Method of manufacturing a wiring board having via structures

Abstract

A method of manufacturing a wiring board includes: forming an outer through hole in a core substrate; filling the outer through hole with an insulation resin; forming a first conductive layer on a surface of the insulation resin at a portion where a core connecting via is formed; forming a land around the first conductive layer; laminating the wiring layer on the core substrate after the forming of the first conductive layer and the forming of the land; forming an inner through hole having a smaller diameter than that of the outer through hole and penetrating through the core substrate and the wiring layer so as to penetrate through the insulation resin; and coating a first conductive film on an inner wall surface of the inner through hole, in which the core substrate and the first conductive film are electrically connected through the first conductive layer and the land.

What is claimed is: 
     
         1 . A wiring board, comprising:
 a core substrate having conductivity;   a wiring layer laminated on the core substrate; and   a plurality of penetrating-through hole vias that penetrate through the core substrate and the wiring layer,   wherein a core connecting via electrically connected with the core substrate among the plurality of penetrating-through hole vias includes:   an outer through hole that penetrates through the core substrate;   an inner through hole that has a smaller diameter than that of the outer through hole and penetrates through the core substrate and the wiring layer;   an insulation resin part formed between the outer through hole and the inner through hole;   a first conductive film coated on an inner wall surface of the inner through hole; and   a core connecting conductive part formed on a surface of and around the insulation resin part to electrically connect the core substrate and the first conductive film.   
     
     
         2 . A structure of a core connecting via electrically connected with a core substrate among a plurality of penetrating-through hole vias provided on a wiring board including the core substrate having conductivity, the structure comprising;
 an outer through hole that penetrates through the core substrate;   an inner through hole that has a smaller diameter than that of the outer through hole and penetrates through the core substrate and a wiring layer laminated on the core substrate;   an insulation resin part formed between the outer through hole and the inner through hole;   a first conductive film coated on an inner wall surface of the inner through hole; and   a core connecting conductive part formed on a surface of and around the insulation resin part to electrically connect the core substrate and the first conductive film.