Building and Testing a Photolithographic System

Photolithography is a technique used to deposit metals onto substrates in specific patterns. The process uses light to transfer geometric patterns onto a light sensitive photoresist on the surface of a substrate. We have built a low-cost, maskless photolithographic system assembled from a computer, a consumer projector, and a microscope. The photoresist is spun in a modified food processor and baked on a standard hot plate. Exposing the photoresist only takes a few minutes and allows for multiple runs on the same substrate in a short amount of time. Through multiple exposures, we can make features ranging from approximately 8 $\mu $m to 785 $\mu $m, which is especially useful when making contacts using the large features.