Optical lithography: 40 years and holding

Optical lithography has been the dominant patterning process for semiconductor fabrication for over 40 years. The patterning process evolved initially from methods used in the printing industry, but as integrated circuits became more complex, and as device geometries shrank, sophisticated new imaging methods evolved. Today’s optical lithography systems represent the highest resolution, most accurate optical imaging systems ever produced. This remarkable evolutionary process continues to this day, paced by "Moore's Law". The evolutionary development of lithography systems over the last 40 years is reviewed along with a brief discussion of options for the future.