Core material, semiconductor package, and forming method of bump electrode

A core material, comprising:

• a core;
• and
• an electric solder plating layer of an (Sn-58Bi)-based solder alloy made of Sn and Bi in an amount of a target content of 58 mass % on a surface of the core, wherein
• the core includes a metal simple substance of Cu, Ni, Ag, Bi, Pb, Al, Sn, Fe, Zn, In, Ge, Sb, Co, Mn, Au, Si, Pt, Cr, La, Mo, Nb, Pd, Ti, Zr, or Mg, or an alloy of two or more thereof, a metal oxide thereof, or a metal mixed oxide thereof, and
• when a concentration ratio of Bi contained in the solder plating layer is set to
• Concentration Ratio (%)=(Measured Value of Bi (mass %)/Target Bi Content (mass %))*100, or
• Concentration Ratio (%)=(Average Value of Measured Values of Bi (mass %)/Target Bi Content (mass %))*100,
• the concentration ratio is in a range of 91.4% to 108.6% across the entire electric solder plating layer.

A core material, comprising:

• a core;
• and
• an electric solder plating layer of an (Sn-40Bi)-based solder alloy made of Sn and Bi in an amount of a target content of 40 mass % on a surface of the core, wherein
• the core includes a metal simple substance of Cu, Ni, Ag, Bi, Pb, Al, Sn, Fe, Zn, In, Ge, Sb, Co, Mn, Au, Si, Pt, Cr, La, Mo, Nb, Pd, Ti, Zr, or Mg, or an alloy of two or more thereof, a metal oxide thereof, or a metal mixed oxide thereof, and
• when a concentration ratio of Bi contained in the solder plating layer is set to
• Concentration Ratio (%)=(Measured Value of Bi (mass %)/Target Bi Content (mass %))*100, or
• Concentration Ratio (%)=(Average Value of Measured Values of Bi (mass %)/Target Bi Content (mass %))*100,
• the concentration ratio is in a range of 90% to 107.5% across the entire electric solder plating layer.

A core material, comprising:

• a core;
• and
• an electric solder plating layer of an (Sn-3Bi)-based solder alloy formed of Sn and Bi in an amount of a target content of 3 mass % on a surface of the core, wherein
• the core includes a metal simple substance of Cu, Ni, Ag, Bi, Pb, Al, Sn, Fe, Zn, In, Ge, Sb, Co, Mn, Au, Si, Pt, Cr, La, Mo, Nb, Pd, Ti, Zr, or Mg, or an alloy of two or more thereof, a metal oxide thereof, or a metal mixed oxide thereof, and
• when a concentration ratio of Bi contained in the solder plating layer is set to
• Concentration Ratio (%)=(Measured Value of Bi (mass %)/Target Bi Content (mass %))*100, or
• Concentration Ratio (%)=(Average Value of Measured Values of Bi (mass %)/Target Bi Content (mass %))*100,
• the concentration ratio is in a range of 90% to 106.7% across the entire electric solder plating layer.