Patent ID: 8629550

Claim:
A printed wiring board comprising: a substrate comprising a substrate surface; and a wiring pattern formed on the substrate surface and comprising: a first wiring line comprising a first line electroless copper plating layer formed on the substrate surface, and a first line electrolytic copper plating layer formed directly on the electroless plating layer such that the first wiring line has a top surface and a first side wall face which extends from the substrate surface to the top surface of the first wiring line, a second wiring line comprising a second line electroless copper plating layer formed on the substrate surface, and a second line electrolytic copper plating layer formed directly on the electroless plating layer such that the second wiring line has a top surface and a second side wall face which extends from the substrate surface to the top surface of the second wiring line, the second wiring line intersecting the first wiring line at an angle to form a crossing portion where the first and second side wall faces of the wiring pattern cross at an angle, and a fillet added to said corner portion of said wiring pattern when the wiring pattern is formed, said fillet including a fillet wall face extending vertically from the substrate surface to respective top surfaces of the first and second wiring lines and connecting the first side wall face to the second side wall face, the fillet wall face being concavely curved toward said corner portion and having a predetermined radius such that the fillet wall face provides a transition from the first side wall face to the second side wall face.