Method of making low profile fine wire interconnections

摘要

A novel method of making very low profile fine wire interconnections is accomplished with a conventional automatic gold wire ball bonder and includes the steps of making a conventional first ball bond and moving the bonding tool so as to pay out a length of wire that is shorter than the final desired length of wire to be used in the interconnection. The bonding tool is movingly engaged against the target on which the second bond is to be made employing a first bonding force which bends and conforms the wire beneath the working face of the capillary bonding tool and simultaneously forward extrudes and wire draws the neck of the fine wire into a tapered section which avoids backward extrusion. Subsequently a second bond force and ultrasonic energy is applied at the second bond target position to generate a conventional thermosonic second bond. The fine wire is bonded to the target by a thermocompression bond resulting from the moving first bonding force and the bond is interconnected to a conventional thermosonic bond resulting from the second bond force which produces a larger and stronger bond area than a conventional prior art second bond.