Wiring Board Laminate Seed Layer for Fine Copper Circuit Linearity

The patent applies preliminary action by forming a seed layer on the insulating substrate before copper plating. This seed layer serves as a foundation that enables subsequent copper deposition to achieve finer wiring patterns. The seed layer is prepared in advance through specific surface treatment and copper formation processes, allowing the final copper wiring to reach the required fineness that would not be possible with direct plating alone.

The patent applies local quality by creating protrusions only in specific regions where adhesion is needed, rather than uniformly roughening the entire resin surface. The protrusions are formed locally through controlled copper deposition and etching processes, concentrating the adhesion-enhancing features only where required for bonding strength, while leaving other areas smooth to minimize signal transmission loss and maintain circuit linearity.

The patent applies segmentation by dividing the copper formation process into multiple stages: first forming a thin seed layer, then selectively plating copper only in required wiring areas. This segmented approach replaces the need for a single thick copper deposition step, enabling fine wiring precision while maintaining manufacturing feasibility through controlled, incremental copper formation.

The patent introduces an intermediary approach by using a seed layer as a mediating structure between the resin substrate and the final copper wiring. The seed layer provides the necessary adhesion interface through controlled protrusion formation, while the subsequent copper plating builds upon this foundation to create the final wiring structure with minimal protrusions, thus maintaining both adhesion strength and low transmission loss.