Jim, Problem could be in the plating. The appearance of copper would not be suprising if the the supplier had a poor plating process. If you can, cross section a row of solder balls and observe the plating quality. You might find unacceptable variations in the thickness and quality of the gold and nickel plating. Best of Luck, Craig > Good Day Technet: > > First, a little background... We're in production using a 228 ceramic BGA for > a military contract. The base material of the component is gold plated nickel, > prior to solder ball attachment. The gold plating is very thin, around .25 > microns. We've been experiencing approximately 5% (components, that is, not > solder joints) open circuits found at in-circuit testing (ICT). Upon removal > of the BGA (Air-Vac system) from the board, the specific ball location where > the open was identified at ICT shows no solder remaining on the component, > where all other locations has solder remaining. What does remain is a dull, > gray, crystalline metallization. > > SEM/EDX analysis shows Ni/Sn and Cu/Sn. It is presumed that the Ni/Sn is the > intermetallic layer created from the nickel base material and the tin in the > solder. What puzzles me is the presence of the copper-tin crystallites. Since > there is no copper in the solder or on the component, is it possible that this > copper has migrated all the way up from the board pad to the component/solder > interface? > > Thanks in advance... > > ################################################################ > TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c > ################################################################ > To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: > To subscribe: SUBSCRIBE TechNet <your full name> > To unsubscribe: SIGNOFF TechNet > ################################################################ > Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. > For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 > ################################################################ > > Dr. Craig Hillman CALCE Electronic Products and Systems Consortium University of Maryland College Park, MD 20742 (301)-405-5316 [log in to unmask] ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################