Method of forming interconnects with improved barrier layer adhesion

Abstract

Semiconductor devices comprising interconnects with improved adhesion of barrier layers to dielectric layers are formed by laser thermal annealing, in N2 and H2, exposed surfaces of a dielectric layer defining an opening, and then depositing Ta to form a composite layer lining the opening. Embodiments include forming a dual damascene opening in an interlayer dielectric comprising F-containing dielectric material, such as F-silicon oxide derived from F-TEOS, impinging a pulsed laser light beam on exposed surfaces of the F-silicon oxide defining the opening in a flow of N2 and H2, and then depositing Ta to form a composite barrier layer comprising graded tantalum nitride and α-Ta lining the opening. Laser thermal annealing in N2 and H2 depletes the exposed silicon oxide surfaces of F while enriching the surfaces with N2. Deposited Ta reacts with the N2 in the N2-enriched surface region to form a composite barrier layer comprising a graded layer of tantalum nitride and a layer of α-Ta thereon. Cu is then deposited, CMP conducted and a capping layer deposited to form the dual damascene structure.

Dependencies are inferred from the claim text.