ROLLED COPPER FOIL, COPPER-CLAD LAMINATE, FLEXIBLE PRINTED WIRING BOARD AND ELECTRONIC DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a rolled copper foil not causing cracks in wiring even when used as wiring of a printed wiring board for a long time; a copper-clad laminate using the same; a flexible printed wiring board; and electronic devices.

SOLUTION: This rolled copper foil is such that: when the crystal grain boundary is defined as a site with ≥15° azimuth angle difference between a crystal orientation obtained by irradiating a measuring point of a crystal metal structure with electron beams and a crystal orientation obtained by irradiating a plurality of adjacent measuring points positioned around the measuring point while being apart by 0.5 μm with electron beams, the length of the crystal grain boundary measured after annealing at 400°C for 1 hour is 95 cm/mm2or shorter.

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