Mitigation of fast ions generated from laser-produced Sn plasma for extreme ultraviolet light source by H{sub 2} gas
- Department of Electrical and Electronic Systems Engineering, Graduate School of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)
One of the serious problems in the laser-produced plasma for an extreme ultraviolet (EUV) light source used for the next generation lithography is the generation of fast ions that damage the EUV collector optics. In this study, the mitigation of fast ions from a laser-produced Sn plasma by a H{sub 2} background gas was investigated. It has been confirmed that H{sub 2} buffer gas at a pressure of 13.3 Pa has little influence on the transmission of 13.5 nm light with an optical path length of 200 mm. The sputtering of a dummy mirror by the fast ions generated from the laser-produced Sn plasma and their mitigation were investigated by visualizing the spatial distributions of sputtered atoms using the laser-induced fluorescence (LIF) imaging method. It was evaluated that the sputtering rate by the fast ions was reduced to less than approximately 5% by H{sub 2} gas with a column density of 1.2x10{sup 21} l/m{sup 2}. The dynamics and the chemical reaction of the plasma plume containing the high energy and high density ions in a H{sub 2} background gas were also investigated by a time-resolved emission spectroscopy as well as by LIF.
- OSTI ID:
- 21057554
- Journal Information:
- Journal of Applied Physics, Vol. 102, Issue 12; Other Information: DOI: 10.1063/1.2818026; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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