Patent ID: 6440857
Filing Date: 2002-08-27
Classification: C09G,H01L

Abstract:
A two-step CMP method for planarizing a wafer surface, said wafer surface contains an aluminum containing metal layer and a Ti/TiN barrier layer, said method comprising steps of:(A) polishing said metal layer in a first polishing slurry, said first polishing slurry comprising an abrasive, a pH buffer, a metal polishing promoter, an oxidant, and deionized water; and (B) polishing said barrier layer in a second polishing slurry, said second polishing slurry comprising an abrasive, a pH buffer, a dielectric layer protector, an oxidant, and deionized water; and wherein said first polishing slurry in said step (A) comprises 30-99 wt. % deionized water, 0.5-60 wt. % abrasive, 0.01-10 wt. % metal polishing promoter, and 0.1-30 wt. % oxidant; and wherein said second polishing slurry in said step (B) comprises 30-99 wt. % deionized water, 0.5-60 wt. % abrasive, 0.01-10 wt. % dielectric layer protector, and 0.1-30 wt. % oxidant, and having a pH value between 2.0 and 7.0.