TWO-LAYERED FLEXIBLE WIRING SUBSTRATE, AND FLEXIBLE WIRING BOARD USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a two-layered flexible wiring substrate and a flexible wiring board using the same, which are of excellent folding resistance. ! SOLUTION: A two-layered flexible wiring substrate has a multilayered structure of an underlying metal layer and a copper layer, wherein: the underlying metal layer is composed of nickel alloy; the copper layer is provided onto the surface of the underlying metal layer; and the two-layered flexible wiring substrate is provided on the surface of a polyimide film with no intervening adhesive. The two-layered flexible wiring substrate is characterized in that: the difference d[(200)/(111)] in the crystal orientation ratio [(200)/(111)] of the copper layer obtained before and after conducting the folding resistance test stipulated in JIS C-5016-1994 is 0.03 or greater; the crystal orientation ratio index in the (111) surface of the copper layer is 1.2 or greater; and the crystallite diameter thereof is 300 nm or greater. ! COPYRIGHT: (C)2015,JPO&INP