Compositions for production of electronic coatings

Abstract

In humid atmospheres (e.g., 40% relative humidity or above) solutions of 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride/2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane polyimides tend to be unstable in the sense that during spin coating operations undesirable precipitate formation occurs on the rotating surface of the water. The result is the formation of unacceptable coatings due to their irregularity and lack of uniformity. Described are compositions especially adapted for use in spin coating wafers of semiconductive materials, which comprise solutions of these polyimide polymers in a solvent containing at least 10% of a cycloaliphatic ketone (e.g., cyclohexanone) or mixture of cycloaliphatic ketones, such that the solution (a) contains on a weight basis from about 5% to about 50% of the polyimide, and (b) does not undergo precipitate formation during spin coating in an atmosphere of up to at least about 55% relative humidity.