critical challenge for the success of extreme ultraviolet (EUV) lithography is to prevent collector mirror surface damage and reflectivity loss. Plasma debris and radiation damage the mirror and degrade the reflectivity. We study an innovative approach to the design and fabrication of collector mirror surface materials to improve collector lifetime. A Mo-Au Gibbsian segregation (GS) alloy is developed on silicon using a dc dual-magnetron cosputtering system, and the temperature effect on mirror damage is investigated. Result shows that a thin Au segregating layer is maintained during exposure, even though overall erosion is taking place. The reflective material underneath the segregating layer, Mo, is protected by the Au sacrificial layer, which is preferentially sputtered. Both theoretical and experimental studies have been performed to prove the effectiveness of the GS alloys for use as an EUV collector optics material.
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