Fabrication of conductive interconnects by Ag migration in Cu-Ag core-shell nanoparticles

Suk Jun Kim, Purdue University - Main Campus
E A. Stach, Birck Nanotechnology Center and School of Materials Engineering, Purdue University
Carol A. Handwerker, Purdue University - Main Campus

Abstract

Fabrication of conductive nanoparticle films is observed in Cu-Ag core-shell nanoparticles by fast diffusion of Ag at 220 degrees C from particle surfaces, leading to the formation of sintered necks of Ag at the initial particle-particle contacts. Transmission electron microscopy showed that the necks were pure Ag and that particle surfaces away from the contacts were nearly Ag-free. The extent of neck formation is controllable by the choice of initial Ag thickness. Analysis of the thermodynamics of the Ag-Cu system and the relative diffusivities of Ag and Cu provide criteria for fabrication of other core-shell two-phase systems by the same mechanism.

Discipline(s)

Engineering | Nanoscience and Nanotechnology