Printed wiring board manufacturing method and printed wiring board

摘要

A printed wiring board (10C) manufacturing method includes weaving a glass fiber cloth (20) with warp (21) and weft (22) yarns such that the warp and weft yarns are visually distinguishable in at least a region of the board (10C). The glass fiber cloth (20) is impregnated with a resin to fabricate a substrate (30C). A copper foil is formed on at least one surface of the substrate to fabricate a core substrate (50). The copper foil is removed within the region on the core substrate to form an opening (521). A pitch between the warp yarns (21) or between the weft yarns (22) which are presented in the opening is detected. A pitch between a pair of differential wirings (40) to be patterned is determined based on the detected pitch between the warp yarns or between the weft yarns. The pair of differential wirings is patterned on the core substrate (50) in accordance with the determined pitch between the pair of differential wirings.