| 摘要 |
PROBLEM TO BE SOLVED: To provide a multilayer wiring board by which the connectivity between via holes and metal wiring layers can be improved. SOLUTION: The multilayer wiring board is composed of insulating layers (20a and 30a), first metal wiring layers (10b and 10c) which are provided on one side of the insulating layers, via holes (91, 92 and 93) which are formed by filling prepared holes (91a, 92a and 93a) for via holes in approximately conic form with a bottom with conductive material, and second metal wiring layers 20b and 30b which are connected to the via holes and provided on the other side of the insulating layers in conduction with the first metal wiring layers. The prepared holes for via holes have an aspect ratio of 1 or larger and their diameter is expanding on the side of the metal wiring layers. Since the diameter of the prepared holes for via holes is expanding on the side of the first metal wires, the connection area between the via holes and the first metal wiring layers is increased and the connectivity is improved. |
