Spectral characterization of solid-state laser-driven plasma sources of EUV light
In this thesis, the fundamental limits of converting laser radiation via tin plasmas into EUV light in a 2% bandwidth around 13.5nm, relevant to nanolithographic applications, are experimentally investigated. In particular, plasma generation using near- to mid-infrared lasers is studied. This laser wavelength region, in combination with available energy-efficient solid-state laser technology, shows promising opportunities to achieve high plasma-brightness in combination with high overall efficiencies of converting electrical power to useful EUV radiation. In terms of light source optimization, we have investigated the effects of varying target morphologies and laser irradiation parameters, e.g., laser wavelength, laser intensity, and beam spot size on key experimental observables such as EUV spectra, the conversion efficiency of laser energy into industrially useful 13.5nm light (CE), the purity of the spectral emission (SP) and the plasma’s optical depth.