Solvent effect on pressureless and low-temperature sintering of Ag paste for die-attachment in high-power devices

Sinter joining technology based on Ag paste is becoming an attractive alternative of traditional Sn-based solder for high-temperature and high-reliability power electronics packaging due to the excellent high-temperature stability and thermal conductivity. However, the further application of this technology is restricted to the pressured and high-temperature sintering process of Ag paste. In this study, we achieved a pressureless and low-temperature sintering of Ag paste by the solvent modification. The hybrid Ag micron particles with an ether-type solvent can be sintered to a robust joint above 30 MPa at 180°C without the assistance of pressure. It was found that the interfacial bonding between paste and die has a close relationship with the evaporation of solvent and viscosity of paste by changing the arrangement of Ag particles in paste.