| 摘要 |
PURPOSE:To make it possible to perform direct wire bonding to a leadframe, whose silver plating and the like are omitted, by applying ultrasonic wave vibration to a pusher, which has a smooth surface at the tip part, pushing the leadframe, and forming a transferred smooth surface. CONSTITUTION:Ultrasonic wave vibration in the lateral direction or in the longitudinal direction is applied to a pusher 12. Under this state the pusher 12 is made to push the surface of a leadframe 10, which includes a part 12a to be stitch-bonded. Then the pushing of the pusher 12 is stopped and it is moved upward. The pushing conditions of the pusher 12 are set as follows: e.g., the amplitude of the ultrasonic vibration is 25-60mum; and the applying pressure P of the pusher 12 is 0.2-2kg/mm<2>. The deformation resistance of a leadframe raw material 10 is suppressed. Very fine irregularities on the surface of the raw material 10 are eliminated. A part to be bonded is smoothed so that its surface roughness becomes 0.3mum or less in R2 conversion. The part to be bonded is softened by the action of the ultrasonic vibration. Thus a transferred smooth surface 11a is formed. |
