Microstructure, mechanical and electrical performances of zirconia nanopartieles-doped tin-silver-copper solder alloys

摘要

The present study investigates the influence of ZrO_2 nanoparticles addition on microstructure, material properties i.e., elastic moduli, creep behavior, hardness, shear strength and electrical resistivity of Sn-3.0Ag-0.5Cu (wt%)-based interconnected alloys. From microstructure observation it was revealed that in the plain Sn-Ag-Cu bulk solder a needle-shaped Ag_3Sn and irregular shaped Cu_6Sn_5 IMC particles were formed in the elongated-like β-Sn grains. However, in the composite solder alloy, very fine needle-shaped Ag_3Sn and irregular shaped Cu_6Sn_5 IMC particles were formed in equiaxed β-Sn grain matrix. Further, material properties like elastic moduli, hardness, creep behavior and electrical resistivity of Sn-Ag-Cu solder were improved significantly after adding the ZrO_2 nanoparticle. Sn-Ag-Cu-based composite solder joints were prepared on Au/Ni-metallized Cu pad ball grid array (BGA) substrate and investigated their performance after exposing a thermal shock chamber at -40 to 90 ℃. From this test, it was confirmed that the degradation behavior of plain solder joints was much faster as compared to the composite solder joints and also detected some micro-cracks at the interface and solder matrix. Further, the shear strength of plain solder joints was decreased significantly as compared to the composite solder joints.