3D structures for micro-system technology using proximity lithography

A new surface micro-machining technology called 3D UV-microforming was used to fabricate three-dimensional components on silicon substrates. The procedure consists of an advanced resist preparation process, a UV lithographic step, resist development, a galvanic molding procedure for filling up the resist patterns, and finally stripping and cleaning to finish the structures. With exposure by UV proximity aligners and immersion development, thick resist layers could be patterned in a single shot on pre-processed silicon wafers. High aspect ratios and steep edges were fabricated (Fig. 1). The resist patterns were molded using pulse or DC electroplating. Intermediate plating bases were deposited on resist to achieve bridge and cantilever structures. Magnetically driven micro components, such as reeds and membranes for valves, were fabricated to demonstrate the new technique.