11. Lead-Free and Other Process Effects on Conductive Anodic Filamentation Resistance of Glass-Reinforced Epoxy Laminates

Conductive anodic filamentation is a subsurface failure mode in woven glass-reinforced laminate (FR4) materials, where a copper salt filament allows bridging between via walls and other copper conductors. In this study, FR4 laminates, in the form of high-via-density multilayer test circuits, are exposed to different manufacturing conditions and assessed for resistance to conductive anodic filamentation (CAF). CAF performance was assessed using high temperature and humidity conditions to promote failures, with a voltage applied across adjacent via. By the application of a range of voltages and via geometries, a performance map for laminates can be obtained to compare materials for performance. The changes due to exposure of laminate to tin–lead and lead-free temperatures are then examined using the technique.