Depending on what you are trying achieve with the number of layers you may not be able to provide a breakout pattern as you describe. The breakout , if any , will also depend on your BGA ball arrangement. We successfully route up to 529 pin BGAs on two signal layers, and two planes using 6/6 line and spacing and 50 mil pitch BGAs. Tim Easterling SCI Systems Inc. (205) 882 4426 ################################################################ DesignerCouncil 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 DesignerCouncil <your full name> To unsubscribe: SIGNOFF DesignerCouncil ################################################################ Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ################################################################