The Influence of Cu on Metastable NiSn4 in Sn-3.5Ag-xCu/ENIG Joints
File(s)
Author(s)
Belyakov, SA
Gourlay, CM
Type
Journal Article
Abstract
We have investigated the effect of small amounts of Cu on suppression of
metastable bSn-NiSn4 eutectic growth in solder joints between Sn-3.5Ag-xCu
solders and Ni-based substrates. For Sn-3.5Ag/electroless nickel immersion
gold (ENIG) and Sn-3.5Ag/Ni solder joints we showed that the eutectic mixture
contains bSn, Ag3Sn, and metastable NiSn4. It was found that addition of
only 0.005 wt.% Cu to Sn-3.5Ag-xCu/ENIG or Sn-3.5Ag-xCu/Ni joints promoted
formation of a stable bSn-Ni3Sn4 eutectic and that both Ni3Sn4 and
NiSn4 occur in the eutectic at this Cu level. We also showed that for complete
prevention of formation of metastable NiSn4 during eutectic solidification of
the solder joint, addition of at least 0.3 wt.% Cu was required.
metastable bSn-NiSn4 eutectic growth in solder joints between Sn-3.5Ag-xCu
solders and Ni-based substrates. For Sn-3.5Ag/electroless nickel immersion
gold (ENIG) and Sn-3.5Ag/Ni solder joints we showed that the eutectic mixture
contains bSn, Ag3Sn, and metastable NiSn4. It was found that addition of
only 0.005 wt.% Cu to Sn-3.5Ag-xCu/ENIG or Sn-3.5Ag-xCu/Ni joints promoted
formation of a stable bSn-Ni3Sn4 eutectic and that both Ni3Sn4 and
NiSn4 occur in the eutectic at this Cu level. We also showed that for complete
prevention of formation of metastable NiSn4 during eutectic solidification of
the solder joint, addition of at least 0.3 wt.% Cu was required.
Date Issued
2015-08-20
Date Acceptance
2015-07-25
Citation
Journal of Electronic Materials, 2015, 45 (1), pp.12-20
ISSN
1543-186X
Publisher
Institute of Electrical and Electronics Engineers (IEEE)
Start Page
12
End Page
20
Journal / Book Title
Journal of Electronic Materials
Volume
45
Issue
1
Copyright Statement
© The Minerals, Metals & Materials Society 2015. The final publication is available at Springer via http://dx.doi.org/10.1007/s11664-015-3964-5
Sponsor
Nihon Superior Co Ltd
Engineering & Physical Science Research Council (EPSRC)
Grant Number
N/A
EP/M002241/1
Subjects
Science & Technology
Technology
Physical Sciences
Engineering, Electrical & Electronic
Materials Science, Multidisciplinary
Physics, Applied
Engineering
Materials Science
Physics
Microstructure
Pb-free soldering
metastable
NiSn4
intermetallics
solidification
INTERMETALLIC COMPOUND GROWTH
SN/NI INTERFACIAL REACTIONS
LEAD-FREE SOLDERS
NI-SN
ELECTROPLATED-NI
TEMPERATURE
SUBSTRATE
KINETICS
SN-3.5AG
MICROSTRUCTURE
Publication Status
Published
Date Publish Online
2015-08-20