Efficient 13.5nm extreme ultraviolet emission from Sn plasma irradiated by a long CO2 laser pulse

Abstract

The effect of pulse duration on in-band (2% bandwidth) conversion efficiency (CE) from a C O 2 laser to 13.5 nm extreme ultraviolet(EUV) light was investigated for Sn plasma. It was found that high in-band CE, 2.6%, is consistently obtained using a C O 2 laser with pulse durations from 25 to 110 ns . Employing a long pulse, for example, 110 ns , in a C O 2 laser system used in an EUV lithography source could make the system significantly more efficient, simpler, and cheaper as compared to that using a short pulse of 25 ns or shorter.