There is a very nice study of the effects of reflow time and initial
intermetallic thickness on the attachment reliability of 1206 resistors in
the following paper:
Tu et al., "Effect of intermetallic compounds on the thermal fatigue of
surface mount solder joints", in IEEE-CPMT Trans., Part B, Feb. 1997, Vol.
20, pp. 87-93.

>From the data in the paper, I concluded that (for that particular
device/assembly and for the test conditions that were used: -35/125C) fatigue
life is inversely proportional (to a first order) to the initial
intermetallic thickness (Cu-Sn species).

Jean-Paul
________________________________________________________________
Jean-Paul Clech
EPSI Inc., P. O. Box 1522, Montclair, NJ 07042 - USA
tel: +1 (201)746-3796  fax: + 1 (201)655-0815
Home page: <A HREF="http://members.aol.com/Epsiinc1/index.html">http://members
.aol.com/Epsiinc1/index.html</A>
- click on the above or copy: http://members.aol.com/Epsiinc1/index.html
__________________________________________________________________

***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To subscribe/unsubscribe send a message <to: [log in to unmask]>   *
* with <subject: subscribe/unsubscribe> and no text in the body.          *
***************************************************************************
* If you are having a problem with the IPC TechNet forum please contact   *
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask]      *
***************************************************************************