Get To Know Standard-033B.1
Moisture sensitive devices or MSDs represent one particular area the industry continually and diligently pursues, and the proof of that is IPC/JEDEC J-STD-033B.1 Standard. The experts authoring this Standard have studied the ill effects of MSDs over time and have published a long list of procedures for properly handling, packaging, and shipping MSDs.
Basically, ICs and other components act like a sponge, and if they have semi-permeable membranes, moisture from the air can get into those devices. As a result, rapid outgassing occurs when those devices are rapidly heated during reflow or rework. Sometimes, excessive outgassing causes the so-called ‘popcorning’ effect, which can damage a component’s internal structure.
Check out the November issue of PCD&F/Circuits Assembly Magazine and read our article to get more details on this industry wide issue. Our article covers a number of key aspects of how a savvy contract manufacturer (CM) should deal with MSDs.
In the meantime, here are a few tips you can use to get a good handle on MSDs so you are better prepared when you submit your next PCB project to your CM.
- Foremost, assure that the CMís assembly personnel are well-trained and up to date on STD-033B.1.
- Get a good understanding of the four major materials and techniques used to help protect and control MSDs ñ moisture barrier bag (MBB), desiccant, humidity indicator card (HIC), and moisture sensitive caution label.
- Make sure your CM is closely monitoring suppliers’ poorly packaged and shipped MSDs.
- Ensure your operations are also applying STD-O33B.1 practices and procedures.
- Check to find out if your CM is maintaining an MSD control event logbook to record specific problems and solutions.
- Look to see if your CM is monitoring factory ambient conditions. If room temperature is more than 30∞ C or 86∞ F or room relative humidity is more than 60 percent, floor life indicated on the MS label is no longer applicable and must be de-rated.
Protecting and controlling MSDs on the assembly floor takes into account a great number of large and small procedures and important steps. Violating, ignoring, or oversight of any one or a series of these precautions results in either costly rework or latent PCB defects. Therefore, it is important for you, the OEM, to fully understand how best to sidestep MSD problematic areas.