METHOD OF MANUFACTURING FLEXIBLE PRINTED WIRING BOARD

A method for manufacturing a flexible printed wiring board is provided to form a micro circuit pattern by using an etching liquid containing FeCl2 of 15-20w%, CrCl2 of 5-15w%, and HCl of 0.1-0.9w%. An insulation resin layer(1) and a conductive layer(2) are laminated to form a metal plate laminate. An etching resist layer(3) is formed on the conductive layer. The etching resist layer is cured into a predetermined pattern, when light is irradiated thereon. A non-cured portion of the conductive layer is removed to form an aperture(4). The conductive layer of a non-circuit portion is exposed through the aperture. The laminate is etched. An etching width in a sheet direction at a lowermost portion of the conductive layer is the same as a width of the aperture. A width of a circuit is reduced at an uppermost portion of the conductive layer.