mike just out of curiosity - try taking section and see if the nodules rise from the surface of the copper topography - u'll have to make a makeshift sorta 3-d thing - slant it somehow when looking. if it does - try doing a trace metal analysis with an AA for tin in solution. if your above 20ppm - u might be co-depositing tin with in your copper. if that;s the cas - try dummying at about 3-5 asf for about 8 hrs and do another tin analysis. regards Richard Fudalewski Florida CirTech ############################################################## 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 ##############################################################