Magnetic Self-Assembly of Millimeter-Scale Components With Angular Orientation

The focus of this paper is the demonstration and evaluation of a multifunctional self-assembly process driven by the intermagnetic forces between permanent (hard) magnets on 1 mm ?? 1 mm ?? 0.5 mm Si parts. Composite bonded-powder micromagnets are embedded in silicon components using back-end low-temperature wafer-level microfabrication techniques. Part-to-part assembly is demonstrated by batch assembly of free-floating parts in a liquid environment with the assembly yield of different magnetic patterns varying from 88% to 90% in 20 s. Part-to-substrate assembly is demonstrated by assembling an ordered array onto a fixed substrate in a dry environment with assembly yield up to 99% in just 20 s. In both cases, diverse magnetic shapes/patterns are used to control the alignment and angular orientation of the components. Experimental analysis of many different magnetic patterns shows that patterns with more planes of rotational symmetry result in faster assembly speeds.