Electrical components such as computer microprocessors and memory chips contain nanometer-level electrical circuits that have been patterned using a semiconductor exposure tool. A laser beam is shone on a "photomask," or an original circuit pattern, to create an image of the circuit on a silicon wafer. Creating such nanometer-level circuitry requires ultrahigh-precision lenses and wafer stages, which are used to carry the silicon wafers that serve as the foundations for semiconductor devices. Semiconductor exposure tools have played a key role in the remarkable advances made in semiconductor circuit integration in recent years.