Recent progresses on hybrid micro–nano filler systems for electrically conductive adhesives (ECAs) applications

During the last two decades, considerable efforts have been made to explore new generations of interconnecting materials and printed lines to replace the traditionally used toxic lead-based solders in electronic packaging industries. Accordingly, development of electrically conductive adhesives (ECAs) with high electrical conductivity has become an interesting and urgent research venue in this field. Recently, the incorporation of nano-sized conductive fillers inside the conventional formulation of ECAs has drawn considerable attention as an attempt to increase their electrical conductivity. In this article, we review different types of nanofillers that have been utilized inside the conventional ECAs to improve the electrical conductivity of ECAs. We focus on the synergetic effects of silver flakes and the nanofillers on electron transportation through the electrical network; the mechanisms of electrical conductivity enhancement are discussed. Special attention is given to the surface properties of the nanofillers and their corresponding influences on the filler–filler interaction, which has direct effect on the final electrical performance of the hybrid ECAs.