Reliability of composite solder bumps produced by an in-situ process

In an attempt to develop a thermally stable solder system, an in-situ Pb-Sn solder composite reinforced with Gu,Sn, dispersoids was investigated for i ts thermal stability. The stability was evaluated mainly by measuring the g rowth rate of intermetallics at in-situ composite solder/BLM interface as a function of the number of reflow soldering cycles and aging time. The rate s were compared with those of the eutectic Pb-Sn and Sn-Ag solders. After t he thermal treatments, the solder joints were tested for their shear streng ths. The results indicated that the in-situ composite solder has a higher s hear strength and better thermal stability than the eutectic Pb-Sn solder.