Architectural Effects on Acid Reaction-Diffusion Kinetics in Molecular Glass Photoresists

Abstract

Understanding acid reaction-diffusion kinetics is crucial for controlling the lithographic performance of chemically amplified photoresists. In this work, we study how the molecular architectures of positive-tone chemically amplified molecular glass resists affect the acid reaction-diffusion kinetics during the post-expose bake (PEB) or annealing step. We compare the acid reaction-diffusion kinetics of a common photoacid generator in molecular glass resists with chemical similarity to poly(4-hydroxystyrene), and that are designed with branched and ring architectures. In situ Fourier transform infrared (FTIR) spectroscopy methods are used to measure reaction rate, acid trapping behavior, and acid diffusivity as a function of PEB temperature. We find that the acid reaction-diffusion kinetics in molecular glass resists is correlated to the film molar density that in turn depends on the architecture of the molecular glass molecules. These results allow modeling of the latent image formation in molecular glass...