FLEXIBLE PRINTED CIRCUIT BOARD AND METHOD FOR FORMING FINE PITCH THEREOF

摘要

PURPOSE: A flexible printed circuit board and a fine pitch formation method thereof are provided to improve the insulating property between wirings by forming an undercut at the lower end of the wirings. CONSTITUTION: A region in which a wiring(140) is formed among a base substrate(10) is etched. A conductive layer(90) is formed on the etched region. A photoresist film is formed on a substrate between the etched regions. The third photoresist film is formed on the front side of the flexible printed circuit board(165) to form a capping layer(160). The wirings are formed by forming the conductive layer on the etched regions higher than the substrate.