Self-Assembly of Millimeter-Scale Components Using Integrated Micromagnets

This paper demonstrates and characterizes magnetically-directed self-assembly of 1 mm x 1 mm x 500 mu m silicon components into an ordered array on a planar substrate. Each silicon component includes an embedded, microfabricated magnet on, one surface that bonds to a corresponding magnetic receptor site (another embedded magnet) on the substrate. Two different magnet sizes are explored, corresponding to 25% and 75% of the bonding surface area. Using a shaker apparatus for mixing in a dry environment, studies are conducted to determine the assembly rates and yields. For the smaller magnets, a 4 x 4 array of components is shown to assemble onto a substrate with 97.5% yield in 10 s. The larger magnets indicate a 98.7% yield in 7 s.