Abstract: A burner for use in the manufacture of synthetic quartz glass is provided, which comprises a main burner (7) comprising a multi-tube assembly (1) including a center tube (2) for feeding a silica-forming compound, a first enclosure tube (3) surrounding the center tube for feeding a combustion-supporting gas, and a second enclosure tube (4) surrounding the first enclosure tube for feeding a combustible gas; a tubular shell (5) surrounding the multi-tube assembly for feeding a combustible gas; and a plurality of nozzles (6) disposed within the tubular shell for feeding a combustion-supporting gas. A double-tube assembly (8) is disposed so as to surround the forward opening of the main burner (7) for feeding a combustion-supporting gas. Synthetic quartz glass ingots having high optical homogeneity are produced.

Abstract: A burner for use in the manufacture of quartz glass is provided, which comprises a triple-tube assembly of a center tube for feeding a silane or siloxane compound, an intermediate tube for feeding oxygen, and an outer tube for feeding hydrogen, a first tubular shell surrounding the triple-tube assembly for feeding hydrogen, a plurality of first nozzles disposed within the first tubular shell for feeding oxygen, a second tubular shell surrounding the first tubular shell for feeding hydrogen, and a plurality of second nozzles disposed within the second tubular shell for feeding oxygen. Synthetic quartz glass ingots having high optical homogeneity are produced.

Abstract: A cylindrical, chlorine-free synthetic quartz glass blank of a specific size obtained by homogenizing a synthetic quartz glass ingot having periodic striae along a direction of growth has (a) striae grades in the working and off-axis directions which meet grade A of U.S. military specification MIL-G-174B, (b) average hydroxyl group concentrations in the working and off-axis directions of 700 to 1,000 ppm each, (c) average fictive temperatures in the working and off-axis directions of 850 to 950° C. each, and (d) a refractive index distribution for 633 nm wavelength light in the working direction of at most 1×10−6. The blank has a good transmittance to laser light, undergoes little deterioration when irradiated with laser light, and is particularly suitable for ArF excimer laser-related applications.

Abstract: A process for producing synthetic quartz glass using a burner composed of a plurality of concentric nozzles involves the steps of feeding a silica-forming raw material gas and a fluorine compound gas to a reaction zone from a center nozzle, feeding oxygen gas from a second nozzle outside the center nozzle, and feeding oxygen gas and/or hydrogen gas from a third nozzle. The silica-forming raw material gas is hydrolyzed to form fine particles of silica, which particles are deposited on a rotatable substrate so as to form a porous silica matrix, which is then fused to give the quartz glass. The flow rate of the oxygen gas fed from the second nozzle and the flow rate of the raw material gas are controlled so as to provide a 1.1- to 3.5-fold stoichiometric excess of oxygen. The excess oxygen suppresses Si—Si bond formation in the quartz glass, enabling the production of synthetic quartz glass having a high transmittance in the vacuum ultraviolet region.

Abstract: A cylindrical, chlorine-free synthetic quartz glass blank of a specific size obtained by homogenizing a synthetic quartz glass ingot having periodic striae along a direction of growth has (a) striae grades in the working and off-axis directions which meet grade A of U.S. military specification MIL-G-174B, (b) average hydroxyl group concentrations in the working and off-axis directions of 700 to 1,000 ppm each, (c) average fictive temperatures in the working and off-axis directions of 850 to 950° C. each, and (d) a refractive index distribution for 633 nm wavelength light in the working direction of at most 1×10−6. The blank has a good transmittance to laser light, undergoes little deterioration when irradiated with laser light, and is particularly suitable for ArF excimer laser-related applications.

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: A synthetic quartz glass member having (i) a change of transmittance at 193 nm of up to 0.002 cm−1 as expressed in extinction coefficient when 4×104 shots of ArF excimer laser light are irradiated at 2 mJ/cm2/pulse, (ii) an initial transmittance of at least 99.6% at 193 nm, (iii) a hydrogen molecule content of at least 5×1017 molecules/cm3, (iv) a refractive index amplitude of up to 1×10−6, and (v) a birefringence of up to 1 nm/cm finds use in an excimer laser because it experiences a minimized change of light transmittance.

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: There is disclosed a synthetic fused silica member used at a wavelength of 200 nm or less which has a hydroxyl group-content of 1 to 50 ppm and a fluorine-content of 100 to 1000 ppm, and contains no chlorine, and has a birefringence of the synthetic fused silica member of 2 nm/cm or less. The synthetic fused silica member can be used as a synthetic fused silica substrate for photomask, or in an optical system wherein a fluorine excimer laser is used as a light source. There can be provided a synthetic fused silica member which can efficiently transmit a light having a wavelength as 200 nm or less, especially fluorine excimer laser (157 nm), and does not suffer from lowering of transmittance due to damage.

Abstract: A process for producing synthetic quartz glass using a burner composed of a plurality of concentric nozzles involves the steps of feeding a silica-forming raw material gas and a fluorine compound gas to a reaction zone from a center nozzle, feeding oxygen gas from a second nozzle outside the center nozzle, and feeding oxygen gas and/or hydrogen gas from a third nozzle. The silica-forming raw material gas is hydrolyzed to form fine particles of silica, which particles are deposited on a rotatable substrate so as to form a porous silica matrix, which is then fused to give the quartz glass. The flow rate of the oxygen gas fed from the second nozzle and the flow rate of the raw material gas are controlled so as to provide a 1.1- to 3.5-fold stoichiometric excess of oxygen. The excess oxygen suppresses Si—Si bond formation in the quartz glass, enabling the production of synthetic quartz glass having a high transmittance in the vacuum ultraviolet region.

Abstract: Synthetic quartz glass is produced by feeding a silica-forming raw material gas, hydrogen gas, oxygen gas and a fluorine compound gas from a burner to a reaction zone, flame hydrolyzing the silica-forming raw material gas in the reaction zone to form fine particles of fluorine-containing silica, depositing the silica fine particles on a rotatable substrate in the reaction zone so as to create a fluorine-containing porous silica matrix, and heat vitrifying the porous silica matrix in a fluorine compound gas-containing atmosphere. This process enables the low-cost manufacture of a synthetic quartz glass having a higher and more uniform transmittance to light in the vacuum ultraviolet region than has hitherto been achieved.