David, I did extensive testing of ISR with a customer trying to increase these values. When SEM/EDX was done on test coupons which passed SIR with flying colors vs. those failing SIR a cohesive pattern of chrome and other metals was found on the laminate surface of those which failed SIR testing. This indicated that the chromate conversion coating on the copper cladding had embedded in the laminate and was not removed by alkaline etchant. Product which passed SIR had this pattern of chrome broken up sufficiently. SIR testing measures surface conductivity and detected this metallic pattern. Chrome would not be detected by ionic testing because this test removes conductive material from the surface, then measures the conductivity of the solution. If you want to discuss this more, call me. You have my card. Dave Sullivan [log in to unmask] *************************************************************************** * 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. * ***************************************************************************