| 摘要 |
PROBLEM TO BE SOLVED: To reduce warpage of a printed wiring board.SOLUTION: A printed wiring board has a core substrate, an upper build-up layer, an upper solder resist layer, and a lower solder resist layer. The lower solder resist layer is only one layer, and has a reinforcement material. A resin insulation layer constituting the upper build-up layer has no reinforcement material. When a thickness of the lower solder resist is represented by A, the sum of the thicknesses of all of the upper resin insulation layers included in the upper build-up layer is represented by B, a thickness of the core substrate is represented by C, and a thickness of the upper solder resist layer is represented by D, the printed wiring board satisfies a relational expression (1): 0.3<A/(B+D)<1.0 and a relational expression (2): 0.16<(B+D)/(A+C)<0.48.SELECTED DRAWING: Figure 5 |
