Abstract: When compound semiconductor layers are formed on a compound semiconductor substrate (40) by sequentially layering group III nitride semiconductor crystalline layers by metal organic chemical vapor deposition method, the compound semiconductor substrate (40) is attached inside of a reaction container with the crystal growth surface thereof facing upward, a protection member (60) having plural grooves (63) formed in a radiating manner on the side facing the crystal growth surface is attached above the compound semiconductor substrate (40), and a material gas is supplied to the inside of the reaction container through a first through hole (61) provided in the center of the protection member (60). Thereby, in the manufacture of a compound semiconductor using metal organic chemical vapor deposition method, a decrease in yield caused by adhesion of peeled-off reaction byproducts to the substrate or to the epitaxially grown film on the substrate is suppressed.

Abstract: A shield assembly for a sputter deposition chamber, the shield assembly including an outer sleeve with a gas inlet to conduct a gas through the outer sleeve and an inner sleeve disposed within the outer sleeve, the inner sleeve including gas channels on a surface mating with the outer sleeve to conduct the gas between the inner and outer sleeves. The shield assembly may further include an aperture ring adjacent to a first end of both the inner and outer sleeves, the aperture ring including a plurality of gas outlets to conduct the gas from the gas channels and an inner aperture flange extending from the plurality of gas outlets and adjacent to gas shield flange to form a gas runway for conducting the gas toward a sputter target located within the deposition chamber.

Abstract: A hard mask film 2 provided on substrate 1 is formed by tin-containing chromium-containing material. In the chromium-containing material including tin, which forms the hard mask film 2, the etching resistance to fluorine-containing dry etching is equal to or higher than the etching resistance of the tin-free chromium-containing material, and it shows a significantly high etching rate as compared with a chromium-containing material free of tin under conditions for chlorine-containing dry etching. As a result, the time for chlorine-containing dry etching is shortened, and damage to a resist pattern is reduced. Thus, high-precision pattern transfer can be performed. The present invention provides a novel technique for increasing etching process-ability by increasing a dry-etching rate of a hard mask film made of a chromium-containing material while assuring a hard mask function of the hard mask film.

Abstract: An edge ring assembly surrounds a substrate support surface in a plasma etching chamber. The edge ring assembly comprises an edge ring and a dielectric spacer ring. The dielectric spacer ring, which surrounds the substrate support surface and which is surrounded by the edge ring in the radial direction, is configured to insulate the edge ring from the baseplate. Incorporation of the edge ring assembly around the substrate support surface can decrease the buildup of polymer at the underside and along the edge of a substrate and increase plasma etching uniformity of the substrate.

Abstract: A plasma processing chamber configured for cleaning a bevel edge of a substrate is provided. The chamber includes a top edge electrode surrounding an insulating plate, and the insulator plate opposes a bottom electrode. The top edge electrode is electrically grounded and separated from the insulator plate by a top dielectric ring. The chamber also includes a bottom edge electrode that is electrically grounded and surrounds the bottom electrode and is separated from the bottom electrode by a bottom dielectric ring. The bottom edge electrode is oriented to oppose the top edge electrode, and the bottom edge electrode has an L shape that is up-facing. Bevel edge plasma processing of a substrate edge is configured to be processed in a chamber having the top and bottom edge electrodes.

Abstract: A resin composition for photoimprinting, a cured product of the resin composition which is excellent in etching and heat resistance, and a pattern forming process using the resin composition are provided. The resin composition contains photocurable monomer (A) containing at least one carbazole compound of formula (I): a photocurable monomer (B) containing at least one compound of the following formulae (II), (III), and (IV): and a photopolymerization initiator (C). The weight ratio of the photocurable monomer (A) to the photocurable monomer (B) is from 30/70 to 87/13.

Abstract: A method and apparatus for etching photomasks is provided herein. In one embodiment, the apparatus comprises a process chamber having a support pedestal adapted for receiving a photomask. An ion-neutral shield is disposed above the pedestal and a deflector plate assembly is provided above the ion-neutral shield. The deflector plate assembly defines a gas flow direction for process gases towards the ion-neutral shield, while the ion-neutral shield is used to establish a desired distribution of ion and neutral species in a plasma for etching the photomask.

Abstract: Included within the scope of the invention are plasma etch-resistant films for substrates. The films include a yttria material and a at least a portion of the yttria material is in a crystal phase having an orientation defined by a Miller Index notation {111}. Also included are methods of manufacturing plasma etch-resistant films on a substrate. Such methods include applying a yttria material-containing composition onto at least a portion of a surface of a substrate to form a film. The film includes a yttria material and at least a portion of the yttria material is in a crystal phase having an orientation defined by a Miller Index notation {111}.

Abstract: An arrangement for supporting substrates during processing, having a wafer carrier with a susceptor for supporting the substrate and confining the substrate to predetermined position. An inner mask is configured for placing on top of the substrate, the inner mask having an opening pattern to mask unprocessed parts of the substrate, but expose remaining parts of the substrate for processing. An outer mask is configured for placing on top of the inner mask, the outer mask having an opening that exposes the part of the inner mask having the opening pattern, but cover the periphery of the inner mask.

Abstract: A shadow mask, a method of manufacturing the shadow mask, and a method of forming a thin film using the shadow mask are provided. The shadow mask includes an upper layer and a lower layer. The upper layer includes a first opening. The lower layer is formed on a lower surface of the upper layer around the first opening and includes an opening having the same size as the first opening. When the thin film is formed using the shadow mask, the lower layer of the shadow mask is close to the edge of a cavity of a substrate, and a position on which the thin film may be formed as defined by the lower layer of the shadow mask. Therefore, the thickness of the thin film can be uniform.

Abstract: A plasma etching method for plasma etching, in a processing chamber, an antireflection film laminated on an organic film formed on a substrate by using an etching mask made of a resist film formed on the antireflection film, the plasma etching method includes: depositing a Si-containing compound on the etching mask made of the resist film by using plasma of Si-containing gas in the processing chamber; and etching the antireflection film in a state where the Si-containing compound is deposited on the etching mask.

Abstract: An atmospheric plasma irradiation unit has a discharge tube for ejecting a primary plasma formed of an inductively coupled plasma of an inert gas and a mixer for generating a secondary plasma formed of a mixed gas plasmanized by collisions of the primary plasma with a mixed gas region of a second inert gas and a reactive gas. The discharge tube and the mixer are included in a plasma head. A moving unit moves the plasma head so that an irradiation area of the secondary plasma to an object is moved on a circular or other-shaped locus.

Abstract: The present invention provides a method for plasma dicing a substrate. The method comprising providing a process chamber having a wall; providing a plasma source adjacent to the wall of the process chamber; providing a work piece support within the process chamber; placing the substrate onto a support film on a frame to form a work piece work piece; loading the work piece onto the work piece support; providing a cover ring disposed above the work piece; generating a plasma through the plasma source; and etching the work piece through the generated plasma.

Abstract: A method for patterning a plurality of features in a non-rectangular pattern, such as on an integrated circuit device, includes providing a substrate including a surface with a plurality of elongated protrusions, the elongated protrusions extending in a first direction. A first layer is formed above the surface and above the plurality of elongated protrusions, and patterned with an end cutting mask. The end cutting mask includes two nearly-adjacent patterns with a sub-resolution feature positioned and configured such that when the resulting pattern on the first layer includes the two nearly adjacent patterns and a connection there between. The method further includes cutting ends of the elongated protrusions using the pattern on the first layer.

Abstract: This etching method comprises a step for forming an organic compound gas (22) atmosphere around a copper film (101) that has a mask material (102) formed on the surface thereof and a step for using the mask material (102) as a mask on the copper film (101), irradiating with oxygen ions (6), and performing anisotropic etching of the copper film (101) in the organic compound gas (22) atmosphere.

Abstract: The invention relates to a masking system for masking a cylinder bore (2) of a combustion engine (3) during a thermal coating procedure including a masking body (4) which can be placed during the thermal coating of a first cylinder (5) of the combustion engine (3) in the cylinder bore (2) of a second cylinder (7) to cover a cylinder wall (6) of the second cylinder (7). In this arrangement the masking body (4) is designed in such a way that a flow gap (10) of predeterminable breadth can be set between the masking body (4) and the cylinder wall (6) of the second cylinder (7) for the production of a flow (8) of a fluid (9).

Abstract: An apparatus for fabrication of microscopic structures that uses a beam process, such as beam-induced decomposition of a precursor, to deposit a mask in a precise pattern and then a selective, plasma beam is applied, comprising the steps of first creating a protective mask upon surface portions of a substrate using a beam process such as an electron beam, focused ion beam (FIB), or laser process, and secondly etching unmasked substrate portions using a selective plasma beam etch process. Optionally, a third step comprising the removal of the protective mask may be performed with a second, materially oppositely selective plasma beam process.

Abstract: A more uniform plasma process is implemented for treating a treatment object using an inductively coupled plasma source which produces an asymmetric plasma density pattern at the treatment surface using a slotted electrostatic shield having uniformly spaced-apart slots. The slotted electrostatic shield is modified in a way which compensates for the asymmetric plasma density pattern to provide a modified plasma density pattern at the treatment surface. A more uniform radial plasma process is described in which an electrostatic shield arrangement is configured to replace a given electrostatic shield in a way which provides for producing a modified radial variation characteristic across the treatment surface. The inductively coupled plasma source defines an axis of symmetry and the electrostatic shield arrangement is configured to include a shape that extends through a range of radii relative to the axis of symmetry.

Abstract: Methods of treating a target surface of an article having one or more passageways includes fluidly connecting a pressure masker including pressurized masking fluid to a first side of at least one passageway, passing the pressurized masking fluid through the at least one passageway from the first side to a second side having the target surface, and treating the target surface of the article using a surface treatment system that disposes a surface treating material on the target surface, wherein the pressurized masking fluid passing through the at least one passageway prevents the surface treating material from permanently altering a cross sectional area of the at least one passageway.

Abstract: An atomic layer deposition apparatus includes a chamber, a vacuum pump to control a pressure in the chamber, a gas supply unit to supply a reaction gas into the chamber, a substrate holder disposed between the vacuum pump and the gas supply unit and having a heater, a mask assembly disposed between the substrate holder and the gas supply unit and having a cooling path to move coolant, and a coolant source to supply the coolant into the cooling path. The mask assembly is positioned a first distance from a substrate, and coolant is supplied into the cooling path of the mask assembly. The substrate is heated using the heater of the substrate holder, a pressure of the chamber is controlled using the vacuum pump, and reaction gasses are sequentially supplied through the gas supply unit.

Abstract: A BEOL e-fuse is disclosed which reliably blows in the via and can be formed even in the tightest pitch BEOL layers. The BEOL e-fuse can be formed utilizing a line first dual damascene process to create a sub-lithographic via to be the programmable link of the e-fuse. The sub-lithographic via can be patterned using standard lithography and the cross section of the via can be tuned to match the target programming current.

Abstract: The present disclosure provides for methods of fabricating a metal hard mask and a metal hard mask fabricated by such methods. A method includes flowing at least one metal reactant gas into a reaction chamber configured to perform chemical vapor deposition (CVD), wherein the at least one metal reactant gas includes a metal-halogen gas or a metal-organic gas. The method further includes depositing a hard mask metal layer by CVD using the at least one metal reactant gas.

Abstract: A plasma etch processing chamber configured to clean a bevel edge of a substrate is provided. The chamber includes a bottom edge electrode and a top edge electrode defined over the bottom edge electrode. The top edge electrode and the bottom edge electrode are configured to generate a cleaning plasma to clean the bevel edge of the substrate. The chamber includes a gas feed defined through a top surface of the processing chamber. The gas feed introduces a processing gas for striking the cleaning plasma at a location in the processing chamber that is between an axis of the substrate and the top edge electrode. A pump out port is defined through the top surface of the chamber and the pump out port located along a center axis of the substrate. A method for cleaning a bevel edge of a substrate is also provided.

Abstract: A chamber for combinatorially processing a substrate is provided. The chamber includes a first mask and a second mask that share a common central axis. The first mask and the second mask are independently rotatable around the common central axis. The first mask has a first plurality of radial apertures and the second mask has a second plurality of radial apertures. An axis of the first plurality of radial apertures is offset from an axis of the second plurality of radial apertures. A substrate support that is operable to support a substrate below the first and second masks is included. The substrate support shares the common central axis.

Abstract: An apparatus for etching a substrate includes: a chamber; a susceptor in the chamber, the susceptor including at least one loading portion corresponding to at least one substrate; a gas supply over the susceptor, the gas supply including a hollow and at least one through hole corresponding to the at least one loading portions; and at least one shielding means interposed into the at least one through holes, the at least one shielding means including a body part and a hanging part on the body part, the body part having a cross-sectional area smaller than the at least one through holes, and the hanging part outwardly protruding from the body part, wherein the at least one shielding means is suspended on the gas supply by the hanging part, and wherein the body part shields a central portion of the at least one substrate and exposes an edge portion of the at least one substrate.

Abstract: A jig for use in etching supports an etching target while an etching process is performed and surrounds a remaining region of the etching target except for a portion of the etching target, so as to expose the portion of the etching target. Accordingly, a stable support of the etching target during the etching process may be provided, and thus an etching of an undesired region may be prevented, and a stable production yield may be accomplished.

Abstract: Chambers for processing a bevel edge of a substrate are provided. One such chamber includes a bottom electrode defined to support a substrate in the chamber. The bottom electrode has a bottom first level for supporting the substrate and a bottom second level near an outer edge of bottom electrode. The bottom second level is defined at a step below the bottom first level. Further included is a top electrode oriented above the bottom electrode. The top electrode having a top first level and a top second level, where the top first level is opposite the bottom first level and the top second level is opposite the bottom second level. The top second level is defined at a step above the top first level. A bottom ring mount oriented at the bottom second level is included. The bottom ring mount includes a first adjuster for moving a bottom permanent magnet toward and away from the top electrode. Further included is a top ring mount oriented at the top second level.

Abstract: In some embodiments, the present invention discloses sealing mechanisms for generating site isolated regions on a substrate, allowing combinatorial processing without cross contamination between regions. The sealing mechanism can include a thin sharp edge ring for pressing on the substrate surface with small contact area. The small sealing area can concentrate the sealing force, generating higher contact pressure to guard against fluid leakage across the sealing surface, for example, eliminating fluid wicking at the seal interface through capillary action. The sealing mechanism can include multiple protrusions, which contacts the substrate leaving a small gap at the remaining portion of the sealing mechanism. The sealing mechanism can include minimal contact points with the substrate, which can significantly reduce the particle generation during processing. A pressure differential can be established across the sealing surface to prevent fluid leakage.

Abstract: Provided is a mask blank which is used for manufacturing an imprinting mold and which may form a fine mold pattern with high pattern accuracy. A mask blank (10) includes a transparent substrate (1) and a thin film (2) contacted with a surface of the substrate. The thin film (2) includes a laminated film including an upper layer (4) which is composed of a material containing silicon (Si) or a material containing tantalum (Ta), and a lower layer (3) which is composed of a material containing at least one of hafnium (Hf) and zirconium (Zr) and containing substantially no oxygen.

Abstract: A protective chuck is disposed on a substrate with a gas bearing layer between the bottom surface of the protective chuck and the substrate surface. The gas bearing layer protects a surface region against a fluid layer covering the substrate surface. The protection of the gas bearing is a non-contact protection, reducing or eliminating potential damage to the substrate surface due to friction. The gas bearing can enable combinatorial processing of a substrate, providing multiple isolated processing regions on a single substrate with different material and processing conditions.

Abstract: A radical passing device can selectively pass only radicals from plasma securely. In a chamber 11 of a substrate processing apparatus 10, a radical filter 14 provided between a wafer W mounted on a mounting table 12 and a plasma generator 13 includes a upper shield plate 17 and a lower shield plate 18 positioned opposite to the plasma generator 13 with the upper shield plate 17 therebetween. Further, the upper shield plate 17 has a multiple number of upper through holes 17a formed in a thickness direction thereof, and the lower shield plate 18 has a multiple number of lower through holes 18a formed in a thickness direction thereof. Furthermore, a negative DC voltage is applied to the upper shield plate 17, and a positive DC voltage is applied to the lower shield plate 18.

Abstract: According to one embodiment, a method for patterning a medium having a patterned hard mask applied thereon is disclosed herein. The patterned hard mark includes a plurality of apertures exposing portions of the medium. The method includes directing ions toward the medium, implanting a portion of the ions into the exposed portions of the medium, removing a layer of the patterned hard mask with another portion of the ions, and depositing hard mask material onto the patterned hard mask. Depositing hard mask material onto the exposed portions of the medium may follow implantation of the portion of the ions into the exposed portions of the medium.

Abstract: Embodiments of the present disclosure relate to display devices and electronic devices incorporating a data line distribution segment between neighboring pixel electrodes. Specifically, embodiments of the present disclosure employ a uniformly distributed data line distribution segment coupled to a data line so as to cause a substantially uniform data line-to-pixel electrode capacitance with the neighboring pixel electrodes even when the data line is disposed closer to one of the neighboring pixel electrodes than the other.

Abstract: A method of reducing roughness in an opening in a surface of a resist material disposed on a substrate, comprises generating a plasma having a plasma sheath and ions therein. The method also includes modifying a shape of a boundary defined between the plasma and the plasma sheath with a plasma sheath modifier so that a portion of the boundary facing the resist material is not parallel to a plane defined by the surface of the substrate. The method also includes providing a first exposure of ions while the substrate is in a first position, the first exposure comprising ions accelerated across the boundary having the modified shape toward the resist material over an angular range with respect to the surface of the substrate.

Abstract: A patterned surface for improving the growth of semiconductor layers, such as group III nitride-based semiconductor layers, is provided. The patterned surface can include a set of substantially flat top surfaces and a plurality of openings. Each substantially flat top surface can have a root mean square roughness less than approximately 0.5 nanometers, and the openings can have a characteristic size between approximately 0.1 micron and five microns.

Abstract: Aspects of the present invention are directed to a mask holder for especially large-surface substrates, especially for the micro-structuring of organic electroluminescent materials (OLED) for the production of OLED screens, displays and the like by means of vacuum-coating processes, with a substrate carrier for receiving the substrate during coating processes, with the substrate carrier comprising one or more magnets and the mask features a frame of magnetic material, such that the frame of the mask is held by means of the magnets of the substrate carrier relative to the substrate to be coated.

Abstract: Methods for forming a nanoperforated graphene material are provided. The methods comprise forming an etch mask defining a periodic array of holes over a graphene material and patterning the periodic array of holes into the graphene material. The etch mask comprises a pattern-defining block copolymer layer, and can optionally also comprise a wetting layer and a neutral layer. The nanoperforated graphene material can consist of a single sheet of graphene or a plurality of graphene sheets.

Abstract: Methods of dicing substrates having a plurality of ICs. A method includes forming a mask comprising a water soluble material layer over the semiconductor substrate. The mask is patterned with a femtosecond laser scribing process to provide a patterned mask with gaps. The patterning exposes regions of the substrate between the ICs. The substrate is then etched through the gaps in the patterned mask to singulate the IC and the water soluble material layer washed off.

Abstract: Methods of dicing substrates having a plurality of ICs. A method includes forming a multi-layered mask comprising a first mask material layer soluble in a solvent over the semiconductor substrate and a second mask material layer, insoluble in the solvent, over the first mask material layer. The multi-layered mask is patterned with a laser scribing process to provide a patterned mask with gaps. The patterning exposes regions of the substrate between the ICs. The substrate is then plasma etched through the gaps in the patterned mask to singulate the IC with the second mask material layer protecting the first mask material layer for at least a portion of the plasma etch. The soluble material layer is dissolved subsequent to singulation to remove the multi-layered mask.

Abstract: An apparatus for the plasma treatment of molds (2), in particular for contact lens molds, comprises a treatment chamber (50), in which a first electrode (51) is arranged facing a carrier (1;4) for carrying the molds (2) to be treated. The carrier (1;4) forms the second electrode (52) and comprises a first metal plate (10;40) having holes (100;400) therein and a second metal plate (11;41) which is arranged spaced apart from the first metal plate (10;40), and which is connected to the first metal plate (10;40) in an electrically conductive manner (12,13;43). The molds (2) are arranged on the second metal plate (11;41) with their molding surfaces (210) facing towards the first electrode (51) and are exposable to plasma through the holes (100;400) in the first metal plate (10;40).

Abstract: Embodiments of the present invention generally relate to a method and apparatus for plasma etching substrates and, more specifically, to a method and apparatus with protection for edges, sides and backs of the substrates being processed. Embodiments of the present invention provide an edge protection plate with an aperture smaller in size than a substrate being processed, wherein the edge protection plate may be positioned in close proximity to the substrate in a plasma chamber. The edge protection plate overlaps edges and/or sides on the substrate to provide protection to reflective coatings on the edge, sides, and back of the substrate.

Abstract: Embodiments described herein provide apparatus and methods of etching a substrate using an ion etch chamber having a movable aperture. The ion etch chamber has a chamber body enclosing a processing region, a substrate support disposed in the processing region and having a substrate receiving surface, a plasma source disposed at a wall of the chamber body facing the substrate receiving surface, an ion-radical shield disposed between the plasma source and the substrate receiving surface, and a movable aperture member between the ion-radical shield and the substrate receiving surface. The movable aperture member is actuated by a lift assembly comprising a lift ring and lift supports from the lift ring to the aperture member. The ion-radical shield is supported by shield supports disposed through the aperture member. The aperture size, shape, and/or central axis location may be changed using inserts.

Abstract: An electronic device comprises an in-plane component formed in an organic semiconductor layer, desirably graphene, on a flexible substrate. The component is formed using imprint lithography to create a trench through the organic semiconductor layer in a roll-to-roll process. The number of process steps required is limited to allow manufacture of the device in a single integrated apparatus.

Abstract: An assembly for selectively etching an inkjet printhead includes a substrate and printhead layers formed on the substrate. A bonding region can provide a location on the printhead layers for an electrical bond. An ink channeling region can be defined at least in part by the printhead layers. A mask layer can partially cover the printhead layers and include a first opening positioned over the bonding region and a second opening positioned over the ink channeling region. The assembly can also include a via at the first opening and a trench at the second opening having greater depth than the via.

Abstract: A method for forming holes in the backside dielectric layer of solar cells for fabrication of rear point contact. The backside dielectric layer is coated with a layer of carbon. A shadow mask is placed over the carbon layer and reactive ion etch (RIE) is used to transfer the holes in the shadow mask to the carbon layer, to thereby form a carbon mask. The shadow mask is then removed and RIE is used to transfer the holes from the carbon mask to the dielectric layer. The carbon mask is then removed by, e.g., ashing.

Abstract: A method of cleaning a bevel edge of a substrate in an etch processing chamber is provided. The method includes placing a substrate on a substrate support in a processing chamber. The method also includes flowing a cleaning gas through a gas feed located near a center of a gas distribution plate, disposed at a distance from the substrate support. The method further includes generating a cleaning plasma near a bevel edge of the substrate to clean the bevel edge by powering a bottom edge electrode or a top edge electrode with a RF power source and grounding the edge electrode that is not powered by the RF power source, the bottom edge electrode surrounds the substrate support and the top edge electrode surrounds the gas distribution plate.

Abstract: Plasma processing chambers having internal Faraday shields with defined groove configurations, are defined. In one example, the chamber includes an electrostatic chuck for receiving a substrate and a dielectric window connected to a top portion of the chamber, where the dielectric window disposed over the electrostatic chuck. Also included is a Faraday shield disposed inside of the chamber and defined between the electrostatic chuck and the dielectric window. The Faraday shield includes an inner zone having an inner radius range, a middle zone having a middle radius range, an outer zone having an outer radius range, where the inner zone is adjacent to the middle zone, and the middle zone being adjacent to the outer zone.

Abstract: A passing apparatus includes: upper and lower sealing rolls dealing with variations in a thickness of a proceeding strip, the upper and lower sealing rolls allowing the strip to pass; and a strip sealing unit dealing with variations in a width of the proceeding strip, the strip sealing unit cooperating with the upper and lower sealing rolls to seal the proceeding strip passing through a chamber in a state in which the strip sealing unit surrounds the proceeding strip.

Abstract: Methods of forming arrays of small, densely spaced holes or pillars for use in integrated circuits are disclosed. Various pattern transfer and etching steps can be used, in combination with pitch-reduction techniques, to create densely-packed features. Conventional photolithography steps can be used in combination with pitch-reduction techniques to form superimposed patterns of crossing elongate features with pillars at the intersections. Spacers are simultaneously applied to sidewalls of both sets of crossing lines to produce a pitch-doubled grid pattern. The pillars facilitate rows of spacers bridging columns of spacers.

Abstract: According to an embodiment, a plasma treatment apparatus includes a processing target holding unit and a plasma generation unit in a chamber. The processing target holding unit includes a supporting table on which a wafer is mounted, a ring-shaped insulator ring arranged at an outer periphery of the supporting table, and a protective film containing yttria for covering a side surface section and an upper surface section of the insulator ring. The protective film is formed thicker on the upper surface section than on the side surface section of the insulator ring.