Mechanical reliability tests for bonded wafers

The fabrication of micromechanical components, such as acceleration sensors, pressure sensors, valves or micropumps, requires special joining technologies, like direct or anodic wafer bonding. An essential prerequisite for practical applications is a sufficient mechanical strength and reliability of the bonded interfaces. Therefore, appropriate testing techniques are required that can be applied to quality control, component design and failure analysis. Strength testing and FEM modelling have been employed to examine three types (tensile testing, DCB-test and test of chevron notched specimens) of tests. The investigations showed that strength testing of wafer bonded samples requires a careful assessment of the applied testing techniques with respect to the testing conditions, loading, sample geometry and analysis of the results.