Diagnosis of parametric defects in dual axis IC accelerometers

Microelectromechanical systems fabrication and packaging may induce parametric defects which have to be efficiently diagnosed to improve fabrication yield and device reliability. In this work, the possibilities of diagnosing single parametric defects in dual axis IC accelerometers are explored. The proposed method is a reuse of a mixed-signal diagnosis strategy based on Lissajous compositions. It consists of a dynamic correlation of the two orthogonal output signals of the device. This leads to a Lissajous trace which is able to manifest parametric deviations. Several device parameters have been studied and characterized under different deviation levels. The definition of a metric and the evaluation of its diagnosis efficiency is used to optimize the diagnosis procedure against noisy measurements. The method has been experimentally applied to diagnose the misalignment degree in a commercial dual axis accelerometer. The Lissajous characterization of the defect is illustrated and experimental results are reported. Misalignment diagnosis results show the viability of the proposal.