Electronics Forum | Thu Dec 30 21:22:12 EST 1999 | Jim
Mike, Thanks for the reply. It's not really a matter of slope. It is the long term thermomechanical fatigue that the solder joint undergoes as a result of repeated severe temperature swings, while the product is in use. Non-leaded parts are suscep
Electronics Forum | Mon Feb 25 07:59:47 EST 2002 | Jim Mills
Customer has requested a custom CBGA pakaged resistor network.I've seen a lot of info about TCE mismatch but aslo have heard that using 0.025-0.030 balls offers some stress releif which allows for the TCE mismatch to become less of a problem. Would
Electronics Forum | Mon Feb 28 12:52:43 EST 2005 | lyrtech
Sorry, I mismatched my answer, yes they are plated.... Sorry another time...
Electronics Forum | Mon Dec 05 17:03:15 EST 2005 | russ
Ina ddition to the above it can be from CTE mismatch and the joints are breaking during cooling. Is this an Altera part?
Electronics Forum | Fri Mar 19 12:22:36 EDT 2010 | stepheniii
Could it be a CTE mismatch issue?
Electronics Forum | Tue Jun 25 01:24:25 EDT 2019 | sssamw
That is possibley CTE mismatch between QFN and PCB material, the thicker PCB the higher fail rate.
Electronics Forum | Wed Aug 03 21:20:09 EDT 2005 | Ken
CTE mismatch. X, Y, Z all expand at different rates. Cooling or heating rates will not change this CTE mismatch. Layer counts, power plane ballance, equal run lengths in x-y and copper balance all contribute. Have your supplier evaluate your s
Electronics Forum | Sun May 24 21:12:59 EDT 2009 | keith78
I have a problem recently to qualify QFN package on solder joint reliability. The pcb thickness stated in IPC-9701 is 2.35mm but from the in-house test, QFN surface mount on 2.35mm thickness PCB board have a short cycle to failure due to higher CTE m
Electronics Forum | Wed Aug 23 15:10:24 EDT 2000 | Dr. Ning-Cheng Lee
Fillet lifting is a phenomenon mostly observed at wave soldering. It is caused by mismatch in thermal expansion coefficient (TCE) between solder and parts, and aggravated by the pasty range of solder alloys. Upon cooling, the mismatch in TCE will cau
Electronics Forum | Sat Mar 01 08:17:40 EST 2003 | davef
You're correct that the FR4 is probably the best choise. The majority of the problems in developing your reflow recipe is going to come from the CTE mismatches in the CCBGA , CBGA and PBGA that you put on the board. The other side says given the pr
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