Patent ID: 8836147

Claim:
A bonding structure of a ball-bonded portion obtained by bonding to a bonding-target portion a ball portion formed on a front end of a multilayer copper bonding wire, wherein said multilayer copper bonding wire comprises: a core member mainly composed of copper; and an outer layer formed on said core member and mainly composed of at least one noble metal selected from the group of Pd, Au, Ag and Pt, wherein said bonding structure comprises a first concentrated portion having a high total noble metal level and being formed in a ball-root region, said ball-root region being in such a surface region of said ball-bonded portion as is located at a boundary with said multilayer copper bonding wire, wherein said high total noble metal level accounts for all of said noble metals selected, and wherein a total concentration of said at least one noble metal selected in said first concentrated portion is not lower than 0.05 mol % and not higher than 6 mol %.