The following article is a guide for handling moisture sensitive surface mount devices and is based on the IPC/JEDEC industry standard J-STD-033 available from JEDEC.
Non-hermitically sealed electronic components absorb moisture from the environment. During solder reflow assembly the moisture in devices expands rapidly and cause materials stress that may degrade material interfaces.
2. Storage & Handling Guideline:
To prevent damage in moisture sensitive devices due to absorbed humidity, the devices must be stored in a low humidity environment and mounted within a specified exposure time to normal atmospheric conditions.
The most common method for storage and shipping moisture sensitive devices in a low humidity environment is according to the J-STD-033 Standard, in sealed moisture barrier bags with desiccant and containing a Humidity Indication Card (HIC).
The sealed moisture barrier bag will also have a special moisture sensitivity label indicating the MSL classification level number, showing the floor-life (exposure time to ambient factory conditions) information and Bake-out information.
If a device was exposed to excess humidity, whether a HIC indicated over exposure or if devices exceeded their allowable floor-life, the devices must be dried out by processing the devices through a bake-out procedure.
Please refer to the complete J-STD-033 for additional details.