WIRING BOARD, MANUFACTURING METHOD THEREFOR AND ELECTRIC CIRCUIT ASSEMBLY

摘要

PROBLEM TO BE SOLVED: To provide a wiring board having high density of conductive vias and high wiring density. SOLUTION: The wiring board has a base board 1, a wiring layer laid on at least either the front or the back main planes of the base board 1, and an insulation layer laid thereon. The base board 1 has a plurality of openings 9, piercing the thickness of the base board 1 and one or more conductive vias 3 disposed in the openings 9. Two more conductive vias 3 are disposed in at least one of the openings 9.