Development of surface micromachining techniques compatible with on-chip electronics

Abstract

Silicon has long been known to have excellent mechanical properties although the full potential of the material was not realized until micromachining techniques enabled the fabrication of true mechanical structures. The first types of structure were fabricated using bulk micromachining techniques, where the silicon wafer is etched to leave free-standing mechanical structures. More recently surface micromachining techniques have received considerable attention. In this case the mechanical structures are fabricated in thin films deposited on the silicon wafer surface. This development has yielded structures considerably smaller than those fabricated in bulk micromachining. In this paper the development of surface micromachining techniques is reviewed. This includes the modifications required to achieve compatibility with standard electronic circuitry.