Research On Manufacturing Process And Characteristics Of Angle Sensor Based On NEMS Technology

With the continuous improvement of people's requirements for the practicability,safety,mobility,environmental protection and economy of automobiles,more and more angle sensors are applied to the field of automobiles.In this paper,an angle sensor based on Giant Magnetoresistance(GMR)element is presented.The change of magnetic field is transformed into the change of angle value by the Giant Magnetoresistance element,which is used to measure plane angle.The angle sensor is composed of a sensor chip,a small magnet(applying a magnetic field),a stator(placing a sensor chip),a rotor(placing a small magnet)and a dial(calibrating the current angle),etc.The basic structure of the sensor chip is mainly composed of two Wheatstone Bridges placed at 45°.Each Wheatstone bridge consists of four multilayer GMRs,and the multilayer GMR is composed of three parts,from bottom to top are the substrate(Si O₂/Si),and the(Co/Cu/Co)_n multi-layer films and the top electrode(Al layer).The integrated circuit layout design software L-Edit was used to design the layout of the magnetic sensitive unit of the different sizes angle sensor.The(Co/Cu/Co)_n multi-layer films were prepared on the thermically oxidized high resistance monocrystalline silicon substrate by magnetron sputtering,By optimizing the width of the resistance strip of the magnetic sensitive unit of the angle sensor,the manufacturing position of the top and bottom electrodes and the process parameters,the magnetic sensitive unit with high sensitivity is selected.On this basis,the use of NEMS technology to complete the production of monolithic angle sensor chips,the use of Altium Designer software to design the printed circuit board(PCB)layout,the use of inner lead ultrasonic pressure welding technology to achieve the angle sensor chip packaging,using 3D printing technology produces the rotor,stator and dial to realize the packaging of the angle sensor.At room temperature,when the constant voltage V_DD=5.0 V,a high-precision magnetic field generator system and a rotation test system are used to test the magnetic characteristics and calibrate the rotation characteristics of the angle sensor chip.The experimental results show that the angle sensor can achieve the angle measurement range of 0?180°,and the resolution of the angle sensor can reach 1°.