Design,Simulation And Process Research Of Three-Axis Capacity Micro Accelerometer Based On SOI

Miniaturization is currently the important development direction of science and technology,and Micro-system(Micro-Electro-Mechanical System,MEMS)is one of the key technologies in the implementation and using of miniaturization.With its miniaturization,functional diversification,mass production and multidisciplinary cross,MEMS device has got attention and research by many countries,and we have seen considerable progress.The development of SOI technology makes the compatibility between MEMS and integrated circuit greatly increased,and further promotes the development of MEMS.As one of the important direction in MEMS research,micro accelerometer is also rapidly developed,and furthermore,the micro accelerometer based on SOI is an important development direction of future inertial measurement and guidance.Combined with the research background and development status of micro accelerometer,and after the comparison of the types and features of micro accelerometer,we choose the three-axis capacity micro accelerometer based on SOI as the research object.MEMS technology is inseparable from the integrated circuit technology,and this topic will use the integrated circuit technology such as oxidation,photolithography,physical vapor deposition technology,etc.MEMS micro machining technology consists of body micro processing technology,surface micro machining technology and special micro processing.After analyzing and researching on the working principle of the micro accelerometer,combined with the existing process conditions in the laboratory,this article independently researches and designs a kind of single mass block three-axis capacity micro accelerometer based on SOI.The support beam is composed of four groups of central symmetry serpentine beam,and it has the characteristics of high sensitivity,large range.Sensitive mass consists of block with damping hole and movable comb.The model of the micro accelerometer is established and finite element simulated in Ansys14.0,including static analysis and dynamics simulation.Through static simulation,we select 20 microns as the device thickness,and we obtained the displacement sensitivity and capacitance sensitivity of the micro accelerometer in three axial.At the same time,the micro accelerometer has good linearity with in 0g-100 g,and it's range is set as 2000 g.After dynamic simulation,we got resonant frequency and vibration shape in three axial.Micro accelerometer manufacturing process is studied under the existing conditions in the laboratory;we conducted oxidation process,metal vapor deposition process,the lithography process and dry process,silicon dioxide corrosion process,Al corrosion and stripping process of Cr technology research.Then,the processing parameters of each step were determined,and also,the process according with requirements is conformed.