| 摘要 |
PURPOSE:To facilitate satisfactory bonding on an unplated external lead by a method wherein a current is made to flow through a capillary and the external lead for preheating and then the current is cut off and an ultrasonic oscillation is applied. CONSTITUTION:A wire ball is formed at the tip of a wire 2 inserted through an electrically-conductive capillary 1 and pressed against a pad on a semiconductor pellet 3 to bond one end of the wire with an electric circuit 6 being turned off. The capillary 1 is moved and the wire 2 is pressed against an external lead 4 (unplated) by the capillary 1 and, by turning the electric circuit 6 on, a current (b) is applied to the capillary 1 the wire 2 the external lead 4 an electrode 5 serving also as a heating block to heat the contact part between the wire 2 and the external lead 4. After the preheating, the current application circuit 6 is turned off and an ultrasonic oscillation (a) is applied to complete the bonding. By employing the two-step bonding process, thermal influence on the capillary is reduced. |
