Photosensitive engineering plastics based on reaction development patterning

Abstract

Photosensitive engineering plastics as typified by photosensitive polyimides are mainly used in the electronics industry to form fine patterns for uses in which they will not be removed for a long time. However, to impart photosensitivity, it is necessary to introduce a functional group into a polymer or to use a precursor polymer, which hinders further applications of these polymers. We have developed reaction development patterning (RDP) as a method of forming a fine pattern by promoting the reaction between carboxylic acid derivatives in a polymer chain and nucleophiles in a developer selectively at the exposed or unexposed area. Since engineering plastics such as polyimide and polycarbonate inherently have carboxylic acid derivative groups in their main chain, RDP can easily impart photosensitivity to a wide range of polymers, including commercially available engineering plastics. By using RDP, it is possible to form both positive- and negative-tone patterns from the same polymer. In this review, I will describe recent developments in the study of photosensitive engineering plastics by focusing on RDP. This review focuses on recent developments in the study of photosensitive engineering plastics based on reaction development patterning (RDP). RDP is a method of forming a fine pattern by promoting the reaction between carboxylic acid derivatives in a polymer chain and nucleophiles in a developer selectively at the exposed or unexposed area. Since engineering plastics such as polyimide and polycarbonate inherently have carboxylic acid derivative groups, RDP can impart photosensitivity to various polymers, including commercially available engineering plastics. Both positive- and negative-tone patterns can be formed by using RDP.