Influence of Reductant Concentration on the Conduction Path Formation Properties of Solderable Polymer Composites

Abstract

When solderable polymer composites (SPCs) filled with a low-melting-point-alloy (LMPA) was used in the bonding process, the elimination of surface oxide layers of the fillers and electrodes is very important to achieve an excellent conduction path by the proper coalescence-wetting behaviors of molten fillers. In this study, to investigate the influence of reductant content on the conduction path formation, four kinds of SPC with different reductant amounts (0, 7.5, 15, and 30 phr) were examined. The LMPA filler with a reductant concentration of 15 phr exhibits excellent wettability because of the proper elimination of the surface oxide layer of fillers and electrodes. However, the wettability deteriorated with a further increased reductant content due to the rapid curing of the SPC at low temperature conditions caused by increased chemical reactions between the carboxyl groups of the reductant and epoxide groups.