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 N2 depletes the exposed silicon oxide surface of F while forming an N2-rich surface region. Deposited Ta reacts with the N2 in the N2-rich surface region to form a composite barrier layer comprising a graded layer of tantalum nitride and a layer of alpha-Ta thereon.