Lifetime investigations of directly wafer-bonded samples under static and cyclic loading

Strength and fatigue tests were performed to investigate the reliability properties of Si wafer-bonded samples exposed to static or cyclic mechanical loading. A distinct strength decrease with increasing loading duration or load cycle number, respectively was found limiting the lifetime of mechanically stressed wafer bonded components. As a consequence, loaded wafer-bonded sensors and actuators may suddenly fail during application. Appropriate fracture mechanical approaches can be applied to predict the lifetime behavior for a given loading situation and, therefore, to provide a high reliability of micromechanical devices.