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Reply To: | TechNet E-Mail Forum. |
Date: | Mon, 11 Aug 2003 12:56:38 EDT |
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Hi All,
While it has been evident from the results published by various sources, that
LF-solders creep slower than Sn/Pb solders, I did not realize that the creep
rates can be as much as 100 times slower. You may want to look at a paper by
Günter Grossmann et. al. at <
www.weichloeten.de/eureka-leadfree/04gg-comp-rel.pdf>. The consequence of this is, that the results of accelerated temperature
cycling tests with short or no dwells at the cyclic temperature extremes are
meaningless in comparing the reliability of LF-solder joints to Sn/Pb-solder
joints. Thus, the claims that one sees about the equivalent or superior
reliability of LF-solders cannot be drawn from any of the test results I have seen so
far.
While LF-solders are o.k. for consumer goods such as cell phones, I would
urge caution in using them for high-reliabillity applications.
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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