Broken glass fibers caused by poor tooling parameters is my first thought.
The loss of fibers leaves a small cavity that will be filled by Copper,
sometimes even by solder. I assume, that the preparation is correctly done,
so we can exclude smear.

I think you can sleep tonight, this failure can be easily fixed with a fresh
diamond tool in your Excellon. 

If you use laser drilling, the above is not valid.

Inge


-----Ursprungligt meddelande-----
Från: TechNet [mailto:[log in to unmask]] För Jack Olson
Skickat: den 1 oktober 2007 18:56
Till: [log in to unmask]
Ämne: [TN] Is This a BAD Thing?

I'm not accustomed to looking at reliability issues,
(my designs are usually so perfect... (grin))
so every time I see an X-Ray or a cross-section
I get nervous wondering what I'm actually seeing.

Can anyone explain what the following picture means?

http://www.frontdoor.biz/PCBportal/208what.jpg

onward thru the fog,
Jack

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