| 摘要 |
PROBLEM TO BE SOLVED: To inhibit the stray capacity between an I/O terminal at a substrate side and an electrode for grounding on a substrate lower surface, at the same time, to improve an S parameter by effectively increasing the area of the electrode for grounding for improving transmission characteristics in a high-frequency signal, and to make large junction strength by increasing the junction area with the external apparatus of a semiconductor package. SOLUTION: There are a nearly rectangular parallelepiped substrate where a plurality of insulating layers are stacked and a recess 1a for accommodating a semiconductor device C on an upper surface is formed, and grooves 2 and 3 that are formed over the portion between the upper and lower surfaces of the substrate 1 on the external surface of a sidewall 1e of the substrate 1 and at the same time have conductor layers 2a, 4a, and 4b that are deposited on an inner surface. In this case, the width of the groove 3 that is formed in a lowermost insulating layer 1d is set wider than the groove 2 that is formed in other insulating layers.
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