Method to improve a copper/dielectric interface in semiconductor devices

1. A method of incorporating phosphorus in a device structure, the method comprising:

planarizing a top surface of a workpiece to create a substantially planar surface comprising a plurality of conductive paths and a plurality of dielectric regions;

depositing a barrier layer over the substantially planar surface thereby forming an interface between the substantially planar surface and the barrier layer; and

doping at least a portion of the barrier layer adjacent the interface with phosphorus to form a phosphorus-doped barrier layer and to provide phosphorus dopant at least at the interface between the substantially planar surface and the barrier layer,

wherein the doping is performed after the depositing, and includes infusing the phosphorus into the barrier layer, the plurality of dielectric regions, and the plurality of conductive paths using a gas cluster ion beam to getter metal contaminants in the dielectric regions and to minimize electromigration in the conductive paths.

2. The method of claim 1 , wherein the barrier layer is selected from the group consisting of silicon nitride, silicon carbide, nitrogen doped silicon carbide, boron carbon nitride, and boron nitride.

3. The method of claim 2 , wherein a thickness of the barrier layer is approximately between 20 angstroms and 200 angstroms.

4. The method of claim 1 , further including a pre-treatment to modify or remove a portion of material from the planarized top surface.

5. The method of claim 1 , further including a pre-treatment to remove contaminants from the planarized top surface.

6. The method of claim 1 , wherein the phosphorus-doped barrier layer contains between 0.1 atomic % and 10 atomic % phosphorus.

7. The method of claim 1 , wherein a thickness of the barrier layer is approximately between 5 angstroms and 20 angstroms.