Nucleation and Adhesion of ALD Copper on Cobalt Adhesion Layers and Tungsten Nitride Diffusion Barriers

Electrochem. Solid-State Lett., Volume 8, Issue 7, pp. G182-G185 (2005)

(Published 24 May 2005)

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ABSTRACT

REFERENCES (18)

CITING ARTICLES

Zhengwen Li,¹ Roy G. Gordon,¹ Damon B. Farmer,² Youbo Lin,² and Joost Vlassak²
¹Department of Chemistry and Chemical Biology and
²Division of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA

Atomiclayer deposition (ALD) was used to make conformal diffusion barrierlayers of WN, adhesion layers of Co, and seed layersof Cu. Transmission electron microscopy and atomic force microscopy wereused to study the nucleation of these layers. WN andCo nucleated uniformly as continuous layers. Cu nucleated as discontinuousislands on SiO₂, Si₃N₄, and WN, but as a continuous,nanocrystalline layer on Co/WN. Electrical continuity was found for Cu/Colayers with a thickness under 2 nm. Extremely strong adhesion(>31 J/m²) was measured for the Cu/Co/WN/SiO₂ structure, more than fivetimes higher than the Cu/Ta/TaN_x/SiO₂ structures currently used for interconnects.

©2005 The Electrochemical Society

History:	Submitted 25 February 2005; revised 28 March 2005; published 24 May 2005
Permalink:	http://dx.doi.org/10.1149/1.1924929

KEYWORDS and PACS

Keywords

copper, cobalt, tungsten compounds, metallic thin films, nucleation, adhesion, atomic layer deposition, diffusion barriers, transmission electron microscopy, atomic force microscopy, integrated circuit interconnections

PACS

68.55.Ac
Thin film nucleation and growth: microscopic aspects
81.15.Gh
Chemical vapor deposition including plasma-enhanced CVD, MOCVD, etc
66.30.-h
Diffusion in solids
68.35.Fx
Diffusion; interface formation (solid surfaces)
68.37.Ps
Atomic force microscopy (AFM) of surfaces, interfaces and thin films
68.37.Lp
Transmission electron microscopy (TEM) of surfaces, interfaces and thin films including STEM, HRTEM, etc
YEAR: 2005