TITANIA-DOPED QUARTZ GLASS AND MAKING METHOD, EUV LITHOGRAPHIC MEMBER AND PHOTOMASK SUBSTRATE

摘要

Titania doped quartz glass for EUV lithographic material is provided to have high homogeneity sufficient to endow excellent surface precision to the lithographic material, and to make EUV lithographic material with planarity or thermal expansion property by comprising titania with desired content and defining specific apparent permeability of the glass. The titania doped quartz glass includes 3-12wt.% of titania with concentration gradient of less than 0.01wt.% /micron. The quartz glass has more than 30% of apparent permeability at 440nm in case thickness of the glass is 6.35mm, and also double refraction of less than 20nm/cm. The quartz glass has average line thermal expansion coefficient of -30 to +30ppb/deg.C at 10-30deg.C, distribution of OH group concentrations less than 400ppm and chlorine concentration of 1-500ppm. The quartz glass does not produce crystalline materials by annealing process at 700deg.C.