A Fabrication Method for Amorphous Wire GMI Magnetic Sensor with Microelectronic Manufacturing Technology

The amorphous wire demonstrates good soft magnetic properties and the giant magnetoimpedance (GMI) effect. However, the amorphous wire with a diameter ranging from several micrometers to several tens of micrometers is soft and thin; thus, it is difficult to handle and fabricate to achieve a magnetic sensor. In addition, the electrical contact resistance of the amorphous wire with pads shows wide distribution due to the contact area being hard to control when welding. To solve these problems, this article proposed a microelectronic fabrication method for an amorphous wire-based magnetic sensor. Glass wafer was used as the supporting substrate of the amorphous wire, and nonphotosensitive polyimide resin was employed as the electroplating mask. Electroplating was performed to achieve the electrical interconnection between the amorphous wire and pads on the substrate. The structure fabricated above was composed of amorphous wire and a supporting glass substrate. Then, the enameled wire was uniformly wound around the fabricated structure as a signal pickup coil. The test results showed excellent linearity within the range of -0.6 to +0.6 Oe and a sensitivity of 6.38 V/Oe.