EUV-source modeling with account of detailed level kinetics included in-line into gasdynamic calculations
The model of nonstationary non-equilibrium radiative plasma with accounting for level kinetics and radiative transport in spectral lines is constructed. The modeling of spherical target explosion and emmision as a result of laser pulse is carried out. Numerical calculation of two-temperature 1D Lagrangian equations of gasdynamics is realized. Radiation field and level kinetics are accounted self-consistently by using two different approaches: using interpolation between
pre-calculated tables of spectral parameters and with account of detailed level kinetics included in-line into gasdynamic calculations. The efficiency of extreme ultraviolet source based on lithium and tin laser plasma is estimated. The results have a significant value for EUV-lithography, which is used in microchip production.
Obtained efficiency of EUV-source at optimal parameters of laser pulse is ~ 1% for lithium and ~ 5% for tin, that is close to experimental data.