Another try.

I am resending this, because when I opened what I got from Technet it was
pretty garbled.

Nee how Chris,
What you describe is very unusual.
Normally, the smaller the hole diameter, the earlier the barrel crack.
Reason: it is more difficult to plate good copper into smaller-diameter holes.
If you only measure at the beginning of the test and at the end at room
temperature, the fracture surfaces will make good contact under compression, and it
is like matting connector surfaces. The reason for this is that during the
high temperature the barrel is stretched and somewhat plastically deformed. Then
fatigue failure happens. On cooling the resin shrinks backk to its original
volume, and the fractured halves of the stretched barrel are pressed together.
That is why one should always measure the daisy-chain resistance during
testing; that way, you also know when the failures occurred.
How do you know " All have complet barrel crack except the holes of 10mils
."?



Regards,
Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL 32174 USA
Phone: 386-437-8747, Fax: 386-437-8737, Cell: 386-316-5904
E-mail: [log in to unmask], Website: www.engelmaier.com

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