process for conversion of laser radiation in x-rays, particularly euv radiation by means of a the laser produced plasma

摘要

Broadband light sources in the extreme ultraviolet (EUV) and weak X-ray range can be realized by the interaction of pulsed lasers with matter. Radiation-emitting plasmas are produced when laser pulses impact with a sufficient amount of intensity against solid, liquid or gaseous materials. In order to realize emissions in the hard X-ray range, lasers must be used which have high peak intensities, that is, they have pulse durations of less than one nanosecond. The aim of the invention is to increase the efficiency of the conversion of laser radiation into X-radiation, in particular, into EUV radiation. To this end, the invention provides that amplitude-modulated or phase-modulated sub-nanosecond pulses are irradiated onto the solid, liquid or gaseous material in order to generate a plasma having a high radiation conversion efficiency. The pulse modulation ensues according to the intensity of the X-radiation emitted by the plasma. The invention is used, for example, in electron-beam lithography for producing microelectronic semiconductor components.