Hi Richard, Interfacial separation can be caused by a number of things. First of all, you must identify if the separation is occurring between the electroless copper and the post or the electroplated copper and the electroless copper. In case one, some possible causes could be: 1. If the rinse following your cleaner on the electroless line is not adequate, you can carry surfactants into your micro-etch creating a micro-polish. The polished surface of the interlayer post can not offer the mechanical interlock of a micr-etched post. When thermal cycling a PCB, depending on the cure level of the laminate, you will introduce Z-axis expansion. In the case of under-cured "green" laminate, Z-axis expansion can be excessive. Thus, introducing increased stress on the interfacial bond. 2. If the aspect ratio is high for the holes that are experiencing interfacial separation, there may not be adequate turbulence in the process baths for the chemicals/rinses to do their jobs. Make sure there is good mechanical agitation and the rinses are arranged to create a vortex flow in the tank. If you are employing counter-flow rinses, from my experience, the industry standard for flow is 2-3 gallons per minute. 3. Depending on the mechanism used for electroless copper bonding, the "catalyst" for the system may not be performing properly. Check chemical concentrations and bath lifes. In case 2: 1. From my experience, the main cause for post separation where electrolytic copper separates from the electroless is high organic levels in the acid copper bath. Check for total organic content. Contact your chemical vendor for recommended organic levels. From memory, I believe anything above 1000 ppm can cause problems. If this is the case, organics can easily be removed by "carbon treating". There are other possibilities, but I think I covered the main ones. I hope this helps, Joel Fillion Process Engineer Matsushita Electronic Materials At 10:43 AM 5/12/98 -0400, Richard W. Boerdner wrote: >howdy folks! > >can anyone explain the possible causes in a manufacturing process that >would result in interfacial separation after thermal stressing of a PCB? >the temperature profile parameters are -40 C to +55 C with a 6 degree >per minute rate of rise and an hour dwell time at each extreme for a >period of 12 hours. the laminate has a glass transition temperature >rating of 170-180. > >################################################################ >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 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 >################################################################ > > > ################################################################ 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 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 ################################################################ ################################################################ 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 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 ################################################################