Differential solenoidal magnetic field sensing device and method for manufacturing the same

摘要

A differential solenoidal magnetic field sensing device is a magnetic field sensor fabricated on a microscopic scale and is constructed by two soft magnetic film cores laminated on a semiconductor substrate, an excitation of the soft magnetic film cores, and a magnetic flux variation detecting coil formed of a spirally wound metal film pattern. Since two soft magnetic film cores constitutes closed magnetic paths, leakage of magnetic flux can be minimized. Also, the magnetic sensing device is a differential type sensor, the combination of driving signals can be offset. That is to say, the magnetic field sensing device is constructed such that two soft magnetic film cores are laminated and are formed lengthwise in the direction of a detection axis to reduce anti-magnetic field components, and the excitation coil wound around the two soft magnetic film cores and the magnetic flux variation detecting coil for obtaining the sum of magnetic flux variations generated in the soft magnetic film cores are alternately wound turn by turn around the soft magnetic film cores.