Modeling and controlling the effects of base contamination in DUV lithography resists

摘要

The airborne base contamination of fast, chemically amplified photoresists is a yield-limiting factor in atmospheric pressure, deep-UV lithography and will remain so as device features continue to shrink. Lithography-induced critical dimension (CD) variations will have a particularly acute effect on device characteristics in the 150-nm technology node and beyond. The standard deviation of propagation delay times for CMOS-based ring oscillators, for example, will increase from 1% for 300-nm devices to 20% for 250-nm devices as a result of variations in gate oxide, impurity, and gate length.