Design And Analysis Of The Resonant MEMS Pressure Sensor

A silicon micro-resonant pressure sensor is a typical MEMS device that achieves pressure measurement by detecting changes in the natural frequency of the resonator when external pressure is applied.Its working mechanism of the device ultimately leads to better performance than the general diffusion silicon pressure sensor,and the working process is highly resistant to electrical drift,electrical noise and other circuit parameters;In addition,resonant pressure sensors are digital outputs.It is easy to match with computer components to form a high-performance microcomputer,electrical measurement and control system,high-stability micro-computer and electric measurement and control system.Thus the silicon micro-resonant pressure sensors are ideal for aerospace,industrial monitoring and medical precision measurement applications where accuracy,stability and other performance are critical.They have very high market demand in military and civilian fields at home and abroad.A silicon micro-resonant pressure sensor based on electrostatic excitation/piezores-istive detection is proposed.The device adopts the vibration mode of in-plane dynamic balance.In order to minimize the variation of the resonator height that may be generated during the operation of the designed sensor,the fixed-end structure of the resonator is optimized to ensure that the vibration system of the resonator does not interfere with the quality of the same vibration during operation,and there is no energy between the two.Coupling,which greatly enhances sensor stability.Based on the theoretical modeling of single-ended fixed-beams.The frequency formula of the resonator ‘ ? '-beam is deduced,and the corresponding relationship between axial stress and frequency variation is further analyzed.The small deformation and stress transmission of the sensitive films are also analyzed,and then the theoretical analysis of the process of electrostatic excitation and piezoresistive pickup are supplemented.The natural frequency and dynamics of the resonator was analyzed.Thereby optimizing the sensor design and determining the sensor parameters.According to the analysis and establishment of the mathematical model of the sensor,the simulation analysis and simulation verification of the sensor in the range of 0-150 kPa and full-scale of 1.5 times are carried out by MEMS finite element simulation software.The initial frequency is24.01 kHz,and the sensor sensitivity is 18Hz/kPa.A micro-machining process based on a commercially available silicon-on-insulatorwafer has been provided for the resonant pressure sensor.Research and compare several micro-machining processes,using silicon-silicon bonding technology to realize vacuum packaging of pressure sensors,and using nano getter and double-walled package cap structure design to further improve package life.Finally the sensor and the circuit chip are 3D mixed and integrated and packaged through the TSV through-hole technology,and then the core layout is analyzed and designed.