Microstructure and Electrical Resistivity of Low-Temperature-Cured Silver Films Prepared Using Silver Oxide and Silver Stearate Pastes

Abstract

In this study, paste formulations containing silver oxide coated with a metallo-organic decomposition (MOD) agent of silver stearate were prepared without using any silver powders or silver flakes. Results indicate that all pastes appear to have a pseudoplastic flow property that is acceptable for roll-to-roll printing and screen printing. The pastes were screen-printed on an alumina substrate and then thermally treated in a range of temperatures. The lowest electrical resistivity of 13.2 x 10(-6) Omega.cm was obtained for the film prepared from paste with a Ag(2)O/silver stearate ratio of 100 : 5 at a solid loading of 80 wt % in the solvent a-terpineol, after being cured at 160 degrees C for 5 min, which meets the requirements of low-temperature and high-speed manufacturing for practical applications. The low resistivity of the film is facilitated by the combination of Ag(2)O and silver stearate added to the paste. Ag(2)O produces a high density of silver matrix after being reduced at low temperatures, and the presence of silver stearate contributes to the rheological behavior of the paste after dissolution in the solvent. Coexistence of Ag(2)O and silver stearate induces their simultaneous transformation to the silver form at temperatures below 160 degrees C. (c) 2009 The Japan Society of Applied Physics