Abstract: A method of cutting a strengthened glass including a front surface layer and a back surface layer in each of which a compression stress remains, respectively, and an intermediate layer formed between the front surface layer and the back surface layer, in which a tensile stress remains, the method includes: cutting the strengthened glass plate by heating the intermediate layer at an irradiation area of a laser beam at a temperature less than or equal to an annealing point while transmitting 70.0% to 99.8% of the laser beam having a wavelength between 800 to 1100 nm injected into the front surface and moving the irradiation area of the laser beam at a speed greater than or equal to 1.0 mm/sec, so that a crack, which penetrates the strengthened glass plate in a thickness direction of the strengthened glass plate, follows the irradiation area.

Abstract: A method of cutting a strengthened glass including, a front surface layer and a back surface layer each having a remaining compression stress, respectively, and an intermediate layer formed between the front surface layer and the back surface layer, having an internal remaining tensile stress, the method includes heating the intermediate layer at an irradiation area of a laser beam at a temperature less than or equal to an annealing point to generate a tensile stress less than a value of the internal remaining tensile stress of the intermediate layer or a compression stress at the center of the irradiation area for suppressing the propagation of the crack.

Abstract: The present invention relates to an alkali-free glass having a strain point of 735° C. or higher, an average thermal expansion coefficient at from 50 to 350° C. of from 30×10?7 to 40×10?7/° C., a temperature T2 at which a glass viscosity is 102 dPa·s of 1,710° C. or lower, a temperature T4 at which a glass viscosity is 104 dPa·s of 1,340° C. or lower, and a devitrification temperature of 1,330° C. or lower, the alkali-free glass including, in terms of mol % on the basis of oxides: SiO2 66 to 69, Al2O3 12 to 15, B2O3 0 to 1.5, MgO 6 to 9.5, CaO 7 to 9, SrO 0.5 to 3, BaO 0 to 1, and ZrO2 0 to 2, in which MgO+CaO+SrO+BaO is from 16 to 18.2, MgO/(MgO+CaO+SrO+BaO) is 0.35 or more, MgO/(MgO+CaO) is 0.40 or more and less than 0.52, and MgO/(MgO+SrO) is 0.45 or more.

Abstract: The present invention relates to a method for producing a glass body containing: hydrolyzing a silicon compound and a compound containing a metal serving as a dopant, in a flame projected from a burner to form glass fine particles; and depositing and growing the formed glass fine particles on a base material, in which a raw material mixed gas containing a gas of the silicon compound, a gas of the compound containing a metal serving as a dopant, and either one of a combustible gas and a combustion supporting gas is fed into a central nozzle (A) positioning in the center of the burner; the other gas of the combustible gas and the combustion supporting gas is fed into a nozzle (B) different from the central nozzle (A) of the burner; a combustible gas or a combustion supporting gas is arbitrarily fed into a nozzle different from the nozzles (A) and (B); and a flow rate of the raw material mixed gas is 50% or more and not more than 90% of the largest flow rate among flow rate(s) of the combustible gas(ses) and the

Abstract: The present invention relates to a process for production of a TiO2—SiO2 glass body, comprising: a step of, when an annealing point of a TiO2—SiO2 glass body after transparent vitrification is taken as T1 (° C.), heating the glass body after transparent vitrification at a temperature of T1+400° C. or more for 20 hours or more; and a step of cooling the glass body after the heating step up to T1?400 (° C.) from T1 (° C.) in an average temperature decreasing rate of 10° C./hr or less.

Abstract: The present invention relates to an alkali-free glass having a strain point of 725° C. or higher, an average thermal expansion coefficient at from 50 to 300° C. of from 30×10?7 to 40×10?7/° C., a temperature T2 at which a glass viscosity is 102 dPa·s of 1,710° C. or lower, and a temperature T4 at which a glass viscosity is 104 dPa·s of 1,320° C. or lower, the alkali-free glass including, in terms of mol % on the basis of oxides, SiO2: 66 to 70, Al2O3: 12 to 15, B2O3: 0 to 1.5, MgO: more than 9.5 and 13 or less, CaO: 4 to 9, SrO: 0.5 to 4.5, BaO: 0 to 1, and ZrO2: 0 to 2, in which MgO+CaO+SrO+BaO is from 17 to 21, MgO/(MgO+CaO+SrO+BaO) is 0.4 or more, MgO/(MgO+CaO) is 0.4 or more, MgO/(MgO+SrO) is 0.6 or more, and the alkali-free glass does not substantially contain an alkali metal oxide.

Abstract: The present invention relates to a substrate for EUV lithography optical member, comprising a silica glass containing TiO2, in which the substrate has two opposite surfaces, and the substrate has temperatures at which a coefficient of linear thermal expansion (CTE) is 0 ppb/° C. (Cross-Over Temperature: COT), and in which the two opposite surfaces have difference in the COTs of 5° C. or more.

Abstract: It is an object of the present invention to provide a glass substrate having plural through-holes which is not likely to peel from a silicon wafer, even though laminated on and jointed to a the silicon wafer and then subjected to heat treatment. The above object is accomplished by a glass substrate having an average thermal expansion coefficient of from 10×10?7 to 50×10?7/K within a range of from 50° C. to 300° C., having plural through-holes with a taper angle of from 0.1 to 20° and having a thickness of from 0.01 to 5 mm.

Abstract: A process for producing a porous quartz glass body containing hydrolyzing a metal dopant precursor and an SiO2 precursor in a flame of a burner to form glass fine particles, and depositing and growing the formed glass fine particles on a base material, in which the burner has at least two nozzles, and in which a mixed gas containing (A) a metal dopant precursor gas, (B) an SiO2 precursor gas, (C) one gas of H2 and O2, and (D) one or more gases selected from the group consisting of a rare gas, N2, CO2, a hydrogen halide and H2O, with a proportion of the gas (D) being from 5 to 70 mol %; and (E) the other gas of H2 and O2 of (C), are fed into different nozzles of the burner from each other.

Abstract: A silica glass containing TiO2, which has a fictive temperature of at most 1,200° C., a F concentration of at least 100 ppm and a coefficient of thermal expansion of 0±200 ppb/° C. from 0 to 100° C. A process for producing a silica glass containing TiO2, which comprises a step of forming a porous glass body on a target quartz glass particles obtained by flame hydrolysis of glass-forming materials, a step of obtaining a fluorine-containing porous glass body, a step of obtaining a fluorine-containing vitrified glass body, a step of obtaining a fluorine-containing formed glass body and a step of carrying out annealing treatment.

Abstract: The present invention relates to a method for producing an article having a fine concave and convex structure on a surface thereof, comprising the following steps (i) to (iii): (i) step of sandwiching a photocurable composition between a mold having an inverted structure of the fine concave and convex structure on a surface thereof and a substrate; (ii) step of irradiating the photocurable composition with light; and (iii) step of separating the mold from the cured product to obtain an article comprising the substrate having on a surface thereof the cured product having the fine concave and convex structure on a surface thereof, in which the mold contains TiO2-containing quartz glass, and at least the step (i) is conducted in a helium gas atmosphere.

Abstract: The present invention relates to a substrate for EUV lithography optical member, comprising a silica glass containing TiO2, in which the substrate has two opposite surfaces, and the substrate has temperatures at which a coefficient of linear thermal expansion (CTE) is 0 ppb/° C. (Cross-Over Temperature: COT), and in which the two opposite surfaces have difference in the COTs of 5° C. or more.

Abstract: The present invention relates to a TiO2-containing silica glass containing TiO2 in an amount of from 5 to 10 mass % and at least one of B2O3, P2O5 and S in an amount of from 50 ppb by mass to 5 mass % in terms of the total content.

Abstract: The present invention relates to a method for producing a silica glass substrate for an imprint mold, containing: obtaining a glass body from a glass-forming raw material containing an SiO2 precursor; machining the glass body into a glass substrate having a predetermined shape; and removing an affected layer on a surface of the glass substrate, to produce a silica glass substrate for an imprint mold having a fictive temperature distribution in a region from the surface to a depth of 10 ?m on the side to be subjected to a transfer pattern formation of the glass substrate being within ±30° C.

Abstract: The present invention relates to a process for production of a synthetic quartz glass having a fluorine concentration of 1,000 mass ppm or more, the process comprising: (a) a step of depositing and growing quartz glass fine particles obtained by flame hydrolysis of a glass forming raw material onto a substrate, to thereby form a porous glass body; (b) a step of keeping the porous glass body in a reaction vessel that is filled with elemental fluorine (F2) or a mixed gas comprising elemental fluorine (F2) diluted with an inert gas and contains a solid metal fluoride, to thereby obtain a fluorine-containing porous glass body; and (c) a step of heating the fluorine-containing porous glass body to a transparent vitrification temperature, to thereby obtain a fluorine-containing transparent glass body.

Abstract: The present invention relates to a TiO2-containing silica glass having a TiO2 content of 7.5 to 12% by mass, a fictive temperature of 1,000° C. or higher, and a temperature at which a coefficient of linear thermal expansion is 0 ppb/° C. being within the range of 40 to 110° C.

Abstract: The present invention relates to a process for production of a TiO2—SiO2 glass body, comprising a step of, when an annealing point of a TiO2—SiO2 glass body after transparent vitrification is taken as T1(° C.), holding the glass body after transparent vitrification in a temperature region of from T1?90(° C.) to T1?220(° C.) for 120 hours or more.

Abstract: The present invention provides a TiO2—SiO2 glass whose coefficient of linear thermal expansion in the range of the time of irradiation with EUV light is substantially zero when used as an optical member of an exposure tool for EUVL and which has extremely high surface smoothness. The present invention relates to a TiO2-containing silica glass having a TiO2 content of from 7.5 to 12% by mass, a temperature at which a coefficient of linear thermal expansion is 0 ppb/° C., falling within the range of from 40 to 110° C., and a standard deviation (?) of a stress level of striae of 0.03 MPa or lower within an area of 30 mm×30 mm in at least one plane.

Abstract: The present invention relates to a process for production of a TiO2—SiO2 glass body, comprising: a step of, when an annealing point of a TiO2—SiO2 glass body after transparent vitrification is taken as T1 (° C.), heating the glass body after transparent vitrification at a temperature of T1+400° C. or more for 20 hours or more; and a step of cooling the glass body after the heating step up to T1?400 (° C.) from T1 (° C.) in an average temperature decreasing rate of 10° C./hr or less.

Abstract: The present invention provides a TiO2—SiO2 glass in which when used as an optical member for an exposure tool for EUVL, a thermal expansion coefficient is substantially zero at the time of irradiation with high-EUV energy light, and physical properties of a multilayer can be kept over a long period of time by releasing hydrogen from the glass. The present invention relates to a TiO2-containing silica glass having a fictive temperature of 1,100° C. or lower, a hydrogen molecule concentration of 1×1016 molecules/cm3 or more, and a temperature, at which a linear thermal expansion coefficient is 0 ppb/° C., falling within the range of from 40 to 110° C.