To provide a multilayer wiring board and its producing method employing a conductor, e.g. conductive paste, for interlayer electrical connection in which highly reliable fine via holes are realized.
Via holes 104 opened in the thickness direction of an electric insulating basic material 102 are filled with conductive paste 105 to form wiring layers 107 in a specified pattern on the opposite sides of the electric insulating basic material, and the wiring layers are connected electrically with conductive paste. In such a wiring board, surface roughness on the side abutting against the electric insulating basic material of at least one wiring layer is set not larger than the mean particle size of conductive particles contained in the conductive paste. Since only the resin component in the conductive paste is discharged and conductive particles in the conductive paste are left in the via holes, the conductive paste is made compact, thus realizing highly reliable via hole connection having low initial resistance.
NAKAMURA SADASHI
HIGASHIYA HIDEKI
Next Patent: METHOD OF MANUFACTURING METAL FOIL LAMINATE AND WIRING BOARD