Emissive properties of xenon ions from a laser-produced plasma in the 100-140 Å spectral range:: Atomic-physics analysis of the experimental data

In order to design extreme ultraviolet (EUV) sources for nanolithography, xenon EUV emission has been experimentally studied in a plasma generated by the interaction of a high-power laser with a droplet jet. A theoretical model assuming that the resulting plasma is optically thick allows one to find the distribution of the relevant ions and transitions involved in the emission process. Atomic physics compigations are performed using the HULLAC code to give a detailed account of the transitions involved. The importance of 4p-4d, 4d-4f, and 4d-5p transitions is stressed, as well as the need for configuration-interaction treatment of the Deltan = 0 transitions. Comparisons of a modeled local thermodynamical equilibrium spectrum with experiment provides qualitative agreement and permits an estimate of the plasma temperature, density, and dimensions. (C) 2003 American Institute of Physics.