Journal of Vacuum Science & Technology B, Vol.11, No.6, 2675-2679, 1993
Optical Projection System for Gigabit Dynamic Random-Access Memories
Containing the cost of new generations of optical lithography, while maintaining improvements in performance, is a major challenge because every three years tends to see a requirement for a three-fold increase in the number of resolvable pixels and a substantial improvement in resolution. Here an optical approach is reported that promises to ameliorate 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 corresponding 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.