Silicon-Polymer MEMS Processing: Transforming Applications in Actuation, Sensing, and Power
Professor Mark A. Shannon
Dept. of Mechanical and Industrial Engineering
Dept. of Electrical and Computer Engineering
University of Illinois at Urbana-Champaign
Integrating thin polymer films with surface and bulk micromachined silicon MEMS enables new types of microactuators, sensors, and power generators to be realized. Polymer films can add structural richness to the design of devices, as well as desirable properties of polymers, such as high-strength polymer diaphragm actuators, nanopore membranes for micro to nanofluidic interconnects, and proton exchange membranes (PEMS) in fuel cells. However, successfully integrating polymers films into silicon-based MEMS has been challenging, with critical questions that had to be answered in how to deposit, pattern, metalize, etch, bond, release, and stack multiple layers of similar and dissimilar polymers to silicon and glass substrates. A new processing construct has slowly emerged over five years of work that have, for the most part, answered these questions. Much of the talk will focus on these challenges, and the physics, chemistry, and engineering solutions that have been found to date. Three examples of silicon-polymer MEMS to illustrate the power of this processing construct will also be presented: (i) a polyimide diaphragm high-pressure microcompressor actuator for micro-heat pumps, (ii) a microfluidic circuit with nanopore polycarbonate membranes creating molecular gate valves for protein separations to sense attomoles of toxins, and (iii) a Nafion® PEM for formic acid powered silicon micro fuel cells.
Mark A. Shannon is the Director of the Micro-Mechanical Systems (MMS) Laboratory at the University of Illinois at Urbana-Champaign, a 1600 sq. ft class 100 cleanroom laboratory designed for research and education in the design and fabrication of micro- and nanoelectromechanical systems (MEMS & NEMS) and mesoscale mechanisms, such as the Integrated Mesoscopic Cooler Circuit (IMCC), microscale fuel cells, high-temperature microchemical reactors, and micro-nanofluidic sensors for biological fluids. The focus of his research is developing new fabrication technologies and processes for these and other applications. He is an Associate Professor of Mechanical, Electrical, and BioEngineering at UIUC, and is an affiliate of the Beckman Institute of Advanced Science and Engineering. He received his B.S. (1989) M.S. (1991) and Ph.D (1993) degrees in Mechanical Engineering from the University of California at Berkeley, and received the NSF Career Award in 1997 to advance microfabrication technologies.