METHOD FOR PRODUCING FLEXIBLE WIRING BOARD

摘要

After first electroless plating layers (18b, 18c) and first conductive materials (16b, 16c) are grown sequentially on the surface of a first base film (11) having a reference conductive layer and a first surface conductive layer (13) disposed on the front and rear arranged surfaces thereof and provided with a first via penetrating the first surface conductive layer (13), a first coating conductive layer comprising the first electroless plating layers (18b, 18c), the first conductive materials (16b, 16c) and the first surface conductive layer (13) is etched to reduce the film thickness and then it is patterned to form a first wiring layer (20). Since the thin first coating conductive layer is etched and patterned, a desired pattern width can be obtained even when the first coating conductive layer is patterned by isotropic etching, e.g. wet etching.