Johnathan, 

There is a great body of knowledge about solder joint reliability at both mild thermal cycle and harsh thermal cycle at the JCAA-JGPP report location under NASA TEERM:
http://teerm.nasa.gov/LeadFreeSolderTestingForHighReliability_Proj1.htm

The project 2 results report is at 
http://teerm.nasa.gov/nasa_dodleadfreeelectronics_proj2.htm

I am puzzled why you think you cannot pass 1000 cycles at a delta of 100 degrees C.  In both studies, but lead based and Pb-free solders passed far more cycles than that.   In fact, the Pb-free boards from test 2 are probably still being cycled at Boeing in Seattle.  In harsh cycle, lead-based solders perform best, in mild (100C) cycles, Pb-free solders perform best. 

Denny Fritz








-----Original Message-----
From: jonathan noquil <[log in to unmask]>
To: TechNet <[log in to unmask]>
Sent: Mon, Apr 2, 2012 12:55 pm
Subject: [TN] how to pass solder joint reliability of a 3.2 mm board (16 layers) for QFN packae


Hi All
Need some suggestions on how to handle solderjoint issue (How to tweak to
ass TMCL1000 cycles- 0 to 100C) on QFN packages ( 5 x 6 x 1.0 mm with 8
ins).
inish is Pure Sn
oard is 16 layers 3.2 mm, HASL finish.
Does someone had an experience to share?
thanks

_____________________________________________________________________
his email has been scanned by the Symantec Email Security.cloud service.
or more information please contact helpdesk at x2960 or [log in to unmask] 
_____________________________________________________________________


______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________