Porosity and Young's modulus of pressure-less sintered silver nanoparticles

For harsh service conditions, sintered silver nanoparticles (AgNP) own the most appealing advantage of low temperature sintering and high temperature service. More importantly, sintered AgNP has superior high thermal and electrical conductivities compared with conventional solder materials, which will greatly benefit its application to packaging structures with high current density in advanced electronic devices. However, the microstructural morphology under different sintering conditions and the determination of Young's modulus of sintered AgNP with such a porous microstructure is imperative to be investigated. In the present study, the sintering condition for AgNP are firstly compared by applying pressure-less condition with the sintering temperature of 200°C for 90 min in two feasible approaches in practice, that is, electric forced-air heating oven and sintering furnace. To illustrate the superiority of sintered AgNP, the thermal conductivity is measured based on laser flash method and compared with conventional Sn-37Pb, Sn-3.0Ag-0.5Cu and silver electronic conductive adhesive. The formed microstructures based on both sintering conditions for different soldering structures are discussed in terms of porosity. Lastly, the Young's modulus of AgNP samples with a porous microstructure is determined using nanoindentation at different applied strain rates.