Reliability Aspects of Microsystems for Automotive Applications

The implementation of microsystems in automotive applications is certainly one of the driving forces for the success of MEMS as an industrial technology on mass production level. In many cases, automotive systems based on microsensors are critical to safety. Consequently, microsystems have to assure an accurate, reliable, and failsafe operation during the entire lifetime of the vehicle. Since, the car represents a harsh environment for electronic or mechanical systems and components, reliability issues of MEMS have moved more and more into the focus of research and development. In particular, reliability aspects related to packaging and assembly have become a key issue in lifetime investigations. The packaging of microsystems comprises a variety of materials and material combinations, that directly affect the stability of MEMS components. Therefore, sophisticated characterization methods are needed to extract the reliability‐relevant material parameters. This paper gives an introduction into investigations of the stability assessment of glass frit bonding as well as new bonding technologies based on metallic sealing of MEMS devices. The reliability of hermetically encapsulated microsensors is a prerequisite in safety‐relevant applications for the automotive market and for consumer applications. The hermeticity and protection of the sensor structure against environmental influences are provided by a cap that is bonded to the substrate utilizing glass frit or metallic bonding technologies. The mechanical strength of these two types of bonding layers is discussed in the paper.