ABSTRACT
Cu Chemical-mechanical planarization (CMP) slurries commonly use submicron-sized colloidal silica abrasive particles dispersed in aqueous solutions that contain an oxidizer, as well as a complexing agent and corrosion inhibiting agents and other chemicals. The pH value of the polishing slurry is one of the most important parameters influencing the polishing rate, surface roughness, and other performance characteristics of the Cu CMP process. The CMP is used to planarize the barrier metal, low-k, and copper layer following their deposition process. Dishing of copper lines is among the most important issues of copper CMP. Cu electropolishing technology has been explored as a replacement of the Cu CMP planarization process. The traditional Cu CMP process includes step-height reduction of wiring metal and removal of overburden metal outside the features. The amount of Cu dishing and erosion after Cu CMP was found to increase with the increases of Cu pad size and overpolish time.
