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Date: | Mon, 2 Jun 2008 11:29:06 -0700 |
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It's actually easier than trying to get a co-planer injection on something
like a BGA package with a heat spreader.. You design the tooling so the
resin doesn't inject into those areas. All you are doing is raising the
injection plane up by 3 mils, so presumably the tooling has a flat base with
pockets in it to accommodate those raised pads
John
John Burke
(408) 515 4992
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of bob wettermann
Sent: Monday, June 02, 2008 9:18 AM
To: [log in to unmask]
Subject: [TN] QFN "Bumped" Pad Construction
Dear Technetters:
Since this question could not be raised on "How It's Made" I thought we
would pose it here:
We have recently come across a few QFN packages where there are raised pads
(about 3 mils from the bottom surface of the QFN) on the bottom of the
device.
Our questions are related to the following:
How are these "raised bump" leadless packages fabricated such that these
bumps are raised to a different z axis plane then the bottom surface of the
device?
Regards
Bob Wettermann
PH 847-767-5745
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