Interfacial reactions between high-Pb solders and Ag
Journal
Journal of Alloys and Compounds
Journal Volume
509
Journal Issue
8
Start Page
3509
End Page
3514
ISSN
09258388
Date Issued
2011
Author(s)
Abstract
Interfacial reactions between high-Pb solders (Pb-10Sn, Pb-5Sn, and Pb-3Sn, in wt.%) and immersion Ag layer at 350 °C are investigated. Upon decreasing the Sn concentration from 10 wt.% to 5 wt.%, the reaction product formed at the solder/Ag interface changes from the Ag3Sn phase to the Ag 4Sn phase. When the Sn concentration reduces to only 3 wt.%, the reaction product is the Ag4Sn phase at the initial stage of reaction but transforms to the (Ag) phase dissolved with Sn at the later stage of reaction. Pb penetrates across the (Ag) phase via grain boundary and forms a continuous Pb-rich layer between the (Ag) phase and the bottom Cu layer. The correlation between the phase transformation and the solder composition is discussed based on the calculated Sn-Pb-Ag isothermal section. © 2010 Elsevier B.V. All rights reserved.
Subjects
Diffusion
Intermetallics
Liquid-solid reactions
Metals and alloys
Microstructure
SDGs
Type
journal article