Metal polyimide interface: A titanium reaction mechanism

Chemical bonding and reaction of in situ deposited Ti on a series of polyimide surfaces have been investigated. X-ray photoelectron spectroscopy has been used to probe site specific information for bonding of various functional groups of polyimide molecules, while ultraviolet photoelectron spectroscopy has been applied to monitor the change of the Ti d bands and the polyimide molecular orbitals near the Fermi energy as a function of overlayer coverage. At low coverages, the polyimide surfaces react strongly with Ti and strong charge transfer via the carbonyl group occurs. As the coverage increases, a Ti–C bond formation has been identified. A detailed mechanism for the reaction of Ti with polyimides is described, and this mechanism is confirmed by model pyromellitimide reaction with Ti0 suspension in solution.