Handling Moisture Sensitive Devices

1. Introduction:

The following application note 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.