Greg, Besides what Doug said, It all depends... If you have silicon on silicon you can do a bang-up job with the unfilled flux underfills. If you are going Si to laminate, you best plan on using a filled material. Even if you have to go with a post-applied capillary underfill. Regarding repairability. They say they are, but ... rework can be a real &$@% Better to assume you have a non-repairable assembly and do your homework up front, if you can - or just bit the bullet and go to a post-applied underfill after test and rework. My parting shot for the day Steve Creswick Sr Associate - Balanced Enterprise Solutions http://www.linkedin.com/in/stevencreswick 616 834 1883 -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Greg Munie Sent: Friday, March 07, 2014 2:55 PM To: [log in to unmask] Subject: [TN] Fluxing Underfills Anyone have any experience with fluxing underfills? How well do they work on larger bumped packages? Are they repairable? The question came up here at IPC but I've been out of the flux business too long to answer. Greg Munie Ph.D. Director of Design Programs +1-847-616-7100 tel +1-847-597-2803 direct [log in to unmask]<mailto:[log in to unmask]> www.ipc.org<http://www.ipc.org/> [cid:[log in to unmask]][http://www.ipc.org/images/shim.gif]<htt p://www.ipc.org/> ______________________________________________________________________ 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] ______________________________________________________________________