United Microelectronics Corp.

J J Huang

Kun-Lin Wu

The present invention provides a method of preventing the dishing phenomenon occurring atop a dual damascene structure on a semiconductor wafer. The semiconductor has a substrate, a first dielectric layer positioned on the substrate, a dual damascene hole positioned in the first dielectric layer through to the surface of the substrate, a barrier layer covering the surface of the first dielectric layer and both the surface of the walls and bottom of the dual damascene hole, and a copper layer positioned on the barrier layer and filling the dual damascene hole to form the dual damascene structure. The method first involves performing a first chemical mechanical polishing (CMP) process to remove portions of the copper layer down to the surface of the barrier layer. A photoresist layer is then formed atop the dual damascene structure to remove portions of the barrier layer uncovered by the photoresist layer. Finally, a second CMP process is performed to remove portions of the copper layer so as to align the top of the copper layer in the dual damascene structure with the surface of the first dielectric layer after the photoresist layer is stripped.

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Hsin-Chu, Taiwan

J J Huang