Strength and Reliability Properties of Eutectic Bonded MEMS Structures

Inhalt:
Hermetic wafer level encapsulation is of utmost importance to ensure high reliability and lifetime of Micro-Electro-Mechanical Systems (MEMS). This paper presents an investigation of the stability assessment of AlGe eutectic bonding technology for sealing of MEMS devices. For this purpose, an approach based on fracture mechanics is developed which can be applied during the development of bonding technologies. Fracture toughness measurements are performed with the first application of the Micro Chevron (MC) Test upon eutectic bonded samples. Using a 3D finite element (FE) model, the critical energy release rate GIC for Mode I is determined. Fractured surfaces of the bonded samples exhibit arbitrary crack paths, which in general indicate cohesive failure through the AlGe eutectic film.