MULTILAYER POLYIMIDE FILM, FLEXIBLE METAL FOIL LAMINATE, METHOD FOR MANUFACTURING FLEXIBLE METAL FOIL LAMINATE, AND METHOD FOR MANUFACTURING RIGID-FLEXIBLE PRINTED WIRING BOARD

摘要

There is a problem such that cracks occur at locations of level differences in flexible printed wiring boards, in the hot pressing step, laser processing step for outer layer circuit formation, and desmearing treatment step in a process for manufacturing rigid-flexible printed wiring boards. The present invention solves this problem by using a multilayer polyimide film for which the maximum value of the loss elastic modulus coefficient derived from beta relaxation, as determined by dynamic viscoelasticity measurement, is observed at a temperature of 155 -185°C, such maximum value being 0.03-0.15.