• DOI:10.1063/1.117953
• Corpus ID: 97519992

Gas‐phase transport of WF6 through annular nanopipes in TiN during chemical vapor deposition of W on TiN/Ti/SiO2 structures for integrated circuit fabrication

@article{Ramanath1996GasphaseTO,
  title={Gas‐phase transport of WF6 through annular nanopipes in TiN during chemical vapor deposition of W on TiN/Ti/SiO2 structures for integrated circuit fabrication},
  author={Ganapathiraman Ramanath and J. R. A. Carlsson and Joseph E. Greene and Leslie H. Allen and Verne Hornback and Derryl D. J. Allman},
  journal={Applied Physics Letters},
  year={1996},
  volume={69},
  pages={3179-3181}
}

• G. Ramanath, J. Carlsson, +3 authors D. Allman
• Published 1 November 1996
• Physics
• Applied Physics Letters

Delamination of TiN/Ti bilayers on SiO2 is a serious problem during W chemical vapor deposition (CVD) using WF6 to form vertical interconnects in integrated circuits. In order to obtain insight into the delamination mechanism, we have determined depth‐distributions of W and F in sputter‐deposited TiN/Ti bilayers on SiO2 as a function of WF6 exposure time tWF6 at 445 °C. Even for tWF6<6 s, significant concentrations of both W (≊3.5 at. %) and F (≊2 at. %) penetrate through the 106‐nm‐thick TiN film. W piles up at the TiN/Ti interface, while F rapidly saturates the TiN layer and accumulates in the Ti underlayer at concentrations up to ≊10 at. % for tWF6=60 s. Cross‐sectional and scanning transmission electron microscopy analyses demonstrate that WF6 penetrates into the TiN layer through nanometer‐scale intercolumnar voids spanning the entire film thickness and reacts with the Ti underlayer. We propose that the high F concentrations in the Ti layer weakens the Ti/SiO2 interface leading to adhesion failure of...