A Photolithography Laboratory Experiment for General Chemistry Students

Photolithography is the primary means of pattern transfer used in the production of a multitude of microfabricated devices, including integrated circuits, microelectromechanical systems, and optoelectronic devices. The underlying photochemical process inherent to lithography is an attractive model system to introduce photochemistry, reaction kinetics, polymer chemistry, and materials science to a broader audience in a general chemistry laboratory setting. We report a second-semester general chemistry experiment in which students design and produce a photomask to pattern a silicon wafer using optical lithography. In addition to substrate patterning, students examine the reaction kinetics of the photobleaching process of the photoresist system using a UV–vis spectrometer operating in the kinetics mode. Both experiments introduce lower-division students to a technologically important industrial chemistry process and aid in understanding the topics of polymer chemistry and photochemistry.