Hinge Chain Wideband High Range Micro-accelerometer

With the development of science and technology, Silicon micromachined accelerometers have been widely used in the fields of sensing of automobile crashes, control of vehicle dynamics, and high-g-force impact assessment. The vital MEMS accelerometers made by the microelectronics and micromachining technology have many advantages over the conventional ones and have been a hot choice for research and application. The high-g micromachined piezoresistive accelerometers usually need wider bandwidth than low range piezoresistive accelerometers. For example, the highest load acceleration of these sensors can be as high as tens of thousands of gravities, the sensitivity is 0.2～0.4 μV/g, and the installation frequency can reach the magnitude of MHz.A new hinged micromachined piezoresistive high-g accelerometer is designed and modeled in this paper. A novel structure design can significantly increase the sensor's natural frequency while maintaining a high sensitivity, so the wave shape of shock acceleration can be truly reflected in broader bandwidth. Presented in this paper, is the design, theoretical analysis, configurations optimization, fabrication and simulation of the packaging structure of the accelerometer. In chapter 2, the mechanism of the sensor is discussed in detail. Then a simplified analytical model and a improved analytical model is established to describe the accelerometer's mechanical behaviour. Finite element modelling was also conducted to verify two analytical models and evaluate the performance of the micro-accelerometer. In the improved analysis, the effects that the mass of beam and hinge and the deformation of the mass have on the performance of the accelerometer have been taken into account. Comparison of the frequency results obtained from the improved analytical model and finite element simulation shows good agreement. Finally, the optimal selection of the geometrical parameters of the accelerometer was obtained from the analysis.In chapter 3, layout design of the sensors' chip and the process was elaborated.In chapter 4, the finite element analysis of the packaging structure for the accelerometer, including the modal analysis, static analysis of the effect of elastic modulus of the potting resin in the package on the performance of the accelerometers were conducted.