Effect of silver powders on a low curing temperature silver conductive adhesive

In this paper, some different types of epoxy electrical conductive adhesive (ECA) are prepared and investigated. Flake silver, spherical silver and the mixture of them are employed to fabricate ECA samples, respectively. With different percentage of filler loading, the morphology, adhesion, hardness, resistivity and differential scanning calorimeter (DSC) test of the silver filled ECA samples are compared and analyzed. By comparing the samples, it is found that the adhesion do not change a lot from each other. While in terms of hardness and resistivity, flake silver shows a better performance than spherical silver. The scanning electron microscopy figures of the ECA samples reveals that the mixed silvers have a better filler distribution and form a more dense conductive network than the single component—flake silver or spherical silver. Furthermore, when the ratio of flake silver to spherical silver reaches a suitable value, the ECA achieves the optimum electrical conductivity. Finally, the DSC test result shows the appropriate curing temperature for the ECAs.