| 摘要 |
<p>A method of forming a ball on a wire by spark discharge to permit ball bonding of the wire to a component or a terminal comprises: initiating the formation of an arc between an electrode and the wire by applying between them a high voltage (V2) from a high-voltage, low-current source (46, 64 to 76) which is effective only until the arc is formed; and, once the arc has been formed, drawing current for forming the ball from a low-voltage (V1), high-current source (44, 50-56). Apparatus for forming a ball on a wire by this method can be completely safe, by using a very low capacitance (76) in the high voltage source, which is made to discharge through a resistor (74). Sufficient power for forming the ball can be provided by the low-voltage source provided that it incorporates a very large capacitance (52). The method can alternatively be performed with the use of electronic power supplies, supplied for example by constant-current sources.</p> |
