| 摘要 |
PROBLEM TO BE SOLVED: To provide a thin printed wiring board with less warp.SOLUTION: A printed wiring board 10 has a core material 20z having a first surface F and a second surface S, an upper build-up layer 55F formed on the first surface of the core material, and a lower build-up layer 55S formed on the second surface of the core material. The upper build-up layer has a plurality of upper conductor layers. The lower build-up layer has a plurality of lower conductor layers. The sum of thickness of respective lower conductor layers is larger than the sum of thickness of respective upper conductor layers, and the difference is larger than 1 μm. An electronic component is mounted on the upper build-up layer.SELECTED DRAWING: Figure 1 |
