CMP method for suppression of titanium nitride and titanium/titanium nitride removal

A chemical mechanical polishing (CMP) method of polishing a substrate comprising a metal deposited over a titanium nitride (TiN) or titanium/titanium nitride (Ti/TiN) barrier layer;

• the method comprising contacting the substrate with an acidic CMP composition comprising a particulate abrasive suspended in a liquid carrier, wherein the particulate abrasive comprises alumina, and has a mean particle size of about 10 to about 150 nm, the liquid carrier comprising a surfactant, wherein the surfactant comprises a mixture of (C10-C14) alkylbenzene and ethoxylated (C6-C12) alcohols, wherein the surfactant suppresses a rate at which the TiN and Ti/TiN is polished, and wherein pH of the composition is in the range of about 2 to about 5.