| 摘要 |
PURPOSE:To reduce the occupying area of a through-hole, and to thin a multilayer printed wiring board by electrically connecting circuit conductor layers mutually through the through-hole of an insulating substrate and a blind via hole formed to an insulating resin layer. CONSTITUTION:Insulating layers by circuit conductor layers 10, 13 and insulating resin layers 11 are formed alternately on both the surface and rear of an insulating substrate 7 and formed in a multilayer shape in the arbitrary number of layers, an internal-layer wiring board, in which the circuit conductor layers among the layers are connected electrically through a through-hole 8 shaped to the insulating substrate and fine holes, which are formed to the insulating resin layers and are not penetrated, is constituted, and metallic copper foil 15 is bonded with an outermost layer through adhesive layers 14 using a prepreg insulating sheet, thus forming circuit conductor layers 18. Accordingly, the circuit conductor layers as internal layers are also connected mutually by the fine holes shaped to the insulating resin layers, thus decreasing the number of the through-holes while thinning a multilayer printed wiring board because no thick prepreg sheet is used as inter-layer insulating layers. |
