A thin film molding process was developed to enable the fabrication of mono
lithic micromechanical structures with built-in electrical isolation and em
bedded interconnects. High-aspect-ratio composite structures were created f
rom undoped polysilicon, low stress nitride and doped polysilicon, in a dua
l micromolding process. These monolithic electro-mechanical microstructures
are more resistant to thermal effects and misalignment errors compared to
microsystems assembled from discrete elements. In addition, the microstruct
ures are molded in a re-usable mold providing an economical advantage. A gi
mballed electrostatic microactuator was successfully fabricated using this
process. Electrical isolation was achieved with a combination of low stress
nitride and undoped polycrystalline silicon. Various isolation geometries
were investigated. Current leakages of less than 1 nA at 30 V were measured
for isolation structures 40 mum long and 80 mum tall.