Mitigation of fast ions generated from laser-produced Sn plasma for extreme ultraviolet light source by H2 gas

Daisuke Nakamura, Koji Tamaru, Yuki Hashimoto, Tatsuo Okada, Hiroki Tanaka, Akihiko Takahashi

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)

Abstract

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 H2 background gas was investigated. It has been confirmed that H2 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 H2 gas with a column density of 1.2× 1021 l m2. The dynamics and the chemical reaction of the plasma plume containing the high energy and high density ions in a H2 background gas were also investigated by a time-resolved emission spectroscopy as well as by LIF.

Original languageEnglish
Article number123310
JournalJournal of Applied Physics
Volume102
Issue number12
DOIs
Publication statusPublished - 2007

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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