| 摘要 |
The deterioration of dielectric breakdown strength arising from an opening of a metal plate is prevented and the reliability as a circuit board is enhanced. A circuit board is provided with a metal plate, having openings, as core material. The opening is provided in a manner that the size of the opening gradually increases from a lower surface side toward an upper surface side of the metal plate. On both surface sides of the metal plate there are provided wiring patterns, respectively, via insulating layers. The insulating layer provided on an upper region of the opening and the corresponding wiring pattern are provided such that they have a recess on the upper surface of them. To electrically connect each wiring pattern, the circuit board further includes a conductor which penetrates the metal plate via the opening and which connects the wiring patterns with each other. An LSI chip is directly coupled to the upper surface side of the metal plate via a solder ball.
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