LPP EUV plasma source material target delivery system

摘要

An EUV light generation system and method is disclosed that may comprise a droplet generator producing plasma source material target droplets traveling toward the vicinity of a plasma source material target irradiation site; a drive laser; a drive laser focusing optical element having a first range of operating center wavelengths; a droplet detection radiation source having a second range of operating center wavelengths; a drive laser steering element comprising a material that is highly reflective within at least some part of the first range of wavelengths and highly transmissive within at least some part of the second range of center wavelengths; a droplet detection radiation aiming mechanism directing the droplet detection radiation through the drive laser steering element and the lens to focus at a selected droplet detection position intermediate the droplet generator and the irradiation site. The apparatus and method may further comprise a droplet detection mechanism that may comprise a droplet detection radiation detector positioned to detect droplet detection radiation reflected from a plasma source material droplet.