Method of manufacturing copper-polyimide substrate

Abstract

A method of manufacturing a copper-polyimide substrate, includes hydrophilicating the surface(s) of a polyimide film, applying a catalyst thereto, subjecting the film to electroless plating, heat-treating it in an inert atmosphere, and subjecting it to electroless copper plating or to electroless copper plating followed by electrolytic copper plating. The hydrophilication of the surface(s) of the polyimide film is effected with an aqueous solution containing a hydrazine hydrate and an alkali metal hydroxide or with an aqueous solution containing a permanganate and/or a hypochlorite, then a catalyst is applied to the surface(s) by an ordinary way, then the surface(s) is/are subjected to electroless plating with any one of nickel, cobalt nickel alloys or cobalt alloys to form a plated layer thereon having a thickness of from 0.01 to 0.1 .mu.m and having an impurity content of 10% by weight or less, and thereafter the resulting substrate is heat-treated in an inert atmosphere under the condition that the highest temperature that the substrate reaches falls within the range of from 350.degree. to 540.degree. C. and that the thermal load coefficient( D) to be obtained by the following numerical expression (1) falls within the range of from 0.3 to 3.5. ##EQU1## where ti indicates a desired time; and Ti indicates the temperature of the substrate itself at that time.