Investigation on the Morphology of Sintered Silver Nanomaterial for Electronic Packaging Application

Silver nanoparticles are seen as a possible replacement for high temperature solders containing 90-95 wt.% Pb, which is widely used in various applications e.g. automotives. These high temperature solders have been exempted from the Restriction of Hazardous Substances (RoHS) Directive due to very limited drop-in replacement for the high temperature solders. Although the effect of sintering temperature of silver nanoparticles has been studied, the mechanism involved in the changes in the morphology of the particles and interfacial reaction with the substrate as a function of sintering temperature must be understood. In this study the effect of sintering temperature on the morpohology of Ag nanoparticles is discussed. The Scanning Electron Microscopy (SEM) analysis was used to analyze the changes in morphology of silver particles agglomerates with sintering temperatures. Results showed necking of the nanosilver powder, which indicated the occurrence of sintering through grain boundary diffusion process. Meanwhile, the micro-silver powder showed agglomeration of particles but no necking was observed. The study has shown that the Ag agglomerates was observed to undergo various changes to the particle morphology with different sintering temperatures.