XPS/Auger will do the trick... you can get composition (and plus IR scan in the same region) to (hopefully) pin point the source of defect (you have to know enough about the chemistry and process of the Au in order to do the FA...The problem is, most of FAB don't even know the detail chemistry and process)... my 1.35 cents...jk -----Original Message----- From: Mike Di Giacomo [mailto:[log in to unmask]] Sent: July 12, 2001 7:12 PM To: [log in to unmask] Subject: Re: [TN] Staining on Gold Hi Bev, If you want to determine the composition of the stain, I've found doing an SEM/EDXA (Scanning Electron Microscope /X-Ray Diffraction) of the stain and background should tell all you need to know. In my past life we had discoloration on gold pads that were to have die attach/wire bonding done to it and in that case we had some problems, soldering to SMT pads wasn't an issue. Hope this helps, Mike Di Giacomo Process Development Engineer WorldHeart Corp. -----Original Message----- From: Bev Christian [mailto:[log in to unmask]] Sent: Thursday, July 12, 2001 6:37 PM To: [log in to unmask] Subject: [TN] Staining on Gold TechNetters, I have checked the archives and have not been successful in finding sufficient info on the titled subject. Either I have not done a diligent enough search or the info is not there. So, here are my questions. 1) If you were presented with varying amounts of what looks like water stains on immersion gold pads how would you determine its composition? No guesses now, I can do that. I want to know how people have actually done it! Also, I am not referring to "purple plague" but just slightly off color gold. 2) Has anyone ever been able to correlate amount of staining to solderability issues? Or is it a non-issue? 3) Has anyone seen staining cause problems with respect to keypad electrical continuity? regards, Bev Christian Research in Motion ------------------------------------------------------------------------ ---- ----- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ------------------------------------------------------------------------ ---- ----- ------------------------------------------------------------------------ --------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ------------------------------------------------------------------------ ---------