A method to repair ceramic substrates is disclosed using a novel polyimide polymer which has high thermal stability, resistance to fluxes and flux residue cleaning solvents and processes, good mechanical properties, good adhesion to all contacting surfaces with low moisture uptake and good flow properties suitable for repairing chipped ceramic, filling deep trench or vias and writing passivation lines with automated process The polyimide polymer is made by reacting aromatic dianhydride and aromatic diamine monomers with a stoichiometric offset and end capping the resulting polymer when the reaction is completed. The preferred polyimide is made using a molar excess of diamine which is end-capped using an anhydride.