An object of the invention is to provide a method for fabricating a printed wiring board that can suppress warping of the printed wiring board and can improve the yield of semiconductor chip mounting and enhance the reliability of a semiconductor package. The printed wiring board fabrication method according to the invention is a method for fabricating a printed wiring board having a through-hole in a core layer, wherein the printed wiring board fabrication method includes the step of applying a laser from one side of the core layer to a position where the through-hole is to be formed in the core layer and the step of applying a laser to the same position from the opposite side of the core layer.
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