Patent ID: 8076589

Claim:
A multilayer wiring board having an any-layer IVH structure, the multilayer wiring board comprising: an insulating substrate having a via hole; conductive paste disposed in the via hole; and wiring layers coupled to each other with the conductive paste, wherein the wiring layers are not buried in the insulating substrate, wherein the insulating substrate has a thickness smaller than 40 μm, wherein substrate compressibility of the insulating substrate in a thickness direction is lower than 5%, wherein the conductive paste is disposed in the via hole of the insulating substrate by applying cover films to opposing surfaces of the insulating substrate, forming the via hole in the insulating substrate and the cover films, filling the via hole with the conductive paste, and then removing the cover films such that the conductive paste projects from each surface of the insulating substrate by a height equal to a thickness of the cover film removed from the surface, and wherein the height of the conductive paste is 25% or larger of the thickness of the insulating substrate.