JP2013119631A - Rolled copper foil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolled copper foil having low stiffness and also, excellent bending property after recrystallization annealing process.SOLUTION: Diffraction peak strengths of a plurality of crystal faces in parallel with a main surface, satisfy following expressions: I/(I+I+I+I+I)≥0.50; (I+I)/(I+I)≥1.0; I/I≤8.0; I/I≤30; I/I≥7.0; I/I≥10; 1.0≤I/I≤15; I/I≤10; I/I≥0.30; 1.0≤I/I≤20; 1.0≤I/I≤75; and 0.50≤I/I≤20.

Description

  The present invention relates to a rolled copper foil, and more particularly to a rolled copper foil used for a flexible printed wiring board.

Since a flexible printed circuit (FPC) is thin and excellent in flexibility, it has a high degree of freedom in mounting on an electronic device or the like. Therefore, folding parts of folding cellular phones, movable parts such as digital cameras and printer heads, hard disk drives (HDD: Hard Disk Drive), digital versatile disks (DVDs), compact disks (CDs: Compact Disks), etc. FPC is used for wiring of movable parts of the disk-related equipment. Therefore, excellent bending characteristics have been required for rolled copper foil used as FPC and its wiring material.

  Rolled copper foil for FPC is manufactured through processes such as hot rolling, cold rolling, etc., and through an adhesive or directly by FPC base film (base material) made of resin such as polyimide and heating. They are bonded together and subjected to surface processing such as etching to form wiring. The bending property of the rolled copper foil is significantly improved in the softened state by recrystallization after annealing than in the work-hardened hard state after cold rolling. Therefore, for example, in the above manufacturing process, the rolled copper foil is cut using the rolled copper foil after cold rolling while avoiding deformation such as elongation and wrinkle, and after being stacked on the base material, A manufacturing method is adopted in which the rolled copper foil and the base material are brought into close contact with each other by heating also for crystal annealing.

On the premise of the manufacturing process of the FPC, various studies have been made so far on a rolled copper foil having excellent bending characteristics and a method for manufacturing the rolled copper foil, and the {002} plane ({{
It has been reported many that the flexural properties improve as the (200} plane) develops.

Therefore, for example, in Patent Document 1, annealing immediately before the final cold rolling is performed under the condition that the average grain size of the recrystallized grains is 5 μm to 20 μm, and the degree of rolling in the final cold rolling is 90% or more. It is said. Thereby, in the state conditioned to the recrystallized structure, the strength (I) of the (200) plane determined by X-ray diffraction of the rolled surface is the strength of the (200) plane determined by X-ray diffraction of fine powder copper ( For I ₀ ), a cubic texture with I / I ₀ > 20 is obtained.

Further, for example, in Patent Document 2, the degree of development of the cube texture before the final cold rolling is increased, the degree of processing in the final cold rolling is set to 93% or more, and further, recrystallization annealing is performed (200) A rolled copper foil whose surface has an integrated strength of I / I ₀ ≧ 40 and whose cubic texture is remarkably developed is obtained.

  Further, for example, in Patent Document 3, the total work degree in the final cold rolling process is set to 94% or more, and the work degree per pass is controlled to 15 to 50%. Further, by recrystallization annealing, the in-plane orientation degree Δβ of the {111} plane with respect to the {200} plane of the rolled plane obtained by X-ray diffraction pole figure measurement is 10 ° or less, and is a cubic texture on the rolled plane. The ratio of the normalized diffraction peak intensity [a] of the {200} plane and the normalized diffraction peak intensity [b] between the {200} plane twin crystal region is [a] / [b] ≧ A crystal grain orientation state of 3 is obtained.

  Thus, in the prior art, by increasing the total degree of work in the final cold rolling process, the cubic texture of the rolled copper foil is developed after the recrystallization annealing process to improve the bending characteristics.

Japanese Patent No. 3009383 Japanese Patent No. 3856616 Japanese Patent No. 4285526

  However, as described in Patent Documents 1 to 3, even if a large amount of cube texture is expressed, the {002} plane that is the cube texture does not occupy 100% in the rolled copper foil having a polycrystalline structure. . That is, in the rolled copper foil, a plurality of crystal planes other than the {002} plane are mixed without being controlled, and the crystal grains having the plurality of crystal faces have various effects on various properties of the rolled copper foil. It is thought that.

  In recent years, with the downsizing and thinning of electronic equipment, not only high bending properties but also low stiffness (low repulsion) are achieved for rolled copper foil for FPC from the viewpoint of ease of wiring incorporation during assembly. The demand for sex is also increasing.

  An object of the present invention is to provide a rolled copper foil that can have excellent bending characteristics as well as low stiffness after the recrystallization annealing step.

According to a first aspect of the present invention, there is provided a rolled copper foil having a main surface and having a plurality of crystal planes parallel to the main surface after the final cold rolling step and before the recrystallization annealing step, Crystal planes include {022} plane, {002} plane, {113} plane, {111} plane, and {133} plane, and can be obtained by X-ray diffraction measurement by the 2θ / θ method with respect to the main surface. When the diffraction peak intensities of the crystal planes are I _{022} , I _{002} , I _{113} , I _{111} , and I _{133} , respectively, I _{022} / (I _{022} + I _{002} + I _{113} + I _{111} + I _{133} ) ≧ 0.50 and (I _{002} + I _{113} ) / (I _{111} + I _{133} ) ≧ 1.0 a _{I {022} / I {002} } ≦ 8.0, I { _{22} / I {113}} is ≦ _30, an _{I {022} / I {111} } ≧ 7.0, I {022} / I {133} is _{≧ 10, 1.0 ≦ I {002} } / I _{113} ≦ 15, I _{111} / I _{133} ≦ 10, I _{113} / I _{111} ≧ 0.30, and 1.0 ≦ I _{002} / I Provided is a rolled copper foil in which _{111} ≦ 20, 1.0 ≦ I _{002} / I _{133} ≦ 75, and 0.50 ≦ I _{113} / I _{133} ≦ 20 Is done.

  According to the 2nd aspect of this invention, the rolled copper foil as described in a 1st aspect which is 20 micrometers or less in thickness by the said last cold rolling process with a total workability of 90% or more is provided.

  According to the third aspect of the present invention, the rolled copper foil according to the first or second aspect mainly comprising oxygen-free copper having a purity of 99.96% or more or tough pitch copper having a purity of 99.9% or more. Is provided.

  According to the 4th aspect of this invention, the rolled copper foil in any one of the 1st-3rd aspect to which at least any one of silver, boron, titanium, and tin is added is provided.

  According to the 5th aspect of this invention, the rolled copper foil in any one of the 1st-4th aspect which is an object for flexible printed wiring boards is provided.

According to the present invention, after the recrystallization annealing step, excellent bending characteristics can be provided along with low stiffness.

It is a flowchart which shows the manufacturing process of the rolled copper foil which concerns on one Embodiment of this invention. It is a schematic diagram of the sliding bending test apparatus which measures the bending characteristic of the rolled copper foil which concerns on the Example of this invention. It is a figure which shows the outline | summary of the test method of the stiffness property of the rolled copper foil which concerns on the Example of this invention. It is a reverse pole figure of a pure copper type metal, and (a) is a reverse pole figure showing a crystal rotation direction by tensile deformation, and (b) is a reverse pole figure showing a crystal rotation direction by compression deformation. It is a reverse pole figure which shows the crystal orientation of the rolled copper foil after a final cold rolling process and before a recrystallization annealing process.

<Knowledge obtained by the present inventors>
As described above, in order to obtain a rolled copper foil having high bending characteristics required for FPC applications, it is better to develop the cube orientation of the rolled surface. The present inventors have also conducted various experiments in order to increase the occupation ratio of the cube orientation. And from the experimental results so far, when the {022} plane existing after the final cold rolling step is tempered to recrystallization by subsequent recrystallization annealing, it becomes the {002} plane, that is, the cubic orientation. It was confirmed.

  On the other hand, since the rolled copper foil is polycrystalline, the entire rolled surface is not 100% occupied by one crystal surface. For example, in the state after the final cold rolling step, other than the {022} surface which is the main orientation A plurality of sub-orientation crystal planes coexist. Accordingly, the present inventors have focused on the sub-orientation crystal planes that have been made unnecessary so far, and have examined whether new performance can be added by these sub-orientation crystal planes while maintaining high bending characteristics. .

  As a result of such diligent research, the present inventors have reduced the stiffness as a new added value to the rolled copper foil by controlling the ratio of the crystal plane of the sub-orientation without reducing the occupation ratio of the main orientation. It was found that (low resilience) can be imparted.

  The present invention is based on the above findings found by the inventors.

<One Embodiment of the Present Invention>
(1) Configuration of Rolled Copper Foil First, the configuration of the rolled copper foil according to an embodiment of the present invention, such as the crystal structure, will be described.

  The rolled copper foil which concerns on this embodiment is comprised by the plate shape provided with the rolling surface as a main surface, for example. This rolled copper foil is subjected to, for example, an ingot made of oxygen-free copper (OFC: Oxygen-Free Copper) or tough pitch copper by performing a hot rolling process or a cold rolling process, which will be described later, to a predetermined thickness. It is a rolled copper foil after a hot rolling process and before a recrystallization annealing process. That is, in the present embodiment, the rolled copper foil is thickened by a final cold rolling process in which the total degree of processing is 90% or more, more preferably 94% or more so that it can be used for flexible wiring materials such as FPC. After that, as described above, for example, a recrystallization annealing process is performed to serve as a bonding process with an FPC substrate, and the recrystallization provides excellent bending characteristics. It is intended.

The oxygen-free copper used as a raw material is a copper material having a purity specified in JIS C1020, H3100, etc. of 99.96% or more. The oxygen content may not be completely zero, and for example, oxygen of about several ppm may be included. Also, tough pitch copper is, for example, JIS C1100,
It is a copper material having a purity specified by H3100 or the like of 99.9% or more. In the case of tough pitch copper, the oxygen content is, for example, about 100 ppm to 600 ppm. A predetermined additive such as silver (Ag) may be added to these copper materials to form a copper alloy, which may be a rolled copper foil in which various properties such as heat resistance are adjusted. The rolled copper foil according to the present embodiment can include both pure copper and a copper alloy, and the influence of the present embodiment on the effects of the present embodiment due to the raw copper material and additives hardly occurs.

The total degree of work in the final cold rolling process is defined as T _B is the thickness of the workpiece (copper plate material) before the final cold rolling process, and T _A is the thickness of the workpiece after the final cold rolling process. Then, the total degree of processing (%) = [(T _B −T _A ) / T _B ] × 100. By setting the total workability to 90% or more, more preferably 94% or more, a rolled copper foil having high bending properties can be obtained.

The rolled copper foil has a plurality of crystal planes parallel to the rolled surface. Specifically, after the final cold rolling step and before the recrystallization annealing step, the plurality of crystal planes include {022} plane, {002} plane, {113} plane, {111} plane, and { 133} plane is included. Further, the diffraction peak intensities of the crystal planes obtained by performing X-ray diffraction measurement on the main surface of the rolled copper foil by 2θ / θ method are I _{022} , I _{002} , I _{113} , I _{When {111}} and I _{133} are set, the diffraction peak intensities of the crystal planes are in a relationship in which all of the following formulas (1) to (12) hold.

I _{022} / (I _{022} + I _{002} + I _{113} + I _{111} + I _{133} ) ≧ 0.50 (1)
(I _{002} + I _{113} ) / (I _{111} + I _{133} ) ≧ 1.0 (2)
I _{022} / I _{002} ≦ 8.0 (3)
I _{022} / I _{113} ≦ 30 (4)
I _{022} / I _{111} ≧ 7.0 (5)
I _{022} / I _{133} ≧ 10 (6)
1.0 ≦ I _{002} / I _{113} ≦ 15 (7)
I _{111} / I _{133} ≦ 10 (8)
I _{113} / I _{111} ≧ 0.30 (9)
1.0 ≦ I _{002} / I _{111} ≦ 20 (10)
1.0 ≦ I _{002} / I _{133} ≦ 75 (11)
0.50 ≦ I _{113} / I _{133} ≦ 20 (12)

As described above, the {022} plane changes to the {002} plane after the recrystallization annealing process, and improves the bending characteristics of the rolled copper foil. The above formula (1) indicates that the diffraction peak intensity I _{022} of the _{022} plane is sufficiently high, 50% or more, compared with the diffraction peak intensity of the crystal plane of other orientations. Yes.

  In addition, during the rolling process such as the final cold rolling process, the rolled copper material is subjected to compressive stress and tensile stress weaker than the compressive stress. The copper crystal in the copper material undergoes a rotation phenomenon due to the stress during the rolling process, and changes to the {022} plane through several paths. The larger the compressive stress, the easier it is to go through the {002} plane and the {113} plane, and the higher the tensile stress, the easier it is to go through the {111} plane and the {133} plane, respectively changing to the {022} plane.

Therefore, the above formula (2) indicates that the ratio of (I _{002} + I _{113} ) is higher than (I _{111} + I _{133} ), and the compressive stress is dominant.

In addition, the above formulas (3) to (6) are obtained by rotating to the {022} plane, and the {002} plane, {113} plane, {111} plane, and {133} plane that were insufficiently rotated. And the ratio of diffraction peak intensities.

  In addition, the above equations (7) and (8) are obtained from the {002} plane and the {113} plane, and the {111} plane and the {133} plane, which are seen in the respective paths changing to the {022} plane. The ratio of the diffraction peak intensity is shown.

  Moreover, said Formula (9)-(12) has shown the ratio of the diffraction peak intensity of the crystal planes seen in a different path | route, respectively. That is, by considering the expressions (9) to (12) together with the above expressions (7) and (8), all ratios of diffraction peak intensities between crystal planes that did not rotate to the {022} plane are shown. Will be.

  As described above, based on the experimental experience of the present inventors, a close relationship is recognized between the stiffness and the ratio of crystal planes in each sub-orientation. That is, it is considered that the balance of the diffraction peak intensity of each crystal plane affects the stiffness. Specifically, before the recrystallization annealing step according to the present embodiment, when the ratio of the diffraction peak intensity of the crystal planes of each sub-orientation of the rolled copper foil satisfies the above proportional relationship, the crystal orientation after the recrystallization annealing step In particular, an effect of low stiffness can be obtained. In addition, before recrystallization annealing, it is necessary to consider the influence on the stiffness by work hardening.

  That is, in this embodiment, in the recrystallization annealing process, the {022} plane that is the main orientation changes to the {002} plane, but the {002} plane, the {113} plane, and the {111} plane that are the sub-directions. The {133} plane hardly changes before and after the recrystallization annealing process, and the ratio of the diffraction peak intensities of the sub-oriented crystal faces is substantially the same after the recrystallization annealing process. By relieving work hardening by the recrystallization annealing process (that is, by eliminating strain), the effect of the sub-azimuth is exhibited without changing the sub-azimuth itself.

  Thus, in the rolled copper foil according to the present embodiment before the recrystallization annealing step, it is only necessary that the ratio of the diffraction peak intensities of the crystal planes in each sub-orientation satisfies the above proportional relational expression. That is, the sub-direction of the rolled copper foil in a state before recrystallization annealing, that is, the rolled copper foil after the final cold rolling process may be controlled.

In addition, the proportional relationship between the diffraction peak intensities of the crystal planes shown in the above formulas (1) to (12) is such that if the range of one or a plurality of formulas is changed, the ranges of other formulas are also changed in conjunction with each other. It is necessary to pay attention to. That is, for example, in order to reduce the upper limit range of Expression (3), for example, the value of I _{022} may be reduced. However, in this case, the numerator of the formula (5) also becomes small, and the value of the formula (5) may fall below the lower limit of 7.0. Such a relationship applies to all of the above formulas (1) to (12).

  Accordingly, the optimum condition is that which satisfies all the predetermined ranges defined in the above (1) to (12). By making the rolled copper foil which concerns on this embodiment into the said structure, it can be set as the rolled copper foil which can be equipped with the outstanding bending characteristic with low stiffness after a recrystallization annealing process.

(2) Manufacturing method of rolled copper foil Next, the manufacturing method of the rolled copper foil which concerns on one Embodiment of this invention is demonstrated using FIG. FIG. 1 is a flow chart showing the manufacturing process of the rolled copper foil according to this embodiment.

(Ingot preparation step S10)
As shown in FIG. 1, first, an ingot is prepared by casting using oxygen-free copper (OFC) or tough pitch copper as a raw material. The ingot is formed in a plate shape having a predetermined thickness and a predetermined width, for example. In order to adjust various characteristics of the rolled copper foil, a predetermined additive may be added to the oxygen-free copper or tough pitch copper as the raw material.

  The above-mentioned various characteristics that can be adjusted with the additive include, for example, heat resistance. As described above, with respect to the rolled copper foil for FPC, the recrystallization annealing process for obtaining a high bending property is performed, for example, also as a bonding process with an FPC base material. The heating temperature at the time of bonding is set in accordance with, for example, the curing temperature of a base material made of an FPC resin or the like, the curing temperature of an adhesive to be used, and the range of temperature conditions is wide and diverse. In order to adjust the softening temperature of the rolled copper foil to the heating temperature set in this way, an additive capable of adjusting the heat resistance of the rolled copper foil may be added. Typical examples of additives that increase or decrease heat resistance are described in, for example, the following technical documents (a) to (c). In addition, as ingots used in the present embodiment, ingots with no additive added and ingots added with several kinds of additives are exemplified in Table 1 below.

(A) Japanese Patent Laid-Open No. 04-056754
(B) JP2011-001622A
(C) Hori Shigenori, 2 others, “Effect of additive elements on copper recrystallization temperature”, Journal of Copper Technology Research, 1981, Vol. 20, p205-218

  In addition, the temperature conditions in the below-mentioned intermediate annealing process S32 and dough annealing process S40 are suitably changed according to the heat resistance of a copper material and an additive. However, the copper material, the additive, the temperature conditions of the annealing steps S32 and S40, etc. have little influence on the effect of the present embodiment.

(Hot rolling process S20)
Next, the prepared ingot is hot-rolled to obtain a plate material having a thickness smaller than a predetermined thickness after casting.

(Repetition step S30)
Subsequently, a repeating step S30 is performed in which the cold rolling step S31 and the intermediate annealing step S32 are repeatedly performed a predetermined number of times. That is, work hardening is relieved by subjecting the plate material that has been cold-rolled and work hardened to an annealing treatment to anneal the plate material. By repeating this a predetermined number of times, a copper strip called “dough” is obtained. When an additive for adjusting heat resistance is added to the copper material, the temperature condition of the annealing treatment is appropriately changed according to the heat resistance of the copper material.

(Dough annealing step S40)
Subsequently, the above-mentioned copper strip (fabric) is subjected to a fabric annealing treatment to obtain an annealed fabric. Also in the fabric annealing treatment, the temperature condition is appropriately changed according to the heat resistance of the copper material. At this time, it is preferable that the material annealing step S40 is performed under a temperature condition that can sufficiently relieve the processing distortion caused by each of the above steps, for example, a temperature condition substantially equivalent to a complete annealing treatment.

(Final cold rolling process S50)
Next, the final cold rolling step S50 is performed. The final cold rolling is also referred to as finish cold rolling, and cold rolling to be finished is applied to the annealed fabric a plurality of times. At this time, the total workability is set to 90% or more, more preferably 94% so that a rolled copper foil having high bending characteristics can be obtained. Moreover, it is preferable to gradually reduce the degree of processing per one (one pass) as the annealed dough becomes thinner each time cold rolling is repeated a plurality of times. Here, the degree of processing per pass follows the example of the total degree of processing, and the thickness of the workpiece before rolling of the n-th pass is T _Bn, and the thickness of the workpiece after rolling is T _An. Then, the degree of processing per pass (%) = [(T _Bn −T _An ) / T _Bn ] × 100.

  At the time of rolling, an object to be processed such as annealed dough is reduced in thickness by, for example, being drawn into a gap between a pair of rolls facing each other and drawn to the opposite side. The speed of the workpiece is slower than the rotation speed of the roll on the entrance side before being drawn into the roll, and faster than the rotation speed of the roll on the exit side after being drawn out of the roll. Accordingly, the workpiece is subjected to compressive stress on the entrance side and tensile stress on the exit side. In order to thinly process a workpiece, compressive stress> tensile stress must be satisfied. By adjusting the degree of processing per pass, it is possible to adjust the strength of each stress and the ratio of stress components (compression component and tensile component) on the premise that compressive stress> tensile stress. Thereby, as described above, the path of change to the {022} plane is changed, and the ratio of the crystal planes in the sub-orientation can be adjusted.

  In the final cold rolling step S50, it is preferable to control the position of the neutral point described below to move toward the outlet side of the roll every time cold rolling is repeated a plurality of times. That is, as described above, the speed of the workpiece whose magnitude relationship is reversed between the inlet side and the outlet side with respect to the rotational speed of the roll is the rotational speed of the roll at some position between the inlet side and the outlet side. Is equal to A position where both speeds are equal is called a neutral point, and the pressure applied to the workpiece is maximized at the neutral point.

  The position of the neutral point can be controlled by adjusting a combination of forward tension, backward tension, rolling speed (roll rotational speed), roll diameter, degree of processing, rolling load, and the like. That is, by controlling the position of the neutral point, the strength of compressive stress and tensile stress and the ratio of stress components can be adjusted, and the ratio of crystal planes in the sub-orientation can be adjusted.

(Surface treatment step S60)
A predetermined surface treatment is performed on the copper strip that has undergone the above steps. The rolled copper foil which concerns on this embodiment is manufactured by the above.

  In the present embodiment, the cold rolling is performed in the final cold rolling step S50 so that the total workability is 90% or more, more preferably 94% or more. Further, the degree of processing per pass and the position of the neutral point in each pass are controlled. Thereby, the ratio of the crystal planes of the main orientation and the sub-orientation can be adjusted, and the diffraction peak intensity of each crystal plane can be adjusted so as to satisfy the above-mentioned formulas (1) to (12). Therefore, after the recrystallization annealing process described later, it is possible to produce a rolled copper foil that can have excellent bending characteristics as well as low stiffness.

(3) Manufacturing method of flexible printed wiring board Next, the manufacturing method of the flexible printed wiring board (FPC) using the rolled copper foil which concerns on one Embodiment of this invention is demonstrated.

(Recrystallization annealing process (CCL process))
First, the rolled copper foil according to the present embodiment is cut into a predetermined size, and bonded to an FPC base material made of a resin such as polyimide to form a CCL (Copper Clad Laminate). At this time, either a method of forming a three-layer material CCL that is bonded using an adhesive or a method of forming a two-layer material CCL that is directly bonded without using an adhesive may be used. When an adhesive is used, the adhesive is cured by heat treatment, and the rolled copper foil and the base material are brought into close contact with each other to be integrated. When no adhesive is used, it is brought into close contact by heating and pressing. The heating temperature and time can be appropriately selected according to the curing temperature of the adhesive or the base material, and can be set to 1 to 120 minutes at a temperature of 150 to 300 ° C., for example.

  As described above, the heat resistance of the rolled copper foil is adjusted according to the heating temperature at this time. Therefore, the rolled copper foil is softened and recrystallized by the heating, and the bending characteristics of the rolled copper foil can be remarkably improved. That is, the CCL process of bonding the rolled copper foil to the base material also serves as a recrystallization annealing process for the rolled copper foil. Thus, in the process until the rolled copper foil is bonded to the base material, the rolled copper foil can be handled in the work-hardened state after the cold rolling process, and the elongation when the rolled copper foil is bonded to the base material is increased. It is possible to prevent deformation such as wrinkles and creases.

(Surface machining process)
Next, a surface processing step is performed on the rolled copper foil bonded to the base material. In the surface processing step, for example, a wiring forming step for forming copper wiring or the like on the rolled copper foil by using a technique such as etching, and surface treatment such as plating for improving the connection reliability between the copper wiring and other electronic members. And a protective film forming step of forming a protective film such as a solder resist so as to cover a part of the copper wiring in order to protect the copper wiring and the like.

  As described above, the FPC using the rolled copper foil according to this embodiment is manufactured.

  As described above, in the present embodiment, the recrystallization annealing process is performed on the rolled copper foil also serving as the CCL process. Thereby, the rolled copper foil which has a recrystallized structure is obtained. At this time, the {022} plane which is the main orientation changes to a {002} plane. Therefore, the rolled copper foil excellent in the bending characteristic can be obtained. On the other hand, the {002} plane, {113} plane, {111} plane, and {133} plane, which are sub-azimuths, are ratios while maintaining the state after the final cold rolling process in the rolled copper foil manufacturing process. Is hardly changed, and by removing the influence of work hardening by the recrystallization annealing step, the effect of the sub-orientation is exhibited in a form close to the maximum, and the low stiffness of the rolled copper foil is obtained. Therefore, the rolled copper foil provided with the bending characteristic which was excellent with low stiffness can be obtained.

<Other Embodiments of the Present Invention>
As mentioned above, although embodiment of this invention was described concretely, this invention is not limited to the above-mentioned embodiment, It can change variously in the range which does not deviate from the summary.

  For example, in the above-described embodiment, Ag is used as the additive for adjusting the heat resistance of the rolled copper foil. However, the additive is not limited to those listed in Ag, the technical literature, and the like. Moreover, the various characteristics that can be adjusted by the additive are not limited to heat resistance, and the additive may be appropriately selected according to the various characteristics that require adjustment.

  In the above-described embodiment, the CCL process in the FPC manufacturing process also serves as a recrystallization annealing process for the rolled copper foil. However, the recrystallization annealing process may be performed as a separate process from the CCL process.

  Moreover, in the above-mentioned embodiment, although rolled copper foil was used for FPC use, the use of rolled copper foil is not restricted to this, It is used for the use which requires a high bending characteristic and low stiffness. it can. Also about the thickness of rolled copper foil, it is good also as more than 20 micrometers according to various uses including a FPC use.

  Further, in the above-described embodiment, the total degree of work in the final cold rolling step S50 is set to 90% or more to obtain excellent bending characteristics. However, low stiffness is obtained by adjusting the sub-oriented crystal plane. The technique can be used independently of this. That is, when low stiffness is mainly important and it is sufficient that a certain degree of bending property is obtained, the total degree of work in the final cold rolling process is less than 90% such as 85% and 70%, for example. It is good.

  In addition, in order to show the effect of this invention, not all the processes mentioned above are necessarily essential. The various conditions given in the above-described embodiment and examples described later are merely examples, and can be changed as appropriate.

  Next, examples according to the present invention will be described together with comparative examples.

(1) Production of rolled copper foil Rolling according to Examples 1 to 18 and Comparative Examples 1 to 18 is performed using oxygen-free copper to which Ag with a target concentration of 200 ppm is added, in the same procedure and manner as in the above-described embodiment. Made copper foil. That is, first, an ingot having a thickness of 150 mm and a width of 500 mm prepared by dissolving a predetermined amount of Ag in oxygen-free copper and casting was prepared. Table 2 below shows analysis values of Ag concentration in the ingot, which were analyzed by an inductively coupled plasma (ICP) emission spectroscopic analysis method.

As shown in Table 2, with respect to the target concentration of 200 ppm, the analytical values are 185 ppm to 210 ppm, both of which are suppressed to variations within about 200 ppm ± 20 ppm (10%). Originally, Ag may be contained in the oxygen-free copper as the main raw material in the order of several ppm to tens of ppm as an unavoidable impurity, and due to various causes such as variations in casting an ingot, ±
Variation within about 20 ppm is common in the metal material field.

  Next, after obtaining a plate material having a thickness of 8 mm in the hot rolling step by the same procedure and method as in the above-described embodiment, the cold rolling step and intermediate annealing for 2 minutes at a temperature of 700 ° C. to 800 ° C. A copper strip (fabric) was manufactured by repeatedly performing the process, and an annealed fabric was obtained in a fabric annealing process in which the temperature was maintained at 750 ° C. for 1 minute. Here, the temperature conditions of each annealing process match the heat resistance of the oxygen-free copper material containing 185 ppm to 210 ppm of Ag.

  Finally, the final cold rolling process was performed by the same procedure and method as the above-mentioned embodiment, and the rolled copper foil which concerns on Examples 1-18 and Comparative Examples 1-18 was obtained. The conditions in the final cold rolling process are shown in Table 3 below.

  As shown in Table 3, the final cold rolling was performed by changing the conditions as shown in the right column in accordance with the reduction of the plate thickness sequentially from the upper stage to the lower stage. That is, the degree of processing per pass and the position of the neutral point of the cold rolling process with a thickness of 200 μm or less were changed. The position (mm) of the neutral point shown in the right column is indicated by the length from the end on the outlet side of the contact surface between the roll and the annealed material as the workpiece to the neutral point. Further, in order to obtain excellent bending characteristics, the conditions were set so that the total degree of work in the final cold rolling process was 95% in all of Examples 1 to 18 and Comparative Examples 1 to 18. By the above, the rolled copper foil which concerns on Examples 1-18 and Comparative Examples 1-18 whose thickness is 12 micrometers was manufactured.

(2) Evaluation of rolled copper foil The following evaluation was performed about the rolled copper foil which concerns on Examples 1-18 manufactured as mentioned above and Comparative Examples 1-18.

(X-ray diffraction measurement by 2θ / θ method)
First, X-ray diffraction measurement by the 2θ / θ method was performed on the rolled copper foils according to Examples 1 to 18 and Comparative Examples 1 to 18. The measurement concerned is an X-ray diffractometer manufactured by Rigaku Corporation (model: Ult
ima IV) and the conditions shown in Table 4 below.

  Table 5 below shows diffraction peak intensities of the {022} plane, {002} plane, {113} plane, {111} plane, and {133} plane of the copper crystal measured by the 2θ / θ method.

  Further, Tables 6 and 7 below show the results of calculating each value by applying the diffraction peak intensity values in Table 5 to the proportional relational expressions of the above formulas (1) to (12).

As described above, in this example and the comparative example, the degree of processing per pass and the position of the neutral point in the final cold rolling process are changed. Thereby, at the time of cold rolling, the ratio of the stress component between the compression component and the tensile component applied to the workpiece is changed. As a result, the ratio of each crystal plane changes, and as shown in Tables 6 and 7, the ratio of the diffraction peak intensity of each crystal plane also changes.

  According to the combination of the conditions of Examples 1 to 18, all the values from the formulas (1) to (12) are within the above-mentioned predetermined range, and after the recrystallization annealing process, the low stiffness is excellent. It turns out that the rolled copper foil which can be provided with the bending characteristic which was able to be obtained is obtained. On the other hand, in the combination of the conditions of Comparative Examples 1 to 18, in any rolled copper foil, a plurality of values out of the values from the formulas (1) to (12) are outside the above-described predetermined range. This rolled copper foil cannot have low stiffness even after undergoing a recrystallization annealing process. In Table 7, values outside the above-mentioned predetermined range are shown in bold with underline.

(Bending fatigue life test)
Next, in order to examine the bending characteristics of each rolled copper foil, FPC high-speed bending tester (model: SEK-31B2S) manufactured by Shin-Etsu Engineering Co., Ltd. was used, and bending fatigue was performed in accordance with the IPC (American Printed Circuit Industry Association) standard. A life test was conducted. FIG. 2 shows a schematic diagram of a general sliding bending test apparatus 10 including the FPC high-speed bending tester and the like.

  First, a sample piece S obtained by cutting the rolled copper foils according to Examples 1 to 18 and Comparative Examples 1 to 18 into a width of 12.5 mm and a length of 220 mm was subjected to the same procedure and technique as in the above-described recrystallization annealing step. Recrystallization annealing was performed at 60 ° C. for 60 minutes. Such a condition imitates an example of the amount of heat that the rolled copper foil actually receives in close contact with the substrate in the CCL process of the printed wiring board.

  Next, as shown in FIG. 2, the rolled copper foil sample S was fixed to the sample fixing plate 11 of the sliding bending test apparatus 10 with screws 12. Subsequently, the sample S was brought into contact with the vibration transmission unit 13, and the vibration transmission unit 13 was vibrated in the vertical direction by the oscillation driver 14 to transmit the vibration to the sample S, and a bending fatigue life test was performed. The measurement conditions for the bending fatigue life were a bending radius of 1.5 mm, a stroke of 10 mm, and an amplitude number of 25 Hz. Under such conditions, five sample pieces S cut from each rolled copper foil were measured and their average values were compared. Table 8 below shows the results.

  As described above, each rolled copper foil has undergone a final cold rolling process in which the total degree of work is 95%, and as shown in Table 8, in any of Examples 1 to 18 and Comparative Examples 1 to 18 The bending fatigue life, that is, the number of bending breaks was 1 million times or more, and excellent bending characteristics were obtained.

(Evaluation of loop stiffness)
Subsequently, the stiffness of each rolled copper foil was investigated using a loop stiffness tester manufactured by Toyo Seiki Seisakusho Co., Ltd. FIG. 3 shows an outline of the test method.

  First, the recrystallization annealing for 60 minutes was performed to the sample piece S which cut the rolled copper foil which concerns on Examples 1-18 and Comparative Examples 1-18 in width 10mm and length 180mm similarly to the above. Next, as shown in FIG. 3, both ends of the sample piece S are combined to form a loop having a loop length of 70 mm, and then the sample piece S is sandwiched between the indenter plate 21 and the fixed plate 22 facing each other. The top of the loop was pushed toward the fixed plate 22 by the indenter plate 21 with a stroke of 5 mm. In the loop stiffness measurement, the compression force (repulsive force) at this time is measured. The method of measuring the stiffness by the loop stiffness is a technique that is widely used in the recent FPC industry, although it is not standardized as in the JIS standard and the IPC standard. The results are shown in Table 9 below.

  As shown in Table 9, the repulsive force (loop stiffness) of Examples 1 to 18 is 0.045 g to 0.056 g, indicating low repulsion. On the other hand, the repulsive force of Comparative Examples 1-18 is comparatively high with 0.067g-0.081g. The repulsive force in the whole Examples 1 to 18 is about 16% to 44% smaller than the whole Comparative Examples 1 to 18 ([(0.067-0.056) /0.067] × 100≈16%, [(0.081−0.045) /0.081] × 100≈44%).

  Thus, in the rolled copper foil which concerns on Examples 1-18 in which the ratio of the crystal plane of a sub-orientation was adjusted so that it may be seen in the proportionality relational expression to said formula (1)-(12), it is low stiffness. It can be seen that sex is obtained. On the other hand, in the rolled copper foil which concerns on Comparative Examples 1-18 in which the several value obtained by said Formula (1)-(12) was outside the predetermined range, sufficient low stiffness was not acquired. .

  As mentioned above, when combined with the results of the above-described bending fatigue life test, it is understood that the rolled copper foils according to Examples 1 to 18 have excellent bending characteristics as well as low stiffness by performing recrystallization annealing. On the other hand, although the rolled copper foil which concerns on Comparative Examples 1-18 is equipped with the outstanding bending characteristic, it is inferior to the stiffness property.

(3) Rolled copper foil using tough pitch copper Next, using a tough pitch copper to which Ag having a target concentration of 200 ppm was added, Example 19 having a thickness of 12 μm and the same procedure and method as in the above-described Examples and A rolled copper foil according to Comparative Example 19 was produced. The Ag concentrations in the ingots of Example 19 and Comparative Example 19 were 190 ppm and 195 ppm, respectively, as analytical values obtained by IPC emission spectroscopic analysis. In addition, according to the heat resistance of the tough pitch copper material containing Ag with such a concentration, only the intermediate annealing process and the dough annealing process were performed under conditions different from the above. Specifically, the intermediate annealing step was held at a temperature of 600 ° C. to 700 ° C. for about 2 minutes, and the dough annealing step was held at a temperature of 700 ° C. for about 1 minute.

  For the rolled copper foils according to Example 19 and Comparative Example 19 manufactured as described above, X-ray diffraction measurement was performed by the 2θ / θ method in the same manner and procedure as in the above-described Examples, and the obtained crystal planes were obtained. Each value was calculated by applying the diffraction peak intensity to the proportional relational expressions of the above formulas (1) to (12).

  For the rolled copper foil according to Example 19, the proportional relationship between the diffraction peak intensities of the crystal planes was within a predetermined range from Equations (1) to (12).

On the other hand, for the rolled copper foil according to Comparative Example 19, the numerical value according to Equation (2) is
(I _{002} + I _{113} ) / (I _{111} + I _{133} ) = 0.90
It was out of the predetermined range. As a result, other proportional relationships may be out of the predetermined range.

  Further, with respect to the rolled copper foil according to Example 19 and Comparative Example 19, a bending fatigue life test was performed by the same procedure and method as in the above-described example. As above, the total processing in the final cold rolling step was performed. Since the degree was 95%, both Example 19 and Comparative Example 19 exhibited excellent bending characteristics with a number of bending breaks of 1 million times or more.

  Further, with respect to the rolled copper foil according to Example 19 and Comparative Example 19, when the loop stiffness was evaluated by the same procedure and method as in the above Example, the repulsive force of Example 19 was 0.051 g. On the other hand, the repulsive force of Comparative Example 19 was 0.072 g. Therefore, also in the rolled copper foil of Example 19 which uses tough pitch copper as a raw material, low stiffness could be obtained.

(4) Rolled copper foil using different additives Next, using oxygen-free copper added with Ag (target concentration of 120 ppm) and titanium (Ti) with target concentration of 40 ppm as an additive, The rolled copper foil which concerns on Example 20 and Comparative Example 20 whose thickness is 12 micrometers was manufactured with the same procedure and method. The Ag concentrations in the ingots of Example 20 and Comparative Example 20 were analytical values obtained by IPC emission spectroscopic analysis, and were 120 ppm and 125 ppm, respectively. Ti concentrations were 37 ppm and 44 ppm, respectively. The variations are all within ± 10%, and are common in the field of metal materials.

  Also, different conditions from the above were used only in the intermediate annealing step and the dough annealing step in accordance with the heat resistance of the oxygen-free copper material containing Ag and Ti at the above concentrations. Specifically, the intermediate annealing step was held at a temperature of 650 ° C. to 700 ° C. for about 1 minute, and the dough annealing step was held at a temperature of 700 ° C. for about 1 minute.

  For the rolled copper foils according to Example 20 and Comparative Example 20 manufactured as described above, X-ray diffraction measurement was performed by the 2θ / θ method in the same manner and procedure as in the above-described Examples, and the obtained crystal planes were obtained. Each value was calculated by applying the diffraction peak intensity to the proportional relational expressions of the above formulas (1) to (12).

  About the rolled copper foil which concerns on Example 20, the proportional relationship of the diffraction peak intensity of each crystal plane became in the predetermined range to Formula (1)-(12).

On the other hand, for the rolled copper foil according to Comparative Example 20, the numerical value according to Equation (2) is
(I _{002} + I _{113} ) / (I _{111} + I _{133} ) = 0.95
It was out of the predetermined range. As a result, other proportional relationships may be out of the predetermined range.

  In addition, both the rolled copper foils according to Example 20 and Comparative Example 20 exhibited excellent bending characteristics with a bending breakage number of 1 million times or more in a bending fatigue life test using the same procedure and method as in the above-described Examples. .

  Furthermore, in the evaluation of loop stiffness by the same procedure and method as in the above-described Example, the repulsive force of Example 20 was 0.048 g, whereas the repulsive force of Comparative Example 20 was 0.074 g. . Therefore, low stiffness could be obtained also in the rolled copper foil of Example 20 to which different additives were added.

<Discussion by the present inventors>
As described above, the principle of low-stiffness is imparted to the rolled copper foil by controlling the sub-oriented crystal plane, and the control of the sub-oriented crystal plane in the above-described rolled copper foil manufacturing process. The inventors' consideration on the mechanism will be described below.

(1) Low Stiffness From the knowledge of crystal orientation, metallurgy, and previous experimental experience, the present inventors have learned about the principle that low stiffness can be obtained by controlling the crystal plane in the sub-orientation. The following considerations were made.

  According to the present inventors, it is considered that the low stiffness obtained in the present invention is related to the change of the main orientation and the non-change of the sub-direction before and after the recrystallization annealing process. As described above, in the recrystallization annealing step, the {022} plane that is the main orientation becomes the {002} plane after recrystallization. On the other hand, the {002} plane, {113} plane, {111} plane, and {133} plane, which are secondary orientations, remain substantially unchanged after recrystallization. It is considered that the close-packed surface is involved in low stiffness.

  Since the slip of the copper crystal is the movement of copper atoms, if the {111} plane, which is the slip plane of the copper crystal, is in a state parallel or nearly parallel to the rolling surface, the slip direction is also parallel or parallel to the rolling surface. It will be closer. Thereby, the repulsive force with respect to the force perpendicular to the rolling surface works in a direction perpendicular or nearly perpendicular to the slip direction, and it is considered that the repulsive force becomes stronger.

  On the other hand, the larger the angle formed between the sliding direction of the copper crystal and the rolling surface, the smaller the difference between the direction in which the repulsive force works and the sliding direction. That is, it is considered that as the angle formed by the direction of the repulsive force and the slip direction approaches in parallel, the repulsive force with respect to the force applied perpendicular to the rolling surface is more easily affected by the slip phenomenon of the copper crystal. Here, the angle formed by each crystal plane with respect to the {111} plane (slip plane) is as follows.

{111} face {002} face: 54.7 °
{111} face {113} face: 29.5 °, 58.5 °, 80.0 °
{111} face {133} face: 22.0 °
{111} face {022} face: 35.3 ° (reference value)

  That is, the slip surface of the copper crystal whose {002} plane is parallel to the rolling surface is located at 54.7 ° with respect to the rolling surface.

Moreover, the slip surface of the copper crystal whose {113} plane is parallel to the rolling surface is located at 29.5 °, 58.5 °, or 80.0 ° with respect to the rolling surface.

  Moreover, the sliding surface of the copper crystal whose {133} plane is parallel to the rolling surface is located at 22.0 ° with respect to the rolling surface.

  Further, the slip surface of the copper crystal whose {111} plane is parallel to the rolled surface is located at 0 ° with respect to the rolled surface.

  As described above, it is surmised that the balance between the angles formed by the crystal planes and the ratio of the diffraction peak intensities of the crystal planes affects the stiffness. Thus, it can be said that there is a close relationship between low stiffness and the ratio of crystal planes in each sub-orientation.

(2) Control of the crystal plane in the sub-direction (crystal rotation)
As described above, during the rolling process such as the final cold rolling process, the copper material is subjected to a compressive stress and a tensile stress that is weaker than the compressive stress. The copper crystal in the rolled copper material causes a rotation phenomenon to the {022} plane due to the stress during the rolling process, and with the progress of the rolling process, the orientation of the crystal plane parallel to the rolled plane is mainly the {022} plane. A rolling texture is formed. At this time, as described above, the path of rotation toward the {022} plane varies depending on the ratio of the compressive stress and the tensile stress. This will be described with reference to FIG.

  FIG. 4 is an inverse pole figure of a pure copper type metal quoted from the following technical document (d), (a) is an inverse pole figure showing a crystal rotation direction by tensile deformation, and (b) is by compression deformation. It is a reverse pole figure which shows a crystal rotation direction. In the inverted pole figure, the {002} plane is expressed as {001} plane and the {022} plane is expressed as {011} plane. That is, the {002} plane is represented by the {001} plane which is the minimum value of the plane parallel to the {002} plane, and the {022} plane is the minimum value of the plane parallel to the {022} plane. Express in terms of faces.

  (D) Editor Shinichi Nagashima, “Cross texture”, Maruzen Co., Ltd., January 20, 1984, p. 96, Figures 2.52 (a) and (c)

  As shown in FIG. 4, the copper crystal in the copper material rotates toward the {111} plane only by tensile deformation, and rotates toward the {011} plane only by compression deformation. In rolling, since the compression component and the tensile component are deformed, the crystal rotation direction is not so simple. However, since the compressive component prevails over the tensile component and deforms and is rolled, the crystal rotation toward the {011} plane generally takes place, and the {111} plane changes depending on the ratio of the compressive component and the tensile component. Also try to rotate partly. At this time, since the compression component is dominant, crystal rotation is also caused in which the crystal that has been rotated to the {111} plane returns to the {011} plane. On the contrary, when a crystal rotating toward the {011} plane or a crystal reaching the {011} plane rotates toward the {133} plane or the {111} plane due to the tensile component There is also.

  Thus, when crystal rotation occurs while the compression component and the tensile component coexist while maintaining the relationship of compression component> tensile component, the main orientation and sub-direction as shown in the reverse pole figure of FIG. It is thought that the orientation crystal plane distribution. Since the compression component> tensile component, the final main orientation crystal plane is the {011} plane, and as a result of crystal rotation by mixing the compression component and the tensile component, the sub-orientation crystal plane is {001} It is considered to be a plane, {113} plane, {111} plane, and {133} plane.

Here, FIG. 5 shows that only the crystal planes of the specific orientation are distributed, but this is due to the following reason. Since copper has a face-centered cubic crystal, X-ray diffraction measurement by the 2θ / θ method does not appear as a diffraction peak unless h, k, and l on the {hkl} plane are all odd or even values. This is because if h, k, and l are a mixture of odd and even values, the diffraction peak disappears due to the extinction rule and measurement is impossible. Therefore, in showing the configuration of the rolled copper foil according to the above-described embodiment etc., the {001} plane ({002} plane), {113} plane, {111} plane, and {133} plane appearing as diffraction peaks. Stipulated. Since the effect of this configuration is obvious from the results of the above-described Examples and the like, it can be said that it is sufficient to consider the sub-oriented crystal planes listed above.

(Control by processing degree)
From the above, assuming that compressive stress> tensile stress, adjusting the ratio of compressive component and tensile component changes the path of rotation toward the {022} plane. Specifically, the larger the compression component, the easier it is to pass through the {002} plane and {113} plane, and the greater the tensile component, the easier it is to pass through the {111} plane and {133} plane. The main sub-orientation crystal planes are {002} plane, {113} plane, {111} plane, and {133} plane because the crystal plane that could not be rotated to the {022} plane is a copper material. This is because the ratio of the crystal plane of each sub-orientation remaining in the copper material can be adjusted by adjusting the compression component and the tensile component in the final cold rolling step.

  Specifically, the compression component and the tensile component can be controlled by changing the rolling conditions per pass during the rolling process. In adjusting various control parameters for controlling the compression component and the tensile component, for example, attention can be paid to a change in the degree of processing per pass, as attempted in the above-described embodiments and examples.

  In order to increase the degree of processing per pass, for example, there is a method of crushing the copper material to be rolled by increasing the rolling load (roll load). In this case, the compressive stress increases. Therefore, the crystal rotation path becomes {002} plane or {113} plane and rotates toward the {022} plane.

  On the other hand, on the premise of compressive stress> tensile stress, there is also a method of increasing the workability by increasing the tensile component and thinning the copper material. Since the tensile component is increased, the crystal rotation path is the {111} plane or {133} plane and rotates toward the {022} plane. Note that the {133} plane remaining in the copper material after rolling is obtained by the tensile component and the crystal once reached the {022} plane by the compression component due to the tensile component. It is considered that it has been rotated again to the {133} plane. Further, the change in the degree of processing due to the tensile stress is small as compared with the case where the compressive load is increased. That is, the compressive stress has a larger contribution to the degree of processing.

  It should be noted that the material shape cannot be processed uniformly only by the respective components (compressive stress and tensile stress), and rolling cannot be performed. That is, the material shape is controlled at the same time as the thickness of the material is reduced by both compressive stress and tensile stress.

(Control by neutral point)
In the above-described embodiments and examples, the position control of the neutral point is also performed together with the degree of processing per pass in the final cold rolling process. That is, in adjusting the control parameters of the compression component and the tensile component, it is possible to pay attention to, for example, a change in the position of the neutral point.

  As described above, the control factors that control the position of the neutral point for each pass include the front tension, the rear tension, the rolling speed (roll rotational speed), the roll diameter, the working degree, the rolling load, and the like. Various combinations of these control factors can be used to change the position of the neutral point.

The position of such a neutral point can be calculated from some measured values. That is, first, the following formula with reference to the following technical document (e):
Tension component + compressive force component = 2 × shear yield stress (13)
In this relationship, the compression force component is made larger than the tension component, and further, the condition balance between the rolling speed and the roll diameter, that is, the position of the neutral point on the contact surface between the roll and the copper material at the time of rolling is expressed by the equation (13). ) To calculate. The details of the neutral point were also referred to the following technical document (e).

  (E) Edited by Japan Society for Technology of Plasticity, “Plastic Technology Series 7 Sheet Rolling”, Corona, p14, p27 formula (3.3), p28

  Although the parameter at the time of calculation of the above equation (13) is the control factor, a plurality of types of control methods are conceivable depending on how the fixed one and the variable one are selected. . In the above-described embodiments and examples, the position of the neutral point is controlled using the degree of machining as a variable control factor, but control using a control factor other than the degree of machining is also possible.

  The control factor is related to the configuration of the rolling mill, and the neutral point position control largely depends on the specifications of the rolling mill. Specifically, the compression stress is applied to the copper material due to differences in the number of rolls, the total number of rolls, the combination of rolls, and the roll configuration such as the diameter, material, and surface condition (surface roughness) of each roll. Difference in the direction and coefficient of friction. If the rolling mills are different, each control factor related to the conditions mentioned in the above embodiment also has different absolute values, and can be appropriately adjusted for each rolling mill.

DESCRIPTION OF SYMBOLS 10 Sliding bending test apparatus 11 Sample fixing plate 12 Screw 13 Vibration transmission part 14 Oscillation drive body 21 Indenter plate 22 Fixing plate S Sample piece

Claims (5)

A rolled copper foil comprising a main surface, after a final cold rolling step having a plurality of crystal planes parallel to the main surface, and before a recrystallization annealing step,
The plurality of crystal planes include {022} plane, {002} plane, {113} plane, {111} plane, and {133} plane,
The diffraction peak intensities of the crystal planes obtained by X-ray diffraction measurement by the 2θ / θ method with respect to the main surface are respectively I _{022} , I _{002} , I _{113} , I _{111} , and I _{{133 }}
I _{022} / (I _{022} + I _{002} + I _{113} + I _{111} + I _{133} ) ≧ 0.50,
(I _{002} + I _{113} ) / (I _{111} + I _{133} ) ≧ 1.0,
I _{022} / I _{002} ≦ 8.0,
I _{022} / I _{113} ≦ 30,
I _{022} / I _{111} ≧ 7.0,
I _{022} / I _{133} ≧ 10,
1.0 ≦ I _{002} / I _{113} ≦ 15,
I _{111} / I _{133} ≦ 10,
I _{113} / I _{111} ≧ 0.30,
1.0 ≦ I _{002} / I _{111} ≦ 20,
1.0 ≦ I _{002} / I _{133} ≦ 75, and
The rolled copper foil characterized by 0.50 ≦ I _{113} / I _{133} ≦ 20.   2. The rolled copper foil according to claim 1, wherein the thickness is 20 μm or less by the final cold rolling step with a total workability of 90% or more. The rolled copper foil according to claim 1 or 2, comprising oxygen-free copper having a purity of 99.96% or more or tough pitch copper having a purity of 99.9% or more as a main component. The rolled copper foil according to any one of claims 1 to 3, wherein at least one of silver, boron, titanium, and tin is added. It is an object for flexible printed wiring boards, The rolled copper foil in any one of Claims 1-4 characterized by the above-mentioned.

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