Abstract: For the hermetic packages with internal free volume less than 0.01 cm³, the environmental humidity impacts on the moisture content of this types of devices will be more serious, and the moisture content could be over 2% and tends to saturation in a short storage period. In the process of helium inside-out leak testing, the measured leak rate would drop quickly in the dwell time between release of pressure and leak detection. The issues of the loose criteria of the equivalent standard leak rate for this type of devices were discussed, and the measure of evaluation on their hermeticity performance was proposed.