Method of testing optical materials by irradiating with high energy density radiation, optical materials selected by said method and uses thereof

摘要

An optical material for lithographic applications is selected from crystal materials by a testing method. The crystal materials are preferably quartz and/or alkali or alkaline earth halides, especially fluorides, or mixed crystals. The testing method includes three tests to measure irreversible radiation damage: 1) the optical material is irradiated with ultraviolet radiation at 193 nm and the non-intrinsic fluorescence intensity at 740 nm is measured; 2) the optical material is irradiated with high energy density laser light and a change in respective absorptions before and after irradiation at 385 nm is measured; and 3) the optical material is irradiated with an X-ray or radioactive source to form all possible color centers and a difference of respective surface integrals of corresponding absorption spectra in ultraviolet spectral and/or visible spectral regions is measured before and after irradiation.