Design of Dual-Sensitive Functional Photoresist for UV Lithography

In this study, we designed highly sensitive photoresist resins, JN05 and BN05, having both a photosensitive DNQ unit as a nonchemical amplification mode and the photo acid-cleavable groups like the ethyl vinyl ether (EVE) and diethyl decarbonate (BOC) protection groups as a chemical amplification mode. Resists with these dual-sensitive chemical reaction modes will undergo photolysis in the DNQ unit after exposure and further the acid-catalyzed deprotection reactions of the EVE and BOC groups after post-exposure bake. This dual-sensitized photolysis of the photoresist occurs at mild reaction conditions, enabling synergistic modifications by multiple functional groups. Upon exposure to doses of 150 mJ/cm2 and 90 mJ/cm2, respectively, JN05 and BN05 produced clear positive tone patterns with a line width of 1.0 μm (L/S = 1:1). Compared with the Novolac/DNQ system itself, the JN05 and BN05 photoresists combined the benefits of CA photoresists, nonchemically amplified solubility properties, and the multifunctional characteristics achieved by the DNQ system and CA comodification. The present work provides an approach for the improvement of photoresist sensitivity and resolution in the UV resist system.