| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for forming a uniform plating film, in a method for electrically connecting upper and lower conductor circuits via a small diameter blind via hole, having a large aspect ratio by a metal plating film. SOLUTION: A printed circuit board comprises an upper conductor circuit 521 on an upper surface of an insulation layer 619, a lower conductor circuit 622 on a lower surface of the layer 619, a blind via hole 615 having the conductor circuit 622 as a bottom and provided between the upper circuit 621 and the lower circuit 622, and a metal plated layer provided on an inner wall of the via hole 615 for electrically connecting the upper and lower conductor circuits. The circuit board further comprises a plating liquid flowing hole 632, having a diameter smaller than that of the via hole 615 and is provided at the lower circuit 622 for constituting the bottom of the via hole 615, prior to plating. |
