Abstract: A process for producing a glass body, the process including flowing oxygen gas from a burner in a furnace at a flow rate of greater than 12.0 standard liters per minute and flowing a precursor gas mixture from the burner. The process further including oxidizing the precursor gas mixture with the oxygen gas to form glass particles and depositing the glass particles on a collection cup to form the glass body.

Abstract: A silica-titania glass substrate comprising: (i) a composition comprising 5 weight percent to 10 weight percent TiO2; (ii) a coefficient of thermal expansion (CTE) at 20° C. in a range from ?45 ppb/K to +20 ppb/K; (iii) a crossover temperature (Tzc) in a range from 10° C. to 50° C.; (iv) a slope of CTE at 20° C. in a range from 1.20 ppb/K2 to 1.75 ppb/K2; (v) a refractive index variation of less than 140 ppm; and (vi) 600 ppm OH group concentration or greater. The substrate can have a mass of 1 kg or greater and less than 0.05 gas inclusions per cubic inch via a method comprising (i) forming the substrate from soot particles comprising SiO2 and TiO2, and (ii) subjecting the substrate to an environment having an elevated temperature and an elevated pressure for a period of time until the substrate comprises less than 0.05 gas inclusions per cubic inch.

Abstract: A glass article for use in Extreme Ultra-Violet Lithography (EUVL) is provided. The glass article includes a silica-titania glass having a compositional gradient through the glass article, the compositional gradient being defined by the functions: [TiO2]=(c+f(x,y,z)), and [SiO2]=(100?{c+f(x,y,z)}??(x,y,z)) wherein [TiO2] is the concentration of titania in wt. %, [SiO2] is the concentration of silica in wt. %, c is the titania concentration in wt. % for a predetermined zero crossover temperature (Tzc), f(x, y, z) is a function in three-dimensional space that defines the difference in average composition of a volume element centered at the coordinates (x, y, z) with respect to c, and ?(x, y, z) is a function in three-dimensional space that defines the sum of all other components of a volume element centered at the coordinates (x, y, z).

Abstract: A glass article for use in Extreme Ultra-Violet Lithography (EUVL) is provided. The glass article includes a silica-titania glass having a compositional gradient through the glass article, the compositional gradient being defined by the functions: [TiO2]=(c+f(x,y,z)), and [SiO2]=(100?{c+f(x,y,z)}??(x,y,z)) wherein [TiO2] is the concentration of titania in wt. %, [SiO2] is the concentration of silica in wt. %, c is the titania concentration in wt. % for a predetermined zero crossover temperature (Tzc), f(x, y, z) is a function in three-dimensional space that defines the difference in average composition of a volume element centered at the coordinates (x, y, z) with respect to c, and ?(x, y, z) is a function in three-dimensional space that defines the sum of all other components of a volume element centered at the coordinates (x, y, z).

Abstract: A method for forming a silica glass blank includes generating soot using an array of soot producing burners, directing the soot along a first direction onto a bait, collecting the soot on the bait, imparting relative oscillatory motion having a repeat period between the array of soot producing burners and the bait along a second direction orthogonal to the first direction while collecting the soot, and offsetting the relative oscillatory motion by a selected distance along the second direction after each repeat period.

Abstract: This disclosure is directed to tailoring and improving the expansivity of low thermal expansion silica-titania glass through changes in the [OH] content and fictive temperature of the glasses. The [OH] concentration in the glass can be in the range of 600-2500 ppm. The fictive temperature, TF is less than 900° C.

Abstract: The invention is directed to a method for reducing striae in ultra-low expansion glass, for example, silica-titania glass, by heat-treating the glass at temperatures above 1600° C. for a time in the range of 72-288 hours. The silica-titania glass is formed by substantially simultaneously forming, collecting and consolidating a silica-titania soot formed in one or a plurality of burners using silicon-containing feedstock and a titanium-containing feedstock. In one embodiment of the invention the glass is heat treated without forcing the glass to flow or “move”. The invention was found to reduce the magnitude of striae in an ultra-low expansion glass by at least 50%, and particularly reduces most of the “higher frequency” striae.

Abstract: The invention in one aspect is directed to a silica-titania glass have reduced striae and reduced inclusions, the glass have a point-to-point variation in titania content is 0.1 wt % or less through its thickness and a CTE of 0±3 ppb/° C. in the temperature range 5-35° C. The invention is further directed to a method for producing by using a method in which the time for repetition of the oscillation patterns used in the process are 10 minutes or less during preparation of the glass and after the glass has been prepared heating the glass at a temperature in the range of 1650-1700° C. for a time in the range of 4-10 day to reduce inclusions in the glass.

Abstract: A method for forming a silica glass blank includes generating soot using an array of soot producing burners, directing the soot along a first direction onto a bait, collecting the soot on the bait, imparting relative oscillatory motion having a repeat period between the array of soot producing burners and the bait along a second direction orthogonal to the first direction while collecting the soot, and offsetting the relative oscillatory motion by a selected distance along the second direction after each repeat period.