PURPOSE: To prevent the decrease of mechanical strength of a ball of a gold wire for bonding, by surrounding the outer periphery of a capillary with a cooling element, surrounding and forming a ball forming space having a bottom with a diaphragm, on a torch electrode and the outer periphery of a gold wire just above the torch electrode.
CONSTITUTION: In a ball forming equipment A equiped with crystal growth restraining element of gold wire for bonding, a cooling element 2 is arranged on the outer periphery of a capillary 1. Said cooling element 2 cools the capillary 1 and a gold wire S drawn out from the capillary through the capillary toward just above a torch electrode 3, and prevents the temperature rise of the gold wire S at the time of wiring. On the outer peripheries of a torch electrode 3 positioned just under the capillary 1 and of the gold wire S drawn out just above the torch electrode, a ball forming space (a) having a bottom serving as a cooling space (b) is surrounded with a diaphragm 4 and formed. A lot of jetting outlets 5....are opened in the diaphragm 4 toward the ball forming space (a). Cooling air supplied through vent holes 6 is jetted in the space from each of the jetting outlets 5 on the periphery.
AKIMOTO HIDEYUKI
YAMAMOTO TAIYO
