A static technique for the electro-mechanical characterization of MEMS devices for RF and microwave applications

An approach for measuring force-dependent properties of microscopic structures commonly found in MEMS has been developed. The system has the capability of measuring forces and deflections of the order of micro-newtons and micro-meters, respectively. By implementing a visual inspection system, force is applied to localized areas on a beam, and the resulting force-deflection characteristic can be obtained. From this beam stiffness and effective elastic modulus can be calculated. These results were compared to simulation, which was performed using ANSYS FEM code. In addition, by applying a known mechanical force, direct correlation to voltage and thus electrostatic force can be obtained, which also elucidates the magnitude of the electrostatic feedback effect. Characterization of other force-dependent parameters such as DC contact resistance and isolation/insertion loss at RF and microwave frequencies was obtained experimentally, from which parameters such as lumped capacitance can be extracted.