Adhesion Properties, Interfacial Evolution between OSP, Electroplated Nickel Gold, Electroless Nickel Gold (ENIG) Substrates and Sn-Ag-Cu-xCNT, Sn-Ag-Cu-x Nano particles (x= 0 to 1wt %) Solder Spheres

Keywords:
composite solders, intermetallic compounds (IMCs), ball shear strength, thermo-mechanical reliability

Abstract:
In the present report, effect of carbon nanotubes, nano-nickel, nano-molybdenum additions on the bonding strength and Interfacial morphology of the conventional Sn-Pb solders were investigated, when the composite solder spheres were bonded to the Cu/OSP, Electroplated Nickel Gold, Electro less Nickel Immersion Gold (ENIG) substrates.
The microstructure and the adhesion strength of the composite solder joints with the aforementioned substrates were examined by means of the ball shear testing. Compared to the Sn-3.8Ag-0.7Cu solder alloy joins, the composite solder joints exhibited better joint strength. Ball shear tests were conducted at higher speeds to evaluate the strength of the bonding
The special emphasis was focused on the Intermetallic Growth (IMC) during the solid state aging on OSP, Electroplated Nickel Gold, ENIG substrates. For the determination of the IMC growth kinetics the packages were subjected to thermal annealing at 125ºC, 150ºC, 175ºC for the different time periods. The growth kinetic mechanism is discussed in detail. X-ray diffraction techniques were employed to determine the IMCs and the phases presence in the solder matrix. FE-SEM was employed to determine the IMC thickness and EDX was utilized to analyze the composition of the IMCs.
Thermo-mechanical durability of the composite solders were evaluated by carrying the thermal cycle testing, in which the thermal cycling profile consisted of the temperature limits in the range of -55 to 125ºC.

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Nanotech 2006 Conference Program Abstract