Phenomenology of ArF photoresist shrinkage trends

This paper focuses on ArF and iArF photoresist shrinkage. We evaluate the shrinkage magnitude on both R&D resists and mature resists as a function of chemical formulation, lithographic sensitivity, SEM beam condition, and feature size. The results lead to a much improved understanding of the mechanics of the shrinkage phenomenon, with many implications for SEM metrology as the industry moves to smaller target features. A key finding is that smaller features shrink less but at a much faster rate than larger features and that this behavior is very dependent on the interaction volume size of the electron beam relative to CD.