There are a couple of questions before we can try to give advise. Do you have a crack in the inner layer foil itself? If so you should 1. check amount of etchback - too much unsupported copper foil can crack. 2. check z-axis expansion 3. check the type of foil in the board - high temp elongation or ? Do you have separation between the inner layer and the hole wall plating? If so you should 1. determine where the separation occurs - electroless/foil, electroless/ electrolytic or within the electroless 2. then you can start addressing the various processes which could be responsible Susan Mansilla Technical Director Robisan Lab ################################################################ 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 ################################################################