Post-Cu CMP cleaning for colloidal silica abrasive removal

Abstract

In this study, an efficient approach for the removal of colloidal silica abrasives from the polished copper surface was proposed and demonstrated. This post-chemical mechanical polishing (CMP) cleaning process combines a buffing process with dilute HNO3/benzotriazole (BTA) aqueous solution for copper surface passivation and a polyvinyl alcohol (PVA) brush scrubbing process with wetting surfactants, Triton X-100, for colloidal silica removal. Buffing with HNO3/BTA aqueous solution was able to remove copper oxide and form the Cu(I)-BTA hydrophobic passivation. Scrubbing with Triton X-100 surfactant is to enhance the wettability on Cu(I)-BTA surface for the removal of residual silica abrasives. The wetting ability of Triton X-100 was determined by a contact angle and surface tension measurements. It was demonstrated that silica abrasives could be removed efficiently without copper corrosion by this cleaning process. (C) 2004 Elsevier B.V. All rights reserved.