I-line photoresist composed of multifunctional acrylate, photo initiator, and photo acid generator, which can be patterned after g-line photo-crosslinking

Abstract

A positive-tone photoresist which can be patterned after photo-crosslinking was prepared. The photoresist is mainly composed of a multifunctional acrylate having a tertiary ester structure, a photo radical initiator, and a photo-acid generator (PAG). Photolysis of the initiator induces crosslink of the acrylate, and acid generated from the PAG catalyzes decomposition of the crosslinked acrylate. By loading the acrylate with both the initiator, that is sensitive to g-line, and the PAG, that is sensitive to i-line, the crosslink of the coating was promoted by g-line exposure. The subsequent i-line photolithography yielded the patterns of the resulting crosslinked film. Photolithography of both conventional negative- and positive-tone photoresists was performed on the crosslinked films. The patterned film stacks could be removed after additional i-line exposure followed by post-exposure bake and development.