Abstract: A CaF2 polycrystalline body which is a polycrystalline body constituted of CaF2 and of which an average grain size of crystalline grains is 200 ?m or more, and a method for producing a CaF2 polycrystalline body, the method including a process of introducing a compact which is obtained by using a CaF2 powder raw material into a vacuum sintering furnace and sintering at a temperature of not higher than 1400° C. for six hours or more, thereby obtaining the CaF2 polycrystalline body.

Abstract: A CaF2 polycrystalline body which is a polycrystalline body constituted of CaF2 and of which an average grain size of crystalline grains is 200 ?m or more, and a method for producing a CaF2 polycrystalline body, the method including a process of introducing a compact which is obtained by using a CaF2 powder raw material into a vacuum sintering furnace and sintering at a temperature of not higher than 1400° C. for six hours or more, thereby obtaining the CaF2 polycrystalline body.

Abstract: An optical member made of silica glass manufactured by the direct method where a material gas comprising an organosilicon compound is allowed to react in an oxidizing flame, said optical member having a 2×1014 molecules/cm3 or less concentration of formyl radical generated by X-ray irradiation whose dose is 0.01 Mrad or more and 1 Mrad or less.

Abstract: In a method for producing a quartz glass member, an F2 laser is radiated onto a sample obtained from a quartz glass base material under a predetermined condition to judge whether or not a peak intensity of H2 Raman scattering light is decreased by not less than 80% as compared with a peak intensity of H2 Raman scattering light obtained for a sample not irradiated with the F2 laser. If the peak intensity of H2 Raman scattering light is decreased by less than 80%, then it is judged that the laser resistance of the quartz glass base material is sufficient, and the synthetic quartz glass member is processed from the base material. The compaction of the sample is also measured.

Abstract: A silica glass member of the present invention is one wherein when a composition thereof is expressed by SiOx, x is not less than 1.85 nor more than 1.95, wherein a concentration of hydrogen molecules included therein is not less than 1×1016 molecules/cm3 nor more than 5×1018 molecules/cm3, and wherein a difference A−B between an absorption coefficient A immediately before an end of irradiation with 1×104 pulses of ArF excimer laser light in an average one-pulse energy density of 2 mJ/cm2 and a second absorption coefficient B at 600 seconds after a stop of the irradiation with the ArF excimer laser light is not more than 0.002 cm−1. When this silica glass member is applied to an illumination optical system and/or a projection optical system in projection exposure apparatus, it becomes feasible to implement uniform exposure while reducing variation in illuminance on a reticle surface and in an exposure area on a wafer.

Abstract: An optical member made of silica glass manufactured by the direct method where a material gas comprising an organosilicon compound is allowed to react in an oxidizing flame,

Abstract: An optical member made of silica glass manufactured by the direct method where a material gas comprising an organosilicon compound is allowed to react in an oxidizing flame, said optical member having a 2×1014 molecules/cm3 or less concentration of formyl radical generated by X-ray irradiation whose dose is 0.01 Mrad or more and 1 Mrad or less.

Abstract: A silica glass member of the present invention is one wherein when a composition thereof is expressed by SiOx, x is not less than 1.85 nor more than 1.95, wherein a concentration of hydrogen molecules included therein is not less than 1×1016 molecules/cm3 nor more than 5×1018 molecules/cm3, and wherein a difference A−B between an absorption coefficient A immediately before an end of irradiation with 1×104 pulses of ArF excimer laser light in an average one-pulse energy density of 2 mJ/cm2 and a second absorption coefficient B at 600 seconds after a stop of the irradiation with the ArF excimer laser light is not more than 0.002 cm−1. When this silica glass member is applied to an illumination optical system and/or a projection optical system in projection exposure apparatus, it becomes feasible to implement uniform exposure while reducing variation in illuminance on a reticle surface and in an exposure area on a wafer.

Abstract: This invention provides a synthetic silica glass optical member used together with light having a specific wavelength of 250 nm or less, in which the difference between the maximum value and the minimum value of transmittance [%/cm] per cm in thickness for the light in a predetermined direction within a plane perpendicular to the optical axis is 2.0%/cm or less.

Abstract: An optical system is provided in a projection exposure apparatus for processing an excimer laser beam. The optical system includes at least one optical member made of silica glass having a chlorine concentration of about 1 ppm or less, and at least one optical member made of silica glass having a chlorine concentration of about 1 ppm to about 200 ppm.

Abstract: The invention relates to fluorine-containing silica glasses, and methods of their production. The silica glass may be used for an ultraviolet light optical system in which light in a wavelength region of 200 mn or less, such as an ArF (193 nm) excimer laser, is used The invention also relates to a projection exposure apparatus containing fluorine-containing glass of the invention.

Abstract: A silica glass forming method is a method of pressing a synthetic silica bulk having at least a set of opposed surfaces, on the surfaces under a high temperature condition by a presser, wherein an elastic member with permeability is placed between the presser and the surfaces of the synthetic silica bulk pressed by the presser and wherein the synthetic silica bulk is pressed through the elastic member by the presser. This method is able to reduce bubbles remaining inside the synthetic glass formed product after the forming to a sufficiently small amount. Therefore, it becomes feasible to provide the method that permits high-yield production of silica glasses with excellent optical characteristics.

Abstract: A silica glass member is provided for use in an optical system using light of a wavelength equal to or less than about 400 nm as a light source. The silica glass member has striae in a direction different from an optical axis of the optical system. The strength of the striae is equal to or less than about 2×10−6 in terms of refractive index differential.

Abstract: A method is provided for manufacturing a synthetic silica glass. The method includes the steps of emitting an oxygen containing gas and a hydrogen containing gas from a burner; emitting a mixture of an organic silicon compound and a halogen compound from the burner; and reacting the mixture with the oxygen containing gas and the hydrogen containing gas to synthesize the silica glass.

Abstract: An optical system is provided in a projection exposure apparatus for processing an excimer laser beam. The optical system includes at least one optical member made of silica glass having a chlorine concentration of about 1 ppm or less, and at least one optical member made of silica glass having a chlorine concentration of about 1 ppm to about 200 ppm.

Abstract: A method is provided for manufacturing a synthetic silica glass. The method includes the steps of maintaining a silica glass member, which is formed using a flame hydrolysis method and having an OH group concentration of about 500 ppm to about 1300 ppm, at a predetermined holding temperature for a predetermined period of time so as to substantially relax the structure of the silica glass member. The method further includes the step of subsequently cooling the silica glass member to a first predetermined temperature at a cooling rate of about 10 K/hour or less, and thereafter, cooling the silica glass member to a second predetermined temperature at a cooling rate of about 1 K/hour or less. The method further includes the step of further cooling the silica glass member to a third predetermined temperature at a cooling rate of about 10 K/hour or less.

Abstract: A method is provided for molding a synthetic silica glass member. The method includes accommodating a synthetic silica glass bulk inside a molding vessel; interposing an elastic member having a ventilating property between a pressing member and the synthetic silica glass bulk; providing a fastener for fastening at least peripheral edge portions of the elastic member to the pressing member; and pressing the synthetic silica glass bulk against the molding vessel by the pressing member in a high-temperature condition to mold the synthetic silica glass bulk into a synthetic silica glass member having a shape conforming to a shape of the space defined by the pressing member and the molding vessel, the synthetic silica glass bulk being pressed in such a manner that the pressing member and the elastic member tightly fasten to each other through the fastener.

Abstract: A method of manufacturing synthetic silica glass includes the steps of pressurizing a liquid storage tank including a liquid silicon compound therein, generating bubbles in the liquid silicon compound using a foamer, removing the bubbles using a degassed, displacing the liquid silicon compound into a vaporizer while controlling an amount of the liquid silicon compound displaced by a liquid mass flow meter, mixing the displaced liquid silicon compound with a carrier gas to generate a gaseous silicon compound, injecting the gaseous silicon compound into a synthesis furnace, and forming synthetic silica glass by hydrolyzing the gaseous silicon compound in the synthesis furnace.

Abstract: A method is provided for manufacturing a silica glass that is substantially free of chlorine. The method includes the step of separately expelling a silicon tetrafluoride gas, a combustion gas, and a combustible gas from a burner made of silica glass, the flow velocity of the silicon tetrafluoride gas being within the range of about 9 slm/cm2 to about 20 slm/cm2. The method further includes the steps of producing minute silica glass particles by reacting the silicon tetrafluoride gas with water produced by a reaction of the combustion gas with the combustible gas, depositing the minute silica glass particles on a target, and producing the silica glass by fusing and vitrifying the minute silica glass particles deposited on the target.

Abstract: An optical system is provided in a projection exposure apparatus for processing an excimer laser beam. The optical system includes at least one optical member made of silica glass having a chlorine concentration of about 1 ppm or less, and at least one optical member made of silica glass having a chlorine concentration of about 1 ppm to about 200 ppm.