| 摘要 |
A wiring substrate provides an inner wiring substrate having through hole portions. On at least one main surface of the inner wiring substrate, a plurality of build up layers are laminated. The build up layers have a stacked via, for example, as a power source system via. The stacked via is formed by stacking the vias in multiple steps to form a straight line. The stacked via has a large diameter via which is larger than other via constituting the stacked via, or is constituted of large diameter vias larger than other via in the same build up layer.
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