Formation of Sn-rich phases via the decomposition of Cu6Sn5 compounds during current stressing

Abstract

This study examined the formation of Sn-rich phases in the matrix of Cu-Sn-Ni intermetallic compounds (IMCs) after current stressing of 1.2 X 104 A/cm(2) at 160 degrees C. The Sn-rich phases were formed at the cathode end of the solder joints with Cu metallization, and this formation was attributed to the decomposition of Cu6Sn5 IMCs. When the Cu6Sn5 IMCs were transformed into Cu3Sn during current stressing, Sn atoms were released. When the supply of Cu atoms became deficient, Sn atoms accumulated to form Sn-rich phases among the Cu-Sn-Ni IMCs. (C) 2014 Elsevier B.V. All rights reserved.