Sintering mechanism of electronic aluminum paste and its effect on electrical conductivity of aluminum electrode

Abstract

In view of the wide application of aluminum paste in the manufacture of electronic devices, it is important to thorough understanding and accurate control of the factors affecting electrical conductivity of aluminum electrodes and the related mechanisms. In this paper, we investigate the microstructural evolution of aluminum paste during sintering and analyze the effects of process parameters such as glass type and temperature on electrical conductivity of aluminum electrodes. The results demonstrate that differences in sintering temperature, glass type and content cause significant changes in the structural compactness and electrical conductivity of aluminum electrodes. At a certain temperature, part of the aluminum oxide film will break or peel off due to the difference in thermal expansion between aluminum particles and oxide film. At the same time, the melt glass has a certain fusion effect on the aluminum oxide film on the surface of the aluminum powder. The combined effect of these two factors can cause damage, thinning, peeling or removal of the oxide film on the surface of the aluminum powder, so that more conductive contact points (surfaces) are formed at the interface between the aluminum powder particles, and as a consequence, a coherent conductive network microstructure is formed at the aluminum electrode. With the increase of glass content in aluminum paste, the square resistance of aluminum electrode first decreases and then increases. Results of the study will provide reference for further study and application of electronic aluminum paste.