Thin MEMS microphone based on package-integrated fabrication process

摘要

A thin capacitive-type MEMS acoustic sensor fabricated using a fully package-integrated process is presented. This sensor has a very slim thickness of 150 ;C;m due to the elimination of the complicated backside alignment process which requires a thickness of more than 400 ;C;m to prevent the substrate from breaking down. In addition, a structure-based equivalent circuit modelling was performed to evaluate the characteristics of the proposed microphone. The measured initial gap was 2.8 ;C;m, which resulted in an intrinsic capacitance of 0.89 pF and the natural frequency was 83 kHz. The sensor has an opencircuit sensitivity of -47.7 dBV/Pa at 1 kHz with 10.4 V. The modelled sensitivity shows good agreement with the measured sensitivity.