Dear L. Ramesh,
Warpage can be caused by many different things. One frequent cause that I
have run into is poor board design. It is important to keep the amount of
copper on each layer balanced about the middle of the board when viewed
from the edge. As an example, a four layer board with plane layer(s) should
be:
Layer one, signal
Layer two, plane layer (Power of Ground)
========================================= Middle of Board
Layer three, plane layer (Ground or Power)
Layer four, signal
If the circuitry NEEDS only ONE plane layer (three layer board), duplicate
that layer to provide the necessary balance (make it four layers).
There should always be an even number of layers in a multi-layer board.
There can also be other issues such as the grain direction, size and
structure of the pre-preg material. One of the board fabricators on TechNet
will have to explain those issues to you. Other causes could be how the
board is cooled after lamination.
I hope this helps.
Charlie B.
Please respond to "TechNet E-Mail Forum." <[log in to unmask]>; Please respond
to "L. RAMESH" <[log in to unmask]>
To: [log in to unmask]
cc: (bcc: Charles Barker/US/I-O INC)
Subject: [TN] Warpage
Dear Technetters,
I would like to know the possible causes for warpage and its control. All
suggestions is gratefully acknowledged.
Regards,
L. RAMESH, Tel: +91-8221-26618, 26619,
Indal Electronics Ltd., 26375, 26584 Extn: 345
No.12 A, Industrial Area, Fax: +91-8221-26641
Nanjanagud 571 301, email: [log in to unmask]
District Mysore, INDIA. web site:www.indalpcb.com
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