6 May 2005 Apparatus for contamination control development in EUVA
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Abstract
For the development of chemical contamination control of extreme ultraviolet (EUV) lithography, especially to prolong the lifetime of optical elements, we had established and installed the experimental apparatus on Super-ALIS, a synchrotron facility beam-line, at NTT Atsugi laboratory, Japan. The apparatus is constructed with ultra high vacuum (UHV) components, then it is achieved that the residual gas pressure less than 5x10-7 Pa with no significant hydrocarbon contaminants. Using the setup, radiation-induced oxide formation and/or carbon deposition on EUVL optics mirror can be evaluated by EUV light irradiations and in-situ measurements of the reflectance under specified partial pressure of contaminants. Sub-system to introduce and control of pressure of water vapor in the irradiation chamber between 1x10-6 and 1x10-2 Pa is available. Preliminary results about dependency to water vapor partial pressure and EUV light intensity/dose indicate that the tendency that higher degree of oxidation of Mo/Si multi-layered mirror (MLM) surface is obtained from longer irradiation time and higher ambient water vapor pressure, whereas the Ru-capped mirrors maintains negligible oxidation if water pressure is 1x10-6 Pa. Electron-beam (EB) irradiation sub-system was also mounted for the accelerated and off-line oxidation and/or carbon deposition/cleaning evaluation. Vacuum ultraviolet (VUV) light (Xe2 excimer lamp: 172nm) irradiation sub-system with oxygen introduction is also available. Significant cleaning effect is obtained while oxidation of multi-layer mirror surface was observed. Estimated cleaning rate under the oxygen pressure of 100 Pa for sputtered carbon film is about 0.03 nm/min.
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Takashi Aoki, Takashi Aoki, Hiroyuki Kondo, Hiroyuki Kondo, Shuichi Matsunari, Shuichi Matsunari, Hiromitsu Takase, Hiromitsu Takase, Yoshio Gomei, Yoshio Gomei, Shigeru Terashima, Shigeru Terashima, } "Apparatus for contamination control development in EUVA", Proc. SPIE 5751, Emerging Lithographic Technologies IX, (6 May 2005); doi: 10.1117/12.600488; https://doi.org/10.1117/12.600488
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