Spectroscopic study of debris mitigation with minimum-mass Sn laser plasma for extreme ultraviolet lithography
- Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527 (Japan)
An experimental study was made of a target consisting of the minimum mass of pure tin (Sn) necessary for the highest conversion to extreme ultraviolet (EUV) light while minimizing the generation of plasma debris. The minimum-mass target comprised a thin Sn layer coated on a plastic shell and was irradiated with a Nd:YAG laser pulse. The expansion behavior of neutral atoms and singly charged ions emanating from the Sn plasma were investigated by spatially resolved visible spectroscopy. A remarkable reduction of debris emission in the backward direction with respect to the incident laser beam was demonstrated with a decrease in the thickness of the Sn layer. The optimal thickness of the Sn layer for a laser pulse of 9 ns at 7x10{sup 10} W/cm{sup 2} was found to be 40 nm, at which low-debris emission in the backward direction and a high conversion to 13.5 nm EUV radiation were simultaneously attained.
- OSTI ID:
- 20779174
- Journal Information:
- Applied Physics Letters, Vol. 88, Issue 17; Other Information: DOI: 10.1063/1.2199494; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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