Selective polish process for titanium, titanium nitride, tantalum and tantalum nitride

摘要

An improved Chemical Mechanical Planarization (CMP) method is provided for selectively removing a layer of metallization material such as tungsten or copper and a liner film such as Ti/Tin or Ta/TaN from the surface of an oxide layer of a semiconductor wafer. The method includes removing the metallization and liner layers with a first removal process which utilizes CMP polishing and an alumina-based slurry. The first removal process is stopped after the metallization layer is completely removed and before the liner film is completely removed. The remainder of the liner film is removed using a second removal process which includes CMP polishing using a neutral pH silica-based slurry which is selective to the liner film.