CMP in-situ conditioning with pad and retaining ring clean

Abstract

A method for preconditioning a CMP polishing pad and retaining ring prior to semiconductor wafer polishing. In the method of the present invention, the retaining ring is lowered to contact the rotating polishing pad, and a cleaning chemistry of ammonium citrate is applied to the pad. In an alternative embodiment, the cleaning chemistry comprises an aqueous solution of ammonium citrate, and a surfactant and/or copper inhibitor. After a sustained preconditioning period in which the retaining ring and polishing pad are polished, the pad is rinsed, lowering particulate buildup on the pad between wafer polishing steps, and bringing defect levels into an equilibrium state prior to each wafer polishing step.

Dependencies are inferred from the claim text.