The Definitive Guide to an Electronic Assembly Design Review / 17
When performing failure analysis, it is important to not
limit the analysis to assemblies that failed preliminary
tests. In such a scenario, the test would only determine
what does not work before the product ever hits the
field, when your ultimate goal is to determine the
reliability of a product in its use environment. Failure
analysis should include studying test failures, as well as
field returns (if they exist), to accurately understand
field environments as well as exhaustively identify use
cases that may not have been considered in initial
reliability qualifications.
In a design review, failure history can often provide significant insight into the root cause of failure. For
example, if failures occur quickly in the field, the root cause may be linked to a manufacturing-related issue.
Similarly, if dendritic failures are encountered, it may be a cleaning or handling issue in manufacturing or an
environmental exposure issue.
Failures during a testing protocol need to be analyzed so that the root cause can be ascertained and acted
upon. For example, HALT testing searches for failure, fixes it and resumes the test. Doing so helps determine
the design's margins with respect to the test parameters.
9
Perform Failure Analysis on Test Failures and Field Returns to Initiate Feedback Loop
