Multilayer wiring substrate, and method of manufacturing the same

Abstract

A plurality of openings are formed in a resin insulation layer on a top surface side of a wiring laminate portion, and a plurality of openings are formed in a resin insulation layer on a bottom surface side thereof. A plurality of connection terminals are disposed to correspond to the openings. Peripheral portions of terminal outer surfaces of the connection terminals are covered by the resin insulation layer on the top surface side, and peripheral portions of terminal outer surfaces of the connection terminals are covered by the resin insulation layer on the bottom surface side. Each of the second-main-surface-side connection terminals has a concave portion at the center of the terminal outer surface, and the deepest portion of the concave portion is located on the interior side in relation to the peripheral portion of the terminal outer surface.

What is claimed is: 
     
         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, and 
 a 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, and 
 a 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.   
     
     
         2 . The method of manufacturing a multilayer wiring substrate according to  claim 1 ,
 wherein the step of forming openings in the outermost resin insulating layer is performed after the step of laminating on the metal foil a build-up material, and includes a step of performing laser drilling on the outermost resin insulation layer to thereby form the openings, the openings exposing portions of the metal foil;   the method further comprising, after the step of performing laser drilling,
 a step of forming a plating resist film on the outermost resin insulation layer, and 
 a step of forming, at positions corresponding to the openings, additional openings in the plating resist film which are greater in area than the openings; 
   wherein the step of forming the metal conductor portion is performed after the steps of forming a plating resist film and forming additional openings, and further includes
 a step of performing electro plating so as to form the metal conductor portion in each of the openings and the additional openings, and 
 a step of removing the plating resist film. 
   
     
     
         3 . 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 performing copper plating so as to form metal-conductor-portion lower layers, which partially constitute the metal conductor portions, on the metal foil; 
 a step of laminating on the metal foil and the metal-conductor-portion lower layers 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 exposing upper end surfaces of the metal-conductor-portion lower layers from the outermost resin insulation layer; 
 a step of forming a plating resist film on the outermost resin insulation layer, 
 a step of forming openings at positions corresponding to the upper end surfaces of the metal-conductor-portion lower layers, the openings having an area greater than an area of the upper end surfaces; 
 a step of performing copper plating so as to form metal-conductor-portion upper layers, which partially constitute the metal conductor portions in the openings; and 
 a step of removing the plating resist film; 
   a build-up step including
 a step of laminating the plurality of resin insulation layers made primarily of the same resin insulation material, and a plurality of conductive layers alternately in the multilayer arrangement, to thereby form the laminate structure, and 
 a 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.