Genny, FYI, Mostek (if anyone remembers them) years ago had a problem that
arose from marking bad dice on wafers with a red marker. The ink contained
chlorine, some of which migrated to good dice, leading to corrosion of the
aluminium metallization while in operation. Lou Hart
-----Original Message-----
From: Genny Gibbard [SMTP:[log in to unmask]]
Sent: Friday, January 18, 2002 12:39 PM
To: [log in to unmask]
Subject: [TN] Silver component contamination
Happy Friday! (tappity, tappity - doing the Friday dance)
We have ceramic resonators with silver coating on several products. We
started handling those OEM boards with gloves during our test processes
because the customer expressed concern with skin oil contamination.
At times these components have been marked in house, for various reasons,
with a standard sharpie marker. In fact, at an early point in the
production schedule, the CM we were using at the time was marking them on
their own, because the resonators are so close in size they were having
trouble telling them apart and getting them installed in the right
locations
(due to tight time requirements, we got a shipment of bulk parts that were
being placed by hand). The marks looked like they were marker applied and
used a variety of dot and line patterns in various colours. We have never
noticed any harmful effect on their response, although build quantities
were
low.
Now someone on our production floor is asking whether the ink may be a
contamination that we should avoid. We have easily cleaned this marker off
of other surfaces with board wash. They wanted to know if they should
clean
the components with board wash. I think that if the marker is already on
there and a contaminant, don't compound it by rubbing board wash on it.
>From what I can tell, from the MSDS on the marker website, the ink is
primarily propanol/butanol/alcohol based. The board wash is alcohol based.
Chemistry is my weak subject. Is alcohol - related substances on silver
coated components a concern?
Genny Gibbard (mailto:[log in to unmask])
Product Transition and Support
Wavecom Electronics Inc.
202 Cardinal Crescent
Saskatoon, SK, Canada
ph: (306) 955-7075 ext. 229
fax: (306)384-0086
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