EUV emission from Kr and Xe capillary discharge plasmas

Abstract

Kr and Xe plasmas are very intensive emitters in the spectral range of 100-150 Å, which is relevant for a number of applications (for example microlithography). We present investigations of the extreme utraviolet (EUV) emission from a slow capillary discharge with Kr and Xe fillings. The emission of Kr ions (Kr VIII to Kr XI) within the range of 70-150 Å consists of three bands of lines of about 10 Å width with maxima at 116, 103 and 86 Å. Xe emission bands of about 15 Å width have their maxima at 136 and 115 Å (Xe IX to Xe XII). The radiation duration in this spectral range is ~150 ns for both elements. At the optimum conditions, the Kr emission at 103 Å is 2-3 times more intense than the Xe emission at 136 Å. The measured spectral energy of Kr radiation is about 0.1 J sr-1 Å-1. Experimental results are compared with numerical modellings of the dynamics and emission of the capillary discharge plasma, which enables the determination of plasma parameters and the future use of the codes as additional instruments for plasma diagnostics.