Abstract:
A radiation system to generate a radiation emitting plasma, the radiation system include a fuel emitter to provide a fuel target at a plasma formation region, a first laser arranged to provide a first laser beam at the plasma formation region incident on the fuel target to generate a radiation emitting plasma, an imaging device arranged to obtain a first image of the radiation emitting plasma at the plasma formation region, the first image indicating at least one image property of the radiation emitting plasma, and a controller. The controller is arranged to receive the first image, and to generate at least one instruction based on the at least one image property of the radiation emitting plasma to modify operation of at least one component of the radiation system to reduce a detrimental effect of debris.
Abstract:
A radiation source, e.g. for EUV for use in a lithographic apparatus, generates radiation by illuminating droplets of fuel with first radiation to form a plasma and collects second radiation omitted by the plasma using a collector (CO). The collector has an aperture and the fuel passes along a vertical trajectory through that aperture before being irradiated by the first radiation. In an embodiment the first radiation is directed along a beam, the final part of which is coincident with the final part of the trajectory of the fuel droplets. In an embodiment a gas flow is arranged coincident with the fuel trajectory and/or the beam of first radiation.