BONDING WIRE

PURPOSE:To make it possible to use copper wire in place of a gold wire, by forming the wire by using a copper base material including zinc. CONSTITUTION:Wire is formed by using a copper base material including zinc within a range of 10-500ppm. The zinc 6 in the wire 5 is preferentially bonded with atmospheric oxygen 2, and selective oxidation is performed. The oxidation of the copper, which is the base material of the wire 5, is suppressed, and the diameter of the wire is not reduced. Thus, the strength of the wire 5 is secured, and the increase in electric resistance is prevented. When the amount of inclusion of the zinc 6 is 10ppm or more, a practical effect by the selective oxidation is obtained. When the zinc 6 is included in the copper base material, it is considered that the hardness of a ball 10 at the tip part of the wire 5 becomes high and the bonding property of the wire 5 and an aluminum electrode 12 is extremely hampered. When the amount of inclusion of the zinc 6 is 500ppm or less, however, the zinc 6a is evaporated and removed when the ball 10 is formed. The ball 10, which is used for the bonding, is made to be the pure copper. The softness is restored without impairing the bonding property. Thus the ball bonding property is assured.