Defect formation and mitigation in Cu/Cu joints formed through transient liquid phase bonding with Cu-Sn nanocomposite interlayer

Joining based on transient liquid phase bonding (TLPB) has a great prospect in microelectronic packaging. However, this process is plagued with its low throughput. In work, we designed and utilised preformed Cu-Sn nanocomposite interlayer (Cu-Sn NI) to speed up the TLPB process. Comparing uses of Sn only, NI enabled be accelerated by >20 times. Furthermore, instead columnar Cu6Sn5 grains, intermetallic compounds joints formed NIs were mostly filled refined equiaxed grains an average size ~1.6 μm. As result, shear strength IMC achieved was found higher than those bonded interlayer. various kinds defects, one main drawbacks TLPB, still from unique process, which likely deteriorate performances long-term reliability resultant joints. This study aims observe analyse defects during NI, hence propose possible mitigation solutions prevent their occurrence consequently improve obtained NIs.