Dear Mr. Savard, First of all, be assured that my purpose was not to confront you but just to clarify the concept of the pulse periodic reverse technology and its mechanism when applied to electrodeposition of copper onto PCBs. In fact, for other applications, the use of this technique has actually the purpose of 'really stripping' the metal already deposited on the cathode during the reverse cycle and I just wanted to make clear that this is not what is happening in the case that interests us (PCBs). As said in a previous e-mail, the pros and cons of this technology are, now, well known and defined altough I would make an additional comment. There is a real need for improving the existing pulse periodic reverse (PPR) technology and this being worked on. The PPR technique, as most of us know it, is actually a static technique and therefore not fully optimizable for a complex system as an electrolytic cell designed to plate copper onto a complex board containing features as small holes, big holes, blind vias, isolated traces, ground planes areas, etc... The use of a static technique, in that case, is just a step but not a satisfactory answer. We need to evolve to a dynamic technique which would be able to integrate all the pulse characteristics necessary to the optimization of a such system. The Complex Wave Form (CWF) technique has been developed to head into this direction of dynamic technology. Although slightly more complex, the CWF can propose number of advantages as the use of a much lower reverse current density. As I explained it before, the goal is to redistribute the overall polarization on the board in order to compensate for the primary current distribution (geometry of the board). There are several ways to achieve this. Pulse periodic reverse technology, as we described it, is one of them but certainly not the only one. This being said, we are currently working on the optimization of such dynamic technique in order to provide PCB manufacturers with answers on how to answer their customers requirement on increasing complex board designs without sacrifying their productivity and producing better quality products. Best Regards, Stephan Menard Electrochemist - Chemical Engineer Micropulse Plating Concepts ############################################################## TechNet Mail List 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://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################