Hello Bev - see my comments below: Dave Hillman Rockwell Collins [log in to unmask] Bev Christian <[log in to unmask] OM> To Sent by: TechNet [log in to unmask] <[log in to unmask]> cc Subject 12/14/2006 12:50 [TN] Qualifying reworkable PM underfills Please respond to TechNet E-Mail Forum <[log in to unmask]> ; Please respond to Bev Christian <[log in to unmask] OM> Technetters, Back after almost a year off-line. *** Welcome back It has always been my philosophy to thoroughly test ANY chemical that is going to come in contact with a PCB or PCBA - tapes, labels, inks, markers, adhesives, cleaners, temp solder masks, permanent solder masks, flux stops, lubricants for compression fit pins, solder wicks, dusters, freezing agents, OSPs, cored wires, fluxes, thinners, tacky fluxes, paste fluxes, solder pastes, underfills, conformal coatings and thermal compounds. *** Good philosophy and are you sure that your list is complete? : -) Lab testing includes copper mirror, halide ion, SIR and electrochemical migration. It sometimes includes other tests, but let's leave it at this for the moment. *** Wait a second - you didn't mention Ion Chromatography! You are going to make Mr. Pauls feel left out. Here's my problem: I have tested many reworkable underfills from all the people you can think of and I CAN'T FIND A SINGLE ONE THAT WILL PASS BOTH IPC SIR AND ECM TESTING. These materials were tested at the same time that we had control coupons in the chamber (passed), solder pastes (passed) and normal underfills (passed), so I doubt it was the chambers (more than one) or that there were water droplets (checked, none evident). *** Ok , here is the only serious comment of the reply. Something doesn't make sense. The underfill materials surely meet the IPC SIR/ECM requirements in a standard material test otherwise the suppliers would not market the underfill materials. So, my guess would be that possible root cause for your reworkable underfill failures would either be improper curing of the material (uncured underfill will not pass SIR/ECM) or there is a reworkable underfill/solderpaste flux incompatibility issue. Those are the two items I would chase. Have you conducted IC testing on the SIR/ECM coupons to see what extractable species are present? My customers are pushing me to allow them to use the stuff and I am resisting. Comments, please. *** You have three options: -Resistance is futile, you will be assimilated..... -Walk away from the light............ -Have the Technet crew give you suggestions Bev Christian RIM --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------