WO2021107049A1 - Ionizing electrode and sapphire member - Google Patents

Ionizing electrode and sapphire member Download PDF

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Publication number
WO2021107049A1
WO2021107049A1 PCT/JP2020/044103 JP2020044103W WO2021107049A1 WO 2021107049 A1 WO2021107049 A1 WO 2021107049A1 JP 2020044103 W JP2020044103 W JP 2020044103W WO 2021107049 A1 WO2021107049 A1 WO 2021107049A1
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Prior art keywords
tube
sapphire
electrode
peripheral surface
axial direction
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PCT/JP2020/044103
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French (fr)
Japanese (ja)
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善則 久保
一郎 坂野
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京セラ株式会社
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    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/16—Oxides
    • C30B29/20—Aluminium oxides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/02—Constructional details
    • H01S3/03—Constructional details of gas laser discharge tubes
    • H01S3/038—Electrodes, e.g. special shape, configuration or composition
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/09—Processes or apparatus for excitation, e.g. pumping
    • H01S3/097—Processes or apparatus for excitation, e.g. pumping by gas discharge of a gas laser
    • H01S3/0977—Processes or apparatus for excitation, e.g. pumping by gas discharge of a gas laser having auxiliary ionisation means
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/14—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range characterised by the material used as the active medium
    • H01S3/22—Gases
    • H01S3/223—Gases the active gas being polyatomic, i.e. containing two or more atoms
    • H01S3/225—Gases the active gas being polyatomic, i.e. containing two or more atoms comprising an excimer or exciplex

Definitions

  • the present disclosure relates to an ionization electrode and a sapphire member used in an excimer laser device or the like.
  • An excimer laser is a laser that uses an excimer.
  • a mixed gas containing a halogen gas and a rare gas is sealed and discharged, an excited rare gas / halogen dimer (excimer) is generated, and energy is generated when the gas is transferred to the base state rare gas and halogen. Is converted into light and emitted.
  • a continuous laser can be obtained by continuously repeating the discharge.
  • the laser wavelength obtained varies depending on the combination of the enclosed gas, and ArF excimer laser (wavelength 193 nm), KrF excimer laser (wavelength 248 nm), XeCl excimer laser (wavelength 308 nm), XeF excimer laser (wavelength 351 nm), etc.
  • ArF excimer laser wavelength 193 nm
  • KrF excimer laser wavelength 248 nm
  • XeCl excimer laser wavelength 308 nm
  • XeF excimer laser wavelength 351 nm
  • preliminary ionization is performed in order to obtain a stable laser excitation discharge. This is because the laser gas is ionized in advance.
  • a first electrode and a second electrode are arranged inside and outside the tube which is an insulator, respectively, and a voltage is applied between these electrodes to generate a corona discharge.
  • Patent Document 1 describes the use of polycrystalline or single crystal alumina as the tube.
  • the tube used for such a preliminary ionization electrode is required to have good corrosion resistance and discharge characteristics because it is discharged in an atmosphere of a corrosive gas such as a halogen gas. Further, in order to insert the first electrode and to cause an appropriate corona discharge as a preliminary ionization, the tube is required to have little deformation and excellent mechanical strength.
  • the first ionization electrode of the present disclosure is used in a device using a corrosive gas, and is a tube made of sapphire, a first electrode inserted inside the tube, and the outside of the tube.
  • the tube is provided with a second electrode arranged in the tube, and the axial direction of the tube is substantially parallel to the c-axis direction of the sapphire.
  • the second ionizing electrode of the present disclosure is used in a device using a corrosive gas, and is a tube made of sapphire, a first electrode inserted inside the tube, and the outside of the tube.
  • the second electrode is provided with a second electrode arranged in, and the axial direction of the tube is substantially perpendicular to the c-axis direction of the sapphire, and the second electrode is substantially parallel to the c-axis of the sapphire when viewed from the axial center of the tube. Have been placed.
  • the sapphire member of the present disclosure has a tube shape used in an apparatus using a corrosive gas, has an inner peripheral surface and an outer peripheral surface extending in the axial direction, and is deep from the inner peripheral surface and the outer peripheral surface, respectively. There is no processed alteration layer in the region within 0.5 mm, and there are bubbles arranged in a streak in the axial direction.
  • FIG. 2A It is explanatory drawing which shows the use example of the ionization electrode of this disclosure in an excimer laser apparatus. It is the schematic sectional drawing which shows one Embodiment of the ionization electrode of this disclosure. It is a schematic perspective view of the ionization electrode shown in FIG. 2A. It is a top view which shows an example of the mold used for manufacturing the tube made of sapphire. It is a partial top view of the AA'line of FIG. It is a micrograph which shows an example of the streak bubble which the sapphire member of this disclosure has
  • FIG. 1 is an explanatory view showing an example of use of the ionization electrode of the present disclosure in an excimer laser apparatus
  • FIGS. 2A and 2B are a schematic cross-sectional view and a schematic perspective view showing an embodiment of the ionization electrode shown in FIG. Is.
  • the ionization electrode may be referred to as a preliminary ionization electrode.
  • the excimer laser apparatus includes a chamber 100 in which a mixed gas containing a halogen gas and a rare gas, which are corrosive gases, is sealed.
  • a mixed gas containing a halogen gas and a rare gas, which are corrosive gases is sealed.
  • the halogen gas include fluorine (F 2 ) gas
  • the rare gas include argon (Ar) gas and krypton (Kr) gas.
  • an anode 101 for oscillating a laser beam and a cathode 102 are arranged to face each other as main electrodes.
  • the anode 101 and the cathode 102 each extend long in the vertical direction of the paper surface and are connected to the high voltage pole and the ground pole (neither shown) of the pulse voltage source 103.
  • the ground electrode is connected to, for example, chamber 100.
  • a preliminary ionization electrode 10 is provided in the chamber 100.
  • the preliminary ionization electrode 10 stabilizes the pulse discharge P by causing a discharge called preliminary ionization in which the mixed gas is ionized prior to the pulse discharge P.
  • the preliminary ionization electrode 10 includes a tube 3 made of insulating sapphire (hereinafter, may be referred to as sapphire tube 3) and a first electrode inserted inside the sapphire tube 3. 1 and a second electrode 2 arranged outside the sapphire tube 3 are provided.
  • the first electrode 1 is formed of a round bar-shaped conductor.
  • the second electrode 2 is formed of a plate-shaped conductor.
  • the first electrode 1 is connected to the ground electrode of the pulse voltage source 103.
  • the sapphire tube 3 is arranged parallel to the longitudinal direction of the main electrode.
  • the sapphire tube 3 shown in FIG. 2B has both ends open, but one end may be sealed. Further, the light emission due to the preliminary ionization discharge may be generated on the inner peripheral surface 3a side of the shear tube 3 or on the outer peripheral surface 3b side. Since the sapphire tube 3 is transparent, the light generated on the inner peripheral surface 3a side can be transmitted.
  • Sapphire alumina single crystal
  • various physical properties such as coefficient of thermal expansion, permittivity, and refractive index are different in the direction perpendicular to the c-axis and the direction parallel to the c-axis. .. Therefore, it may be deformed due to expansion and contraction due to a temperature change, the state of the potential may differ depending on the direction in which the voltage is applied, and the speed and refraction may differ depending on the traveling direction of light.
  • the axial direction of the sapphire tube 3, that is, the direction of the arrow B in FIG. 2B is substantially parallel to the c-axis direction of the sapphire.
  • substantially parallel to the c-axis direction means that in addition to being completely parallel, an angle deviation of about ⁇ 10 ° from the parallel direction is allowed.
  • the thickness of the sapphire tube 3 is preferably 0.5 mm or more and 10 mm or less, preferably 1 mm or more and 5 mm or less.
  • the outer diameter of the sapphire tube 3 is preferably 1 mm or more and 50 mm or less, preferably 2 mm or more and 25 mm or less.
  • the total length of the sapphire tube 3 is 500 mm or more, and the straightness of the outer peripheral surface is 1.0 mm or less, preferably 0.5 mm or less. This facilitates the insertion of the first electrode 1 into the sapphire tube 3. Straightness can be measured, for example, by the following method.
  • Two V-shaped blocks conforming to JIS B7540 are arranged on the surface plate, and both ends of the tube 3 are supported by V-planes.
  • the tube 3 is rotated once on the V surface, and the distance from the reference line at the position where the outer peripheral surface 3b is farthest from the reference line connecting both ends is measured using a microgauge or the like to obtain straightness.
  • the surface of the sapphire tube 3 is preferably smooth in terms of corrosion resistance.
  • the surface roughness (arithmetic mean roughness) Sa on the inner and outer peripheral surfaces of the sapphire tube 3 is preferably 1.0 ⁇ m or less, preferably 0.2 ⁇ m or less.
  • the surface roughness Sa can be measured according to ISO25178, for example, using a laser microscope with a measurement area of 500 ⁇ m ⁇ .
  • the sapphire tube 3 can be produced by using the EFG method (edge defined film fed growth method) known as a method for growing a single crystal.
  • EFG method edge defined film fed growth method
  • the raw material of the single crystal filled in the crucible is heated and melted, and the seed crystal is formed in the sapphire melt raised to the upper surface of the mold by utilizing the capillary phenomenon by the slit in the mold installed in the crucible.
  • a single crystal having a predetermined shape is grown by bringing the (seed) into contact with the seed and pulling it upward.
  • FIG. 3 is a schematic view of the mold 4 used for manufacturing the sapphire tube 3 as a top view
  • FIG. 4 is a cross-sectional view taken along the line AA'.
  • the mold 4 includes an annular outer mold 4a on the outer peripheral side and an inner mold 4b arranged inside the annular outer mold 4a.
  • an annular slit 5 exists between the annular outer mold 4a and the inner mold 4b.
  • the lower end of the slit 5 is immersed in the melt existing in the lower part of the mold 4, and has a function of supplying the melt to the opening 6 of the slit 5 by a capillary phenomenon. Therefore, the melt is present in the opening 6.
  • a crystal growing surface 7 is arranged on the upper surface of the mold 4 so as to surround the opening 6, and a recess 9 is formed on the upper surface of the mold 4 at a position corresponding to a through hole of the sapphire tube 3. ing.
  • the crystal growth region 8 is a portion of the upper surface of the mold 4 excluding the recess 9, that is, a region where the opening 6 of the slit 5 and the crystal growth surface 7 are combined.
  • the crystal growth surface 7 is inclined so as to be lower toward the slit 5, but it may be a horizontal surface.
  • the sapphire melt rises through the slit 5, reaches the opening 6, and extends to the crystal growth surface 7. That is, the sapphire melt exists on the crystal growth region 8.
  • the seed crystal can be brought into contact with the sapphire melt, and then the seed crystal can be produced as a sapphire tube 3 that substantially coincides with the crystal growth region 8.
  • the sapphire melt can be obtained by heating and melting a sapphire raw material composed of alumina powder at a temperature equal to or higher than the melting point of alumina, for example, 2080 ° C.
  • the cross-sectional shape of the seed crystal may be substantially the same as that of the crystal growth region 8. Seed crystals can be prepared by processing sapphire lumps.
  • the seed crystal is made of sapphire, and the pulling direction is the c-axis.
  • the obtained sapphire tube 3 has an axial direction substantially parallel to the c-axis of the sapphire.
  • the obtained tubular sapphire member has relatively uniform (isotropic) physical properties in the thickness direction, is less deformed due to thermal expansion, has a relatively uniform dielectric constant, and has a uniform discharge. Therefore, the obtained tubular sapphire member is suitable as the sapphire tube 3 in the excimer laser apparatus. It can be confirmed by measuring the crystal orientation using the X-ray diffraction method that the axial direction of the tube 3 is substantially parallel to the c-axis of sapphire.
  • the sapphire member used as the sapphire tube 3 has an inner peripheral surface 3a and an outer peripheral surface 3b extending in the axial direction, and has a depth of 0. There is no processed alteration layer in the region within 5 mm, and the bubbles are arranged in a streak pattern in the axial direction.
  • a work-altered layer can be defined as a layer in which crystal defects such as microcracks and dislocations are introduced into the crystal surface by mechanical processing such as cutting, grinding, and polishing. Specifically, it is more than a bulk portion. Refers to a surface layer with many microcracks, dislocations, etc. (for example, 10 times or more).
  • the corrosion resistance is lowered and particles are likely to be generated.
  • the processed altered layer exists in a region having a depth of 0.5 mm or less can be confirmed by, for example, optical microscope observation, CL (cathodoluminescence) observation, and TEM (transmission electron microscope) observation.
  • CL cathodoluminescence
  • TEM transmission electron microscope
  • the sapphire member has bubbles arranged in a streak pattern in the axial direction of the tube 3 in regions within 0.5 mm in depth from the inner peripheral surface 3a and the outer peripheral surface 3b, respectively.
  • FIG. 5 shows an example of streaky bubbles generated on the outer peripheral surface of the sapphire tube 3.
  • the streaky bubbles can absorb and mitigate the impact of the mechanical impact, thermal impact, etc. on the sapphire tube 3 and stop the expansion of cracks.
  • the streaky bubbles determine the growing conditions (pulling speed, atmosphere, growing temperature, etc.) when pulling the tube 3 from the surface of the mold 4 and the configuration and shape of the growing device (shape, inclination angle, etc. of the crystal growing surface 7). It can be generated (or the status of occurrence is controlled) by adjusting.
  • the streaky bubbles have a diameter of, for example, about 5 ⁇ m to 40 ⁇ m, and one to several streaky bubbles are arranged in the circumferential direction of the tube 3 and arranged in a streak shape in the axial direction.
  • the width of one muscle is, for example, 300 ⁇ m or less, and a plurality of muscles are arranged in the circumferential direction of the tube 3.
  • the pitch between the muscles is, for example, about 0.3 mm to 2 mm.
  • the density of bubbles per unit area as seen from the outer peripheral surface or the inner peripheral surface is 250 to 2500 cells / mm 2 .
  • the density of bubbles is determined, for example, by measuring the number of bubbles 1b in the region containing the streaky bubbles 1b and dividing by the area of the measurement area.
  • the ionization electrode (second ionization electrode) according to another embodiment of the present disclosure will be described.
  • the difference between the second ionizing electrode and the first ionizing electrode described above is that the c-axis of the sapphire is substantially parallel to the arrow A in FIG. 2A, and the axial direction of the sapphire tube 3, that is, FIG. 2B.
  • the direction of the arrow B is substantially perpendicular to the c-axis direction of the sapphire
  • the second electrode 2 is located in the direction substantially parallel to the c-axis of the sapphire when viewed from the axis of the tube 3, that is, in the direction of the arrow A in FIG. 2A. It is the same as the first ionizing electrode except that it is arranged.
  • being substantially perpendicular to the c-axis direction of sapphire means that in addition to being completely vertical, a deviation of about ⁇ 10 ° from the vertical direction is allowed.
  • the direction substantially parallel to the c-axis of sapphire means that in addition to being completely parallel, a deviation of about ⁇ 10 ° from the parallel direction is allowed.
  • the dielectric constant of sapphire is high in the c-axis direction, electrolysis in a gas containing a corrosive gas becomes strong, and it becomes easy to discharge.
  • the c-axis of the seed crystal is arranged so as to be substantially perpendicular to the pulling direction, and in that state.
  • the sapphire melt may be pulled up. It can be confirmed by the crystal orientation measurement using the X-ray diffraction method that the axial direction of the sapphire tube 3 is substantially perpendicular to the c-axis of the sapphire.
  • the sapphire member used in the second ionization electrode according to the present embodiment also has no processing alteration layer in the regions within 0.5 mm in depth from the inner peripheral surface 3a and the outer peripheral surface 3b, respectively, and is in the axial direction. It has bubbles arranged in a streak pattern.
  • the first and second ionization electrodes of the present disclosure both include a tube made of sapphire, there is little deformation, and corrosion resistance and mechanical strength are good. Therefore, the first and second ionization electrodes are suitable for use as preliminary ionization electrodes for devices that use corrosive gases, such as excimer laser devices.
  • the sapphire member of the present disclosure has a tube shape, and since there is no processed alteration layer on each surface region of the inner peripheral surface and the outer peripheral surface thereof, it has high corrosion resistance and has muscular bubbles arranged in a streak shape in the axial direction. Therefore, it also has the effect of absorbing and mitigating the impact and stopping the growth of cracks.
  • the sapphire member of the present disclosure can be used not only as an ionization electrode, but also as a protective tube for a long member (for example, a thermocouple, etc.), a flow path member, a dielectric member for electric discharge, an insulating member, and the like. It can be widely used in various plasma processing devices, etching devices, film forming devices, excimer laser devices, and the like.

Abstract

This ionizing electrode, which is used for a device using a corrosive gas, comprises: a tube composed of sapphire; a first electrode inserted into the tube; and a second electrode disposed outside the tube, wherein the axial direction of the tube is substantially parallel to a c-axial direction of the sapphire or is substantially perpendicular to the c-axial direction of the sapphire, and when viewed from the axial center of the tube, the second electrode is disposed in a direction substantially parallel to the c-axis of the sapphire.

Description

電離用電極およびサファイア部材Ionization electrodes and sapphire members
　本開示は、エキシマレーザ装置等に使用される電離用電極およびサファイア部材に関する。 The present disclosure relates to an ionization electrode and a sapphire member used in an excimer laser device or the like.
　エキシマレーザは、エキシマを利用したレーザである。ハロゲンガスと希ガスとを含む混合ガスを封入して放電を行うと、励起状態の希ガス・ハロゲン二量体（エキシマ）が生成し、基底状態の希ガスとハロゲンに移行する際に、エネルギーを光に変換して放出する。連続して放電を繰り返すことによって、連続したレーザを得ることができる。エキシマレーザは、封入ガスの組み合わせにより、得られるレーザ波長が変わり、ＡｒＦエキシマレーザ（波長１９３ｎｍ）、ＫｒＦエキシマレーザ(波長２４８ｎｍ)、ＸｅＣｌエキシマレーザ（波長３０８ｎｍ）、ＸｅＦエキシマレーザ（波長３５１ｎｍ）などが知られている。エキシマレーザは、半導体製造工程で使用される露光機の光源などに利用されている。 An excimer laser is a laser that uses an excimer. When a mixed gas containing a halogen gas and a rare gas is sealed and discharged, an excited rare gas / halogen dimer (excimer) is generated, and energy is generated when the gas is transferred to the base state rare gas and halogen. Is converted into light and emitted. A continuous laser can be obtained by continuously repeating the discharge. As for the excimer laser, the laser wavelength obtained varies depending on the combination of the enclosed gas, and ArF excimer laser (wavelength 193 nm), KrF excimer laser (wavelength 248 nm), XeCl excimer laser (wavelength 308 nm), XeF excimer laser (wavelength 351 nm), etc. Are known. Excimer lasers are used as light sources for exposure machines used in semiconductor manufacturing processes.
　エキシマレーザ装置では、安定なレーザ励起放電を得るために予備電離が行われる。これは、あらかじめレーザガスを電離させておくためである。予備電離電極としては、絶縁体であるチューブの内部と外部にそれぞれ第１電極および第２電極を配し、これらの電極間に電圧を印加してコロナ放電を発生させる。特許文献１には、チューブとして、多結晶または単結晶のアルミナを使用することが記載されている。 In the excimer laser device, preliminary ionization is performed in order to obtain a stable laser excitation discharge. This is because the laser gas is ionized in advance. As the preliminary ionization electrode, a first electrode and a second electrode are arranged inside and outside the tube which is an insulator, respectively, and a voltage is applied between these electrodes to generate a corona discharge. Patent Document 1 describes the use of polycrystalline or single crystal alumina as the tube.
　このような予備電離電極に使用されるチューブとしては、ハロゲンガス等の腐食性ガスの雰囲気内で放電させることから、耐腐食性や放電特性が良好であることが求められる。さらに、第１電極を挿入するため、および予備電離として適切なコロナ放電を起こさせるために、チューブは、変形が少なく、かつ機械的強度に優れていることが求められる。 The tube used for such a preliminary ionization electrode is required to have good corrosion resistance and discharge characteristics because it is discharged in an atmosphere of a corrosive gas such as a halogen gas. Further, in order to insert the first electrode and to cause an appropriate corona discharge as a preliminary ionization, the tube is required to have little deformation and excellent mechanical strength.
特開２０００－２３６１２８号公報Japanese Unexamined Patent Publication No. 2000-236128
　本開示の第１の電離用電極は、腐食性のガスを使用する装置で使用されるものであって、サファイアからなるチューブと、このチューブの内部に挿入される第１電極と、チューブの外部に配置される第２電極とを備え、チューブの軸方向は、サファイアのｃ軸方向とほぼ平行である。 The first ionization electrode of the present disclosure is used in a device using a corrosive gas, and is a tube made of sapphire, a first electrode inserted inside the tube, and the outside of the tube. The tube is provided with a second electrode arranged in the tube, and the axial direction of the tube is substantially parallel to the c-axis direction of the sapphire.
　本開示の第２の電離用電極は、腐食性のガスを使用する装置で使用されるものであって、サファイアからなるチューブと、このチューブの内部に挿入される第１電極と、チューブの外部に配置される第２電極とを備え、チューブの軸方向は、サファイアのｃ軸方向とほぼ垂直であり、チューブの軸心から見て、サファイアのｃ軸とほぼ平行な方向に第２電極が配置されている。 The second ionizing electrode of the present disclosure is used in a device using a corrosive gas, and is a tube made of sapphire, a first electrode inserted inside the tube, and the outside of the tube. The second electrode is provided with a second electrode arranged in, and the axial direction of the tube is substantially perpendicular to the c-axis direction of the sapphire, and the second electrode is substantially parallel to the c-axis of the sapphire when viewed from the axial center of the tube. Have been placed.
　本開示のサファイア部材は、腐食性のガスを使用する装置で使用されるチューブ形状であって、軸方向に延伸する内周面と外周面とを有し、内周面および外周面からそれぞれ深さ０．５ｍｍ以内の領域に加工変質層がなく、軸方向に筋状に配列した気泡を有する。 The sapphire member of the present disclosure has a tube shape used in an apparatus using a corrosive gas, has an inner peripheral surface and an outer peripheral surface extending in the axial direction, and is deep from the inner peripheral surface and the outer peripheral surface, respectively. There is no processed alteration layer in the region within 0.5 mm, and there are bubbles arranged in a streak in the axial direction.
エキシマレーザ装置における本開示の電離用電極の使用例を示す説明図である。It is explanatory drawing which shows the use example of the ionization electrode of this disclosure in an excimer laser apparatus. 本開示の電離用電極の一実施形態を示す概略断面図である。It is the schematic sectional drawing which shows one Embodiment of the ionization electrode of this disclosure. 図２Ａに示す電離用電極の概略斜視図である。It is a schematic perspective view of the ionization electrode shown in FIG. 2A. サファイアからなるチューブの製造に使用する金型の一例を示す平面図である。It is a top view which shows an example of the mold used for manufacturing the tube made of sapphire. 図３のＡ－Ａ´線部分面図である。It is a partial top view of the AA'line of FIG. 本開示のサファイア部材が有する筋状の気泡の一例を示す顕微鏡写真であるIt is a micrograph which shows an example of the streak bubble which the sapphire member of this disclosure has
　本開示の実施形態によれば、変形が少なく、耐腐食性、機械的強度、放電特性が良好な電離電極、およびこれに用いるのに好適なサファイア部材が提供される。
　以下、図面を参照して、本開示の一実施形態に係る電離用電極（第１の電離用電極）と、これに使用するサファイア部材を説明する。図１は、エキシマレーザ装置における本開示の電離用電極の使用例を示す説明図であり、図２Ａ，２Ｂは、図１に示す電離用電極の一実施形態を示す概略断面図および概略斜視図である。なお、以下の説明では、電離用電極を予備電離電極ということがある。 According to the embodiment of the present disclosure, an ionization electrode having less deformation and good corrosion resistance, mechanical strength, and discharge characteristics, and a sapphire member suitable for use thereof are provided.
Hereinafter, the ionization electrode (first ionization electrode) according to the embodiment of the present disclosure and the sapphire member used for the ionization electrode will be described with reference to the drawings. FIG. 1 is an explanatory view showing an example of use of the ionization electrode of the present disclosure in an excimer laser apparatus, and FIGS. 2A and 2B are a schematic cross-sectional view and a schematic perspective view showing an embodiment of the ionization electrode shown in FIG. Is. In the following description, the ionization electrode may be referred to as a preliminary ionization electrode.
　図１に示すように、エキシマレーザ装置は、腐食性のガスであるハロゲンガスと希ガスとを含む混合ガスを封入したチャンバ１００を備える。ハロゲンガスとしては、例えばフッ素（Ｆ２）ガス等が挙げられ、希ガスとしてはアルゴン（Ａｒ）ガス、クリプトン（Ｋｒ）ガス等が挙げられる。 As shown in FIG. 1, the excimer laser apparatus includes a chamber 100 in which a mixed gas containing a halogen gas and a rare gas, which are corrosive gases, is sealed. Examples of the halogen gas include fluorine (F 2 ) gas, and examples of the rare gas include argon (Ar) gas and krypton (Kr) gas.
　チャンバ１００内には、主電極として、レーザ光を発振させるアノード１０１とカソード１０２とが互いに対向配置されている。アノード１０１およびカソード１０２はそれぞれ紙面の垂直方向に長く延び、パルス電圧源１０３の高電圧極とアース極（いずれも図示せず）に接続されている。アース極は、例えばチャンバ１００に接続されている。アノード１０１およびカソード１０２の間に電位差をかけることによって、パルス放電Ｐ（主放電）が発生し、そのエネルギーによって紙面に垂直な方向にレーザ光が発生する。 In the chamber 100, an anode 101 for oscillating a laser beam and a cathode 102 are arranged to face each other as main electrodes. The anode 101 and the cathode 102 each extend long in the vertical direction of the paper surface and are connected to the high voltage pole and the ground pole (neither shown) of the pulse voltage source 103. The ground electrode is connected to, for example, chamber 100. By applying a potential difference between the anode 101 and the cathode 102, a pulse discharge P (main discharge) is generated, and the energy of the pulse discharge generates a laser beam in a direction perpendicular to the paper surface.
　また、チャンバ１００内には予備電離電極１０が設けられている。この予備電離電極１０は、パルス放電Ｐに先立って、上記混合ガスを電離させておく予備電離と呼ばれる放電を起こさせ、パルス放電Ｐを安定させるものである。 Further, a preliminary ionization electrode 10 is provided in the chamber 100. The preliminary ionization electrode 10 stabilizes the pulse discharge P by causing a discharge called preliminary ionization in which the mixed gas is ionized prior to the pulse discharge P.
　予備電離電極１０は、図２Ａ，２Ｂに示すように、絶縁性を有するサファイアからなるチューブ３（以下、サファイアチューブ３ということがある）と、このサファイアチューブ３の内部に挿入される第１電極１と、サファイアチューブ３の外部に配置される第２電極２とを備える。第１電極１は丸棒形状の導電体で形成される。第２電極２はプレート形状の導電体で形成される。第１電極１はパルス電圧源１０３のアース極に接続されている。 As shown in FIGS. 2A and 2B, the preliminary ionization electrode 10 includes a tube 3 made of insulating sapphire (hereinafter, may be referred to as sapphire tube 3) and a first electrode inserted inside the sapphire tube 3. 1 and a second electrode 2 arranged outside the sapphire tube 3 are provided. The first electrode 1 is formed of a round bar-shaped conductor. The second electrode 2 is formed of a plate-shaped conductor. The first electrode 1 is connected to the ground electrode of the pulse voltage source 103.
　サファイアチューブ３は、主電極の長手方向に平行に配置されている。図２Ｂに示すサファイアチューブ３は両端が開口しているが、一端が封止されたものであってもよい。また、予備電離放電による発光は、サァイアチューブ３の内周面３ａ側で発生させてもよいし、外周面３ｂ側で発生させてもよい。サファイアチューブ３は透明なので、内周面３ａ側で発生させた光を透過させることができる。 The sapphire tube 3 is arranged parallel to the longitudinal direction of the main electrode. The sapphire tube 3 shown in FIG. 2B has both ends open, but one end may be sealed. Further, the light emission due to the preliminary ionization discharge may be generated on the inner peripheral surface 3a side of the shear tube 3 or on the outer peripheral surface 3b side. Since the sapphire tube 3 is transparent, the light generated on the inner peripheral surface 3a side can be transmitted.
　サファイア（アルミナ単結晶）は異方性を有する結晶であり、例えば熱膨張率、誘電率、屈折率等の諸物性は、ｃ軸に垂直な方向とｃ軸に平行な方向とで異なっている。そのため、温度変化に伴う膨張収縮により変形したり、電圧が印加される方位によって電位の状態に違いが生じたり、光の進行方向によって速度や屈折に違いが生じたりすることがある。本開示の一実施形態では、サファイアチューブ３の軸方向、すなわち図２Ｂの矢印Ｂの方向は、サファイアのｃ軸方向とほぼ平行になっている。これにより、サファイアチューブ３の厚み方向の物性が比較的均一（等方的）になり、熱膨張による変形が少なく、誘電率も比較的均一なので、放電も均一になる。
　ここで、ｃ軸方向とほぼ平行とは、完全に平行である他に、平行な方向から±１０°程度の角度のずれは許容されることを意味する。 Sapphire (alumina single crystal) is a crystal having anisotropy. For example, various physical properties such as coefficient of thermal expansion, permittivity, and refractive index are different in the direction perpendicular to the c-axis and the direction parallel to the c-axis. .. Therefore, it may be deformed due to expansion and contraction due to a temperature change, the state of the potential may differ depending on the direction in which the voltage is applied, and the speed and refraction may differ depending on the traveling direction of light. In one embodiment of the present disclosure, the axial direction of the sapphire tube 3, that is, the direction of the arrow B in FIG. 2B is substantially parallel to the c-axis direction of the sapphire. As a result, the physical properties of the sapphire tube 3 in the thickness direction become relatively uniform (isotropic), the deformation due to thermal expansion is small, and the dielectric constant is also relatively uniform, so that the discharge becomes uniform.
Here, substantially parallel to the c-axis direction means that in addition to being completely parallel, an angle deviation of about ± 10 ° from the parallel direction is allowed.
　サファイアチューブ３は、厚さが０．５ｍｍ以上１０ｍｍ以下、好ましくは１ｍｍ以上５ｍｍ以下であるのがよい。その際、サファイアチューブ３の外径は１ｍｍ以上５０ｍｍ以下、好ましくは２ｍｍ以上２５ｍｍ以下であるのがよい。
　また、サファイアチューブ３は、全長が５００ｍｍ以上で、外周面の真直度が１．０ｍｍ以下、好ましくは０．５ｍｍ以下である。これにより、サファイアチューブ３内への第１電極１の挿入が容易になる。真直度は、例えば、以下の方法により測定することができる。定盤上に、ＪＩＳ　Ｂ７５４０に準拠した２つのＶ字ブロックを配置し、チューブ３の両端をＶ面で支持する。チューブ３をＶ面上で１回転させ、外周面３ｂが両端を結ぶ基準線から最も離れる位置での、基準線からの距離をマイクロゲージなどを用いて測定し、真直度とする。 The thickness of the sapphire tube 3 is preferably 0.5 mm or more and 10 mm or less, preferably 1 mm or more and 5 mm or less. At that time, the outer diameter of the sapphire tube 3 is preferably 1 mm or more and 50 mm or less, preferably 2 mm or more and 25 mm or less.
The total length of the sapphire tube 3 is 500 mm or more, and the straightness of the outer peripheral surface is 1.0 mm or less, preferably 0.5 mm or less. This facilitates the insertion of the first electrode 1 into the sapphire tube 3. Straightness can be measured, for example, by the following method. Two V-shaped blocks conforming to JIS B7540 are arranged on the surface plate, and both ends of the tube 3 are supported by V-planes. The tube 3 is rotated once on the V surface, and the distance from the reference line at the position where the outer peripheral surface 3b is farthest from the reference line connecting both ends is measured using a microgauge or the like to obtain straightness.
　サファイアチューブ３は、表面が平滑であるのが耐腐食性のうえで好ましい。具体的には、サファイアチューブ３の内外周面における面粗さ（算術平均粗さ）Ｓａは、１．０μｍ以下、好ましくは０．２μｍ以下であるのがよい。面粗さＳａは、ＩＳＯ２５１７８に従って、例えば、レーザ顕微鏡を用い、測定領域を５００μｍ□として測定することができる。 The surface of the sapphire tube 3 is preferably smooth in terms of corrosion resistance. Specifically, the surface roughness (arithmetic mean roughness) Sa on the inner and outer peripheral surfaces of the sapphire tube 3 is preferably 1.0 μm or less, preferably 0.2 μm or less. The surface roughness Sa can be measured according to ISO25178, for example, using a laser microscope with a measurement area of 500 μm □.
　次に、サファイアチューブ３の製造方法を説明する。サファイアチューブ３は、単結晶体を育成する方法として知られたＥＦＧ法（edge defined film fed growth法）を使用して製造することができる。ＥＦＧ法は、坩堝に充填した単結晶体の原料を加熱溶融し、坩堝内に設置した金型内のスリットによって毛細管現象を利用して、金型の上面まで上昇させたサファイア融液に種結晶（シード）を接触させ、上方に引き上げることで、所定形状の単結晶体を成長させるものである Next, the manufacturing method of the sapphire tube 3 will be described. The sapphire tube 3 can be produced by using the EFG method (edge defined film fed growth method) known as a method for growing a single crystal. In the EFG method, the raw material of the single crystal filled in the crucible is heated and melted, and the seed crystal is formed in the sapphire melt raised to the upper surface of the mold by utilizing the capillary phenomenon by the slit in the mold installed in the crucible. A single crystal having a predetermined shape is grown by bringing the (seed) into contact with the seed and pulling it upward.
　図３は、サファイアチューブ３の製造に用いる金型４を上面視した概略図であり、図４はそのＡ－Ａ´線断面図である。 FIG. 3 is a schematic view of the mold 4 used for manufacturing the sapphire tube 3 as a top view, and FIG. 4 is a cross-sectional view taken along the line AA'.
　金型４は、外周側にある環状外側金型４ａと、この環状外側金型４ａの内側に配置された内側金型４ｂとを備える。図３に示す上面視において、環状外側金型４ａと内側金型４ｂとの間には環状のスリット５が存在している。スリット５の下端が、金型４の下部に存在する融液に浸漬され、毛細管現象によって融液をスリット５の開口部６に供給する機能を有している。そのため、開口部６には融液が存在することになる。 The mold 4 includes an annular outer mold 4a on the outer peripheral side and an inner mold 4b arranged inside the annular outer mold 4a. In the top view shown in FIG. 3, an annular slit 5 exists between the annular outer mold 4a and the inner mold 4b. The lower end of the slit 5 is immersed in the melt existing in the lower part of the mold 4, and has a function of supplying the melt to the opening 6 of the slit 5 by a capillary phenomenon. Therefore, the melt is present in the opening 6.
　開口部６を取り囲むように、金型４の上面に結晶育成面７が配置されている、また、金型４の上面には、サファイアチューブ３の貫通孔に対応する位置に凹部９が形成されている。金型４の上面のうち、凹部９を除く部位、すなわち、スリット５の開口部６と結晶育成面７を合わせた領域が結晶育成領域８となる。なお、結晶育成面７はスリット５に向かって低くなるように傾斜しているが、水平な面であってもよい。 A crystal growing surface 7 is arranged on the upper surface of the mold 4 so as to surround the opening 6, and a recess 9 is formed on the upper surface of the mold 4 at a position corresponding to a through hole of the sapphire tube 3. ing. The crystal growth region 8 is a portion of the upper surface of the mold 4 excluding the recess 9, that is, a region where the opening 6 of the slit 5 and the crystal growth surface 7 are combined. The crystal growth surface 7 is inclined so as to be lower toward the slit 5, but it may be a horizontal surface.
　製造工程において、サファイア融液はスリット５を通って上昇し、開口部６に到達し、結晶育成面７まで広がって存在する。つまり、結晶育成領域８上にサファイア融液が存在する。このサファイア融液に種結晶を接触させ、ついで種結晶を、結晶育成領域８と略一致するサファイアチューブ３を製造することができる。サファイア融液は、アルミナ粉末からなるサファイア原料を、アルミナの融点以上の温度、例えば２０８０℃に加熱溶融させて得ることができる。
　なお、種結晶の断面形状は、結晶育成領域８と略同形状とするとよい。種結晶はサファイアの塊を加工して準備することができる。 In the manufacturing process, the sapphire melt rises through the slit 5, reaches the opening 6, and extends to the crystal growth surface 7. That is, the sapphire melt exists on the crystal growth region 8. The seed crystal can be brought into contact with the sapphire melt, and then the seed crystal can be produced as a sapphire tube 3 that substantially coincides with the crystal growth region 8. The sapphire melt can be obtained by heating and melting a sapphire raw material composed of alumina powder at a temperature equal to or higher than the melting point of alumina, for example, 2080 ° C.
The cross-sectional shape of the seed crystal may be substantially the same as that of the crystal growth region 8. Seed crystals can be prepared by processing sapphire lumps.
　種結晶はサファイアからなり、引き上げ方向がｃ軸となるものである。この種結晶をサファイア融液に接触させ、その状態から種結晶を引き上げることにより、得られるサファイアチューブ３は、軸方向がサファイアのｃ軸とほぼ平行になる。 The seed crystal is made of sapphire, and the pulling direction is the c-axis. By bringing this seed crystal into contact with the sapphire melt and pulling up the seed crystal from that state, the obtained sapphire tube 3 has an axial direction substantially parallel to the c-axis of the sapphire.
　これにより、得られるチューブ状のサファイア部材は厚み方向の物性が比較的均一（等方的）であり、熱膨張による変形が少なく、誘電率も比較的均一であり、放電も均一である。従って、得られるチューブ状のサファイア部材は、エキシマレーザ装置におけるサファイアチューブ３として好適である。
　なお、チューブ３の軸方向がサファイアのｃ軸とほぼ平行であることは、Ｘ線回折法を用いた結晶方位測定により確認することができる。 As a result, the obtained tubular sapphire member has relatively uniform (isotropic) physical properties in the thickness direction, is less deformed due to thermal expansion, has a relatively uniform dielectric constant, and has a uniform discharge. Therefore, the obtained tubular sapphire member is suitable as the sapphire tube 3 in the excimer laser apparatus.
It can be confirmed by measuring the crystal orientation using the X-ray diffraction method that the axial direction of the tube 3 is substantially parallel to the c-axis of sapphire.
　サファイアチューブ３として使用されるサファイア部材は、図２Ａに示すように、軸方向に延伸する内周面３ａと外周面３ｂとを有し、内周面３ａと外周面３ｂからそれぞれ深さ０．５ｍｍ以内の領域に加工変質層がなく、前記軸方向に筋状に配列した気泡を有する。加工変質層とは、切削、研削、研磨などの機械的加工によって、結晶表面にマイクロクラック、転位などの結晶欠陥が導入された層と定義することができ、具体的には、バルク部分よりもマイクロクラック、転位などが多い（例えば１０倍以上の）表面層を指す。
　加工変質層が内周面３ａと外周面３ｂからそれぞれ深さ０．５ｍｍ以内の領域に存在すると、耐腐食性が低くなるとともに、パーティクルが発生しやすくなる。加工変質層が深さ０．５ｍｍ以内の領域に存在するか否かは、例えば、光学顕微鏡観察、ＣＬ(カソードルミネッセンス)観察、ＴＥＭ（透過型電子顕微鏡）観察によって確認することができる。
　内周面３ａと外周面３ｂに加工変質層がないサファイアチューブ３は、育成したチューブ状サファイア結晶の内周面３ａと外周面３ｂを、機械加工を施さず、いわゆるアズグロウン（as-grown）面とすることで作製することができる。 As shown in FIG. 2A, the sapphire member used as the sapphire tube 3 has an inner peripheral surface 3a and an outer peripheral surface 3b extending in the axial direction, and has a depth of 0. There is no processed alteration layer in the region within 5 mm, and the bubbles are arranged in a streak pattern in the axial direction. A work-altered layer can be defined as a layer in which crystal defects such as microcracks and dislocations are introduced into the crystal surface by mechanical processing such as cutting, grinding, and polishing. Specifically, it is more than a bulk portion. Refers to a surface layer with many microcracks, dislocations, etc. (for example, 10 times or more).
If the work-altered layer is present in a region within 0.5 mm in depth from the inner peripheral surface 3a and the outer peripheral surface 3b, respectively, the corrosion resistance is lowered and particles are likely to be generated. Whether or not the processed altered layer exists in a region having a depth of 0.5 mm or less can be confirmed by, for example, optical microscope observation, CL (cathodoluminescence) observation, and TEM (transmission electron microscope) observation.
In the sapphire tube 3 having no processed alteration layer on the inner peripheral surface 3a and the outer peripheral surface 3b, the inner peripheral surface 3a and the outer peripheral surface 3b of the grown tubular sapphire crystal are not machined, and the so-called as-grown surface is not processed. It can be produced by.
　また、サファイア部材の内周面３ａと外周面３ｂからそれぞれ深さ０．５ｍｍ以内の領域に、チューブ３の軸方向に筋状に配列した気泡を有する。図５はサファイアチューブ３の外周面に発生した筋状の気泡の一例を示している。この筋状の気泡によって、サファイアチューブ３に対する機械的衝撃や熱衝撃等による衝撃を吸収し、緩和すると共に、クラックの伸展を止めることができる。
　筋状の気泡は、金型４の表面からチューブ３を引き上げる際の育成条件（引き上げ速度、雰囲気、育成温度など）や育成装置の構成や形状（結晶育成面７の形状や傾斜角など）を調整することによって発生させる（または発生状況を制御する）ことができる。筋状の気泡は、例えば直径５μｍ～４０μｍ程度で、チューブ３の周方向に１個から数個並んで軸方向に筋状に配列している。１つの筋の幅は、例えば、３００μｍ以下であり、チューブ３の周方向に複数本の筋状で配列している。各筋間のピッチは、例えば０．３ｍｍ～２ｍｍ程度である。外周面または内周面から見た、単位面積当たりの気泡の密度は２５０～２５００個／ｍｍ２である。気泡の密度は、例えば、筋状の気泡１ｂが含まれる領域内の気泡１ｂの数を計測し、計測領域の面積で除すことで求められる。 Further, the sapphire member has bubbles arranged in a streak pattern in the axial direction of the tube 3 in regions within 0.5 mm in depth from the inner peripheral surface 3a and the outer peripheral surface 3b, respectively. FIG. 5 shows an example of streaky bubbles generated on the outer peripheral surface of the sapphire tube 3. The streaky bubbles can absorb and mitigate the impact of the mechanical impact, thermal impact, etc. on the sapphire tube 3 and stop the expansion of cracks.
The streaky bubbles determine the growing conditions (pulling speed, atmosphere, growing temperature, etc.) when pulling the tube 3 from the surface of the mold 4 and the configuration and shape of the growing device (shape, inclination angle, etc. of the crystal growing surface 7). It can be generated (or the status of occurrence is controlled) by adjusting. The streaky bubbles have a diameter of, for example, about 5 μm to 40 μm, and one to several streaky bubbles are arranged in the circumferential direction of the tube 3 and arranged in a streak shape in the axial direction. The width of one muscle is, for example, 300 μm or less, and a plurality of muscles are arranged in the circumferential direction of the tube 3. The pitch between the muscles is, for example, about 0.3 mm to 2 mm. The density of bubbles per unit area as seen from the outer peripheral surface or the inner peripheral surface is 250 to 2500 cells / mm 2 . The density of bubbles is determined, for example, by measuring the number of bubbles 1b in the region containing the streaky bubbles 1b and dividing by the area of the measurement area.
　次に、本開示の他の実施形態に係る電離用電極（第２の電離用電極）を説明する。第２の電離用電極が、上述した第１の電離用電極と異なるのは、サファイアのｃ軸が図２Ａの矢印Ａとほぼ平行となっており、サファイアチューブ３の軸方向、すなわち図２Ｂの矢印Ｂの方向が、サファイアのｃ軸方向とほぼ垂直であり、チューブ３の軸心から見て、サファイアのｃ軸とほぼ平行な方向、すなわち図２Ａの矢印Ａの方向に第２電極２が配置されている点であり、その他は第１の電離用電極と同様である。 Next, the ionization electrode (second ionization electrode) according to another embodiment of the present disclosure will be described. The difference between the second ionizing electrode and the first ionizing electrode described above is that the c-axis of the sapphire is substantially parallel to the arrow A in FIG. 2A, and the axial direction of the sapphire tube 3, that is, FIG. 2B. The direction of the arrow B is substantially perpendicular to the c-axis direction of the sapphire, and the second electrode 2 is located in the direction substantially parallel to the c-axis of the sapphire when viewed from the axis of the tube 3, that is, in the direction of the arrow A in FIG. 2A. It is the same as the first ionizing electrode except that it is arranged.
　ここで、サファイアのｃ軸方向とほぼ垂直であるとは、完全に垂直である他に、垂直方向から±１０°程度の角度のずれは許容されることを意味する。また、サファイアのｃ軸とほぼ平行な方向とは、完全に平行である他に、平行な方向から±１０°程度の角度のずれは許容されることを意味する。 Here, being substantially perpendicular to the c-axis direction of sapphire means that in addition to being completely vertical, a deviation of about ± 10 ° from the vertical direction is allowed. Further, the direction substantially parallel to the c-axis of sapphire means that in addition to being completely parallel, a deviation of about ± 10 ° from the parallel direction is allowed.
　サファイアのｃ軸方向は、誘電率が高いので、腐食性ガスを含む気体中の電解が強くなり、放電しやすくなる。サファイアチューブ３の軸方向をサファイアのｃ軸とほぼ垂直にするには、前記したサファイアの製造方法において、種結晶のｃ軸を引き上げ方向に対してほぼ垂直になるように配置し、その状態でサファイア融液を引き上げるようにすればよい。
　サファイアチューブ３の軸方向がサファイアのｃ軸とほぼ垂直であることは、Ｘ線回折法を用いた結晶方位測定により確認することができる。
　その他は、第１の電離電極と同じである。すなわち、本実施形態に係る第２の電離用電極で使用されるサファイア部材も、内周面３ａと外周面３ｂからそれぞれ深さ０．５ｍｍ以内の領域に加工変質層がなく、前記軸方向に筋状に配列した気泡を有する。 Since the dielectric constant of sapphire is high in the c-axis direction, electrolysis in a gas containing a corrosive gas becomes strong, and it becomes easy to discharge. In order to make the axial direction of the sapphire tube 3 substantially perpendicular to the c-axis of sapphire, in the above-mentioned method for producing sapphire, the c-axis of the seed crystal is arranged so as to be substantially perpendicular to the pulling direction, and in that state. The sapphire melt may be pulled up.
It can be confirmed by the crystal orientation measurement using the X-ray diffraction method that the axial direction of the sapphire tube 3 is substantially perpendicular to the c-axis of the sapphire.
Others are the same as the first ionization electrode. That is, the sapphire member used in the second ionization electrode according to the present embodiment also has no processing alteration layer in the regions within 0.5 mm in depth from the inner peripheral surface 3a and the outer peripheral surface 3b, respectively, and is in the axial direction. It has bubbles arranged in a streak pattern.
　以上のように、本開示の第１および第２の電離用電極は、いずれもサファイアからなるチューブを備えるので、変形が少なく、耐腐食性、機械的強度が良好である。従って、第１および第２の電離用電極は、腐食性のガスを使用する装置、例えばエキシマレーザ装置の予備電離電極として使用するのに好適である。
　本開示のサファイア部材は、チューブ形状であり、その内周面および外周面の各表面領域に加工変質層がないので、耐腐食性が高く、かつ軸方向に筋状に配列した筋泡を有するので、衝撃を吸収、緩和し、クラックの伸展を止める効果もある。 As described above, since the first and second ionization electrodes of the present disclosure both include a tube made of sapphire, there is little deformation, and corrosion resistance and mechanical strength are good. Therefore, the first and second ionization electrodes are suitable for use as preliminary ionization electrodes for devices that use corrosive gases, such as excimer laser devices.
The sapphire member of the present disclosure has a tube shape, and since there is no processed alteration layer on each surface region of the inner peripheral surface and the outer peripheral surface thereof, it has high corrosion resistance and has muscular bubbles arranged in a streak shape in the axial direction. Therefore, it also has the effect of absorbing and mitigating the impact and stopping the growth of cracks.
　以上、本開示の実施形態について説明したが、本開示は上記の実施形態のみに限定されるものではなく、請求の範囲に記載の範囲内で種々な変更や改良が可能である。例えば、本開示のサファイア部材は、電離用電極としての用途の他、長尺部材（例えば熱電対等）の保護管、流路部材、放電用の誘電部材、絶縁部材等としても利用可能であり、各種のプラズマ処理装置、エッチング装置、成膜装置、エキシマレーザ装置等に広く使用することができる。 Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various changes and improvements can be made within the scope of the claims. For example, the sapphire member of the present disclosure can be used not only as an ionization electrode, but also as a protective tube for a long member (for example, a thermocouple, etc.), a flow path member, a dielectric member for electric discharge, an insulating member, and the like. It can be widely used in various plasma processing devices, etching devices, film forming devices, excimer laser devices, and the like.
１　  第１電極
　１ｂ　筋状の気泡
２　　第２電極
３　　チューブ（サファイアチューブ）
　３ａ　内周面
　３ｂ　外周面
４　　金型
　４ａ　環状金型
　４ｂ　内側金型
５　　スリット
６　　開口部
７　　結晶育成面
８　　結晶育成領域
１０　予備電離電極（電離用電極）
１００　　チャンバ
１０１　　アノード
１０２　　カソード
１０３　　パルス電圧源
  1 1st electrode 1b Streaky bubbles 2 2nd electrode 3 Tube (sapphire tube)
3a Inner peripheral surface 3b Outer surface 4 Mold 4a Circular mold 4b Inner mold 5 Slit 6 Opening 7 Crystal growth surface 8 Crystal growth region 10 Preliminary ionization electrode (ionization electrode)
100 Chamber 101 Anode 102 Cathode 103 Pulse voltage source

Claims (5)

  1. 　腐食性のガスを使用する装置で使用される電離用電極であって、
    　サファイアからなるチューブと、前記チューブの内部に挿入される第１電極と、前記チューブの外部に配置される第２電極とを備え、
    　前記チューブの軸方向は、サファイアのｃ軸方向とほぼ平行である、電離用電極。     An ionizing electrode used in equipment that uses corrosive gas.
    A tube made of sapphire, a first electrode inserted inside the tube, and a second electrode arranged outside the tube are provided.
    An ionization electrode whose axial direction of the tube is substantially parallel to the c-axis direction of sapphire.
  2. 　腐食性のガスを使用する装置で使用される電離用電極であって、
    　サファイアからなるチューブと、前記チューブの内部に挿入される第１電極と、前記チューブの外部に配置される第２電極とを備え、
    　前記チューブの軸方向は、サファイアのｃ軸方向とほぼ垂直であり、前記チューブの軸心から見て、サファイアのｃ軸とほぼ平行な方向に前記第２電極が配置されている、電離用電極。     An ionizing electrode used in equipment that uses corrosive gas.
    A tube made of sapphire, a first electrode inserted inside the tube, and a second electrode arranged outside the tube are provided.
    The axial direction of the tube is substantially perpendicular to the c-axis direction of the sapphire, and the second electrode is arranged in a direction substantially parallel to the c-axis of the sapphire when viewed from the axial center of the tube. ..
  3. 　前記チューブは全長が５００ｍｍ以上で、外周面の真直度が１．０ｍｍ以下である、請求項１または２に記載の電離用電極。 The ionization electrode according to claim 1 or 2, wherein the tube has a total length of 500 mm or more and an outer peripheral surface straightness of 1.0 mm or less.
  4. 　前記電離用電極が、ハロゲンガスおよび希ガスを用いるエキシマレーザ装置用の予備電離電極である、請求項１乃至３のいずれかに記載の電離用電極。 The ionization electrode according to any one of claims 1 to 3, wherein the ionization electrode is a preliminary ionization electrode for an excimer laser apparatus using a halogen gas and a rare gas.
  5. 　腐食性のガスを使用する装置で使用される、チューブ形状のサファイア部材であって、軸方向に延伸する内周面と外周面とを有し、
    　前記内周面および前記外周面からそれぞれ深さ０．５ｍｍ以内の領域に加工変質層がなく、前記軸方向に筋状に配列した気泡を有する、サファイア部材。
     
          A tube-shaped sapphire member used in equipment that uses corrosive gas, which has an inner peripheral surface and an outer peripheral surface extending in the axial direction.
    A sapphire member having no processed alteration layer in regions within 0.5 mm in depth from the inner peripheral surface and the outer peripheral surface, respectively, and having bubbles arranged in a streak pattern in the axial direction.
PCT/JP2020/044103 2019-11-27 2020-11-26 Ionizing electrode and sapphire member WO2021107049A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS51102379A (en) * 1975-03-07 1976-09-09 Hitachi Ltd HODENTO
JP2000236128A (en) * 1999-02-10 2000-08-29 Lambda Physik G Zur Herstellung Von Lasern Mbh Gas laser pre-ionization device
US20110275546A1 (en) * 2008-12-12 2011-11-10 Instituto Mexicano Del Petroleo Foaming composition for high temperature and salinity
WO2018181981A1 (en) * 2017-03-30 2018-10-04 京セラ株式会社 Tubular sapphire member, heat exchanger, semiconductor manufacturing device and method for manufacturing tubular sapphire member

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS51102379A (en) * 1975-03-07 1976-09-09 Hitachi Ltd HODENTO
JP2000236128A (en) * 1999-02-10 2000-08-29 Lambda Physik G Zur Herstellung Von Lasern Mbh Gas laser pre-ionization device
US20110275546A1 (en) * 2008-12-12 2011-11-10 Instituto Mexicano Del Petroleo Foaming composition for high temperature and salinity
WO2018181981A1 (en) * 2017-03-30 2018-10-04 京セラ株式会社 Tubular sapphire member, heat exchanger, semiconductor manufacturing device and method for manufacturing tubular sapphire member

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