AVS 61st International Symposium & Exhibition
    Plasma Science and Technology Monday Sessions
       Session PS-MoM

Paper PS-MoM3
Improving Selectivity for 10nm BEOL Etch Using C5HF7 Gas

Monday, November 10, 2014, 9:00 am, Room 308

Session: Current Challenges of Plasma Etching Technologies
Presenter: Robert Bruce, IBM T.J. Watson Research Center
Authors: R.L. Bruce, IBM T.J. Watson Research Center
T. Suzuki, ZEON Chemicals L.P.
M. Nakamura, ZEON Chemicals L.P.
A. Itou, Zeon Corporation
G. Matsuura, Zeon Corporation
S.U. Engelmann, IBM T.J. Watson Research Center
N.P. Marchack, IBM T.J. Watson Research Center
E.M. Sikorski, IBM T.J. Watson Research Center
J. Lee, IBM Albany Nanotech Center
E.A. Joseph, IBM T.J. Watson Research Center
Correspondent: Click to Email
As the industry moves to the 10nm technology node and beyond, new plasma etch challenges arise in the fabrication of back-end-of-line (BEOL) interconnects that need to be overcome. New materials and ever smaller critical dimensions require superior performance in etch, especially in minimizing line-edge roughness and low-k dielectric damage and improving hard mask selectivity. During dual damascene trench etch, low-k plasma damage leads to an increase in dielectric constant and pattern collapse. Also, during the self-aligned via (SAV) etch, vias short between one another due to poor metal hard mask selectivity and merging from via to via. Incorporating C5HF7 gas in these etch processes has shown significant improvements overall, because of its selective deposition properties. However, the C5HF7-based etch process needs to be tuned for the specific application, such as superior TiN selectivity for SAV or SiN selectivity for contact etch. In this talk, the optimized C5HF7-based processes for trench, SAV and contact are reviewed and compared. Furthermore, fundamental learning is accomplished using optical emission spectroscopy and x-ray photoelectron spectroscopy to understand the differences in mechanism between the various process regimes.