Franklin,
we have seen something like this.
For some time we were believing it was a problem in the copperplating and
increased filtration amo.
Eventually we found out that it had origin in sudden precipitation of
palladium-colloids in our direct plating process. These particles were
square or rectangular with rounded edges.
Changes in cleaning procedures and also filtration helped on this one.
With best regards
--
Jan Thuesen, Process Engineer
Chemitalic A/S
Egebjergvej 128
DK-8700 Horsens
76 28 70 00 Fax: 76 28 70 95
http://www.chemitalic.dk/
-----Oprindelig meddelelse-----
Fra: Gary McCauley [mailto:[log in to unmask]]
Sendt: 15. marts 2002 13:57
Til: [log in to unmask]
Emne: Re: [TN] Unusual plated 'stuff' on copper surface
Franklin,
I have seen two things cause this. One is a relatively low level of carrier
in the plating bath.
The other is from years ago when we found fungi growing in our additive.
For whatever reason,
it was conductive enough to plate with the copper. Instead of rod shaped
however, it was
spiral like a miniature bed spring embedded in the coppper.
Gary McCauley
PC Boards, Inc.
Chanute, Ks
This past January we began seeing unusual 'growths' ((for lack of better
descriptive wording)) on the surface of panels after copper II, they are
typically observed on one end of the panels, often only a couple panels per
tankload exhibit this.
These 'growths' look like fine strands of metal of fabric fibers, they are
clustered together like someone poor shavings there, and plated over them.
If any of you recall pics of those bacteria found in that Mars asteroid from
the Antarctic, they appear similar to that (not saying we have bacteria
growing in our baths of course). Occasionally we see this out towards the
center of panels, I don't believe we have ever seen all panels in a tankload
exhibit this either. This condition is observed on one or two loads per day
(out of about 20 - 30), some days not at all.
We started seeing this in one bath (of three in house) until recently it
appeared in another bath simultaneously.
Any help on this would be greatly appreciated as our process engineers, lab
techs, and suppliers are baffled.
Thanks,
Franklin D Asbell
Network Circuits, Inc.
Irving, Texas 75061
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