In this article, the authors present a novel study of EUV-induced damage thresholds for grazing incidence mirrors based on gold films, as well as for Mo/Si multilayer mirrors, through the use of a nanosecond table-top EUV source. For gold films, a linear behavior between threshold fluence and film thickness was observed, indicating a thermally dominated process. For Mo/Si multilayer mirrors, on the other hand, two damage regimes were observed, corresponding to spotlike and crater damage. Fused silica exhibits very smooth ablation craters, indicating a direct photon induced, bond-breaking process. Silicon shows the highest damage threshold of all investigated substrate and coating materials. The experiments reported in this work demonstrate that single-pulse EUV damage thresholds of substrate materials are higher than those of thin reflective coatings (a fact that is well known for higher UV and visible wavelengths). Thus, metal or multilayer films immediately exposed to EUV radiation will clearly be the limiting factor for high fluence applications of 13.5 nm radiation.
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