Strength assessment of wafer-bonded micromechanical components using the micro-chevron test

In this paper, the testing principles and different application examples of the Micro-Chevron-Test (MC) are discussed. The chevron pattern required for testing can be fabricated either by wet or reactive ion etching. It is shown that the test has a higher accuracy than common tensile or bend strength tests, allowing also the determination of fracture mechanic parameters, such as fracture toughness. In addition one can characterize the spatial strength distributions for the bonded wafer in order to determine the sources of production yield problems. Furthermore, the sample size can be reduced to the typical size of micro electro mechanical systems (MEMS) devices allowing the MC sample fabrication to be integrated into the MEMS fabrication process. Therefore, the test can be applied as an effective, reliable and precise tool for wafer bond process development and for quality control during the fabrication of micromechanical devices.