Moisture Sensitivity Level

定义

Moisture Sensitivity Level (MSL) relates to the packaging and handling precautions for semiconductors devices. The MSL is an electronic industry rating that describes how long a moisture sensitive device can be exposed to ambient room conditions (approximately 30°C and 60% Relative Humidity) prior to being soldered in place.

Semiconductor devices absorb moisture and may be damaged during surface mount reflow, when moisture trapped inside the component expands. The expansion of trapped moisture can result in internal separation or delamination of the plastic from the die or lead-frame, wire bond damage, die damage, and internal cracks. In the most severe cases, the component will bulge and pop. This is known as the "popcorn" effect.

Moisture sensitive devices are packaged in a moisture barrier antistatic bag with desiccant and a moisture indicator card. The bag is vacuum sealed to protect the devices from moisture absorption prior to use.

IPC/JEDEC's J-STD-20: Moisture/Reflow Sensitivity Classification for Plastic Integrated Circuit (IC) SMDs defines eight levels MSL ratings. Components must be mounted and reflowed within the allowable period of time (floor life out of the bag) as defined by this standard.

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