High-Contrast Chemically Amplified Photodefinable Poly(benzoxazole) Using Dissolution Reversers

A novel thermal-stable positive-tone photodefinable material has been proposed which applies chemical amplification system to a poly(benzoxazole). To fabricate thick film and also to obtain high dissolution contrast, we paid attention to a three-component system consisting of a poly(benzoxazole) precursor, photoacid generator, and dissolution reverser. In this paper, we describe the design concept of dissolution reversers affording a significant difference in dissolution rate between the exposed and the unexposed area. Moreover, we discuss the photolithographic and film properties of the proposed material. On the basis of the dissolution behavior study, we have designed some promising dicarboxylic acid derivatives for dissolution reversers. We found that the chemically amplified poly(benzoxazole) using the dissolution reversers will afford excellent photolithographic properties such as high sensitivity, fine resolution, and good critical dimension control, along with excellent film properties comparable to those of the conventional non-photodefinable polyimide.