Alpha emission of fully processed silicon wafers

Measured alpha particle emissions from packaging materials have been used to calculate the Soft Error Rate of silicon components. The packaging materials have been assumed to be the only alpha emitter and the layers on top of the silicon have been assumed to be the alpha attenuators. This paper measures the alpha emission of the fully processed wafers from different vendors and shows that these wafers are significant alpha emitters. Because the alpha emitters in this case are very close to the silicon, there are no shielding layers to attenuate the lower energy alpha particle. The entire alpha particle energy spectrum, from both package materials to the inside wafers, must be considered, when calculating the alpha flux at the silicon die.