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January 1998

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Tue, 20 Jan 1998 08:54:32 -0500
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Over the past 2 months we have been experiencing and increase in the number
of opens on several different fine pitch QFPs.  We believe the problem is
due to poor wetting to the component leads.  On a typical 304 QFP we find ~
5-10% of the cards have 1 or more lead which is open.  Optically the open
lead has a coarse, grainy finish, and is surrounded by good joints where
the lead finish has a very fine grain structure.   SEM/EDX analysis of the
finish reveals the presence of large (~20-40 um) Sn grains with Pb
segregated between the grains.  Analysis has not shown any signs of gross
contamination.

Is there anyone who has seen a similar phenomena and might have a possible
corrective action?  I can email anyone a picture if you're interested.

Thank you

Jason Bragg

 Jason P. Bragg,
Celestica Inc.
                    Component Failure Analysis
                         844 Don Mills Road, 20/429
                    Materials Analytical Lab
          North York, Ontario, M3C 1V7
                    Internet: [log in to unmask]
          Tel: (416) 448-6203

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