Effect of Ni-coated carbon nanotubes on interfacial intermetallic layer growth

In the present study, Ni-coated carbon nanotubes (Ni-CNTs) were incorporated into the Sn-Ag-Cu matrix, to form a composite solder. The interfacial intermetallic compound layer thickness formed on electroless nickel immersion gold (ENIG) metallized Cu substrate was determined under the as-soldered condition. It was observed that the addition of 0.01 wt.% Ni-CNTs into the Sn-Ag-Cu solder matrix, affected the formation of intermetallic compounds during the soldering reaction. For the reaction between the composite solder and the ENIG/Cu substrate, (Cu
_1-x
Ni
_x
)
₆
Sn
₅
and (Cu
_1-y
Ni
_y
)
₃
Sn
₄
were formed. The test results revealed that the thickness of interfacial IMC decreased from 2.30 ¿m to 1.84 ¿m with the addition of Ni-CNTs. Shear tests were also conducted on the as-soldered solder joints. The shear test results revealed that the composite solder joint exhibited a ~15% increase in yield strength and a ~17% increase in ultimate shear strength, as compared to its monolithic counterpart.