Millimeter Scale Catoms

Realizing high-resolution applications that Claytronics offers requires catoms that are in the order of millimeters. In this work, we develop and demonstrate millimeter-scale catoms that are electrostatically actuated and self contained. As a simplified approach we build cylindrical catoms instead of spheres.

The millimeter scale catom consists of a cylindrical shell and a High voltage CMOS die attached inside the tube. The tubes are fabricated as double-layer planar structures in 2D using standard photolithography. The difference in thermal stress created in the layers during the fabrication processes causes the 2D structures to bend into a 3D tubes upon release from the substrate. The tubes have electrodes for power transfer and actuation on the perimeter.

The high voltage CMOS die is fabricated separately and is manually flip-chip bonded to the tube before release. The chip includes a rectifier, a charge pump for creating high voltages, a storage capacitor, a simple logic unit, and high voltage drivers.

The catom moves on a power grid (the stator) that contains rails which carry high voltage AC signals. Through capacitive coupling, an AC signal is generated on the coupling electrodes of the tube, which is then converted to DC power by the chip. The powered chip then generates voltage on the actuation electrodes sequentially, creating electric fields that push the tube forward.

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