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Atomic Data for Laser Produced Plasma Extreme Ultra Violet Light Source
K. Nishihara, K. Fujima1), H. Furukawa2), K. Gamada, T. Kagawa3), Y-G. Kang, T. Kato4), T. Kawamura5), F. Koike6), R. More4), M. Murakami, T. Nishikawa7), A. Sasaki8), A. Sunahara2), H. Tanuma9), V. Zhakhovskii, H. Nishimura, Y. Shimada2), S. Uchida)2), S. Fujioka,
N. Miyanaga and Y. Izawa
Institute of Laser Engineering, Osaka University, Suita, Osaka 565-0871,
1) Faculty of Engineering, Yamanashi University, Kofu, Yamanashi 400-8510,
2) Institute for Laser Technology, Suita, Osaka 565-0871,
3) Faculty of Science, Nara Women’s University, Nara 630-8506,
4) National Institute for Fusion Science, Toki, Gifu 509-5202,
5) Faculty of Engineering Science, Tokyou Institute of Technology, Yokohama, Kanagawa 220-8502,
6) Department of Medicine, Kitazato University, Sagamihara, Kanagawa 228-8555,
7) Faculty of Engineering, Okayama University, Okayama 700-8530,
8) Advanced Photon Research Center, JAERI-KANSAI, Kizu, Kyoto 619-0215,
9) Faculty of Science, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
Several EUV light sources have been promoted including laser-produced plasmas, and discharge plasmas. Many of the sources under consideration use 13.5 nm radiationswithin 2 % bandwidth from multicharged xenon and tin, because Mo/Si multiplayer mirrors have high reflectivity at this wavelength. A five-year-long project for Laser Produced Plasma EUV light source development was started as the Leading Projects promoted by MEXT since 2003. The project aims at understanding physics of LPP EUV light source for lithography, and providing database and guidelines for practical use. We will review present understanding of LPP for EUVL based on experiments and simulations.
At present main effort of laser experiments is devoted to characterization of laser produced plasmas such as plasma density profile, radiation spectrum from a few 10 eV to 2 keV and opacity measurements at laser intensity of 1010 - 1012 W/cm2 with various laser wavelengths. Solid targets of Sn, SnO2 and Xe are mostly used. Detail spectra from xenon ions with different ionization states have also been measured using ECR plasma and CHS magnetic confined plasma. They provide useful atomic data for benchmarking the codes. Theoretical works include detailed atomic modeling of such high-Z materials and radiation-hydrodynamics simulations of LPP with (n,l) splitting atomic model. We will discuss comparison of energy level and emissivity among different atomic codes, such as HULLAC, GRASP and RCI, and effects of satellite lines and opacity for the conversion efficiency from laser light to 13.5nm inband emission. Requirements of LPP for EUVL will be also presented from power balance point of view.
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