title: Direct-Liquid-Evaporation Chemical Vapor Deposition of Nanocrystalline Cobalt Metal for Nanoscale Copper Interconnect Encapsulation.
abstract: In advanced microelectronics, precise design of liner and capping layers become critical, especially when it comes to the fabrication of Cu interconnects with dimensions lower than its mean free path. Herein, we demonstrate that direct-liquid-evaporation chemical vapor deposition (DLE-CVD) of Co is a promising method to make liner and capping layers for nanoscale Cu interconnects. DLE-CVD makes pure, smooth, nanocrystalline, and highly conformal Co films with highly controllable growth characteristics. This process allows full Co encapsulation of nanoscale Cu interconnects, thus stabilizing Cu against diffusion and electromigration. Electrical measurements and high-resolution elemental imaging studies show that the DLE-CVD Co encapsulation layer can improve the reliability and thermal stability of Cu interconnects. Also, with the high conductivity of Co, the DLE-CVD Co encapsulation layer have the potential to further decrease the power consumption of nanoscale Cu interconnects, paving the way for Cu interconnects with higher efficiency in future high-end microelectronics.
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States.
authors.forename: Jun
authors.identifier: http://orcid.org/0000-0001-5730-3844
authors.initials: J
authors.lastname: Feng
authors.affiliation: John A. Paulson School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States.
authors.forename: Xian
authors.identifier: http://orcid.org/0000-0003-4570-8080
authors.initials: X
authors.lastname: Gong
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States.
authors.forename: Xiabing
authors.identifier: http://orcid.org/0000-0003-4402-3207
authors.initials: X
authors.lastname: Lou
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States.|John A. Paulson School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States.
authors.forename: Roy G
authors.identifier: http://orcid.org/0000-0001-5980-268X
authors.initials: RG
authors.lastname: Gordon
keywords: DLE-CVD; cobalt; copper encapsulation; metal interconnect; nanocrystalline