Dr. Dave: I think that you are one of the industries bright lights, but sometimes you can advance some of the wierdest questions. Dave, at the end of the day, we all want processes that have as wide a window as is possible, but with some processes, it is simply not possible, and with others, it may cost something, either economic, or from a quality point of view, and simply is not worth it. A classic example is the etcher, who would ever try to set up an etch process that could handle any weight of Copper, from 1/4 oz to 3 oz??? Clearly this is a question that must address not only the particular process, but also the variation in materials that it is possible/likely to see. Rudy Sedlak RD Chemical Company ################################################################ 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 ################################################################