Wiring Board Surface Roughness Control for Insulation Reliability

The patent applies local quality by creating different roughness levels in different regions of the insulation layer surface. Specifically, the surface under conductive portions has higher roughness (first roughness) to enhance adhesion, while the surface between conductive portions has lower roughness (second roughness) to prevent short circuits. This spatial variation in surface properties resolves the contradiction between needing high adhesion and maintaining insulation reliability.

The patent applies local quality by creating regions with different catalyst concentrations on the insulation layer surface. The surface under conductive portions has higher catalyst concentration to ensure uniform electroless plating, while the surface between conductive portions has lower or no catalyst to prevent unwanted plating and reduce overall catalyst consumption. This spatial variation in catalyst distribution resolves the contradiction between achieving plating uniformity and reducing catalyst quantity.

The patent applies local quality by differentiating surface roughness in different regions. The surface under conductive portions maintains higher roughness for good adhesion, while the side surfaces of conductive portions have controlled roughness to ensure smooth profiles that facilitate soldering. This regional differentiation allows the process to achieve both manufacturing simplicity and good solderability by treating different areas with appropriate roughness levels.