Magnetic Field Sensors for Non-Invasive Current Monitoring in Wire-Bond-Less Power Modules

A non-invasive implementation of a planar magnetoresistive sensor on top of copper interconnected power modules is proposed. This solution allows for the real-time monitoring of the electrical current flowing across the power modules. Anisotropic magnetoresistive (AMR) sensors made of Permalloy were designed through finite-difference and finite-element simulations in the so-called barber-pole configuration and microfabricated via patterning by laser lithography and thin film deposition by electron-beam evaporation. Finally, the sensor performance was tested by measuring the magnetic field generated by the electrical current in a specific range of interest.