Size Effect Between Micron-Silver Joint and Nano-Silver Joint in Die-Attached Interconnection

To achieve the electronic packaging requirements of different chips, the mechanical properties of silver paste as a packaging material were confronted with the threat of size effect, which seriously affects the reliability design of electronic packaging. Therefore, a comparative experimental and theoretical study was conducted on the size effect of the sintered joints formed by silver particles of different scales. Experimentally, silver micron particles and silver nanoparticles were used to prepare sintered joint specimens, and the overlap areas of the specimens are 4, 16, 36, 64, and 100 mm2, respectively. The size effect phenomenon that the shear strength of sintered silver joints decreases with the increasing overlap area was verified through experiments, and the mechanism of the size effect was explained based on the microstructure characteristics of sintered silver joints. Theoretically, statistical methods were used to determine the mean shear strength in this work, which can reduce the influence of shear strength variability caused by pores on experimental results, and a theoretical model was established based on the Gurson model to expound the reason for the size effect of sintered joints, which matched well with experimental data.