1X deep UV lithography with chemical amplification for 1-micron DRAM production

This paper describes methods used and results obtained in the production of 1-megabit (Mb) DRAM chips, using a chemically amplified tcrtiary-butoxy carbonyl hydroxystyrene (t-BOC) resist and IX lithography. The internally developed resist provided high sensitivity and contrast, Tor I μm resolution on a Perkin Elmer Micralign model 500 (PE 500) in the deep UV. Characterization, and modification of the PE 500 were required for this first application in the deep UV. The manufacturing process had photo limited yield in excess of 95% with a throughput of 100 wafers per hour.