Results of optimization of an excimer laser-induced plasma x-ray sourc
e for projection lithography in the range lambda=13-15 nm are reported
. A conversion efficiency of >0.7% in 2% BW has been achieved with hig
h-Z target materials. Two methods of reducing contamination of optical
elements by target debris have been tested: usage of a thin target la
yer (for Ta 1 mu m was found to be optimal) and of a heavy buffer gas.
The effect of the use of Ta-tape target and Kr buffer gas has been me
asured by determining the reflectivity of a Mo-Si multilayer sample af
ter 10(5) shots.