Double-sided board and manufacture of the same

PURPOSE: To form conductive paths having excellent resistivity to chemicals and curl and bonding property to make conductive the copper foils in both surfaces in a board which is practically composed of copper foils and double- sided polyimide resin layer. CONSTITUTION: Copper foils 1, 1' are formed on both surfaces of an insulating resin layer providing a thermoplastic polyimide resin layer 3 between a couple of low linear expansion polyimide resin layers 2, 2' and a conductive path 4 is formed by providing a through hole only to the polyimide resin layer and then filling the hole with a metal substance. Excellent bonding characteristic can be realized by coating polyimide resin layer in the form of solution of polyimide precursor. COPYRIGHT: (C)1993,JPO&Japio