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 . An emulsion for electrophoretic deposition of a coating of a photoimageable, aqueous acid soluble polyimide polymer, said emulsion comprising: 
 a dispersed phase including said photoimageable, aqueous acid soluble polyimide polymer dissolved in an organic solvent; and    a dispersion phase including at least one coalescence promoter and water.    
     
     
         2 . An emulsion according to  claim 1  wherein said organic solvent is selected from the group consisting of N-methylpyrrolidone, y-butyrolactone and dimethylformamide.  
     
     
         3 . An emulsion according to  claim 1  wherein said coalescence promoter is selected from the group consisting of n-butyl-cellosolve, propylene glycol monomethyl ether, propylene glycol ethyl ether acetate, propylene glycol methyl ether, propylene glycol n-butyl ether, propylene glycol n-propyl ether, propylene glycol phenyl ether, dipropylene glycol, propylene glycol, propylene carbonate, propylene glycol ethyl ether, propylene glycol methyl ether acetate, ethylene glycol monomethyl ether, butylene glycol, diethylene glycol, diethylene glycol ethyl ether, ethoxyethanol, ethoxy ethanol acetate, ethylene glycol, triethylene glycol, ethylene glycol diacetate, ethylene glycol propyl ether, methoxy ethanol acetate, methoxy ethanol, phenoxy ethanol, n-butanol, di(ethylene glycol) butyl ether, and 2-ethyl hexanol.