RE>Spots on Cu surfaces after OSP coating    3/6/97

Hi Dave,

We had this same problem three years ago when we first implemented OSP boards
into our products.  In our case, the problem was traced to the boards not
being dried completely before packaging.  The blackened areas were found to
not solder well.  Problems were especially prevalent around areas with small
vias, where processing and rinse solutions can be trapped.  Processing on
lines with automated dryers also tended to have more problems than those
where a post bake operation was used.  

Hope this helps!

Regards,
Greg Bartlett
Mercury Computers Systems
Chelmsford, MA
[log in to unmask]

--------------------------------------
Date: 3/6/97 2:19 PM
To: Greg Bartlett
From: [log in to unmask]
We've experienced a problem with OSP coated product
after the product has been shrink-wrapped and sits in
storage for a period of days. Dark blueish-black spots
appear on the surface of many pads and annular
rings. We have no idea what causes this. We
refer to it as the "fungus" since it closely resembles
what you might see on an orange after a month in your
refrigerator.

Has anyone had any experience with this? Our OSP
provider has no idea what it could be. Our
experimentation has yielded no info. We haven't been
able to consistantly reproduce the problem.

Thanks,

Dave
[log in to unmask]


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Subject: Spots on Cu surfaces after OSP coating
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