Hi Pascal! Do you have any pictures that you could send to Steve for
posting? Very curious to see what the electromigration and tin whiskers
look like!
Dave Hillman
Rockwell Collins
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Pascal Guiheneuf
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COM> To
Sent by: Leadfree [log in to unmask]
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Subject
[LF] Electromigration, high density
01/27/2006 07:33 current, Lead-free connectors
AM
Please respond to
"(Leadfree
Electronics
Assembly Forum)"
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>; Please respond
to
Pascal Guiheneuf
<[log in to unmask]
COM>
Hello,
I am looking for information around an electromigration topic : due to
Lead-free, we moved, on a power connector, from a SnPb plating to a Tin
(10um) plating with a Ni barrier (5um) on copper; after 700h of a 2000
hours 50°C, 7 Amps, 70°C ambient temperature, we are facing failures. RCA
leads to electromigration in high current densities, accompanied with other
collateral damages (Ni3Sn4 intermetallic rapidly growing, Tin particles
(maybe due to excess voiding or due to fretting corrosion on Tin softened
by the actual temperature), possibility of arc (voiding)..), all mechanisms
leading to higher resistivity, temperature increasing, and catastrophic
failure as soon as the temperature is beyond 130°C (plastic limit). For
your information, we have also seen Tin Whiskers during the same
experiment. The first time we succeeded in Tin Whiskering !
We would like to change to a power connector Gold plating with Ni barrier.
Is anyone of you aware of anything here, relative to high current
densities, to Gold electromigration, etc...? I couldn't find the data
around the Black's law which defines the EM, relative to Sn or Au, and
request your help.
Very cordially,
Regards,
Pascal Guihéneuf
Nortel Wireless
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