INTERCONNECTS WITH IMPROVED BARRIER LAYER ADHESION

摘要

Semiconductor devices comprising interconnect with improved adhesion of barrier layers to dielectric layers are formed by laser thermal annealing exposed surfaces of a dielectric layer in an atmosphere of NH3 and N2, and subsequently depositing Ta to form a composite barrier layer. Embodiments include forming a dual damascene opening in an interlayer dielectric comprising F-containing silicon oxide, such as F-containing silicon oxide derived from F-TEOS, laser thermal annealing the exposed silicon oxide surface in NH3 and N2, depositing Ta and then filling the opening with Cu. Laser thermal annealing in NH3 and N 2 depletes the exposed silicon oxide surface of F while forming an N2-rich surface region. Deposited Ta reacts with the N2 om the N2-rich surface region to form a composite barrier layer comprising a graded layer of tantalum nitride and a layer ofα-Ta thereon.