This book (Practical Electron Microscopy and Database) is a reference for TEM and SEM students, operators, engineers, technicians, managers, and researchers.
Figure 2905 shows cross-sectional schematic illustration of Cu (copper) single damascene interconnects with Ta barrier and dielectric diffusion barrier SiCxNy.
Figure 2905. Cross-sectional schematic illustration of Cu single damascene interconnects with Ta barrier and dielectric diffusion barrier SiCxNy.
An activation energy (Ea) of ~ 0.9 eV is obtained for the Cu width range of 0.1–6 µm when the dielectric diffusion barrier is SiCxNy. 
In this case, the interface between Cu and SiCxNy is the dominant diffusion path for the Cu damascene interconnects regardless of the Cu microstructure (either bamboolike or polycrystalline structures). Note that the Ea of grain-boundary diffusion of electroplated Cu is 1.08 eV. 
 T. Usui, H. Nasu, T. Watanabe, H. Shibata, T. Oki, and M. Hatano, Electromigration diffusion mechanism of electroplated copper and cold/hot two-step sputter-deposited aluminum-0.5-wt% copper damascene interconnects, Journal of Applied Physics 98, 063509 (2005).
 D. Gan, P. S. Ho, R. Huang, J. Leu, J. Maiz, and T. Scherban, J. Appl.
Phys. 97, 103531 (2005).