Modelling of a chip scale package on the acoustic behavior of a MEMS microphone

Micro-electro-mechanical system (MEMS) microphones have been widely used in the mobile devices in recent decades. The acoustic effects of a chip scale package on a MEMS microphone needs to be validated. Previously a lumped equivalent circuit model was adopted to analyze the acoustic frequency response of the package. However, such a theoretical model cannot predict performance at relatively high frequencies. In this paper, a distributed parameter model was proposed to simulate the acoustic behavior of the MEMS microphone package. The model illustrates how the MEMS microphone acoustic transfer function is affected by the size of sound hole, the volumes of the front and back chamber. This model also can illustrate the mechanical response of the MEMS microphone. The proposed model provided a more reliable way towards an optimized MEMS package structure.