TWO-LAYER FLEXIBLE SUBSTRATE, METHOD FOR MANUFACTURING THE TWO-LAYER FLEXIBLE SUBSTRATE, AND FLEXIBLE PRINTED WIRING BOARD MANUFACTURED FROM THE TWO-LAYER FLEXIBLE SUBSTRATE

摘要

[PROBLEMS] To provide a two-layer flexible substrate which, even when allowed to stand at an elevated temperature of about 150°C, even at an elevated temperature of about 180°C, for a long period of time causes no significant lowering in adhesive strength between an insulating film and a copper layer (hereinafter often referred to as “peel strength”), particularly a two-layer flexible substrate suitable for fine pattern formation/COF mounting, and a method for manufacturing the two-layer flexible substrate. [MEANS FOR SOLVING PROBLEMS] A two-layer flexible substrate comprising an insulating film, a substrate metallic layer provided by a dry-type plating method directly on at least one side of the insulating film without interposing any adhesive agent, and a copper conductor layer having a desired layer thickness on the substrate metallic layer, characterized in that the substrate metallic layer is crystalline and is composed mainly of nickel-chromium or nickel-chromium-molybdenum in which 0.5 to 4.8 atomic% of a nitrogen atom has been dissolved.