Nikon Corp, from its base in Belmont, California has announced development of an excimer stepper, an optical lithography system for pre-production of 64M-bit dynamic random access memory products: the NSR-1755EX8A has a resolution of less than or equal to 0.45 micron in an exposure area of 17.5mm by 17.5mm or 24.75mm diagonal; the size will accommodate two 16M images and is designed for 64M development; it uses a krypton fluoride excimer laser, which operates at 248 micron and permits the imaging of smaller particles in the sub-half micron regime; Nikon will take orders in the spring of 1991, and manufacturers such as Toshiba and Hitachi have indicated that 16M DRAM could be sampled next summer, with commercial qualification in 1992.
