Do not know if passing, or failing, the Bellcore ionic contamination test (for innerlayers) will affect this kind of problem, but suspect that a board that passes, will be less likely to fail, given that the ionic contamination can provide some sort of reduced resistance which can lead to electron leakage, which can lead to electromigration....? And, this test is a bear, as certain laminates seem to pick up, and hold, metal ions (Copper) from the processing solutions (etch, microetch, etc). We have had some success in passing getting boards past this test by cleaning them with HEAVILY chelated alkaline cleaners. This seems to suck the Copper out of the substrate. ( My old chemistry prof would be spinning in his grave if he heard me discuss chelation in those terms, but it actually fits real well...) This is an FYI. Rudy Sedlak RD Chemical Company [log in to unmask] ############################################################## TechNet Mail List 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 web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################