The Effects of Fluorine Passivation Using SF 6 Plasma on the Corrosion of Al(Cu 1%) at Grain Boundaries

Abstract

Corrosion effects following the etching of Al(Cu 1%) using a gas plasma have been evaluated. The phenomenon has been studied using X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Auger electron spectroscopy (AES). It was found with SEM that the surface of Al(Cu 1%) was mainly corroded at the grain boundary. Using AES point analysis, the cause of selective corrosion at the grain boundary of Al(Cu 1%) has been investigated. The fluorine (F) and chlorine (Cl) on the etched Al(Cu 1%) have been analyzed with AES. The results showed that the contents of F and Cl on the post‐ treated Al(Cu 1%) were different at each of the analyzed positions such as the grain boundaries and crystalline regions. This seems to result from the imperfect crystalline structure of Al(Cu 1%) grain boundaries. The effects of subsequent in situ plasma treatment on the etched Al(Cu 1%) has been also examined using XPS. It was also confirmed that F has passivated the Cl compounds. The AES and XPS results imply that Cl incorporated at the grain boundaries of the polycrystalline Al(Cu 1%) film accelerated the corrosion and could not be easily removed by subsequent plasma treatment.