Multilayer printed wiring board

Abstract

A multilayer printed wiring board including a core substrate, a first conductor layer on a first surface of the substrate, a second conductor layer on a second surface of the substrate, a third conductor layer inside the substrate between the first and second conductor layers, a conductive post connecting the third conductor layer with the first and second conductor layers, a first conductor circuit on the first surface of the substrate, a second conductor circuit on the second surface of the substrate, and a through hole formed through the substrate and connecting the first and second conductor circuits. The through hole is not connected to the third conductor layer, the third conductor layer has thickness larger than thicknesses of the first and second conductor layers, each of the first, second and third conductor layers forms one of power supply and ground layers, and the through hole forms a signal line.

1 . A multilayer printed wiring board comprising:
 a core substrate having a first surface and a second surface on an opposite side of the first surface;   a first conductor layer formed on the first surface of the core substrate;   a second conductor layer formed on the second surface of the core substrate;   a third conductor layer formed inside the core substrate between the first conductor layer and the second conductor layer;   a conductive post connecting the third conductor layer with the first and second conductor layers;   a first conductor circuit formed on the first surface of the core substrate;   a second conductor circuit formed on the second surface of the core substrate; and   a through hole formed through the core substrate and connecting the first conductor circuit and the second conductor circuit,   wherein the through hole is not connected to the third conductor layer, the third conductor layer has a thickness which is larger than thicknesses of the first and second conductor layers, each of the first, second and third conductor layers forms one of a power supply layer and a ground layer, and the through hole forms a signal line.   
     
     
         2 . The multilayer printed wiring board according to  claim 1 , wherein at least one of the first and second conductor layers has a side face having a rounded taper form tapering toward the core substrate. 
     
     
         3 . The multilayer printed wiring board according to  claim 1 , further comprising:
 an interlayer insulation layer formed over the first surface of the core substrate;   a conductive layer formed over the interlayer insulation layer; and   a via hole providing electrical connection between the first the conductive layer and one of the first conductor layer and the first conductor circuit.   
     
     
         4 . The multilayer printed wiring board according to  claim 1 , wherein at least one of the first and second conductor layers has a side face which makes an angle, Θ, formed by a horizontal face of the core substrate and a straight line connecting a top end and a bottom end of the side face, and the angle, Θ, satisfies 2.8<tan Θ<55. 
     
     
         5 . The multilayer printed wiring board according to  claim 1 , wherein at least one of the first and second conductor layers has a side face which makes an angle, Θ, formed by a horizontal face of the core substrate and a straight line connecting a top end and a bottom end of the side face, the angle, Θ, satisfies 2.8<tan Θ<55, and the side surface of the at least one of the first and second surface is one of a taper form and a rounded taper form. 
     
     
         6 . The multilayer printed wiring board according to  claim 1 , wherein at least one of the first and second conductor layers has a side face tapering toward the core substrate, and the side surface of the at least one of the first and second surface is one of a taper form and a rounded taper form. 
     
     
         7 . The multilayer printed wiring board according to  claim 1 , wherein the first, second and third conductor layers form power supply layers. 
     
     
         8 . The multilayer printed wiring board according to  claim 1 , wherein the first, second and third conductor layers form ground layers. 
     
     
         9 . The multilayer printed wiring board according to  claim 1 , further comprising:
 an interlayer insulation layer formed over the first surface of the core substrate;   a conductive layer formed over the interlayer insulation layer;   a via hole providing electrical connection between the conductive layer and one of the first conductor layer and the first conductor circuit; and   a capacitor provided over the interlayer insulation layer and electrically connected to the first, second and third conductor layers and to the first and second conductor circuits.   
     
     
         10 . The multilayer printed wiring board according to  claim 1 , further comprising a capacitor electrically connected to the first, second and third conductor layers and to the first and second conductor circuits.