Adhesion and interface chemical reactions of Cu/polyimide and Cu/TiN by XPS

The chemical reaction at the interface between Cu and polyimide (PI) and between Cu and TiN at room temperature has been investigated using X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). In case of Cu/TiN, there was no interface chemical reaction, but in case of Cu/PI system, there existed marked interface chemical reaction. From XPS core-level spectra, it was found that Cu atoms react mainly to oxygen and nitrogen in the PMDA (pyromellic-dianhybride) part of polyimide. Especially, the initial growth mode of Cu on polyimide was found by Cu LMM Auger spectra as follows; at first Cu-N-O complex is formed, then Cu-O-C complex formation by the weak interaction, and metallic Cu growth occurs simultaneously