Polyimide resin film

摘要: A resin film for mainly making a flexible printed circuit board and method of the film. When copper foil (2) is etched in specified pattern after heat-bonded to (1) order make board, said undergoes dimensional variation. For purpose reducing such variation, ratio (a/b) linear expansion coefficient (a) mechanical feeding direction (MD direction) that (b) (TD perpendicular one set at 0.2 or more but less than 1.0, 0.4 2.0 x 10-5 °C-1. As film, polyimide including 90 % identity period represented by general formula used. Further, stretched 1.0 1.5 times 0.5 0.99 direction.