Apparatus for supplying uniform tail lengths

The method of making uniform tail lengths under a bonding tool after a last bond comprising the steps of:

• bonding a fine bonding wire to a semiconductor device target with a bonding tool,
• clamping said bonding wire with wire clamps,
• moving said wire clamps in a direction to break said fine bonding wire at said bonding tool,
• measuring the differentially displacement of said wire clamps during the differentially elongation of said fine bonding wire between said bonding tool and said wire clamps until said bonding wire breaks at said bonding tool, and
• differentially moving said wire clamp in a direction to supply a predetermined tail length of wire under the working face of said bonding tool without the elongation of said fine bonding wire to provide a uniform tail length under said bonding tool.

Apparatus for supplying a uniform length tail bonding wire to a bonding tool of an automatic wedge bonder of the type having articulating wire clamps comprising:

• a transducer mounted on said wedge bonder,
• a bonding wedge mounted in said transducer opposite a semiconductor device to be bonded,
• wire clamp means mounted on said wedge bonder for clamping a bonding wire fed to said bonding wedge,
• means for moving said wire clamp means for elongation and breaking said bonding wire at a last bond and for feeding a predetermined length tail minus the amount of elongation under the working face of said wedge bonding tool,
• timing means coupled to said means for moving said wire clamp for measuring the differential elongation imparted to said bonding wire before said bonding wire breaks,
• circuit sensing means coupled to said transducer and to said wire clamp means for sensing the absence or presence of said bonding wire under said bonding wedge,
• wire feed drive motor means for supplying a slack loop of bonding wire to said bonding wedge, and
• control means coupled to said circuit sensing means, said timing means and said wire feed drive motor means for detecting the absence of a bonding wire at said bonding wedge and the amount of elongation of said fine wire and movement of said wire feed drive motor means.