Measurement of Alpha Particle Radioactivtiy in IC Device Packages

Alpha particle radioactivity in package materials has been shown to cause soft errors in semiconductor devices. The particles are emitted by uranium and thorium decay sequence radioactive isotopes present as trace impurities in the raw materials used to make the package component parts. Chemical and radiation analys s techniques were correlated to alpha particle fluxes, which range in value from 10 to 100 α/cm2-hr. for hermetic seal glasses, through 0.1 to 1 α/cm2-hr. for alumina, to less than 0.1 α/cm2-hr. for silicon, gold plating, and metal lids. Details of measurment techniques as well as specific package component radioactivity data are presented.