A regulator (not shown) for controlling the gas supply pressure is arranged.
図 1に示すように、 ガイド本体 2 4の外周には、 水冷電極キヤップ 1 8が設け られ、 前記ノズル状電極 1 6は水冷電極キヤップ 1 8を介してアース 2 0に接続 されている。 冷却水 1 8 aを循環させることにより、 前記ノズノレ状電極 1 6及び プラズマ発生部 4 aが冷却され、 ノズ 状電極 1 6の損傷とプラズマの拡散が防 止される。 また、 プラズマ発生部 4 a周辺には絶縁部 2 6が形成され、 アース 2 ' 0に接続される水冷電極キヤップ 1 8と棒状電極 8の間に電界が形成されること を防止している。  As shown in FIG. 1, a water-cooled electrode cap 18 is provided on the outer periphery of the guide body 24, and the nozzle electrode 16 is connected to the ground 20 through the water-cooled electrode cap 18. By circulating the cooling water 18 a, the nodular electrode 16 and the plasma generating part 4 a are cooled, and damage to the nodular electrode 16 and plasma diffusion are prevented. Further, an insulating portion 26 is formed around the plasma generating portion 4 a to prevent an electric field from being formed between the water-cooled electrode cap 18 connected to the ground 2 ′ 0 and the rod-shaped electrode 8.
更に、 前記棒状電極 8は、 P t · R h系金属からなる電極先端部 1 0と、 タン ダステンやステンレスなど高融点の卑金属から形成される電極基端部 1 2から構 成され、 前記電極先端部 1 0と前記電極基端部 1 2とは、 電気伝導性の良い C u 又は N iなどから形成されるスリーブ 1 4により電気的に導通状態で接続される 。 従って、 長期間の使用により電極先端部 1 0の損耗が増大した場合、 P t ' R h系金属からなる電極先端部 1 0のみを交換することができる。 この実施例にお いて、 前記電極先端部 1 0は、 直径 1 . 6 mm、 長さ 9〜： 1 O mmの電極材料を 用いている。 この電極先端部 1 0の長さ及び直径は適宜に変更可能であるが、 図 1のペンジェット型電極の場合、 前記電極先端部 1 0の直径は、 電界を電極先端 面 1 0 aに集中させるために 0 . 5 mm〜 3 mm程度に設定されることが好まし い  Further, the rod-shaped electrode 8 is composed of an electrode tip portion 10 made of a Pt · Rh-based metal and an electrode base end portion 12 made of a base metal having a high melting point such as tandastene or stainless steel. The distal end portion 10 and the electrode base end portion 12 are electrically connected by a sleeve 14 formed of Cu or Ni having good electrical conductivity. Therefore, when the wear of the electrode tip portion 10 increases due to long-term use, only the electrode tip portion 10 made of Pt′Rh-based metal can be replaced. In this embodiment, the electrode tip 10 is made of an electrode material having a diameter of 1.6 mm and a length of 9 to 1 O mm. The length and diameter of the electrode tip 10 can be appropriately changed. In the case of the pen jet type electrode of FIG. 1, the diameter of the electrode tip 10 is such that the electric field is concentrated on the electrode tip surface 10a. It is preferable to set to about 0.5 mm to 3 mm
前述のように、 前記作動ガス 1 8は、 前記プラズマ生成器 4のガス導入口 3 0 から前記棒状電極 8の側面とガイ ド本体 2 4の間を流通して作動ガス 1 8がブラ ズマ発生部 4 aに供給される。 電極先端面 1 0 a又はこの電極先端面 1 0 aとそ の近傍が放電表面となり、 前記プラズマ発生部 4 aに供給された作動ガス 2 8は 、 前記電極先端面 1 0 aとノズル状電極内面 1 6 aの間のアーク放電によりブラ ズマ化され、 射出口 1 6 bからプラズマ Pが被処理物 2 2の表面に照射される。 後述の試験では、 棒状電極 8の電極先端面 1 0 aからノズル'状電極の最近接位置 までの電極間ギャップは、 約 2 mmに設定され、 前記射出口 1 6 aと被処理物 2 2間の照射距離 dは、 1 0 mmに設定されている。  As described above, the working gas 18 flows from the gas inlet 30 of the plasma generator 4 between the side surface of the rod-shaped electrode 8 and the guide body 24, and the working gas 18 is generated as a plasma. Supplied to part 4a. The electrode front end surface 10a or the electrode front end surface 10a and the vicinity thereof become a discharge surface, and the working gas 28 supplied to the plasma generating unit 4a is composed of the electrode front end surface 10a and the nozzle-like electrode. Plasma is generated by arc discharge between the inner surface 16 a and the surface of the workpiece 22 is irradiated with plasma P from the injection port 16 b. In the test described later, the interelectrode gap from the electrode tip surface 10 a of the rod-shaped electrode 8 to the closest position of the nozzle-shaped electrode is set to about 2 mm, and the injection port 16 a and the workpiece 2 2 The irradiation distance d between them is set to 10 mm.
前記棒状電極 8に印加される電位は、 前記電源部 6から供給されるパルス電流 によって付与される。 この実施例において、 前記電源部 6は、 三相交流電源 3 1 に接続されたパルスモジュレ タ 3 2と、 コイル · 4 0とコンデンサ 4 2からなる L C直列回路及ぴアース 4 1に接続された高電圧トランス 3 8から構成される。 パルスモジュレータ 3 2により、 パルス周波数及びパルス幅を自在に調整するこ とができる。 更に、 高電圧トランス 3 8により昇圧され、 高電圧パルスが棒状電 極 8と接地されたノズル状電極 1 6の間に印加される。 また、 上記 L C直列回路 では、 コンデンサ 4 2における充電電圧の低下がコイル 4 Qによって抑制され、 コンデンサ 4 2からの放電によって電極先端面 1 0 aに付与される電位が放電可 能電位に保持される。 後述する各種の電極先端部 1 0を用いた電極損耗の試験で は、 印加される高電圧パルスのパルス幅が約 2 H s、 パルス周波数が約 2 0 k H zに設定されている。 The potential applied to the rod-shaped electrode 8 is a pulse current supplied from the power supply unit 6. Is granted by. In this embodiment, the power supply unit 6 is connected to a pulse modulator 3 2 connected to a three-phase AC power supply 3 1, an LC series circuit comprising a coil 40 and a capacitor 4 2, and an earth 4 1. Consists of high voltage transformers 3-8. With the pulse modulator 3 2, the pulse frequency and pulse width can be adjusted freely. Further, the voltage is boosted by the high voltage transformer 38 and a high voltage pulse is applied between the rod electrode 8 and the grounded nozzle electrode 16. Further, in the above LC series circuit, the decrease in the charging voltage in the capacitor 42 is suppressed by the coil 4 Q, and the potential applied to the electrode tip surface 10 a by the discharge from the capacitor 42 is held at the dischargeable potential. The In the electrode wear test using various electrode tips 10 described later, the pulse width of the applied high voltage pulse is set to about 2 H s and the pulse frequency is set to about 20 kHz.
図 1の実施例では、 '水冷電極キヤップ 1 8 aを介してアース 2 0に接続される 前記ノズル状電極 1 6と電極先端面 1 0 aの間に高電圧パルスによってアーク放 電が生起され、 熱電子放出， 電界放出， またはショットキー放出された電子によ りプラズマ Pが生成される。 このとき、 前記電極間ギャップには、 前記高電圧パ ノレスにより 1 0〜1 5 k Vの電圧が印加され、 アーク放電により前記電極間ギヤ ップの電圧はおよそ 5 k V程度に低下する。 更に、 前記パルスモジユレータ 3 2 には、 電力調整器 3 4及び電力計 3 6が付設されており、 供給電力を自在に調整 することができ、 上記アーク放電電位を保持するため、 後述の試験においては 1 0 0 W〜5 0 0 Wの範囲に設定されている。  In the embodiment of FIG. 1, arc discharge is caused by a high voltage pulse between the nozzle-like electrode 16 connected to the ground 20 through the water-cooled electrode cap 18 a and the electrode tip surface 10 a. Plasma P is generated by thermionic emission, field emission, or Schottky emitted electrons. At this time, a voltage of 10 to 15 kV is applied to the gap between the electrodes by the high voltage panel, and the voltage of the gap between the electrodes is reduced to about 5 kV by arc discharge. Further, the pulse modulator 3 2 is provided with a power regulator 3 4 and a wattmeter 3 6, and the supplied power can be freely adjusted, and the test described later is performed in order to maintain the arc discharge potential. Is set in a range of 1 0 0 W to 5 0 0 W.
本発明に係るペンジヱット型プラズマ処理装置おいて、 P t · R h系金属から なる電極先端部 1 0の直径が約 1 . 6 mm (電極先端面 1 0 aの断面積：約 2 m m 2) であり、 前記パルス周波数が約 3 0 k H z、 前記パルス幅が約 2 μ s、 供 給される作動ガスの流量が約 2 0 L /'m i ηである場合、 前記供給電力が以下の 値に設定されるとき、 アーク放電により好適なプラズマを連続的又は間欠的に生 成することができる。 この場合、 平均電力が 2 0 O W ( 1 0 O W/mm 2) 以下 、 最大印加電圧が約 5 k V、 最大ピーク電流が 1 0 A ( 5 A/mm 2) 以下に設 定されることが好ましい。 換言すれば、 供給される電流の平均電流密度が所定値 以下に設定されることが好ましく、 前記断面積を大きくすれば、 供給電力を増大 させ、 プラズマの生成量を増大させることができる。 即ち、 前記平均電力の密度 を 1 0 ow. zmm 2以下に設定すれば、 前記断面積に応じてプラズマの生成量を 適宜に調整することができる。 In the pendant plasma processing apparatus according to the present invention, the diameter of the electrode tip portion 10 made of Pt · Rh-based metal is about 1.6 mm (cross-sectional area of the electrode tip surface 10 a: about 2 mm 2 ). When the pulse frequency is about 30 kHz, the pulse width is about 2 μs, and the flow rate of the supplied working gas is about 20 L / 'mi η, the supplied power is When set to a value, a suitable plasma can be generated continuously or intermittently by arc discharge. In this case, the average power may be set to 20 OW (10 OW / mm 2 ) or less, the maximum applied voltage is set to about 5 kV, and the maximum peak current is set to 10 A (5 A / mm 2 ) or less. preferable. In other words, the average current density of the supplied current is preferably set to a predetermined value or less, and if the cross-sectional area is increased, the supplied power is increased. The amount of plasma generated can be increased. That is, if the density of the average power is set to 10 ow.z mm 2 or less, the plasma generation amount can be appropriately adjusted according to the cross-sectional area.
また、 図 3は本発明に係る両電極水冷ペンジエツト型電極を有するプラズマ生 成装置 7の断面概略図であり、 電極基端部 1 2の外周に水冷部 1 5が設けられて いる。 尚、 図 1と同一の部材に関しては、 符号及びその説明を一部省略する。 冷 却水 1 5 aを循環させることにより電極基端部 1 2と共に電極先端部 1 0が冷却 され、 電極材料の蒸発が抑制されて電極の損耗量を低減化できる。 従って、 長時 間に亘つてプラズマ Pを生成することができる。 更に、 前記電極先端面近傍の外 周からプラズマが発生することや電極材料が蒸発することを防止することができ 、 好適なジェット状のプラズマ Pが生成される。 また、 プラズマ Pの射出量に応 じて冷却水 1 5 a、 1 8 aの流量及び./又は温度を調整し、 プラズマ生成装置 7 の長時間に亘る安定した動作を実現することができる。 更に、 前記水冷部 1 5を 電極先端面 1 0 aに近付ければ、 前記電極先端面 1 0 aの外縁周辺も冷却されて プラズマの拡散が抑制され、 生成されるプラズマ Pの流束を絞ることが可能であ る。  FIG. 3 is a schematic cross-sectional view of a plasma generating apparatus 7 having a double-electrode water-cooled pendant electrode according to the present invention, and a water-cooled portion 15 is provided on the outer periphery of the electrode base end portion 12. For the same members as those shown in FIG. By circulating the cooling water 15a, the electrode base end portion 12 and the electrode tip end portion 10 are cooled, and evaporation of the electrode material is suppressed, so that the amount of electrode wear can be reduced. Therefore, plasma P can be generated over a long period of time. Furthermore, it is possible to prevent the generation of plasma from the outer periphery in the vicinity of the electrode tip surface and the evaporation of the electrode material, and a suitable jet plasma P is generated. In addition, the flow rate and / or temperature of the cooling water 15 a and 18 a can be adjusted according to the injection amount of the plasma P, and the plasma generator 7 can be operated stably for a long time. Furthermore, if the water cooling part 15 is brought close to the electrode tip surface 10Oa, the periphery of the outer edge of the electrode tip surface 1Oa is also cooled, so that plasma diffusion is suppressed and the flux of the generated plasma P is reduced. It is possible.
図 4は、 本発明に係る電極先端部 1 0の断面概略図である。 図 1では、 電極先 端部 1 0全体が P t · R h系金属から形成されているが、 （4 A) に示すように 、 前記電極先端部本体 1 0 cにメツキコート、 蒸着等により P t · R h系金属の コーティング膜 1 0 bを形成して電極先端部を構成することができる。 P t - R h合金は、 一般に、 P t純金属に比べ高価であり、 P t— R h合金の使用量を削 減することにより、 本発明に係るプラズマ生成用電極の製造コストを低減化する ことができる。 コーティング膜 1 0 bが比較的 R hを多量に含有する P t - R h 合金から形成され、 前記電極先端部本体 1 0 cが P t金属から構成される場合、 金属元素の拡散により界面及び界面近傍に P t — R h合金が形成される。 電界が 集中する電極先端面 1 0 aに被膜されるコーティング膜 1 0 bの厚さ T 2は、 側 面のコーティング膜 i 0 bの厚さ 1 より厚く被膜されることが好ましい。 また 、 （4 B ) に示すように、 放電表面を含む所定領域にのみコーティング膜 1 0 b を形成しても良い。 厚さ T。は、 0 . 1 mm以上であることが好ましく、 0 . 5 mm以上であることがより好ましい。 FIG. 4 is a schematic cross-sectional view of the electrode tip 10 according to the present invention. In FIG. 1, the entire tip 10 of the electrode tip is formed of a Pt · Rh-based metal. However, as shown in (4A), the electrode tip portion 10c is formed by P coating or vapor deposition. The tip of the electrode can be formed by forming a coating film 10 b of t · Rh-based metal. P t-R h alloy is generally more expensive than P t pure metal, and reducing the amount of P t—R h alloy used reduces the manufacturing cost of the plasma generating electrode according to the present invention. can do. When the coating film 10b is formed of a Pt-Rh alloy containing a relatively large amount of Rh, and the electrode tip body 10c is made of Pt metal, the interface and A P t — R h alloy is formed near the interface. The thickness T 2 of the coating film 10 b coated on the electrode tip surface 10 a where the electric field concentrates is preferably thicker than the thickness 1 of the coating film i 0 b on the side surface. Further, as shown in (4 B), the coating film 10 b may be formed only in a predetermined region including the discharge surface. Thickness T. Is preferably 0.1 mm or more, 0.5 More preferably, it is at least mm.
図 5は、 本発明に係る P t. · R h系金属製電極先端部と比較例の P t— I r合 金製の各電極先端部をアーク放電後に撮像した電極先端部の拡大写真図である。 図 1示した電極先端部 1 0の電極材料として、 本発明に係る P t一 R h合金、 比 較例として P t _ I r合金が用いられている。 1 0分間アーク放電によるプラズ マ生成を行った後、 前記電極先端面 1 0 aを拡大撮像している。 用いられた各電 極先端部の直径は約 1 . 6 mmであり、 電極先端面 1 0 aの表面積は同一である 。 電極材料として用いられた P t一 R h合金の R h含有量は 1 0重量％であり、 P t— I r合金の I r含有量は 2 0重量％である。 P t一 R h合金製電極先端部 を用いた場合には、 前記パルスモジユレータに 5 0 0 Wの電力が供給され、 P t 一 I r合金製の電極先端部を用いた場合には、 4 0 0 Wの電力が供給されている 。 また、 作動ガスとして乾燥空気を用いている。  Fig. 5 is an enlarged photograph of the tip of the Pt.Rh-based metal electrode according to the present invention and the electrode tip of each of the Pt-Ir alloy electrodes of the comparative example taken after arc discharge. It is. As the electrode material of the electrode tip 10 shown in FIG. 1, a Pt—Rh alloy according to the present invention is used, and a Pt_Ir alloy is used as a comparative example. After performing plasma generation by arc discharge for 10 minutes, the electrode tip surface 10a is magnified. The diameter of each electrode tip used was about 1.6 mm, and the surface area of the electrode tip face 10a was the same. The Rt content of the Pt-Rh alloy used as the electrode material is 10% by weight, and the Ir content of the Pt—Ir alloy is 20% by weight. When using the electrode tip of Pt 1 Rh alloy, power of 500 W is supplied to the pulse modulator, and when using the electrode tip of Pt 1 Ir alloy, 4 00 W power is being supplied. Dry air is used as the working gas.
( 5 A) に示すように、 P t—R h合金製の電極先端部を用いた場合、 供給電 力が 5 0 0 Wの場合において、 電極先端部の形状は放電前とほぼ同じ形状を有し ている。 （ 5 B ) に示すように、 P t— I r合金製の電極先端部を用いた場合に は、 供給電力 4 0 O Wにおいて、 電極先端部の形状に顕著な変形が見られる。 こ れは、 電極先端がイオン衝突等により加熱されて融解すると共に、 金属蒸発、 酸 化損耗、 火花損耗等によって電極損耗が増大したものと思料される。 （5 A) に 示すように、 本発明に係る P t— R h合金製電極先端部は、 電極損耗が殆ど無く 、 損耗材料粒子の放出が極めて低減化されており、 P t— R h合金を用レ、たプラ ズマ生成用電極では、 高電圧を印加して高エネルギーのアークプラズマを高効率 に生成できることを示している。  As shown in (5 A), when the electrode tip made of P t—R h alloy is used, the shape of the electrode tip is almost the same as before the discharge when the supply power is 500 W. Have. As shown in (5B), when an electrode tip made of a Pt—Ir alloy is used, a remarkable deformation is seen in the shape of the electrode tip at a supplied power of 40 OW. This is thought to be due to the fact that the electrode tip was heated and melted by ion bombardment and the like, and the electrode wear increased due to metal evaporation, oxidation wear, spark wear, and the like. As shown in (5 A), the electrode tip made of the P t—R h alloy according to the present invention has almost no electrode wear, and the release of wear material particles is extremely reduced. This shows that the plasma generating electrode can generate high-energy arc plasma with high efficiency by applying a high voltage.
図 6には、 本発明に係る P t金属製電極先端部をプラズマ生成後に撮像した拡 大写真図を示し、 図 Ίには、 比較例である P t— I r合金 （ 7 A) 及び P t— W 合金 （7 B ) 力 らなる各電極先端部の放電後の拡大写真図を示す。 図 6及び図 7 の結果は、 供給電力が 3◦ O Wでアーク放電を 1 0分間行ったものである。 また 、 各電極先端部の直径は約 1 . 6 mm, 長さは 9 mmである。 （6 A；) 、 ( 6 B ) に示すように、 本発明に係る P t金属製電極は、 良好な耐酸化性を有し、 ブラ ズマ生成後も電極先端部の表面は、 放電前と同じ形状を有している。 また、 （6 O C) に示す走査型電子顕微鏡像 （S E M像） においても微細孔が僅かに形成され ているが、 略放電前の表面状態を保持している。 Fig. 6 shows an enlarged photograph of the Pt metal electrode tip according to the present invention imaged after plasma generation. Fig. 6 shows the P t—Ir alloy (7A) and P as comparative examples. An enlarged photograph after discharge of each electrode tip composed of t—W alloy (7 B) force is shown. The results in Fig. 6 and Fig. 7 are the results of arc discharge for 10 minutes with the supplied power of 3 ° OW. Each electrode tip has a diameter of about 1.6 mm and a length of 9 mm. As shown in (6A;) and (6B), the Pt metal electrode according to the present invention has good oxidation resistance, and the surface of the tip of the electrode after the generation of the plasma is Have the same shape. Also, (6 O In the scanning electron microscope image (SEM image) shown in C), micropores are slightly formed, but the surface state before the discharge is maintained substantially.
一方、 （ 7 A) に示すように、 P t — I r合金 （ I r含有量： 2 0重量％) か ら形成される電極先端部の場合、 貴金属に共通する良好な耐酸化性を有するが、 放電前と比べて形状が変化している。 即ち、 P t金属を用いた場合に比べ、 P t - I r合金は損耗量が大きく、 前述のように、 供給電力及び放電時間の増大に伴 つて電極損耗が急激に増大する。 更に、 （7 B ) に示すように、 P t— W合金製 電極先端部の場合、 3 0 0 Wで 1 0分間の放電することにより、 著しい変形が引 起されている。 これは、 酸化タングステンの形成による電気抵抗の増加に伴って 、 放電表面におけるジュール熱発生の大幅な増大が要因の 1つとして考えられる 。 また S E M像から、 Wの含有によつて電極材料の耐酸化性が低下して放電表面 が脆くなり、 損耗材料粒子が多量に放出されていることが分かる。  On the other hand, as shown in (7A), in the case of an electrode tip formed from a Pt—Ir alloy (Ir content: 20% by weight), it has good oxidation resistance common to noble metals. However, the shape has changed compared to before discharge. That is, compared to the case where Pt metal is used, the Pt-Ir alloy has a large amount of wear, and as described above, the electrode wear increases rapidly as the supply power and the discharge time increase. Furthermore, as shown in (7B), in the case of the electrode tip portion made of Pt—W alloy, significant deformation was caused by discharging at 30 W for 10 minutes. This is thought to be due to a significant increase in Joule heat generation on the discharge surface as the electrical resistance increases due to the formation of tungsten oxide. From the SEM image, it can be seen that the inclusion of W lowers the oxidation resistance of the electrode material, making the discharge surface brittle and releasing a large amount of wear material particles.
次に、 本発明に係る P t金属製電極先端部及び図 5に示した各電極先端部を用 いて、 供給電力に対する電極損耗を定量的に測定した結果を示す。 図 8は、 本発 明に係る P t金属及び P t— R h合金の電極先端部と比較例の P t— I r合金電 極先端部を用いた電極損耗量の電 依存性を示すダラフ図である。 横軸は供給さ れる電力 （Electric power (W) ) 、 縦軸は偵耗量 (Erosion amount (m g ) ) を示し、 放電時間 （Discharge duration time) を 1 0分間に設定して、 プラズ マ生成前後における電極先端部の質量差から損耗量が見積もられている。 この実 験では、 図 3に示した両電極水冷ペンジェット型のブラズマ生成装置が用いられ ている。 図 8に示すように、 供給電力が 1 0 0 W〜3 0 0 Wの範囲において、 P t - R h合金製の電極先端部の場合、 電極損耗は殆ど無いか若しくは極めて微量 に抑制され、 3 0 0 W〜 5 0 0 Wの範囲においても電極損耗の増大が抑制され、 損耗量の僅かな増加が見られるだけである。 従って、 P t.—R h合金を電極材料 として用いることにより、 損耗材料粒子の混入が格段に少ない高エネルギーで高 純度のプラズマを安定して生成できることを示している。  Next, the results of quantitative measurement of electrode wear with respect to the supplied power using the Pt metal electrode tip according to the present invention and each electrode tip shown in FIG. 5 are shown. Figure 8 is a graph showing the electrical dependence of electrode wear using the electrode tip of the Pt metal and Pt—Rh alloy according to the present invention and the Pt—Ir alloy electrode tip of the comparative example. FIG. The horizontal axis shows the supplied power (Electric power (W)), the vertical axis shows the amount of retirement (Erosion amount (mg)), and the discharge duration (Discharge duration time) is set to 10 minutes. The amount of wear is estimated from the mass difference between the front and rear electrode portions. In this experiment, the double-electrode water-cooled pen jet type plasma generator shown in Fig. 3 is used. As shown in FIG. 8, in the case where the power supply is in the range of 100 W to 300 W, in the case of an electrode tip made of a Pt-Rh alloy, there is almost no electrode wear or a very small amount of electrode wear, Even in the range of 300 W to 500 W, an increase in electrode wear is suppressed, and only a slight increase in wear is observed. Therefore, it is shown that by using Pt.-Rh alloy as an electrode material, high-energy and high-purity plasma can be stably generated with much less contamination of wear material particles.
P t金属製電極先端部の場合、 供給電力が 3 0 0 Wまでは、 殆ど損耗しないか 若しくは損耗量が極めて微少な量に抑制されている。 供給電力が 4 0 0 Wになる と急激な損耗量の増大が見られ、 高エネルギーで高純度のアークプラズマを生成 する場合には電極材料としては不適当である。 しかしながら、 図 6は、 供給電力 が 40 OW以下である場合には、 P t金属が優れた電極材料であることを示して いる。 In the case of the tip of the Pt metal electrode, the supplied power is hardly worn up to 300 W, or the amount of wear is suppressed to a very small amount. When the supplied power reaches 400 W, the amount of wear increases rapidly, generating high-energy, high-purity arc plasma. In this case, it is not suitable as an electrode material. However, Figure 6 shows that Pt metal is an excellent electrode material when the power supply is 40 OW or less.
—方、 P t _ I r合金製電極先端部の場合、 30 OWで既に損耗量の顕著な増 大が見られ、 供給電力が 400Wになると損耗量は急激に増大している。 更に、 -On the other hand, in the case of the electrode tip made of Pt_Ir alloy, the amount of wear has already increased remarkably at 30 OW, and the amount of wear has increased rapidly when the power supply reaches 400W. Furthermore,
40 OWを越えると電極としての機能自体が低下する傾向にあり、 50 OWでの 測定は行っていない。 即ち、 P t— I r合金製電極先端部では、 供給電力が 30 0Wになると明らかな損耗量の増加が見られ、 300Wを越えた範囲で電極損耗 が急激な増加傾向を示しており、 P t— I r合金を電極材料として用いることは 困難であることを示している。 なお、 逆に言えば、 プラズマへの供給電力が 30 0W以下であれば、 P t— I r電極も利用可能である。 If it exceeds 40 OW, the electrode function itself tends to deteriorate, and measurement at 50 OW is not performed. That is, at the tip of the electrode made of P t—I r alloy, when the power supplied reaches 300 W, the amount of wear increases clearly, and the electrode wear tends to increase rapidly in the range exceeding 300 W. This shows that it is difficult to use t—Ir alloys as electrode materials. Conversely, if the power supplied to the plasma is 300 W or less, a Pt—Ir electrode can also be used.
図 9は、 本発明に係るプラズマ処理装置によりブラズマ処理された被処理物表 面の光学顕微鏡写真図である。 被処理物には、 S i基板が用いられ、 光学顕微鏡 によりブラズマ処理後の S i基板表面の喑視野像を撮像したものであり、 （ 9 A ) は、 未処理基椒 (Unprocessed substrate, Untreated substrate) の表 it]を している。 P t—Rh合金のプラ^;'マ生成用電極を具備するプラズマ処理装置を 用いた場合、 （9B) 及び （9C) に示すように、 供給電力 100Wと 200W では、 損耗材料粒子が殆ど付着しておらず、 （9A) の未処理基板表面と同様の 状態であることが分かる。 更に、 供給電力を 200Wから 400Wに増加させて いった場合、 （9D) と （9E) に示すように、 僅かに損耗材料粒子が付着する のみである。 （9F) 〜 （9H) に示した本発明に係る P t金属のプラズマ生成 用電極を用いた場合と比べ、 極めて損耗材料粒子の付着が少ないことが分かる。 本発明に係るプラズマ処理装置に P t金属製電極先端部を用いた場合、 （ 9 F ) に示すように、 供給電力 200Wでは、 殆ど損耗粒子が付着されておらず、 （ 9 G) に示す供給電力 300Wの場合においても、 微量な損耗材料粒子が S i基 板表面全体に付着しているだけである。 更に、 （9H) に示す供給電力 400W の場合では、 P t金属からなる比較的大きな損耗材料粒子が電極から放出され、 FIG. 9 is an optical micrograph of the surface of an object to be processed that has been subjected to plasma processing by the plasma processing apparatus according to the present invention. An Si substrate is used as the object to be processed, and a vaginal field image of the surface of the Si substrate after the plasma processing is taken with an optical microscope. (9 A) is an unprocessed substrate, Untreated table)]]. When using a plasma processing device equipped with a Pt—Rh alloy plasma generation electrode, as shown in (9B) and (9C), almost no wear material particles adhere to the supply power of 100W and 200W. It can be seen that it is in the same state as the untreated substrate surface in (9A). Furthermore, when the power supply is increased from 200W to 400W, only slightly worn material particles adhere as shown in (9D) and (9E). Compared to the case of using the Pt metal plasma generation electrode according to the present invention shown in (9F) to (9H), it can be seen that there is very little attachment of wear material particles. When a Pt metal electrode tip is used in the plasma processing apparatus according to the present invention, as shown in (9 F), almost no wear particles are attached at a power supply of 200 W, as shown in (9 G) Even when the power supply is 300 W, a small amount of wear material particles are only attached to the entire surface of the Si substrate. Furthermore, in the case of the supply power of 400 W shown in (9H), relatively large wear material particles made of Pt metal are released from the electrode,
5 i基板表面全体に付着していることが分かる。 図 8に示した結果と良い一致を 示しており、 P t金属製電極先端部が供給電力 300 W程度までは、 損耗材料粒 子の放出が抑制され、 極めて優れたプラズマ生成用電極として利用できることを 示している。 . 5 It can be seen that it adheres to the entire surface of the i substrate. This shows good agreement with the results shown in Fig. 8. As a result, it is shown that it can be used as an extremely excellent plasma generation electrode. .
次に、 本発明に係る P t金属及び P t— R h合金 （R h含有量： 1 0重量％) のデータに比較例として、 W金属、 C u金属、 P t— I r合金 （I r含有量： 2 0重量％) 、 ー^^合金 （W含有量： 8重量％) のデータを加え、 電極損耗量 の放電時間依存性を比較した結果を示す。 図 1 0は、 本発明に係る P t · R h系 金属製と比較例である各種金属からなる電極先端部の積算放電時間 （  Next, as a comparative example to the data of Pt metal and Pt—Rh alloy (Rh content: 10% by weight) according to the present invention, W metal, Cu metal, Pt—Ir alloy (I r content: 20% by weight) and-^^ alloy (W content: 8% by weight) data are added to show the results of comparing the discharge time dependence of electrode wear. Fig. 10 shows the cumulative discharge time at the tip of an electrode made of Pt · Rh-based metal according to the present invention and various types of metals as comparative examples (
Accumulated discharge time [m i n ) ) に对 ■。積算 ¾¾耗直 (Accumulated erosion amount (m g ) ) を示すグラフ図である。 図 3示した両電極水冷ペンジ ュット型プラズマ生成装置に上記電極材料から形成される電極先端部を用いて、 放電時間毎の電極損耗量が測定され、 それらの値がプロットされている。 この測 定において供給電力は、 3 0 0 Wに設定されている。 また、 各電極先端部の直径 は、 全て約 1 . 6 mmであり、 同一の先端表面積を有している。 Accumulated discharge time [m i n)) vs. ■. FIG. 4 is a graph showing an accumulated erosion amount (mg). Using the electrode tip formed from the above electrode material in the double-electrode water-cooled pendant plasma generator shown in Fig. 3, the amount of electrode wear for each discharge time was measured, and these values were plotted. In this measurement, the power supply is set at 300 W. The diameter of each electrode tip is about 1.6 mm, and has the same tip surface area.
図 1 0に示すように、 P t— R h合金の電極先端部では、 長時間の放電に対し ても損耗量が極めて微量に抑制されている。 6 0分間の放電で P t一 P h合金製 電極先端部の損耗量は約 0 . 6 m g程度であり、 他の金属に比べ格段の差がある 。 P t金属製電極先端部では、 比較例の金属に比べ損耗量の増大が抑制されてお り、 6 0分間の放電で損耗量が約 2 . 4 m g程度となっている。  As shown in FIG. 10, at the electrode tip of the Pt—Rh alloy, the amount of wear is suppressed to a very small amount even for a long discharge. The amount of wear at the tip of the Pt-Ph alloy electrode after about 60 minutes of discharge is about 0.6 mg, which is much different from other metals. In the tip part of the Pt metal electrode, an increase in the amount of wear is suppressed compared to the metal of the comparative example, and the amount of wear is about 2.4 mg after 60 minutes of discharge.
一方、 P t— I r合金製電極先端部では、 損耗量が 2 . 9 m g程度に達してい る。 また、 C u金属では損耗量が 3 0分間の放電で既に 2 . 4 m g程度に達し、 W金属や P t— W合金の場合、 5分間の放電に対して、 W金属で約 5 0 m g程度 、 P t— W合金で約 7 m g程度の損耗量となっている。 P t金属とその合金であ る P t— R h合金、 P t— I r合金、 P t _W合金を対比した場合、 R hを含有 することによりプラズマ生成用電極の安定性が格段に向上し、 I rや Wと合金を 形成する場合、 電極性能が低下していることが分かる。  On the other hand, at the tip of the electrode made of Pt-Ir alloy, the amount of wear reaches about 2.9 mg. In Cu metal, the amount of wear has already reached about 2.4 mg after 30 minutes of discharge, and in the case of W metal and Pt—W alloy, about 50 mg of W metal for 5 minutes of discharge. About 7 mg of Pt—W alloy is worn out. When Pt metal and its alloys, Pt—Rh alloy, Pt—Ir alloy, and Pt_W alloy are compared, the stability of the plasma generation electrode is greatly improved by containing Rh. In addition, when forming an alloy with Ir and W, it can be seen that the electrode performance deteriorates.
図 1 1は、 本発明に係る P t一 R h合金を電極材料として用いたプラズマ生成 用電極における積算損耗量 （Accumulated wear amount (ni g ) ) の積算放電時 間 Accumulated discharge time (m i n ) ) 依存性を示すグラフ図であり、 P t一 R h合金の R h含有量を変化させ、 電極の損耗量が測定されている。 この実 験は、 図 3に示した両電極水冷ペンジェット型プラズマ生成装置が用いられ、 よ り長時間に亘る損耗量を比較されている。 前記 P t— Rh合金における Rhの質 量比率が 10%場合を丸印 （〇） 、 20%の場合を三角 （厶） 、 30%の場合を 四角 （口） で示している。 供給電力は 300W、 各電極先端部の直径は、 比較例 である P t製電極 （♦) を含めて、 全て約 1. 6mmに設定されている。 尚、 図 10と同様に、 放電時間毎の損耗量が測定され、 それらを積算した値がプロット されている。 Figure 11 shows the cumulative discharge time (Accumulated wear amount (ni g)) of the plasma generation electrode using the Pt-Rh alloy according to the present invention as the electrode material. It is a graph showing the dependence, and the wear amount of the electrode is measured by changing the Rh content of the Pt-Rh alloy. This fruit In the experiment, the double electrode water-cooled pen jet type plasma generator shown in Fig. 3 was used, and the amount of wear over a longer time was compared. When the mass ratio of Rh in the Pt—Rh alloy is 10%, it is indicated by a circle (◯), when it is 20% by a triangle (厶), and when it is 30% by a square (mouth). The supplied power is 300W, and the diameter of each electrode tip is set to about 1.6mm, including the Pt electrode (♦), which is a comparative example. As in Fig. 10, the amount of wear for each discharge time is measured, and the total value is plotted.
図 1 1に示すように、 P t—Rh合金の Rh含有量が増大するに伴って電極の 損耗量が低減しており、 R hの質量比率が 30 %の場合には、 P t製電極に比べ て損耗量が約 1ノ'2程度まで低減されている。 換言すれば、 プラズマ生成用電極 の寿命が約 2倍になると共に、 不純物の発生も半分程度まで抑制されており、 R h含有量を増大させることによって、 より好適なブラズマ生成用電極が得られて レ、る。 尚、 P t金属製電極先端部は、 P t— Rh合金を用いた場合に比べ積算損 耗量が大きくなつているが、 図 10に示した他の金属に比べ、 積算損耗量の増大 が僅かであることは云うまでもない。  As shown in Fig. 11, as the Rh content of the P t-Rh alloy increases, the wear amount of the electrode decreases, and when the Rh mass ratio is 30%, the Pt electrode Compared with, the amount of wear has been reduced to about 1'2. In other words, the life of the plasma generating electrode is approximately doubled and the generation of impurities is suppressed to about half, and a more suitable plasma generating electrode can be obtained by increasing the Rh content. T The tip of the Pt metal electrode has a larger amount of accumulated wear than when the Pt-Rh alloy is used, but the amount of accumulated wear increases compared to the other metals shown in Fig. 10. Needless to say, it is slight.
尚、 前記電極材料の機械的強度に関する試験では、 Rhの質量比率が 40%よ り大きくなるとプラズマ生成用電極の機械的強度が顕著に低下する結果が得られ ている。 即ち、 Rhの質量比率が 1〜40%の範囲に設定されることにより、 本 発明に係るプラズマ生成用電極に好適な硬度、 引張り強度ゃ靱性などが付与され る。 更に、 機械的強度に関する上記の試験では、 Rhの質量比率が 10〜30% に設定される場合に、 より好適な機械的強度が得られている。  In the test on the mechanical strength of the electrode material, the mechanical strength of the plasma generating electrode is remarkably lowered when the mass ratio of Rh exceeds 40%. That is, when the mass ratio of Rh is set in the range of 1 to 40%, suitable hardness, tensile strength, toughness, and the like are imparted to the plasma generating electrode according to the present invention. Furthermore, in the above-described test on mechanical strength, more suitable mechanical strength is obtained when the mass ratio of Rh is set to 10 to 30%.
本発明者等は、 p t · Rh系金属がプラズマ生成用電極の電極材料として、 優 れた特性を有することを金属のより本質的な物性に基づいて解明するため、 本発 明に係る P t - Rh系金属の種々の物性値を測定し、 電極性能との対応関係から 、 好適な物性値を特定している。 以下に、 P t · Rh系金属に関する各種物性値 の測定結果を示す。  In order to elucidate that pt · Rh-based metals have excellent characteristics as electrode materials for plasma generation electrodes based on the more essential physical properties of metals, the present inventors -Various physical property values of Rh-based metals are measured, and appropriate physical property values are identified from the correspondence with electrode performance. The measurement results of various physical properties related to Pt · Rh metals are shown below.
本発明者等は、 本発明に係る P t · Rh系金属が電極材料に好適である要因と して格子定数に着目し、 X線回折 （XRD) 分析から P t ' Rh系金属の格子定 数を導出している。 図 12は、 本発明に係る P t · Ph系金属の XRD分析の結 果を示すグラフ図である。 図の各データは、 〇&の1 0；線 （ぇ=1. 54060 A) 照射による回折角 2 Θに対する X線回折強度 （Intensity) を示しており、 それぞれ、 P t金属 （P t) 、 Rhを 10重量。/。含有する P t— R h合金 （ P t - R h 10 %) 、 R hを 20重量0 /o含有する P t— R h合金 （ P t— R h 20 % ) 及び Rhを 30重量％含有する P t— Rh合金 （P t—Rh 30%) の X線回 折強度グラフを示している。 実験では、 図 1 2の破線内にある P t · Rh系金属 の （1 1 1) 面に対応する XRDの回折角 2 Θから面間隔 dを算出し、 格子定数 aを求めている。 図 13には、 図 12の破線内を拡大したグラフ図を示しており 、 本発明に係る P t . Rh系金属の格子定数が Rhの含有量に応じて明確に変化 していることがわかる。 尚、 図示しないが、 Rhのバルタ金属を用いた XRM分 析も行っている。 The present inventors focused on the lattice constant as a factor that makes the Pt · Rh metal according to the present invention suitable as an electrode material, and based on the X-ray diffraction (XRD) analysis, the lattice constant of the Pt'Rh metal was determined. The number is derived. Fig. 12 shows the result of XRD analysis of the Pt · Ph metal according to the present invention. It is a graph figure which shows a fruit. Each data in the figure shows X-ray diffraction intensity (Intensity) with respect to diffraction angle 2 Θ by irradiation of 〇 & 1 0; line (H = 1.54060 A), P t metal (P t), Rh 10 weight. /. Contains Pt—Rh alloy (Pt-Rh 10%), Rh contains 20 weight 0 / o Pt—Rh alloy (Pt—Rh 20%) and Rh contains 30% by weight The X-ray diffraction strength graph of the P t—Rh alloy (P t—Rh 30%) is shown. In the experiment, the lattice constant a is obtained by calculating the interplanar distance d from the XRD diffraction angle 2Θ corresponding to the (1 1 1) plane of the P t · Rh group metal in the broken line in Fig. 12. FIG. 13 is an enlarged graph showing the inside of the broken line in FIG. 12, and it can be seen that the lattice constant of the P t .Rh metal according to the present invention clearly changes according to the Rh content. . Although not shown, XRM analysis using Rh Balta metal is also performed.
表 1には、 前記 Rh'の重量。 /0 (Weight Percent of Rli) と前記 XRD分析から求 めた格子定数 a (Lattice Constant) を実施例 1〜 4として記載している。 比較例 として示した Rh金属 （表中の Rh 100重量％) は、 加工性が悪く、 電極材料 として用いることが困難である。 即ち、 表 1における格子定数 aが 3. 797 A 以上となると、 電極材料の加工性が低下し、 プラズマ生成用電極として利用する ことが困難であることを示している。 本発明者等は、 前記電極材料の加工性に関 する R h含有量の依存性から電極材料として好ましい金属の格子定数 aを 3. 8 0以上と判断している。 Table 1 shows the weight of Rh ′. Examples 1 to 4 describe / 0 (Weight Percent of Rli) and lattice constant a (Lattice Constant) obtained from the XRD analysis. The Rh metal shown as a comparative example (Rh 100% by weight in the table) has poor processability and is difficult to use as an electrode material. That is, when the lattice constant a in Table 1 is 3.797 A or more, the workability of the electrode material is lowered, which indicates that it is difficult to use it as an electrode for plasma generation. The present inventors have determined that the lattice constant a of a metal preferable as an electrode material is 3.80 or more from the dependence of the Rh content on the workability of the electrode material.
[表 1 ]  [table 1 ]
Rt'Rh系金属に占める Rhの重量％と格子定数 a(A)
Figure imgf000029_0001
例えば、 Cu金属の格子定数は、 約 3. 608Aであり、 W金属の格子定数は 約 3. 158Aである力 図 10に示したように、 Cu金属や W金属は、 プラズ マ生成用電極に用いた場合、 損耗量が多量であった。 従って、 電極材料の格子定 数が 3. 80 Aより小さくなると加工性が悪化するだけでなく、 損耗粒子の発生 にも寄与する可能性が大きい。 更に、 一般的に、 金属の格子定数が大きくなると 不純物が固溶し易くなるため、 前記電極材料の格子定数は、 Pい金属 （表 1中の 尺110重量％) の格子定数 （約 3. 92 A) より小さいことが好ましレ、。 即ち、 本発明に係る P t · R h系金属は、 格子定数 aを 3. 80A〜3. 92 Aの範囲 に設定することが好ましく、 3. 87A〜3. 92 Aの範囲に設定することがよ り好ましい。 更に、 P t · Rh系金属に他の金属元素を添加する場合においても 、 格子定数 aを 3. 80A〜3. 92 Aの範囲に設定することにより、 好適な電 極材料として用いることができる。 Rt% of Rt'Rh metal and lattice constant a (A)
Figure imgf000029_0001
For example, the lattice constant of Cu metal is about 3.608A, and the lattice constant of W metal is about 3.158A. As shown in Fig. 10, Cu metal and W metal are used as plasma generation electrodes. When used, the amount of wear was large. Therefore, the lattice constant of the electrode material When the number is smaller than 3.80 A, not only the workability deteriorates but also the possibility of contributing to the generation of wear particles is high. Furthermore, generally, as the lattice constant of a metal increases, impurities easily dissolve, so the lattice constant of the electrode material is the lattice constant (about 3.3% by weight in Table 1) of P metal (approximately 3. 92 A) It is preferable to be smaller. That is, in the Pt · Rh-based metal according to the present invention, the lattice constant a is preferably set in the range of 3.80 A to 3.92 A, and is set in the range of 3.87 A to 3.92 A. Is more preferable. Furthermore, even when another metal element is added to the Pt · Rh-based metal, it can be used as a suitable electrode material by setting the lattice constant a in the range of 3.80 A to 3.92 A. .
図 14は、 本発明に係る P t · Rh系金属の Rh含有量 （重量％) に対する格 子定数を示すグラフ図である。 図 1 3に示した XRD分析によって求めた格子定 数 aを Rh含有量 （Weight Percent of Rh) に対してプロッ卜しており、 以下に 示すように、 格子定数 aを R h含有量の関係を近似的に導出している。 実線で示 す線形関数は、 プロットしたデータに対するフイツティング関数であり、 最小二 乗法により最適化が行われている。 更に、 実験値の誤差範囲から求めた格子定数 の上限値を一点鎖線の線形関数で示し、 下限値を二点鎖線の線形関数で示してい る。 即ち、 誤差範囲を含めた場合、 前記 Rh含有量を 重量％として、 この Rh 含有量と格子定数 aの関係を示す a— X関係式は、 次のように表される。  FIG. 14 is a graph showing the lattice constant with respect to the Rh content (% by weight) of the Pt · Rh metal according to the present invention. The lattice constant a obtained by the XRD analysis shown in Fig. 13 is plotted against the Rh content (Weight Percent of Rh). As shown below, the lattice constant a is related to the Rh content. Is approximately derived. The linear function shown by the solid line is a fitting function for the plotted data, and is optimized by the least square method. Furthermore, the upper limit value of the lattice constant obtained from the error range of the experimental value is indicated by a one-dot chain line linear function, and the lower limit value is indicated by a two-dot chain line linear function. In other words, when the error range is included, the Rh content is weight%, and the a-X relational expression indicating the relationship between the Rh content and the lattice constant a is expressed as follows.
a =- 0. 001 1 3 X+ 3. 908±0. 02  a =-0. 001 1 3 X + 3. 908 ± 0.02
前述のように、 格子定数 aを所望の範囲内に設定することにより、 好適な電極材 料を得ることができる。 上記 a— X関係式を用いて Rhの含有量を調整又は選択 すれば、 本発明に係る P t · R.h系金属の格子定数を所望の範囲内に設定できる から、 加工性の良い電極材料を得ることができる。 従って、 この電極材料を用い て、 高耐久性のブラズマ生成用電極を容易に製造することができる。 As described above, a suitable electrode material can be obtained by setting the lattice constant a within a desired range. If the Rh content is adjusted or selected using the above a—X relational expression, the lattice constant of the Pt · Rh-based metal according to the present invention can be set within a desired range. Obtainable. Therefore, using this electrode material, a highly durable plasma generating electrode can be easily manufactured.
図 15は、 本発明に係る電極材料である P t— R h合金の状態図である。 縦軸 は温度 （°C) 、 横軸は P tに対する Rhの含有量 （重量。 /0) を示し、 曲線 Aは固 相線、 曲線 Bは液相線、 曲線 Cは溶解度線を示している。 この状態図は、 前述の THE PGM DATABASE"http://www. platinunimetalsreview. com/jnipgm/index. js 非特許文献 2) に記載されるデータを引用したものである。 状態 （1) は、 P t と R hは均一融液状態であり、 曲線 Aと曲線 Bの間では、 液相と固相の混合状態 となっている。 低温側の状態.（2) は、 完全固溶体状態を示し、 固溶度限である 曲線 Cより低温側の状態 （ 3 ) は、 P tを主成分として R hが固溶及び Z又は晶 出した P t相と R hを主成分として P tが固溶及び/又は晶出した R h相が混在 する （P t +Rh) 相状態を示している。 また、 曲線 Cの両端では、 Rh含有量 が少ない場合に P t相 （4) となり、 Rh含有量が多い場合には Rh相 （5) と なっている。 . FIG. 15 is a phase diagram of a P t—R h alloy which is an electrode material according to the present invention. Ordinate Temperature (° C), the horizontal axis represents the amount of Rh with respect to P t (wt. / 0), curve A solid phase line, curve B the liquidus, the curve C shows the solubility line Yes. This state diagram is based on the data described in THE PGM DATABASE "http://www.platinunimetalsreview.com/jnipgm/index.js non-patent document 2). t And Rh are in a homogeneous melt state, and between curve A and curve B, the liquid and solid phases are mixed. The state on the low temperature side. (2) indicates the complete solid solution state, and the solid solubility limit. The state on the low temperature side from curve C (3) indicates that Rh is solid solution and Z or crystallization with Pt as the main component. This shows a (P t + Rh) phase state in which the Pt phase and Rh phase in which Pt is a solid solution and / or crystallized are mixed. At both ends of curve C, when the Rh content is low, it becomes the Pt phase (4), and when the Rh content is high, it becomes the Rh phase (5). .
図 1 5に示すように、 液相線及び固相線は、 全含有量に亘つて P t金属のバル ク融点 （1 773. 5°C) と Rh金属のバルク融点 （1 963°C) の範囲内にあ る。 2成分系合金の融点が完全に 2つの金属結晶の融点の範囲内にあることは、 一般的なことではなく、 2成分系合金では、 配合比が所定範囲にある場合、 融点 が 2つの金属結晶の融点より降下する場合が多い。 例えば、 A u— N i合金、 T i一 Z r合金、 C r— Mo合金、 Pb— Sn合金、 A g— S r合金などが挙げら れる。 本発明に係る P t— Rh合金では、 Rh含有量が 5重量％の場合に融点が 約 1820°C、 10重量。/。では約 1850°C、 20重量％では約 1 900°C〜 1 903°C、 30重量％では約 1930°C〜 1 933°C、 40重量％では約 195 3°Cとなり、 P t金属のバルク融点より降下することなく、 Rh含有量の増大に 従って合金の融点も上昇し、 R h金属の融点に近づいていく。  As shown in Fig. 15, the liquidus and solidus lines show the bulk melting point of Pt metal (1 773.5 ° C) and the bulk melting point of Rh metal (1 963 ° C) over the entire content. It is in the range. It is not common for the melting point of a binary alloy to be completely within the range of the melting points of two metal crystals. In a binary alloy, if the compounding ratio is within a predetermined range, the melting point of two metals It often falls below the melting point of the crystal. For example, Au-Ni alloy, Ti-Zr alloy, Cr-Mo alloy, Pb-Sn alloy, Ag-Sr alloy and the like can be mentioned. In the Pt—Rh alloy according to the present invention, when the Rh content is 5 wt%, the melting point is about 1820 ° C. and 10 wt. /. Is about 1850 ° C, 20% by weight is about 1900 ° C to 1903 ° C, 30% by weight is about 1930 ° C to 1 933 ° C, and 40% by weight is about 195 3 ° C. Without dropping below the bulk melting point, the melting point of the alloy rises as the Rh content increases and approaches the melting point of the Rh metal.
図 16には、 本発明に係る P t · Rh系金属と他の金属及び合金の融点を記載 した表図を示す。 前述のように、 損耗材粒子発生の要因の 1つとして火花損耗が あり、 この火花損耗はプラズマ生成時における前記放電表面での爆発現象により 引起される。 この火花損耗は高融点の電極材料 （W、 Moなど：図 16参照） を 用いた場合に引起され易い傾向にあることから、 比較的融点が低く、 プラズマ生 成時に電極先端が適度に軟ィ匕されることが好ましいと判断される。 本発明に係る P t-Rh合金の場合、 優れた耐酸化性を有すると共に、 R hの含有量を選択し て融点を適当な範囲に設定することができる。 前記電極材料が P t金属の融点 （ 1773. 5°C) から Rh金属の融点 （ 1 960〜 1966 °C) の範囲内にある 場合、 火花損耗が抑制され、 前記電極材料の機械的強度を考慮した場合、 1 77 3°C〜1953 °Cの範囲に設定されることがより好ましく、 1850°C〜193 3°Cの範囲にある場合に最適.となり得ることが実験から明らかとなつている。 FIG. 16 is a table showing the melting points of the Pt · Rh metal and other metals and alloys according to the present invention. As described above, spark wear is one of the causes of the generation of wear material particles, and this spark wear is caused by an explosion phenomenon on the discharge surface during plasma generation. This spark wear tends to be caused when a high melting point electrode material (W, Mo, etc .: see Fig. 16) is used, so the melting point is relatively low and the electrode tip is soft when plasma is generated. It is considered preferable to be deceived. The Pt—Rh alloy according to the present invention has excellent oxidation resistance, and the melting point can be set within an appropriate range by selecting the Rh content. When the electrode material is in the range of the melting point of Pt metal (1773. 5 ° C) to the melting point of Rh metal (1960-1966 ° C), spark wear is suppressed, and the mechanical strength of the electrode material is reduced. 1 77 when considered It is more preferable that the temperature is set in the range of 3 ° C to 1953 ° C, and it is optimal from the range of 1850 ° C to 1933 ° C.
P t—W合金の融点は、 1870°Cであり、 上述した好適な融点 1 768°C〜 1963°Cの範囲内にある。 し力 しながら、 図 7に示したように、 1:ー^合金 の電極材料を用いたプラズマ生成用電極では、 損耗や融解によって顕著な電極の 変形が観察されている。 P t—W合金の耐酸ィ匕性が低いことに起因していると考 えられ、 P t—W合金は、 プラズマ生成用電極の電極材料 して用いることは不 適当であることを示している。  The melting point of the P t—W alloy is 1870 ° C., which is within the range of the preferable melting point 1 768 ° C. to 1963 ° C. described above. However, as shown in Fig. 7, in the electrode for plasma generation using an electrode material of 1:-^ alloy, remarkable electrode deformation was observed due to wear and melting. This is considered to be due to the low acid resistance of the P t—W alloy, indicating that the P t—W alloy is inappropriate for use as an electrode material for plasma generating electrodes. Yes.
図 1 5では、 P t · Rh系金属の融点が Rhの重量比率に応じて一義的に決定 されるように記載されていた。 しかしながら、 実際には、 Rhの重量比率に対し て常に同一の融点が測定されるものではなく、 合金の作製条件や不純物量等によ りある程度の分布を有している。 本発明者等は、 実測した P t * Rh系金属の融 点に基づき、 上記した融点の分布を反映し、 Rhの重量比率 は重量％) 力 ら融 点 T (°C) を簡易に導出できる近似的な線形関数を求めている。 図 1 7は、 本発 明に係る P t · R h系金属の融点を R hの重量比率 （X重量％) に対してプロッ トしたグラフ図である。 更に、 プロットしたデータに対し、 線形関数をフイツテ イダして前記 T— X関係式を導出し、 分布範囲の大きさを考慮した上限値 （一点 鎖線） と下限値 （二店鎖線） を記載している。 これらのデータから近似的に導出 した T— X関係式は、 次のように表される。  In FIG. 15, the melting point of the Pt · Rh metal is described so as to be uniquely determined according to the weight ratio of Rh. However, in practice, the same melting point is not always measured with respect to the weight ratio of Rh, and has a certain distribution depending on the preparation conditions of the alloy and the amount of impurities. Based on the measured melting point of Pt * Rh metal, the inventors reflect the above melting point distribution, and the melting point T (° C) is easily derived from the Rh weight ratio. An approximate linear function that can be obtained is obtained. Fig. 17 is a graph plotting the melting point of the P t · R h group metal according to the present invention against the weight ratio of R h (X wt%). In addition, a linear function is fitted to the plotted data to derive the T—X relational expression, and an upper limit value (one-dot chain line) and a lower limit value (double store chain line) taking into account the size of the distribution range are described. ing. The T–X relational expression approximately derived from these data is expressed as follows.
T =— 1. 4890X+ 1836. 3±70  T = — 1. 4890X + 1836. 3 ± 70
この第 1の Τ— Χ関係式を用いれば、 Rhの重量比率を調整して P t ' Rh系金 属の融点 T (°C) を所定の温度範囲に設定することができる。 By using this first Τ-Χ relational expression, the melting point T (° C) of the P t 'Rh metal can be set within a predetermined temperature range by adjusting the weight ratio of Rh.
また、 図 1 5に示したに、 本発明に係る P t · Rh系金属は、 Rhの重量比率 の重量比率に対して線形では無く、 0重量％〜 30重量％程度までは、 R hの重 量比率に対して比較的大きな傾きで融点温度が上昇する。 従って、 図 18では、 R hの重量比率が 0重量％〜 30重量％までのデータに線形関数をフイツティン グすることにより、 第 2の T— X関係式を近似的に導出している。 図に示すよう に、 Rhが 0重量％〜30重量。 /0までの範囲では、 線形関数と良い一致を示して おり、 上限値 （一点鎖線） と下限値 （二点鎖線） を考慮すれば、 第 2の T一 X関 係式は、 次の式で表される。 . In addition, as shown in FIG. 15, the Pt · Rh-based metal according to the present invention is not linear with respect to the weight ratio of the Rh weight ratio. The melting point temperature rises with a relatively large slope with respect to the weight ratio. Accordingly, in FIG. 18, the second T−X relational expression is approximately derived by fitting a linear function to data in which the weight ratio of R h is 0 wt% to 30 wt%. As shown in the figure, Rh is 0 wt% to 30 wt%. In the range up to / 0, it shows good agreement with the linear function Taking into account the upper limit (one-dot chain line) and the lower limit (two-dot chain line), the second T-X relation is expressed by the following equation. .
T = - 5. 255 Χ+ 1785. 3± 15  T =-5. 255 Χ + 1785. 3 ± 15
この第 2の Τ— Χ関係式を用いれば、 0≤Χ≤ 30の範囲において、 前記 Rhの 重量比率を調整し、 前記融点 T (°C) をより確実に所定の温度範囲内に設定する ことができる。 Using this second Τ-Χ relational expression, the weight ratio of Rh is adjusted in the range of 0≤Χ≤30, and the melting point T (° C) is more reliably set within the predetermined temperature range. be able to.
図 19は、 本発明に係る P t · Rh系金属の密度 pを Rhの重量比率 （X重量 %) に対してプロットしたグラフ図である。 Rhの重量比率が異なる P t · Rh 系金属の密度 pを実測してプロットしたものであり、 線形関数を用いて密度 p ( g cm3) の前記 X重量％に対する傾向を近似的に導出している。 本発明に係 る P t · Rh系金属をプラズマ生成用電極に用いる場合、 密度 pが 21. 45 g / c m3より大きくなると、 電極の電気的特性を所定値に設定することが困難と なる傾向にあることが分かっている。 これは、 密度の増加と伴に不純物の含有量 が増大し易くなることに起因するものと考えられる。 また、 密度 pが 1 2. 41 g Z c m 3より小さくなると、 電極形成時及び. 又はブラズマ生成時において、 放電表面がポーラス化する傾向にあり、 損耗粒子の発生を増大させる要因の 1つ となる可能性がある。 従って、 前記 P t · Rh系金属の密度 pを 1 2. 41 g.Z cm3〜2'l. 45 gZ cm3の範囲に設定することが好ましく、 プラズマ生成 用電極に安定して所定の電気的特性を付与できると共に、 プラズマ中に不純物や 損耗粒子が混入することを低減化することが可能である。 FIG. 19 is a graph plotting the density p of the P t · Rh metal according to the present invention against the weight ratio of Rh (X wt%). This is a plot of measured density p of P t · Rh metals with different weight ratios of Rh. By using a linear function, the trend of density p (g cm 3 ) with respect to X weight% was derived approximately. ing. When the Pt · Rh metal according to the present invention is used for an electrode for plasma generation, it becomes difficult to set the electrical characteristics of the electrode to a predetermined value when the density p is greater than 21.45 g / cm 3. I know it is in a trend. This is thought to be due to the fact that the impurity content tends to increase with increasing density. Further, the density p is less than 1 2. 41 g Z c m 3 , in and. Or Burazuma when generating electrode formation, the discharge surface tend to pore formation, one of the factors that increases the occurrence of wear particles There is a possibility. Therefore, it is preferable to set the density p of the Pt · Rh-based metal in the range of 12.41 gZ cm 3 to 2'l. 45 gZ cm 3 . In addition to providing properties, it is possible to reduce the contamination of impurities and wear particles in the plasma.
上述したように、 図 1 9では、 前記 p— X関係式が実測値に対するフィッティ ングから導出しており、 測定誤差から見積もられた図中の上限値 （一点鎖線） 及 び下限値 （二点鎖線） に基づき、 次に式で表される。 ■  As described above, in FIG. 19, the p−X relational expression is derived from the fitting to the actual measurement value, and the upper limit value (dashed line) and the lower limit value (2 Based on the dotted line), ■
p =- 0. 08401 X+ 20. 87±0. 6  p =-0. 08401 X + 20. 87 ± 0.6
この p— X関係式によれば、 前記 R hの重量比率を調整して前記密度 pを所定の 密度範囲内に設定することができる。 即ち、 前述の好適な密度範囲 （1 2. 41 g/cm3〜21. 45 g/cm3) 内に本発明に係る P t ' Rh系金属の密度 を容易に設定することができる。 図 20は、 本発明に係る P t · Rh系金属のビッカース硬度 HVを Rhの重量 比率 （ 重量％) に対してプロットしたグラフ図である。 Rhの重量比率が異な る P t · Rh系金属のビッカース硬度 HVを実測してプロットしたものである。 前記 重量％が 0〜30重量％の範囲においては、 ほぼ線形にビッカース硬度 H Vが増加しており、 線形関数を用いてピツカ一ス硬度 HV (Hv) の X重量。 /0に 対する傾向を近似的に導出している。 P t · Rh系金属をプラズマ生成用電極に 用いる場合、 前記ビッカース硬度 HVが 13 OHvを越えると放電表面が脆くな り、 所定形状にプラズマ生成用電極を加工することが困難となると共に、 前記損 耗粒子の発生が増大する。 また、 ビッカース硬度 HVが 5 OHvより小さくなる と耐久性が明確な低下を示す。 即ち、 プラズマ生成用電極の電極性能に基づき、 P t · Rh系金属は、 電極材料として、 ビッカース硬度 HVが 5 OHv〜； I 30 Hvの範囲に設定されることが好ましい。 According to this p—X relational expression, the density p can be set within a predetermined density range by adjusting the weight ratio of R h. That is, the density of the Pt′Rh metal according to the present invention can be easily set within the above-described preferred density range (12.41 g / cm 3 to 21.45 g / cm 3 ). FIG. 20 is a graph plotting the Vickers hardness HV of the Pt · Rh-based metal according to the present invention against the weight ratio (% by weight) of Rh. This is a plot of measured Vickers hardness HV of P t · Rh metals with different Rh weight ratios. In the range of 0% to 30% by weight, the Vickers hardness HV increases almost linearly, and the X weight of the Pickers hardness HV (Hv) using a linear function. The trend for / 0 is approximately derived. When a Pt · Rh-based metal is used for a plasma generating electrode, if the Vickers hardness HV exceeds 13 OHv, the discharge surface becomes brittle, and it becomes difficult to process the plasma generating electrode into a predetermined shape. The generation of wear particles increases. In addition, when the Vickers hardness HV is less than 5 OHv, the durability is clearly reduced. That is, based on the electrode performance of the plasma generating electrode, the Pt · Rh-based metal is preferably set as an electrode material in a range of Vickers hardness HV from 5 OHv to I 30 Hv.
前述のように、 図 20では、 前記ビッカース硬度 HV (Hv) と前記 重量％ の HV— X関係式が導出されており、 ビッカース硬度 HVの上限値 （一点鎖線） 及び下限値 （二点鎖線） に基づき、 次に式で表される。  As described above, in FIG. 20, the Vickers hardness HV (Hv) and the weight% HV—X relational expression are derived. Based on
HV =— 2. 76X+ 51. 85±1 5  HV = — 2. 76X + 51. 85 ± 1 5
この H V— X関係式により前記ピツカ一ス硬度 H Vを所定範囲内に設定すること ができ、 前記電極材料に好適な加工性が付与されると共に、 プラズマ生成時にお ける損耗粒子の発生を抑制することができる。 By this HV-X relational expression, the picker hardness HV can be set within a predetermined range, and suitable workability is imparted to the electrode material, and generation of wear particles during plasma generation is suppressed. be able to.
図 21は、 本発明に係る管状の棒状電極 （以下 「管状電極 44」 と呼ぶ） を有 するペンジェット型プラズマ処理装置の構成概略図である。 以下、 同一の部材に 関しては、 符号及びその説明を一部省略する。 このペンジェット型プラズマ処理 装置は、 前記管状電極 44にガス導入口 50が設けられ、 作動ガス 28が前記ガ ス導入口 50から前記管状電極 44内を流通して、 ブラズマ発生部 4 aに供給さ れる。 管状電極先端部 46の電極先端面 46 aとノズル状電極 16の間に高電圧 パルスを印加してアーク放電を生起し、 プラズマを生成する。 更に、 この実施例 では、 第 2ガス導入口 56が設けられ、 前記作動ガス 28と同一のガス又は目的 に応じて種々の物質を作動ガスとして供給することができる。 本発明に係るブラ ズマ生成用電極は、 前記管状電極 44の電極先端面 46 a及び 又はその近傍の 放電表面が P t · Rh系金属から形成され、 電極損耗及び損耗材料粒子の発生が 抑制される。 FIG. 21 is a schematic configuration diagram of a pen jet type plasma processing apparatus having a tubular rod electrode (hereinafter referred to as “tubular electrode 44”) according to the present invention. In the following, the same reference numerals and descriptions thereof are partially omitted for the same members. In this pen jet type plasma processing apparatus, the tubular electrode 44 is provided with a gas introduction port 50, and the working gas 28 circulates through the tubular electrode 44 from the gas introduction port 50 and is supplied to the plasma generator 4a. It is done. A high voltage pulse is applied between the electrode tip surface 46a of the tubular electrode tip 46 and the nozzle-like electrode 16 to generate arc discharge and generate plasma. Further, in this embodiment, the second gas inlet 56 is provided, and various substances can be supplied as the working gas in accordance with the same gas or purpose as the working gas 28. The electrode for plasma generation according to the present invention includes an electrode tip surface 46a of the tubular electrode 44 and the vicinity thereof. The discharge surface is made of Pt · Rh-based metal, and electrode wear and wear material particles are suppressed.
図 22は、 本発明に係るプラズマ生成用電極がグラインデイングアーク型電極 60である場合のプラズマ発生部 4 aの構成概略図である。 前記グラインディン グアーク型電極では、 流通する作動ガス 28中に配置した末広がり状 （下流側に 広がる） の電極 60 a、 60 bが電流線 62 a、 62 bに接続され、 電極間に高 電圧パルスを印加してアーク放電を生起することによりプラズマ Pが発生する。 アーク放電の電流路 61を形成している強電離プラズマ （陽光柱 （ 「コラム」 と も言う） 、 あるいはストリーマ） と、 電流がほとんど流れない弱電離プラズマ 6 5 (プラズマプルーム） とが混在して発生する。 前記電極 60 a、 6 O bの放電 表面 63 a、 63 bが P t · Rh系金属から形成されることにより、 グラインデ ィングアーク型電極 60の電極損耗を抑制し、 損耗材料粒子の発生を低減化する ことができる。  FIG. 22 is a schematic configuration diagram of the plasma generating unit 4 a when the plasma generating electrode according to the present invention is a grinding arc type electrode 60. In the grinding arc type electrode, the end-spread electrodes 60 a and 60 b arranged in the circulating working gas 28 are connected to the current lines 62 a and 62 b, and a high voltage pulse is applied between the electrodes. Plasma P is generated by applying arc to cause arc discharge. A mixture of strongly ionized plasma (also known as “column”) or streamer that forms the current path 61 of arc discharge and weakly ionized plasma 65 5 (plasma plume) that hardly flows current. appear. The discharge surfaces 63a and 63b of the electrodes 60a and 6Ob are made of Pt · Rh-based metal to suppress electrode wear of the grinding arc electrode 60 and reduce the generation of wear material particles. It can be
本発明に係るプラズマ処理装置がグラインディングアーク型電極 60を有する 場合、 P t - Rh系金属からなる電極 60 a、 60 bの断面直径が約 1. 6 mm (断面積：約 2 mm2) であり、 前記パルス周波数が約 30 k H z、 前記パルス 幅が約 3 n s、 供給される作動ガスの流量が約 40 L, 'm i nである場合、 前記 供給電力が以下の値に設定されるとき、 大気や種々の作動ガスに好適なアーク放 電を生起して、 プラズマを連続的又は間欠的に生成することができる。 この場合 、 平均電力が 300W (15 OW mm2) 以下、 最大印加電圧が約 7 k V、 最 大ピーク電流が 3A (1. 5A. mm2) 以下に設定されることが好ましい。 こ こで、 単位面積は、 電極 60 a、 60 bの単位断面積としている。 前記グライン ディングアーク型電極 60の場合、 放電表面 63 a、 63 bの間にアーク放電が 発生するから、 放電面積が大きく、 前記供給電力を比較的大きな値に設定するこ とができ、 比較的多量の作動ガスを流通させてプラズマ化することができる。 従 つて、 前記平均電力の密度を 15 OWZ'mm2以下に設定すれば、 前記断面積に 応じてブラズマの生成量を適宜に調整することができる。 When the plasma processing apparatus according to the present invention has the grinding arc type electrode 60, the cross-sectional diameters of the electrodes 60a and 60b made of Pt-Rh metal are about 1.6 mm (cross-sectional area: about 2 mm 2 ). When the pulse frequency is about 30 kHz, the pulse width is about 3 ns, and the flow rate of the supplied working gas is about 40 L, 'min, the supply power is set to the following value: Sometimes it is possible to generate arc discharge suitable for the atmosphere and various working gases to generate plasma continuously or intermittently. In this case, the average power is 300W (15 OW mm 2) or less, the maximum applied voltage is about 7 k V, the maximum peak current 3A (1. 5A. Mm 2) is preferably set to below. Here, the unit area is the unit cross-sectional area of the electrodes 60a and 60b. In the case of the grinding arc type electrode 60, arc discharge is generated between the discharge surfaces 63a and 63b. Therefore, the discharge area is large, and the supplied power can be set to a relatively large value. A large amount of working gas can be circulated to generate plasma. Therefore, if the density of the average power is set to 15 OWZ'mm 2 or less, the amount of plasma generated can be appropriately adjusted according to the cross-sectional area.
図 23は、 本発明に係るブラズマ発生用電極 Ί 0が鋸刃状電極 72 a、 72 b を具備する場合の構成概略図である。 このプラズマ発生用電極 70には、 両外側 の鋸刃状電極 7 2 a、 7 2 b及びアース型電極 7 4から構成され、 これらの電極 には、 電源 7 6 a、 7 6 bが接続されている。 前記鋸刃状電極 7 2 a、 7 2 bに は、 各々、 先鋭な突起 7 7 a、 7 7 bが複数設けられ、 この先鋭な突起 7 7 a、 7 7 bに電界を集中させることにより、 アーク放電が容易に生起され、 プラズマ Pが生成される。 前記鋸刃状電極 7 2 a、 7 2 bの放電表面が P t · R h系金属 から形成されることによって、 突起 7 7 a、 7 7 bへの電界集中による電極損耗 を抑制し、 損耗材料粒子の発生を低減化することができる。. FIG. 23 is a schematic configuration diagram in the case where the plasma generating electrode 0 according to the present invention includes saw-toothed electrodes 72 a and 72 b. This plasma generating electrode 70 has both outer sides The sawtooth electrodes 7 2 a and 7 2 b and the earth-type electrode 74 are connected to the power sources 76 6 a and 76 b. Each of the sawtooth electrodes 7 2 a and 7 2 b is provided with a plurality of sharp projections 7 7 a and 7 7 b, and by concentrating the electric field on these sharp projections 7 7 a and 7 7 b Arc discharge easily occurs and plasma P is generated. By forming the discharge surface of the sawtooth electrodes 7 2 a and 7 2 b from Pt · Rh-based metal, electrode wear due to electric field concentration on the protrusions 7 7 a and 7 7 b can be suppressed. Generation of material particles can be reduced. .
本発明は、 上記実施形態や変形例に限定されるものではなく、 本発明の技術的 思想を逸脱しない範囲における種々変形例、 設計変更などをその技術的範囲内に 包含するものであることは云うまでもない。  The present invention is not limited to the above-described embodiments and modifications, and includes various modifications and design changes within the technical scope without departing from the technical idea of the present invention. Needless to say.
(産業上の利用可能性） (Industrial applicability)
本発明に係るプラズマ生成用電極は、 少なくとも前記放電表面が P t · R h系 金属から形成されるから、 優れた耐酸化性を有し、 好適な融点を有するから、 種 々の放電によるプラズマ生成時の電極損耗及び損耗材料粒子の放出を極めて微量 に抑制することができる。 従って、 プラズマ生成用電極を用いて高純度なプラズ マを発生させるプラズマ生成装置を提供することができる。 更に、 プラズマ生成 装置による不純物の付着を抑制し、 均一な被処理物表面のプラズマ処理を実現す ることができる。 例えば、 本発明に係るプラズマ生成装置により生成されたァー クプラズマは、 各種の加工や表面処理等に用いられ、 大気圧程度の圧力下におい て生成可能なプラズマであり、 種々の原料ガス （以下 「作動ガス」 と呼ぶ） から 容易にプラズマを生成することができる。 半導体製品、 金属製品、 ガラス製品、 加工用部材等の被処理物表面をプラズマ処理することにより、 原料ガスや供給電 力に応じて表面加工 （エッチング、 表面コーティングなど） 、 表面改質 （濡れ性 改善、 接着性改善、 生体融和性改善） 、 洗浄及びデスミア処理等を行うことがで さる。  The plasma generating electrode according to the present invention has excellent oxidation resistance and has a suitable melting point because at least the discharge surface is formed of a Pt · Rh-based metal, so that plasma generated by various discharges Electrode wear and generation of wear material particles during generation can be suppressed to a very small amount. Therefore, it is possible to provide a plasma generation apparatus that generates a high-purity plasma using the plasma generation electrode. Furthermore, it is possible to suppress the adhesion of impurities by the plasma generation apparatus and realize a uniform plasma treatment of the surface of the workpiece. For example, the arc plasma generated by the plasma generation apparatus according to the present invention is a plasma that can be generated under a pressure of about atmospheric pressure, and is used for various processes and surface treatments. It is easy to generate plasma from "working gas". Surface processing (etching, surface coating, etc.) and surface modification (wetting properties) according to the raw material gas and power supply by plasma processing the surface of workpieces such as semiconductor products, metal products, glass products, and processing members Improvement, adhesion improvement, biocompatibility improvement), cleaning and desmear treatment.

Claims

1. 放電によって供給ガスのプラズマを発生させるプラズマ生成装置のプラズマ 生成用電極であって、 このプラズマ生成用電極の少なくとも放電表面が P t !_γ R hY (0≤Y< 1 ) で表される P t · R h系金属の電極材料から形成されるこ とを特徴とするブラズマ生成用電極。 1. A plasma generation electrode of a plasma generation apparatus that generates plasma of a supply gas by discharge, and at least the discharge surface of this plasma generation electrode is represented by P t! _ Γ R h Y (0≤Y <1) An electrode for plasma generation, characterized in that it is formed from a Pt · Rh-based metal electrode material.
2. 前記 P t · R h系金属の格一一卩青子定数 aが 3. 8 θΑ〜3·. 92 Αの範囲にある 請求項 1に記載のプラズマ生成用電極。  2. The electrode for generating plasma according to claim 1, wherein the Pt · Rh-based metal has a first-order and blue-green constant a in a range of 3.8 θΑ to 3.92Α.
3. 前記 P t · R h系金属の融点が 1 7の 7 3°C〜 1 9 6 6 °Cの範囲にある請求項 1又は 2に記載のプラズマ生成用電極。  3. The electrode for generating plasma according to claim 1 or 2, wherein the melting point of the Pt · Rh-based metal is in the range of 73 ° C to 1966 ° C of 1-7.
4. 前記 P t · R h系金属の結晶構造が面心立方囲格子 （FCC) 構造である請求 項 1〜 3のいずれかに記載のプラズマ生成用電極。  4. The plasma generating electrode according to claim 1, wherein the crystal structure of the P t · R h group metal is a face centered cubic lattice (FCC) structure.
5. 前記 P t · R h系金属の結晶粒径が 0. 5 μ π！〜 1 00 fi mの範囲にある請 求項 1〜 4のいずれかに記載のプラズマ生成用電極。  5. The crystal grain size of the P t · R h group metal is 0.5 μπ! The electrode for plasma generation according to any one of claims 1 to 4, wherein the electrode is in the range of ~ 100 fi m.
6. 前記 P t · R h系金属の密度 pが 1 2. 4 1 g/c m3〜2 1. 45 g ' c m3の範囲にある請求項 1〜 5のいずれかに記載のプラズマ生成用電極。 6. The P t · R h system density p metals 1 2. 4 1 g / cm 3 ~2 1. 45 g ' for generating plasma according to any one of claims 1 to 5 in the range of cm 3 electrode.
7. 前記 P t . R h系金属のビッカース硬度 HVが 5 O Hv〜： 1 3 O Hvの範囲 にある請求項 1〜 6のいずれかに記載のプラズマ生成用電極。  7. The plasma generating electrode according to claim 1, wherein the Pt.Rh-based metal has a Vickers hardness HV in a range of 5 O Hv to 13 O Hv.
8. 前記 P t · Rh系金属に占める R hの重量比率を X重量％とするとき、 前記 P t · Rh系金属の格子定数 a (A) と前記 重量％の a— X関係式が  8. When the weight ratio of Rh in the Pt · Rh metal is X wt%, the lattice constant a (A) of the Pt · Rh metal and the a-X relational expression of the wt% are
a =- 0. 00 1 1 3 X+ 3. 9 0 8 ± 0. 0 2  a =-0. 00 1 1 3 X + 3. 9 0 8 ± 0. 0 2
で表され、 前記 R hの重量比率を調整して前記格子定数 aが設定される請求項 1 〜 7に記載のブラズマ生成用電極。 The plasma generating electrode according to claim 1, wherein the lattice constant a is set by adjusting a weight ratio of the R h.
9. 前記 P t · Rh系金属に占める R hの重量比率を 重量％とするとき、 前記 P t · R h系金属の融点 T (°C) と前記 X重量％の T一 X関係式が  9. When the weight ratio of Rh to the Pt · Rh metal is wt%, the melting point T (° C) of the Pt · Rh metal and X
T =- 1. 4 8 9 0 X+ 1 8 3 6. 3 ± 7 0  T =-1. 4 8 9 0 X + 1 8 3 6. 3 ± 7 0
で表される又は前記 重量％が 0≤ X≤ 3 0の範囲にあるとき Τ— X関係式がOr when the weight percentage is in the range 0≤ X≤ 3 0
Τ = - 5. 2 5 5 Χ+ 1 7 8 5. 3 ± 1 5 Τ =-5. 2 5 5 Χ + 1 7 8 5. 3 ± 1 5
で表され、 前記 R hの重量比率を調整して前記融点 Tが設定される請求項 1〜 8 のいずれかに記載のプラズマ生成用電極。 The melting point T is set by adjusting the weight ratio of the Rh. The plasma generating electrode according to any one of the above.
10. 前記 P t · Rh系金属に占める Rhの重量比率が 重量％であるとき、 前 記 P t · Rh系金属の密度 p (g/cm3) と前記 重量％の関係式が 10. When the weight ratio of Rh to the Pt · Rh metal is% by weight, the relationship between the density p (g / cm 3 ) of the Pt · Rh metal and the wt% is
=- 0. 08401 X+ 20. 87±0. 6  =-0. 08401 X + 20. 87 ± 0.6
で表され、 前記 Rhの重量比率を調整して前記密度 Pが設定される請求項 1~9 のいずれかに記載のプラズマ生成用電極。 10. The plasma generating electrode according to claim 1, wherein the density P is set by adjusting a weight ratio of the Rh.
1 1. 前記 P t · Rh系金属に占める Rhの重量比率が 重量％であるとき、 前 記 P t · Rh系金属のビッカース硬度 HV (Hv) と前記 重量％の関係式が 1 1. When the weight ratio of Rh to the Pt · Rh metal is% by weight, the relational expression of Vickers hardness HV (Hv) of the Pt · Rh metal and the wt% is
HV = - 2. 76 X+ 51. 85 ±15 HV =-2. 76 X + 51. 85 ± 15
で表され、 前記 Rhの重量比率を調整して前記ビッカース硬度 HVが設定される 請求項 1〜 10のいずれかに記載のプラズマ生成用電極。 The electrode for plasma generation according to any one of claims 1 to 10, wherein the Vickers hardness HV is set by adjusting a weight ratio of the Rh.
1 2. 前記 P t · 1 11系金属に占める1 の重量比率が0重量％〜40重量％の 範囲に設定される請求項 1〜 11のいずれかに記載のプラズマ生成用電極。 1. The electrode for generating plasma according to claim 1, wherein a weight ratio of 1 in the P t · 111 series metal is set in a range of 0 wt% to 40 wt%.
1 3. 前記放電が生起される電極が高電界電極と低電界電極を対向させて構成さ れ、 前記高電界電極の前記対向面に前記放電表面を配置し、 少なくとも前記高電 界電極の放電表面が前記電極材料から形成される請求項 1〜 12のいずれかに記 載のプラズマ生成用電極。 1 3. The electrode in which the discharge is generated is configured such that a high field electrode and a low field electrode are opposed to each other, the discharge surface is disposed on the facing surface of the high field electrode, and at least the discharge of the high field electrode The electrode for plasma generation according to any one of claims 1 to 12, wherein a surface is formed of the electrode material.
14. 前記高電界電極が棒状電極であり、 前記低電界電極がブラズマ射出口を有 するノズル状電極であり、 前記電極がペンジエツト型電極を構成する請求項 13 に記載のブラズマ生成用電極。  14. The plasma generating electrode according to claim 13, wherein the high electric field electrode is a rod-shaped electrode, the low electric field electrode is a nozzle-shaped electrode having a plasma injection port, and the electrode constitutes a pendant electrode.
15. 前記棒状電極の少なくとも先端部が前記電極材料から形成される請求項 1 4に記載のブラズマ生成用電極。  15. The plasma generating electrode according to claim 14, wherein at least a tip portion of the rod-shaped electrode is formed of the electrode material.
16. 前記高電界電極が放電表面側に 1つ以上の突起を有する突起型電極である 請求項 13に記載のブラズマ生成用電極。  16. The plasma generating electrode according to claim 13, wherein the high electric field electrode is a protruding electrode having one or more protrusions on the discharge surface side.
1 7. 請求項 1〜16のいずれかに記載のプラズマ生成用電極を用いてプラズマ を生成することを特徴とするプラズマ生成装置。 1 7. A plasma generating apparatus that generates plasma using the plasma generating electrode according to any one of claims 1 to 16.
18. 請求項 1 7に記載のブラズマ生成装置により被処理物表面をブラズマ処理 することを特徴とするプラズマ処理装置。 ·  18. A plasma processing apparatus for performing plasma processing on a surface of an object to be processed by the plasma generating apparatus according to claim 17. ·
PCT/JP2007/052803 2007-02-09 2007-02-09 Pt rh based plasma generation electrode, plasma generation apparatus and plasma processing system WO2008096454A1 (en)

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