Patent ID: 7576288

Claim:
A multilayer wiring board comprising (i) a plurality of single-sided wiring boards having a wiring pattern formed on one side of a substrate made of an insulating material and two-layer conductor posts made of copper and a metal or copper and an alloy, each of said conductor posts projecting from said wiring pattern to a side of said substrate opposite from said wiring pattern, with each substrate other than that of an outermost layer having, on the side opposite from said conductor posts, a plurality of pads for making connection to the conductor posts, and said wiring pattern having no surface coating, (ii) a flexible wiring board having on at least one side thereof the pads for connection to said conductor posts and comprising a wiring pattern with surface coating applied on a flexible portion but substantially no surface coating applied on a multilayer rigid portion, and (iii) an adhesive layer having a flux function whereby respective boards are laminated integrally, forming the multilayer rigid portion, wherein said conductor posts and pads are connected by a metal or an alloy through the medium of said adhesive layer, and said wiring patterns are electrically connected.