Spectroscopic ellipsometry has long been recognized as the technique of choice to characterize thin films and multilayers. Instrumentation for the next generation of VUV lithography at 157 nm requires special optical setup since O-2 and H2O are extremely absorbing below 190 nm. A new system has been developed which works into a purged glove box to reduce the oxygen and water contamination in the part per million range. Ellipsometric and photometric measurements vs. wavelength and angle of incidence can be performed. Grazing X-ray option has been added on the same instrument to provide a better picture of the analyzed samples. This paper presents in detail the new system with its two measurement methods, and includes experimental results gate dielectrics layers and high k dielectrics. (C) 2003 Elsevier B.V. All rights reserved.