Hydrophobic Silane Coating for Preventing Conductive Anodic Filament (CAF) Growth in Printed Circuit Boards

摘要

An enhanced substrate for making a printed circuit board (PCB) includes a hydrophobic silane coating of a silane composition intermixed with a silane coupling agent applied to a glass fiber substrate. The silane coupling agent is applied to the surface of the substrate for coupling the substrate to a varnish coating. Applying the silane coupling agent to the surface of the substrate creates surface silanols, which are implicated in conductive anodic filament (CAF) growth. A silane composition, which reacts with the surface silanols, is applied to the surface of the substrate having the silane coupling agent applied thereto to form the hydrophobic silane coating. The surface presented by the hydrophobic silane coating/substrate is hydrophobic and essentially silanol-free. This surface is then dried, and varnish is applied thereto. Then, the substrate, hydrophobic silane coating and varnish are subjected to curing conditions to define the PCB.