Rapid silver sinter joining technology for large area chips

A rapid, large-area, chip-level bonding technology is introduced, achieved by sinter bonding of porous silver preforms as the die-attach material providing reliable interconnects to meet the growing demand for heat dissipation and packaging efficiency of wide bandgap (WBG) semiconductors. A combination of material properties such as mechanical properties, high thermal conductivity, high temperature resistance and chemical stability of die-attach materials formed by silver sintering technology and a rapid large area sintering process. The interconnection of SiC dummy chips on silver-plated copper substrates was achieved by using the prepared preformed silver solder sheets, combined with an optimized process at a sintering temperature of 300°C, a soldering pressure of 10MPa, and soldering times of 1min, 3min, and 5min, respectively. The room temperature shear strength of the joints under each reflow time exceeded 40 MPa, and in particular, when the welding time was 5 min, the shear strength could reach 942.09 MPa. This silver preformed solder sheet makes it possible to interconnect SiC chips and metal substrates in short time and low temperature conditions, providing high efficiency and reliability for a wide range of applications in high temperature and high frequency electronics.