A method that minimizes adjustment of a wiring layer in reducing a warpage of a multilayered substrate and enables location of a part of a wiring layer that needs correction in order to reduce the warpage. The difference in average coefficient of thermal expansion, Δα, varies in a substrate. The method focuses in on the difference in Δα with a great length scale (low frequency) having a relatively significant effect on the warpage compared to the difference in Δα with a smaller length scale (high frequency) and corrects only the difference in Δα with a greater length scale. The distribution of the difference in Δα in a plane of substrate is determined. Then digital filtering is performed to extract only the difference in Δα with a low frequency and the difference in Δα between before and after correction, thereby revealing a part that requires correction.