High yield clampless wire bonding method

Abstract

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.

Dependencies are inferred from the claim text.