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Date: | Thu, 15 Feb 1996 17:51:42 -0600 |
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At Hitachi, we are considering moving to BGA technology during our
next model design phase. We are not very familiar with the
manufacturing process for this technology. We have come up with a
question we have not yet been able to resolve (as follows).
Solder joints on QFP's resist cracking due to thermal expansion
because the leads have some give due to a "spring" effect. With BGA's
there is no give between the board and the part except for the solder
joints. If there is a difference between the board's coefficient of
expansion and the part, the solder joint will crack.
1. Has anyone experienced this problem? How do you resolve it?
2. We are considering some sort of sealant material to protect the
solder joints and provide some thermal relief. Does anyone have
any good ideas for materials?
Anyone who can do a data dump on this for me will be greatly
appreciated! Thanks in advance,
Roger Held
Hitachi Computer Products
Norman, OK
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