| 摘要 |
An object of the present invention is to provide a silica glass optical material having a high initial transmittance with respect to vacuum ultraviolet radiation 155 to 195 nm in wavelength, a high precision, a high durability, and an excellent homogeneity, as well as to a method for producing the same and a projection lens. Means for Solving the ProblemsÜ A silica glass optical material for projection lens to be used in vacuum ultraviolet radiation lithography using radiations from 155 to 195 nm in wavelength, wherein, said silica glass optical material is of ultrahigh purity, contains from 1 to 10 wtppm of OH groups, from 100 to 10,000 wtppm of F, and from 1 x 10<17> to 1 x 10<19> molecules/cm<3> of H2, and has a distribution in concentration of F that is axially symmetrical to the central axis. <IMAGE> |
