Lower limits of line resistance in nanocrystalline back end of line Cu interconnects

The strong non-linear increase in theCuinterconnect lineresistance with decreasing linewidth presents a significant obstacle to their continued downscaling. In this letter we use the first principlesdensity functional theory based electronic structure ofCuinterconnects to find the lower limits of their lineresistance for metal linewidths corresponding to future technology nodes. We find that even in the absence of scattering due tograin boundaries, edge roughness or interfaces, quantum confinement causes a severe increase in the lineresistance ofCu. We also find that when the simplest scattering mechanism in thegrain boundary scattering dominated limit is added to otherwise coherent electronic transmission in monocrystallinenanowires, the lower limit of lineresistance is significantly higher than projected roadmap requirements in the International Technology Roadmap for Semiconductors.

Source: Applied Physics Letters - November 7, 2016 Category: Physics Authors: Ganesh Hegde, R. Chris Bowen and Mark S. Rodder Source Type: research