Development of micron-sized Ag-Si composite paste die attach material for highly stable microstructure during high temperate aging

Ag paste sinter exhibits many advantages over other interconnect technologies, such as high electrical/thermal conductivities and wide operation temperature beyond 300 °C. However, sintered Ag paste tend to coarsen rapidly during aging at high temperatures, while the pore size and numbers decrease simultaneously with shape change at high temperatures due to Oswald ripening. Recent studies show that the micromechanical properties and fracture behaviour of sintered Ag paste largely depend on its microstructure, which relates not only on its porosity but also upon the degree of necking growth among the Ag particles. In this study, we developed a micron-sized cost-effective Ag-Si composite paste die attach material for highly stable microstructure during high temperate aging. A stable microstructure of sintered Ag-Si composite paste during high temperature aging for the reliability of structure by SEM and EBSD analysis. In addition, because of Si possessed some properties as low Coefficient of Thermal Expansion (CTE) value, the Ag-Si composite paste also is looking forward to reduce the CTE mismatch with SiC, thus improve the reliability during harsh thermal cycling.