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 put on the design and use of halftone transmission masks for the lithography step required in the fabrication process of mechanical, optical or electronic components. The algorithms to transfer an initial height profile into a design representation in the common data format GDSII are discussed. This set of data could be used directly by a commercial mask shop. The great data amount of 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 the resist process are determined. Several components like shaped gratings or lenses are realized in resist up to 10 mu m thick. In the field of transfering the pattern into a substrate material like silicon, a dry etching process is evaluated.