FLEXIBLE PRINTED WIRING BOARD AND MANUFACTURING METHOD THEREOF

摘要

A flexible printed wiring board having a stable quality, not generating curls on a film even after circuit process on a conductor side, and a method of manufacturing such flexible printed wiring board are provided. The flexible printed wiring board is provided with a base layer, which is composed of at least one type of low thermal expansion polyimide resin, between a bottom layer contacting the conductor and a top layer on the opposite side to the conductor. The bottom layer and the top layer are composed of a thermoplastic polyimide rein having a larger thermal expansion coefficient than that of the base layer, and a thickness P1 of the bottom layer and a thickness P2 of the top layer satisfy a condition of P1<P2.