MESA+ University of Twente
Industrial focus group XUV Optics


M2i research project


Project number



In situ monitoring of contamination layers on EUV optics at Angstrom resolution




2007 - 2011

Project leader

Prof. dr. F. Bijkerk (

Daily supervisor

Drs. E. Louis


J. Chen, M.Sc.

Cost estimate

M€ 0.78

Industrial partner


Aim of the project

This project aims at developing the physics and methodology of Extreme UV optics surface contamination monitoring. The goal is to be able to determine contaminants at sensitivity levels to be expected for EUV lithographic wafer scanners operating at high-volume production by the year 2009 and later. In the current absence of any directly applicable method in such scanners, an in-depth study on the various options is to be made. This will be done in parallel to on-going activities on capping layer development (at FOM) and contamination studies using capped multilayers and prototype EUV sources (in an ASML working group on contamination). Starting from the identification of the main contamination and degradation processes in these parallel activities, an adequate monitoring method of projection and illuminator optics will be developed. The final purpose is to arrive at a functional experimental model (FuMo) with the desired sensitivity and analysis power, suitable for surface oxidation depths and carbon layers of typically a fraction of a nanometer, under the boundary condition of potential applicability in EUVL scanners.

surface contamination mechanisms of oxidation and carbon growth