Manufacture of extreme ultraviolet optical element comprises providing forming sol into titania-containing silica shaped gel having homogenous distribution of titania, drying the gel, and heating silica body to form glass body

摘要

An extreme ultraviolet optical element is made by: providing an aqueous sol including a solid phase of titania-containing silica powder; forming the sol into a titania-containing silica shaped gel having a homogenous distribution of titania; drying the titania-containing silica gel to provide a dried titania-containing silica body; and heating the titania-containing silica body to a temperature to form glass body (18). An Independent claim is also included for a titania-containing silica glass body having a length greater than 10 cm, a width greater than 10 cm, a titania concentration of 6.5-7.5 wt.%, and a coefficient of thermal expansion (CTE) variation of less than 1 ppb/degrees C.