Abstract: A method of molding a silica glass comprises: a first step of accommodating the silica glass containing OH groups in a concentration of 900 ppm to 1300 ppm by mass in a hollow portion of a mold provided with a press portion; a second step of molding the silica glass in a predetermined form by pressing the same by means of the pressing portion so that a maximum pressure can be 0.2 Kg/cm2 to 0.8 Kg/cm2 while heating the silica glass so that the temperature of the same can be within a hold temperature range of 1530° C. to 1630° C.; and a third step of cooling the molded silica glass.

Abstract: A thermal treatment apparatus includes a furnace of a refractory, a stage capable of carrying synthetic silica glass and moving between a first stage position for letting the synthetic silica glass into the furnace and a second stage position for letting the synthetic silica glass out of the furnace, a heat generator for heating the synthetic silica glass, and a driving section connected to the stage, for moving the stage between the first stage position and the second stage position. The thermal treatment apparatus also can include a rotational driving section for rotating the stage.

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.

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: An apparatus is provided for synthesizing a silica glass ingot. The appartus includes a stage having a target plate thereover, the target plate being rotatable relative to the stage around a predetermined vertical axis, and a furnace for reacting material gas with combustion gas to synthesize the silica glass ingot on the target plate; the furnace having an opening at its bottom. The appratus further includes an elevation system that moves the stage in a vertical direction parallel to the predetermined vertical axis so as to vertically move the target plate through the opening of the furnace, the elevation system supporting the stage from at least one side of the stage and lacking a structure directly below the stage that would substantially interfere with the vertical movement of the stage.

Abstract: A method for manufacturing quartz glass in a flame hydrolysis reaction inside a furnace, including the steps of mixing a gas containing Si, a combustion-supporting gas, and a combustible gas and discharging this mixed gas from a burner; producing a quartz glass powder by causing the mixed and discharged gases to react in a flame within the furnace while an opening area of an opening and shutting system of the furnace is controlled; and producing a quartz glass ingot by depositing and vitrifying the quartz glass powder on a target surface facing an interior of the furnace, wherein said producing step includes the step of controlling the opening area of the opening and shutting system of the furnace in accordance with the amount of growth of the ingot on the target surface.

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 nm 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.