Squeeze-Film Damping in Perforated Microstructures: Modeling, Simulation and Pressure-Dependent Experimental Validation

The reliable estimation of squeeze-film damping (SQFD) is a prerequisite for the design of many microelectromechanical systems (MEMS). The proper operation of several MEMS devices (e.g. accelerometers) often depends crucially on the damping forces, i.e. the pressure level within the package. However, the simulation of SQFD is a challenging task since it is, by its nature, a distributed effect that cannot be simply lumped into an analytical model. Moreover, due to the small geometrical dimensions and especially at low pressure, gas rarefaction becomes eminent, making the modeling of SQFD on the basis of classical continuum theory a delicate issue. Commonly, the compact models presented by Bao [1] and Veijola [2] are used for the calculation of SQFD in MEMS, even though a systematic experimental validation of these models was not available for several years. Only recently, De Pasquale [3] presented a first experimental evaluation of the model by Veijola, but at normal pressure only. He showed that the relative error of the model by Veijola exceeds for some of the investigated devices a threshold of 63 %