JP5320638B2 - Rolled copper foil and method for producing the same - Google Patents

Abstract

A rolled copper foil, according to the present invention, obtained after a final cold rolling step but before recrystallization annealing includes a group of crystal grains which exhibits four-fold symmetry in results obtained by X-ray diffraction (XRD) pole figure measurement with respect to a rolled surface. In the XRD pole figure measurement, at least four peaks of a {220}Cu plane diffraction of a copper crystal due to the group of crystal grains exhibiting the four-fold symmetry, which is obtained during beta axis scanning with an alpha angle set to 45 DEG , appear at intervals of 90 DEG +-5 DEG along the beta angle.

Description

  The present invention relates to a rolled copper foil, and more particularly to a rolled copper foil having excellent bending characteristics suitable for a flexible wiring member such as a flexible printed wiring board.

  A flexible printed circuit (hereinafter referred to as “FPC”) has a high degree of freedom in mounting on an electronic device or the like because of its thin thickness and excellent flexibility. For this reason, the folding parts of foldable mobile phones, movable parts such as digital cameras and printer heads, and disk-related equipment such as HDD (Hard Disk Drive), DVD (Digital Versatile Disc), and CD (Compact Disk) are now available. FPC is widely used for wiring of movable parts.

  As the FPC conductor, pure copper foil or copper alloy foil (hereinafter simply referred to as “copper foil”) subjected to various surface treatments is generally used. Copper foils are roughly classified into electrolytic copper foils and rolled copper foils depending on the manufacturing method. FPC is used as a wiring material for parts that can be repeatedly moved as described above, and therefore excellent bending characteristics (for example, bending characteristics of 1 million times or more) are required, and rolled copper foil is used as the copper foil. There are many.

  In general, rolled copper foil is manufactured by hot rolling an ingot of tough pitch copper (JIS H3100 C1100) or oxygen-free copper (JIS H3100 C1020), which is a raw material, and then cold rolling to a predetermined thickness. It is performed by repeatedly performing intermediate annealing. The thickness required for the rolled copper foil for FPC is usually 50 μm or less, but recently, it has a tendency to be further reduced to a dozen μm or less.

  The manufacturing process of FPC is roughly as follows: "Copper for FPC and base film (base material) made of resin such as polyimide are bonded to form CCL (Copper Claded Laminate) (CCL process)" , “A step of forming a circuit wiring on the CCL by a technique such as etching”, “a step of performing a surface treatment for protecting the wiring on the circuit”, and the like. In the CCL process, after laminating the copper foil and the base material via an adhesive, the adhesive was cured and adhered by heat treatment (three-layer CCL), and the surface treatment was applied without using the adhesive. There are two types of methods in which a copper foil is directly bonded to a substrate and then integrated by heating and pressing (two-layer CCL).

  Here, in the manufacturing process of the FPC, a copper foil that has been cold-rolled (hardened after work hardening) is often used from the viewpoint of ease of manufacturing. When the copper foil is in an annealed (softened) state, the copper foil is likely to be deformed (for example, stretched, wrinkled, broken, etc.) during the cutting of the copper foil or the lamination with the base material, resulting in a defective product. Because.

  On the other hand, the bending characteristics of the copper foil are remarkably improved as compared with the state after the rolling process by performing recrystallization annealing. Therefore, a manufacturing method that also serves as recrystallization annealing of the copper foil is generally selected in the heat treatment for bringing the base material and the copper foil into close contact and integration in the above-described CCL process. The heat treatment conditions at this time are 180 to 300 ° C. for 1 to 60 minutes (typically 200 ° C. for 30 minutes), and the copper foil is tempered into a recrystallized structure.

In order to improve the bending characteristics of FPC, it is effective to increase the bending characteristics of the rolled copper foil as the material. In general, it is known that the bending characteristics of a copper foil after recrystallization annealing improve as the cubic texture develops. Note that “cubic texture development” generally referred to only means that the occupancy of the {200} _Cu surface is high (for example, 85% or more) on the rolled surface.

Conventionally, the following has been reported as a rolled copper foil having excellent bending characteristics and a method for producing the same. A method of developing a cubic texture by increasing the total degree of work in the final cold rolling process (for example, 90% or more), and a copper foil that defines the degree of development of the cubic texture after recrystallization annealing (for example, rolling) A copper foil having a strength of (200) plane determined by X-ray diffraction of the plane greater than 20 times the strength of (200) plane determined by powder X-ray diffraction. A method in which a cube texture is developed during intermediate annealing before the final cold rolling step, and the total degree of work in the final cold rolling step is set to 93% or more to further develop the cube texture after recrystallization. A copper foil that defines the ratio of through crystal grains in the thickness direction of the copper foil plate (for example, a copper foil having a cross-sectional area ratio of 40% or more being through crystal grains). A copper foil whose softening temperature is controlled by adding a trace amount of additive elements (for example, a copper foil controlled to a semi-softening temperature of 120 to 150 ° C.). A copper foil having a defined twin boundary length (for example, a copper foil having a twin boundary exceeding 5 μm in length and having a total length of 20 mm or less per 1 mm ² area). Copper foils whose recrystallized structure is controlled by adding trace elements (for example, copper foils with 0.01 to 0.2% by mass of Sn added, controlled to an average crystal grain size of 5 μm or less and a maximum crystal grain size of 15 μm or less), etc. Have been reported (for example, see Patent Documents 1 to 7).

JP 2001-262296 A Japanese Patent No. 3009383 JP 2001-323354 A JP 2006-117777 A JP 2000-212661 A JP 2000-256765 A JP 2005-68484 A

  As described above, it has been reported in the prior art that the higher the total degree of work in the final cold rolling step, the more the cubic texture of the rolled copper foil develops after recrystallization annealing and the flexibility increases. However, in cold rolling, the higher the total degree of work, the harder the material (copper foil) by work hardening, so the control of the degree of work per pass becomes difficult and the production efficiency of the rolled copper foil decreases. There is. Specifically, when the total workability of cold rolling is about 90% or more (particularly 93% or more), control of the workability per pass and the rolling work itself become rapidly difficult.

  On the other hand, in recent years, with the progress of downsizing, high integration (high density mounting), high performance, etc. of electronic devices, demands for higher bending characteristics than ever are increasing. Since the bending characteristics of the FPC are substantially determined by that of the copper foil, it is essential to further improve the bending characteristics of the copper foil in order to satisfy the requirements. In addition, there is an increasing demand for cost reduction of electronic components.

  Accordingly, an object of the present invention is to provide a rolled copper foil which is suitable for a flexible wiring member such as a flexible printed wiring board (FPC) and has excellent bending characteristics. Furthermore, a manufacturing method capable of stably and efficiently producing a rolled copper foil having high bending characteristics (ie, at low cost) without performing a high total workability as in the past in the final cold rolling process. It is to provide.

  The present inventors have made detailed metallographic studies on rolled copper foil, rolled copper foil after dough annealing and before the final cold rolling step, and rolling before recrystallization annealing after the final cold rolling step It has been found that the orientation and orientation state of crystal grains in the copper foil have a specific correlation between the crystal grain orientation state after recrystallization annealing and the bending characteristics of the copper foil. Further, the present invention has been completed based on the finding that the phenomenon seems to be a phenomenon different from the previously considered principle (details will be described later).

In order to achieve the above object, the present invention is a rolled copper foil after the final cold rolling process and before recrystallization annealing, comprising a copper foil in which a cubic texture develops by recrystallization annealing, and is based on the rolling surface. As a result of X-ray diffraction pole figure measurement, the { 220 } _Cu plane diffraction peak of copper crystal obtained by β scan at α angle = 45 ° of pole figure measurement exists every 90 ± 5 ° of β angle Thus, there is provided a rolled copper foil characterized by the presence of crystal grains exhibiting 4-fold symmetry.

Moreover, in order to achieve the above object, the present invention provides the rolled copper foil according to the present invention,
Provided is a rolled copper foil characterized in that the diffraction peak exhibiting the 4-fold symmetry has a diffraction intensity of 1.5 times or more with respect to the minimum intensity of {220} _Cu plane diffraction of the copper crystal obtained by the β scan. To do.

Moreover, in order to achieve the above object, the present invention provides the rolled copper foil according to the present invention,
The result obtained by X-ray diffraction pole figure measurement based on the rolling surface, and the standard of {220} _Cu plane diffraction peak of copper crystal obtained by β scanning at each α angle with the α angle of the pole figure measurement as the horizontal axis When the normalized intensity is expressed as a graph, the normalized strength maximum P exists between α = 25 to 35 °, and the normalized strength maximum Q between α = 40 to 50 °. The normalized strength monotonically increases between α = 85 and 90 °, and the maximum value P, the maximum value Q, and the normalized strength value R at α = 90 ° are expressed as “ Provided is a rolled copper foil characterized in that Q ≦ P ≦ R ”.

Moreover, in order to achieve the above object, the present invention provides the rolled copper foil according to the present invention,
Provided is a rolled copper foil characterized in that the intensity of a diffraction peak of a copper crystal is “I _{{200} Cu} ≧ I _{{220} Cu} ” as a result of X-ray diffraction 2θ / θ measurement on the rolled surface To do.

Further, in order to achieve the above object, the present invention is a rolled copper foil that has been subjected to recrystallization annealing after the final cold rolling step, and is composed of a copper foil in which a cubic texture is developed by recrystallization annealing, and is rolled. The ratio [A] of the cube texture calculated from the X-ray diffraction 2θ / θ measurement to the surface, and the out-of-plane orientation ratio [B] calculated from the X-ray diffraction rocking curve measurement for the crystal grains of the cube texture; The product of the cubic textured grains and the in-plane orientation ratio [C] calculated from the X-ray diffraction pole figure measurement based on the rolling surface is “[A] × [B] × [C] ≧ Provided is a rolled copper foil characterized by being "0.5".

In order to achieve the above object, the present invention is a rolled copper foil made of a copper foil whose cubic texture is developed by recrystallization annealing, and after the final cold rolling step, before the recrystallization annealing. The results obtained by X-ray diffraction pole figure measurement with reference to the rolling surface in Fig. 6 show that the { 220 } _Cu plane diffraction peak of the copper crystal obtained by β scan at the α angle = 45 ° of the pole figure measurement is 90 ± A method for producing a rolled copper foil in which crystal grains having a 4-fold symmetry are present every 5 °, and in the rolling pass after the second pass in the final cold rolling step, processing of the immediately preceding rolling pass One or more rolling passes having a working degree 1.1 times larger than the degree are included, and the last pass in the final cold rolling step or the pass immediately before the final pass is the largest one in the second and subsequent passes. With a degree of processing To provide a method of manufacturing a rolled copper foil, wherein the total working ratio in rolling process is less than 80% to 90%.

In order to achieve the above object, the present invention is a rolled copper foil made of a copper foil whose cubic texture is developed by recrystallization annealing, and after the final cold rolling step, before the recrystallization annealing. The results obtained by X-ray diffraction pole figure measurement with reference to the rolling surface in Fig. 6 show that the { 220 } _Cu plane diffraction peak of the copper crystal obtained by β scan at the α angle = 45 ° of the pole figure measurement is 90 ± There is a crystal grain that exists every 5 ° and exhibits 4-fold symmetry, and the standard of { 220 } _Cu plane diffraction peak of copper crystal obtained by β scan at each α angle with α angle of pole figure measurement as horizontal axis When the normalized intensity is expressed as a graph, the normalized strength maximum P exists between α = 25 to 35 °, and the normalized strength maximum Q between α = 40 to 50 °. The normalized strength monotonously increases between α = 85 and 90 °, and the maximum value P and the maximum Q is a method for producing a rolled copper foil in which the normalized strength value R at α = 90 ° is “Q ≦ P ≦ R”, and rolling before dough annealing and before the final cold rolling step { 220 } _Cu surface diffraction of copper crystals obtained by X-ray diffraction pole figure measurement based on the rolled surface in copper foil, with the α angle of the pole figure measurement as the horizontal axis and β scan at each α angle When the normalized intensity of the peak is shown as a graph on the vertical axis, there is a maximum value Q of the normalized intensity between α = 40 and 50 °, and the normalized intensity of the peak between α = 20 and 40 °. A rolled copper foil in which a minimum value S exists and the ratio between the maximum value Q and the minimum value S is “2 ≦ Q / S ≦ 3” is used as an annealed fabric, and the total workability in the final cold rolling step Is 80% or more and less than 93%.

  ADVANTAGE OF THE INVENTION According to this invention, it is suitable for flexible wiring members, such as a flexible printed wiring board (FPC), and can provide the rolled copper foil which has the outstanding bending characteristic. Furthermore, the manufacturing method which manufactures the rolled copper foil which has a high bending characteristic stably and efficiently (namely, low cost) can be provided.

A schematic diagram showing main crystal planes of a copper crystal related to the present invention is shown in FIG. Since the crystal structure of copper is cubic, the angle between the {200} _Cu face and the {220} _Cu face is 45 °. Note that {} represents an equivalent surface (see FIG. 1).

  FIG. 2 is a schematic diagram showing a relationship among incident X-rays, detectors, samples, and scanning axes in X-ray diffraction (hereinafter sometimes referred to as XRD). Hereafter, the evaluation method regarding the crystal grain orientation state of the rolled copper foil by XRD is demonstrated using FIG. Note that the three scanning axes in FIG. 2 are generally called a sample axis, an α axis having a θ axis, and a β axis being an in-plane rotation axis. Further, all X-ray diffraction in the present invention is based on Cu Kα rays.

  A measurement method in which a sample and a detector are scanned with respect to incident X-rays along the θ axis, the scanning angle of the sample is scanned with θ, and the scanning angle of the detector with 2θ is called 2θ / θ measurement. Based on the intensity of the diffraction peak by 2θ / θ measurement, it is possible to evaluate which crystal plane is dominant on the sample surface (rolled surface in the present invention) of a rolled copper foil that is a polycrystalline body.

Focusing on a certain diffractive surface {hkl} _Cu , the rocking curve is a measurement method that scans only the sample with the θ-axis relative to the 2θ value of the focused {hkl} _Cu surface (with the detector scanning angle 2θ fixed) This is called measurement. The degree of orientation of the {hkl} _Cu plane in the direction perpendicular to the rolling plane can be evaluated by the half width or integral width of the {hkl} _Cu plane peak obtained by this measurement. At this time, it can be said that the smaller the value of the half width or the integral width, the better the crystal orientation in the direction perpendicular to the rolling surface (hereinafter referred to as “crystal orientation in the direction perpendicular to the rolling surface” as “out-of-plane orientation”). Called). The half width is defined as the peak width at half the maximum intensity of the diffraction peak, and the integral width is defined as the integral intensity of the diffraction peak divided by the maximum intensity of the diffraction peak.

One of evaluation methods using the characteristics of pole figure measurement is in-plane orientation measurement. This is because when the angle between the {hkl} _Cu plane of interest and the crystal plane {h'k'l '} _Cu geometrically corresponding to the {hkl} _Cu plane is α ′, “α = 90− Scan the α axis so that it becomes “α ′” (tilt the sample), and fix the sample to the β axis with respect to the 2θ value of the {h′k′l ′} _Cu surface (fixing the scanning angle 2θ of the detector) This is a measurement method of scanning (in-plane rotation (rotation) from 0 to 360 °). 'In _Cu surface half width or integration width of a peak, {h'k'l {h'k'l}' by this measure} _Cu plane geometrically corresponding {hkl} _Cu plane of the rolling plane 2 The degree of orientation in the axial direction can be evaluated. At this time, as described above, it can be said that the smaller the half width or integral width of the diffraction peak, the better the crystal orientation in the in-rolling plane direction (hereinafter referred to as “crystalline orientation in the in-rolling plane direction”). Is referred to as “in-plane orientation”). In the XRD pole figure measurement of the present invention, the direction perpendicular to the sample surface is defined as α = 90 °, which is used as a measurement reference. The pole figure measurement includes a reflection method (α = 15 to 90 °) and a transmission method (α = 0 to 15 °). The pole figure measurement in the present invention is performed by the reflection method (α = 15 to 90 °). ) Only the measurement is considered.

[First embodiment of the present invention]
(In-plane orientation measurement)
The rolled copper foil in the present embodiment is a rolled copper foil after the final cold rolling process and before recrystallization annealing, and is a result obtained by X-ray diffraction pole figure measurement based on the rolled surface. A {220} _Cu plane diffraction peak of a copper crystal obtained by β scanning at a measurement α angle = 45 ° exists at every 90 ± 5 ° of the β angle and exhibits fourfold symmetry. For example, when the rolling direction of copper foil is β = 0 ° in the pole figure measurement, the centers of the four-fold symmetric diffraction peaks are β≈0 °, 90 °, 180 °, 270 °, (360 °), respectively. .

In the above in-plane orientation measurement results, when the {220} _Cu plane diffraction peak does not show the 4-fold symmetry every 90 ± 5 °, a rolled copper foil having high bending properties can be obtained even if recrystallization annealing is performed. Absent. Therefore, it is defined as described above. It should be noted that the {220} _Cu plane diffraction peak of the copper crystal obtained by β scanning at the α angle = 45 ° of the pole figure measurement shows the 4-fold symmetry every 90 ± 5 ° indicates that the {220} _Cu plane The {200} _Cu plane, which forms an angle of 45 ° with respect to the crystal geometry, means that the in-plane orientation is in the rolled plane of the copper foil. In addition, the diffraction peak of the 4-fold symmetry is 1.5 times or more than the minimum intensity of {220} _Cu- plane diffraction, where each diffraction peak intensity is obtained by β-axis scanning (in-plane rotation from 0 to 360 °). It is desirable to have

[Second Embodiment of the Present Invention]
(Standardized strength)
The rolled copper foil in the present embodiment is a rolled copper foil after the final cold rolling process and before recrystallization annealing, and is a result obtained by X-ray diffraction pole figure measurement based on the rolled surface. When graphed with the normalized intensity of the {220} _Cu- plane diffraction peak of the copper crystal obtained by β scanning at each α angle as the abscissa and α = 25 to 35 ° There is a maximum value P of the normalized strength, and there is a maximum value Q of the standardized strength between α = 40 to 50 °, and the normalized strength increases monotonously between α = 85 to 90 °. The maximum value P, the maximum value Q, and the normalized strength value R at α = 90 ° satisfy “Q ≦ P ≦ R”. As a result of the above XRD pole figure measurement, the normalized intensity of the {220} _Cu plane diffraction peak is a maximum value P of α = 25 to 35 °, a maximum value Q of α = 40 to 50 °, and α = 85 to 90 °. If the maximum value P, the maximum value Q, and the normalized strength value R at α = 90 ° do not show the relationship of “Q ≦ P ≦ R”, the recrystallization annealing is not performed. Even if applied, a rolled copper foil having high bending properties cannot be obtained. Therefore, it is defined as described above.

Note that the normalized intensity R _c is a count number obtained by averaging predetermined {hkl} _Cu diffraction peak intensities by β-axis scanning (in-plane rotation axis scanning) at each α angle in the XRD pole figure measurement. It can be calculated by an equation (refer to the following document for details). The normalization calculation is usually performed by a computer.
R _c = I _c / I _std
here,
I _c : correction intensity (background correction, absorption correction)
I _std : strength for normalization obtained by calculation.
(Literature name) “RAD system application software texture analysis program instruction manual (manual number: MJ201RE)”, Rigaku Corporation, p. 22-23.
(Literature name) “CN9258E101 RINT2000 Series Application Software Positive Point Instruction Manual (manual number: MJ10102A01)” Rigaku Corporation, p. 8-10.
The reason for using the standardized XRD peak intensity is to allow comparison without the influence of differences in conditions such as tube voltage and tube current during XRD measurement. Disappear).

[Third embodiment of the present invention]
(2θ / θ measurement)
The rolled copper foil in the present embodiment is a result obtained by X-ray diffraction 2θ / θ measurement on the rolled surface in the state after the final cold rolling process and before recrystallization annealing, and the intensity of the diffraction peak of the copper crystal. I is characterized by “I _{{200} Cu} ≧ I _{{220} Cu} ”.

As described above, in the rolled copper foil according to the present invention, the {200} _Cu plane is oriented with the rolled surface of the copper foil in the state after the final cold rolling step and before the recrystallization annealing. This means that a considerable amount of {200} _Cu face-oriented crystal grains are present on the rolled surface of the copper foil which is a polycrystal. FIG. 3 is an example of the result of X-ray diffraction 2θ / θ measurement performed on the rolled surface in the rolled copper foil according to the present invention after the final cold rolling step and before recrystallization annealing. .

As apparent from FIG. 3, the diffraction intensity of the rolled surface is {200} _Cu surface is strong, indicating that there exists a number {200} _Cu plane oriented crystal grains. If the {200} _Cu surface is not strongly oriented on the rolled surface of the copper foil, a rolled copper foil having high bending properties cannot be obtained even if recrystallization annealing is performed. Therefore, it is defined as described above.

[Fourth Embodiment of the Present Invention]
(Total orientation ratio)
The rolled copper foil in the present embodiment is a rolled copper foil after recrystallization annealing after the final cold rolling step, and the ratio of the cube texture calculated from the X-ray diffraction 2θ / θ measurement with respect to the rolled surface [A], the out-of-plane orientation ratio calculated from the X-ray diffraction rocking curve measurement for the crystal grains of the cubic texture, and the X-ray diffraction of the cubic texture crystals based on the rolling surface The product of the in-plane orientation ratio [C] calculated from the pole figure measurement is “[A] × [B] × [C] ≧ 0.5”. In the present invention, [A] × [B] × [C] is defined as the total orientation ratio. When the total orientation ratio is less than 0.5 ([A] × [B] × [C] <0.5), high bending characteristics cannot be obtained. Therefore, the overall orientation ratio is set to 0.5 or more. More desirably, it is 0.55 or more, and more desirably 0.6 or more.

  Next, the ratio [A] of the cube texture, the out-of-plane orientation ratio [B] of the cube texture, and the in-plane orientation ratio [C] of the cube texture will be described.

Cubic texture ratio [A] is the result of X-ray diffraction 2θ / θ measurement on the rolled surface of the rolled copper foil that has been recrystallized and annealed after the final cold rolling step to represent the cubic texture {200} _The ratio of the _Cu plane diffraction peak to the total diffraction peak is defined as calculated by the following formula.
Cubic texture ratio [A] = I _{{200} Cu} / (I _{{111} Cu} + I _{{200} Cu} + I _{{220} Cu} + I _{{311} Cu} )
here,
I _{{111} Cu} : Diffraction peak intensity of {111} _Cu surface
I _{{200} Cu} : {200} Diffraction peak intensity on _Cu surface
I _{{220} Cu} : {220} Diffraction peak intensity of _Cu plane
I _{{311} Cu} : {311} The diffraction peak intensity on the _Cu surface.

The out-of-plane orientation ratio [B] of the cube texture is measured by measuring the X-ray diffraction rocking curve of the {200} _Cu surface on the rolled surface of the rolled copper foil subjected to recrystallization annealing after the final cold rolling step. {200} The ratio of the half-value width and the integral width of the _Cu plane diffraction peak is defined as calculated by the following equation.
Out-of-plane orientation ratio of cubic texture [B] = Δθ _FWHM / Δθ _IW
In addition,
Δθ _FWHM : {200} Peak width at half the maximum intensity of the _Cu plane diffraction peak Δθ _IW : {200} The integrated intensity of the _Cu plane diffraction peak is divided by the maximum intensity of the diffraction peak.

The in-plane orientation ratio [C] of the cubic texture is the X of the {220} _Cu surface at an α angle = 45 ° with respect to the rolled surface of the rolled copper foil subjected to recrystallization annealing after the final cold rolling step. A line diffraction pole figure measurement was performed, and the ratio of the half width and the integral width of any one of the four-fold symmetrical {220} _Cu surface diffraction peaks obtained by β scanning was calculated by the following equation: Define.
Out-of-plane orientation ratio of cubic texture [C] = Δβ _FWHM / Δβ _IW
In addition,
Δβ _FWHM : {220} Peak width at half the maximum intensity of the _Cu- plane diffraction peak Δβ _IW : {220} The integrated intensity of the _Cu- plane diffraction peak is divided by the maximum intensity of the diffraction peak.

  Here, the meaning of taking the ratio of the half width of the diffraction peak to the integral width in the out-of-plane orientation ratio [B] and the in-plane orientation ratio [C] will be described. FIG. 4 is a schematic diagram showing the relationship between the quality of crystal orientation and the half-value width and integral width of a diffraction peak. When rocking curve measurement or in-plane orientation measurement is performed on a rolled copper foil with low crystal orientation, as shown in FIG. 4 (a), the vicinity of the peak center is relatively sharp but the tail portion is large (wide base). ) A diffraction peak shape is easily obtained. On the other hand, when rocking curve measurement or in-plane orientation measurement is performed on a rolled copper foil with high crystal orientation, a diffraction peak shape concentrated near the peak center as shown in FIG. 4B is obtained.

  When the half width and the integral width are evaluated for these diffraction peaks, respectively, when the crystal orientation is low (a), a large difference occurs between the half width and the integral width, and the crystal orientation is high (b). In the case of, it can be seen that the difference between the half width and the integral width becomes small. Such a difference is considered to be caused by the size of the tail portion in the diffraction peak shape (the size of the tail portion in the diffraction peak shape). Therefore, by taking the ratio of the half width and integral width of the diffraction peak, it is possible to more clearly determine the superiority or inferiority of the crystal orientation of the rolled copper foil than comparing the half width and integral width individually. become.

[Method for producing rolled copper foil]
Next, the manufacturing method of the rolled copper foil which concerns on this invention is demonstrated, referring FIG. FIG. 5 is a flowchart showing an example of a process for producing a rolled copper foil according to the present invention.

  First, ingots (ingots) such as tough pitch copper (JIS H3100 C1100) and oxygen-free copper (JIS H3100 C1020) as raw materials are prepared (step a). Next, the hot rolling process (process b) which performs hot rolling is performed. After the hot rolling process, a copper called “dough” is obtained by appropriately repeating a cold rolling process (process c) for performing cold rolling and an intermediate annealing process (process d) for relaxing work hardening by cold rolling. Articles are manufactured. Next, a dough annealing step (step d ′) is performed. In the dough annealing process, it is desirable that the previous processing strain is sufficiently relaxed (for example, substantially complete annealing).

  Thereafter, the annealed “fabric” (referred to as “annealed fabric”) is subjected to a final cold rolling step (sometimes referred to as “step e” or “finish rolling step”), and rolled copper having a predetermined thickness. A foil is produced. The rolled copper foil after the final cold rolling process is subjected to surface treatment or the like as necessary (process f) and supplied to the FPC manufacturing process (process g). As described above, the recrystallization annealing (step g ′) is often performed in the step g (for example, the CCL step). In the present invention, the “final cold rolling step” means the step e, and the “recrystallization annealing” step g ′ means that performed in the step g.

Here, one of the methods for producing a rolled copper foil according to the present invention has a degree of processing that is 1.1 times greater than the degree of processing of the immediately preceding rolling pass in the second and subsequent passes in the final cold rolling step. One or more rolling passes are included. Thereby, in the final stage of the cold rolling process, the formation of {220} _Cu plane-oriented rolling texture can be strengthened, and a cubic structure seed crystal can be actively formed in the rolling texture. And it is thought that the seed crystal of this cube structure has contributed to the high orientation growth of the cube texture by recrystallization annealing (details are mentioned later).

  More preferably, “a rolling pass having a processing degree 1.15 times or more larger than the processing degree of the immediately preceding rolling pass is included”, and more preferably “1.2 times or more the processing degree of the immediately preceding rolling pass” “One or more rolling passes having a large degree of work are included”. In a “rolling pass having a degree of work smaller than 1.1 times” deviating from the above definition, it is difficult to form a cubic structure seed crystal in the rolling texture.

  In addition, it is desirable that the final pass or the pass immediately before the final pass in the final cold rolling process has the highest degree of processing per pass in the second and subsequent passes. Thereby, it can suppress that the seed crystal of the cube structure | tissue formed in the rolling texture rotates to the other position with progress of a rolling process (details are mentioned later). In addition to reducing the total number of passes in the rolling process by making the total workability in the final cold rolling process 80% or more and less than 90%, it is difficult to control the rolling process due to excessive work hardening. This can contribute to a reduction in manufacturing costs. By the manufacturing method of the present invention having the above-described features, it is possible to achieve both high bending characteristics and low cost in the rolled copper foil.

Moreover, the other manufacturing method of the rolled copper foil which concerns on this invention replaced with said manufacturing method is a manufacturing method which adjusts an annealing material | dough as follows by controlling a material | dough annealing process (process d ') at least. . In the rolled copper foil (annealed dough) after the dough annealing (step d ′) and before the final cold rolling step (step e), the results are obtained by X-ray diffraction pole figure measurement based on the rolling surface. The graph shows the normalized intensity of the {220} _Cu plane diffraction peak of the copper crystal obtained by β scanning at each α angle as the abscissa and α = 40 to 50 °. There is a maximum value Q of standardized strength, there is a minimum value S of standardized strength between α = 20 to 40 °, and the ratio of the maximum value Q to the minimum value S is “2 ≦ Q / S It is characterized by using a rolled copper foil of ≦ 3 ”as an annealed material for the final cold rolling process. Furthermore, the final cold rolling step (step e) is performed on such an annealed material so that the total degree of processing becomes 80% or more and less than 93%. In addition, as material | dough annealing conditions, the conditions hold | maintained for 1 to 30 minutes at 600 degreeC or more and less than 700 degreeC (actual temperature of copper foil) are preferable, for example. A more preferable temperature is 650 ° C. or higher and lower than 700 ° C.

As a result, the pole figure measurement is a result obtained by the X-ray diffraction pole figure measurement based on the rolling surface in the rolled copper foil after the final cold rolling process (process e) and before the recrystallization annealing (process g ′). {220} _Cu plane diffraction peak of copper crystal obtained by β scan at α angle = 45 ° of the crystal exists at least every 90 ± 5 ° of β angle, and there is a crystal grain showing 4-fold symmetry. When the graph shows the normalized intensity of the {220} _Cu plane diffraction peak of copper crystals obtained by β-scanning with the α angle of the pole figure measurement as the horizontal axis, the standard is between α = 25 to 35 °. There is a maximum value P of normalized strength, the maximum value Q of standardized strength remains between α = 40-50 °, and the normalized strength monotonically increases between α = 85-90 °. The rolled copper foil according to the present invention in which the value P, the maximum value Q, and the normalized strength value R at α = 90 ° are “Q ≦ P ≦ R” is obtained.

As described above, the {220} _Cu plane and the {200} _Cu plane of the copper crystal have a geometrical relationship of 45 ° (the angle between both crystal planes is 45 °). Therefore, the maximum value Q of the normalized strength between α = 40 and 50 ° is related to the degree to which the crystal grains of the {200} _Cu plane are in-plane oriented on the rolled surface of the rolled copper foil. Conceivable. In other words, the {200} _Cu- plane-oriented and in-plane-oriented crystals present on the rolling surface in the dough after the dough annealing (step d ′) and before the final cold rolling step (step e) are finally cold rolled. The feature of the present invention resides in that it remains after the process (process e) to the extent that “Q ≦ P ≦ R” is satisfied.

  In addition, by setting the total workability in the final cold rolling process to 80% or more and less than 93%, the total number of passes in the rolling process can be reduced compared to conventional high-workability rolled copper foil. Thus, difficulty in controlling the rolling process due to excessive work hardening can be avoided, and the load on the manufacturing facility can be reduced and the manufacturing cost can be reduced. With the production method of the present invention having such characteristics, it is possible to achieve both high bending characteristics and low cost in the rolled copper foil.

(Consideration of mechanism for high bending characteristics)
Below, the mechanism of the high bending characteristic of the rolled copper foil which concerns on embodiment of this invention is demonstrated.

  When stress is applied to the metal crystal, the movement of dislocations in the crystal tends to occur along the slip plane of the crystal. However, crystal grain boundaries are generally an obstacle to dislocation movement. In a rolled copper foil that is a polycrystalline body, when dislocations accumulate at a grain boundary or the like due to a bending motion, cracks are likely to occur at the accumulation location, which is considered to cause so-called metal fatigue. In other words, if it is possible to suppress the accumulation of dislocations in the metal polycrystal, it is expected that the bending characteristics will be improved.

The rolled copper foil according to the embodiment of the present invention can control the cubic texture after the recrystallization annealing by controlling the annealing dough and / or the crystal grain orientation state after the final cold rolling process. It is shown that. Recrystallized to obtain a cubic texture in which the orientation of the {111} _Cu plane (that is, aligning the slip direction), which is the slip plane peculiar to the face-centered cubic structure of copper crystals, is well controlled across the grain boundaries. If it is possible, the probability that the dislocations will cross and slip during the bending motion increases, and as a result, it is considered that high bending characteristics can be obtained. That is, the key point is how to form a cubic texture in which crystal grains are three-dimensionally oriented (having a high overall orientation ratio).

On the other hand, the stress applied to the object at the time of rolling can be divided into “compressive stress component” and “tensile stress component” for the object. Moreover, in the cold rolling process with respect to copper foil, the copper crystal in copper foil raise | generates a rotation phenomenon with the stress at the time of a rolling process, and forms a rolling texture with progress of a process. At this time, the rotation direction of the crystal depending on the stress direction (orientation oriented on the rolling surface) is generally {220} _Cu surface in the case of compressive stress and {311} _Cu surface or {211} _{Cu in} the case of tensile stress. Surface. It has been considered that the accumulation of processing strains accompanying these rotational phenomena becomes the driving force for forming the cube texture during recrystallization.

In the conventional rolled copper foil, from the above viewpoint, the total workability in the final cold rolling process is set high (for example, 93% or more), and the {220} _Cu plane orientation (rolling assembly) is set by increasing the compressive stress. It was intended to increase the accumulation of processing strains. In addition, as mentioned above, the cubic texture is focused on only the fact that the {200} _Cu plane occupancy is high on the rolled surface (one-dimensional orientation in the direction perpendicular to the rolled surface). No particular consideration has been given to the state (that is, the three-dimensional orientation between crystal grains). Moreover, paying attention only to the total workability in the final cold rolling process, no special consideration has been given to the workability per pass. However, since the material (copper foil) becomes harder due to work hardening as the rolling process progresses, it seems that the degree of processing per pass decreases as the rolling process progresses.

However, in such a pass schedule, a part of the crystal grains once {220} _Cu- plane oriented by a high workability pass (rolling pass having a high workability per pass) is obtained by a subsequent low workability pass. It is thought that this leads to rotation to {311} _Cu plane orientation or {211} _Cu plane orientation. This is because the “compressive stress component” predominates in a rolling pass with a high degree of work per pass, and the “tensile stress component” predominates in a roll pass with a low degree of work per pass.

In contrast, one of the methods for producing a rolled copper foil according to the present invention has a degree of processing that is 1.1 times greater than the degree of processing of the immediately preceding rolling pass in the second and subsequent passes in the final cold rolling step. A pass schedule is adopted in which one or more rolling passes are included. Specifically, for example, a configuration in which a rolling pass having the largest degree of processing per pass in the second and subsequent passes is executed in the second half of the rolling pass schedule, or the degree of processing per pass is the second pass. The structure which becomes large gradually after that is mentioned. Such a rolling method has a configuration in which the pass schedule is opposite to that of the conventional method. In addition, by executing a rolling pass with a high degree of processing per pass after the second pass of the final cold rolling process (particularly in the second half of the rolling pass schedule), a partial recrystallization phenomenon during the rolling process, etc. It was found that a seed crystal having a cubic structure ({200} _Cu plane oriented crystal grains) was formed in the rolling texture. And it is thought that the seed crystal of this cube structure is contributing to the high orientation growth of the cube texture in recrystallization annealing.

On the other hand, the other manufacturing method of the rolled copper foil which concerns on this invention controls the annealing dough used for a final cold rolling process (process e), and the rolling texture ({220} in a final cold rolling process (process e)) _In the formation process of ( _Cu plane orientation), an appropriate amount (about the degree of relation of “Q ≦ P ≦ R”) of cubic grains ({200} _Cu plane orientation) remains in the rolled texture. There is a point. Then, the crystal grains having a cubic structure dispersed and left in the rolled texture in which the working strain is accumulated function as a seed crystal for forming the cubic texture in the recrystallization annealing, thereby achieving highly oriented growth (especially three-dimensional growth). It is thought that it contributes to (orientation).

  Further, in the manufacturing method of the rolled copper foil, the total degree of work in the final cold rolling process is 80% or more and less than 93%, and the above-mentioned cubic structure crystal grains (crystal grains in which the rotation phenomenon of the crystal plane does not occur) It is considered that the accumulation of processing strain on the copper foil is sufficiently small as compared with the remaining copper foil (for example, the total processing degree of 93% or more). This leads to a small driving force of atomic rearrangement during recrystallization annealing, and can suppress the growth of recrystallized grains (grain coarsening). Suppressing the excessive growth of recrystallized grains leads to the solution of the “Dish Down phenomenon”, which has recently become a problem in the FPC manufacturing process. The “Dish Down Phenomenon” means that when a copper foil is half-etched during the FPC manufacturing process, it tends to be etched in units of crystal grains. A phenomenon in which the surface becomes crater-like.

[Other Embodiments]
In step a, the melting / casting method is not limited, and the material dimensions are not limited. There are no particular restrictions on step b, step c, and step d, and ordinary methods and conditions may be used. Moreover, the thickness of the rolled copper foil used for FPC is generally 50 μm or less, and the thickness of the rolled copper foil of the present invention is not limited as long as it is 50 μm or less, but 20 μm or less is particularly preferable.

[Manufacture of flexible printed wiring boards]
A flexible printed wiring board can be obtained by the manufacturing method currently performed normally using the rolled copper foil of the said embodiment. Moreover, the recrystallization annealing for the rolled copper foil may be a heat treatment performed in a normal CCL process or may be performed in a separate process.

[Effect of the embodiment]
According to the above embodiment of the present invention, the following effects can be obtained.
(1) A rolled copper foil having bending properties superior to those of the conventional art can be obtained.
(2) A rolled copper foil having bending properties superior to those of conventional ones can be produced stably and efficiently (that is, at a low cost).
(3) A flexible wiring such as a flexible printed wiring board (FPC) having bending characteristics superior to those of the conventional one can be obtained.
(4) Not only flexible printed wiring boards (FPC) but also other conductive members that require high bending characteristics (flexion life) (for example, negative electrode materials for automotive lithium-ion batteries that require vibration resistance) Is also applicable.

  EXAMPLES Hereinafter, although this invention is demonstrated in more detail based on an Example, this invention is not limited to these.

[Examples 1-3 and Comparative Examples 1-3]
(Production procedure)
First, tough pitch copper (oxygen content 150 ppm) was produced as a raw material, and an ingot having a thickness of 200 mm and a width of 650 mm was produced. Then, after performing hot rolling to a thickness of 10 mm according to the flow shown in FIG. 5, cold rolling and intermediate annealing (including dough annealing) are repeated as appropriate, and annealing having thicknesses of 0.2 mm and 0.1 mm A dough was produced. As the dough annealing, a heat treatment (Example 1 and Comparative Example 1) held at a temperature of about 700 ° C. for about 1 minute, a heat treatment held at a temperature of about 650 ° C. for about 2 minutes (Example 2), and a temperature of about 690 ° C. Heat treatment (Example 3) held at about 550 ° C., heat treatment held for about 2 minutes at a temperature of about 550 ° C. (Comparative Example 2), and heat treatment held for about 1 minute at a temperature of about 800 ° C. (Comparative Example 3). . The temperature of the fabric annealing is not the set temperature of the annealing furnace but the actual temperature of the copper foil.

  Next, by performing a final cold rolling process on the above-mentioned annealed dough under the conditions shown in Table 1 or Table 2, a rolled copper foil (Examples 1 to 3 and Comparative Examples 1 to 3) having a thickness of 16 μm is obtained. Produced.

(XRD evaluation for rolled copper foil)
XRD evaluation for rolled copper foil (after dough annealing, during the final cold rolling process, after the final cold rolling process, and after recrystallization annealing) was performed as follows. An X-ray diffractometer (manufactured by Rigaku Corporation, model: RAD-B) was used for various XRD measurements (2θ / θ measurement, rocking curve measurement, pole figure measurement, in-plane orientation measurement). The counter cathode (target) was Cu, and the tube voltage and tube current were 40 kV and 30 mA, respectively. The size of the sample used for XRD measurement was about 15 × about 15 mm ² .

The XRD 2θ / θ measurement was performed using a general wide-angle goniometer in the range of 2θ = 40 to 100 °. The slit conditions in the 2θ / θ measurement were 1 ° for the divergent slit, 0.15 mm for the light receiving slit, and 1 ° for the scattering slit. The XRD rocking curve was measured by fixing the detector to the 2θ value of the {200} _Cu plane diffraction peak obtained by 2θ / θ measurement, and scanning the sample to θ = 15 to 35 °. Note that the slit conditions in the rocking curve measurement were the same as in the 2θ / θ measurement.

The conditions for XRD pole figure measurement and in-plane orientation measurement are the general Schulz reflection method, and the β angle is 0 to 360 ° within the range of α = 15 to 90 ° (α = 90 ° perpendicular to the rolling surface). The diffraction intensity of the {220} _Cu surface was measured while scanning (spinning) until 2θ was about 74 ° (2θ value was obtained by using the result of preliminary measurement for each sample). The slit conditions at this time were diverging slit = 1 °, scattering slit = 7 mm, light receiving slit = 7 mm, and Schulz slit (slit height 1 mm). The in-plane orientation measurement was performed with α = 45 ° fixed.

[Example 1 and Comparative Example 1]
(Rolled copper foil after the final cold rolling process)
XRD measurement was performed on each rolled copper foil (thickness: 16 μm) in the state after rolling of Example 1 and Comparative Example 1 manufactured as described above (after the final cold rolling step and before recrystallization annealing). went. FIG. 6 shows an example of the result of in-plane orientation measurement (measurement of {220} _Cu plane at α = 45 °) on the rolled copper foil after the final cold rolling process. 6A shows Example 1, and FIG. 6B shows Comparative Example 1.

As can be seen from FIG. 6, the rolled copper foil of Example 1 has a four-fold symmetry diffraction peak (indicated by a black arrow) present every 90 ± 5 °. The diffraction peak has a diffraction intensity of 1.5 times or more with respect to the minimum intensity of {220} _Cu plane diffraction obtained by β scanning. This means that the {200} _Cu surface has a good in-plane orientation on the rolled surface of the copper foil. In contrast, the rolled copper foil of Comparative Example 1 shows weak diffraction peaks at β≈0 ° (360 °) and 180 °, but hardly shows diffraction peaks at β≈90 ° and 270 °.

FIG. 7 is an example of the result of 2θ / θ measurement performed on the rolled copper foil after the final cold rolling process in Comparative Example 1. FIG. 3 is an example of 2θ / θ measurement results in Example 1. As described above, the rolled copper foil of Example 1 shown in FIG. 3 shows that many {200} _Cu face-oriented crystal grains exist on the rolled face. If the {200} 100 diffraction peak intensity I _{{200} Cu} of _Cu surface in FIG. 3, the diffraction peak intensity I _{{220} Cu} of {220} _Cu plane was 48. In consideration of the X-ray diffraction intensity ratio between the {200} _Cu plane and the {220} _Cu plane in the copper crystal powder being about 2: 1, the rolled copper foil of FIG. } It is considered that the crystal grains of _Cu plane orientation and the grains of {220} _Cu plane orientation exist in substantially the same area ratio.

On the other hand, in the rolled copper foil of Comparative Example 1 shown in FIG. 7, when the diffraction peak intensity I _{{220} Cu} on the {220} _Cu plane is 100, the diffraction peak intensity I _{{200} Cu on the} {200} _Cu plane is 76, and {220} _Cu -oriented crystal grains are overwhelmingly dominant on the rolled surface of the copper foil. In other words, it means that there are very few {200} _Cu plane-oriented crystal grains to be seed crystals.

Considering the results of the in-plane orientation measurement and 2θ / θ measurement described above, the rolled copper foil of Example 1 surely has a three-dimensionally oriented copper crystal serving as a seed crystal for forming a cube texture. I understand that. In contrast, in the rolled copper foil of Comparative Example 1, although {200} _Cu plane-oriented crystal grains exist with respect to the rolled surface, they are poor in in-plane orientation and three-dimensionally oriented seed crystals are formed. It is suggested that there is hardly any.

[Examples 2-3 and Comparative Examples 2-3]
(Annealed fabric)
XRD pole figure measurements were performed on the four types of annealed fabrics prepared as described above (after the fabric annealing and before the final cold rolling step, thicknesses of 0.2 mm and 0.1 mm). FIG. 8 is an example of the result of XRD pole figure measurement of {220} _Cu surface with respect to the rolled surface of the annealed material. 8A shows Example 2, FIG. 8B shows Example 3, FIG. 8C shows Comparative Example 2, and FIG. 8D shows Comparative Example 3. FIG.

  As can be seen from FIG. 8, the standardized strength maximum value Q exists between α = 40 to 50 ° and the standardized strength minimum value S exists between α = 20 to 40 ° in all samples. ing. Here, when the ratio Q / S between the maximum value Q and the minimum value S is taken, Example 2 and Example 3 are 2.2 and 2.6, respectively, whereas in the range of “2 ≦ Q / S ≦ 3”, The values of Comparative Example 2 and Comparative Example 3 are 3.1 and 1.5, respectively.

(Rolled copper foil during final cold rolling process)
The XRD pole figure measurement was performed with respect to the rolled copper foil in the middle of the final cold rolling process using the above four types of dough. FIG. 9 is an example of the result of XRD pole figure measurement of {220} _Cu surface with respect to the rolled surface of the rolled copper foil during the final cold rolling process. 9A shows Example 2, FIG. 9B shows Example 3, FIG. 9C shows Comparative Example 2, and FIG. 9D shows Comparative Example 3. FIG.

  As can be seen from FIG. 9, there is a maximum value P of the normalized strength between α = 25 to 35 ° in each sample (or a sign thereof), and the normalized strength between α = 40 to 50 °. And the normalized strength monotonously increases between α = 85 and 90 °. In addition, it can be seen that the normalized strength of the maximum value Q is reduced as compared with FIGS. 8 (a) to 8 (d). Such a change is considered to be caused by the rotation phenomenon of the copper crystal due to the stress during the rolling process described above.

(Rolled copper foil after the final cold rolling process)
XRD measurement was performed on the rolled copper foil (thickness 16 μm) in the state after rolling (prepared after the final cold rolling step and before recrystallization annealing) produced as described above. FIG. 10 is an example of the result of XRD pole figure measurement of {220} _Cu surface on the rolled copper foil after the final cold rolling process. 10 (a) is Example 2, FIG. 10 (b) is Example 3, FIG. 10 (c) is Comparative Example 2, and FIG. 10 (d) is Comparative Example 3.

  As can be seen from FIG. 10, the rolled copper foils of Example 2 and Example 3 have a relationship of “Q ≦ P ≦ R”, while the rolled copper foil of Comparative Example 2 has “Q> P, Q> R”. In the rolled copper foil of Comparative Example 3, the maximum value Q is hardly detected. The relationship of “Q ≦ P ≦ R” means that an in-plane oriented cubic structure seed crystal is present in an appropriate amount, and a rolling texture in which processing strain is accumulated is present in a necessary and sufficient amount. it seems to do. On the other hand, Comparative Example 3 in which almost no maximum value Q was detected suggests that there are almost no in-plane oriented seed crystals of the cubic structure. Further, in Comparative Example 2 where “Q> P, Q> R”, it is considered that in-plane oriented copper crystals of a cubic structure exist, but the formation of a rolling texture with accumulated work strain is insufficient. It suggests.

FIG. 11 shows an example of the result of 2θ / θ measurement performed on the rolled copper foil after the final cold rolling process. 11A shows the second embodiment, FIG. 11B shows the third embodiment, and FIG. 11C shows the second comparative example. As can be seen from FIG. 11, the rolled copper foils of Example 2 and Example 3 show that there are many {200} _Cu face-oriented crystal grains on the rolled surface. In contrast, the rolled copper foil of Comparative Example 2 has many {200} _Cu face-oriented crystal grains on the rolled face, while many {111} _Cu face-oriented crystal grains exist, and {220} _Cu The number of plane-oriented crystal grains is reduced. In Comparative Example 3, substantially the same results as in FIG. 7 were obtained, and there were very few {200} _Cu plane-oriented crystal grains serving as seed crystals, and {220} _Cu plane-oriented crystal grains were dominant. .

Considering the results of the above pole figure measurement and 2θ / θ measurement in combination, the rolled copper foils of Examples 2 to 3 have an appropriate amount of three-dimensionally oriented copper crystals that become seed crystals for forming the cube texture. You can see that On the other hand, in the rolled copper foil of Comparative Example 3, although there are crystal grains with {200} _Cu plane orientation with respect to the rolling surface, they are poor in in-plane orientation and three-dimensionally oriented seed crystals are formed. It is suggested that there is hardly any. Further, in Comparative Example 2, although {200} _Cu plane oriented crystal grains in the cubic structure remain, the formation of the “rolling texture with accumulated work strain” that serves as the driving force for the formation of the cubic texture is not possible. It is considered sufficient.

[Examples 1-3 and Comparative Examples 1-3]
(Rolled copper foil after recrystallization annealing)
Each rolled copper foil (thickness 16μm, final cold rolling process completed) produced as described above is subjected to recrystallization annealing that is held at a temperature of 180 ° C. for 60 minutes, and then XRD measurement is performed. A] × [B] × [C] was evaluated. The results of the cubic texture ratio [A] are shown in Table 3, the results of out-of-plane orientation ratio [B] and in-plane orientation ratio [C] are shown in Table 4, and the total orientation ratio [A] × [B] × The results of [C] are shown in Table 5.

As described above, [A], [B], and [C] were calculated by the following equations, respectively.
Cubic texture ratio [A] = I _{{200} Cu} / (I _{{111} Cu} + I _{{200} Cu} + I _{{220} Cu} + I _{{311} Cu} )
Out-of-plane orientation ratio of cubic texture [B] = Δθ _FWHM / Δθ _IW
Out-of-plane orientation ratio of cubic texture [C] = Δβ _FWHM / Δβ _IW

  As is clear from the results in Table 5, the rolled copper foils of Examples 1 to 3 have a total orientation ratio [A] × [B] × [C] sufficiently higher than 0.5. The rolled copper foil had an overall orientation ratio of less than 0.5. This is because, in the rolled copper foil after the final cold rolling process, whether or not there is a three-dimensionally oriented copper crystal serving as a seed crystal for the formation of a cubic texture and / or formation of a rolled texture that accumulates processing strain. This is thought to be due to the degree of the above.

(Bending characteristics of rolled copper foil after recrystallization annealing)
Evaluation of the bending characteristic with respect to each rolled copper foil (Examples 1-3 and Comparative Examples 1-3, thickness 16 micrometers, after recrystallization annealing) produced as mentioned above was performed as follows. FIG. 12 is a schematic diagram showing an outline of bending characteristic evaluation (sliding bending test). Sliding and bending test equipment manufactured by Shin-Etsu Engineering Co., Ltd., model: SEK-31B2S, R = 2.5 mm, amplitude stroke = 10 mm, frequency = 25 Hz (amplitude velocity = 1500 times / min), sample width = 12.5 mm The sample length was 220 mm, and the measurement was performed under the condition that the longitudinal direction of the sample piece was the rolling direction. Measurement was performed for 10 samples. The results are shown in Table 6.

  As is apparent from the results in Table 6, it can be seen that the rolled copper foils of Examples 1 to 3 have a bending life frequency (high bending characteristics) that is twice or more that of Comparative Examples 1 to 3. . This result is considered to be due to the high overall orientation ratio (see Table 5) of the cube texture in Examples 1 to 3.

It is a schematic diagram which shows the main crystal planes of the copper crystal relevant to this invention. It is the schematic which shows the relationship of the incident X-ray in X-ray diffraction, a detector, a sample, and a scanning axis. In the rolled copper foil which concerns on this invention, it is an example of the result of having performed X-ray diffraction 2 (theta) / (theta) measurement with respect to the rolling surface in the state after a final cold rolling process and before recrystallization annealing. It is a schematic diagram which shows the relationship between the quality of crystal orientation, and the half-value width and integral width of a diffraction peak. It is a flowchart which shows one example of the manufacturing process of the rolled copper foil which concerns on this invention. FIG. 6A is an example of the result of in-plane orientation measurement (measurement of {220} _Cu surface at α = 45 °) on the rolled copper foil after the final cold rolling process. FIG. 6B is Comparative Example 1. It is an example of the result of having performed 2 (theta) / (theta) measurement with respect to the rolled copper foil after the last cold rolling process in the comparative example 1. FIG. FIG. 8A is an example of the result of XRD pole figure measurement of {220} _Cu surface on the rolled surface of the annealed material, FIG. 8A is Example 2, FIG. 8B is Example 3, and FIG. (c) is Comparative Example 2, and FIG. 8 (d) is Comparative Example 3. FIG. 9 (a) shows an example of the result of XRD pole figure measurement of {220} _Cu plane on the rolled surface of the rolled copper foil in the middle of the final cold rolling process. ) Is Example 3, FIG. 9C is Comparative Example 2, and FIG. 9D is Comparative Example 3. Fig. 10 (a) shows Example 2 and Fig. 10 (b) shows the result of XRD pole figure measurement of {220} _Cu surface on the rolled copper foil after the final cold rolling process. Example 3 and FIG. 10C are Comparative Example 2, and FIG. FIG. 11 (a) shows an example of the result of 2θ / θ measurement performed on the rolled copper foil after the final cold rolling process, FIG. 11 (a) shows Example 2, FIG. 11 (b) shows Example 3, and FIG. c) is Comparative Example 2. It is a schematic diagram showing the outline of bending characteristic evaluation (sliding bending test).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Copper foil, 2 ... Sample fixing plate, 2a ... Screw, 3 ... Vibration transmission part, 4 ... Oscillation drive body,
R: Curvature.

Claims (8)

A rolled copper foil after the final cold rolling process and before recrystallization annealing,
It consists of a copper foil that develops a cubic texture by recrystallization annealing,
The result obtained by X-ray diffraction pole figure measurement based on the rolling surface, and the { 220 } _Cu plane diffraction peak of the copper crystal obtained by β scanning at the α angle = 45 ° of the pole figure measurement is 90 ± 5 with a β angle of 90 ± 5. A rolled copper foil characterized by the presence of crystal grains which are present every 4 ° and show fourfold symmetry. In the rolled copper foil according to claim 1,
The rolled copper foil, wherein the diffraction peak showing the 4-fold symmetry has a diffraction intensity of 1.5 times or more with respect to a minimum intensity of { 220 } _Cu plane diffraction of the copper crystal obtained by the β scan. In the rolled copper foil of Claim 1 or Claim 2,
Results obtained by X-ray diffraction pole figure measurement based on the rolled surface, and the standard of { 220 } _Cu plane diffraction peak of copper crystal obtained by β scan at each α angle with the α angle of the pole figure measurement as the horizontal axis When the graphed strength is plotted on the vertical axis,
The maximum value P of the normalized strength exists between α = 25 to 35 °, the maximum value Q of the normalized strength exists between α = 40 to 50 °, and between α = 85 to 90 ° The normalized strength is monotonically increasing,
The rolled copper foil, wherein the maximum value P, the maximum value Q, and the normalized strength value R at α = 90 ° are “Q ≦ P ≦ R”. In the rolled copper foil according to any one of claims 1 to 3,
A rolled copper foil characterized in that the intensity of a diffraction peak of a copper crystal is “I _{{200} Cu} ≧ I _{{ 220 } Cu} ” as a result obtained by X-ray diffraction 2θ / θ measurement on the rolled surface.
It is the rolled copper foil after giving recrystallization annealing with respect to the rolled copper foil of any one of Claims 1 thru | or 4,
The ratio [A] of the cube texture calculated from the X-ray diffraction 2θ / θ measurement with respect to the rolled surface, and the out-of-plane orientation ratio [B] calculated from the X-ray diffraction rocking curve measurement for the crystal grains of the cube texture And the in-plane orientation ratio [C] calculated from the X-ray diffraction pole figure measurement based on the rolling surface for the crystal grains of the cubic texture is “[A] × [B] × [C ] A rolled copper foil characterized by satisfying ≧ 0.5 ”. It is a rolled copper foil after recrystallization annealing after the final cold rolling process,
It consists of a copper foil that develops a cubic texture by recrystallization annealing,
The ratio [A] of the cube texture calculated from the X-ray diffraction 2θ / θ measurement with respect to the rolled surface, and the out-of-plane orientation ratio [B] calculated from the X-ray diffraction rocking curve measurement for the crystal grains of the cube texture The product of the crystal texture of the cubic texture and the in-plane orientation ratio [C] calculated from the X-ray diffraction pole figure measurement based on the rolling surface is “[A] × [B] × [C]”. A rolled copper foil characterized by ≧ 0.5 ”. X-ray diffraction pole figure measurement based on the rolled surface of a rolled copper foil made of a copper foil whose cubic texture is developed by recrystallization annealing and before the recrystallization annealing after the final cold rolling step From the results obtained by the above, the { 220 } _Cu plane diffraction peak of the copper crystal obtained by the β scan at the α angle = 45 ° of the pole figure measurement is present every 90 ± 5 ° of the β angle and exhibits 4-fold symmetry. A method for producing a rolled copper foil in which crystal grains exist,
In the rolling pass after the second pass in the final cold rolling step, one or more rolling passes having a working degree 1.1 times or more larger than the working degree of the immediately preceding rolling pass are included,
The final pass of the final cold rolling step or the pass immediately before the final has the greatest degree of processing per pass in the second and subsequent passes,
The method for producing a rolled copper foil, wherein the total degree of work in the final cold rolling step is 80% or more and less than 90%. A rolled copper foil composed of a copper foil in which a cubic texture is developed by recrystallization annealing,
Result obtained by X-ray diffraction pole figure measurement based on the rolling surface of the rolled copper foil after the final cold rolling process and before recrystallization annealing, and obtained by β scanning at α angle = 45 ° of pole figure measurement The { 220 } _Cu surface diffraction peak of the copper crystal is present every 90 ± 5 ° of the β angle, and there are crystal grains exhibiting 4-fold symmetry,
When the graph shows the normalized intensity of the { 220 } _Cu plane diffraction peak of the copper crystal obtained by β scanning at each α angle as the abscissa and the α axis of the pole figure measurement as the ordinate, α = 25 to 35 ° There is a maximum value P of the normalized strength in between, there is a maximum value Q of the normalized strength in the range of α = 40 to 50 °, and the normalized strength is monotonous in the range of α = 85 to 90 °. A method for producing a rolled copper foil in which the maximum value P, the maximum value Q, and the normalized strength value R at α = 90 ° are “Q ≦ P ≦ R”,
The result obtained by X-ray diffraction pole figure measurement based on the rolling surface in the rolled copper foil after the dough annealing and before the final cold rolling step, with the α angle of the pole figure measurement as the horizontal axis at each α angle When the normalized intensity of the { 220 } _Cu plane diffraction peak of the copper crystal obtained by β-scanning is expressed as a graph, the maximum value Q of the normalized intensity exists between α = 40 to 50 °, Annealing a rolled copper foil in which the minimum value S of the normalized strength exists between α = 20 to 40 ° and the ratio of the maximum value Q to the minimum value S is “2 ≦ Q / S ≦ 3” Used as dough,
The method for producing a rolled copper foil, wherein a total degree of processing in the final cold rolling step is 80% or more and less than 93%.

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