Efficient Generation of Extreme Ultraviolet Light From Nd:YAG-Driven Microdroplet-Tin Plasma

Plasmas produced from microdroplets of liquid tin provide light at an extreme ultraviolet (EUV) wavelength of 13.5 nm, for state-of-the-art nanolithography that will enable the continuation of Moore's law in shrinking transistors. Currently CO₂ gas lasers are used to drive such plasma; transitioning to modern solid-state lasers would have significant advantages, if the efficiency of converting laser energy into 13.5-nm radiation were sufficiently competitive. This study quantifies the radiation efficiency of solid-state-laser-driven tin plasma. High conversion efficiencies are obtained, and paths toward higher efficiencies using 1-μm solid-state lasers are identified.