Frank,

2-5% is considered Low P
6-10% is considered Mid range P
11-14% is considered High P

Many of the boards we examined years ago that were fabricated with ENIG had Mid range P.  I'm not sure if I can find Zequm Mei's original ENIG work but he first thought that P content was the cause of BP failures since when he looked at fracture surface there was always high P content.  However,  you can't look just at a fracture surface because there will always be a high P content because at the interface you consume some Ni during the IAu processing and then more again during soldering.  So you might have a Mid range P ENIG but at the fractured surface it may look like High P.  Since then there has been lots of information indicating that P content isn't the root cause for BP.  I think I have the final HP paper on ENIG that Sequm was one of he authors and can send it if I find it.


Regards,
George
George M. Wenger
Senior Principal Reliability / FMA Engineer
Andrew Corporation - Wireless Network Solutions
40 Technology Drive, Warren, NJ 07059
(908) 546-4531 Office (732) 309-8964 Mobile
E-mail: [log in to unmask]


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Frank Kimmey
Sent: Thursday, May 24, 2012 12:22 PM
To: [log in to unmask]
Subject: [TN] Phosphorus content in Electroless Nickel

I know this may be difficult to commit to but what would you consider an acceptable percentage of Phosphorus in Electroless Nickel.
I am being asked to accept 7-10% and am not sure if this may lead towards Solderability issues.
Feedback from Chemists, Board Fabricators or anyone with an opinion is appreciated.
Thanks to a great group of minds,
FNK

Frank N Kimmey CID+
Manager - PCB Design
Powerwave Technologies Inc.
Mobile - 916-670-0645


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