Micro-optic fabrication using one-level gray-tone lithography

This paper reports on a methodology to fabricate arbitrarily shaped structures using technologies common to standard IC manufacturing processes. Particular emphasis is placed on the design and use of half-tone transmission masks for the lithography step required in the fabrication of mechanical, optical or electronic components. The algorithms to transfer an initial height profile into a design representation in the common GDSII data format are discussed. This set of data could be used directly by a commercial mask shop. The major amount of data for a reticle layout is reduced significantly by a linear working data compaction algorithm. The nonlinear influences of the different process steps on the transfer function are regarded. The specific parameters for the mask making and resist processes are determined. Several components like shaped gratings or lenses are realized in resist up to 10 mu m thick. In the field of pattern transfer into a substrate material like silicon, a dry etchin g process is evaluated.