Research On Design And Manufacturing Process Of MEMS High Temperature Pressure Sensor

Pressure sensors are widely used in aerospace,pressure vessels,automobiles,oil and gas pipelines,and meteorology.However,in the fields of nuclear power,metallurgy,chemical industry,engine monitoring,etc.,there are high requirements for the temperature resistance of pressure sensors.Diffused silicon pressure sensors are difficult to adapt to these high temperature working environment requirements.Therefore,high temperature pressure sensors are one of the important directions of current research.At present,high-temperature MEMS pressure sensors made of special materials such as silicon-sapphire,silicon-diamond,4H-SiC and 6H-SiC have good temperature resistance,but their manufacturing process is relatively complicated and the cost is relatively high.To this end,this paper designs a high-temperature silicon pressure sensor with a differential structure based on metal strain resistance.The principle,simulation theory and manufacturing process of the sensor are described.The sensor has less MEMS process flow,lower cost and good product consistency.Features.The main work carried out by the paper includes:(1)Analyzed the research status of MEMS high-temperature pressure sensors at home and abroad,expounded the working principles of various types of pressure sensors and analyzed their characteristics to determine the main content of the paper.(2)The working principle of the strain-type MEMS pressure sensor is studied,the pressure-sensitive membrane and strain resistance are analyzed,and a new structure of metal strain resistance differential MEMS pressure sensor is proposed,which realizes the concentration of stress through the island-membrane structure.(3)Simulated the sensor structure.The influence of the stress distribution of the silicon sensitive film and the silicon island length-to-width ratio on the stress distribution of the silicon sensitive film under different loads are analyzed,the stress concentration distribution area is determined,the structure optimization design is completed and the simulation APP program is designed.(4)Completed the sensor layout design and processing process design.Adopt the process flow of making strain resistance first and then wet etching,analyze the key processes such as etching,design the silicon wafer single-sided corrosion fixture,avoid the direct contact between the strain resistance of the pressure sensor and the etching liquid,and complete the sensor chip Manufacturing.(5)Sensor package thermal effect analysis and preliminary performance test.The thermal stress of the packaging adhesive and the heat dissipation of the sensor are simulated and analyzed,and the preliminary packaging and performance testing of the sensor chip are completed.The test results show that the strain resistance of the sensor is about 1640 ohms,the error is ± 1.2 ‰,the linearity is good,and it can work normally at200 degrees Celsius.