Micro-to millimeter scale magnetic shielding

We present two key results in this work related to magnetic shielding. First, milliscale single layer magnetic shields were fabricated on 3D printed polymer molds and achieved shielding factors in excess of 4500. Second, microscale multilayer shields of alternating 10 μm layers of Permalloy and copper were microfabricated onto silicon using batch fabrication processes and characterized. While conventional electromagnetic interference (EMI) shielding simply requires a conductor for shielding by image charges, DC magnetic shielding requires high permeability material to provide a low reluctance path, redirecting magnetic fields around its volume. Leveraging our expertise in electroplating thick, high permeability (maximum μ
_r
> 8000) Permalloy over sharp topologies, we have demonstrated two processes of producing conformal electroplated shielding. The size, shape flexibility, and shielding factor of these structures enable compact integration of magnetic devices for magnetic microelectronics and atomic, molecular, and optical (AMO) microsystems.