Improving the Electrical Contact Performance for Amorphous Wire Magnetic Sensor by Employing MEMS Process.

Area of Science:

• Materials Science
• Electrical Engineering
• Sensor Technology

Background:

• Amorphous alloy wire giant magneto-impedance (GMI) sensors offer high sensitivity for magnetic field detection.
• Conventional fabrication methods for GMI sensors often involve high temperatures and result in inconsistent impedance characteristics.

Purpose of the Study:

• To develop a novel, low-temperature fabrication process for amorphous alloy wire GMI magnetic sensors using micro electro mechanical systems (MEMS) technology.
• To evaluate the performance and consistency of GMI sensors fabricated with the proposed MEMS method compared to conventional techniques.

Main Methods:

• Utilized negative SU-8 thick photoresist as a solder mask for its stability and mechanical properties.
• Employed low melting temperature solder paste for electrical connections between the amorphous alloy wire and electrode pads.
• Fabricated GMI sensors using a micro electro mechanical systems (MEMS) process at a low temperature of 150 °C.

Main Results:

• The MEMS-fabricated GMI sensors exhibited superior impedance consistency, with a resistance variance of 0.029 Ω², compared to conventional methods (7.559 Ω²).
• The MEMS process allowed for fabrication at a low temperature of 150 °C.
• Achieved sensor sensitivity of approximately 150 mV/Oe with nonlinearity below 0.92% F.S.

Conclusions:

• The proposed MEMS fabrication method offers a significant improvement in impedance consistency for amorphous alloy wire GMI magnetic sensors.
• This low-temperature MEMS process is a viable alternative to conventional fabrication methods, providing enhanced performance and reliability.