No, you are all wet. The sudden vaporization of moisture in plastic or epoxy
can pop the die off the carrier, pull wire bonds off the die, crack the
package and expose internal workings of the device, and more. Popcorning is
a good name. Recently, I saw a device just like the one you describe. A
ceramic with gold wire bonds, cavity filled with epoxy as an encapsulate.
The epoxy absorbed water which erupted during reflow and created a large
void in which the bond wires bent and made unwanted electrical contact. . .
with very weird symptoms.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Dehoyos, Ramon
Sent: Tuesday, June 21, 2005 9:27 AM
To: [log in to unmask]
Subject: Re: [TN] Moisture sensitivity levels...


        I may be totally wet but my assumption has been that there needs to
be a cavity such as in the QFPs or DIPs for enough moisture to create enough
pressure to pop a device. Based on this assumption, perhaps if the cavities
were potted after wire bonded there would not be a need for MSL nor the
prohibition against ultrasonic cleaning. I have seen some components with a
jelly like material inside over the electronic device.............. Just a
thought.
        Ramon

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