Lead-free solder connection structure and solder ball

摘要: Solder used for flip chip bonding inside a semiconductor package was Sn—Pb solder such as Pb-5Sn composition. Lead-free solders which have been studied are hard and easily form intermetallic compounds with Sn, so they were not suitable connection structure package, requires stress relaxation properties. This problem is eliminated by using lead-free characterized consisting essentially of 0.01-0.5 mass percent Ni remainder Sn. 0.3-0.9 Cu 0.001-0.01 P may be added to this