| 摘要 |
PROBLEM TO BE SOLVED: To provide a multilayer printed wiring board in which an internal- layer circuit pattern and an external-layer circuit pattern are connected electrically. SOLUTION: This wiring board 1 is provided with an insulating board 2 which is used as a base. In addition, it is provided with a first circuit pattern 3 which is formed at least on one face out of the surface and the rear surface of the insulating board 2. In addition, it is provided with an insulating layer 4 which is coated and formed on the insulating board 2 on the side of the face forming the first circuit pattern 3, in which calcium carbonate 4b soluble with reference to an oxidizing agent is diffused into a resin hardly soluble with reference to the oxidizing agent, and in which a bottomed hole 5 for connection is bored and formed from the surface side by a laser beam so as to expose the first circuit pattern 3. In addition, it is provided with a second circuit pattern 7 which is formed in such a way that the surface of the insulating layer 4 and the inner wall of the bottomed hole 5 for connection bored and formed in the insulating layer are roughened. At this time, the first and second circuit patterns 3, 7 are electrically connected to each other via the bottomed hole 5 for connection. |
