| 摘要 |
PROBLEM TO BE SOLVED: To provide a wiring board excellent in reliability of electrical insulation between a core wiring conductor and a built-up wiring conductor.SOLUTION: A dummy built-up insulating layer D5 is laminated on the upper surface of a core substrate 1 having a recess in the central part of the upper surface. A dummy built-up insulating layer D6 connected with a core wiring conductor 3 of the outermost layer on the upper surface of the core substrate 1 is disposed on the dummy built-up insulating layer D5, so that only the interconnected conductors, out of the dummy built-up insulating layer D6 and core wiring conductor 3, are superposed, and a built-up insulating layer 5 and a built-up wiring conductor 6 are laminated thereon. |
