LOCAL REGION ALLOYING FOR PREVENTING COPPER DISHING DURING CHEMICAL/MECHANICAL POLISHING (CMP)

摘要

PROBLEM TO BE SOLVED: To provide a method of planarization with less copper dishing or with no copper dishing in the process of forming a copper interconnection using a damascene process.

SOLUTION: A barrier layer 36 is formed on an insulation film 30 having a trench 32. The trench is filled with a copper layer 38 to a height close to the upper surface 34 of the insulation film. A copper alloy layer 40 is formed on the barrier layer and the copper layer, and a more copper layer can be stacked thereon. A planarized plane 34 is formed by the CMP process. The ratio of the alloy of the copper alloy layer is regulated as the copper alloy layer is polished at a rate equal to that of the barrier layer. Thus, the copper dishing is diminished.

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