Abstract: A preferred embodiment of the present invention comprises a vitreous quartz pipe or container having a connector including a flange formed from at least one strip or rod-shaped piece of transparent quartz glass which is wound circumferentially around either an inner or outer surface of a portion of the pipe or container and secured to the pipe or container to thereby form a closed-ring flange. The portion of the pipe or container having the attached flange may be an open end of the pipe or container or may be a wall portion where a connector for mounting to fixtures or other fittings may be desired. This type of strip or rod-shaped piece of quartz glass can be made via a conventional pulling technique such that a strip or rod having the appropriate uniform cross-sectional shape is obtained. The prepared strips or rod-shaped pieces are then easily cut with a saw device to appropriate lengths.

Abstract: A method of preparing a high purity massive synthetic silica glass article. The method includes a homogenizing step, wherein a rod shaped synthetic silica glass material has a greater optical homogeneity in a plane perpendicular to its rotational axis than a plane parallel thereto, a step of forming the homogeneous synthetic silica glass and a step of cutting the formed synthetic silica glass.

Abstract: Provided are an outer-diameter blade, an inner-diameter blade and cutting machines using both blades for cutting hard material, and a core drill and a core-drill processing machine for forming a hole into hard material, whereby the mechanical processing with reduction in the cutting and/or contact resistance to the tools is realized, so that in the case of the outer-diamond blade, it is prevented from occurring that a to-be-cut object is warped and put into contact to the blade to cause chipping; in the case of the inner-diameter blade, it is prevented from occurring that the blade is bowed and/or a cutting surface is curved; and in the case of the core drill, not only are grinding powder of a workpiece and loosed-off abrasive grains effectively removed to prevent those from being loaded between the drill and the workpiece, but neither of cracking and chipping occur when the drill passes through the workpiece.

Abstract: An object of the present invention is to provide a synthetic silica glass optical material which exhibits excellent transmittance as well as durability for high output power vacuum ultraviolet rays, being emitted from, for example, ArF excimer lasers and Xe.sub.2 excimer lamps, and to provide a method for producing the same. A synthetic silica glass optical material for high output power vacuum ultraviolet rays made from ultra high purity synthetic silica glass for use in the wavelength region of from 165 to 195 nm, containing OH groups at a concentration of from 5 to 300 wtppm with a fluctuation width in OH group concentration (.DELTA.OH/cm) of 10 wtppm or less, containing hydrogen molecules at a concentration of from 1.times.10.sup.17 to 1.times.10.sup.19 molecule/cm.sup.3 with a fluctuation width in hydrogen molecule concentration (.DELTA.H.sub.2 /cm) of 1.times.10.sup.17 molecule/cm.sup.3 or lower, and containing chlorine at a concentration of 50 wtppm or lower.

Abstract: A crucible with 22 inches or more in inner diameter, which has a small deformation of the body under exposure to abundant heat radiation during pulling a single crystal, and which has no practical problem, and a method of producing the same are disclosed.

Abstract: A method for producing an improved quartz glass crucible for pulling up silicon single crystals comprises forming a premolding by feeding powdered silicon dioxide into the mold and by then forming it into a layer along the inner surface of the mold; forming a crucible base body of a translucent quartz layer by heating the premolding from the inner side, thereby partially melting the powdered silicon dioxide, followed by cooling and solidifying the melt; forming a crystallization-promoter containing layer along the internal wall surface of the crucible body by scattering the crystallization promoter on the surface of the internal wall of the crucible body during or after forming the crucible base body; and forming a synthetic quartz glass inner layer by scattering and fusing a powder of silicon dioxide on the crystallization promoter-containing layer that is formed along the internal wall surface of the crucible base body.

Abstract: An excellent quartz glass optical member having stable laser beam resistance, can be obtained by preparing quartz glass in a process having:a first step of subjecting a starting material obtained from silicon halide, alkoxysilane, alkylalkoxysilane, etc. to an oxidizing heat treatment in a temperature range between 600 and 1,500.degree. C., to decrease the hydrogen concentration to 5.times.10.sup.16 molecules/cm.sup.3 or less and at the same time eliminate reducing defects;a second step of subsequently holding the quartz in a hydrogen-containing atmosphere in a temperature range between 200 and 600.degree. C., to establish a hydrogen concentration in the glass of 1.times.10.sup.17 molecules/cm.sup.3 ; anda third step of carrying out a treatment of making the hydrogen concentration of the resultant quartz glass uniform in an atmosphere of air, inert gas, hydrogen, a mixture of hydrogen and inert gas, or a mixture of air and inert gas in a temperature range between 300 and 800.degree. C.

Abstract: A known projection aligner for integrated circuit fabrication, in which an integrated circuit pattern image is projected on a wafer, comprises an ArF excimer laser and an optical system composed of groups of quartz glass optical members made of synthetic quartz glass. To provide a projection aligner having optical properties, such as durability, optical transmittance and the like, which are not degraded over a long time of operation and the optical system can be constructed at a low cost as a whole, it is suggested that the optical system comprises a first quartz glass optical member group whose hydrogen molecule concentration is in the range between 1.times.10.sup.17 and 5.times.10.sup.18 molecules/cm.sup.3 and a third quartz glass optical member group whose hydrogen molecule concentration is in the range between 5.times.10.sup.18 to 5.times.10.sup.19 molecules/cm.sup.3.

Abstract: A large diameter quartz crucible with an inner diameter of 22 inches or more comprises an opaque silica glass outer layer having bubbles of 10 .mu.m to 250 .mu.m in diameter and 5 mm to 20 mm in thickness and a transparent silica glass inner layer having 0.5% or less in a bubble content and 0.3 mm or more in thickness which is molten and integrated with an inner surface of the outer layer. The outer layer has an OH group concentration of 80 ppm or less and the gas pressure in a bubble in the outer layer is lower than atmospheric pressure so that a volume expansion ratio of the bubble is minimized when being heated in condition of pulling a single crystal.

Abstract: Opaque silica glass having a density of 2.0 to 2.18 g/cm.sup.3, sodium and potassium elements concentrations in the silica glass of each 0.5 ppm or less and an OH group concentration of 30 ppm or less, and containing bubbles which are independent bubbles having the following physical values: a bubble diameter of 300 .mu.m or less, and a bubble density of 100,000 to 1,000,000 bubbles/cm.sup.3, and a production process for opaque silica glass, including: filling quartz raw material grain having a particle size of 10 to 350 .mu.m in a heat resistant mold, heating it in a non-oxidizing atmosphere from a room temperature up to a temperature lower by 50 to 150.degree. C. than a temperature at which the above raw material grain is melted at a temperature-raising speed not exceeding 50.degree. C./minute, then, slowly heating it up to a temperature higher by 10 to 80.degree. C. than the temperature at which the quartz raw material grain is melted at the speed of 10.degree. C.

Abstract: A method of preparing a ball-shaped synthetic silica glass optical article. The method includes a step of providing a rod-shaped synthetic silica glass having end faces at both sides thereof and having fewer cords per unit volume viewed in a direction perpendicular to a line connecting the end faces relative to the number of cords per unit volume viewed in a direction along the line connecting the end faces. The synthetic silica glass being optically homogeneous in the direction perpendicular to the line connecting the end faces. The method includes the further step of establishing support portions at the end faces of the synthetic silica glass. The rod-shaped synthetic silica glass is thereupon heated while being rotated around an axis connecting the support portions wherein a molten zone is formed.

Abstract: Provided are high-purity quartz glass having a high purity, in particular, with little zirconium (Zr) and manufactured at low costs from natural quartz as the starting material and a method for the preparation thereof.

Abstract: Quartz powder is fed into a rotating mold to form a crucible-like quartz powder layer body with the help of centrifugal force in the mold. The layer is melted by heating through the inner surface with an arc discharge to manufacture an outer crucible member. A hollow cylindrical inner crucible member having a beveled lower edge is welded to the outer crucible member while a temperature of the inner surface portion of the outer crucible member remains at 1400.degree. C. or higher by a remaining heat.

Abstract: A preferred embodiment of the present invention comprises a vitreous quartz pipe or container having a connector including a flange formed from at least one strip or rod-shaped piece of transparent quartz glass which is wound circumferentially around either an inner or outer surface of a portion of the pipe or container and secured to the pipe or container to thereby form a closed-ring flange. The portion of the pipe or container having the attached flange may be an open end of the pipe or container or may be a wall portion where a connector for mounting to fixtures or other fittings may be desired. This type of strip or rod-shaped piece of quartz glass can be made via a conventional pulling technique such that a strip or rod having the appropriate uniform cross-sectional shape is obtained. The prepared strips or rod-shaped pieces are then easily cut with a saw device to appropriate lengths.

Abstract: An analytical method for the quantitative determination of the impurities in silicon dioxide by which trace amounts of hardly soluble impurities contained in silicon dioxide can be reliably decomposed and converted into a solution so that the contents of all of the impurities contained in silicon dioxide or, in particular, zirconium in a natural quartz powder can be accurately determined. Silicon dioxide is decomposed with hydrofluoric acid or an acid mixture of hydrofluoric acid and another inorganic acid to give a decomposition solution which is, as such or after admixture with another inorganic acid, subjected to evaporation to dryness and the residue is heated to cause fusion with addition of a salt or hydroxide of an alkali metal followed by dissolution of the salt or hydroxide of an alkali metal with pure water or with an aqueous solution of an inorganic acid to give an aqueous solution which is subjected to quantitative analysis of the impurities therein.

Abstract: A high purity ball-shaped optical article formed of silica glass useful in optical systems employed in photolithography applications. The optical article is characterized by end faces and a side face positioned between the end faces. The side face is externally projected beyond the outline of the end faces and has a spherical configuration. The optical article is uniquely characterized by a smaller number of cords per unit area, viewed in a direction perpendicular to a line connecting the end faces, than the number of cords per unit area viewed in a direction along the line connecting the end faces. The article is also defined by optical homogeneity in a direction perpendicular to the line connecting the end faces.

Abstract: A method for fabricating a large-sized primary treated quartz glass tube by perforating a cylindrical quartz glass mother material by a hot carbon drill press-in-process followed by etching and washing. The large-sized primary treated quartz glass tube is converted to a large-sized quartz glass preform by combining it with a core glass rod for an optical fiber. Another embodiment is a method for fabricating a large-sized quartz glass tube by heating, hot drawing or hot drawing under pressure using a tool-free drawing method under control of an inside pressure of the large-sized primary treated quartz glass tube at a temperature ranging from 1600.degree. C. to 3000.degree. C. to satisfy a specific equation.

Abstract: A process for producing opaque silica glass in which a quartz raw material grain having a particle size of 10 to 350 .mu.m is filled into a heat resistant mold, the quartz raw material grain is heated in a non-oxidizing atmosphere from a room temperature up to a temperature lower by 50.degree. to 150.degree. C. than a temperature at which the above raw material grain is melted at a temperature-increase speed not exceeding 50.degree. C./minute, then, slowly heated up to a temperature higher by 10.degree. to 80.degree. C. than the temperature at which the quartz raw material grain is melted at the speed of 10.degree. C./minute or less, and the heated quartz raw material grain is further maintained at the temperature higher by 10.degree. to 80.degree. C. than the temperature at which the quartz raw material grain is melted, followed by cooling down to the room temperature.

Abstract: An improved method is proposed for the preparation of a semiconductor silicon single crystal of N-type by the Czochralski process, which is free from the problem of occurrence of delayed OSFs as defects in the single crystal even after prolonged storage at room temperature based on the discovery that presence of a certain amount of aluminum in the melt of silicon contained in a fused silica glass crucible acts to suppress occurrence of delayed OSFs as a type of defects in the single crystal while copper as an impurity acts adversely in this regard. With a known fact that an about 30 .mu.m thick inner surface layer of the crucible is melted down into the silicon melt during the single crystal pulling-up process, namely, the invention proposes use of a crucible of which the inner surface layer of 30 .mu.m thickness contains aluminum in an average concentration of 40 to 500 ppm by weight while the content of copper is as low as possible not to exceed 0.5 ppb by weight.

Abstract: The present invention provides large, high-purity quartz glass plate with a high degree of smoothness and flatness, its manufacturing method and equipment. The invention is characterized by the procedure in which a quartz glass tube with an opening over a specific width, in the direction of the tube shaft, that is preferably band-shaped, is heated and softened in a band-shaped area over the entire width, in the direction of the tube shaft, progressing sequentially along the direction of tube circumference from a specific position on the glass tube. While softening and heating, the quartz glass tube is pulled in a line approximately tangential to the specific position to flatten the glass tube.