TIO2-CONTAINING SILICA GLASS AND OPTICAL MEMBER FOR LITHOGRAPHY USING THE SAME

摘要

The present invention provides a TiO2-SiO2 glass whose coefficient of linear thermal expansion upon irradiation with high EUV energy light is substantially zero, which is suitable as an optical member of an exposure tool for EUVL. The present invention relates to a TiO2-containing silica glass having a halogen content of 100 ppm or more; a fictive temperature of 1,100 °C or lower; an average coefficient of linear thermal expansion in the range of from 20 to 100 °C of 30 ppb/°C or lower; a temperature width DT, in which a coefficient of linear thermal expansion is 0 ± 5 ppb/°C, of 5°C or greater; and a temperature, at which a coefficient of linear thermal expansion is 0 ppb/°C, falling within the range of from 30 to 150 °C.