US Patent 7521379 Deposition and densification process for titanium nitride barrier layers

In one embodiment, a method for forming a titanium nitride barrier material on a substrate is provided which includes depositing a titanium nitride layer on the substrate by a metal-organic chemical vapor deposition (MOCVD) process, and thereafter, densifying the titanium nitride layer by exposing the substrate to a plasma process. In one example, the MOCVD process and the densifying plasma process is repeated to form a barrier stack by depositing a second titanium nitride layer on the first titanium nitride layer. In another example, a third titanium nitride layer is deposited on the second titanium nitride layer. Subsequently, the method provides depositing a conductive material on the substrate and exposing the substrate to a annealing process. In one example, each titanium nitride layer may have a thickness of about 15 Å and the titanium nitride barrier stack may have a copper diffusion potential of less than about 5×1010 atoms/cm2.