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Wed, 20 Aug 2003 10:58:50 -0700 |
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RE: [TN] FAB: Single vs Double Ply Multi-Layer ConstructionGranted, but lets
take resin starvation out of the equation. Putting 1080 as an example in my
original message may have been a bad choice. Lets debate single vs double
given sufficient resin content in both options. Cost is of course the
driving factor towards single ply but I am looking for "proven" negatives.
John
-----Original Message-----
From: Frank Kimmey [mailto:[log in to unmask]]
Sent: August 20, 2003 10:41 AM
To: TechNet E-Mail Forum.; John Parsons
Subject: RE: [TN] FAB: Single vs Double Ply Multi-Layer Construction
Hey John,
The best reason I could give to stay away from single ply prepregs would
be resin starvation.
A single ply of 1080 is about 3.5 mils thick before pressing and 2.5 mils
after pressing, that only leaves about .5 mils per side to fill copper to
substrate voids.
Since 1/2 oz copper is .7 mils thick the math doesn't come out to good.
I have seen (though didn't like) single ply construction done between
planes (no thermals).
There could be arguments for single ply lamination but for reliability
(reduced delam possibilities) I would always recommend minimum 2 plys.
Since 1 ply of 1080 tends to press to about 2.5 mils you could probably
still get away with 2 plys of 106 at about 3 mils and have much better
reliability.
Hope it helps.
Good Luck
FNK
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