Thermo-Mechanical Characteristics and Reliability of Die-Attach Through Self-Propagating Exothermic Reaction Bonding

Self-propagating exothermic reactions (SPERs) provide intense localized heat sufficient for bonding metals or alloys with minimal heat excursion to the components, which shows great potential for the die-attach in power electronics packaging. However, the reliability of such formed joints is yet to be fully understood owing to a wide range of defects involved in the instantaneous propagating reaction and heating/cooling. In this work, the finite element analysis is performed to understand the thermal transfer and mechanical responses of materials to the SPER bonding for the die-attach of Si device onto direct bonded copper (DBC) substrate with Sn-3.0Ag-0.5Cu (SAC) solder. The simulation has been validated using the temperature distribution in SPER bonding, which shows a good agreement with the actual measured results. Moreover, a systematic investigation on the mechanical responses due to thermal mismatch reveals their effects on the thermal stress of interfaces and bonding reliability.