Accuracy analysis of a stand-alone EUV spectrometer for the characterization of ultrathin films and nanoscale gratings

In this contribution the accuracy of a stand-alone EUV spectrometer utilizing radiation in the range from 7 nm to 17 nm is analyzed. The setup is used to determine optical constants and dimensional characteristics of samples, e.g. ultrathin films and nanoscale gratings, reconstructed from measurements of their broadband EUV reflectance at grazing incidence angles. A high accuracy of these measurements is crucial for a reliable characterization of samples. We present an overview on the sources of uncertainties in the setup and their influence onto the reconstructed sample parameters. A variety of improvements to the setup is presented that enhance its accuracy.