Process for preventing corrosion of aluminum bonding pads after passivation/ARC layer etching

摘要

A method for etching access opening to aluminum alloy wire bonding pads of integrated circuit chips is described wherein a polymer layer is in-situ deposited into the opening after the bonding pad has been exposed by dry etching of a passivation layer. The passivation layer, is first etched with fluorocarbon etchants and then a TiN ARC layer is removed from over the aluminum bonding pad with etchants which may contain chlorine either as etch components or as a contaminant in an etchant such as SF6 non-volatile chlorine containing residues including AlCl3 and trapped Cl2, are left behind after the ARC layer has been removed. These cause corrosion of the bonding pad when exposed to atmospheric moisture. The polymer layer deposited immediately after the pad surface is exposed by the etchant, provides a temporary seal over the aluminum bonding pad, protecting it from exposure to moisture during subsequent processing steps.