Controlling Bulk Cu6Sn5 Nucleation in Sn0.7Cu/Cu Joints with Al Micro-alloying
File(s)
Author(s)
Xian, JW
Belyakov, SA
Gourlay, CM
Type
Journal Article
Abstract
We show that dilute Al additions can control the size of primary Cu6Sn5 rods
in Sn-0.7Cu/Cu ball grid array joints. In Sn-0.7Cu-0.05Al/Cu joints, the
number of primary Cu6Sn5 per mm2 is 7 times higher and the mean threedimensional
length of rods is 4 times smaller than in Al-free Sn-0.7Cu/Cu
joints, while the area fraction of primary Cu6Sn5 is similar. It is shown that
epitaxial nucleation of primary Cu6Sn5 occurs on d-Cu33Al17 or c1-Cu9Al4
particles, which are stable in the Sn-0.7Cu-0.05Al melt during holding at
250C. The observed facet relationships agree well with previously determined
orientation relationships between d-Cu33Al17 and Cu6Sn5 in hypereutectic SnCu-Al
alloys and result in a good lattice match with<2.5% lattice mismatch
on two different interfacial planes.
in Sn-0.7Cu/Cu ball grid array joints. In Sn-0.7Cu-0.05Al/Cu joints, the
number of primary Cu6Sn5 per mm2 is 7 times higher and the mean threedimensional
length of rods is 4 times smaller than in Al-free Sn-0.7Cu/Cu
joints, while the area fraction of primary Cu6Sn5 is similar. It is shown that
epitaxial nucleation of primary Cu6Sn5 occurs on d-Cu33Al17 or c1-Cu9Al4
particles, which are stable in the Sn-0.7Cu-0.05Al melt during holding at
250C. The observed facet relationships agree well with previously determined
orientation relationships between d-Cu33Al17 and Cu6Sn5 in hypereutectic SnCu-Al
alloys and result in a good lattice match with<2.5% lattice mismatch
on two different interfacial planes.
Date Issued
2015-10-16
Date Acceptance
2015-09-23
Citation
Journal of Electronic Materials, 2015, 45 (1), pp.69-78
ISSN
1543-186X
Publisher
Springer
Start Page
69
End Page
78
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/s11664-015-4092-y
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
Pb-free soldering
grain refinement
intermetallics
crystal growth
orientation relationship (OR)
heterogeneous nucleation
SN-CU
SOLDER ALLOYS
PHASE
ETA-CU6SN5
ADDITIONS
GROWTH
Publication Status
Published