Research And Design Of Micro-Pressure Sensor Based On SOI Material

Currently, silicon micro-pressure sensors mostly need to be imported from abroad. The high level manufacturing process is required for the micro-pressure sensors. Low level technology is the main factor to limit the performance of silicon micro-pressure sensor. The research on the lower range silicon micro-pressure sensor is helpful to improve its technology and to promote the development of the related industries rapidly.To solve the production process problems during the fabrication of the silicon micro-pressure sensors, firstly, the advantages and disadvantages of different elastic structures are analyzed. According to the existing technology and process condition in sensor national engineering center, the island-diaphragm structure is adopted. Secondly, finite element software is used to establish the structural model of the sensor chip, the stress distribution of the chip surface is analyzed when pressured, the structural parameters of the sensor is optimized, and the structure sizes of the chip are determined. Meanwhile, the production processes of MEMS devices are designed based on the bonding technology SOI wafer materials, including the semiconductor planar process and the anisotropic etching process. Difficult problems such as the precise control of film thickness and area convex corner compensation have been paid great attention. Finally, the devices are packaged, electrostatic bonding technology is applied to the bonding between the chip and substrate, ultrasonic wire pressure welding is adopted to complete wire bonding, the solid-state isolation package structure is adopted, and the sensor chip is isolated with the external environment with the diaphragm and silicon oil.Sensor is calibrated with the gas pressure gauge. Then, the sensors are tested for three-consecutive pressure cycle in the whole range of (0~1Kpa), and least squares method have be used for data processing. The results show that the output sensitivity is greater than 60mV/KPa, nonlinearity is less than 0.1% FS, the accuracy is less than 0.5% FS. The fabricated silicon low sensors have good performance.