| 摘要 |
A circuit board includes a lower sub-board, a connection layer on the lower sub-board, and an upper sub-board on the connection layer. The lower sub-board includes a first base layer having an upper surface, and a first wiring pattern provided on the upper surface of the first base layer. The upper sub-board includes a second base layer having a lower surface, and a second wiring pattern provided on the lower surface of the second base layer. The connection layer includes an insulating layer having a lower surface and an upper surface, the lower surface of connection layer being situated on the upper surface of the first base layer, the upper surface of connection layer being situated on the lower surface of the second base layer, and a via-conductor passing through the insulating layer and connected to the first and second wiring patterns. The upper sub-board and the connection layer expose a portion of the upper surface of the lower sub-board. The insulating layer includes thermosetting resin, inorganic filler dispersed in the thermosetting resin, and elastomer dispersed in the thermosetting resin. This circuit board connects the sub-boards to each other via a via-conductor densely. |
