Chemical mechanical polishing (CMP) slurry for polishing copper interconnects which use tantalum-based barrier layers

摘要

A method for forming a copper interconnect on an integrated circuit (IC) begins by forming a dielectric layer (20) having an opening. A tantalum-based barrier layer (21), such as TaN or TaSiN, is formed within the opening in the layer (20). A copper layer (22) is formed over the barrier layer (21). A first CMP process is used to polish the copper (22) to expose portions of the barrier (21). A second CMP process which is different from the first CMP process is then used to polish exposed portions of the layer (21) faster than the dielectric layer (20) or the copper layer (22). After this two-step CMP process, a copper interconnect having a tantalum-based barrier is formed across the integrated circuit substrate (12).