A multi-kilohertz pinch plasma radiation source for extreme ultraviolet lithography

A pinch plasma source in the extreme ultraviolet is presented where the spe cial design of the electrodes leads to advantages concerning low erosive op eration and an effective coupling of the electrically stored energy to the electrode system. Most promising results of the source parameters with resp ect to the demands for extreme ultraviolet lithography are achieved when op erating with xenon. Intense emission around 11 nm and 13 nm is observed. Th e plasma column has a diameter of less than 500 mum when viewed from the ax ial direction. The electrode design allows for an accessible solid angle of around pi sr. The shot-to-shot stability is better than 4% (rms). A maximu m output of 0.8 mJ/(sr 2% bw) at 13.5 mn has been observed with an input pu lse energy of 2 J. Operation at a repetition rate of 1 kHz and an electrica l input power of 2 kW has been demonstrated with an average emitted power o f around 0.3 W/(sr 2% bw). Approaches of power scaling into the range which is desired for EUVL will be discussed. (C) 2001 Elsevier Science B.V. All rights reserved.