Why be Concerned with Moisture?

…..and what to do to protect your valuable MSD inventory

Components will begin to absorb moisture from the air as soon as they are removed from protective storage (Moisture Barrier Bags, N2 Cabinets, Desiccating cabinets) and condensation will form on its surfaces. Within a fairly short time moisture will permeate the inside of the package. If reflow soldering is performed under these conditions, the moisture will form into vapor creating pressure inside the package that almost always results in internal damage to the part (cracks or ‘Popcorning’). Initially, no irregularities may be visible, defects can be difficult to detect, even if tested electrically. However corrosive ions may eventually find their way through the cracks, corroding and eventually destroying the circuitry inside the chips.

IPC/JEDEC J-STD-033a (July 2002) lays out very specific guidelines for MSD’s once they have been removed from MBB quality storage, regarding exposure times to various moisture levels in the production facility, and the approved methods for voiding the parts of that moisture. Some of these methods and procedures can become very confusing, and difficult to implement.

X Dry Cabinets are well equipped to deliver the constant < 5% RH that IPC/JEDEC J-STD-033a (July 2002) demands in order to be “considered equivalent to storage in a MBB with unlimited shelf life”. This allows for the return of parts NOT sealed in a MBB for safe storage. In fact dependent on the type of parts, the total exposure, and the total storage time in the X Dry Cabinet, floor life can be reset to zero. This is something that cannot be achieved with an N2 cabinet.

 

X Dry Desiccant Dry Cabinets are: