  We present rigorous simulations of EUV masks with technological imperfections
like side-wall angles and corner roundings. We perform an optimization of two
different geometrical parameters in order to fit the numerical results to
results obtained from experimental scatterometry measurements. For the
numerical simulations we use an adaptive finite element approach on irregular
meshes. This gives us the opportunity to model geometrical structures
accurately. Moreover we comment on the use of domain decomposition techniques
for EUV mask simulations. Geometric mask parameters have a great influence on
the diffraction pattern. We show that using accurate simulation tools it is
possible to deduce the relevant geometrical parameters of EUV masks from
scatterometry measurements.
  This work results from a collaboration between Advanced Mask Technology
Center (AMTC, mask fabrication), Physikalisch-Technische Bundesanstalt (PTB,
scatterometry), Zuse Institute Berlin (ZIB), and JCMwave (numerical
simulation).
