Experimental Investigation on the Sintering Kinetics of Nanosilver Particles Used in High-Power Electronic Packaging

Abstract

Better mechanical, thermal properties and longer lifetimes are needed for the die attach layer in high-power electronic packaging. As traditional Sn-Ag-Cu (SAC) solders have many limitations, the sintered nanosilver materials are becoming one of the substitutes for high-power electronic packaging. However, the high performance of sintered nanosilver materials is only achieved when its fine sintering densification is formed. This article investigates the sintering densification process of nanosilver particles based on the design of orthogonal experiments and sintering kinetics modeling in which both the macroproperties and micromorphology are linked and analyzed. The results lead to several conclusions, such as: 1) the orthogonal experiments consider the effects of sintering temperature, dwell time, and sample preparation pressure on the sintering relative shrinkage and relative density - the results show that the most critical impact factor on sintering densification is the sintering temperature. (2) In the sintering kinetic experiments, the sintering densification rates obtained by fitting the relative density versus dwell time curves during 175 °C-250 °C follow the Arrhenius model, and the apparent activation energy of sintering kinetics is calculated to be 36 kJ/mol, while it is calculated from the particle size is 38.1 kJ/mol. 3) Through modeling the relationship between particle size, line shrinkage, and porosity, the line shrinkage and porosity first increase at the initial stage, while the particle size increases, and the macroscopic volume decreases at the end of sintering, the porosity decreases.