Hi Steve! Another good paper that emphasizes the need for proper bath
chemistry control is "Study of the Mechanism Responsible for "Black Pad"
Defects in PCBs using Electroless Nickel/Immersion Gold as a Final Finish",
IPC EXPO 2001 Proceedings, author: K. Johal, paper S10-4-1.

Dave Hillman
Rockwell Collins
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Steve Gregory <[log in to unmask]>@ipc.org> on 07/22/2002 11:20:40 AM

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Subject:    Re: [TN] Au-Ni coating


I've never heard/read anything about uncured soldermask either. I've got a
pretty good *.PDF file authored by Nicholas Biunno of Hadco, and presented
at the '99 IPC Printed Circuits Expo that doesn't mention anything about
soldermask...is this something new?

-Steve Gregory-


Bruce:

My understanding of Black Pad was it is caused by too much phosphorus in
the nickel (as I recall) plating bath.
Solder mask contamination is a new one for me.
With mask going on after the gold, how does it contaminate the nickel? Mask
should not come in contact with the nickel at all in my experience

I am interested in learning all nuances of black pad causation.
Would appreciate your comments.

Charlie McMahon

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