Patent ID: 8859077
Filing Date: 2014-10-14
Classification: H05K,Y10T

Abstract:
1. 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, wherein: an outermost resin insulation layer on the second main surface side of the laminate structure has a plurality of openings which expose portions of terminal outer surfaces of the second-main-surface-side connection terminals; the second-main-surface-side connection terminals are primarily comprised of a copper layer, and peripheral portions of the terminal outer surfaces of the second-main-surface-side connection terminals are covered by the outermost resin insulation layer; and a dissimilar metal layer made of at least one metal which is lower in etching rate than copper is formed between an inner main surface of the outermost resin insulation layer and at least the peripheral portions of the terminal outer surfaces.