NEW KRF AND ARF EXCIMER-LASER FOR ADVANCED DUV LITHOGRAPHY

Excimer laser steppers are used since 1988 and performance has improved significantly over the years. To meet the demands on output power and spectral purity of advanced deep ultraviolet (DUV) optical lithography tools, a new laser cavity and line narrowing module has been designed. Combination of this modules allows line narrowed operation of the excimer laser with high repetition rate at low cost of operation. The unique resonator concept was optimized to meet the requirements on spectral purity and to maximize lasertube lifetime. The developed lasertube, NovaTube(TM), is the result of many years of extensive test and material research. For the first time a KrF laser was successfully operated in a quasi sealed-off mode for more than 1 billion pulses.