Multilayer circuit board and a method for fabricating the same

Abstract

An interlayer connection wiring penetrating each of resin films constituting a multilayer circuit board and a surface wiring connected to the interlayer connection wiring are formed in predetermined positions on surfaces of each resin film. The resin films are laminated while being positioned so that the interlayer connection wiring of one of each adjacent pair of the circuit bases is superposed on a part of the surface wiring of the other, and are thereafter treated under a high-temperature and high-pressure condition to be combined with each other. If a resin film formed of a thermoplastic resin is adopted, the laminated resin films are combined by intermixing the interfaces of each adjacent pair of resin films. As the resin films shrink when the laminated resin films is cooled to ordinary temperature, a compressive force is applied to the contact surfaces of the interlayer connection wiring and the surface wiring. A resin block in which metal wires disposed parallel to each other are embedded is sliced perpendicularly to the metal wires to form resin films each having interlayer connection wiring elements with projections formed on opposite end portions of each wiring element. The projections are utilized to ensure reliable connections between the interlayer connection wiring of one of each adjacent pair of resin films and the surface wiring formed on the other.

Dependencies are inferred from the claim text.