Extreme-ultraviolet light source for lithography based on an expanding jet of dense xenon plasma supported by microwaves

We discuss a concept of a point-like source of the extreme ultraviolet (EUV) light based on a non-equilibrium microwave discharge in expanding jet of dense xenon plasma with multiply charged ions. A conversion efficiency of microwave radiation to EUV light is calculated, and physical constraints, and opportunities for future devices are considered. Special attention is given to trapping of spontaneous line emission inside a radiating plasma spot that significantly influences the efficiency of EUV light source.