| 摘要 |
<p>PROBLEM TO BE SOLVED: To mount surface mount electronic components with a high density by forming single or a plurality of recesses parts which are of reversed conic shape provided with a plurality of gaps and providing single or a plurality of lands which are electrically connected to wiring layers corresponding respectively to the gaps of the recessed parts, to the respective gaps of the recessed parts. SOLUTION: A multi-layered wiring board 31, which is of three-layer structure where conductive patterns 32A and 32B are respectively formed every layer, is provided with a recessed part 31A of almost a reversed square conic shape having gaps 31B and 31C where multi-layered conductive patterns 32A and 32B are respectively exposed in specified areas. In addition, a plurality of lands 41 is formed on the upper surface 31D of the board 31, facing a plurality of pads respectively at a specified pitch around the outermost circumference of a circuit face 40A of a semiconductor chip 40 in such a manner that the chip 40 is piled up together with semiconductor chips 34 and 35.</p> |
