3D microfabrication by combining microstereolithography and thick resist UV lithography

A new approach for the realization of true 3D polymer structures is present ed in this paper. It consists in adding, in a post-processing microstereoli thography step, 3D polymer microstructures on top of a micropart patterned by means of planar processes such as thin films, bulk silicon etching or hi gh aspect ratio structuration (LIGA, RIE, thick resist). In this way, some shape limitations of the planar technologies can be overcome for new functi onal applications. Moreover, the direct processing of microstereolithograph y on predefined structures eliminates manipulations which are associated wi th micro-assembly of separated parts. To demonstrate this combination of mi crostructuration processes, an example showing a conical axle added by micr ostereolithography on a SU-8 piece of gearing is presented. (C) 1999 Elsevi er Science S.A. All rights reserved.