Capillary And Magnetic Forces For Microscale Self-Assembled Systems

Abstract

Self-assembly is a promising technique to overcome fundamental limitations with integrating, packaging, and generally handling individual electronic-related components with characteristic lengths significantly smaller than 1 mm. Here we briefly summarize the use of capillary and magnetic forces to realize two example microscale systems. In the first example, we use capillary forces from a low melting point solder alloy to integrate 500 μm square, 100 μm thick silicon chips with thermally and chemically sensitive metal-polymer hinge actuators, for potential medical applications. The second example demonstrates a path towards self-assembling 3-D silicon circuits formed out of 280 μm sized building blocks, utilizing both capillary forces from a low melting point solder alloy and magnetic forces from integrated, permanent magnets. In the latter example, the utilization of magnetic forces combined with capillary forces improved the assembly yield to 7.8% over 0.1% achieved previously with capillary forces alone.

Self-Assembly of Microscale Parts through Magnetic and Capillary Interactions

“…We also describe experimental methods to fabricate the parts in Figure 1, using a single crystal silicon substrate and steps, which are entirely compatible as a post process to any CMOS or wafer-scale packaged microelectromechanical device. Finally, we present self-assembly results which build on those presented in a recent conference paper [37].…”