Abstract:
Hollow ingots of transparent synthetic vitreous silica glass of external diameter greater than 400 mm and internal diameter greater than 300 mm are disclosed. The ingots are substantially free from bubbles or inclusions greater than 100 mum in diameter, have no more than 100 ppB of any individual metallic impurity, and have chlorine concentration less than 5 ppM. Also disclosed are methods for producing such ingots, in which a porous soot body of density greater than 0.4 g/cm3 is deposited on an oxidation resistant mandrel. The soot body is dehydrated on a mandrel comprising graphite, carbon fibre reinforced carbon, silicon carbide, silicon impregnated silicon carbide, silicon carbide-coated graphite or vitreous silica, either under vacuum or in the presence of a reducing gas, and then sintered to transparent pore-free glass under vacuum or in an atmosphere of helium.
Abstract:
PROBLEM TO BE SOLVED: To provide an F-doped quartz glass material used in the lithographic application operating at a shorter wavelength than about 300 nm, which shows a lower polarization-induced birefringence or preferably, does not show the polarization-induced birefringence substantially even after being subjected to 10 million pulses of linearly polarized pulsed laser beam at 157 nm having a fluence of 250 μJ×cm -2 ×pulse -1 and a pulse length of 30 ns. SOLUTION: The F-doped synthetic quartz glass material contains, by weight, less than 50 ppm of Cl, less than 50 ppb of Na, less than 50 ppb in total of transition metals, and 0.1-5,000 ppm of fluorine. COPYRIGHT: (C)2008,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To prevent the emergence of striae, in a low expansion silica-titania glass suitable for manufacturing an extreme ultraviolet ray lithographic element. SOLUTION: The low expansion silica-titania glass appropriate for manufacturing the extreme ultraviolet lithographic element comprises a titania-containing silica glass, which has a titania content in the range of 5-12 mass% and contains a viscosity reducing dopant having a content in the range of 0.001 to 1 mass%. The element appropriate for extreme ultraviolet ray lithography is constituted by a titania-containing silica glass, which has a titania content in the range of 5-10 mass%, a viscosity reducing dopant having a content in the range of 0.001 to 1 mass%, a polished and formed surface, and a thermal expansion coefficient of 0±3 ppb/°C in a temperature range of 5-35°C. COPYRIGHT: (C)2008,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide titania-doped quartz glass having high homogeneity and providing high surface accuracy as required for EUV lithographic members such as EUV lithographic photomask substrates, and to provide EUV lithographic members such as EUV lithographic photomask substrates which are composed of titania-doped quartz glass and excellent in flatness and thermal expansion characteristics. SOLUTION: The titania-doped quartz glass contains 3-12 mass% of titania and has a titania concentration gradient less than or equal to 0.01 mass%/μm and has apparent transmittance at 440 nm wavelength light of at least 30% at a thickness of 6.35 mm. COPYRIGHT: (C)2007,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To provide an optical component of quartz glass which is optimized for use with linearly polarized UV laser radiation and particularly with respect to compaction and birefringence induced by anisotropic density change and suitable for use in a projection lens system for immersion lithography with an operating wavelength below 250 nm. SOLUTION: The quartz glass shows the combination of several characteristics: particularly a glass structure essentially without oxygen defects; a mean content of hydroxy groups of less than 60 wt ppm; a mean content of fluorine of less than 10 wt ppm; and a mean content of chlorine of less than 1 wt ppm. A method for producing such an optical component comprises the following steps: producing and drying an SiO 2 soot body under reducing conditions and treating the dried soot body before or during vitrification with a reagent reacting with oxygen defects of the quartz glass structure. COPYRIGHT: (C)2007,JPO&INPIT