Device photolithography: Lenses for the photolithographic system

The edge definition, maximum complexity and accuracy of details in photolithographic masks are limited by the performance of the lenses in the system. The tolerances on exposure, sensitivity and uniformity of the photosensitive materials, and processing are dependent upon the images formed exceeding the minimum quality required. The lenses in this system have been designed and fabricated to achieve the best practical performance at this time in order to obtain the largest tolerances possible. This paper details the design parameters chosen, the constructions used and the performance obtained by each of the lenses in the system.