Rolled copper foil and manufacturing method thereof

Abstract

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%.

1 . A rolled copper foil made of a tough pitch copper or an oxygen-free copper, and applied with a recrystallization annealing after a final cold rolling step, and having a crystal grain alignment, wherein:
 in results obtained by an X-ray diffraction pole figure measurement with respect to a rolled surface of the rolled copper foil, the crystal grain alignment indicates a ratio of [a]/[b]≦3, where [a] and [b] are normalized average intensities of a {111} Cu  plane diffraction of a copper crystal, which are respectively obtained by β-scanning at α=35° and 74°.   
     
     
         2 . The rolled copper foil according to  claim 1 , wherein:
 in results obtained by an X-ray diffraction in-plane alignment measurement with respect to the rolled surface, an average of full width at half maximum of diffraction peaks (ave-FWHM {111} ) of the {111} Cu  plane in geometrical correlation with a {200} Cu  plane of the rolled surface is 10° or less.   
     
     
         3 . The rolled copper foil according to  claim 1 , wherein:
 in results obtained by an X-ray diffraction 2θ/θ measurement with respect to the rolled surface, 90% or more of diffraction peaks of the copper crystal occurs on a {200} Cu  plane; and   in results obtained by an X-ray diffraction rocking curve measurement with respect to the rolled surface, a full width at half maximum of the {200} Cu  plane diffraction peak (FWHM {200} ) is 10° or less.   
     
     
         4 . The rolled copper foil according to  claim 1 , wherein:
 in results obtained by an X-ray diffraction rocking curve measurement with respect to the rolled surface, a ratio between a full width at half maximum (FWHM {200} ) and an integration width (IW {200} ) of a {200} Cu  plane diffraction peak is “0.85≦IW {200} /FWHM {200} ≦1.15”; and   in results obtained by an X-ray diffraction in-plane alignment measurement with respect to the rolled surface, a ratio between a full width at half maximum (FWHM {111} ) and an integration width (IW {111} ) among fourfold symmetric diffraction peaks of the {111} Cu  plane in geometrical correlation with the {200} Cu  plane of the rolled surface is “0.85≦IW {111} /FWHM {111} ≦1.15”.   
     
     
         5 . The rolled copper foil according to  claim 1 , wherein:
 an average grain size of recrystallized grains observed on the rolled surface is 40 μm or more.   
     
     
         6 . The rolled copper foil according to  claim 1 , wherein:
 the rolled copper foil is made of a copper alloy comprising 0.001 to 0.009 mass % of Sn and a balance consisting of Cu and an inevitable impurity.   
     
     
         7 . The rolled copper foil according to  claim 1 , wherein:
 in results obtained by an X-ray diffraction 2θ/θ measurement with respect to the rolled surface, occupation ratio of {200} Cu  plane of the copper crystal is 90% or more; and   in results obtained by an X-ray diffraction rocking curve measurement with respect to the rolled surface, a full width at half maximum of the {200} Cu  plane diffraction peak (FWHM 200) ) is 10° or less.   
     
     
         8 . The rolled copper foil according to  claim 1 , wherein the rolled copper foil is made by a method, comprising:
 preparing an ingot made of the tough pitch copper or the oxygen-free copper;   conducting a hot rolling step;   conducting a plurality of times a step comprising the substeps of conducting a cold rolling step and then a process annealing step;   conducting a final cold rolling to produce the rolled copper foil of a predetermined thickness; and   subsequently conducting a recrystallization annealing;   wherein a total working ratio in the final cold rolling step before the recrystallization annealing is 94% or more; and   a working ratio per one pass in the final cold rolling step is 15 to 50%.   
     
     
         9 . The rolled copper foil according to  claim 7 , wherein:
 a working ratio of one pass in the final cold rolling step is “working ratio at first pass”≧“working ratio at second pass”≧“working ratio at third pass”; and   a working ratio at third or more passes in the final cold rolling step is 15 to 25%.   
     
     
         10 . The rolled copper foil according to  claim 6 , wherein the rolled copper foil is made by a method, comprising:
 preparing an ingot made of the copper alloy;   conducting a hot rolling step;   conducting a plurality of times a step comprising the substeps of conducting a cold rolling step and then a process annealing step;   conducting a final cold rolling step to produce the rolled copper foil of a predetermined thickness; and   subsequently conducting a recrystallization annealing;   wherein a total working ratio in the final cold rolling step before the recrystallization annealing is 94% or more; and   a working ratio per one pass in the final cold rolling step is 15 to 50%.   
     
     
         11 . The rolled copper foil according to  claim 9 , wherein:
 a working ratio of one pass in the final cold rolling step is “working ratio at first pass”≧“working ratio at second pass”≧“working ratio at third pass”; and   a working ratio at third or more passes in the final cold rolling step is 15 to 25%.