Has anyone built a 4 layer mulitlayer PCB utilizing Rogers RO4003/4350 materials for two layers and FR4 for the other 2 Questions : what type of stack up did you use we are imagining 0.020 RO double side material FR4 prepreg and 0.020 FR4 double side for a finished of aprox 0.062 What happens to flammability rating if you hybrid 94VO rated FR4 with non rated RO4003 Can we still expect UL approval if we utilize FR4 and RO4350 which is 94VO rated Also what sort of cost saving is to be expected by utilizing FR4 for the non critical layers. *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * ***************************************************************************