Bonding wire ball forming method and apparatus.

摘要

Method and apparatus for forming a ball at the end of bonding wire or lead wire in a capillary wire holding and bonding tool is described suitable for ball bonding of copper and aluminum lead wire to integrated circuit chips. A ball is formed by substantially enclosing the end of the bonding wire in a shroud or shield, flooding the shroud or shield and the end of the bonding wire with an inert gas, and generating a controlled pulse train of a preset count of electrical pulses for establishing arc discharge between the wire and the shroud or shield. The method permits precise control and metering of energy delivered by controlling the parameters of the pulses of the pulse train for melting and forming a ball of uniform quality without oxidation of the metal. Corresponding apparatus and circuitry are described which may be retrofitted into stock ball bonding machines or provide new machines.