The adhesion of thin evaporated Cu films directly to SiO2 is generally poor. The adhesion can be improved by a variety of treatments, ranging from a pre-deposition Ar ion bombardment of the substrate, to post deposition bombardments with ion beams, photons or electrons. Also, if a thin layer of partially oxidized Cr is deposited onto the SiO2 prior to Cu deposition, the Cu adheres more strongly. The intrinsic mechanism responsible for these adhesion improvements remains to be understood.
We have attempted to characterize the interface of these structures by a combination of Rutherford Backscattering Spectrometry (RBS) and an adhesion peel test to determine the role each treatment plays in the adhesion process.