| 摘要 |
PURPOSE:To prevent the neck breakage of the titled wire to be obtained due to heat cycle and also to facilitate thermocompression bonding and ultrasonic compression bonding to outer lead, by coating a copper-alloy core wire containing specific amounts of Bi with high-purity copper. CONSTITUTION:A copper alloy in which 10-100ppm Bi as a recrystallization- improving element is incorporated to high-purity copper of >=99.99wt% purity is used as a core wire 1, on which a clad 2 composed of high-purity copper of >=99.99% purity is formed in a proper coating ratio. Subsequently, wire drawing and intermediate heat treatment are repeatedly applied to the above, so that bonding wire A of desired diameter is obtained. In this way, tip crack can be prevented when a tip is melted to form balls at the time of bonding, and also neck breakage due to heat cycle can be prevented. |
