Hi,

If appropriate to your volume throughput's then use manual X-Ray inspection
or get an automatic X-Ray inspection machine.  Also verify the correct
solder
paste print (height & volume); placement accuracy of the BGA and of course
the reflow profile;  If prototype build then manual X-Ray would be the best
option for BGA solder joint inspection;

Basically there may be a dry joint on the BGA where pressure is making
contact.

Hope this helps;

Thanks,
Douglas I McCall

-----Original Message-----
From: Liew, Sen Joon [mailto:[log in to unmask]]
Sent: 07 April 2004 02:57
To: [log in to unmask]
Subject: [TN] BGA soldering issue


Dear Technetters,

We encountered BGA chip having intermitten contact issue in our prototypes.
When we pressed hard on the BGA chip, the prototype worked ok. We need
advice
on how to tackle this issue from prototype building's point of view. What
measures should be taken to make sure "no contact issue" during prototype
building.

Your advice is very much appreciated. Thanks in advance.

Best regards,
SJ Liew





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