Mechanical reliability of MEMS fabricated by a special technology using standard silicon wafers

This paper presents a new process flow for the fabrication of Air gap Insulated Microstructures (AIM) with strengthened interconnection beams based on standard single crystal silicon wafers. The main focus on the new development was set on the attributes of reliability and fatigue. As a result of our investigations, the interconnection beams were identified as weakest point in the system. To improve the quality of the beams, several material stacks with well defined properties were tested in order to find a suitable material stack for the interconnection beams instead of pure aluminum. The new process flow enables the use of multi-layered beams without loosing any of the advantages of the AIM technology and also without increasing the number of masks.