Quartz glass blank for an optical component, and manufacturing procedure and use thereof

Abstract

The present invention relates to a quartz glass blank for an optical component for transmission of ultraviolet radiation of a wavelength of 250 nm or shorter, and to a use of the quartz glass blank in microlithography in combination with ultraviolet radiation of a wavelength of 250 nm or shorter. Moreover, the invention relates to a procedure for manufacture of the quartz glass blank. A quartz glass blank of the described type should show little induced absorption and be optimized with respect to compaction and decompaction. The quartz glass blank according to the invention is characterized by the following properties: a glass structure essentially free of oxygen defect sites, an H2-content in the range of 0.1×1016 molecules/cm3 to 4.0×1016 molecules/cm3, an OH-content in the range of 125 wt-ppm to 450 wt-ppm, an SiH group-content of less than 5×1016 molecules/cm3, a refractive index inhomogeneity, Δn, of less than 2 ppm, and a stress birefringence of less than 2 nm/cm. In the use according to the invention, the quartz glass blank complies with dimensioning rules (2), (3), and (4) in terms of its minimal and maximal hydrogen contents and OH-content, CH2min, CH2max, and COH, respectively, with P being the pulse number and ε being the energy density (in mJ/cm2): CH2min[molecules/cm3]=1×106 ε2P  (2), CH2max[molecules/cm3]=2×1018 ε  (3), COH[wt-ppm]=1,700×ε[mJ/cm2]0.4±50  (4). The procedure according to the invention is characterized in that a mixed quartz glass is generated from a first and a second quartz glass by mixing the two quartz glasses in the course of a homogenization treatment.

Dependencies are inferred from the claim text.