Conductive anodic filamentation (CAF) is a sub-surface electrochemical phenomenon seen in glass-reinforced epoxy laminates when used in the manufacture of printed circuit assemblies. The effect was first reported in the 1970s, but lately there is increasing concern about CAF failure becoming a significant reliability issue, to the extent that CAF could present a major roadblock to feature-size reduction in technology roadmaps.rnPrincipal reasons for this concern are:rn1 The drive to increased circuit density with smaller design geometries and increased layer counts in multi-layer boards;rn2 Rapidly increasing use of electronics in harsh environments and in high reliability and safety critical applications; andrn3 Implementation of lead-free soldering and its effects on laminate stability and properties.
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