The ceramic packages do not absorb moisture as the plastic ones plus they are a lot stronger. The plastic packaging are the problematic ones.  The container strength, if one compares  different shapes of packages that use the same plastic type material and same lid glue, will directly depend on the lid area . The larger the lid area the better chances for rupture. The damage is done to the package lid ( pop corning ), not necessarily to the IC and  wire bonding. Once the lid pops, many different contaminants can enter in the IC cavity.
        Regards,
        Ramon
	
        	


-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Genny Gibbard
Sent: Friday, October 08, 2004 2:20 PM
To: [log in to unmask]
Subject: [TN] Moisture sensitivity


Just a question for interest sake.  Are there any general correlations
between package size, and lead numbers, and moisture sensitivity that can be
made?
For instance, do you think a 17.5mm square 44 lead 4.5mm thick package would
have less or more moisture sensitivity than a 16mm square 64 lead  1 mm
thick package.  The IC's have different functions.

Gut feeling, I think the 64 lead would have more sensitivity.  It is
smaller, with more and finer pitch outside connections.  As dimensions get
smaller, I think the danger of moisture doing damage goes up.  Also, since
there are more leads I feel that there are more locations that possibly
moisture could get in, as the potential for seal breaks is probably greater
at interfaces between plastic and metal?

Am I out to lunch in my general reasoning?

Just thought I would spice up Friday.

To all those Canadians out there, enjoy your turkey and pumpkin pie this
weekend.

Genny Gibbard (mailto:[log in to unmask])

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