| 摘要 |
Provided is a core ball with a low α dose, capable of suppressing a soft error, and being made at a joint fusion temperature, which is not problematic to packaging. Metal power, which becomes a core, has a globe shape, and if a Cu ball is used for the metal power, the purity is from 99.9% to 99.995%. The content of Pb or Bi, or the content of the sum of Pb and Bi is not less than 1ppm, and the sphericity of the Cu ball is not less than 0.95. A solder plating film, coated on the Cu ball, is an Sn-Bi alloy. U, included in the solder plating film, is not more than 5ppb, and Th is not more than 5ppb. A α dose of the core ball is not more than 0.0200cph/cm^2. |
