Role of counter-anion chemistry, free volume, and reaction byproducts in chemically amplified resists

Fundamental understanding of the physical processes controlling deprotection in chemical amplified resists (CARs) is critical to improve their utility for high-resolution lithography. We employ a combined experimental and computational method to examine the impacts of excess free volume generation, reaction byproducts, catalyst clustering, and catalyst counter-anion chemistry/size on deprotection rates in a model terpolymer CAR. These studies suggest that catalyst diffusion can be enhanced by a combination of excess free volume and reaction byproducts, and that counter-anion chemistry/size plays a key role in local reaction rates, which stems from differences in the rotational mobility of the catalyst.