Research On The Characteristics Of Micro-pressure Sensor With Isosceles Trapezoidal Beam Membrane Structure Based On MEMS Technology

Aiming at the problem of micro pressure measurement,a micro pressure sensor with isosceles trapezoidal beam membrane structure was designed based on MEMS(Micro-Electro-Mechanical System)technology in this paper.The micro pressure sensor consisted of a square silicon membrane,four isosceles trapezoidal beams(B₁,B₂,B₃and B₄)and four piezoresistors(R₁,R₂,R₃ and R₄).The elastic element of micro pressure sensor constructed by the square silicon membrane and four isosceles trapezoidal beams.The sensitive element of micro pressure sensor composed of four piezoresistors.When the applied pressure was perpendicular to the sensor,the isosceles trapezoidal beam membrane structure produces stress concentration effect.Based on piezoresistive effect,the sensor can realize micro pressure measurement.The ANSYS15.0 software was used to build simulation models to study the influence of different structure and size of elastic element on the pressure sensitive characteristics for micro pressure sensor.At the same time,the size of micro pressure sensor with isosceles trapezoidal beam membrane structure was optimized.On this basis,the layout of micro pressure sensor was designed by L-Edit.MEMS technology was used to complete the fabrication of micro pressure sensor on n type monocrystal silicon with double sided polishing.The inner lead bonding technology was adopted to package chip.The static characteristic test system of the micro pressure sensor was used to test the characteristics of micro pressure sensor in this paper.The sensitivity and non-linearity of micro pressure sensor with isoseles trapezoidal beam membrane structure were 9.64 mV/kPa and 0.09%F.S.at room temperature in the pressure range of0?3 k Pa and a supply voltage of 5.0 V.The sensitivity temperature coefficient of micro pressure sensor with isosceles trapezoidal beam membrane was-1831 ppm/?from-40?to 85?.The results show that the micro pressure sensor with isosceles trapezoidal beam membrane structure was designed and fabricated in this paper can measure 0?3 kPa pressure and has good pressure sensitive characteristics,which has great significance to the further application of micro pressure sensor.