OPTICAL PROJECTION SYSTEM FOR GIGABIT DYNAMIC RANDOM-ACCESS MEMORIES

Containing the cost of new generations of optical lithography, while m aintaining improvements in performance, is a major challenge because e very three years tends to see a requirement for a three-fold increase in the number of resolvable pixels and a substantial improvement in re solution. Here an optical approach is reported that promises to amelio rate the rapidly increasing cost of optical systems through the means of 1X, mostly reflecting optics. Only three projective components are required and the spectral range is 1000X larger than that of correspon ding refractive systems. Such a system appears capable of meeting the lithography requirements of the 256 Mbit dynamic random access memory (DRAM) and, with evolutionary improvements, the 1 Gbit DRAM.