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 wavelen gth of interest for EUV projection lithography. The multilayer coating s are produced by e-beam evaporation in combination with ion-bombardme nt of the layers and by magnetron sputtering. These techniques are use d for coating the mirrors of our Schwarzschild telescope. We show meas urements of absolute EUV reflectivity and homogeneity of the layer thi ckness over the mirrors. Furthermore we discuss the matching of the ce ntre wavelength of the reflectivity curves for each of the components of our projection system.