SUBSTRATE FOR EUVL OPTICAL MEMBER

摘要

The present invention relates to a substrate for EUV lithography optical member, comprising a silica glass containing TiO2, in which the substrate has two opposite surfaces, and the substrate has temperatures at which a coefficient of linear thermal expansion (CTE) is 0 ppb/° C. (Cross-Over Temperature: COT), and in which the two opposite surfaces have difference in the COTs of 5° C. or more.