Hi Louis,

On an ENIG surface finish you are soldering to Ni not Cu so I would be very surprise if the type of copper plating under the Ni would impact solderability.  Do you have any photographs that show the reason you suspect there is a solderability difference?

Regards,
George
George M. Wenger
Failure Signature & Characterization Lab LLC
609 Cokesbury Road, High Bridge, NJ 08829
(908) 638-8771 Home (732) 309-8964 Mobile
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-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Louis Hart
Sent: Friday, May 31, 2013 3:18 PM
To: [log in to unmask]
Subject: [TN] solderability factors

TechNetters, In concert with colleagues, I have been conducting experiments to identify and assess the relative influence of some process factors and parameters on the performance of printed circuit boards with ENIG final finish in the J-STD-003B solder float test of S coupons.

These experiments have led me to conclude, or at least suspect, that the plated copper, on which the ENIG is deposited, has a highly significant impact on performance in the solder float test.

We have a DC copper plating line along with a Reverse Pulse copper plating line. Experimental results show significant difference in solder float testing between the lines. I had been looking at the book by Humpston and Jacobsen, Principles of Soldering, after having spent some time with the TechNet-referenced books by Manko and Klein-Wassink.

Humpston and Jacobsen's book, in the 2nd of the two chapters I read so far, appears to say plating technique can affect solderability. Maybe I'm misinterpreting something, since I'm often reading these things around 11 PM.

Anyone in the TechNet world able to help me understand if and how DC copper might solder differently from Reverse Pulse copper, after ENIG deposition?

Louis Hart
Compunetics
Monroeville, PA
USA
[log in to unmask]<mailto:[log in to unmask]>
412-858-1232


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