Reliability investigations on stacked chip on MEMS

Increasing functionality in vehicles especially with respect to electromobility is demanding a decrease of energy consumption of numerous board systems. Clustering and miniaturization of sensor applications on the one hand are enabling new features and on the other they are minimizing energy needs for their operation. For modern vehicle driving stability or navigation systems e.g., the SCoM (stacked chip on MEMS) approach will provide the technology enabling shrinking of the sensors size on a high integration level by bringing intelligence directly to the sensor. To cope with the reliability requirements, restrictive qualification and zero defect strategies have been established by the automotive industry. Hence, introduction of innovative technologies in automotive applications must be accompanied by the demonstration of their reliability and safety. It is the goal of the RESTLES [1] project to eliminate parasitic sensor effects caused by process tolerances, intrinsic material stress, thermal mismatch, temperature and aging phenomena by transferring dedicated compensation models into the sensor and circuit design. To evaluate influences of thermo-mechanical stresses and strains, extensive simulations of the package behavior and non-destructive evaluation have been performed.