Hi Ioan! I don't have any experience with the ImAg over electroless nickel 
but the IPC 4-14 committee hasn't changed the IPC-4553 specification to 
include it as a finish. Section 1.2 of the IPC-4553 specification states " 
IAg is a thin immersion deposit over copper....." so ImAg over electroless 
nickel isn't listed. Some of the requirements of the IPC-4554 
specification could certainly be applied. The electroless nickel layer is 
certainly not necessary for soldering applications (and IMHO is a 
detriment in terms of solder joint configuration). Maybe the finish is 
intended for wire bonding applications.  I'll bring your comments and the 
finish to the committee's attention.

Dave Hillman
Rockwell Collins
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Ioan Tempea <[log in to unmask]> 
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02/12/2009 08:27 AM
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[TN] ENIS






Dear Technos,
 
I have a PCB spec here spelling ENIS (electroless Ni Immersion Ag) as a 
surface finish. What is this and what is the use of adding the Ni layer? 
Google came back with this link
http://www.4pcb.com/index.php?load=news&page=index&op=news_view&news_id=39 
, so there are people actually doing this.
 
To make it more complicated, the specification line ends with <per 
IPC-4553>... and the copy I have does not mention anything about Ni.
 
Weird, isn't it?
 
Thanks,
 
Ioan Tempea, ing.
Ingénieur Principal Fabrication / Sr. Manufacturing Engineer 
 
30 ans déjà! - Already 30 years!
950 rue Bergar, Laval, Québec, H7L 5A1
t : 450-967-7100 ext : 244
Mtl : 514-990-5762
f : 450-967-7444
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www.digico.cc <http://www.digico.cc/> 
P N'imprimer que si nécessaire - Print only if you must
 

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