| 摘要 |
PROBLEM TO BE SOLVED: To thin the wiring pitches of a multilayer wiring board, constituted of a plurality of resin insulating layers and metal wiring layers, and to provide the structure of the via hole of high electrical reliability, a forming method and the multilayer printed wiring board. SOLUTION: In the multilayer wiring board, the insulating layer constituted of a resin insulating film and a wiring layer constituted of a conductor film are alternately laminated. A flat or oval or rectangular via hole 14, where the minor diameter and the major diameter having different lengths of the opening part of the via hole which electrically connect wiring layers conducts the upper and lower metal wiring layers. |
