Ultrasonic clean will damage the wire bond in some cases.
                          jk

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Blair K. Hogg
Sent: Wednesday, August 03, 2005 1:27 PM
To: [log in to unmask]
Subject: Re: [TN] Question on cleaning boards with BGA.


Hot cracked solder joints, but I have seen US cleaning damage components.
Back in the late 80's a component manufacturer that my employer at that time
was using was manufacturing a component with preformed leads soldered on a
ceramic (thick film, I presume) substrate. The device was US cleaned after
the leads were soldered. The US cleaning caused fractures in the leads where
they were formed at the component end. Eliminating US cleaning corrected the
problem.

Not sure if US in use today would have the same affect.

Blair

>>> [log in to unmask] 08/03/05 08:34AM >>>
I have never heard of US cleaning causing cracked solder joints. I have
used US for thousands of assemblies with BGAs, flipchips and uBGA and
CSP components, and have never had any such thing happen. Perhaps I was
lucky. Do you have any documentation to support that general statement?



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