Janice,
Although I'm interested in your picture too, I'm more interested in knowing
which ball/package sites fracture (corners?, outer rows?, etc,), what is the
CBGA I/O count, what is package size, and is it a full array or peripheral
array package.
Regards,
George
George M. Wenger, DMTS Bell Laboratories Princeton
Supply Network Solutions
PO Box 900, Princeton NJ 08542-0900
Route 569 Carter Rd., Hopewell, NJ 08525
(609)-639-2769 (Office), 3210 (Lab), 2346 (Fax)
[log in to unmask]
-----Original Message-----
From: Ingemar Hernefjord (EMW)
[mailto:[log in to unmask]]
Sent: Wednesday, May 02, 2001 9:01 AM
To: [log in to unmask]
Subject: Re: [TN] Seeing STARS! (BGA solderball anomaly)
I have seen both stars and stripes, think I know what you mean. I'm
interested in your bre...picture.
Ingemar Hernefjord
Ericsson Microwave Systems
-----Original Message-----
From: Pelchat, Janice [mailto:[log in to unmask]]
Sent: den 2 maj 2001 14:26
To: [log in to unmask]
Subject: [TN] Seeing STARS! (BGA solderball anomaly)
We have some ceramic BGAs that are giving us problems with fractures at the
ball/package interface after reflow.
In the process of failure analysis, we inspected unassembled parts under
high power and have seen two anomalies. One is an apparent shaving of the
outside perimeter balls from what appears to be fixturing at the
manufacturer - that is being F/Ad by the manufacturer. The other anomaly is
what I can only term a "star" shaped appearance on the surface of the
solderballs.
Under very high power, this "star" effect seems (to me at least) to be the
result of the solidification process of the solderball during manufacture.
It looks as though the solder surface separated - then the separations
formed crevices in a star pattern. Think of the appearance of crevices
formed on crusty breads when they bake and cool. (Sorry for the analogy -
in my other life - I bake).
I have a fair picture for those wanting to see a visual. Does this sound
familiar to anyone? Is it part of the normal BGA solderball appearance?
Jan Pelchat
Benchmark Electronics
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