Characterization of Extreme UV Radiation from Laser Produced Spherical Tin Plasmas for Use in Lithography

Abstract

A new research project on extreme ultraviolet(EUV) source development has been started utilizing resources of laser fusion research. The main task of the project is to provide a scientific basis for generating efficient, debris-free, high power EUV plasma source for production of semiconductor devices. Spherical solid-tin targets were illuminated uniformly with twelve beams from GEKKO XII to create spherical plasmas, and EUV emission spectra were absolutely measured. The highest conversion efficiency of 3 % to 13.5 nm EUV light in 2 % bandwidth was attained at irradiance of around 5×1010W⁄cm2. The experimental data were well reproduced by a theoretical model taking power balance in the EUV plasma into consideration.