Multiaxis microcoil sensors in standard CMOS

Abstract

The subsystems of an integrated MEMS 3D magnetic sensor are described and created using a standard CMOS fabrication process. For the completed sensor, after fabrication, the chip is micromachined and the sensor is assembled. The sensing is done by a two layer, aluminum coil whose equivalent area is specific to being sent off chip. The sensitivity and resolution of the transducer is found and shown to be a function of frequency. The frequency response is shown to be linear. Both higher sensitivity and finer resolution can be achieved by increasing the equivalent area of the micro-coil or by using a higher input frequency. The next phase is to fabricate the complete three axis system with two perpendicular coils rotated off the substrate and one remaining on the substrate.