Phase identification and interface evolution of ENIG/Cu-core SAC305/ ENIG solder joints after the thermal-electrical coupling reliability test

摘要

Cu-core solder joints are promising interconnections for 3D IC. The joints are able to possess a long life-time under thermal-electrical coupling reliability tests. Apart from that, the microstructure inside the tested joints is truly fascinating. Due to the core structure in the joint, there are two short paths for electrons and atoms to migrate during electromigration tests. Besides, complicated phase evolution was revealed at the interfaces in the joint. In this study, Cu-core solder joints underwent a 750-hour thermal-electrical test. Subsequently, elemental analyses were carried out to probe the phase distribution and to interpret the evolution at the interfaces in tested joints. (C) 2020 Elsevier B.V. All rights reserved.