Electromigration Reliability of Au Wire Bonding after Molding

Electromigration (EM) reliability of Au wire bonding after molding was investigated. During EM tests the resistance curve of bonding wire can be divided into four stages, which are named as resistance fluctuation stage, stable stage, rapid increase of resistance stage and sample failure stage. The change of temperature had the same trend as that of resistance. Furthermore, lifetime declined with increased current, and two failure modes were found after EM test. One was wire break at anode or cathode, while the other was a failure at the first bonds mostly with crack between IMCs and Al pad.