| 摘要 |
The dishing of copper during chemical mechanical polishing (CMP) process can be significantly reduced, and in most instances eliminated, by the use of electroplated alloys of copper whereas the alloying metal forms a continuous solid solution with the copper. A deposition layer of such an alloy allows for lowering the selectivity of the slurry polish used during the CMP process towards the alloy, allowing the alloy layer and barrier layer to be polished at an equivalent rate until the entire barrier layer has been polished. In this manner, dishing of the copper in the trenches of a wafer from the CMP process can be avoided. Deposited in a recessed portion 32 of a substrate wafer 30 is a barrier layer 36, a copper layer 38, then a copper alloy layer 40, and optionally a final copper layer 44. The CMP process removes the copper layer 44, then polishes the copper alloy layer 40 and barrier layer 36 at substantially the same rate, forming a planar surface on the substrate. |
