Design And Implementation Of AMR Integrated Angle Sensor Chip

With the rapid growth of China's economy and the enhancement of its scientific and technological strength,economic trade friction and technological confrontation between China and foreign countries have become increasingly frequent.In recent years,countries led by the US have imposed sanctions on China's aviation,information technology,biotechnology,integrated circuits and other sectors.It makes the integrated circuit(IC)and even semiconductor industry has been impacted,greatly affecting the process of China's scientific and technological development.At present,China is in the transition from 4G to 5G,which is an important science and technology in the era of the Internet of everything.As a key device,sensor can skillfully connect IC design with Internet of Things.Therefore,China needs to vigorously study sensor chip related technology.Among them,angle sensor is widely used in sensors,so the breakthrough and mastery of Angle sensor technology is very important.The Anisotropic magnetoresistance(AMR)Angle sensor occupies most of the Angle sensor market with its good stability and excellent performance.At present,most foreign enterprises mainly improve the performance of AMR Angle sensor from magnetic film material,sensor structure and manufacturing process.And most domestic enterprises mainly from the AMR Angle sensor algorithm,chip peripheral circuit,to improve the performance of AMR Angle sensor.These two solutions to improve the performance of AMR Angle sensors,which should be one and the same,are now split into two parts.In view of this phenomenon,this paper mainly studies the principle of AMR Angle sensor,the preparation method of the sensor,the design of the external circuit of the sensor and the algorithm of the sensor to improve the AMR effect of the sensor,and improve the performance of the AMR Angle sensor.The specific research contents are as follows:Firstly,this paper starts with the basic principle of AMR Angle sensor,and selects Ni Fe and Ni Co materials.At the same time,according to the relationship between the resistivity of thin film material and the thickness and total length of wheatstone bridge,the shape of wheatstone bridge and the total length of wheatstone bridge are designed.In order to grow the designed Wheatstone bridge pattern on the substrate,this paper uses CAD software to make a mask matching the bridge pattern.Subsequently,Ni Co and Ni Fe films were grown by magnetron sputtering method.By comparing the AMR effect,Ni Co films with a thickness of 50 nm and a width to length ratio of 1:11 were selected.The annealing temperature was 150 ? and the time was 0.5 h.In this paper,the substrate is encapsulated into nine independent sensors through wire-bonding and other packaging technologies,which have the advantage of 120 Oe saturation field.In addition,the Printed Circuit Board(PCB)is designed using EDA tools.In order to test the performance of AMR sensor,this paper uses 3D printing technology to build a support for the test platform.The Angle algorithm of AMR sensor is studied,such as DC bias correction algorithm,amplitude correction algorithm,phase correction algorithm and CORDIC algorithm.To further collect and process the test data,the test software is written.The data processing chip reads the data in the ADC through Serial Peripheral Interface(SPI)protocol.The PC reads data from the data processing chip through the Universal Asynchronous Receiver/Transmitter(UART).Finally,the current Angle is calculated according to the Angle solution formula.The final test error is 0.53°,similar to the market Angle sensor error.