Gas-phase transport of WF{sub 6} through annular nanopipes in TiN during chemical vapor deposition of W on TiN/Ti/SiO{sub 2} structures for integrated circuit fabrication

Journal Article · Fri Nov 01 00:00:00 EST 1996 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.117953· OSTI ID:389248

Ramanath, G; Carlsson, J R; Greene, J E; Allen, L H ^[1]; Hornback, V C; Allman, D J ^[2]

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1. Coordinated Science Laboratory, Materials Research Laboratory, and Department of Materials Science, University of Illinois, 1304 W. Green Street, Urbana, Illinois 61801 (United States)
2. Symbios Logic Inc., 1635 Aeroplaza Drive, Colorado Springs, Colorado 80916 (United States)

Delamination of TiN/Ti bilayers on SiO{sub 2} is a serious problem during W chemical vapor deposition (CVD) using WF{sub 6} 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 SiO{sub 2} as a function of WF{sub 6} exposure time {ital t}{sub WF{sub 6}} at 445{degree}C. Even for {ital t}{sub WF{sub 6}}{lt}6 s, significant concentrations of both W ({approx_equal}3.5 at.{percent}) and F ({approx_equal}2 at.{percent}) 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 {approx_equal}10 at.{percent} for {ital t}{sub WF{sub 6}}=60 s. Cross-sectional and scanning transmission electron microscopy analyses demonstrate that WF{sub 6} 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/SiO{sub 2} interface leading to adhesion failure of the TiN/Ti bilayer. {copyright} {ital 1996 American Institute of Physics.}

• Research Organization: Univ. of Illinois at Urbana-Champaign, IL (United States)
• DOE Contract Number: AC02-76ER01198
• OSTI ID: 389248
• Journal Information: Applied Physics Letters, Vol. 69, Issue 21; Other Information: PBD: Nov 1996
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
TUNGSTEN
CHEMICAL VAPOR DEPOSITION
TITANIUM NITRIDES
ADHESION
TITANIUM
INTERFACES
SILICON OXIDES
ALKYLATING AGENTS
INTEGRATED CIRCUITS
THIN FILMS
VOIDS
CONNECTORS
CVD