both cu electrodes and ni electrodes is preferably used for bump formation on packaged parts such as bgas and csps having electrodes on their bottom surfaces if the ag content of an sn u2014 ag u2014 cu u2014 ni based solder alloy for a solder ball according to the present invention is less than 0 5 mass the strength of the solder decreases and fracture of the solder occurs easily when undergoing an impact stress due to dropping or the like if the ag content exceeds 1 1 mass the hardness of the solder becomes high and its impact absorbing properties decrease thereby causing peeling to take place at the interfaces accordingly the ag content of an alloy for a solder ball according to the present invention must be 0 5 1 1 mass and more preferably 0 9 1 1 mass if the cu content of an sn u2014 ag u2014 cu u2014 ni based solder alloy for a solder ball according to the present invention is less than 0 7 mass the alloy composition moves away from the eutectic point of sn u2014 ag u2014 cu as a result when using cu electrodes due to diffusion of cu from the cu electrodes into solder a thick cu 6 sn 5 intermetallic compound layer is formed in the interfaces of the cu electrodes thereby decreasing the resistance to drop impacts of the solder if the cu content of an sn u2014 ag u2014 cu u2014 ni based solder alloy exceeds 0 8 mass the alloy composition moves away from the eutectic point of sn u2014 ag u2014 cu so cu 6 sn 5 intermetallic compounds easily form in.