HI Vlad - we can't open Dropbox here due to firewall restrictions so can you have Steve G. post the pictures? Dave Hillman Rockwell Collins [log in to unmask] On Wed, Dec 9, 2015 at 4:59 PM, Vladimir Igoshev <[log in to unmask] > wrote: > HI everyone, > > I'm attaching a link to a file showing something I'd appreciate your > thoughts on. It's a cross-section of a QFN on an IAg board; > Pb-free/no-clean process. As you can see from the EDS spectrum, that > greyish stuff between pins has pretty much only Sn and O in its elemental > composition. > > I know there is burn flux residue around solder joints but that stuff > doesn't have any C in it. The question I have is what is it. > > I spoke to Bev and both of us are still puzzled. > > Here is the link: > https://www.dropbox.com/s/3wbj62vqjyhvj2y/What%20else%20it%20can%20be.pdf?dl=0 > > Thank you very much in advance. > > Regards, > > Vladimir > > SENTEC > > > ______________________________________________________________________ > 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] > ______________________________________________________________________ > ______________________________________________________________________ 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] ______________________________________________________________________