Multi-Scale Modeling of Shock-Induced Failure of Polysilicon MEMS

We investigate the shock-induced stress state and possible failure mechanisms in polysilicon MEMS sensors. In case of accidental drop events, we aim at highlighting the links between drop features, like drop height and impact angles, and the location of the failing detail of the device. Taking into account the small inertial contribution of the sensor to the whole package dynamics, we adopt a decoupled multi-scale numerical approach, where macro-scale analyses (at die length-scale) are used to define the acceleration records to be adopted as loading in meso-scale (at sensor length-scale) simulations. We show that a commonly adopted indicator to assess drop severity is not able to take in due account the details of the impact event and possible very localized failures at the sensor level.