Optimizing Plasma Surface Interactions for Materials Processing: Microelectronics to Polymer Processing

Plasma materials processing is indispensable to microelectronics fabrication, as well as to the manufacture of a surprising large number of products, from applications of commodity polymers to biocompatible materials. A unique attribute of using plasmas for materials processing is the ability to controllably produce fluxes of chemically reactive species to surfaces at low temperatures. Optimizing those fluxes, both neutrals and ions, often depends on complex interdependencies between the plasma source, reactor geometry and the surface to be processed. For example, merely increasing the frequency of excitation of a plasma etching reactor can have profound effects on the composition and uniformity of reactant fluxes. In this talk, results from computational investigations of optimizing plasma-surface interactions for materials modification will be discussed. The modeling platforms used in these investigations are multidimensional plasma hydrodynamics simulations which include surface kinetics, profile evolution and radiation transport. Examples will be used from two extremes of materials processing to provide a sense of the challenges and opportunities. At one extreme is low pressure plasma processing for microelectronics fabrication. In this application, controlling the delivery of activation energy to wafers with nearly eV resolution is required. Strategies including magnetic fields, non-sinusoidal waveforms and reactor design will be discussed, as well as the challenges of retaining this needed control as features sizes decrease and wafer sizes increase. At the other extreme is the atmospheric pressure plasma functionalization of polymers. The extension of processes now commonly used for functionalizing commodity low value materials to create high value biomaterials will be discussed.
Mark J. Kushner received the B.A. in Astronomy and B.S. in Nuclear Engineering from the University of California at Los Angeles in 1976. His M.S. and Ph.D. degrees in Applied Physics were from the California Institute of Technology in 1977 and 1979, respectively, where he was also the Weizmann Postdoctoral Research Fellow. Prof. Kushner served on the technical staffs of Sandia National Laboratory and Lawrence Livermore National Laboratory before joining Spectra Technology, where he was Director of Electron, Atomic and Molecular Physics. In 1986, Prof. Kushner moved to the University of Illinois at Urbana-Champaign where he was the Founder Professor of Engineering in the Department of Electrical and Computer Engineering. His administrative roles included Assistant Dean of Academic Programs and Associate Dean for Administrative Affairs in the College of Engineering, Interim Head of the Department of Electrical and Computer Engineering, and Interim Head of the Department of Chemical and Biomolecular Engineering. He joined Iowa State University as Dean of Engineering and the Melsa Professor of Engineering in January 2005. His primary academic appointment is in the Department of Electrical and Computer Engineering; and he is an Affiliate of the Departments of Chemical and Biological Engineering; and Material Science and Engineering. Prof. Kushner continues his active research program in his role as dean. He has published more than 230 journal articles, made more than 350 contributed presentations and delivered more than 200 invited conference talks and seminars on topics related to plasma materials processing, lasers, lighting sources and pulse power plasmas. He is a Fellow of the American Physical Society, IEEE, the Optical Society of America, the American Vacuum Society, International Union of Pure and Applied Chemistry, and the Institute of Physics. Prof. Kushner has received the Semiconductor Research Corporation Technical Excellence Award, the Tegal Thinker Award for Plasma Etch Technology, the AVS Plasma Science and Technology Award, and the IEEE Plasma Science and Applications Award. He was also a Japanese Society for Advancement of Science Fellow. He serves on the editorial boards or is associate editor of Transactions of Plasma Science, Journal of Physics D, Plasma Processing and Plasma Chemistry and Plasma Processing and Polymers; and is Editor-in-Chief of Plasma Sources Science and Technology.