I've had similar experiences as Dave.  CSAM was able to detect some voiding in
joints, etc., but not much more than X-ray.  We were able to see some
delamination in the joints, but it was kind of hit or miss.  I'd say that there
is promise in the technique, but it needs development.
Rod Martens
Hewlett-Packard.
[log in to unmask]

-----Original Message-----
From: Non-HP-ddhillma
/hp-ftcollins,[log in to unmask]
Sent: Tuesday, September 29, 1998 8:00 AM
To: Non-HP-TechNet /hp-ftcollins,[log in to unmask]
Cc: Non-HP-ddhillma
/hp-ftcollins,[log in to unmask]
Subject: Re: [TN] ASSY: BGA FAILURES

Hi Jim - The good news is yes (and as proof that everything has been tried
by someone, at sometime and that there is someone on TechNet that knows
that somebody) -  I have tried to use ultrasonic inspection techniques for
the inspection of BGA packages.  The bad news unfortunately is that I was
unsuccessful - due to the number of material types, and material interfaces
I could not distinguish the solder joint-to-pwb interface with enough
resolution to see solder joint cracks, voids, or opens. The anomalies I was
able to detect using ultrasonics I was also able to detect with xray
inspection techniques. The folks at SonoScan may be able to help but my
trials led me to the conclusion that ultrasonic techniques would not result
in the inspection data I wanted. Good Luck.

Dave Hillman
Rockwell Collins
[log in to unmask]




Jim Marsico 516-595-5879 <[log in to unmask]> on 09/29/98 06:48:00 AM

Please respond to "TechNet E-Mail Forum." <[log in to unmask]>; Please respond
      to Jim Marsico 516-595-5879 <[log in to unmask]>

To:   [log in to unmask]
cc:
Subject:  Re: [TN] ASSY: BGA FAILURES




Well, how about it!  Does anyone have any experience using ultrasound to
detect
cracked solder joints?  Does anyone know of a testing lab that can perform
this
function?

Thanks again...

Jim Marsico


Mark wrote:

Dear Jim

This may be a very stupid idea, but what about using ultrasound?

I believe they use ultrasound to detect microscopic fractures in mechanical
assembly's and the joint between the CBGA and the solder ball is
mechanical.

I don't know what the ultrasound would do to the chip or the wire bonds but
it may be worth some more inquiries to the component manf.

I would be very interested to read how you got on.

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