Influence of curing procedures on the electrical properties of epoxy-based isotropic conductive adhesives

In this paper, a typical isotropic conductive adhesives (ICAs) composed of an epoxy-based binder containing micro-sized silver flakes was prepared and the effects of different curing procedures on the electrical properties of conductive adhesives were investigated. The results showed that there a greater influence of the curing temperature on 55% silver fill loading, the volume resistivity of ICAs decreased to 4.7×10-from 1.0×10^-3 cured at 180 °C and 250 °C, respectively. However, there is almost no effect on the high silver fill loading. The in situ monitoring the variations in electrical resistance of ICAs with 65% silver fill loading was studied during the curing process, and it was found that the resistance reached to 1.99 MΩ at 180 °C after cured for 27 min, and reached to 1.39 KΩ for 40 min, and 18.8 Ω for 60 min and the cooling process almost no effect on the electrical resistance of ICAs. The reasons for the dependence of bulk resistivity on temperatures were also discussed in terms of the dispersing of the silver flakes in ICAs by SEM.