Integrated fluxgate device

Abstract

An integrated circuit has a substrate, a circuit, a core structure, a first encapsulation layer, a second encapsulation layer, and an oxide layer. The circuit includes transistors with active regions developed on the substrate and a metal layer formed above the active regions to provide interconnections for the transistors. The core structure is formed above the metal layer. The first encapsulation layer covers the core structure, and it has a first thermal expansion coefficient. The second encapsulation layer covers the first encapsulation layer over the core structure, and it has a second thermal expansion coefficient that is different from the first thermal expansion coefficient. As a part of the stress relief structure, the oxide layer is formed above the second encapsulation layer. The oxide layer includes an oxide thickness sufficient to mitigate a thermal stress between the first and second encapsulation layers.