Preparation and characterization of Ag conductive adhesive with low resistivity

We used bisphenol-F epoxy resin as an insulating polymer matrix, micron silver flakes and silver nanoparticles as conductive fillers, and dimethylformamide (DMF) as an organic solvent to obtain a Ag conductive adhesive with low resistivity. The silver content, organic solvent, and the ratio of micron silver to nano-silver were thoroughly investigated and optimized. Ultimately, it was determined that the optimal formulation for the conductive adhesive consisted of 86 wt \(\%\) silver with 40:1 micron silver to nano-silver, 10.24 wt \(\%\) epoxy resin, and 3.76 wt \(\%\) DMF. Tests for resistivity and shear strength were conducted on the optimal formulation. A resistivity as low as 8 μΩ cm was obtained. The shear strength can reach to ~ 87 MPa. The reduction in resistivity of the conductive adhesive is attributed to the ability of the formulation to allow micron and nano-silver to be tightly linked in the conductive adhesive to form a good conductive network and promote electron tunneling effect. The current silver conductive adhesive shows promise in microelectronic packaging industries.