Case studies
electronics/chemical/ 3 weeks

SEM/EDS reveals lead-free solder voiding on a mil-grade PCBA

SEM/EDS reveals lead-free solder voiding on a mil-grade PCBA
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Problem
A defense electronics manufacturer had intermittent BGA failures on temperature cycling. Standard SPC data showed no anomaly.
Approach
Cross-sectional metallography through failed vs. passing joints; SEM imaging at 3,000×; EDS mapping of Sn, Ag, Cu and contaminants at the intermetallic interface.
Finding
Micro-voids concentrated at the pad-side intermetallic layer, correlated with a specific date-code of paste — vendor supplied out-of-spec flux batch.
Outcome
Paste vendor issued corrective action + credit; failed lot re-worked; test coverage expanded to include cross-section sampling on high-reliability builds.

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Long Island, New York based metallurgical testing lab serving aerospace, automotive, defense and other regulated industries since 1985.

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Metallurgists · Analysts · Since 1985