Combining microstereolithography and thick resist UV lithography for 3D microfabrication

A new approach for the realization of true 3D polymer structures is presented in this paper. It consists in adding, in a post-processing microstereolithography step, 3D polymer microstructures on top of a micropart patterned by means of planar processes such as thin films, bulk silicon etching or high aspect ratio structuration (LIGA, RIE, thick resist). This way, some shape limitations of the planar technologies can be the new functional applications. Direct processing of microstereolithography on predefined structures prevents manipulations which are associated with microassembly of separated parts. To demonstrate this combination of microstructuration processes, an example showing a conical axle added by microstereolithography on a SU-8 piece of gearing is presented.