| 摘要 |
PURPOSE:To relax restrictions about the positions of through holes to connect an interlayer wiring circuit conductor layer and enhance the degree of freedom for circuit design and increase the density of the wiring circuit in a multilayer printed board used in a wide field of electronic components. CONSTITUTION:A wiring circuit conductor layer 7, which is an inner layer, is installed on the both front and rear sides of an insulation board 6 where a first through hole 8 is made to connect the wiring circuit conductor layer 8 electrically. Then, insulation resin is filled into the through hole 8. Further there an insulation resin layer 9 is made on the wiring circuit conductor layer 7 which is an inner layer. In addition, a wiring circuit conductor layer 10, which is an outermost layer, is installed to both front and back sides of the insulation resin layer respectively where a second through hole 11 is made inside the first through hole 8 in order to connect the wiring circuit conductor layer 10 electrically. |
