Fabrication Method of Flexible Fluxgate Sensor with Polyimide Substrate

Abstract

The application of fluxgate sensors in the fields of non-planar surface magnetic field measurement, online current measurement and wearable magnetic sensor will be greatly expanded if it is fabricated on the flexible substrates and can be bent. As a good substrate, insulation layer and protective layer, polyimide is compatible with standard MEMS processes. In this paper, a method for manufacturing a flexible fluxgate sensor with polyimide was investigated. A silicon dioxide layer with a thickness of 300 nm was grown on the silicon surface as a sacrificial layer, which was sufficient to release the sensor by immersion in an HF solution. Then a fluxgate sensor using polyimide as insulating layer, protective layer and substrate was prepared by a standard MEMS process. The fabricated sensor was tested, and the results show that: the sensor sensitivity reached about 2323V/T and the linear range reached about ± 200μT, which has achieved the performance of traditional fluxgates. The research results of this paper are expected to provide more theoretical support and engineering application suggestions on MEMS-based flexible substrate fluxgates.