subject: pretreatment of innerlayers to improve yields in innerlayers production, we are considering the use of chemical cleanning instead of pumicebrush prior to lamination of photoresist. there is a new trend towards using chemical cleaning only to remove passivation (e.g. chromate) and impurities like organics, oxides etc. this should be achieved by a hot alkaline spray cleaner followed by a ordinary acidic spray cleaner. we are using FR4-copperclad, thickness 0,10 to 0,70 mm, copperfoil; 12 to 70 µm. the thickness of the passivationlayer is 7,0 nm (0,007 µm). If you have had used/or are using this new principle of pretreatment of innerlayers, we would like to hear what was/ is your experience with the process. best regards peer fisker *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************