stepper

thumb|250px|An Mercury-vapor lamp#Emission line spectrum|i-line stepper at [[Cornell NanoScale Science and Technology Facility. (Photo taken under inactinic light.)]]

A stepper or wafer stepper is a device used in the manufacture of integrated circuits (ICs). It is an essential part of the process of photolithography, which creates millions of microscopic circuit elements on the surface of silicon wafers out of which chips are made. It is similar in operation to a slide projector or a photographic enlarger. The ICs that are made form the heart of computer processors, memory chips, and many other electronic devices.