BALL BONDING WIRE

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Disclosed is a bonding wire (W), which has high bondability to an Ni/Pd/Au coated electrode (a) having high reliability at high temperatures, causes less damage to brittle chips, and has low cost. Specifically disclosed is a silver bonding wire for connecting to each other the Ni/Pd/Au coated electrode (a) of a semiconductor element and conductor wiring (c) of a circuit wiring board by means of a ball bonding method, said silver bonding wire having a wire diameter of 10-50 μm. A coating layer (2) composed of Pt or Pd is formed on the outer circumferential surface of a core material (1), and the ratio (%) between the cross-sectional area of the coating layer and the cross-sectional area of the wire is set at 0.1-0.6 %. Since a spherical FAB (ball (b)) shown in Fig. (a, b), said FAB having no unmelted portion (hollow), can be obtained by having a coating layer thickness (t) with the cross-sectional area ratio, chip damages are not easily generated. The core material (1) contains, in total, 0.5-5.0 mass % of one or more kinds of elements selected from among Pd, Pt and Au, 5-500 mass ppm of one or more kinds of elements selected from among Ca, Cu and rare earthes, and the remainder composed of Ag and inevitable impurities.