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Reply To: | TechNet E-Mail Forum. |
Date: | Tue, 29 Sep 1998 08:00:00 -0400 |
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Are these "dimpled" BGAs? Are the component pads recessed below the bottom
surface? If so, perhaps you might try screening the flux instead of
dispensing. This might give you a better flux deposit without voids.
Jim Marsico
AIL Systems Inc.
(516) 595-5879
[log in to unmask]
Fumiaki Shigeoka wrote:
My problem is dropping solder ball from BGA devices after ball attachment
process.
First, I suspected the temperature of reflow oven, but that was sufficient to
melt
solder ball. After reflow, some balls(5-10% of strip) are missing, and empty
pads
are not wetting or partially wetting.
I found voids in flux on pad before placing ball, so I guess the void will
expand
in reflow furnace, and ball doesn't touch to pad. I use dispensing system to
provide
flux, which sometimes contaminates air void to flux on pad.
Does anyone have any experiences and suggestions to solve this problem ?
Thanks in advance.
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