Abstract：Based on the self-similar solution of Navier-Stokes equations， properties of fast ion debris emitted from laser-produced mass-limited plasma had been theoretically investigated for an application to extreme ultraviolet lithography (EUVL). Using numerical technology， the average ionization degree， the plasma plume size， the expansion velocity and the ion kinetic energy evolutions for three values of adiabatic exponent γ＝1.67， 1.3 and 1.1 were presented. The angular distribution of fast ion debris fluxes and erosion rates due to sputtering yield for Ru， Mo， and Si under tin ion bombardment were calculated. It was found that angle dependence of the erosion rate due to sputtering yields Y of Si and Mo with Sn showed cos3θ profiles. The formation of low ionization degree and minimum-mass plasma for EUV sources are expected to result in a significant increase in the collector mirror lifetime.
2017, Vol. 51 
