Radio-frequency-preionized xenon z-pinch source for extreme ultraviolet lithography

Intense amplified spontaneous emission is generated in generally axial directions in a recombining uniform Z pinch. This effect allows the generation of highly efficient soft x-ray beams, including the intense xenon-band emission at 134 Angstrom, of interest for extreme ultraviolet lithography. We discuss the characteristics of this source, including optimization of the xenon-helium mix and measurements of source size, brightness, and positional and amplitude stability. The issues involved in increasing power to the lithography class by an increase in the repetition rate are discussed. The life and operating costs of a lithography source are considered. (C) 1998 Optical Society of America.