A novel amide-imide copolymer as a matrix resin for ultraviolet photoresists: Preparation, properties, and application

Abstract

The matrix resin as the backbone material plays a crucial role in the performance of a photoresist. In this study, a novel amide-imide copolymer, poly[N-(phydroxyphenyl) methacrylamide-co-N-phenylmaleimide], was successfully prepared. This copolymer was very close to 1:1 (molar ratio) in composition and was predominately alternating in structure during the copolymerization with an equimolar monomer feed ratio. It had good solubility in organic solvents and good film-forming characteristic, and it was also soluble in a basic aqueous solution. Differential scanning calorimetry and thermogravimetric analyses showed that it had a glass-transition temperature at about 290°C and excellent thermostability. Photolithographic experiments indicated that the UV photoresist formulated with this copolymer as a matrix resin, diazonaphthoquinone sulfonate as a photosensitizer, a solvent, and other additives had a resolution of about 1 μm, a contrast of 2.83, and a sensitivity of 28 mJ/cm2. This photoresist had good plasma etching resistance and could endure 260°C for 30 min without thermal deformation of the lithographic images. © 2010 Wiley Periodicals, Inc.