FLEXIBLE PRINTED-CIRCUIT BOARD AND ITS MANUFACTURE

摘要

PURPOSE:To enable dimensional change in an etching drying treatment process to be suppressed and dimensional stability to be improved by using a copolymerization polyimide film consisting of a repetition unit which is expressed by an expression (A) including a long-chain aromatic series diamine remaining group with a flexed group and that expressed by an expression (B) including an aromatic series diamine remaining group as an insulating material. CONSTITUTION:An aromatic series tetracarbonaciddianhydride (a) and one aromatic series diamine compound (b) are allowed to react within an organic polarity solvent using a more excessive mol than (a) and (b), a prepolymer with an acid anhydride at both edges is obtained, and then an aromatic series diamine compound (c) is added so that all aromatic series diamine [(a)+(c)] has a virtually equal mol as the aromatic series tetracarbon acid dianhydride in this copolymerization method, thus obtaining a copolymerizate where a length of a segment where either one repetition unit exists is constant within the copolymerizate molecule.