Liquid-jet laser–plasma extreme ultraviolet sources: from droplets to filaments

The laser plasma is one of the major contenders as a high-power source for future high-volume-manufacturing extreme ultraviolet lithography systems. Such laser–plasma sources require a target system that allows high-repetition-rate operation with low debris and manageable thermal load at the required high laser power. In this paper, we review the development of the liquid-jet target laser plasmas, from droplets to filaments, with special emphasis on its applicability for high-power extreme ultraviolet generation. We focus on two target systems, the liquid-xenon-jet and the liquid-tin-jet.