Behavior analysis of a 3-axis detection push-pull piezoresistive MEMS accelerometer

This paper reports a new concept of a 3-axis accelerometer design along with proposed fabrication steps and a circuit readout configuration. In order to achieve a better performance in terms of induced output, the study focuses on the optimization of the structure dimensions and the optimal piezoresistor´s location. The proposed model will be analyzed using Finite Element Modeling (FEM) to fully investigate the stress field in the structure based on the seismic mass movement and dimensions of attachment arms. Using Finite Element Analysis results, the push-pull operation mode has been confirmed. Maximum stress magnitude with an appropriate profile has been studied in terms of various key geometric parameters. Under an acceleration of 100g, symmetric stress magnitude profile with an approximate value of 3MPa, has been detected. This paper also discusses the structure of the built-in network of the piezoresistive Wheatstone bridge circuit and its position. We also show a flip-chip process flow for the ongoing fabrication of a polymer based accelerometer prototype.