Hi Ioan - there are numerous studies on how copper will diffuse thru gold. 
I recommend that you contact/google the connector fabricators as they 
would be an immediate source of published reports. The diffusion of copper 
thru the gold would also degrade the solderability of the pins so, at a 
minimum, you can use the IPC JSTD -002 conditioning recipe (155C bake for 
4 hours) to get an initial measurement of degradation. Understanding what 
happens in the long term is not an easy assessment and dependent on the 
product use environment.

Dave Hillman
Rockwell Collins
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From:   Ioan Tempea <[log in to unmask]>
To:     <[log in to unmask]>
Date:   10/23/2012 07:43 AM
Subject:        [TN] Ni barrier thickness - Part II
Sent by:        TechNet <[log in to unmask]>



Dear Technos,

I guess you had all already guessed where I'm trying to get at: I have Cu 
diffusion at the surface of the Au on some connecting pins and can't 
assess the effect on long term reliability.

So here comes the second question: are there any studies / rules of thumb 
that could say how much of the Au surface may be lost without any negative 
impact on the functionality? I definitely got the message that everything 
is application related, but just trying my luck...

Or, anybody has an idea how could I test the long term reliability in this 
situation?

Thanks,

Ioan Tempea, ing.
Ingénieur principal de fabrication / Senior Manufacturing Engineer
[signature002]<http://www.digico.cc/>

950 RUE BERGAR, LAVAL, QC, H7L 5A1<http://g.co/maps/2gh3f>
T+ 1 (450) 967-7100, EXT244
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Entreprise manufacturière / Gestion du capital humain


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