OSP TREATED Cu BALL, SOLDER JOINT, FOAM SOLDER, AND SOLDER PASTE

摘要

The present invention assures alignment properties when mounting a Cu ball on an electrode while suppressing occurrences of soft errors. An OSP treated Cu ball (11) is provided with a Cu ball (1) and an organic coating (2), containing an imidazole compound, that covers the surface of this Cu ball (1). The Cu ball (1) is such that the purity is 99.9 - 99.995%, the U content is 5 ppb or less, the Th content is 5 ppb or less, the Pb or Bi content or the total amount for the content for both Pb and Bi together is 1 ppm or greater, the sphericity is 0.95 or greater, and the alpha dose is 0.0200 cph/cm2 or less.