Interactions at interface between Cu99Ti1 thin films and polyimide

Material characteristics and chemistry of the interface formed between Cu99Ti∼1 films and polyimide were investigated. Plasma pretreatment of the polyimide surface and post-metallization annealing were used to modify the interface. Composition analysis data taken from the interface indicated no significant Cu diffusion into the polyimide layer and accretion of nitrogen at the interface. The formation of Cu and Ti compounds by carbonyl bond breaking, suggested by x-ray photoelectron spectroscopy, could explain suppression of Cu diffusion and drastic increase of adhesion strength.