Patent ID: 8631568

Claim:
A printed wiring board manufacturing method, comprising: weaving a glass fiber cloth with warp yarns and weft yarns such that the warp yarns and the weft yarns are visually distinguishable at least a region; impregnating the glass fiber cloth with a resin to fabricate a substrate; forming a copper foil on at least one surface of the substrate to fabricate a core substrate; removing the copper foil within the region on the core substrate to form an opening; detecting a pitch between the warp yarns or between the weft yarns presented in the opening; determining a pitch between a pair of differential wirings to be patterned based on the detected pitch between the warp yarns or between the weft yarns; and patterning the pair of differential wirings on the core substrate in accordance with the determined pitch between the pair of differential wirings.