Fraunhofer Institute for Applied Optics and Precision Engineering IOFSemiconductor lithography is currently boosting the optimization in the deep UV region (DUV) to its very limits. In terms of scattering analysis, this implies the sensitive and efficient characterization of optical components extending from supersmooth substrates to nanostructured thin films. The DUOSTaR technique with its various operation modi is the only system worldwide to comply with these requirements.