The investigation of galvanic corrosion in post-copper-CMP cleaning

Abstract

The characteristics of galvanic corrosion in post-copper CMP cleaning are investigated. This type of corrosion occurs when CMP process completed, due to the heating lamp in SRD step. Particularly, it occurs only in device wafer, but not in structural test wafer. The corrosion behavior with light was identified. It occurs not only in integrated cleaner, but also in stand alone brush type cleaner. Copper lines were bridged after corrosion. The corrosion by-product can be removed by means of solvent cleaning. The mechanism and the prevention of this type of light-induced corrosion are reported in this paper.