Chemically amplified resists based on acrylate polymers containing ketal groups in the side chains

摘要

We have examined a novel class of ketal based deep UV photoresist. 1,4-Dioxaspiro(4,4)nonane-2-methyl methacrylate was synthesized and polymerized. A ketal group of poly(1,4- dioxaspiro(4,4)nonane-2-methyl methacrylate) hydrolyzes under acid catalysis to give two alcohol functionalities and a cyclopentanone molecule. The ketal polymer is insoluble in an aqueous developer, while the hydrolyzed products are soluble.It was found the cyclopentanone product affects diffusion of acid in the resist. As a result, the generated cyclopentanone increases mobility of the acid significantly.