engleski

Clean galena, contaminated lead, and soft errors in memory chips

Lead (Pb) disks were exposed to a radon(Rn)rich atmosphere and surface alpha particle emission was detected over time. Cummulative 210Po alpha emission increased nearly linearly with time. Conversly, cummulative emission for each of218Po and 214Po was constant after one and two hours, respectively. Processing of radiation-free Pb ore (galena) in inert atmosphere was compared with processing in ambient air. Ambient air introduced Rn and its progeny (RAD) into the flux during processing so that the processed Pb contained Po isotopes. A typical coke used in lead smelting emitted numerous alpha particles. We postulated that alpha particles from tin/lead solder bumps, a cause of computer chip memory soft errors, may originate from Rn and RAD in the ambient air and/or coke used as a reducing agent in the standard galena smelting procedure.

Computer chip memory; soft errors; tin-solder bumps; no-alpha galena; alpha lead; no-alpha lead; radon progeny

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