Sinterability and conductivity of silver paste with Pb-free frit

Abstract

Abstract Conductive silver paste for low sintering temperature was prepared by mixing two commercial silver powders with different particle size of 0.8 μm and 1.6 μm, and nanoparticles of 20–50 nm. The silver nanoparticles were synthesized by a chemical reduction method using surfactant and 10 wt% of the nanoparticles was added as a low sintering temperature aid. About 3, 6 and 9 wt% of Pb-free frits were added to the mixed silver powder, respectively. Using the paste, thick films were prepared by a screen-printing on an alumina substrate and the films were sintered at temperatures from 400 to 550 °C. As increasing the sintering temperatures and glass frit contents, the thick films became dense and their sheet resistivity decreased corresponding to dense microstructure. The films had thickness of 4–6 μm and sheet resistivity of approximately 5–10 mΩ/□.