Aluminum nitride barrier layer

A method of forming a conformal aluminum nitride layer, the method comprising:

• forming a conformal aluminum nitride layer on a patterned substrate placed in a substrate processing region by:
• i) flowing an organoaluminum precursor into the substrate processing region;
• ii) removing process effluents from substrate processing region;
• iii) flowing a nitrogen-and-hydrogen-containing precursor into the substrate processing region while shining ultraviolet light onto the patterned substrate;
• and
• (iv) removing process effluents from the substrate processing region.

A method of forming a dual-damascene structure, the method comprising:

• forming a conformal silicon carbon nitride layer over a patterned substrate, wherein the patterned substrate comprises a trench and a via below the trench, wherein the via is above an underlying copper layer, wherein sidewalls of the trench and the via comprise low-k dielectric walls, and wherein the trench is fluidly coupled to the via and the conformal silicon carbon nitride layer forms a hermetic seal between the trench and the low-k dielectric walls;
• selectively removing a bottom portion of the conformal silicon carbon nitride layer from the underlying copper layer while retaining a side portion of the conformal silicon carbon nitride layer on the low-k dielectric walls;
• placing the patterned substrate in a substrate processing region;
• i) flowing an aluminum-containing precursor into the substrate processing region
• ii) removing process effluents from substrate processing region;
• iii) flowing a nitrogen-and-hydrogen-containing precursor into the substrate processing region while shining ultraviolet light onto the dual-damascene structure of the patterned substrate;
• and
• iv) removing process effluents from the substrate processing region.