| 摘要 |
PURPOSE:To form constant the diameter of a ball and to improve the accuracy of a bonding by a method wherein the length of a covering gold wire is detected to find a current value at which the diameter of the ball can be constant, which is formed at the tip of the gold wire, and a current which is made to flow through the gold wire is controlled. CONSTITUTION:A covered gold wire 2 which is fed from a wire-feeding means 1 is inserted in a capillary 4 via a clamper 3, the terminal 5 of the gold wire is connected to the side of a cathode of a power supply and an electric torch 6 is connected to the side of an anode of the power supply. A covered gold wire length detecting means 7 detects the length between the tip and the terminal 5 of the wire 2 and a current arithmetic means 8 calculates a resistance from the detected length and calculates a current value, at which the diameter of a ball 2a to be formed by discharge between the tip of the wire 2 and the torch 6 is made constant. Then, a current control means 9 controls a current, which is made to flow through the wire 2, on the basis of the operated value sent from the means 8. Thereby, the diameter of the ball which is formed at the tip of the wire 2 is made constant and a high-accuracy bonding can be conducted. |
