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The problem with coeficients of expansion of different substrate materials
has been a problem in the printed wiring board industry for many years. The
use of Kevlar, Copper-Invar-Copper and Thermount has been common. The X and
Y expansion differences between the substrates in our electronic components
and the printed wiring substrates has cause millions of dollars of
additional expense in the use of exotic materials in our printed wiring
substates. This is not a simple nor cheap problem to address and many
problems have been realized by this situation. It is much better to utilize
plastic components to place on plastic boards.
Phil Elias
Honeywell Air Transport Systems
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From: [log in to unmask]
To: [log in to unmask]; [log in to unmask]
Subject: FAB: Heat Expansion
Date: Wednesday, June 26, 1996 9:11AM
Has anyone had problems with the different rates of expansion among IC chips
made of ceramic material, copper for traces/pads, and say FR4?
The result would be cracks in the traces/pads?
Doug
[log in to unmask]
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