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Date: | Tue, 15 Oct 96 16:34:22 cst |
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Hi Ed -
I suggest you run a FTIR scan (Fourier Transform Infrared) on your
unknown film. The FTIR test results should give you the chemical clues
to determine the source of the film. I suggest you also talk to Doug
Pauls ([log in to unmask]) - he could suggest several other techniques
that may be beneficial. Without knowing what type of flux materials
and cleaning systems you are using a guess on what the film could be
might be totally skewed. Can you provide more process type details?
Dave Hillman
Rockwell Collins
[log in to unmask]
______________________________ Reply Separator _________________________________
Subject: SMT Solder Joint Film
Author: [log in to unmask] at ccmgw1
Date: 10/15/96 2:17 PM
We are noticing a film on our SMT solder joints. It doesn't seem to
affect ionic cleanliness or conformal coating adherence, but can only
be removed mechanically with a brush or Q-tip. It has a slightly
yellowish color in most cases and appears powdery. Is this
contamination from the PWB pads or part leads floating to the top, or
a compound derived from the solder paste (63/37 RMA)? Any insight
into what this contamination is would be appreciated.
Thanks.
Ed Knowles
Lockheed Martin Astronautics
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