Method of manufacturing multilayer wiring substrate, and multilayer wiring substrate

Abstract: The present invention provides a method of manufacturing a multilayer wiring substrate, which can preserve the dimensional stability of a conductor pattern at a fine pitch, solve the restriction on a process from the viewpoint of material selection, and further reduce a manufacturing cost, and a multilayer wiring substrate. A second wiring substrate formed on a supporting sheet made of metal and an adhesive layer are partially stacked on a predetermined region of a first wiring substrate by using the supporting sheet. After the lamination of the second wiring substrate, the supporting sheet is finally etched and removed. The second wiring substrate is stacked only on the portion required to be multilayered on the first wiring substrate to thereby reduce the amount of the construction material of the second wiring substrate. (end of abstract)