Abstract: A quartz glass crucible which has a non-transparent outer layer formed through melting a natural silica powder and a transparent layer formed in the inside of the outer layer, wherein the transparent layer comprises a natural quartz layer having a thickness of 0.4 to 5.0 mm transparent layer comprising a synthetic quarts glass is formed thereon in the inside of the crucible in the range of 0.15 to 0.55 L relative to L, which is the distance from the center of the bottom of the inner surface of the quartz glass crucible to the upper end thereof along the inner surface thereof. The quartz glass crucible can be suitably used for suppressing the occurrence of vibration and reducing the generation of roughened face in the surface of a crucible, and thus for pulling up a silicon single crystal with enhanced stability.

Abstract: A mandrel for producing quartz glass, comprising at least two columnar or cylindrical, carbon fiberreinforced carbon composite material made members joined in series by screw thread parts. The mandrel is carbonimpregnated and/or carbon-coated on the screw thread parts, and, in addition, may be provided with reinforcing members on the outer sides of the screw thread parts. Quartz glass fine particles obtained by flame-hydrolyzing a volatile silicon compound are deposited, using this mandrel, on the surface of a heat-resisting substratum or on a starting rod at the end of the mandrel to easily form a large porous quartz glass mother material, the porous quartz glass mother material is dehydrated and transparently vitrified to produce a large optical fiber mother material, and further the optical fiber mother material is drawn to produce a low-cost, high-precision optical fiber.

Abstract: An object of the present invention is to provide a polishing method for producing, in a relatively short period of time, a tubular brittle material having an inner surface of high surface precision with a maximum roughness Rmax of 0.1 ?m or smaller and a center line average roughness Ra of 0.01 ?m or smaller, and to provide a tubular brittle material with high precision using said polishing method. The polishing method according to the invention is characterized by that the inner surface of the tubular material being pre-cut into a tubular shape using a honing machine is further polished with a sheet material having diamond abrasives attached thereon. Also claimed is a tubular brittle material obtained by said polishing method.

Abstract: An object is to provide a method for producing an optical synthetic quartz glass and an optical synthetic glass, having a birefringence of lower than 0.5 nm/cm and having favorable refractive index distribution, yet without lowering the productivity, as well as to provide an annealing furnace suitably used in practicing said method. In a step of raising the temperature of a columnar optical synthetic quartz glass preform to a temperature of from 800° C. to 1200° C., and after keeping for a definite time, lowering the temperature, the temperature is lowered with a temperature difference of from 1 to 20° C. between the temperature of the light transmitting surface of the optical synthetic quartz glass preform and the temperature of the outer peripheral side surface of the optical synthetic quartz glass preform at temperature-lowering rates of from 2 to 50° C./hour, respectively.

Abstract: An object of the present invention is to overcome the problems of the prior art technique, and to provide a heat treatment method as well as a heat treatment apparatus capable of heat treating, with higher efficiency, a synthetic quartz glass for optical use having higher homogeneity and higher purity. Another object of the present invention is to provide and a synthetic quartz glass for optical use.

Abstract: The present invention provides a quartz glass single hole nozzle for feeding fluid capable of performing high-precision control of a flow rate, a burner for heat processing equipped with the quartz glass single hole nozzle, a quartz glass multihole burner head for feeding fluid preferably used in flame processing or the like, and a quartz glass burner for heat processing equipped with the multihole burner. By using the nozzle, even if a distal end portion of the quartz glass burner, namely the nozzle is broken by contact with a workpiece or the like, it is enough to only replace the broken nozzle with a new one without a necessity for replacing the entire expensive quartz glass burner. When applying the nozzle to a metal burner, there can be given usefulness of the quartz glass such as heat resistance and contamination resistance or the like.

Abstract: It is an object of the present invention to provide a hydrogen-doped silica powder that is useful in the formation of a quartz glass crucible that is capable of pulling a silicon single crystal without causing a state having dislocations in the silicon single crystal due to peeling of quartz glass segment. It is a further object of the invention to provide a quartz glass crucible for use in pulling a silicon single crystal whose inner surface is formed by use of the hydrogen-doped silica powder and a producing method of the silica powder.

Abstract: It is an object of the present invention to provide a glass member resistant against plasma corrosion suitably used as a jig material in producing semiconductors, which exhibits excellent resistance against plasma corrosion, and which is free from the generation of particles. The above problem is solved by a glass member resistant to plasma corrosion, comprising a portion to be exposed to plasma gas, which is made of a glass material containing, as the essential component, one compound component selected from the group consisting of compounds expressed by one of the chemical formulae SiO2—Al2O3—CaO, SiO2—Al2O3—MgO, SiO2—BaO—CaO, SiO2—ZrO2—CaO, SiO2—TiO2—BaO, provided that the constitution ratio of the compound components is within the vitrification range.

Abstract: An object of the invention is to provide a quartz glass crucible for pulling up silicon single crystal and a method for producing the same, suitable for improving the productivity of the crucible and the quality of the silicon single crystal, which, by forming a crystalline layer on the inner surface of the quartz glass crucible during pulling up silicon single crystal, prevents degradation from occurring on the inner surface of the crucible and increases the ratio of single crystal while preventing the dislocation from forming on the single crystals.

Abstract: Problems the invention is to solve: An object of the present invention is to provide a method for producing a quartz glass crucible capable of pulling up a silicon single crystal at a highly improved yield, yet without generating oscillation at the surface of the melt on pulling up silicon single crystal, and free from generating dislocations due to the peeling off of quartz glass fractions.

Abstract: An object of the present invention is to provide a quartz glass body, especially a quartz glass jig for plasma reaction in producing semiconductors having excellent resistance against plasma corrosion, particularly, excellent corrosion resistance against F-based gaseous plasma; and a method for producing the same. A body made of quartz glass containing a metallic element and having an improved resistance against plasma corrosion is provided that contains bubbles and crystalline phase at an amount expressed by projected area of less than 100 mm2 per 100 cm3.

Abstract: An object of the present invention is to provide a quartz glass jig, which, when employed in a processing apparatus using plasma, is less in generation of abnormal etching and particles and low in contamination with impurities. This object is obtained by a quartz glass jig for a processing apparatus using plasma, wherein a surface of the jig is subjected to grinding or a sandblast processing and has a surface roughness Ra in the range of from 2 ?m to 0.05 ?m, and microcracks of grinding marks formed during the grinding or sandblast processing have a depth of 50 ?m or less.

Abstract: The granule consists of individual granules approximately spherical in shape, having a pore volume of 0.5 cm3, a mean diameter of pores of 50 nm or less, a specific surface area of 100 m2/g or less, and a bulk density of 0.7 g/cm3 or higher. It is produced by dispersing a fumed silica obtained by hydrolysis of a silicon compound into pure water to obtain a slurry, and drying the slurry. The granule is used for producing high purity synthetic quartz glass powder. The method further comprises: a first heat treatment under an oxygen-containing atmosphere, a second heat treatment in a temperature range of from 600 to 1100° C., and a third heat treatment in a temperature range of from 1100 to 1300° C. under an atmosphere containing hydrogen chloride; and a step of densification comprising calcining the product at a temperature not higher than 1500° C. under vacuum or in an atmosphere of gaseous hydrogen or gaseous helium.

Abstract: The invention provides a method for producing a quartz glass jig for use in semiconductor industries, which enables increasing the surface layer cleanliness simply and surely at low cost; it also provides a quartz glass jig improved in surface layer cleanliness. The inventive means for resolution are a method comprising processing a quartz glass raw material into a desired shape by a treatment inclusive of fire working, annealing for stress removal, and cleaning treatment to obtain the final product, the method is characterized by that it comprises performing gas phase etching step and gas phase purification step on the surface layer of the quartz glass jig after applying the annealing treatment for stress removal but before the cleaning treatment, wherein the gas phase purification step is carried out continuously after the gas phase etching step.

Abstract: In the light of the disadvantages of the prior art technology, an object of the present invention is to provide a method for producing a synthetic quartz glass member for excimer lasers, which comprises, while suppressing the generation of reductive defects which impairs the resistance against laser radiations, incorporating a sufficient amount of hydrogen molecules capable of achieving a high resistance against laser radiation into the quartz glass, yet uniformly incorporating the hydrogen molecules to realize a flat distribution in refractive indices attributed to the distribution in the density of hydrogen molecules. It is also an object of the present invention to provide a synthetic quartz glass member for excimer lasers obtained by the production method above, which yields high resistance against laser radiations and homogeneity.

Abstract: Provided are a quartz glass crucible for pulling up a silicon single crystal, with which not only a defectless silicon single crystal can be pulled but a single crystallization ratio can greatly be improved and a production method therefor. The quartz glass crucible comprises a crucible body constituted of a semi-transparent quartz glass layer and a transparent quartz glass layer formed on the inner wall surface of the crucible bass body and no expanded bubbles equal to ro more than 0.5 mm in diameter are present in a layer 1 mm in depth from an inner surface of the quartz glass crucible after the silicon single crystal is pulled up using the quartz glass crucible.

Abstract: In a vertical type wafer supporting jig, a ring-like support plate is fixed to support pillars by a simple structure without conventional welding and without risk of the ring-like support plate falling off. The vertical type wafer supporting jig is configured for mounting many wafers onto many support plates stacked in a vertical direction and fixed to support pillars with a predetermined wafer mounting interval between the support plates. Support groove portions into which the support plates are inserted and supported are formed in the support pillars with a predetermined interval in the vertical direction between them. A fixing rod is provided adjoining at least one of the support pillars.

Abstract: A cylindrical, chlorine-free synthetic quartz glass blank of a specific size obtained by homogenizing a synthetic quartz glass ingot having periodic striae along a direction of growth has (a) striae grades in the working and off-axis directions which meet grade A of U.S. military specification MIL-G-174B, (b) average hydroxyl group concentrations in the working and off-axis directions of 700 to 1,000 ppm each, (c) average fictive temperatures in the working and off-axis directions of 850 to 950° C. each, and (d) a refractive index distribution for 633 nm wavelength light in the working direction of at most 1×10−6. The blank has a good transmittance to laser light, undergoes little deterioration when irradiated with laser light, and is particularly suitable for ArF excimer laser-related applications.

Abstract: An object of the present invention is to provide a synthetic quartz glass optical material having a high optical transmittance for a radiation 157 nm in wavelength emitted from F2 excimer laser and a high resistance against irradiation of a F2 excimer laser radiation, yet having a uniformity suitable for such a fine patterning using a F2 excimer laser, and to provide an optical member using the same. The problems above are solved by a synthetic quartz glass optical material for F2 excimer lasers having an OH group concentration of 0.5 ppm or lower, a fluorine concentration of 0.1 to 2 mol %, a hydrogen molecule concentration of 5×1016 molecules/cm3 or lower, a difference between the maximum and minimum fluorine concentrations within 20 mol ppm, and a difference between the maximum and minimum refraction indices of 2×10−5 or lower.

Abstract: It is an object of the present invention to provide a quartz glass jig excellent in the plasma etching resistant characteristics, which does not generate an abnormal etching and particles when used for a plasma generating apparatus. The above Object is obtained by a plasma resistant quartz glass jig that is used for an apparatus of generating plasma, wherein the surface roughness Ra of the quartz glass surface is in a range of from 5 &mgr;m to 0.05 &mgr;m, the number of microcracks of the surface is not more than 500 microcracks/cm2, and the hydrogen molecule concentration in the quartz glass is at least 5×1016 molecules/cm3.