Characterizing resists and films with VUV spectroscopic ellipsometry

Spectroscopic ellipsometry has been the technique of choice to characterize thin films and multilayers in semiconductor manufacturing. Extending this technology into the vacuum ultraviolet range, down to 140nm, however, for e merging 157nm optical lithography applications, requires an environment tha t avoids the absorbing effects of oxygen and water vapor below the 190nm wa velength; these must be reduced to the parts/million range. In addition, th e optical setup for VUV spectroscopic ellipsometry must put the monochromat or in the ellipsometer's polarizer arem to avoid photobleaching, and the el lipsometer must work in a rotating analyzer configuration to minimize paras itic polarizations.