1. Inhomogeneous nucleation and growth of palladium and alloyed cobalt during self-aligned capping of advanced copper interconnects
- Author
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Tifenn Decorps, Maria-Luisa Calvo-Muñoz, Ségolène Olivier, Paul-Henri Haumesser, Sandrine Da Silva, Gérard Passemard, and Cyril Cayron
- Subjects
Materials science ,Cobalt alloys ,Nucleation ,chemistry.chemical_element ,Electrons ,Substrate (electronics) ,Backscattering ,Epitaxy ,Polycrystalline copper ,Nucleation densities ,Atomic force microscopy ,Epitaxial relationships ,Electroless deposition ,Materials Chemistry ,Epitaxial growth ,Wafer ,Composite material ,Cobalt compounds ,Nucleation and growth ,Metals and Alloys ,Copper substrates ,Electron back scatter diffraction ,Cobalt ,Surfaces and Interfaces ,Inhomogeneities ,300 mm wafers ,Copper ,TEM characterization ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Crystallography ,chemistry ,Electron diffraction ,Transmission electron microscopy ,Self-aligned ,Substrate orientation ,Thickness variation ,Deposits ,Transmission electron ,Diffraction ,Palladium ,Copper interconnects - Abstract
We investigate the nucleation and growth of two cobalt alloys (CoWB and Pd-CoWP) used to encapsulate copper interconnects. We demonstrate that very uniform deposits are obtained across 300 mm wafers, with accurate thickness control. However, large local thickness variations are observed, possibly compromising the continuity of thin deposits. The origin of this phenomenon is first investigated by electron back scatter diffraction. A clear correlation between areas of dense Pd nucleation and the (111) grains of the polycrystalline copper surface is demonstrated. Then, an epitaxial relationship between the cobalt alloys and the underlying copper substrate is evidenced by TEM characterization. Local nucleation density could thus be affected by the substrate orientation, accounting for thickness inhomogeneities after growth. © 2010 Elsevier B.V. All rights reserved.
- Published
- 2010
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