Adhesion enhancement of magnetron-sputtered copper films by ion bombardment etching treatment of nickel and Inconel substrates: investigations by Auger electron spectroscopy and secondary ion mass spectroscopy of the ion beam effects

Abstract

Earlier the effects of ion bombardment etching of substrate surfaces on the adhesion strength of sputtered copper films deposited onto nickel and Inconel samples were studied using the scratch adhesion test. It was found that the mean critical load was very low unless the layer produced by mechanical polishing on the substrate surface was eliminated. After elimination of this layer, the mean critical load increased with increasing ion bombardment etching time, and for a sufficiently long ion bombardment etching, it became so high that it was impossible to observe evidence of an adhesion failure. In order to understand the origin of the mean critical load enhancement, observations were made by scanning electron microscopy (SEM) and Auger electron spectroscopy (AES). The results obtained showed that the mechanism of the adhesion strength enhancement was likely to be complex. However, it was suggested that the major part of the effect came from the elimination, by ion etching, of the layer produced by mechan...