THE INTERACTIONS BETWEEN IN-SN SOLDERS AND AN ELECTROLESS NI-P DEPOSIT UPON HEAT-TREATMENT

The interactions between In-Sn solders and an electroless Ni-P deposit with in the multilayer combinations comprised of In-Sn/electroless Ni -P/Al were investigated with the aid of heat treatments at various tem peratures and durations. The main reaction product was identified with X-ray diffractometry (XRD) as In3Ni2 regardless of the In-contents of the In-Sn solders. The formation of this In3Ni2 compound occurred thr ough the diffusion of Ni towards the In-Sn solder. The intermetallic c ompound layer achieved its maximum thickness within 100 h upon heat tr eatment at 60 degrees C; the thickness of the compound layer did not i ncrease upon extending heat treatment. Sn tended to dissolve in the In 3Ni2 compound.