Hi Mumtaz,
These assemblies have both a lot of thermal mass as well as a lot of physical mass. 
Those cracks come from either PCB warping because of thermal gradients/expansion mismatch or mechanical PCB bending.
Werner

 


 

 

-----Original Message-----
From: Mumtaz Bora <[log in to unmask]>
To: [log in to unmask]
Sent: Sun, Dec 5, 2010 2:00 am
Subject: [TN] QFN package crack post Reflow


 

Hello Technetters,

 

Received a customer return showing QFN package cracking after double

sided reflow on a board with coax connectors near the package.  Board

shows a lot of thermal mass on one side. Do not have the details of

solder material and reflow  profile. I have posted a .PDF file of images

on the following link. Please go to the file tab , not photos. Your

comments/feedback will be appreciated. 

 

 

http://ipc-technet.groupsite.com/main/summary

<http://ipc-technet.groupsite.com/main/summary> 

 

 

 

Thank-you, Mumtaz

 



Mumtaz Bora



Senior Packaging Engineer



Peregrine Semiconductor



9380 Carroll Park Drive



San Diego, CA 92121



858-795-0112-direct



858-731-9499 -fax



[log in to unmask]



 



 



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