| 摘要 |
PURPOSE:To prevent the damage to the surface part of a semiconductor chip and to improve the stability of looping by incorporating, as the alloy component, specific ratio of B into the titled wire and regulating the content of S as the impurities to the specific value or below, thereby decreasing the hardness and work hardening of the wire. CONSTITUTION:The copper alloy for the extra fine wire contg. 1-100ppm B, contg. at need one or more kinds among 1-10ppm rare earth elements of Be, Ca and Ge and consisting of the balance Cu with inevitable impurities (where the content of S as the impurities is regulated to <=0.5ppm) is prepd. The work hardening accompanied by the deformation of the ball part formed on the tip part of each wire is remarkably suppressed and the hardness of the ball part is as well lowered by the decrease of S content and the addition of B in this manner. The semiconductor chip and the coat on the surface are therefore hardly subjected to damage and the generation of an edge shot to the semiconductor chip is remarkably suppressed by the stabilization of the looping. The looping is furthermore stabilized by the addition of the rare earth elements, Be, etc., to the alloy. |
