Influence of Curing Procedures on the Electrical Properties of Epoxy-Based Isotropic Conductive Adhesives

Abstract:

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 the different curing procedures on the electrical properties of the ICAs were investigated. The results showed that there is greater influence of the curing temperature on 55 wt % silver loading, the volume resistivity of ICAs decreased to 4.5 ×10-3 from 5.2×10-2 cured at 250 0C and 180 0C, respectively. However, there is almost no effect on the high silver loading. The in situ monitoring the variations in electrical resistance of the ICAs with 65 wt % silver loading was studied during the curing process, and it was found that the resistance reached to 1.99 ×106 Ω at 180 0C after cured for 27 min, and reached to 1.39 ×10-3 Ω for 40 min, and 18.8 Ω for 60 min and the cooling process has almost no effect on the electrical resistance of the ICAs. The reasons for the dependence of the bulk resistivity on temperatures were also discussed in terms of the dispersing of the silver flakes in ICAs by SEM.