(U.S.) Joint Electron Device Engineering Council Soild State Technology Association
Status
Scope
This test method applies primarily to moisture resistance evaluations and robustness testing, and
may be used as an alternative to unbiased autoclave. Samples are subjected to a non-condensing,
humid atmosphere, similar to the JESD-22-A 10 1, "Steady State Temperature, Humidity and Bias
Life Test", but with a higher temperature. For the temperature limits defined by this procedure,
the test will typically generate the same failure mechanisms as those in an unbiased
"85 "C/85%RH" Steady State Humidity Life Test, but caution must be used if higher
temperatures are considered since non-realistic failure modes can be generated. The use of a
non-condensing environment avoids many irrelevant external failures, e.g., pin-to-pin leakage or
lead corrosion. However, because absorbed moisture typically decreases glass transition
temperature for most polymeric materials, the combination of high humidity and high
temperature (> Tg) may produce unrealistic material failures. Thus, caution is needed if and
when Unbiased HAST is required for reliability or qualification purposes.