Inhibition of Bump Formation in Copper Superfilling by Cl^– Rich Bath

Abstract

Electrochemical deposition is used for copper deposition in the damascene process , because preferential deposition from trench bottom is achieved by several additives in the plating bath. However, accelerators remain on the plating surface and bumps, which makes planarization process difficult, are formed on trench concentrated area. In this study, it was found that reverse current in Cl^– rich bath prompts the accelerator desorption and inhibition of bump formation by Cl^– rich bath is demonstrated.