Communication-Formation of Porous Cu3Sn by High-Temperature Current Stressing

Abstract

Cu3Sn is a compound commonly formed in solder joints on Cu. In this study, two different Cu3Sn structures were observed at different stages of current stressing. A normal layer-type and pore-less Cu3Sn structure was obtained at the current density of 2.27 x 10(4) A/cm(2) at 222 degrees C after 12 h. However, a porous Cu3Sn structure was formed under the same current stressing conditions after 22 h. The formation of porous Cu3Sn is explained by the mechanisms of phase transformation and reaction. The porous Cu3Sn structure is frequently observed in Cu/solder/Cu microbumps with a reduced solder height after electromigration tests. (C) 2016 The Electrochemical Society. All rights reserved.