| 摘要 |
PROBLEM TO BE SOLVED: To provide the interlayer connection structure of a wiring board for easily achieving a fine pattern without excessively thickening a middle conductive layer, a manufacturing method for preventing a large cavity from being generated in the filter of a hole in a lower layer without any stoppers, and a punching device for the manufacturing method. SOLUTION: An upper-layer insulating layer 14 is machined by the laser beam in a ring mode, and a closed-end hole 17 is formed directly above a through hole 16. Even if the lid plating (the stopper of laser machining) of the through hole 16 is not formed, a resin 12 forms nearly a flat surface at the bottom of the closed-end hole 17, thus preventing the middle conductor layer (a level marked by an arrow B) from being set to thickness exceeding required thickness in the interlayer connection structure of three layers where the closed-end hole 17 is stacked directly above the through hole 16. |
