Spray and Inkjet Printing of Hybrid Nanoparticle-Metal-Organic Inks for Ag and Cu Metallizations

Metal-organic and hybrid metal-organic/metal nanoparticle inks were evaluated for use in the inkjet printing of copper and silver conducting lines. Pure, smooth, dense, highly conductive coatings were produced by spray printing with (hexafluoroacetylacetonato)copper(I)-vinyltrimethylsilane (Cu(hfa)•VTMS) and (hexafluoroacetylacetonato)silver(I)(1,5-cyclooctadiene) (Ag(hfa)COD) metal-organic precursors on heated substrates. Good adhesion to the substrates tested, glass, Kapton tape and Si, has been achieved without use of adhesion promoters. The silver metal-organic ink has also been used to print metal lines and patterns with a commercial inkjet printer. Hybrid inks comprised of metal nanoparticles mixed with the metal-organic complexes above have also been used to deposit Cu and Ag films by spray printing. This approach gives dense, adherent films that are much thicker than those obtained using the metal-organic inks alone. The conductivities of the silver coatings obtained by both approaches are near that of bulk silver (2 μΩ•cm). The copper coatings had conductivities at least an order of magnitude less than bulk.