Plasticity in Self-Assembly: Templating Generates Functionally Different Circuits from a Single Precursor

摘要

The fabrication of microelectronic circuits now follows a strict, deterministic, top-down plan, and relies on the massive parallelism of photolithography to produce multiple replicates of a device. Neural circuits follow and adaptive, bottom-up plan, and assemble themselves of individual components-cells-following a combination of internal program and external guidance. The work we report herein is an initial step towards a strategy for the fabrication of electrical circuits that also relies on a combination of self-assembly and external guidance. We demonstrate the self-assembly of mm-sized components into 3D aggregates that have structures and patterns of electrical connections determined by the shape of a template-that is, by the geometry of the volume in which the self-assembly proceeds. The components carry lightemitting diodes (LEDs). used as surrogates for more complex microelectronic devices, connected to solder-covered pads. The solder connecting these components-when liquid-acts through capillary interactions to drive the self-assembly of the components, and-when solid-establishes electrical and mechanical connections between selected LEDs. Self-assembly in containers of different shape generates topologically different 3D structures-helices, zigzags, and combinations of the two; these structures have different patterns of electrical connections among the LEDs.