June 24, 2011 — Heidelberg Instruments (Germany) optioned University of Colorado (CU) Boulder’s technique for shrinking copper circuits by zapping a substrate with two separate colors of light beams. The shrinking technology could miniaturize circuits in semiconductors, nanomechanical devices, and photovoltaics.
The technique involves etching lines and dots in nm widths with a tightly focused beam of blue light, creating a lithography pattern on a substrate, commonly silicon. An ultraviolet light is then used to "erase" the edges of the pattern, shrinking the structure sizes.
The CU technology was developed by Associate Professor Robert McLeod of the electrical, computer and energy engineering department, Visiting Assistant Professor Tim Scott of the chemical and biological engineering department and Professor Christopher Bowman of the chemical and biological engineering department, with graduate students Benjamin Kowalski and Amy Sullivan (Sullivan is now a faculty member at Agnes Scott College in Decatur, GA). The technique was licensed to Heidelberg Instruments by the University of Colorado Technology Transfer Office.
McLeod and his colleagues used a tabletop laser to project tightly focused beams of visible blue light onto liquid monomer molecules. A chemical reaction initiated a bonding of the monomers into a plastic-like polymer solid. Focusing the blue beam in one place inscribed a small, solid dot. If the beam moved the focus across the material, it created a thin thread. An ultraviolet laser, focused into a halo, surrounded the blue light. The special monomer formulation was designed to be inhibited by the UV light, shutting down its transformation from a liquid to a solid. This prevented the edges of the spot or line from developing, resulting in a much finer final structure. The researchers refer to the light beam structure as the "halo of inhibition." Research on the project was funded by the National Science Foundation and through the University of Colorado Innovative Seed Program.
The CU Technology Transfer Office pursues, protects, packages and licenses the intellectual property generated from research at CU to businesses. For more information, visit www.cu.edu/techtransfer.
Heidelberg Instruments makes high-precision lithography systems. Learn more at http://www.himt.de/en/home/