Environmental Stressor
Assessment criteria for cyclic temperature humidity testing define the exact degradation thresholds for organic microelectronic packaging under high moisture conditions. The jesd22-b117 specification governs the acceleration factors applied to components during humidity stress testing to ensure the integrity of the polymer interface. It establishes the duration and the severity of moisture exposure cycles for devices before they undergo functional performance verification.
This method specifically targets the potential for delamination at the bond between the molding compound and the lead frame or silicon substrate. Engineers utilize these parameters to predict the operational life of components exposed to damp heat. The document limits the application to non-hermetic packages because moisture diffusion through solid plastic bodies remains the primary failure mode addressed by these procedures.
Cyclic Exposure
Loading sequences demand a precise transition between high humidity states and elevated temperature ramps to simulate ambient saturation in the field. Every cycle requires a sustained soak period where the relative humidity reaches a specific percentage while the dry bulb temperature maintains a stable plateau. The cooling phase occurs at a controlled rate to prevent condensation from creating artificial shorts or chemical leaching on the lead surfaces.
Rapid fluctuations inside the test chamber cause mechanical strain due to the mismatched coefficients of thermal expansion between the metal pins and the plastic encapsulation. Such differential expansion stresses the interface and creates pathways for water ingress. High humidity levels penetrate the matrix of the resin, leading to dielectric changes or electrolytic corrosion of internal metallic interconnects if the sealing process lacks sufficient refinement.
Performance Metric
Validation of the component reliability rests on the post-test visual inspection and electrical continuity verification. Testing protocols require the removal of superficial moisture before examiners identify cracks or internal separation within the package architecture. If the device passes the defined electrical thresholds after the moisture cycles, the batch maintains its rating for moisture sensitivity levels.
This standard confirms the durability of the packaging materials against the specific environmental risks associated with humid climates.
