Nanometer precision positioning robots utilizing optimized scratch drive actuators

A novel surface micromachined robot powered by a gold wire tether is presented. The micro robot is capable of pushing a 2 mm x 2 mm x 0.5 mm chip over 8 mm across an insulated silicon wafer. The micro robot uses a unique assembly and packaging process and is created from large arrays of scratch drive actuators (SDA) connected to a gold wire tether bonded prior to release in an HF acid bath. The robot can be bonded to a ceramic substrate to create a movable platform that can be transferred to other driving surfaces where assembly line positioning tasks can be performed. A device model has been derived to define optimum SDA plate design for any fabrication process based only on material properties and geometry. The driving signal has also been optimized, consuming much less electrical power than previously published signals. Because the step size of the individual SDA is approximately 30 nm, the tethered SDA robots are expected to achieve similar placement precision for chip sized components. The SDA robot (Scratchuator) demonstrates the potential for low cost nanometer positioning of chip sized components for alignment and flip chip assembly as well as precision sample positioning for surface analysis. (C) 2001 Elsevier Science B.V. All rights reserved.