Clarissa It depends upon when you can check for smear. If you are lucky enough to do it after desmear and prior to other metallization steps, you can send the sample through your oxide line. The copper inner layers at the the barrel will turn black because they will be coated with oxide - the copper areas with a fine coat of smear will remain copper colored because the oxide won't stick to the copper under the smear If you have to inspect after all processes - then microsection as received will tell you if you have smear There are a few of us who believe if you can see a line where the inner layer connection should be prior to microetch it is a very large probability that you have smear instead of separation. (Of course it is separation no matter whether smear or separation) Susan Mansilla 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 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 ################################################################