Radiation source and lithographic apparatus

摘要

A radiation source is configured to generate extreme ultraviolet radiation. The radiation source includes a droplet generator constructed and arranged to generate fuel droplets, a heater constructed and arranged to heat the fuel droplets following generation of the fuel droplets by the droplet generator, and reduce the mass of fuel present in the fuel droplets and/or reduce the density of the fuel droplets, and a radiation emitter constructed and arranged to direct radiation onto the fuel droplets that have been heated by the heater to generate the extreme ultraviolet radiation.