Vladamir,

They are filled, but not copper filled

Franklin

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Igoshev, Vladimir
Sent: Tuesday, March 18, 2008 10:01 PM
To: [log in to unmask]
Subject: Re: [TN] How much stress is needed?

That is what I initially thought, but didn't Franklin mean Cu filled via???

Vladimir

----- Original Message -----
From: TechNet <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Sent: Tue Mar 18 22:44:41 2008
Subject: Re: [TN] How much stress is needed?

Hi Franklin,
You describe a classic via barrel crack—comes from the thermal expansion 
mismatch between the ED copper and the PCB resin in the z-direction during the 
soldering processes [the hotter the worse—read lead-free] [you should be taking 
my workshop on the subject at IPC EXPO/APEX on the morniong of March 31.

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, Cell: 386-316-5904
E-mail: [log in to unmask], Website: www.engelmaier.com



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