Thin and planar copper layers for advanced interconnect fabrication

A novel planarization process was evaluated by integrating electrochemical mechanical polishing (eCMP) capability on copper plating platform. In the integrated system, the wafer is electroplated and then transferred to the planarization module where the bulk of copper is polished and planarized at high rate leaving a thin and a planar copper film. The polishing rate is controlled by the applied current density. The resulting planar thin film coming from the plating tool enables conventional chemical mechanical polishing to clear the remaining copper and barrier with low dishing and erosion. This paper presents data on the attributes of the planarization process step as well as the electrical and dishing data obtained from wafers with planar copper overburden of thickness ranging from 2k angstrom to 5k angstrom.