SILICA GLASS OPTICAL MATERIAL FOR EXCIMER LASER AND EXCIMER LAMP, AND METHOD FOR PRODUCTION THEREOF

摘要

PURPOSE: To provide a silica glass optical material that has high initial transmission to the excimer laser or excimer lamp of 155-195 nm wavelength and a small fluctuation range in the refractive index (Δn) and shows excellent durability under irradiation therewith for a long time. CONSTITUTION: This invention relates to a silica glass optical material for the rays or beams from an Excimer laser and Excimer lamp and characteristically has the following physical and chemical properties: the silica glass optical glass is ultra-high pure, has an OH group content of 1-100 wt.ppm, a H2 content of 5x1016-5x1019 molecules/cm3, and a F content of 10-10,000 wt.ppm, substantially no content of halogens other than F and a fluctuation range in the refractive index (Δn) of 3x10-6-3x10-7.