Patent ID: 7713866

Claim:
A method of forming a barrier layer, the method comprising: providing a workpiece having a silicide material layer; forming a first insulating material layer of a first metallization level over the silicide material layer; forming a second insulating material layer of a second metallization level over the first insulating material layer, wherein the first and the second metallization levels comprise a metal or via level above the workpiece; forming a trench in the first and the second insulating material layers, a bottom surface of the trench exposing the silicide material layer; forming a mono-layer of HfN (hafnium nitride) lining the trench and in contact with the exposed silicide material layer; forming a metal nitride layer over the HfN mono-layer, wherein forming the metal nitride layer comprises forming a TaN or TiN layer in contact with said HfN mono-layer; forming a metal layer over and in contact with the metal nitride layer, the metal layer comprising Ta or Ti, wherein the barrier layer comprises the HfN mono-layer, the metal layer and the metal nitride layer; and exposing the silicide material layer by removing the barrier layer from the bottom surface of the trench; after exposing the silicide material layer, lining the metal layer with a conductive liner; and filling the trench by depositing a conductive fill material on the conductive liner.