Abstract: The disclosed is a method of manufacturing a silica glass crucible for pulling silicon single crystals. In the method, reduced pressure is imparted from the inner surface to the outer surface of a crucible-shaped molded product and the crucible-shaped molded product is arc-fused while rotating the same to form a silica glass crucible with a transparent layer on the inner surface side and a bubble layer on the outer surface side. The inner surface of the wall portion of the silica glass crucible is fused a second time by arc fusion to cause bubbles present in the transparent layer of the inner surface of the wall portion to be displaced toward the bottom portion of the inner surface of the wall portion. The inner surface of the bottom portion of the silica glass crucible is fuse a second time by arc fusion to cause bubbles present in the transparent layer of the inner surface of the bottom portion to be displaced toward the periphery of the inner surface of the bottom portion.

Abstract: Provided is a vitreous silica crucible which can suppress inward sagging and buckling of the sidewall effectively even when time for pulling silicon ingots is extremely long. According to the present invention, provided is a vitreous silica crucible for pulling a silicon single crystal, wherein the crucible has a wall comprising, from an inner surface toward an outer surface of the crucible, a transparent vitreous silica layer having a bubble content rate of less than 0.5%, a bubble-containing vitreous silica layer having a bubble content rate of 1% or more and less than 50%, a semi-transparent vitreous silica layer having a bubble content rate of 0.5% or more and less than 1.0% and having an OH group concentration of 35 ppm or more and less than 300 ppm.

Abstract: A fused silica article having a combined concentration of hydroxyl (OH) and deuteroxyl (OD) concentration of less than 10 parts per million (ppm) and, in one embodiment, less than 1 ppm. The fused silica article is formed by drying a soot blank in a halogen-free atmosphere comprising carbon monoxide. The dried soot blank may optionally be doped to reach target levels of OH and OD concentrations and improve homogeneity within the fused silica article. The dried soot blank is then oxidized and, sintered to form the article. A method of reducing the combined concentration of OH and OD to less than 10 ppm is also described.

Abstract: The invention starts from a known component of quartz glass for use in semiconductor manufacture, which component at least in a near-surface region shows a co-doping of a first dopant and of a second oxidic dopant, said second dopant containing one or more rare-earth metals in a concentration of 0.1-3% by wt. each (based on the total mass of SiO2 and dopant). Starting from this, to provide a quartz glass component for use in semiconductor manufacture in an environment with etching action, which component is distinguished by both high purity and high resistance to dry etching and avoids known drawbacks caused by co-doping with aluminum oxide, it is suggested according to the invention that the first dopant should be nitrogen and that the mean content of metastable hydroxyl groups of the quartz glass is less than 30 wtppm.

Abstract: A fused silica glass and a fused silica article having a combined concentration of at least one of OH and OD of up to about 50 ppm. The fused silica glass is formed by drying a fused silica soot blank or preform in an inert atmosphere containing a drying agent, followed by removal of residual drying agent from the dried soot blank by heating the dried soot blank in an atmosphere comprising an inert gas and of oxygen.

Abstract: Disclosed are methods for hydrogen loading silica glass and silica glass comprising loaded H2. The methods can lead to H2 gradient in the glass material. Alternatively, the method may involve the use of varying H2 partial pressure of H2 in the atmosphere. Both can result in expedited hydrogen loading process.

Abstract: An object of the invention is to provide a process for producing a synthetic quartz glass while taking account of a refractive index distribution remaining in the synthetic quartz glass; a jig for use in the synthetic-quartz-glass production process; and a synthetic quartz glass for an optical member, produced by the process.

Abstract: The present invention relates to a quartz glass blank for an optical component for transmitting radiation of a wavelength of 15 nm and shorter, the blank consisting of highly pure quartz glass, doped with titanium and/or fluorine, which is distinguished by an extremely high homogeneity. The homogeneity relates to the following features: a) micro-inhomogeneities caused by a local variance of the TiO2 distribution (<0.05% TiO2, averaged over a volume element of (5 ?m)3 in relation to the mean value of the TiO2 content), b) an absolute maximum inhomogeneity in the thermal expansion coefficient ?? in the main functional direction (<5 ppb/K), c) a radial variance of the thermal expansion coefficient over the usable surface of the quartz glass blank of not more than 0.4 ppb/(K.cm); d) a maximum stress birefringence (SDB) at 633 nm in the main functional direction of 2 nm/cm with a specific progression; and e) a specific progression of the ??, averaged according to (b) on the optical surface.

Abstract: The present disclosure relates to a silica-based crucible material that includes, before sintering or firing, selected amounts of a thermal expansion stabilizer component (B2O3 and Ca2SiO4) which impart improved thermal shock resistance and enhanced ability to withstand repeated thermal cycling, to a sintered or fired crucible made of the material. An illustrative embodiment of the invention provides a crucible material whose chemical composition comprises, in weight %, about 91% to about 98% SiO2, about 1% to about 8% thermal stabilizer component, and up to about 1.0% of additional oxides including MgO, Al2O3 Fe2O3, CaO and ZrO2.

Abstract: In a known method for bonding components made of material with a high silicic acid content by means of a substance to substance bond, a SiO2-containing bonding mass is formed between connecting surfaces of the components. In order to provide for cost-efficient manufacture of a thermally stable composite, the invention proposes to generate a SiO2-containing bonding mass that is generic with regard to the material with a high silicic acid content, comprising the following procedural steps: provision of a slurry containing amorphous SiO2 particles; formation of a slurry mass between the connecting surfaces which are fixed in position with regard to each other; drying of the slurry mass; and solidification of the slurry mass by heating under formation of the SiO2-containing bonding mass. A component assembly manufactured according to the method of the invention shows high temperature resistance and thermal fatigue resistance and can also be used in contamination-sensitive applications.

Abstract: Disclosed in the application are a synthetic silica glass having low fluence-dependent transmission, particularly at about 193 nm, and a process for making the same. The glass may desirably exhibit a low level of fluorescence at 290 and 390 nm when activated at about 248 nm. The glass may desirably exhibit low level of LIWFD, [SiH*] and/or [ODC].

Abstract: A reforming process of a quartz glass crucible in which the quartz glass crucible is reformed by an arc discharge generated by electrodes positioned around a rotational axis and configured to heat an inside surface of the crucible while the crucible is rotated. The process includes arranging electrodes in an electrode structure such that neighboring electrodes are positioned at regular intervals in a ring-like configuration; forming a stable ring-like arc between the neighboring electrodes, without generating a continuous arc between electrodes facing each other across a central portion of the ring-like configuration; heating the inside surface of the crucible; and removing a foreign substance located on the inside surface of the crucible or a bubble located under the inside surface of the crucible.

Abstract: A method of constructing a curved optical device includes assembling of at least one cell having opposed flexible substrates with a controlled distance therebetween to form a gap adapted to receive a fluid. The process continues by holding only a portion of the cell in a fixture, positioning a curved mold surface proximal the cell and heating at least one of the curved mold surface and cell. Next, the cell is conformed to the mold surface so that the cell substantially retains the curved shape when the heat and the mold surface are removed.

Abstract: To reduce the change in the refractive index of an irradiated portion of synthetic quartz glass, caused by the irradiation with a high energy light emitted from a light source such as a KrF excimer laser or an ArF excimer laser. A process for producing an optical member made of synthetic quartz glass, wherein the OH group concentration of the optical member is set depending upon the energy density of the laser beam employed, to adjust the ratio R (KJ/cm.sup.2-ppb).sup.-1 of the change in the refractive index of the optical member to the cumulative irradiation energy (KJ/cm.sup.2) by the laser, to be 0.Itoreq.R.Itoreq.0.2, thereby to control the change in the refractive index of the optical member made of synthetic quartz glass by the irradiation with a laser beam to be within a predetermined range.

Abstract: An ideal quartz glass for a wafer jig for use in an environment having an etching effect is distinguished by both high purity and high resistance to dry etching. To indicate a quartz glass that substantially fulfills these requirements, it is suggested according to the invention that the quartz glass is doped with nitrogen at least in a near-surface area, has a mean content of metastable hydroxyl groups of less than 30 wt ppm and that its fictive temperature is below 1250° C. and its viscosity is at least 1013 dPa·s at a temperature of 1200° C. An economic method for producing such a quartz glass comprises the following method steps: melting an SiO2 raw material to obtain a quartz glass blank, the SiO2 raw material or the quartz glass blank being subjected to a dehydration measure, heating the SiO2 raw material or the quartz glass blank to a nitriding temperature in the range between 1050° C. and 1850° C.

Abstract: The disclosed is a method of manufacturing a silica glass crucible for pulling silicon single crystals. In the method, reduced pressure is imparted from the inner surface to the outer surface of a crucible-shaped molded product and the crucible-shaped molded product is arc-fused while rotating the same to form a silica glass crucible with a transparent layer on the inner surface side and a bubble layer on the outer surface side. The inner surface of the wall portion of the silica glass crucible is fused a second time by arc fusion to cause bubbles present in the transparent layer of the inner surface of the wall portion to be displaced toward the bottom portion of the inner surface of the wall portion. The inner surface of the bottom portion of the silica glass crucible is fuse a second time by arc fusion to cause bubbles present in the transparent layer of the inner surface of the bottom portion to be displaced toward the periphery of the inner surface of the bottom portion.

Abstract: The invention relates to a transparent and essentially colorless ?-quartz glass-ceramic material which is free of TiO2, As2O3, Sb2O3 and phosphates; articles formed from said glass-ceramic material; lithium aluminosilicate glasses, precursors for said glass-ceramic material; and methods of producing said glass-ceramic material and said articles formed from said glass-ceramic material.

Abstract: A method of producing a quartz glass crucible for pulling a single crystal comprising: providing a melting mold comprising a wall having passages between outside and inside; providing an outer layer granulation consisting of first coarser SiO2 particles and forming an outer granulation layer from the outer layer granulation on the inside of the melting mold wall; providing a barrier layer granulation consisting of second finer SiO2 particles and forming a barrier granulation layer from the barrier layer granulation on the outer granulation layer; applying a negative pressure to the outside of the melting mold wall; and heating the barrier granulation layer and the outer granulation layer with formation of a quartz glass crucible with transparent inner layer.

Abstract: A glass lampshade comprising a fusion body of crystal grain glass, an upper crystal glass plate, a lower crystal glass plate, and a curing gel layer. The upper crystal glass plate is attached to the lower crystal plate via the curing gel layer. The fusion body of crystal grain glass is attached to the upper crystal glass plate. A method of producing the glass lampshade.

Abstract: A glass structure having sub-micron and nano-size bandgap structures and a method of fabricating the glass structure is provided.

Abstract: Glass, glass compositions, methods of preparing the glass compositions, microfluidic devices that include the glass composition, and methods of fabricating microfluidic devices that include the glass composition are disclosed. The borosilicate glass composition includes silicon dioxide (SiO2) in a range from about 60% to 74% by total composition weight; boric oxide (B2O3) in a range from about 9% to 25% by total composition weight; aluminum oxide (Al2O3) in a range from about 7% to 17% by total composition weight; and at least one alkali oxide in a range from about 2% to 7% by total composition weight. In addition, the borosilicate glass has a coefficient of thermal expansion (CTE) that is in a range between about 30×10?7/° C. and 55×10?7/° C. Furthermore, the borosilicate glass composition resists devitrification upon sintering without the addition of an inhibitor oxide.

Abstract: Disclosed are synthetic silica glass having a low polarization-induced birefringence, process for making the glass and lithography system comprising optical element made of the glass. The silica glass has a polarization-induced birefringence measured at 633 nm of less than about 0.1 nm/cm when subjected to excimer laser pulses at about 193 nm having a fluence of about 40 ?J·cm?2·pulse?1 and a pulse length of about 25 ns for 5×109 pulses.

Abstract: Method for producing a semifinished product from synthetic quartz glass Methods for producing a semifinished product from synthetic quartz glass by plastic deformation of a softened SiO2 mass in a melt mold are known. Starting from this, to avoid fusion defects as much as possible and to obtain semifinished products of quartz glass in a reproducibly high quality, a method is suggested that comprises the following steps: (a) providing a porous SiO2 soot body, (b) zonewise sintering of the SiO2 soot body in the melt mold at a sintering temperature and during a sintering period with formation of a completely sintered transparent quartz glass body, and directly thereafter (c) shaping the sintered quartz glass body by softening in the melt mold with formation of a viscous quartz glass mass which fills the volume of the melt mold entirely or partly, and (d) cooling the quartz glass mass and removing the mass from the melt mold with formation of the semifinished product.

Abstract: A high-purity vitreous silica crucible which has high strength and is used for pulling a large-diameter single-crystal silicon ingot, includes a double laminated structure constituted by an outer layer composed of amorphous silica glass with a bubble content of 1 to 10% and a purity of 99.99% or higher and an inner layer composed of amorphous silica glass with a bubble content of 0.6% or less and a purity of 99.99% or higher, and in the portion between the upper opening end of the high-purity vitreous silica crucible and the ingot-pulling start line of a silicon melt surface in the step of pulling a single-crystal silicon ingot, a portion corresponding to 40 to 100 volume % from the upper opening end of the crucible is in a crystalline structure free from the crystallization promoter.

Abstract: Disclosed is a synthetic silica glass optical material having high resistance to optical damage by ultraviolet radiation in the ultraviolet wavelength range, particularly in the wavelength less than about 250 nm and particularly, exhibiting a low laser induced wavefront distortion; specifically a laser induced wavefront distortion, measured at 633 nm, of between about ?1.0 and 1.0 nm/cm when subjected to 10 billion pulses of a laser operating at approximately 193 nm and at a fluence of approximately 70 ?J/cm2. The synthetic silica glass optical material of the present invention comprises OH concentration levels of less than about 600 ppm, preferably less than 200 ppm, and H2 concentration levels less than about 5.0×1017 molecules/cm3,and preferably less than about 2.0×1017 molecules/cm3.

Abstract: A method of making a glass-ceramic from at least two different metal oxides is disclosed. The method includes providing the two different metal oxides as a glass, heating the glass above the glass transition temperature of the glass to form a coalesced shape; and heating the coalesced shape to a temperature above the crystallization onset temperature of the glass, thereby forming a glass-ceramic comprising at least 1% by volume crystallites, wherein the crystallites have an average size of less than 1 micrometer. The difference between the glass transition temperature and the crystallization onset temperature is at least 25K.

Abstract: A fused silica article having a combined concentration of hydroxyl (OH) and deuteroxyl (OD) concentration of less than 10 parts per million (ppm) and, in one embodiment, less than 1 ppm. The fused silica article is formed by drying a soot blank in a halogen-free atmosphere comprising carbon monoxide. The dried soot blank may optionally be doped to reach target levels of OH and OD concentrations and improve homogeneity within the fused silica article. The dried soot blank is then oxidized and, sintered to form the article. A method of reducing the combined concentration of OH and OD to less than 10 ppm is also described.

Abstract: A fused silica glass having a composition for use in bulk IR optical applications. The fused silica glass has a OH concentration of less than 5 ppm (parts per million) by weight and an absorbance of less than about 50 ppm/cm at a wavelength of about 1.3 ?m. A method of making the fused silica glass is also described.

Abstract: The invention is based on the object of providing armoring that is lightweight and exhibits a denser microstructure that is improved as against ceramic composite materials. To this end, armoring against high dynamic impulsive loads is provided that comprises a composite material having at least two phases, the first phase forming a matrix for the second phase, and the first phase being a glass or a glass ceramic, and the second phase being embedded and distributed in the form of particles and/or fibers in the matrix formed by the material of the first phase.

Abstract: A new class of nanostructured RE-doped SiO2-base materials that display superior fluorescence properties is provided. In particular, high gain combined with a broad and flat spectral band width is observed in material composed of a high fraction of a nano-dispersed metastable silicate phase in a glassy SiO2 matrix, produced by partial devitrification (crystallization) of several glassy Al2O3/Er2O3- and Y2O3/Er2O3-doped SiO2 compositions. Also, a highly deconvoluted spectral emission, with several prominent peaks, is observed in completely devitrified material, consisting of a uniform nano-dispersion of an equilibrium silicate phase in a crystobalite SiO2 matrix. Such enhanced fluorescence properties were observed in heat treated nanopowders prepared by vapor-phase, solgel, rapid solidification, and spray-pyrolysis methods.

Abstract: A process for preparing foamed glass granulate comprises the following steps: provision of an aqueous glass binder slurry containing water at room temperature, a foaming agent and a glass binder in a preparation tank, addition of glass powder, preferably old glass powder, to the glass binder slurry to form a moist stirrable glass preparation, homogenisation of the glass preparation thus formed, transfer of the glass preparation into a stirring tank, stirring of the glass preparation for a stirring period of between 2 and 6 hours to fuse the glass components at least in part, addition of further glass powder to the glass preparation in a granulation mixer to form granulate green bodies, drying of the granulate green bodies and foaming of the granulate green bodies into foamed glass granulate particles.

Abstract: A mixed quartz powder contains quartz powder and two or more types of doping element in an amount of from 0.1 to 20 mass %. The aforementioned doped elements include a first dope element selected from the group consisting of N, C and F, and a second dope element selected from the group consisting of Mg, Ca, Sr, Ba, Sc, Y, Ti, Zr, Hf, the lanthanides and the actinides. The “quartz powder” is a powder of crystalline quartz or it is a powder of glassy SiO2 particles. It is made form natural occurring quartz or it is fabricated synthetically. The “quartz powder” may be doped. The compounding ratio of the total amount (M1) of the aforementioned first elements and the total amount (M2) of the aforementioned second elements as the ratio of the number of atoms (M1)/(M2) is preferably from 0.1 to 20. Al as well as the aforementioned doped elements is preferably included in a mixed quartz powder of this invention.

Abstract: An F-doped silica glass, a process for making the glass, an optical member comprising the glass, and an optical system comprising such optical member. The glass material comprises 0.1-5000 ppm by weight of fluorine. The glass material according to certain embodiments of the present invention has low polarization-induced birefringence, low LIWFD and low induced absorption at 193 nm.

Abstract: A method of forming a glass sheet includes obtaining a preform generated from a glass composition and conveying the preform through a channel having a temperature that decreases along a length of the channel to form a glass sheet having a predetermined width and thickness.

Abstract: In a synthetic quartz glass ingot which is produced by vapor phase hydrolyzing or oxidatively decomposing a silica-forming starting compound in an oxyhydrogen flame such that silica growth in a direction occurs at a silica particle deposition and melting face, striae visible when viewed from a direction perpendicular to the silica growth direction are distributed periodically over the silica growth direction. The ingot can be used in the production of optical-grade high-homogeneity synthetic quartz glass elements for excimer laser applications, particularly ArF excimer laser applications, in the production of laser damage-resistant optical elements used with light sources such as excimer lasers, and in the production of UV optical fiber.

Abstract: Disclosed herein are a self-foamed porous ceramic composition and a method for making a porous ceramic using the self-foamed porous ceramic composition. The self-foamed porous ceramic is obtained by fabricating a glass consisting of 41˜47 mole % of calcium oxide (CaO), 41˜47 mole % of silica (SiO2) and 6˜18 mole % of borate (B2O3), pulverizing the glass into a finely-divided glass powder having an average particle size of 1˜10 ?m, molding the glass powder, and sintering the molded glass powder.

Abstract: Fluorine-containing synthetic quartz glass is produced by feeding silica-forming material, hydrogen, and oxygen gases from a burner to a reaction zone, flame hydrolyzing the silica-forming material in the reaction zone to form particles of silica, depositing the silica particles on a rotatable substrate in the reaction zone to form a porous silica matrix, and heating and vitrifying the porous silica matrix in a fluorine compound gas-containing atmosphere. During formation of the porous silica matrix, the angle between the center axes of the silica matrix and the silica-forming reactant flame from the burner is adjusted to 90–120° so that the porous silica matrix has a density of 0.1–1.0 g/cm3 with a narrow distribution within 0.1 g/cm3. The resulting quartz glass has a high transmittance to light in the vacuum ultraviolet region below 200 nm.

Abstract: The present invention relates to a quartz glass blank for an optical component for transmission of ultraviolet radiation of a wavelength of 250 nm or shorter, and to a use of the quartz glass blank in microlithography in combination with ultraviolet radiation of a wavelength of 250 nm or shorter. Moreover, the invention relates to a procedure for manufacture of the quartz glass blank. A quartz glass blank of the described type should show little induced absorption and be optimized with respect to compaction and decompaction. The quartz glass blank according to the invention is characterized by the following properties: a glass structure essentially free of oxygen defect sites, an H2-content in the range of 0.1×1016 molecules/cm3 to 4.0×1016 molecules/cm3, an OH-content in the range of 125 wt-ppm to 450 wt-ppm, an SiH group-content of less than 5×1016 molecules/cm3, a refractive index inhomogeneity, ?n, of less than 2 ppm, and a stress birefringence of less than 2 nm/cm.

Abstract: The present invention relates to a quartz glass blank for an optical component for transmission of ultraviolet radiation of a wavelength of 250 nm or shorter, and to a use of the quartz glass blank in microlithography in combination with ultraviolet radiation of a wavelength of 250 nm or shorter. Moreover, the invention relates to a procedure for manufacture of the quartz glass blank. A quartz glass blank of the described type should show little induced absorption and be optimized with respect to compaction and decompaction. The quartz glass blank according to the invention is characterized by the following properties: a glass structure essentially free of oxygen defect sites, an H2-content in the range of 0.1×1016 molecules/cm3 to 4.0×1016 molecules/cm3, an OH-content in the range of 125 wt-ppm to 450 wt-ppm, an SiH group-content of less than 5×1016 molecules/cm3, a refractive index inhomogeneity, ?n, of less than 2 ppm, and a stress birefringence of less than 2 nm/cm.

Abstract: A method for producing ultra-high purity, optical quality, glass articles is disclosed which involves: 1. compacting metaloxide or metalloidoxide to granules having a mean particle size of less than about 1 millimeter; 2. optionally fully sintering the granules to produce high purity, artificial sand; 3. casting the artificial sand by conventional techniques, such as, slip casting, to form a high density, porous, green body; 4. optionally drying and partially sintering the green body; 5. optionally fully sintering the green body under vacuum; and 6. optionally hot isostatic pressing the green body.

Abstract: The invention discloses a method for forming substantially striae-free glass substrates that are suitable for optical applications, including use in forming optical elements or structures such as mirrors and platen stage structures that can be used, for example, in EUV lithography. The method includes forming a mixture of silica soot, binder, lubricant and solvent. The homogenized mixture is then extruded through a slit die or mask into a flat planar pre-form, and the extruded pre-form is then consolidated by heating into a substantially full density, substantially striae-free lithography glass substrate structure. The consolidated perform has a substantially uniform coefficient of thermal expansion and is also substantially void free.

Abstract: The present invention relates to a method for forming an optical device. The method includes providing a glass aggregate. Typically, the glass aggregate is a mixture of fine glass soot particles and coarser ground or milled glass powder. The glass particles are mixed with a liquid to form a slurry which is cast in a mold to form a porous pre-form. Subsequently, the porous pre-form is consolidated into a glass object by heating the pre-form at a relatively high temperature. The method of the present invention produces optical components having substantially no striae. As a result, scattering is substantially reduced when EUV light is reflected from a component produced from the optical blank.

Abstract: Fiber-reinforced ceramic composites contain bundles, tows or hanks of long fibers, wherein the long fiber bundles, tows or hanks are completely surrounded by a short fiber-reinforced matrix, with the long and short fibers having, independently of one another, a mean diameter of from 4 to 12 &mgr;m and the long fibers having a mean length of at least 50 mm and the short fibers having a mean length of not more than 40 mm, a process for producing them and their use for producing clutch disks or brake disks.

Abstract: SiO2—TiO2 glasses having a low coefficient of thermal expansion are produced by a molding being produced that consists of SiO2 powder, SiO2—TiO2 powder or TiO2 powder and that contains by way of secondary component a titanium-containing component which is converted into amorphous TiO2.

Abstract: A method for manufacturing an EUV lithography element mirror includes sagging a plate of a glass material to produce an EUV mirror blank; and polishing a top face of the EUV mirror blank to produce a polished EUV mirror. A method for manufacturing an EUV lithography element mirror includes grinding a top face of a piece of a glass material; sagging a plate of the glass material over the top face of the piece to produce an EUV mirror blank; and polishing a top face of the EUV mirror blank to produce an EUV polished mirror.

Abstract: The present invention provides a simple method for fabricating fiber-optic glass preforms having complex refractive index configurations and/or dopant distributions in a radial direction with a high degree of accuracy and precision. The method teaches bundling together a plurality of glass rods of specific physical, chemical, or optical properties and wherein the rod bundle is fused in a manner that maintains the cross-sectional composition and refractive-index profiles established by the position of the rods.

Abstract: A method and apparatus for the manufacture of synthetic vitreous silica ingots involves the production of a melt of synthetic vitreous silica in a crucible (35) within a refractory furnace (31), and the continuous withdrawal of an ingot (43) through an orifice (40) in the wall of the crucible. The silica may be deposited in the crucible by a synthesis burner (33), which may also serve to maintain the silica above its sintering temperature. The emerging ingot is supported by an arrangement of moveable clamps (44).

Abstract: The invention provides optical projection lithography methods, photolithography photomasks, and optical photolithography mask blanks for use in optical photolithography systems utilizing deep ultraviolet light (DUV) wavelengths below 300 nm, such as DUV projection lithography systems utilizing wavelengths in the 248 nm region and the 193 nm region. The invention provides improved production of lithography patterns by inhibiting polarization mode dispersion of lithography light utilizing low birefringence mask blanks and photomasks.

Abstract: The present invention is a method of making a lithography photomask and photomask blank. The method of making the lithography photomask and photomask blank includes providing a silicon oxyfluoride glass tube having an OH content less than 50 ppm. The method further includes cutting the silicon oxyfluoride glass tube, flattening the silicon oxyfluoride glass tube, and forming the flattened cut silicon oxyfluoride glass tube into a photomask blank having a planar surface. The present invention includes a glass lithography mask preform. The glass lithography mask preform is a longitudinal silicon oxyfluoride glass tube that has an OH content≦10 ppm, a F wt. % concentration≧0.5 wt. %.

Abstract: A production method of synthetic silica glass according to the present invention comprises a first step of ejecting a silicon compound and a combustion gas containing oxygen and hydrogen from a burner to effect hydrolysis of the silicon compound in oxyhydrogen flame to produce fine particles of silica glass, and thereafter depositing and vitrifying the fine particles of silica glass on a target opposed to the burner to obtain a synthetic silica glass ingot; a second step of heating the synthetic silica glass ingot or the like obtained in the first step up to a first retention temperature of not less than 900° C., retaining the ingot or the like at the first retention temperature, and cooling the ingot or the like at a temperature decrease rate of not more than 10° C./h down to a temperature of not more than 500° C.; and a third step of heating the synthetic silica glass ingot or the like obtained in the second step up to a second retention temperature of not less than 500° C.