Patent ID: 7838441

Claim:
A method for forming a titanium nitride barrier stack on a substrate, comprising: depositing a first titanium nitride layer on the substrate by a metal-organic chemical vapor deposition process; exposing the first titanium nitride layer to a plasma to form a first densified titanium nitride layer thereon; depositing a second titanium nitride layer on the first densified titanium nitride layer by the metal-organic chemical vapor deposition process; exposing the second titanium nitride layer to the plasma to form a second densified titanium nitride layer thereon; depositing a third titanium nitride layer on the second densified titanium nitride layer by the metal-organic chemical vapor deposition process; exposing the third titanium nitride layer to the plasma to form a third densified titanium nitride layer thereon; depositing a conductive material on the substrate; and exposing the substrate to an annealing process, wherein the titanium nitride barrier stack has a copper diffusion of less than about 5×10 10 atoms/cm 2 .