Mark,

one solution would be buying an ERSAscope. This is an endoscope type of
device that allows you a lateral check of the BGA balls. You can see very
well the outter rows and, by zooming into the tunnel, you can spot the
eventual shorts and opens. Contact ERSA for this. I think Metcal too have
such of device.

The idea of BGA signature is already out, check with Glenbrook Technologies,
they have an article on this. But they propose oval pads. Forget about the
star, I bet Werner is jumping on his chair. The star shape means stress
concentrators that would kill the joints.

Good luck,
Ioan

> -----Original Message-----
> From: Mark Roslawski [SMTP:[log in to unmask]]
> Sent: Wednesday, October 16, 2002 11:45 AM
> To:   [log in to unmask]
> Subject:      [TN] Z-axis BGA solder joint verification ?
>
> Dear TechNetters:
>
> I have a customer that wants to know if there is any way of verifying the
> Z axis solder joint on BGAs ?
>
> He has a x-ray machine that he can see in x and y axis', but he can not
> see in z-axis for good solder joint verification.
>
> He thought about using a star type design pad landing as opposed to a
> circle pad landing so he could see the solder flow into the points of the
> star.  Has anybody done anything like this or does anybody have any
> recommendations ????
>
> Any and all input is appreciated.
>
> Thank You
>
>
> Mark Roslawski
> VP Marketing
>
> ThermalWorks
> 2910 South Oak Street
> Santa Ana, CA. 92707
>
> Tel.  (714) 540-8454 x166
> Fax. (714) 540-1299
>
> Email: [log in to unmask] <mailto:[log in to unmask]>
>
> Web Sites: www.thermalworks.com <http://www.thermalworks.com>
>                    www.SDCcircuits.com <http://www.SDCcircuits.com>
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