Abstract

Emission characteristics for laser-driven EUV lithographic plasma sources have been studied exhaustively for the last four years. While debris issues now dominate research in this area, final details are being concluded on our understanding of material spectra and radiation transport of 13 nm light in laser-plasmas. Spectra of Sn, Cu, Xe, and Au were studied in the 2-20 nm region with transmission grating spectroscopy using 248 nm illumination. Additionally, conclusive results were obtained with 308 nm light, showing the pulselength threshold below which plumes no longer limit the transmission of (and thus the conversion efficiency to) 13 nm radiation.

© 1994 Optical Society of America