Core ball, solder paste, formed-solder, flux-coated core ball and solder joint

摘要

A core ball wherein a junction melting temperature and a low alpha dose are set for suppressing a soft error generation and solving a mounting problem. A metallic powder as a core is a sphere. A pure degree of a Cu ball of the metallic powder is equal to or higher than 99.9% but equal to or less than 99.995%. A contained amount of one of Pb and Bi or a total contained amount of Pb and Bi is equal to or higher than 1 ppm. A sphericity of the Cu ball is at least 0.95. A solder plating film for coating the Cu ball comprises Sn—Bi based alloy. U contained in the solder plating film is equal to or less than 5 ppb and Th is equal to or less than 5 ppb. An alpha dose of the core ball is equal to or less than 0.0200 cph/cm2.

主权项

1. A core ball, comprising:
a sphere-shaped metallic powder forming a core; and a solder plating film coating the surface of said metallic powder; wherein said metallic powder is a sphere in which a metallic degree of purity is equal to or higher than 99.9% but equal to or less than 99.995%, a total contained amount of Pb and/or Bi is equal to or larger than 1 ppm and its sphericity is equal to or higher than 0.95; said solder plating film is a Sn—Bi based Pb-free solder alloy including Bi in an amount of 40-60 mass percent and in which a contained amount of U and Th is equal to or less than 5 ppb respectively; and the alpha dose of said core ball is equal to or less than 0.0200 cph/cm2.