Thermal Reliability Study of Si-based Chip Nanosilver Sintered Interconnects

In this study, nano-silver was used for the pressureless sintered interconnection of Si-based chips with bare Cu frameworks. The effects of high-temperature aging for 500 h (175°C) and temperature cycling (-65°C to 150°C with a temperature change rate of 10°C/min) on the microstructure, interconnect delamination and mechanical properties of the nano-silver sintered interconnect joints were investigated under 500 tests. The results show that after high temperature aging inter-element diffusion intensifies, the transition from dense to sparse nanosilver solder joints and the change of porosity occur, and their highly reliable interconnections are realized while forming Cu-Ag eutectic; after the temperature cycling test, the nanosilver sintered layer tends to be more dense, the voids are fine but more dispersed, and cracks tend to sprout at the bond boundary surface due to the mismatch of thermal expansion coefficients; after the thermal reliability test from, the mechanical properties showed that the nano-silver sintered joints are more suitable for long time high temperature environment and long-term use under rapid temperature change than the traditional high lead solder joints (maximum 33.1MPa at 180h and 25.6MPa at 500h).