SiC chip attachment sintered by nanosilver paste and their shear strength evaluation

In this study, a nanosilver paste was prepared by silver nanoparticles and organics, by which an SiC ship could be sintered on the direct bonding copper (DBC) substrate at 250–300 °C. The nanosilver paste firmly sintered the SiC chip and DBC substrate, and die attachment had an excellent bonding interface. Die-shear results showed that the shear strength increased with the increase of sintering temperature and was more than the value required by the MIL-STD-883J standard. When high assisted pressure was applied, the sintering temperature could be lowered and sintering time also could be shortened to realize attaching high bonding strength. The assisted pressure also influenced the porosity of the bondline. X-ray non-destructive method was used to measure the porosity of die attachment. The results showed that the shear strength of die attachment decreased with the increase of bondline porosity.