THE EFFECTS OF FLUORINE PASSIVATION USING SF6 PLASMA ON THE CORROSIONOF AL(CU 1-PERCENT) AT GRAIN-BOUNDARIES

Corrosion effects following the etching of Al(Cu 1 %) using a SiCl4/Cl -2/He/CHF3 gas plasma have been evaluated. The phenomenon has been stu died using X-ray photoelectron spectroscopy (XPS), scanning electron m icroscopy (SEM), and Auger electron spectroscopy (AES). It was found w ith SEM that the surface of Al(Cu 1 %) was mainly corroded at the grai n boundary. Using AES point analysis, the cause of selective corrosion at the grain boundary of Al(Cu 1 %) has been investigated. The fluori ne (F) and chlorine (Cl) on the etched Al(Cu 1 %) have been analyzed w ith AES. The results showed that the contents of F and Cl on the post- SF6 treated Al(Cu 1 %) were different at each of the analyzed position s such as the grain boundaries and crystalline regions. This seems to result from the imperfect crystalline structure of Al(Cu 1 %) grain bo undaries. The effects of subsequent in situ SF6 plasma treatment on th e etched Al(Cu 1 %) has been also examined using XPS. It was also conf irmed that F has passivated the Cl compounds. The AES and XPS results imply that Cl incorporated at the grain boundaries of the polycrystall ine Al(Cu 1 %) film accelerated the corrosion and could not be easily removed by subsequent SF6 plasma treatment.