Soft error rates in solder bumped packaging

Many of the heavier elements used in chip packaging undergo radioactive decay and emit energetic alpha particles. Although the rate of emission is extremely low in terms of health concerns, over the operational life of a circuit the probability of a radiation-induced soft error can be substantial. In this paper I review the physical basis of alpha particle emission and present measurements of the alpha particle emission from materials used in MCNC's solder bumping process, including PbSn solder and BCB.