Patent ID: 6524892
Filing Date: 2003-02-25
Classification: H01L,H05K

Abstract:
A fabricating method of a multilayer flexible wiring board, said method comprising the steps of:laminating a flexible wiring board piece having a metal wiring, in which metal coating is exposed on at least a part of surface of said metal wiring, to another flexible wiring board piece having metal projections on the surface of which metal coating is formed, wherein one of or both of the surface of said metal coating formed on said metal wiring and on the surface of said metal projections is composed of soft metal coating having a Vickers' harness of 80 kgf/mm2 or lower; interposing a thermoplastic film between said flexible wiring board pieces; adhering said flexible wiring board pieces to each other by said thermoplastic film; applying, after adhering said flexible wiring board pieces to each other by said thermoplastic film, an ultrasonic wave to the laminated flexible wiring board pieces while the metal coating formed on said metal wiring is in contact with the metal coating formed on the surface of said metal projections to connect said metal wiring with said metal projections; and pressing at least one of said flexible wiring board pieces to contact the metal coatings with each other while applying ultrasonic wave.