A. V. Williams Building, Rm. 2460
For More Information:
301 405 3596
"Plasma Technology – Working Behind the Scenes to Make the World a Better Place"
Prof. Amy Wendt
Professor and Co-Chair, Electrical and Computer Engineering
University of Wisconsin, Madison
Friday, May 9, 2008
A.V. Williams Building, Rm. 2460
Plasmas -- they constitute more than 99% of the universe, but they also quietly toil in our homes and in industrial laboratories and production facilities to improve the quality of our everyday lives in a surprising number of ways. While plasma applications don’t often make headline news, science and technology of this richly complex medium are rapidly advancing with no end in sight, enabling development of the plasma TV, energy-saving compact fluorescent light bulbs, high-speed computer chips and photovoltaic solar panels, to name just a few examples. In this presentation, I will present a sampler of plasma applications, showcasing the unique qualities that make plasmas such an important technological tool. Activities in my research group will also be described, and will highlight the interplay between plasma science and technology. Specifically, we focus on how the plasma interacts with substrates in applications where plasmas are used to modify surface properties. We are particularly interested in energetic ions from the plasmas bombarding the substrate, a critical element of many plasma etch and deposition processes. Typically, the energy of bombarding ions is coarsely controlled through application of an rf voltage to the substrate, but in most cases the resulting spectrum of ion energies is quite broad. Finer control of the bombarding ion energy distribution (IED) to select specific energies can lead to improved process outcomes. Accurate and reproducible control of IED is also desirable as a means to better understand the nature of plasma-surface interactions. Described in this presentation is a method for IED control achieved by tailoring the waveform shape of an rf bias voltage applied to the substrate during processing, through the use of a programmable waveform generator in combination with a power amplifier. An automatic iterative approach using feedback control in the frequency domain is used to produce arbitrary waveform shapes at the substrate. Waveforms to produce ions at the substrate with energies greater than 500 eV in single-peaked or two-peaked IEDs are now routinely produced, and are applied to etching of silicon dioxide in fluorocarbon-based gas mixtures. Our results show that when even a small percentage of high energy ions reaches the substrate, process outcomes change dramatically, and we’re beginning to understand why. The presentation will include our working hypothesis and implications for plasma processing of materials.
Amy Wendt is Co-Chair and Professor in the Electrical and Computer Engineering (ECE) Dept. at UW Madison. Following completion of her Ph.D. at UC Berkeley in 1988, she came to UW as a postdoc in the then newly formed Engineering Research Center for Plasma-Aided Manufacturing. She joined the ECE faculty as an Assistant Professor in 1990, and was promoted to Associate Professor and Professor in 1996 and 2001, respectively. Her research is in the area of plasmas for materials processing. She was selected as a UW Vilas Associate for 2005-2007, the elected Chair of the Plasma Sciences and Technology Division of the American Vacuum Society in 2000-2001, and is now a member of the National Research Council Plasma Science Committee. She was a member of the Leadership Team of the Women in Science and Engineering Leadership Institute (WISELI) from 2001 to 2007, and has been Co-Director since 2007. She has served as Co-Chair of the ECE Dept. since 2007, and is also a member of the “CoE 2010” task force leading the UW College of Engineering as it redesigns itself to meet the challenges of engineering education in the 21st century.
This Event is For: Clark School