Lead-free solder, lead-free solder ball, solder joint using the lead-free solder and semiconductor circuit having the solder joint

摘要

Lead-free solder is characterized in that the lead-free solder contains Ag of 1.2 mass % through 4.5 mass %, Cu of 0.25 mass % through 0.75 mass %, Bi of 1 mass % through 5.8 mass %, Ni of 0.01 mass % through 0.15 mass % and Sn as the remainder. These addition amounts allow to be further improved the common solder properties such as wettability, shear strength properties and the like, in addition to the thermal fatigue resistance.