A wiring board in the present invention includes an insulating layer, a via-hole penetrating from an upper surface to a lower surface of the insulating layer, a wiring formation layer, and a grounding or power supply conductor, in which the wiring formation layer is formed of a plurality of strip-shaped conductors, and an insulating resin portion filled in at least between the strip-shaped conductors, the grounding or power supply conductor is formed to partially face the strip-shaped conductors, and a relative permittivity of the insulating layer is higher than a relative permittivity of the insulating resin portion.
1. A wiring board comprising:
an insulating layer having a relative permittivity of 4.5 or more;
a via-hole penetrating from an upper surface to a lower surface of the insulating layer to electrically connect the upper surface to the lower surface of the insulating layer;
a wiring formation layer formed on a surface of the insulating layer; and
a grounding or power supply conductor formed on a surface opposite to the surface of the insulating layer on which the wiring formation layer is formed, wherein
the wiring formation layer is formed of a plurality of strip-shaped conductors extending in parallel to each other, and an insulating resin portions filled in at least between the strip-shaped conductors,
the grounding or power supply conductor is formed to partially face the strip-shaped conductors, and
a ratio of the relative permittivity of the insulating layer and a relative permittivity of the insulating resin portion is at least 1.125.
2. The wiring board according to claim 1 , wherein
each of the strip-shaped conductors has a triangular cross-sectional surface taken vertically in an extending direction.
3. The wiring board according to claim 1 , wherein
a difference between the relative permittivity of the insulating layer and the relative permittivity of the insulating resin portion is 0.5 or more.
4. The wiring board according to claim 1 , wherein
the insulating resin portion has the relative permittivity of 2 to 4.