TIO2-CONTAINING SILICA GLASS FOR OPTICAL MEMBER FOR EUV LITHOGRAPHY

摘要

The present invention provides a TiO2-containing silica glass from which a transparent extremely low thermal expansion glass having excellent transparency and having a temperature region in which the coefficient of thermal expansion is substantially zero can be obtained. The present invention relates to a TiO2-containing silica glass for optical member for EUV lithography, having a TiO2 concentration of from 3 to 14% by mass; an internal transmittance per 1-mm thickness in a wavelength region of from 400 to 700 nm, T400-700, of 97% or more; and an internal transmittance per 1-mm thickness in a wavelength region of from 400 to 3,000 nm, T400-3000, of 70% or more.