Room-Temperature Sintering Process of Ag Nanoparticle Paste

Recently, the authors developed a novel room-temperature wiring method using Ag nanoparticle paste. In this paper, the sintering mechanism of the Ag nanoparticle paste was clarified through examination of the adsorption stability and the removal of the dispersant from the Ag nanoparticles. The Ag nanoparticles in the paste are protected by dodecylamine as a dispersant. This paste possesses substantially long shelf life and thermo stability at room temperature. When the printed line of the Ag nanoparticle paste is dipped in a methanol bath, methanol effectively dissolves and removes the dispersant from the nanoparticles. Ag nanoparticles are sintered within a short period. The sintering of Ag nanoparticles is not uniform. Some Ag nanoparticles quickly grow and form a network by sintering (necking). The others maintain a nanometer scale. Large Ag particles and an Ag skeleton continue to grow by absorbing very small nanoparticles. In addition, the use of ethanol and isopropanol as the treatment agent is shown for the first time.