Patent ID: 7178234

Claim:
A method of manufacturing a multi-layer printed circuit board comprising at least the following steps (a) to (f): (a) forming lower interlayer resin insulating layers on both sides of a core substrate, respectively; (b) forming through holes penetrating said core substrate and said lower interlayer resin insulating layers; (c) forming on sides of the through holes vertical electrical conductors extending between the lower interlayer resin insulating layers and extending at least along a length of the through holes; (d) forming conductor circuits on exposed surfaces of the lower interlayer resin insulating layers opposite the core substrate; (e) forming upper interlayer resin insulating layers on said lower interlayer resin insulating layers, respectively; and (f) forming via holes in said upper interlayer resin insulating layers, the via holes connected to external connection terminals and formed right on part of said through holes.