In the protection of the earth environment, the substitution of the solder material that does not contain lead (Pb) is advanced. Sn-3Ag-0.5Cu is frequently adopted as a de facto standard composition the solder paste material for the mounting. Sn-3Ag-0.5Cu solder which are the same to mounting solder composition are mass-produced about the solder ball used to package BGA. However, Sn-Ag solder have a big problem in thermal damage for heatproof parts because of being about 40°C higher than past eutectic solder. To solve this problem, we should consider the low reflow process. As for Sn-Zn solder, the expectation is also great as present equipment can be used, and practical use is begun. And we should consider with the low temperature process for low-cost and reliability in the semiconductor package assembly. We paid attention to the Sn-Zn solder material for solder ball material used to package BGA, and report on the influence in the solder joint reliability and the process of the packaging.
