主权项 |
1. A method of manufacturing a multilayer wiring substrate comprising a laminate structure in which a plurality of resin insulation layers made primarily of a same resin insulation material, and a plurality of conductive layers are laminated alternately in multilayer arrangement, a plurality of first-main-surface-side connection terminals being disposed on a first main surface side of the laminate structure, a plurality of second-main-surface-side connection terminals being disposed on a second main surface side of the laminate structure, the plurality of conductive layers being formed in the plurality of resin insulation layers and interconnected by means of via conductors whose diameters increase toward the first main surface side of the laminate structure or the second main surface side of the laminate structure, the method comprising:
a base-material preparation step of preparing a base material on which a metal foil is separably laminated; an insulation-layer/conductor-portion forming step including
a step of laminating on the metal foil a build-up material made primarily of a resin insulation material that is not photocurable, to thereby form an outermost resin insulation layer on the second main surface side of the laminate structure,a step of forming openings in the outermost resin insulation layer, anda step of forming a metal conductor portion in each of the openings and on a corresponding portion of the outermost resin insulation layer around the each of the openings; a build-up step including
a step of laminating the plurality of resin insulation layers made primarily of the same resin insulation material, and the plurality of conductive layers alternately in multilayer arrangement, to thereby form the laminate structure, anda step of forming the first-main-surface-side connection terminals on the first main surface side of the laminate structure; a base-material removing step of, after the build-up step, removing the base material to thereby expose the metal foil; and a connection-terminal forming step of removing the metal foil and at least a portion of each metal conductor portion, to thereby form a concave portion in each of the plurality of second-main-surface-side connection terminals. |