Multilayer Coated Reflective Optics for Extreme Uv Lithography

In this paper we present normal incidence reflectivity measurements of EUV reflective multilayer coatings for lambda = 13-14 nm, the wavelength of interest for EUV projection lithography. The multilayer coatings are produced by e-beam evaporation in combination with ion-bombardment of the layers and by magnetron sputtering. These techniques are used for coating the mirrors of our Schwarzschild telescope. We show measurements of absolute EUV reflectivity and homogeneity of the layer thickness over the mirrors. Furthermore we discuss the matching of the centre wavelength of the reflectivity curves for each of the components of our projection system.