Multi-layer wiring substrate

A multi-layer wiring substrate comprising:

• a lamination of a plurality of dielectric layers which each comprise an organic material and are each provided with a wiring conductor of a metallic foil on at least one surface of upper and bottom surfaces of the respective dielectric layers, the wiring conductors between which the dielectric layer is disposed being electrically connected with each other via a through conductor formed in the dielectric layer, wherein the dielectric layers each individually are composed of a liquid crystal polymer layer and cladding layers which are formed by laminating a first layer in which from 60% by volume to 80% by volume of inorganic insulating fillers are contained in a polyphenyleneether-type organic substance, a second layer in which from 40% by volume to 60% by volume of inorganic insulating fillers are contained in polyphenyleneether-type organic substance and a third layer in which from 20% by volume to 40% by volume of inorganic insulating fillers are contained in the polyphenyleneether-type organic substance in this order on each of upper and bottom surfaces of the liquid crystal polymer layer.

A multi-layer wiring substrate comprising:

• a lamination of a plurality of dielectric layers which each comprise an organic material and are each provided with a wiring conductor of a metallic foil on at least one surface of upper and bottom surfaces of the respective dielectric layers, the wiring conductors between which the dielectric layer is disposed being electrically connected with each other via a through conductor formed in the dielectric layer, wherein the dielectric layers each individually are composed of a liquid crystal polymer layer and cladding layers each comprising a polyphenyleneether-type organic substance and another organic substance having a lower Young's modulus than that of the former organic substance formed on upper and bottom surfaces of the liquid crystal polymer layer, and wherein, in the liquid crystal polymer layer, coefficient of thermal expansion thereof in a longitudinal direction is from −20 ppm/° C. to 20 ppm/° C. and Young's modulus thereof is 2 GPa or more and, in the cladding layer, the Young's modulus in a longitudinal direction is from 0.2 GPa to 1.5 GPa.