Electronics Forum: cte mismatch (Page 2 of 6)

Is IPC-9701 apply to QFN package?

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 | Mon Aug 21 19:35:51 EDT 2000 | Dave F

Kyung Sam Park: Sure, several causes of plastic QFP package delamination, other than humidity absorption, are: * Corrosion on component leads * CTE mismatch between leads and package materials * Package material adhesion strength degradation Wh

Micro crack for lead free wave solder

Electronics Forum | Wed Aug 03 21:29:59 EDT 2005 | Ken

Yes, lead can promote fillet lift. In order to understand this defect you must begin looking at your lead frame mateials. some lead frames are more susceptable to this disorder. This is most likely a cte mismatch disorder. Lead contamination in

Fillet Tearing

Electronics Forum | Wed Mar 22 21:27:45 EST 2006 | KEN

Find out the lead frame alloy. Cte mismatch can cause the same defect. Ran into this 3 years ago wave soldering with Tin-Copper.....okay, you caught me. I admit it. Wavemaster larry told me about this and I'm posting it under my name. Shameful, I

detecting BGA micro cracks

Electronics Forum | Thu Feb 11 08:14:41 EST 2010 | scottp

It's OK to have the daisychain done in the interposer rather than the die (and a lot cheaper) but in thermal cycling the parts MUST have representative die. That's where a large part of the CTE mismatch comes from to cause fatigue damage. Thermal c

Poor Solderability on TSOPs with Alloy 42 Leadframes

Electronics Forum | Wed Jun 29 17:38:16 EDT 2005 | GS

Several years ago, we had almost same pbm, best results have been obtained by using water soluble paste (those time the old AM1208). Any way, to get a good toe meniscus is not so easy. Talking about CTE, keep in consideration the internal die of TSO


Electronics Forum | Thu May 26 21:07:22 EDT 2005 | KEN

This is caused by cte mis-match. The balls in the corners are short and fat. The balls near the null point are tall and more normalized. I don't remember what the zone settings were... BTU VIP98 BS was probably 22-25 IPM

Recommended TG material for CCBGA , CBGA and PBGA's

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

Conformal Coating BGA's

Electronics Forum | Wed Jan 12 13:27:42 EST 2005 | carobin

The two options I see are (not including underfill): 1) Have complete conformal coating coverage of all balls with no webbing in between balls because of CTE mismatches. If all the balls are not coated we see failure in humidity testing. or 2) Sea

BGA ball Separation

Electronics Forum | Tue Jul 25 12:14:39 EDT 2006 | russ

All my studies led me to believe that it was CTE mismatch of this package. Altera was of less than 0 help in this matter. The other possibility was an ICT test fixture. Unfortunately (?) the design life of this product was at end and the new design

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