In-situ pad and wafer cleaning during chemical mechanical polishing

摘要

A method for in-situ cleaning a polishing pad and a wafer surface simultaneously during copper chemical mechanical polishing and an apparatus for carrying out such method are disclosed. The method is carried out by dispensing an acid-containing solution onto a top surface of a polishing pad while the wafer is rotated against the polishing pad without any slurry solution being dispensed. The acid-containing solution may be advantageously formed by diluting an acid such as citric acid, HCOOH, CH3COOH, HNO3, H2SO4 and HF to a concentration of less than 10 wt. % acid, preferably less than 5 wt. % acid, and more preferably less than 1 wt. % acid. The acid-containing solution may be dispensed onto a top surface of the polishing pad for a time period between about 30 sec. and about 300 sec.