| 摘要 |
PURPOSE:To prevent the neck breakage, due to heat cycle, of the titled wire to be obtained and also to facilitate thermocompression bonding and ultrasonic compression bonding to outer lead, by coating a copper-alloy core wire containing specific amounts of Cd with high-purity copper. CONSTITUTION:A copper alloy in which 50-500ppm Cd 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 a bonding wire A of desired diameter is formed. In this way, tip crack can be prevented when balls are formed by melting a tip at the time of bonding, and neck breakage due to heat cycle can also be prevented. |
