Wiring board and method for manufacturing the same

Abstract

A wiring board includes a first multilayer wiring board having a built-in electronic component and first conductive layers, a second multilayer wiring board having second conductive layers and positioned such that the second multilayer wiring board has a surface facing a surface of the first multilayer wiring board, and an adhesive layer including an adhesive sheet and interposed between the first multilayer wiring board and the second multilayer wiring board such that the adhesive layer is adhering the first multilayer wiring board and the second multilayer wiring board. The first multilayer wiring board has a first pad on the surface of the first multilayer wiring board, the second multilayer wiring board has a second pad on the surface of the second multilayer wiring board, and the first pad and the second pad are positioned such that the first pad and the second pad face each other across the adhesive layer.

What is claimed is: 
     
         1 . A wiring board, comprising:
 a first multilayer wiring board comprising a built-in electronic component and a plurality of first conductive layers;   a second multilayer wiring board having a plurality of second conductive layers and positioned such that the second multilayer wiring board has a surface facing a surface of the first multilayer wiring board; and   an adhesive layer comprising an adhesive sheet and interposed between the first multilayer wiring board and the second multilayer wiring board such that the adhesive layer is adhering the first multilayer wiring board and the second multilayer wiring board,   wherein the first multilayer wiring board has a first pad on the surface of the first multilayer wiring board, the second multilayer wiring board has a second pad on the surface of the second multilayer wiring board, and the first pad and the second pad are positioned such that the first pad and the second pad face each other across the adhesive layer.   
     
     
         2 . The wiring board according to  claim 1 , wherein the adhesive layer has a penetrating hole connecting the first pad and the second pad, and the penetrating hole of the adhesive layer has a hole diameter which is set greater than the first pad and the second pad such that the penetrating hole has a clearance between the first pad and the penetrating hole and a clearance between the second pad and the penetrating hole. 
     
     
         3 . The wiring board according to  claim 2 , wherein the clearance between the penetrating hole and the first pad is filled with a resin, and the clearance between the penetrating hole and the second pad is filled with a resin. 
     
     
         4 . The wiring board according to  claim 1 , wherein the adhesive sheet of the adhesive layer has an opening which accommodates the first pad and the second pad. 
     
     
         5 . The wiring board according to  claim 1 , wherein the plurality of first conductive layers of the first multilayer wiring board includes a first conductive layer formed on the surface of the first multilayer wiring board and including the first pad, the plurality of second conductive layers of the second multilayer wiring board includes a second conductive layer formed on the surface of the second multilayer wiring board and including the second pad, and the first conductive layer and the second conductive layer comprise wirings which do not face each other, excluding the first pad and the second pad. 
     
     
         6 . The wiring board according to  claim 1 , wherein the plurality of first conductive layers of the first multilayer wiring board includes a first conductive layer formed on the surface of the first multilayer wiring board, the first conductive layer has a plurality of wiring portions and includes the first pad, the plurality of second conductive layers of the second multilayer wiring board includes a second conductive layer formed on the surface of the second multilayer wiring board and consisting of the second pad, and the first pad is set to have a smaller area than the second pad. 
     
     
         7 . The wiring board according to  claim 1 , wherein the plurality of first conductive layers of the first multilayer wiring board includes a first conductive layer formed on the surface of the first multilayer wiring board, the first conductive layer has a plurality of wiring portions and includes the first pad, the plurality of second conductive layers of the second multilayer wiring board includes a second conductive layer formed on the surface of the second multilayer wiring board and consisting of the second pad, and the first pad is set to have a greater area than the second pad. 
     
     
         8 . The wiring board according to  claim 1 , wherein at least one of the first multilayer wiring board and the second multilayer wiring board includes a plurality of filled via conductors comprising plated materials connecting at least one of the plurality of first conductive layers and the plurality of second conductive layers, respectively. 
     
     
         9 . The wiring board according to  claim 8 , wherein at least one of the first pad and the second pad is positioned such that one of the filled via conductors is in contact with at least one of the first pad and the second pad. 
     
     
         10 . The wiring board according to  claim 9 , wherein the filled via conductors are formed in truncated cone shapes tapering in a lamination direction of the at least one of the first multilayer wiring board and the second multilayer wiring board, and the at least one of the first pad and the second pad is formed to make contact with a surface of the one of the filled via conductors in contact such that the surface of the one of the filled via conductors in contact is a surface having a larger diameter of a truncated cone shape. 
     
     
         11 . The wiring board according to  claim 1 , wherein at least one of the first multilayer wiring board and the second multilayer wiring board includes a plurality of via conductors connecting at least one of the plurality of first conductive layers and the plurality of second conductive layers, and the plurality of via conductors reverses a tapering direction more than twice. 
     
     
         12 . The wiring board according to  claim 1 , wherein at least one of the first pad and the second pad has a tin-plated layer formed on a surface of the at least one of the first pad and the second pad. 
     
     
         13 . The wiring board according to  claim 1 , wherein the second multilayer wiring board and the adhesive layer have substantially a same size. 
     
     
         14 . The wiring board according to  claim 1 , wherein the first multilayer wiring board comprises a first core substrate and a plurality of first insulation layers laminated on the first core substrate, the second multilayer wiring board comprises a second core substrate and a plurality of second insulation layers laminated on the second core substrate, and the first insulation layers, the second insulation layers and the adhesive sheet of the adhesive layer are made of a same material. 
     
     
         15 . The wiring board according to  claim 1 , further comprising:
 a third multilayer wiring board comprising a plurality of third conductive layers and positioned such that the third multilayer wiring board has a surface facing a second surface of the first multilayer wiring board; and   a second adhesive layer comprising an adhesive sheet and interposed between the first multilayer wiring board and the third multilayer wiring board such that the second adhesive layer is adhering the first multilayer wiring board and the third multilayer wiring board,   wherein the third multilayer wiring board has a third pad formed on the surface of the third multilayer wiring board such that the third pad faces a pad on the second surface of the first multilayer wiring board across the second adhesive layer interposed between the first multilayer wiring board and the third multilayer wiring board.   
     
     
         16 . The wiring board according to  claim 15 , wherein the plurality of second conductive layers in the second multilayer wiring board and the plurality of third conductive layers in the third multilayer wiring board have different numbers of conductive layers. 
     
     
         17 . The wiring board according to  claim 1 , wherein the first multilayer wiring board is a rigid wiring board, and the second multilayer wiring board is a rigid wiring board. 
     
     
         18 . The wiring board according to  claim 1 , wherein the first multilayer wiring board is a flex-rigid wiring board comprising a plurality of rigid wiring boards and a flexible wiring board connecting the rigid wiring boards. 
     
     
         19 . The wiring board according to  claim 1 , wherein the first multilayer wiring board has a built-in metal sheet formed in the first multilayer wiring board. 
     
     
         20 . A method for manufacturing a wiring board, comprising:
 preparing a first multilayer wiring board comprising a built-in electronic component and a plurality of first conductive layers and having a first pad on a surface of the first multilayer wiring board;   preparing a second multilayer wiring board comprising a plurality of second conductive layers and having a second pad on a surface of the second multilayer wiring board;   setting the surface of the first multilayer wiring board and the surface of the second multilayer wiring board such that the first pad and the second pad face each other; and   interposing between the surface of the first multilayer wiring board and the surface of the second multilayer wiring board an adhesive layer comprising an adhesive sheet such that the first multilayer wiring board and the second multilayer wiring board are adhered through the adhesive layer and that the first pad and the second pad face each other across the adhesive layer.   
     
     
         21 . The method for manufacturing a wiring board according to  claim 20 , further comprising forming in the adhesive layer a penetrating hole having a hole diameter which is made greater than diameters of the first and second pads such that the penetrating hole accommodates the first pad and the second pad through the adhesive layer. 
     
     
         22 . The method for manufacturing a wiring board according to  claim 20 , wherein at least one of the first multilayer wiring board and the second multilayer wiring board comprises a plurality of filled vias comprising plated materials and having truncated cone shapes, the plurality of filled vias is formed such that the truncated cone shapes are tapering in a lamination direction of the at least one of the first multilayer wiring board and the second multilayer wiring board and connect at least one of the plurality of first conductive layers and the plurality of the second conductive layers, and the at least one of the first pad and the second pad is formed to make contact with a surface of the one of the filled via conductors in contact such that the surface of the one of the filled via conductors in contact is a surface having a larger diameter of a truncated cone shape. 
     
     
         23 . The method for manufacturing a wiring board according to  claim 20 , further comprising:
 preparing a third multilayer wiring board comprising a plurality of third conductive layers and having a third pad on a surface of the third multilayer wiring board;   setting a second surface of the first multilayer wiring board and the surface of the third multilayer wiring board such that the third pad and a pad on the second surface of the first multilayer wiring board to face each other; and   interposing between the second surface of the first multilayer wiring board and the surface of the third multilayer wiring board a second adhesive layer comprising an adhesive sheet such that the first multilayer wiring board and the third multilayer wiring board are adhered through the second adhesive layer and that the third pad and the pad on the second surface of the first multilayer wiring board face each other across the second adhesive layer.   
     
     
         24 . The method for manufacturing a wiring board according to  claim 23 , wherein the plurality of second conductive layers in the second multilayer wiring board and the plurality of third conductive layers in the third multilayer wiring board have different numbers of conductive layers.