Adhesion release and yield enhancement of microstructures using pulsed Lorentz forces

Adhesion of microstructures is an important failure mechanism in surface-micromachined devices. In this paper, a simple and effective method for releasing pinned microstructures is presented. The method uses the Lorentz force due to the interaction of a current with an external magnetic field to generate an upward force that frees the microstructures. The static and transient behavior of beams under the Lorentz force is examined. Critical values of current and pulse durations needed to release the microstructures are determined and verified with experimental data. Using this technique, previously pinned beams and rectangular plates have been released. The release technique is suitable for mass production environments since it is easily applied during the electrical testing of the device, thereby increasing the manufacturing yield.