The formation of inhibitive benzotriazole films on copper and copper alloyed with silver has been studied with scanning electrochemical microscopy (SECM) and X-ray photoelectron spectroscopy (XPS). The SECM measurements showed that the film grows rapidly on oxygen-free dehydrated copper (OF-HC) and that the rate depends on the substrate potential. The benzotriazole films were also observed on silver alloyed copper; however, electropolishing prevents film growth by enriching the surface with silver. XPS results show that the film consisted of [Cu(I)-BTA] on both materials. No evidence of [Ag(I)-BTA] was found. (c) 2006 The Electrochemical Society.