Multilayer substrates are of great importance for direct write applica
tions. Recently, they are getting more and more importance in mask mak
ing as well, for example in the phase shift technology. In the case of
direct writing, the substrate consists of various layers of different
materials while for mask fabrication, the mask plate consists of at l
east two different layers, e.g. Cr on glass. A new method for the calc
ulation of energy deposition due to e-beam exposure in thin resist fil
ms over composite substrates is presented. The method is based on the
solution of the Boltzmann transport equation and has proven to be very
fast compared to Monte Carlo method, and its accuracy has been shown
by successful comparison with experimental obtained results. The metho
d is incorporated in a complete e-beam lithography simulator.