The Research On Micro-Fluxgate Sensor Based On MEMS Process

Micro-fluxgate sensors based on MEMS technology have many advantages, including low power, high sensitivity, high resolution, simple structure and low cost. Therefore,the sensor has widely used in the magnetic studies, geological exploration, spatial magnetic field measurements, a small satellite positioning.According to the development of fluxgate sensors at home and abroad, firstly, the principle of the sensor is described in the thesis. The solenoid fluxgate sensor is designed based on the existing experimental conditions. This structure can effectively reduce the leakage of magnetic sensor and improve its inductance and quality factor. The finite element model of the solenoid flux gate sensor is constructed with ANSYS software. Various parameters are in detail analyzed, and magnetic field distribution inside and outside fluxgate are afforded. In addition, the numerical simulation of the sensor is carried out, specifically from the core, coil, insulation material and the substrate, analyzing their mutual influence. The optimization design is accomplished.During the production process, the long strip Ni / Fe alloy is used for the magnetic core, the coil highlights on the substrate. The magnetic core is the key structure, and the core directly affects the sensor sensitivity, resolution and size. The experiments show that sputtering and electroplating process can effectively improve the quality of the core. The plating process for Ni / Fe core is in-depth researched, and the plating parameters are optimized by the repeated experiments to determine the best solution. The manufacture processes for the fluxgate sensor are in detail investigated, including sputtering, lithography; electroplating, dry etching and wet etching MEMS technology, double-sided overlay, depth lithography, precision mechanical polishing and other key technologies. The prepared micro-fluxgate sensor size is 2.5mm×1.7 mm, the measure results show the magnetic sensitivity is 117 V / T.