A method for realizing robust micro-scale electromagnetic actuators for high current density applications

This paper presents a method for manufacturing MEMS ring resonators with high current carrying capacity from a single silicon-on-insulator (SOI) wafer. Ring resonators working with electromagnetic actuation scheme require large amplitudes to realize high sensitivity such as in inertial devices. Driving the ring resonator for sustained large amplitude motion often requires high current in the thin metal tracks running over the ring structure. High current results in increased current densities that cause electromigration leading to higher resistance, reliability degradation and eventual failure. The reported method describes a novel technique to increase the current handling capability with the same metal features by introducing a conformal electromigration suppression layer. The experimental results show that the current carrying capacity of the metal lines improves by at least 300%. The proposed technique is implemented in realizing an electromagnetic induction-based ring gyroscope. The electrical and mechanical responses of the ring resonator are presented as well.