MANUFACTURE OF WIRING BOARD

PURPOSE:To bury a through hole flatly and to improve mechanical strength by hindering the accumulation of a filler from the sidewall of the through hole and by accumulating the filler from the bottom face alone of the through hole. CONSTITUTION:A through hole 5 passing through a resin layer 3, in which hole a wiring 2 appears at the bottom face, is opened and a conductive filler 7 is accumulated to fill up the through hole 5 and to connect electrically with the wiring 2. Before this filler 7 is accumulated, a metal layer 4b is deposited to cover the inner surface of the through hole 5 and the surface of the resin layer 3. Also, an insulating layer 4c having an opening 5a, in which the metal layer 4b is exposed, in the bottom face of the through hole 5 is formed to cover the face of the metal layer 4b other than the region of the opening 5a. Then, a conductive material having the metal layer 4b as one electrode is plated so that the through hole 5 is buried in and the filler 7 is accumulated on the metal layer 4b exposed on the bottom face of the through hole 5. When the insulating layer is formed on the metal layer covering the sidewall of the through hole, the filler is prevented from accumulating from the sidewall of the through hole.