Improvement of Sensitivity and Resolution by Carboxylic Acid Type Dissolution Inhibitor in Three-Component Chemically Amplified Photosensitive Polyimide

In this paper, we improved both the sensitivity and resolution of photosensitive polyimide (PSPI) by using the highly acidic dissolution inhibitor (DI) in three-component chemically amplified PSPI. The PSPI consists of a polyimide, DI, and a photoacid generator. The DIs were phenol type dissolution inhibitors (tBoc-DI) and carboxylic acid type dissolution inhibitors (tBu-DI). PSPIs containing tBu-DI were more sensitive than those containing tBoc-DI. In all PSPIs, 3 μm line-and-space (L/S) patterns were successfully produced at the initial film thickness of ca. 3.5 µm. The pattern shape of PSPIs containing tBu-DI were closer to a rectangle and higher resolution than that of PSPIs containing tBoc-DI. These results were attributed to the fact that tBu-DI exhibited higher dissolution acceleration in the exposed area than tBoc-DI. These results reveal that tBu-DI resolves the trade-off between the sensitivity and resolution of the PSPI.