US Patent 7789977 Rolled copper foil and manufacturing method thereof

A rolled copper foil applied with a recrystallization annealing after a final cold rolling step and having a crystal grain alignment satisfying a ratio of [a]/[b]≧3, where [a] and [b] are normalized average intensities of a {111}Cu plane diffraction of a copper crystal by β-scanning at α=35° and 74°, respectively, in an X-ray diffraction pole figure measurement to a rolled surface is manufactured by controlling a total working ratio in the final cold rolling step before the recrystallization annealing to be 94% or more; and controlling a working ratio per one pass in the final cold rolling step to be 15 to 50%.