Photoimageable, aqueous acid soluble polyimide polymers

Abstract

A photoimageable, aqueous acid soluble polyimide polymer comprising an anhydride, including a substituted benzophenone nucleus, a diamine reacted with the anhydride to form a photosensitive polymer intermediate, and at least 60 Mole % of solubilizing amine reacted with the photosensitive polymer intermediate to form the photoimageable, aqueous acid soluble polyimide polymer. An emulsion for electrophoretic deposition of a coating of a photoimageable, aqueous acid soluble polyimide polymer comprises a dispersed phase, including the photoimageable aqueous acid soluble polyimide polymer, dissolved in an organic solvent and a dispersion phase including a coalescence promoter and water. The emulsion may be applied, by electrophoretic deposition, to a conductive structure to provide a photoimageable coating on the conductive structure. After exposing the coating to a pattern of radiation for photocrosslinking exposed parts of the photoimageable aqueous acid soluble polyimide polymer, an aqueous acid developer solution removes unexposed photoimageable aqueous acid soluble polyimide polymer to reveal a crosslinked polyimide polymer image of the radiation pattern.

What is claimed is:  
     
         1 . A method for imaging a photoimageable aqueous acid soluble polyimide polymer applied to a conductive structure used for connecting electrical and electronic components, said method comprising the steps of: 
 providing a conductive structure used for connecting electrical and electronic components;    applying a coating to said conductive structure using an electrophoretic coating technique, said coating comprising an anhydride including a substituted benzophenone nucleus; a diamine reacted with said anhydride to form a photosensitive polymer intermediate; and at least 60 Mole % of a solubilizing amine reacted with said photosensitive polymer intermediate;    exposing said coating to a pattern of radiation for photocrosslinking of exposed parts of said photoimageable aqueous acid soluble polyimide polymer; and    applying an aqueous acid developer solution to remove unexposed photoimageable aqueous acid soluble polyimide polymer to reveal a crosslinked polyimide polymer image of the radiation pattern.    
     
     
         2 . A method according to  claim 1 , wherein said aqueous acid developer contains an acid selected from the group consisting of acetic acid, ethoxyacetic acid, propionic acid, butyric acid, lactic acid, glycolic acid, formic acid and succinic acid and mixtures thereof.