| abstract |
A wiring board capable of realizing a high density wiring layer is provided. The wiring board is formed to cover a core layer, a first wiring layer formed on one surface of the core layer, and the first wiring layer on one surface of the core layer. The first insulating layer, the via wiring embedded in the first insulating layer, and the second wiring formed on the first surface which is the surface opposite to the surface in contact with the core layer of the first insulating layer A first insulating layer, and a second insulating layer formed on the first surface of the first insulating layer so as to cover the second wiring layer and being thinner than the first insulating layer. The layer includes a pad and a plane layer provided around the pad, the first surface of the first insulating layer is a polished surface, and one end surface of the via wiring is the first surface The first insulating layer is exposed from the first surface and directly joined to the second wiring layer, and the other end surface of the via wiring is connected to the first insulating layer. In is joined the pad directly. [Selection] Figure 1 |