Vacuum Sealing Moisture Sensitive Device Packaging
Moisture Sensitive Devices (MSDs) require additional consideration when handling. These critical devices have a relatively short useable floor-life which sets a time limit on the overall exposure to moist air.
These components are supplied originally in a Moisture Barrier Bag (MBB) to prevent moisture transfer possible through normal packaging. They have the excess air removed, a desiccant added (to remove any moisture from the remaining air found within the bag) and also a Humidity Indicator Card (HIC) to evidence the condition of the devices when opened.
This means that once opened the devices are exposed to air and will start absorbing moisture!
Several solutions exist to correctly handle these devices, however the best solution will depend on your volumes of MSDs, your usage needs and your budget.
Dry Storage Cabinet
A Dry Storage Cabinet is the optimal solution for MSDs – simply store all your components in a monitored dry store with very low relative humidity (RH), however if you have a lot of components you will need to invest in multiple dry storage cabinets.
If you have a small quantity of these devices you can prolong the floor-life simply by resealing the packaging once you have removed the components you need – as you are only counting the “Open” time of the bag it will allow these components to be stored for a much longer time.
A Vacuum Heat Sealer can be used to remove excess air from the packaging, allowing it to be stored correctly until next needed.
There are broadly two types of Vacuum Heat Sealers – External Aspirators (use a pump to draw air out of the bag) and Tank Sealers which use vacuum to force the air out of the bag.
When repackaging MSDs it is necessary to follow the relevant standard for the device level (e.g. JEDEC-STD-033 or MIL-B-81705C). This will detail the vacuum required, the MBB thickness, the amount of desiccant and the type of HIC required.
When the useable floor-life of Moisture Sensitive Devices is reached you can use a Baking Oven to reset this floor-life. If you choose this method you would still need to consider how to store them after, either in a Dry Storage Cabinet or by repackaging in a Moisture Barrier Bag using a Vacuum Sealer.