Abstract: A CMP slurry for and method of polishing a semiconductor wafer during formation of metal interconnects are disclosed. The present invention utilizes a first slurry comprising a first oxidizer, preferably ferric nitrate, to remove the excess metal of the metal interconnect but which leaves the metal residues on the surface of the wafer. A second slurry comprising another oxidizer, preferably potassium iodate solution, having a greater affinity to both the metal residue and the liner material than the underlying dielectric is used to remove the metal residue and liner material with significantly reduced scratching of the underlying dielectric. The more robust metal interconnects formed utilizing the present invention is effective in lowering the overall resistance of a wafer, reducing the number of shorts, and provides greater protection of the underlying dielectric. Overpolishing of the wafer and its associated problems are avoided.

Abstract: An apparatus for polishing a semiconductor wafer is provided which includes a wafer carrier having on its lower surface a non-uniform surface structure means to vary the force against a wafer during a polishing operation so that the polishing is enhanced and imparts a planar surface across the polished wafer. Preferred non-uniform surface structure means include use of a wafer carrier having on its lower surface a backing film having a first central portion having a predetermined compressibility and a second peripheral portion having a different compressibility than the first portion. Another non-uniform surface structure means to vary the force against the wafer comprises a wafer carrier having on its lower surface a raised circumferential region around the periphery of the carrier.