Silicon Fusion Bonding and Deep Reactive Ion Etching a New Technology for Microstructures

It has become common to categorize silicon micromachining processes in terms of "bulk" and "surface" techniques. "Bulk" micro-machining generally refers to structures which have been formed by deep anisotropic etching. In these devices, a portion of the substrate itself is usually an active mechanical element of the micromechanical device. "Surface" micro-machining generally refers to structures which have been formed from thin film layers deposited or grown on the surface of the silicon substrate. New developments in deep reactive ion etching technology (DRIE), combined with silicon fusion bonding (SFB), have made it possible, for the first time, to span nearly the entire range of microstructure thicknesses between surface and bulk micromachining, using only single crystal silicon. This presentation will explain the processes and technologies which make this possible, and will describe some structures and devices which have been demonstrated using this new process technology.