WIRE BONDING

PURPOSE:To prevent an insulating oxide film from cracking by reducing the output of an ultrasonic wave to be applied to a ball while the ball formed at the end of a bonding wire is brought into pressure contact with a pad. CONSTITUTION:A ball 31 formed at the end of a bonding wire 30 by a torch is brought into pressure contact with a pad 11 by a capillary 40. That is, the ball 31 is brought into pressure contact with the pad 11 at a time T1, and an ultrasonic wave is applied to the ball 31 at a time T2. While the ball 31 is brought into pressure contact with the pad 11, the output of the wave is reduced. When the output is gradually reduced, the wave starts applying at the time T2, the output is gradually reduced simultaneously upon arriving at the maximum output B, and when it becomes an output A at a time T4, the oscillation of the wave is simultaneously stopped. Thus, it can prevent an insulating oxide film from damaging such as cracking.