Multilayer printed wiring board

Abstract

A multilayer printed wiring board includes a core base material having a penetrating portion, a low-thermal-expansion substrate accommodated inside the penetrating portion of the core base material and having a first surface for mounting a semiconductor element and a second surface on the opposite side of the first surface, a first through-hole conductor provided inside the low-thermal-expansion substrate and provided for electrical connection between the first surface and the second surface of the low-thermal-expansion substrate, a filler filled in a gap between the low-thermal-expansion substrate and an inner wall of the core base material, and a wiring layer formed on at least one of the first surface and the second surface of the low-thermal-expansion substrate and having a resin insulation layer and a conductive layer. The wiring layer has a via conductor connecting the first through-hole conductor and the conductive layer.

1 . A method for manufacturing a multilayer printed wiring board, comprising:
 providing a core base material having a penetrating portion and placed on a support material;   mounting a low-thermal-expansion substrate having a through-hole conductor on the support material such that the low-thermal-expansion substrate is placed in the penetrating portion of the core base material;   forming at least one insulation layer on the low-thermal-expansion substrate and the core base material such that a portion of an insulating material of the insulation layer is filled in a gap between the low-thermal-expansion substrate and an inner wall of the core base material and that the low-thermal-expansion substrate is fixed to the core base material;   forming a conductive layer on the insulation layer;   forming inside the insulation layer a via conductor electrically connected to the conductive layer; and   removing the support material after the low-thermal-expansion substrate is fixed to the core base material.   
     
     
         2 . The method for manufacturing a multilayer printed wiring board according to  claim 1 , further comprising:
 forming, on the low-thermal-expansion substrate, a buildup structure comprising an insulation layer and a conductive layer,   wherein the low-thermal-expansion substrate having the buildup structure is mounted on the support material.   
     
     
         3 . The method for manufacturing a multilayer printed wiring board according to  claim 1 , further comprising:
 forming, on the low-thermal-expansion substrate, a buildup structure comprising a plurality of insulation layers and a plurality of conductive layers alternately formed on the low-thermal-expansion substrate; and   forming a solder bump on an outermost conductive layer among the plurality of conductive layers,   wherein the low-thermal-expansion substrate having the solder bump is mounted on the support material.   
     
     
         4 . The method for manufacturing a multilayer printed wiring board according to  claim 2 , wherein the forming of the buildup layer comprises forming a via conductor electrically connecting the through-hole conductor of the low-thermal-expansion substrate and the conductive layer of the buildup structure. 
     
     
         5 . The method for manufacturing a multilayer printed wiring board according to  claim 3 , wherein the forming of the buildup layer comprises forming a via conductor electrically connecting the through-hole conductor of the low-thermal-expansion substrate and the conductive layer of the buildup structure. 
     
     
         6 . The method for manufacturing a multilayer printed wiring board according to  claim 1 , wherein the low-thermal-expansion substrate includes a low-thermal-expansion resin having a thermal expansion coefficient in a range of 2.5 to 10 ppm. 
     
     
         7 . The method for manufacturing a multilayer printed wiring board according to  claim 2 , wherein the buildup structure is formed such that at least a portion of the buildup structure is positioned inside the penetrating portion of the core base material. 
     
     
         8 . The method for manufacturing a multilayer printed wiring board according to  claim 3 , wherein the buildup structure is formed such that at least a portion of the buildup structure is positioned inside the penetrating portion of the core base material. 
     
     
         9 . The method for manufacturing a multilayer printed wiring board according to  claim 2 , wherein the buildup structure is formed such that at least a portion of the conductive layer of the buildup structure is positioned inside the penetrating portion of the core base material. 
     
     
         10 . The method for manufacturing a multilayer printed wiring board according to  claim 3 , wherein the buildup structure is formed such that at least a portion of the conductive layer of the buildup structure is positioned inside the penetrating portion of the core base material. 
     
     
         11 . The method for manufacturing a multilayer printed wiring board according to  claim 2 , wherein the core base material has Young's modulus greater than Young's modulus of a resin material of the insulation layer of the buildup structure. 
     
     
         12 . The method for manufacturing a multilayer printed wiring board according to  claim 2 , wherein the buildup structure has a thickness less than a thickness of the low-thermal-expansion substrate. 
     
     
         13 . The method for manufacturing a multilayer printed wiring board according to  claim 1 , wherein a tapered corner portion is formed in the low-thermal-expansion substrate. 
     
     
         14 . The method for manufacturing a multilayer printed wiring board according to  claim 2 , wherein a plurality of mounting pads are formed on the buildup structure to mount a semiconductor element. 
     
     
         15 . The method for manufacturing a multilayer printed wiring board according to  claim 1 , further comprising forming a resin layer on the low-thermal-expansion substrate. 
     
     
         16 . The method for manufacturing a multilayer printed wiring board according to  claim 15 , further comprising forming a conductive layer on the resin layer of the low-thermal-expansion substrate. 
     
     
         17 . The method for manufacturing a multilayer printed wiring board according to  claim 2 , wherein the through-hole conductor is extended through the insulation layer of the buildup structure. 
     
     
         18 . The method for manufacturing a multilayer printed wiring board according to  claim 3 , wherein the through-hole conductor is extended through the insulation layer of the buildup structure. 
     
     
         19 . The method for manufacturing a multilayer printed wiring board according to  claim 4 , wherein the through-hole conductor is tapered in a first direction, and the via conductor formed in the buildup layer is tapered in a second direction opposite to the first direction. 
     
     
         20 . The method for manufacturing a multilayer printed wiring board according to  claim 5 , wherein the through-hole conductor is tapered in a first direction, and the via conductor formed in the buildup layer is tapered in a second direction opposite to the first direction.