Low-Temperature Sintering Mechanism and Bonding Performance of Submicron Triangular Silver Paste for Advanced Electronic Packaging

Silver pastes are promising joining materials for use in advanced electronic packaging, particularly in power electronics, due to their capacity for low-temperature joining and high-temperature operation. However, spherical silver particles suffer from low sintering efficiency and high porosity due to their limited contact areas. In this study, a submicron triangular silver flake paste was investigated to overcome these limitations. A high joint strength of 35.2 MPa with a low porosity of 9.48% was achieved at 250 °C via pressureless sintering. A relatively high thermal conductivity (134.9 W/(m·K)) was also achieved. This enhanced sintering performance is attributed to a unique mechanism involving distinct same-layer and inter-layer sintering processes at different temperatures. With these findings, we demonstrate that the submicron triangular silver flake paste is a high-strength, high-thermal-conductivity, low-temperature bonding material for advanced electronic packaging.