WIRING BOARD AND MANUFACTURING METHOD THEREOF

PROBLEM TO BE SOLVED: To provide a wiring board on which high-performance electronic components can be mounted without using a silicon interposer.SOLUTION: The wiring board comprises a base wiring board 2 and a re-wiring part 3. The base wiring board 2 includes: a wiring layer 21; an insulating layer 31 in which the wiring layer 21 is embedded and a via hole VH1 is formed at a lower side of the wiring layer 21; and a wiring layer 22 which is formed at a lower side of the insulating layer 31 and connected to the wiring layer 21 via a via conductor within the via hole VH1. The re-wiring part 3 includes: an insulating layer 34 which is formed on the base wiring board 2 and with which a via hole VH4 is formed on the wiring layer 21; and a re-wiring layer 41 which is formed on the insulating layer 34 and connected to the wiring layer 21 via a via conductor within the via hole VH4. The re-wiring layer 41 is formed from a seed layer 41a and a metal plating layer 41b thereon, and the seed layer 41a is as wide as or wider than the metal plating layer 41b.