Copper nanoparticles generated in situ in imidazolium based ionic liquids

Copper nanoparticles (CuNPs) have been successfully synthesized in imidazolium based ionic liquid (IL) under mild conditions. In this self-ordered medium, particles with narrow size distribution can be formed. No ligand is required to stabilize the suspension, which can be directly used to coat technological substrates. Several parameters are examined: the nature of IL, stirring, dihydrogen pressure and temperature. Under optimal conditions, well dispersed, zero-valent CuNPs of 4.5 nm with narrow size distribution are obtained. These stable suspension of Cu(0)NPs is a promising starting material to form conformal copper seed layers in high aspect ratio interconnect structures. (C) 2010 Elsevier By. All rights reserved.