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April 2005

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Subject:
From:
R Sedlak <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, R Sedlak <[log in to unmask]>
Date:
Wed, 20 Apr 2005 16:53:04 -0700
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Mr. Olsen:

You might want to give us an idea of what is going on in the plating line, to give us some clues to discuss the situation.

Back in the days... perhaps WAY back in the days, when manual plating lines were common, and a microetch was commonly used prior to plating, (and this can apply to acid cleaners, in the extreme case) the platers would allow panels to sit in the rinse, or in the Sulfuric Acid pre-dip for extended lengths of time, while they went to lunch, or for a coffee break.

The Copper in solution (Cu++, Cupric Copper) would react with the Copper metal, and create a Cuprous (Cu+) insoluble deposit on the metal, which in those days would mean the Tin/Lead plating (the next step) was not adherent, and it would evidence as "dewetting", but if you were plating Copper instead of Tin/Lead, it would give you peeling.

If you have a microetch, or acid cleaner, I would look at residence time, and Copper content, in any rinse, or other pre-treatment, after the microetch or acid cleaner, and prior to Copper plating.   The key things to watch out for are extended residence time and/or high Copper loading in solution.
If you have a Sulfuric acid pre-dip, change it often to keep Copper loading down, and do not give the panels more than 30 seconds in the dip.

And, if you do track this problem down, and find the answer, share it with us please.

Thanks

Rudy Sedlak
RD Chemical Company


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