Method of reducing dishing and erosion using a sacrificial layer

摘要

Chemical mechanical polishing (CMP) is known to cause dishing when the surface being planarized includes a wide trench partially filled with metal. This problem has been overcome by first filling the trench with a material whose polishing rate under CMP is similar to that of the metal in the trench. Spin-coating is used for this so that only the trench gets filled. After CMP, any residue of this material is removed, leaving behind a surface that has been planarized to the intended extent without the introduction of significant dishing and with minimum erosion of the metal.