Translator Disclaimer
21 March 2007 Long-term durability of a Ru capping layer for EUVL projection optics by introducing ethanol
Author Affiliations +
The inhibition of contamination of Ru-capped Mo/Si multilayer mirrors was systematically investigated by introducing ethanol into a controlled vacuum that mainly consisted of water vapor. Water vapor was introduced up to several partial pressures of 1.0X10-7 to 3.8X10-5 Pa. At the lowest ethanol pressure, the same degree of reflectance degradation as in the water-only case was observed. However, reflectance degradation was suppressed at ethanol pressures higher than 2.0X10-6 Pa. In the condition of ethanol pressure of 2.0X10-6 Pa, the long-term durability of a Ru capping layer was investigated up to an EUV dose of 6000 J/mm2. This dose was corresponded to the 1-year use of a mirror which would be irradiated by the maximum power expected in actual EUVL tools. As a result of this investigation, it was found that reflectance degradation of a Ru capping layer was suppressed to less than 0.5% until 6000 J/mm2 by introducing ethanol.
© (2007) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Yukinobu Kakutani, Masahito Niibe, Yoshio Gomei, Hiromitsu Takase, Shigeru Terashima, Shuichi Matsunari, Takashi Aoki, and Yasuaki Fukuda "Long-term durability of a Ru capping layer for EUVL projection optics by introducing ethanol", Proc. SPIE 6517, Emerging Lithographic Technologies XI, 651731 (21 March 2007); doi: 10.1117/12.711364;

Back to Top