| 摘要 |
PURPOSE:To form a ball so as not to have the center of the ball eccentric to a capillary. CONSTITUTION:A protrusion 3b made of highly conducting material is provided on the upper plane of a torch electrode 3' and, further, a transfer mechanism 8 which positions the tip of the protrusion directly below the wire guide hole 9 of a capillary 2 which holds a bonding wire 1 is provided. As the protrusion 3b is provided on the discharge plane of the torch electrode 3' and the discharge position is always the tip of the protrusion 3b, if the bonding wire 1 protruding from the tip of the capillary 2 is bent so much as to be the cause of producing a club ball, the distance between the tip of the bonding wire 1 and the discharge position becomes large and the discharge is not induced or the discharge current is reduced (or a voltage is elevated). By monitoring the status of the current, the defective ball formation is detected and the bonding operation is discontinued, so that the formation of the club ball can be avoided. |
