SYNTHESIS AND EVALUATION OF POSITIVE-ACTING PHOTOSENSITIVE POLYIMIDES WITH PHENOL MOIETY

摘要

Novel positive-acting photosensitive polyimide resists (1) developable with an alkaline aqueous solution were prepared. The resists consisted of a naphthoquinone diazide (NQ) and a polyamic acid bearing hydroxyphenyl groups (PA). The hydroxyphenyl moieties are newly incorporated by adding 2-N,N-dimethylaminoethyl-3-hydroxybenzoate (m-PEA) or 2-N,N-dimethylaminoethyl-4-hydroxybenzoate (p-PEA) to the polyamic acid, through ionic interaction between the carboxylic acid and the amine. The NQ acts as a solution inhibitor for the PA by the interaction with the hydroxyphenyl moiety. This system is similar to that of phenol-novolac resin/NQ resists currently conducted in the fabrication of the Large Scale Integrated circuit (LSI). The resist (1) is exposed to a G-line and is developed with tetramethylammonium hydroxide aqueous solution to provide fine patterns, proving that the (1) is compatible with LSI-production lines currently applied. A novel polyamic acid-curing mechanism found in the course of this study is also reported. (C) 1995 John Wiley & Sons, Inc. [References: 21]