Sumxp

It is likely the thickness of the gold is inadequate and the underlying
nickel has oxidized. I would measure the gold thickness (XRF) and compare
it to the minimum specified. The silver color after erasing is most likely
the nickel that is under the gold and with the oxides removed.

There are many other alternatives these days to ENIG such as immersion
silver. Have you evaluated into any of these?

Best regards

Lee

J. L. Parker Ph.D.
JLP Consultants LLC
(804) 779 3389


Best regards

Lee

J. L. Parker Ph.D.
JLP Consultants LLC
(804) 779 3389


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of sumxp
Sent: Friday, January 13, 2006 10:48 AM
To: [log in to unmask]
Subject: [TN] enig bad board

Hi,

We noticed few ENIG bga pads black in color instead of gold.It turn silver
when use eraser to remove away the black color pad.What is the defect
mode?
Any reliability issue?Is it advisable to continue using these pcbs?

Thanks......

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R

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