Microfabricated, ultra-dense, three-dimensional metal coils

This paper focuses on the fabrication of three-dimensional coils with high packing density. The process consists of electroplating a first sequence of metal microstructures, followed by conformal insulation of these conductors by a vapor-deposited parylene layer, and subsequent electrodeposited metal filling between the first-layer conductors. The windings are microfabricated as an array of two-dimensional coils, which are later released from the substrate, folded and electrically connected to form a three-dimensional coil device. The MEMS-fabricated, ultra-dense coils exhibited a 62% improvement in packing density over conventional wire-wound coils.