Cobalt resistance recovery by hydrogen anneal

摘要

Resistance increase in Cobalt interconnects due to nitridation occurring during removal of surface oxide from Cobalt interconnects and deposition of Nitrogen-containing film on Cobalt interconnects is solved by a Hydrogen thermal anneal or plasma treatment. Removal of the Nitrogen is through a thin overlying layer which may be a dielectric barrier layer or an etch stop layer.

主权项

1. A method of processing a workpiece, comprising:
forming on the workpiece a dielectric layer and an interlayer conductive interconnect extending through said dielectric layer; removing oxide from an exposed surface of said interlayer conductive interconnect by treating said workpiece in a plasma formed of a Nitrogen-containing gas, to form a Nitrogen-containing surface zone in said interlayer conductive interconnect and leaving in place said Nitrogen-containing surface zone as a silicidation-preventing layer; depositing on said interlayer conductive interconnect a Silicon-containing dielectric barrier layer of a thickness less than a threshold thickness; reducing electrical resistance of said interlayer conductive interconnect by removing Nitrogen from said interlayer conductive interconnect through said dielectric barrier layer; and increasing thickness of said dielectric barrier layer above said threshold thickness.