| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of preventing warpage of a printed wiring board, which prevents the board from being bent backward due to bending stresses, which are generated in the surface and in the rear of the board, even if mounting components are mounted on the surface of the board. SOLUTION: In a printed wiring board 1 to which soldering is applied by a reflow after mounting components 2 are mounted on the surface 1a of the board 1, patterns 4 are provided on the rear 1b of the board 1, and at the same time, solders 3 are respectively made to adhere to the patterns 4, and a bending stress to oppose to a bending stress, which is generated in the surface 1a of the board 1 by the shrinkage of the solders 3 subsequent to the reflow is generated in the rear 1b of the board 1. Thereby, the bending stress, which is generated in the side of the surface 1a of the board 1 and the bending stress which is generated in the side of the rear 1b of the board 1 become equal to each other and the warpage of the board 1 can be prevented from occurring.
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