Patent ID: 7145236

Claim:
A semiconductor device having solder bumps each adapted to be connected to a Pb-free solder paste provided on each of pads of a substrate on which the semiconductor device is to be mounted, the Pb-free solder paste consisting, by mass, of from about 2.0% to about 3.5% silver, about 0.3% to about 0.8% copper, and the balance of tin, each of the solder bumps being Sn—Ag—Cu alloy Pb-free solder and having a solder composition of the same kind as that of the Pb-free solder paste, wherein a content of silver contained in the solder bumps is lower than that of silver contained in the Pb-free paste, and wherein a melting temperature of the solder bumps is higher than a melting temperature of the Pb-free solder paste.