DOUBLE LAYER FLEXIBLE WIRING BOARD, AND METHOD FOR MANUFACTURING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide: a double layer flexible wiring board which is superior in folding endurance; a flexible wiring board; and manufacturing method for thereof.SOLUTION: A double layer flexible wiring board 6 comprises: a resin film base 1; and wiring lines formed by a metal laminate 7 provided on the surface of the resin film base 1 through no adhesive. The metal laminate 7 includes a backing metal layer 2 of a nickel alloy, and a copper layer 5 provided on the backing metal layer 2. According to the measurement by an electron beam backscattering diffraction method on the metal laminate 7, the ratio (OR/OR) of the part ORof 111-orientation crystal included in a range from the surface of the resin film base 1 to a depth of 0.4μm to the part ORof 001-orientation crystal is 7 or below. As to the copper layer 5, the (111) crystal orientation index is 1.2 or larger; and the difference d[(200)/(111)] between crystal orientation ratios [(200)/(111)] of the copper layer 5 obtained before and after execution of a folding endurance test (folding endurance test prescribed by JIS-C-5016-1994) is 0.03 or larger.