Diversifying grain orientation and expediting 10 μm Cu/ Sn/Cu TLP bonding process with Ni doping

摘要

Prolonged bonding time and the excess thermal stress have been the bottleneck for transient liquid-phase (TLP) bonding in heterogeneous integration. To alleviate such issues, adequate amount of Ni was added to the Sn-3.0Ag-0.5Cu (SAC305) solder. With addition of Ni, the time elapsed for complete TLP bonding was shortened significantly. The distinct correlation between inter-metallic compounds (IMCs) morphology and Ni content was investigated on both top and bottom substrates. Moreover, the effect of Ni on diversification of grain orientation of IMCs was also quantified by electron backscatter diffraction (EBSD). Also, Ni doping in TLP bonding provided smaller grain sizes. The mechanical strength of the TLP interconnection is therefore expected to be enhanced by Ni doping in solder.