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Joseph Tibbs
University of Northern Iowa
NIST Research Intern
National Institute of Standards and Technology (NIST)
Final presentation
Semiconductor device features are becoming ever more microscopic, and methods must be developed for detecting and characterizing defects in the chips before they are sent to consumers. Some promising methods for Back End Of Line (BEOL) testing involve scanning probe microscopes, which use micromachined tips for very high resolution topological measurement. However, by sensing electrostatic force at the microscale, these same probes can be used to detect things under the surface of the sample. In this project, we focused on how electric fields from buried metal lines can impact the motion of a voltage-biased tip. These techniques, referred to here as Remote Bias Electrostatic Force Microscopy (RB-EFM) still need to be characterized for their precision and accuracy, for example by determining the way in which tip geometry can impact results. By measuring tip response on standard samples, we compared the results with computational models and used them to develop theory which supports the experimental results.
I grew up on a farm in rural Iowa, but I knew from a young age that I wanted to become a scientist. Now I'm a Junior Physics and Biochemistry major at the University of Northern Iowa. I joke that my double major means that I love science but could never decide on a discipline; while that's not far from the truth, it really means I love understanding the physics of biochemical systems. Bouncing between the Physics and Chemistry buildings on campus means that I tend to look at problems with a broad, interdisciplinary perspective, and I've had experience everywhere from pure computational research to human cell culture. I've mainly done work with simulations of biological systems and data analysis for biophysics experiments. Two summers ago, I worked on microscope image processing, which turned into a project in software development, which eventually became a partnership expanding the theory behind existing protein-binding experiments. During last summer's internship, I edited the code of a cytoskeleton simulation to run more efficiently, then took a sharp turn upon returning to my home university by testing drugs on human pancreatic cancer. But everywhere I go, I find that the principles of Physics and Biochemistry support and complement each other in new and surprising ways. All of this varied research might seem to point in no particular direction, but I do have a plan--or at least a thing like a plan, but with some room for flexibility. When I graduate next spring, I'll go on to a PhD program in either Biomedical Engineering or Biophysics. My path likely includes academic research, and becoming a professor has lately been one of my contingency dreams.
When I'm not doing science, I'm working at the tutoring center on campus, playing the carillon or the piano, or practicing my ballroom dancing. I love to read, both the centuries-old classics and the webcomic published yesterday.