POLYIMIDE MULTILAYER FILM AND PREPARATION THEREOF

摘要

PURPOSE:To provide a multilayer film composed of soluble polyimide having a low dielectric constant and excellent in transparency, preparation thereof, and a polyimide acid solution to be used for it. CONSTITUTION:A polyimide multilayer film has a structure wherein a polyimide film is formed to a polyimide film soluble in an org. solvent and prepared by applying a polyamide acid solution using an org. solvent not dissolving polyimide on a polyimide film soluble in an org. solvent and curing the coated layer. The polyamide acid solution is prepared by dissolving polyamide acid being a precursor of polyimide soluble in a specific org. solvent in an org. solvent not dissolving polyimide. This polyimide multilayer film is useful for the preparation of a low light loss waveguide or a multilayer printed wring board of a low dielectric constant.