Pinch-plasma radiation source for extreme-ultraviolet lithography with a kilohertz repetition frequency

An extreme-ultraviolet radiation source based on a xenon pinch plasma is di scussed with respect to the demands on a radiation source for extreme-ultra violet lithography. Operation of the discharge in a self-igniting-plasma mo de and omitting a switch permits a very effective and low-inductive couplin g of the electrically stored energy to the electrode system. The xenon plas ma exhibits broadband emission characteristics that offer radiation near 11 and 13 nm. Both wavelengths are useful in combination with beryllium- and silicon-based multilayer mirrors. The plasma emits approximately 74 mW/sr a t 11.5 nm and 40 mW/sr at 13.5 nm in a bandwidth of 2% when operated at a r epetition frequency of 120 Hz. The source size is less than 500 mu m in dia meter (FWHM) when viewed from the axial direction. The pulse-to-pulse stabi lity is better than 3.6%. First results with a repetition rate of as much a s 6 kHz promise the possibility bf scaling to the required emission power f or extreme-ultraviolet lithography. (C) 2000 Optical Society of America OCI S codes: 220.3740, 260.7200, 300.6560, 350.5400.