Suppression of corrosion phenomenon on Al-1 %Cu surface with fluorine treatment

Abstract

The corrosion phenomenon of Al-1 %Cu surfaces has been investigated after etching with a Cl-based plasma gas. The as-deposited surface of Al-1 %Cu contains large grain-boundary areas, and the corrosion progresses mainly at the grain boundaries due to the imperfect crystalline state. It is confirmed that SFs plasma treatment at a pressure of the 300 mTorr after the etch process prevents the corrosion effectively. This is due not to the chlorine on the etched surface substituted for the fluorine atoms during SFs treatment, but to a passivation layer of fluorine-related compounds formed on the surface. The passivation layer prevents moisture penetration in to the SF6-treated surface and suppresses the corrosion successfully.