In situ preparation and sintering of silver nanoparticles for low-cost and highly reliable conductive adhesive

A facile method to prepare low-cost, highly conductive and reliable silver-coated copper (Ag-coated Cu) flakes filled isotropic conductive adhesive (ICAs) by in situ generation and sintering of silver nanoparticles (AgNPs) during the curing process is presented. The silver–triethanolamine complex is derived from the complexing reaction between AgNO3 and triethanolamine in the epoxy matrix. At the curing temperature, AgNPs are in situ generated by the thermal decomposition of silver–triethanolamine complex. The sintering of AgNPs anchored on the surface of Ag-coated Cu flakes could effectively prevent the exposed Cu from oxidizing. Compared with the ICAs without AgNPs which has a resistivity of 9.6×10−4 Ω cm, the ICAs filled with AgNPs shows a much lower volume resistivity of 6.62×10−4 Ω cm. Furthermore, the contact resistance of the ICAs is only 6.7% increase after aging at 85 °C and 85% RH for 500 h, while the increase in contact resistance of the controlled ICAs reaches to 23%. The facile approach will pave the way towards high performance and low cost ICAs for electronic packaging applications.