Copper photocorrosion phenomenon during post CMP cleaning

During post-chemical mechanical polishing (CMP) cleaning of copper Damascen e structures by diluted hydrofluoric acid (HF), a corrosion phenomenon has been shown on patterned wafers, leaving a copper deposit and an associated copper etching. Methods are developed to eliminate the phenomenon hy use of benzotriazole or crotonic acid in the diluted HF solutions. At the same ti me, the presence of these inhibitors does not change the cleaning efficienc y of the diluted HF solutions. Also, the elimination of light during the cl eaning step eliminates the corrosion. A theoretical explanation is given. ( C) 2000 The Electrochemical Society. S1099-0062(99)10-108-1. All rights res erved.