Application of electroless Ni–Zn–P film for under-bump metallization on solder joint

A ternary Ni-8Zn-8P film was fabricated with alkaline chemical Solution by an electroless method, the annealed Ni-8Zn-8P film exhibiting better thermal stability, In the case of the Sn-3Ag-0.5Cu/Ni-8Zn-8P joint, the (Ni,Cu)(3)Sn-4 intermetallic compound can attach well to the Ni-8Zn-8P film after reflow. The line profile of the Zn element showed that the Zn was only distributed within the Ni-8Zn-8P film, indicating that Zn cannot be used as the diffusion barrier for Ni-diffusion to form (Ni,Cu)(3)Sn-4 IMC, in which no Zn was traced. Crown Copyright (C) 2009 Published by Elsevier Ltd. on behalf of Acta Materialia Inc. All rights reserved.