Kulicke and Soffa Investments, Inc.

Michael J Sheaffer

Lee R Levine

William J Holdgrafer

The present invention method is carried out with a programmable automatic wire bonder having a linear drive motor. The wire bonder is programmed to bond loose lead frame leads at a second bond position in a novel manner. The lead frame lead to be bonded at second bond is clamped in a work holder that leaves the ends of the lead frame leads loose above the bonding mandrel of the work holder but restrained to a predetermined floating zone that is established within a predetermined distance above the bonding mandrel. The bondig tool is programmed to engage the loose lead frame lead at second bond at a predetermined velocity which permits the bonding tool to simultaneously exert an impact force on the wire to be bonded and to clamp the loose lead frame lead. While the bonding tool is applying the impact force and simultaneously clamping the loose lead frame lead a second relatively high bonding force is applied to the bonding tool to complete a second bond without incurring bounce, or transient vibrations while making the second bond.

High yield clampless wire bonding method

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.

Growing community of inventors

Newtown, PA, United States of America

Michael J Sheaffer