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Date: | Thu, 31 Jan 2008 13:59:01 EST |
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Hi Tom,
You got me utterly confused.
I understand you have opens
HOWEVER,
are the opens related to the underfill?—then they have to be fractured
SJs; just because you verified the 'underfill profiles' does not mean that the
underfill is doing what you are expecting [see my reliability column in the
March 2006 issue of GSMT&P].
are the fractures of the vias?—then it is the PCB and has nothing to do
with the underfill. Are you SAC-soldering? Then likely your PCB design is
inadequate for the high soldering temperatures [see my White Paper on the proper
specification of PCBs for lead-free soldering and my columns in the Sept. 2006
and January 2007 issues of GSMT&P].
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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