Electronic components may be sensitive to the effects of moisture ingress. Evolution of miniaturized devices such as fine-pitch QFP devices and ball grid arrays (BGA) coupled with RoSH requirements for lead free processes, has increased concern for moisture sensitivity failure. IPC/JEDEC J-STD-020 defines the classification procedure for moisture-sensitive components, i.e., non-hermetic packages made from moisture-permeable materials such as plastic.

When components are exposed to the elevated temperatures during reflow soldering (260deg C), moisture trapped inside plastic surface mount devices (SMD) produces enough vapour pressure to damage or destroy the device. Common failure modes include internal separation (delamination) of the plastic from the die or lead-frame; wire bond damage; die damage; and internal cracks. In extreme cases, the component will bulge and pop (often referred to as the "popcorn" effect).

Final storing and shipping in a controlled atmosphere is achieved through the use of Moisture Barrier Bags (MBB’s), Desiccant and Humidity Indicator Cards. Finally the MBB’s are hermetically sealed under vacuum to prevent moisture absorption from the ambient environment, thus maintaining the devices in a dry condition until used. Shelf life when packaged in this condition is typically 1 year.