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First-principles simulations of the reactivity of barrier layers of Ti, Ta and W and their nitrides towards precursors for CVD copper deposition

Pablo Ordejon 2Eduardo Machado 2Marcin Kaczmarski 2Benoît Braida 2,3Eduardo Hernandez 2Hansong Cheng 1Diwakar Garg 1John A. Norman 1

1. Computational Modeling Center, Corporate Science and Technology Center and Schumacher, Air Products and Chemicals, Inc., 7201 Hamilton Boulevard, Allentown, PA 18195, United States
2. Instituto de Ciencia de Materiales de Barcelona, CSIC (ICMAB), Campus UAB, Barcelona 08193, Spain
3. CNRS - Laboratoire de Chimie Theorique, Université Pierre et Marie Curie, 4 Place Jussieu, Paris 75252, France

Abstract

We present first-principles Density Functional Theory calculations of the reactivity of Ti, Ta and W surfaces and their nitrides with Cu-hexafluoracetylacetonato-trimethylvinylsilane [Cu(hfac)(tmvs)], a chemical precursor used for CVD growth of copper films. We show that the surfaces of the pure refractory metals are highly reac-tive, and that the copper precursor decomposes spontaneously upon contact with the surface. The products of the decomposition attach strongly to the surface, forming fluorine, carbon and oxygen containing layer on the surface that may lower the effi-ciency of the copper deposition and the adherence of the copper layer. For the case of the metal nitrides, those surfaces prepared with an orientation such that no refractory metal atom is exposed to the surface do not show such reactivity, with the copper precursor staying intact upon interaction with the surface. Our simulations suggest strategies for improved deposition efficiency and adhesion properties of copper films deposited by CVD on refractory metal barrier layers.

 

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Presentation: oral at E-MRS Fall Meeting 2004, Symposium I, by Pablo Ordejon
See On-line Journal of E-MRS Fall Meeting 2004

Submitted: 2004-04-27 23:57
Revised:   2009-06-08 12:55