Heat load problems in deep X-ray lithography

A 3D mathematical model of a complete Deep X-Ray Lithography scanning unit based on the Finite Element Method (FEM) was developed to analyse the replication errors induced by the thermoelastic deformations occurring under irradiation. Different thermal and mechanical constraint conditions were considered in order to evaluate the maximum displacements of the irradiated mask area. The obtained results show that, to evaluate the replication errors, the support ring and its mechanical fittings have to be carefully considered in the model. It is observed that the absolute position error and the blur error and the error induced by the thermal expansion of the mask are both position dependent.