A New Micromachining Technique with (111) Silicon

A new micromachining technology using (111)-oriented silicon is developed. This technology allows advanced surface micromachining with the advantages of using bulk silicon. It utilizes reactive ion etching (RIE) for patterning of microstructures to be released from the substrate, followed by aqueous alkaline etching of bulk silicon under the patterns to release the microstructures. The release etch utilize the high etch selectivity of {111} planes to {100} and {110} planes, and therefore, large plates can be released without additional etch holes, and very smooth and clear undersurfaces and substrate support surfaces can be micromachined.