The development of device lithography

Lithography has been the principal pacing element in the development of complex integrated circuits. Although major programs in electron-beam lithography and X-ray lithography have developed new systems with smaller feature capability, the optical systems remain the only candidates for large-volume device production. Scanning and step-and-repeat optical systems have been developed for the next generation of devices with 1-µm features. Electron beams are used for mask fabrication and direct exposure of special devices of exceptional value or for prototypes. X-ray and ion systems are being developed for future devices.