This paper describes how the new Hoya Micro Mask APTCON 4045 optical mask processor was used in conjunction with the ETEC CORE 2564 reticle writer in the optimization of a 64 Mb DRAM process. Exposure conditions, develop/etch parameters, and processor variables were individually optimized; results from the ensuing process are analyzed. The major components of the Convac-APT APTCON 4045 processor are described. The system description, physical layout, automation, chemistry handling, and adjustment versatility are all covered. Cassette-to-cassette full automation is used, in support of an extremely tight control over process variability. Fully automatic chemistry handling is implemented, with supply auto- switch, in an isolated safety enclosure. The on-line chemistry and D.I. water are kept under accurately controlled conditions. Great adjustment versatility in the chemistry dispense is provided through unusually maneuverable devices. In addition, other process variables (such as the air velocity and spin speed) can be controlled with unique fineness and range.