Schlumberger-Private
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Dear Technetters,
What are people using to inspect co-planarity of gull wing devices (fine pitch QFPs and SOICs) prior and post soldering? I am especially interested in techniques that can detect small differences in z axis causing the lead to just "sit" on solder after assembly and cause premature failure or intermittent operation. I was looking on line and found some inspection mirrors for pre-soldering inspection but not a whole lot else. I would be grateful if you can share your experiences regarding what other techniques work.

On a related topic; what is the general feeling about correcting coplanarity issues by using reworking templates to push the leads back to their intended position. I do not like it as it may damage the seal around the lead and the body depending on the extent of rework. Can you point me to any studies done on this topic that highlight the failure modes resulting from this practice?

Thanks,
Amol


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