Gasdynamically-controlled droplets as the target in a laser-plasma extreme ultraviolet light source

摘要

A target material delivery system in the form of a nozzle (50) for an EUV radiation source (10). The nozzle (50) includes a target material supply line (66) having an orifice (68) through which droplets (76) of a liquid target material (64) are emitted, where the droplets (76) have a predetermined size, speed and spacing therebetween. The droplets (76) are mixed with a carrier gas (74) in a mixing chamber (54) enclosing the target material chamber (66) and the mixture of the droplets (76) and the carrier gas (74) enter a drift tube (56) from the mixing chamber (54). The droplets (76) are emitted into an accelerator chamber (124) from the drift tube (56) where the speed of the droplets (76) is increased to control the spacing therebetween. A vapor extractor (90) can be mounted to the accelerator chamber (124) or the drift tube (56) to remove the carrier gas (74) and target material vapor, which would otherwise adversely affect the EUV radiation generation.