| abstract |
The present invention provides a structure for joining the ball joints of a multilayer copper bonding wire, the structure having inexpensive material cost, low looping, superior ball joining properties, and high suitability for the mass production of multilayer chip connections. The structure for joining a ball joint (3) is formed by joining a ball portion formed on the tip of a multilayer copper bonding wire, the bonding wire having a core (21) that contains copper as a principal component thereof, and an outer layer (22) formed on the core, the outer layer containing at least one precious metal selected from Pd, Au, Ag, and Pt as a principal component thereof. A first concentrated section (10) of the precious metal is formed in a ball base area (9) positioned at the boundary with the copper bonding wire, the area being located in the surface region of the ball joint. |