Electrical properties of electrically conductive adhesives from epoxy and silver-coated copper powders after sintering and thermal aging

Abstract

In order to enhance the oxidation resistance of a copper substrate, silver films were deposited by three-times electroless plating onto pure copper powders. Silver-coated copper (Ag/Cu) powders were introduced into electrically conductive adhesives (ECAs) as conductive fillers. The electrical conductivity of the ECAs can be increased by the inclusion of conductive fillers into the insulating resin matrix. The structures of the Ag/Cu powders and ECAs were characterized by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS), respectively. The morphology investigation showed that the silver coatings were compact and continuous. It was found that the ECAs can be solidified through chemical sintering in air at 150 °C for 30min. The minimum volume resistivity was shown to reach2×10-4Ω•cm, suggesting excellent electrical conductivity, which makes us believe that the silver films have excellent oxidation resistance and could be broadly applied in the preparation of ECAs.