Meaning
Graded classification for moisture sensitivity defines how long a surface mount device can be exposed to ambient room conditions before it must be baked or sealed. The moisture sensitivity level rating determines the handling procedures on the factory floor to prevent damage during the soldering process. Higher ratings indicate that a part absorbs water quickly and requires strict environmental controls.
Handling Requirement
Technicians must track the total time a component spends outside of its protective moisture barrier bag. If a part exceeds its moisture sensitivity level time limit, it must undergo a drying process in a low temperature oven to remove any absorbed humidity. This prevents the moisture from turning into steam and cracking the package during the heat of reflow soldering.
Packaging Standard
Manufacturers ship sensitive parts in vacuum sealed bags that include a desiccant and a humidity indicator card. The moisture sensitivity level of the device is clearly printed on the label to alert the receiving team of the necessary storage conditions. Specialized moisture barrier bags are used to prevent the entry of water vapor during long distance shipping and warehousing.
Failure Prevention
Cracking and internal delamination are the primary risks associated with improper management of these parts. When a moisture sensitivity level is ignored, the resulting damage can be microscopic and may not be detected until the product is in the hands of the customer. Maintaining a dry environment for all sensitive electronics ensures the long term durability of the assembled circuit board.
