Ultrasonic-assisted soldering of Sn/Ni composite solder during die bonding for high-temperature application

Abstract

The wide band-gap semiconductor devices, such as SiC, GaAs power devices, provide great opportunities to develop power electronic systems with increased power densities, high reliability in extreme environments and higher integration density. High-temperature resistance is needed for the thermal interface materials. In this work, the intermetallic joints consisted of nearly sole Ni3Sn4 during die bonding for high temperature applications were achieved with Sn-24 wt.%Ni by pressureless ultrasonic-assisted soldering in air for 10 s. This high re-melting temperature joint possessed high shear strength of 43.4 MPa and good microstructural stability as isothermally aged at 300 °C for 72 h in air. After aging, the IMCs phase did not change and the shear strength dropped (33.4 MPa) due to the Ni3Sn4 grains coarsening. These results demonstrate that the less time-consuming ultrasonic-assisted soldering has shown its potential for high temperature power electronic packaging.