Earlier the effects of ion bombardment etching ceramic substrates (Al2O3) were studied on the adhesion strength and thermal contact resistance of sputtered copper films with the use of the scratch adhesion test and the thermal measurements, respectively. Most relations between thermal contact resistance and mean critical load use scratch tests to characterize adhesion. In order to understand the origin of the mean critical load and the thermal contact resistance evolution, observations were made by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results obtained have shown that the structural change of the copper film and the formation of a complex interface seem to be one of the main reasons for this evolution in argon treated samples.