INTENSE PLASMA DISCHARGE SOURCE AT 13.5 NM FOR EXTREME-ULTRAVIOLET LITHOGRAPHY

We measured an emission of 6 mJ/pulse at 13.5 nm produced by the Li2Lyman-cr transition excited by a fast capillary discharge, using a lit hium hydride capillary. 75% of the energy emanated from a spot size of 0.6 mm. The emission is narrow band and would thus be useful in extre me-ultraviolet lithography imaging systems that use Mo:Si multilayer m irrors. The output within the bandwidth of Mo:Si mirrors was comparabl e with that of a laser-produced plasma (LPP), and the wallplug efficie ncy of 0.1% was nearly an order of magnitude better than that of a LPP . (C) 1997 Optical Society of America