JP5373940B1 - Rolled copper foil - Google Patents

Abstract

An object of the present invention is to provide excellent bending resistance as well as high bending resistance.
A plurality of crystal planes parallel to the main surface include {022} plane, {002} plane, {113} plane, {111} plane, and {133} plane, and 2θ / θ with respect to the main surface. The diffraction peak intensity ratio of each crystal plane calculated from the X-ray diffraction measurement using the method and converted so that the total value becomes 100 is I _{022} + I _{002} ≧ 75.0, and X-ray In a graph plotting the average intensity of diffraction peaks on the {111} plane measured using the Pole-Figure method, the average intensities of diffraction peaks on the {111} plane at tilt angles of 47 ° and 53 ° are connected. The vertical axis intercept [A] of the straight line and the maximum value [B] of the average intensity of diffraction peaks on the {111} plane within the tilt angle range of 15 ° to 90 ° are [A] / [B] ≧ 1/4 and the surface roughness of the main surface is 10-point average roughness Rzjis ≦ 1 2 [mu] m, an arithmetic average roughness Ra ≦ 0.3 [mu] m.
[Selection] Figure 1

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.

A flexible printed circuit (FPC) is thin and excellent in flexibility, and thus has a high degree of freedom in mounting form on an electronic device or the like. For this reason, FPCs are not only for folding parts of foldable mobile phones, but also for moving parts such as digital cameras and printer heads, as well as hard disk drives (HDDs), digital versatile disks (DVDs), and compact disks (DVDs). It is often used for wiring of movable parts of disk related equipment such as CD (Compact Disk). Therefore, the rolled copper foil used as FPC and its wiring material has been required to have high bending properties, that is, excellent bending resistance that can withstand repeated bending.

  The rolled copper foil for FPC is manufactured through processes such as hot rolling and cold rolling. In the subsequent FPC manufacturing process, the rolled copper foil is bonded to an FPC base film (base material) made of a resin such as polyimide by heating or the like via an adhesive or directly. The rolled copper foil on the base material is subjected to surface processing such as etching to become a wiring. The bending resistance of the rolled copper foil is significantly improved in the state after annealing softened by recrystallization than in the hard state after cold rolling that has been rolled and hardened. Therefore, for example, in the manufacturing process of the FPC described above, the rolled copper foil is cut using the rolled copper foil after cold rolling while avoiding deformation such as elongation and wrinkles, and is superimposed on the substrate. Thereafter, the rolled copper foil and the base material are brought into close contact with each other by heating while also serving as recrystallization annealing of the rolled copper foil.

  On the premise of the above-mentioned FPC manufacturing process, various studies have been made so far on a rolled copper foil excellent in bending resistance and its manufacturing method, and the {002} plane ({200) having a cubic orientation on the surface of the rolled copper foil. } Surface) has been reported to improve the flex resistance.

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. Further, the rolling degree in the final cold rolling is set to 90% or more. As a result, in a state of being tempered to have a recrystallized structure, the strength of the {200} plane obtained by X-ray diffraction of the rolled surface is I, and the {200} plane obtained by X-ray diffraction of fine powder copper is I. When the intensity is 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, and the degree of processing in the final cold rolling is set to 93% or more. Further, by performing recrystallization annealing, a rolled copper foil having a remarkably developed cubic texture with an integral strength of {200} plane of I / I ₀ ≧ 40 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%. Thereby, a predetermined crystal grain orientation state is obtained after recrystallization annealing. That is, 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. Further, the ratio between the normalized diffraction peak intensity [a] of the {200} plane which is a cubic texture in the rolled surface and the normalized diffraction peak intensity [b] of the crystal region in the twin relation of the {200} plane. Is [a] / [b
] ≧ 3.

Thus, in the prior art, by increasing the total degree of work in the final cold rolling process, the cube texture of the rolled copper foil is developed after the recrystallization annealing process, thereby improving the bending resistance.

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

  On the other hand, in recent years, with the downsizing and thinning of electronic devices, the FPC is often folded and incorporated in a small space. In particular, in a panel portion of a smartphone or the like, an FPC in which wiring is formed may be folded at 180 ° and incorporated. For this reason, the request | requirement of the bending resistance which accept | permits a small bending radius is increasing with respect to rolled copper foil.

  In this way, depending on the application and the like, different demands may arise between bending resistance that can withstand repeated bending and bending resistance that can withstand a small bending radius. In order to meet these different requirements, conventionally, rolled copper foils having different characteristics have been separately manufactured for each application. However, such a situation is not efficient in terms of productivity, and there is a problem that profitability is poor.

  An object of the present invention is to provide a rolled copper foil that can be provided with excellent bending resistance as well as high bending resistance after the recrystallization annealing step. As described above, if a rolled copper foil having both characteristics can be realized, it can be applied to both uses that place importance on bending resistance and uses that place importance on bending resistance. Therefore, production efficiency can be remarkably improved both in the production of rolled copper foil and in the production of FPC.

According to a first aspect of the invention,
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 intensity ratios of the crystal planes obtained by X-ray diffraction measurement using the 2θ / θ method with respect to the main surface and converted so that the total value becomes 100 are I _{022} and I _{002} , respectively _. , I _{113} , I _{111} , and I _{133} ,
I _{022} + I _{002} ≧ 75.0,
Using X-ray Pole-Figure method, for each of a plurality of tilt angles within a range of 15 ° to 90 °, the in-plane rotation angle of the main surface is changed within a range of 0 ° to 360 °. The average intensity of the diffraction peaks of the {111} plane
When creating a graph plotting the average intensity of diffraction peaks of the {111} plane with the tilt angle as the horizontal axis and the diffraction peak intensity as the vertical axis,
A vertical axis intercept of a straight line connecting the average intensity of the diffraction peak of the {111} plane at the tilt angle of 47 ° and the average intensity of the diffraction peak of the {111} plane at the tilt angle of 53 ° is [A When the maximum value of the average intensity of the diffraction peaks of the {111} plane in the range where the tilt angle is 15 ° or more and 90 ° or less is [B],
[A] / [B] ≧ 1/4,
The surface roughness of the main surface is
Ten-point average roughness Rzjis ≦ 1.2 μm,
A rolled copper foil having an arithmetic average roughness Ra ≦ 0.3 μm is provided.

According to a second aspect of the invention,
The rolled copper foil as described in the 1st aspect which has oxygen-free copper or tough pitch copper as a main component is provided.

According to a third aspect of the invention,
The rolled copper foil as described in the 1st or 2nd aspect to which at least any one of silver, boron, titanium, and tin is added is provided.

According to a fourth aspect of the invention,
The rolled copper foil in any one of the 1st-3rd aspect which is 20 micrometers or less in thickness is provided.

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

  ADVANTAGE OF THE INVENTION According to this invention, the rolled copper foil which can be equipped with the outstanding bending resistance with high bending resistance after a recrystallization annealing process is provided.

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 figure which shows the outline | summary of the measuring method of the X-ray diffraction in the Example and comparative example of this invention. It is a measurement result of X-ray diffraction using 2θ / θ method, (a) is an X-ray diffraction chart of a rolled copper foil according to Example 1 of the present invention, (b) is a rolling according to Example 2. It is an X-ray diffraction chart of copper foil, (c) is an X-ray diffraction chart of the rolled copper foil which concerns on the comparative example 3. FIG. It is the graph produced by plotting the average intensity | strength of the diffraction peak of the {111} surface which concerns on Example 1 of this invention. It is the graph produced by plotting the average intensity | strength of the diffraction peak of the {111} surface which concerns on Example 2 of this invention. It is the graph produced by plotting the average intensity | strength of the diffraction peak of the {111} surface which concerns on Example 3 of this invention. It is the graph produced by plotting the average intensity | strength of the diffraction peak of the {111} surface which concerns on Example 4 of this invention. 6 is a graph created by plotting the average intensity of diffraction peaks on the {111} plane according to Comparative Example 1. 10 is a graph created by plotting the average intensity of diffraction peaks on the {111} plane according to Comparative Example 2. 14 is a graph created by plotting the average intensity of diffraction peaks on the {111} plane according to Comparative Example 3. 10 is a graph created by plotting the average intensity of diffraction peaks on the {111} plane according to Comparative Example 4. 10 is a graph created by plotting the average intensity of diffraction peaks on the {111} plane according to Comparative Example 5. 14 is a graph created by plotting the average intensity of diffraction peaks on the {111} plane according to Comparative Example 6. 14 is a graph created by plotting the average intensity of diffraction peaks on the {111} plane according to Comparative Example 7. It is a schematic diagram of the sliding bending test apparatus which measures the bending resistance 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 bending resistance 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. FIG. 6 is a diagram in which a {013} plane, a {023} plane, and a crystal plane region having a relatively small orientation difference from these crystal planes are added to a general inverted pole figure.

<Knowledge obtained by the present inventors>
As described above, in order to obtain a rolled copper foil having excellent bending resistance 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 the subsequent recrystallization annealing step, the {002} plane, that is, the cube orientation and It was confirmed that That is, it is preferable that the {022} plane is the main orientation after the final cold rolling step and before the recrystallization annealing step.

  On the other hand, as described in Patent Documents 1 to 3 mentioned above, and as tried by the present inventors, even if a large number of cube textures are expressed, cube assembly in a rolled copper foil having a polycrystalline structure The {002} plane that is the organization does not occupy 100%. This is the same even before the recrystallization annealing process. In addition to the {022} plane which is the main orientation before the recrystallization annealing process and the {002} plane where the crystal orientation is maintained before and after the recrystallization, {113 }, {111} planes, {133} planes, {013} planes, {023} planes and other sub-orientation crystal planes are mixed together without being controlled. And it is thought that the crystal grain which has these several crystal planes has various influences on the various characteristics of a rolled copper foil. Therefore, the present inventors focused on the sub-oriented crystal planes that have been made unnecessary so far, while maintaining high bending resistance without reducing the occupancy of the main orientation, It has been investigated whether other characteristics such as rolled copper foil can be improved, for example, bending resistance, which has been increasing in demand in recent years.

  In such examination, the inventors of the present invention determined that the main surface of the rolled copper foil is a crystal plane including sub-orientations such as {113} plane, {111} plane, {133} plane, {013} plane, {023} plane, etc. The analysis of diffraction peaks at has been advanced. The diffraction peak indicates the presence of each sub-azimuth, and the occupation ratio of each sub-azimuth can be known from the intensity ratio. As a result of such diligent research, the present inventors have specified various states of diffraction peaks, and by controlling these, high bending resistance has already been obtained by controlling the {022} plane of the main orientation. It was found that the bending resistance can be further improved even under the circumstances.

  At the same time, the present inventors have further conducted intensive studies to obtain a rolled copper foil having high bending resistance required for FPC applications. As a result, it was found that not only the crystal orientation but also the unevenness of the main surface of the rolled copper foil had a great influence on the bending resistance.

  The present invention is based on these 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.

(Outline of rolled copper foil)
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 has a predetermined thickness by subjecting an ingot made of pure copper such as oxygen-free copper (OFC) or tough pitch copper to a hot rolling process or a cold rolling process, which will be described later. The rolled copper foil after the final cold rolling process and before the recrystallization annealing process.

  The rolled copper foil according to the present embodiment has a thickness of 20 μm by a final cold rolling process with a total workability of 90% or more, more preferably 94% or more so that it can be used for flexible wiring materials such as FPC. It is structured as follows. After that, the rolled copper foil is subjected to a recrystallization annealing process, for example, which also serves as a bonding process with a base material of FPC as described above, and has excellent bending resistance by recrystallization. Is contemplated.

  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. Further, tough pitch copper is a copper material having a purity specified in, for example, JIS C1100, H3100, etc. of 99.9% or more. In the case of tough pitch copper, the oxygen content is, for example, about 100 ppm to 600 ppm. In some cases, a small amount of a predetermined additive such as silver (Ag) is added to these copper materials to form a diluted copper alloy, and a rolled copper foil in which various properties such as heat resistance are adjusted. The rolled copper foil according to the present embodiment can contain both pure copper and dilute copper alloy, and the influence of the present embodiment on the effect of the present embodiment by the copper material and the additive material 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 excellent bending resistance can be obtained.

(Crystal structure of rolled surface)
Moreover, the rolled copper foil which concerns on this embodiment has several crystal planes parallel to a rolling 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. The {022} plane is the main orientation in the rolling plane, and the other crystal planes are sub-azimuths.

  As described above, the state of each crystal plane is controlled by a proportional relational expression that defines the state of diffraction peak intensity and the like measured for each crystal plane. The diffraction peak intensity of each crystal plane can be determined from X-ray diffraction measurement using the 2θ / θ method with respect to the rolled surface of the rolled copper foil. Here, an outline of X-ray diffraction measurement using the 2θ / θ method will be described with reference to FIG. 2 relating to an example and a comparative example described later. Details of the X-ray diffraction measurement will be described later.

  As shown in FIG. 2, a sample piece 50 such as a rolled copper foil is disposed so as to be rotatable around three scanning axes of the θ axis, the ψ axis, and the φ axis. In X-ray diffraction measurement using the 2θ / θ method, the sample piece 50 is rotated about the θ axis, and incident X-rays are incident on the sample piece 50 at an angle θ. Further, diffracted X-rays diffracted at an angle 2θ with respect to the incident direction of incident X-rays are detected. Thereby, the diffraction peak of each crystal plane parallel to the main surface of the sample piece 50 is obtained with the intensity | strength according to the occupation rate of each crystal plane in the main surface.

The diffraction peak intensity ratios I _{022} and I _{{of the} respective crystal planes are obtained by converting the diffraction peak intensities of the five crystal planes measured by X-ray diffraction into a ratio such that the total value becomes 100. _002} , I _{113} , I _{111} , and I _{133} . The diffraction peak intensity ratio is substantially equal to the occupancy ratio of each crystal plane on the rolled surface.

A conversion formula (A) for obtaining the diffraction peak intensity ratio of the {022} plane as a representative from the diffraction peak intensity of each crystal plane is shown below. Here, it is assumed that the diffraction peak intensities of the crystal planes are I ' _{022} , I' _{002} , I ' _{113} , I' _{111} , and I ' _{133} , respectively.

  In the rolled copper foil according to the present embodiment, the diffraction peak intensity ratio between the {022} plane and the {002} plane is such that the following formula (1) holds.

I _{022} + I _{002} ≧ 75.0 (1)

  Moreover, the rolled copper foil which concerns on this embodiment is prescribed | regulated so that the numerical value calculated | required using the X-ray Pole-Figure (pole figure) method may be satisfy | filled in addition to the above-mentioned Formula (1). Here, the outline of the measurement using the X-ray Pole-Figure method will be described with reference to FIG. Details of the measurement will be described later.

  As shown in FIG. 2, in the measurement using the reflection method of the X-ray Pole-Figure method, the sample piece 50 described above is further rotated around the ψ axis, and a plurality of tilt angles within a range of 15 ° to 90 ° are obtained. Diffraction X-rays are detected for each of ψ as in the 2θ / θ method. At this time, each tilt angle ψ is measured by maintaining the angle and rotating the sample piece 50 around the φ axis to change the in-plane rotation angle φ within the range of 0 ° to 360 °. And the average intensity of diffraction peaks on the {111} plane of the obtained copper crystal is obtained.

  A method for defining the rolled copper foil according to the present embodiment using each average strength obtained by such measurement will be described below.

  With the tilt angle ψ as the horizontal axis and the diffraction peak intensity as the vertical axis, the above-mentioned {111} plane diffraction peak average intensity is plotted, for example, to create a graph as shown in FIG.

  For example, as shown in FIG. 4, the average intensity of the diffraction peak on the {111} plane when the tilt angle ψ is 47 ° and the average intensity of the diffraction peak on the {111} plane when the tilt angle ψ is 53 ° are linear. tie. Thereby, the vertical axis intercept of this straight line is obtained. At this time, the vertical axis intercept is [A].

  In addition, the maximum value of the average intensity of the diffraction peaks on the {111} plane within the graph range, that is, within the range where the tilt angle ψ is 15 ° or more and 90 ° or less is defined as [B]. At this time, in the rolled copper foil which concerns on this embodiment, the following formula | equation (2) is satisfy | filled.

      [A] / [B] ≧ 1/4 (2)

  As described above, by satisfying the conditions defined by the formulas (1) and (2), the rolled copper foil according to the present embodiment has a small bending with high bending resistance to withstand repeated bending after the recrystallization annealing process. Constructed to have excellent folding resistance to withstand the radius.

(Roughness of the rolled surface)
The rolled copper foil according to the present embodiment further has the following surface roughness in addition to the above-described configuration.

In the rolled copper foil according to this embodiment, the surface roughness of the rolled surface is defined by the ten-point average roughness Rzjis and the arithmetic average roughness Ra as shown in the following formulas (3) and (4). .

Ten-point average roughness Rzjis ≦ 1.2 μm (3)
Arithmetic average roughness Ra ≦ 0.3 μm (4)

  The ten-point average roughness and the arithmetic average roughness referred to here are a ten-point average roughness Rzjis and an arithmetic average roughness Ra respectively defined by JIS B 0601: 2001. There is a transition in the display symbols for the surface roughness defined in each JIS standard, and a slight confusion is likely to occur. As a precaution, Table 1 below shows the transition of JIS standards for surface roughness.

  The ten-point average roughness Rzjis and the arithmetic average roughness Ra are obtained from a roughness curve obtained by roughness measurement.

  That is, for the ten-point average roughness Rzjis, first, a reference length is extracted from the roughness curve in the direction of the average line. A predetermined number of peaks and valleys are measured in the direction of the vertical magnification from the average line of the extracted portions. At this time, the sum of the average value of the absolute values of the altitudes of the tops from the highest peak to the fifth and the average value of the absolute values of the altitudes of the bottoms from the lowest valley to the fifth is obtained. The ten-point average roughness Rzjis represents the sum of these average values in micrometers (μm).

  For the arithmetic average roughness Ra, the absolute value of the deviation from the average line extracted from the roughness curve to the measurement curve is summed to obtain the average value. That is, the arithmetic average roughness Ra is obtained by expressing the average value obtained by dividing the area obtained by the roughness curve and the average line by the length L in micrometers (μm).

  As described above, the rolled copper foil according to the present embodiment is configured to have excellent bending resistance as well as high bending resistance after the recrystallization annealing step.

(2) Properties imparted to the rolled copper foil The properties to be imparted to the rolled copper foil by providing the crystal structure and surface roughness as described above will be described below.

(Regarding the crystal structure defined by the formula (1))
As described above, the {022} plane before the recrystallization annealing process changes to the {002} plane after the recrystallization annealing process, and the {002} plane before the recrystallization annealing process remains after the recrystallization annealing process. This improves the bending resistance of the rolled copper foil. In the recrystallization annealing process, the {002} plane does not change its crystal orientation, but becomes a seed crystal and promotes the growth of the {022} plane changing to the {002} plane. Therefore, by satisfying the above formula (1) before the recrystallization annealing step, such an effect can be sufficiently obtained.

However, here, the {002} plane may not exist. That is, the diffraction peak intensity ratio I _{002} of the {002} plane may be zero. In the above formula (1), for example, I _{022} + I _{002} = 80.0 + 0 = 80.0 and I _{022} + I _{002} = 60.0 + 20.0 = 80.0 Thus, after the recrystallization annealing step, it is known that substantially the same rolled copper foils having a {002} plane crystal structure can be obtained. Moreover, the numerical value prescribed | regulated by the above-mentioned Formula (1) is so good that it is high, and the upper limit is not recognized so far.

(Regarding the crystal structure defined by the formula (2))
In addition, the present inventors have also conducted research on sub-directions other than the above-described crystal planes and have come to specify a sub-direction that is advantageous for bending resistance.

  That is, for example, the {013} plane, the {023} plane, or crystal orientations close to these crystal planes, specifically, crystal planes having crystal orientations within about ± 10 ° with these crystal planes are not bent. Has the effect of improving the performance. Further, the crystal orientation of these crystal faces does not change even after recrystallization in the recrystallization annealing step. Therefore, also about these crystal planes, if the state in the rolled copper foil after the final cold rolling step and before the recrystallization annealing step can be controlled, excellent bending resistance can be imparted to the rolled copper foil.

  By the way, the {013} plane and the {023} plane are not detected by X-ray diffraction measurement by the 2θ / θ method even if they exist on the rolled surface of the rolled copper foil. 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 the diffraction peak disappears due to the extinction rule when h, k, and l are a mixture of odd and even values such as the {013} plane and the {023} plane.

  Therefore, in the present embodiment, these crystal planes are defined as in the above formula (2) using the X-ray Pole-Figure method. In the above description, the diffraction peak of the {111} plane when the tilt angle ψ is 47 ° means the presence of a {013} plane parallel to the rolled surface of the rolled copper foil. Further, the state of the {013} plane can be known from the average intensity of the diffraction peaks. Further, the diffraction peak of the {111} plane at a tilt angle ψ of 53 ° means the presence of a {023} plane parallel to the rolled surface of the rolled copper foil. The state of the {023} plane can be known from the average intensity of the diffraction peaks.

  When the straight line in the graph of the average intensity of the diffraction peaks satisfies the above-described formula (2), a rolled copper foil having a sufficiently high occupancy ratio of these crystal faces can be obtained, and excellent bending resistance can be imparted. Whether or not such a straight line satisfies the above formula (2) is, for example, the magnitude relationship between the average intensity of the diffraction peak when the tilt angle ψ is 47 ° and the average intensity of the diffraction peak when the tilt angle ψ is 53 °, It is determined by the magnitude relationship between these average intensities and the average intensity of the maximum value of the graph, the slope of a straight line connecting the two average intensities, and the like.

  Moreover, the present inventors consider as follows that the bending resistance is imparted to the rolled copper foil by satisfying the above formula (2) using the graph of the average intensity of the diffraction peaks. . When the {013} plane, {023} plane, and crystal orientations close to these crystal planes, that is, crystal planes having a relatively small difference in crystal orientation with these crystal planes, are present in a predetermined amount in the rolled copper foil Is considered to form a texture. Moreover, it is thought that these crystal planes contribute to improvement of bending resistance by forming a texture.

  The condition that the vertical axis intercept [A] of the straight line obtained by the above-mentioned graph is ¼ of the maximum value [B] of the graph represents the boundary of whether these crystal planes form a texture. The present inventors think. That is, when [A] / [B] <1/4, the {013} plane, the {023} plane, etc. do not form a texture, or the formation is insufficient and the above-described effects are not exhibited. It is done. [A] / [B] defined by the above equation (2) is better as it is higher, and no upper limit value has been recognized so far.

(Surface roughness specified by formulas (3) and (4))
As described above, the present inventors, in addition to controlling the diffraction peak intensity ratio of each crystal plane, when the surface roughness of the rolled copper foil is not more than a predetermined value, the bending resistance of the rolled copper foil I found that I can improve. This is presumably because if the unevenness of the rolling surface of the rolled copper foil is large, the rolled copper foil is deformed in the direction in which the recess is opened when the rolled copper foil is bent, and cracks are likely to occur from this point.

  Initially, the present inventors decided to prescribe | regulate the surface roughness of rolled copper foil by 10-point average roughness Rzjis. By suppressing this to a predetermined value or less, the bending resistance of the rolled copper foil can be improved.

  However, only by controlling the ten-point average roughness Rzjis, the bending resistance varies for each sample piece for the measurement test, and the excellent bending resistance may not be stably obtained.

  As a result of further diligent research, the present inventors have defined the surface roughness using the arithmetic average roughness Ra in addition to the ten-point average roughness Rzjis, and by controlling these, the excellent bending resistance is stable. I found out that I could get it. The present inventors have considered the following reasons in view of the characteristics of various surface roughness indices as shown in Table 1 above.

  The maximum height Rz according to JIS B 0601: 2001 shown in Table 1 above is represented by the difference between the most convex part and the most concave part. Therefore, no matter how flat the other portion is, if there is a large protruding portion or a depressed portion, the maximum height Rz becomes large.

  The ten-point average roughness Rzjis used as one of the indices of the surface roughness of the rolled copper foil according to the present embodiment is quantified by extracting the difference of five points each including the most convex part and the most concave part. It is a thing. In other words, since it is digitized using a total of 10 points of the summit and the valley bottom, not only one unevenness difference as in the above-mentioned maximum height Rz, but information on how much unevenness difference is on average can be obtained. .

  On the other hand, the arithmetic average roughness Ra, which is another index of the surface roughness of the rolled copper foil, differs from the ten-point average roughness Rzjis, which focuses on the unevenness difference, how much undulation is present in the entire measurement location, Pay attention to. In other words, it is how far the roughness curve deviates from the central linear average line, and the area between the average line that is the average of the whole and the roughness of the roughness curve is seen. . Therefore, even if the maximum height Rz is large, the arithmetic average roughness Ra may be small if there is only one portion that protrudes greatly. In addition, even if each of the five points of the maximum uneven portion is substantially equivalent and the ten-point average roughness Rzjis is the same between the rolled copper foils, if there is surface roughness or the like in other portions, the arithmetic average roughness Ra is May be larger. On the other hand, if the surface roughness of the other part is within the range of 5 points of the maximum uneven part, the arithmetic average roughness Ra may be small.

According to the inventors, in view of the above, by controlling the ten-point average roughness Rzjis within a predetermined value, an extremely large unevenness difference is eliminated, and the unevenness portion is obtained when the rolled copper foil is bent. Can be prevented from breaking and breaking. On the other hand, by controlling the arithmetic average roughness Ra within a predetermined value, it is possible to suppress variation as a whole and to stabilize the value of the bending resistance.

  As described above, according to the present embodiment, excellent bending resistance is achieved by the internal control of the rolled copper foil that is manifested in an X-ray diffraction peak or the like such as 2θ / θ method or X-ray Pole-Figure method. And bending resistance can be imparted to the rolled copper foil. Moreover, by further controlling the outer surface of the rolled copper foil that is manifested in the surface roughness of the ten-point average roughness Rzjis and the arithmetic average roughness Ra, it is possible to stably impart further excellent bending resistance to the rolled copper foil. Can do.

(3) 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, casting is performed using pure copper such as oxygen-free copper (OFC) or tough pitch copper as a raw material to prepare an ingot. The ingot is formed in a plate shape having a predetermined thickness and a predetermined width, for example. Pure copper such as oxygen-free copper or tough pitch copper as a raw material may be a dilute copper alloy to which a predetermined additive is added in order to adjust various properties of the rolled copper foil.

  Various characteristics that can be adjusted with the additive include, for example, heat resistance. As described above, in the rolled copper foil for FPC, the recrystallization annealing step for imparting high bending resistance to the rolled copper foil is performed, for example, also as a bonding step with the 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.

  Examples of ingots used in the present embodiment are ingots having no additive added thereto, and ingots to which several kinds of additives are added are shown in Table 2 below.

  Further, as additives shown in Table 2 and other additives, for example, boron (B), niobium (Nb), titanium (Ti), nickel (about 10 ppm to 500 ppm) can be used as an additive for increasing or decreasing the heat resistance. There is an example in which one or more elements of Ni), zirconium (Zr), vanadium (V), manganese (Mn), hafnium (Hf), tantalum (Ta), and calcium (Ca) are added. Alternatively, there is an example in which Ag is added as the first additive element and any one or more of these elements listed as representative examples are added as the second additive element. In addition, chromium (Cr), zinc (Zn), gallium (Ga), germanium (Ge), arsenic (As), Cd (cadmium), indium (In), tin (Sn), antimony (Sb), gold (Au) ) Etc. can also be added in small amounts.

  Note that the composition of the ingot is maintained substantially as it is in the rolled copper foil after the final cold rolling step S40 described later, and when an additive is added to the ingot, the ingot and the rolled copper foil Have substantially the same additive concentration.

Moreover, the temperature conditions in the below-mentioned annealing process S32 are suitably changed according to the heat resistance by a copper material or an additive. However, such a change in the temperature condition of the copper material or additive and the annealing step S32 according to the copper material or the additive hardly affects 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 annealing step S32 are repeatedly performed a predetermined number of times. That is, work hardening is eased by subjecting a plate material 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.

  In addition, in the repetition process S30, the annealing process S32 in the middle of the repetition is referred to as an “intermediate annealing process”. Further, the annealing step S32 performed at the end of the repetition, that is, immediately before the final cold rolling step S40 described later is referred to as a “final annealing step” or a “dough annealing step”. In the dough annealing step, dough annealing is performed on the copper strip (fabric) to obtain an annealed dough. Also in the dough annealing step, the temperature condition is appropriately changed according to the heat resistance of the copper material. At this time, the dough annealing step is preferably performed under a temperature condition that can sufficiently relieve the processing strain caused by each of the above-described steps, for example, a temperature condition substantially equivalent to a complete annealing treatment.

(Final cold rolling process S40)
Next, the final cold rolling step S40 is performed. The final cold rolling is also called finish cold rolling, and the cold rolling to be finished is applied to the annealed fabric a plurality of times to form a thin copper foil. At this time, the total workability is set to 90% or more, more preferably 94% or more so that a rolled copper foil having high bending resistance can be obtained. Thereby, after the recrystallization annealing process, it becomes a rolled copper foil in which more excellent bending resistance can be easily obtained.

  Further, as described below, the degree of processing per one (one pass) of cold rolling that is repeated a plurality of times, the movement of the position of the neutral point, the surface roughness of the roll used for rolling, and the like are controlled, and cooling is performed. The compressive stress and tensile stress acting on the annealed fabric during cold rolling are changed. Thereby, the diffraction peak intensity ratio of each crystal plane of the rolled copper foil can be changed.

That is, it is preferable that the degree of processing per pass is gradually reduced 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 above-described example of the total degree of processing, and the thickness of the workpiece before rolling of the nth pass is T _Bn, and the thickness of the workpiece after rolling is T B _Assuming that _An is a degree of processing per pass (%) = [(T _Bn −T _An ) / T _Bn ] × 100.

  At the time of rolling, an object to be processed such as an annealed dough is reduced in thickness by, for example, being drawn into a gap between a pair of opposing rolling rolls and drawn to the opposite side. The speed of the workpiece is slower than the rotational speed of the rolling roll on the entrance side before being drawn into the rolling roll, and faster than the rotational speed of the rolling roll on the exit side after being drawn out from the rolling 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 ratio of each stress component (compression component and tensile component) on the premise that compression stress> tensile stress.

In the final cold rolling step S40, it is preferable to control the position of the neutral point described below to move toward the exit side of the rolling roll every time cold rolling is repeated a plurality of times. As described above, the speed of the workpiece whose magnitude relationship is reversed between the entrance side and the exit side with respect to the rotational speed of the rolling roll is the rotational speed of the rolling roll at some position between the entrance side and the exit side. Is equal to The 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 front tension, rear tension, rolling speed (rolling roll rotation speed), rolling roll diameter, rolling roll surface roughness, processing degree, rolling load, and the like. it can. That is, the ratio between the compressive stress and the tensile stress can be adjusted also by controlling the position of the neutral point.

  In the final cold rolling step S40, it is preferable to use a rolling roll having a surface roughness of 0.075 μm or less in terms of arithmetic average roughness Ra. The surface roughness of the rolling roll affects the stress balance between the compression stress and the tensile stress and the surface roughness of the rolled copper foil. Therefore, the ratio of each crystal plane can be controlled by controlling the surface roughness of the rolling roll to a predetermined value. Moreover, the rolled copper foil whose surface roughness satisfy | fills said formula (3), (4) can be obtained.

  At this time, it is preferable to adjust the surface roughness of the rolling roll to a predetermined value after appropriately adjusting the oil film equivalent. The oil film equivalent is an index related to the thickness of the oil film of the rolling oil applied to the workpiece. The oil film equivalent will be described later.

  The stress balance between the compressive stress and the tensile stress in the final cold rolling step S40 is controlled by the degree of processing per pass, the position shift of the neutral point, the surface roughness of the rolling roll, and the like. Further, the balance of the diffraction peak intensity of each crystal plane is mainly determined by the stress balance between the compressive stress and the tensile stress in the final cold rolling step S40.

  Specifically, during the rolling process such as the final cold rolling step S40, 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 in several paths. The greater the compressive stress, the easier it is to go through the {013} plane and {023} plane, and the greater the tensile stress, the easier it is to go through the {111} plane. And each changes to the {022} plane. A crystal that has not reached the {022} plane or a crystal that has reached the {022} plane but has been rotated to the {111} plane by the tensile stress is the sub-orientation.

  Thus, by changing the stress balance between the compressive stress and the tensile stress, the path of change to the {022} plane is changed, and the balance of the diffraction peak intensities of the sub-oriented crystal planes can be adjusted. The balance of the diffraction peak intensity of the crystal plane has a great influence on the bending resistance and bending resistance of the rolled copper foil as described above.

  As described above, by performing the final cold rolling step S40 while performing control of the degree of processing in each pass, position control of the neutral point, control of the surface roughness of the rolling roll, etc., the above formula (1 ) And (2) can be obtained. Further, the above-described surface roughness defined by the ten-point average roughness Rzjis and the arithmetic average roughness Ra is a predetermined value. Therefore, after the recrystallization annealing step, a rolled copper foil having high bending resistance that can withstand repeated bending and excellent bending resistance that can withstand a small bending radius can be obtained.

(Surface treatment step S50)
A predetermined surface treatment is applied to the fabric that has been formed into a copper foil through the above steps. The rolled copper foil which concerns on this embodiment is manufactured by the above.

(4) 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 an adhesive is not used, the rolled copper foil and the substrate are brought into direct contact with each other by heating and pressing. The heating temperature and time can be appropriately selected according to the curing temperature of the adhesive and the base material, and can be set to 1 to 120 minutes at a temperature of 150 to 400 ° 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 heating in the CCL process. 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. A rolled copper foil having a recrystallized structure is obtained by subjecting the rolled copper foil to a recrystallization annealing step.

  That is, most of the {022} plane that was the main orientation and the {002} plane that was the sub-azimuth before the recrystallization annealing process are {002} planes that are both tempered into a recrystallized structure. Thereby, high bending resistance is obtained.

  Further, the other sub-orientations are tempered into a recrystallized structure with almost no change while maintaining the state after the final cold rolling process even after recrystallization. However, by being in the recrystallized state, the influence of work hardening is removed from the crystal planes of these sub-orientations, and the action of the crystal planes of these sub-orientations appears in a form close to the maximum.

  For example, the effect of improving the bending resistance of the {013} plane and the {023} plane is exhibited. At this time, the {013} plane and the {023} plane are in a state where the occupation ratio is sufficiently high depending on the condition obtained from the above equation (2).

  In addition, since the surface roughness defined by the above-mentioned ten-point average roughness Rzjis and arithmetic average roughness Ra is a predetermined value, the variation is small, and excellent bending resistance can be obtained stably.

  In addition, in this way, the CCL process also serves as the recrystallization annealing process, and in the process until the rolled copper foil is bonded to the base material, the rolled copper foil can be handled in a work-hardened state after the cold rolling process. It is possible to prevent deformation such as elongation, wrinkling, and bending when the rolled copper foil is bonded to the base material.

  Each crystal plane in the sub-direction hardly changes before and after the recrystallization annealing process. Therefore, in order to obtain bending resistance and bending resistance, the sub-orientation should be controlled so that the above relational expression and conditions are satisfied for the rolled copper foil after the final cold rolling process and before the recrystallization annealing process. Good.

(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.

<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 mainly used as an additive for adjusting the heat resistance of the rolled copper foil, but the additive is not limited to those listed in Ag and the above-described representative examples. . 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 bending resistance and bending resistance. it can. The thickness of the rolled copper foil may also be ultra-thin of 10 μm or less, or over 20 μm, depending on various uses including FPC.

  Further, in the above-described embodiment, the total degree of work in the final cold rolling step S40 is set to 90% or more and the like, and excellent bending resistance is obtained. The obtained technique can be used independently of this. That is, when the bending resistance is particularly important and it is sufficient that a certain degree of bending resistance is obtained, the total degree of work in the final cold rolling step is, for example, 85%, 75%, 65%, etc. Thus, it may be less than 90%.

  In the above-described embodiment, in detecting the {013} plane and the {023} plane, among the X-ray pole-figure method, the measurement is performed by the reflection method, but the measurement is performed by the transmission method. It is good. In addition to the X-ray Pole-Figure method, an Inverse Pole-Figure (reverse pole figure) method and other methods may be used.

  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) Rolled copper foil using oxygen-free copper First, rolled copper foils according to Examples 1 to 4 and Comparative Examples 1 to 7 using oxygen-free copper were produced as follows, and various evaluations were performed on each. .

(Production of rolled copper foil)
The rolled copper foil which concerns on Examples 1-4 and Comparative Examples 1-7 was manufactured by the same procedure and method as the above-mentioned embodiment using the oxygen-free copper which added Ag which makes a target density | concentration 200 ppm. However, about Comparative Examples 1-7, the process etc. which remove | deviate a structure mainly in the last cold rolling process, such as the workability per pass mentioned later, the position of a neutral point, and the surface roughness of a rolling roll, were included.

  Specifically, 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 3 below shows the analytical values of the Ag concentration in the ingot, which were examined by high frequency inductively coupled plasma (ICP) emission spectroscopy.

  As shown in Table 3, with respect to the target concentration of 200 ppm, the analytical values are 183 ppm to 218 ppm, both of which are suppressed to variations within about 200 ppm ± 20 ppm (10%). Ag is originally contained in oxygen-free copper, which is the main raw material, as an inevitable impurity in the range of several ppm to several tens of ppm, and due to various causes such as variations in casting an ingot, the target concentration can be reduced. Variation within ± 10% 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 embodiment, the cold rolling step and holding at a temperature of 750 ° C. to 850 ° C. for about 2 minutes. The intermediate annealing step was repeatedly performed to produce a copper strip (fabric) having a thickness of 0.4 mm (400 μm). Subsequently, an annealed fabric was obtained in a fabric annealing process that was held at a temperature of about 750 ° C. for about 1 minute.

  Here, the temperature conditions of each annealing process were matched with the heat resistance of the oxygen-free copper material containing 183 ppm to 218 ppm of Ag. In addition, the reason why the different temperature conditions were used in each annealing process for copper materials with the same composition is that the heat resistance changes depending on the thickness of the copper material, and when the copper material is thin, the temperature should be lowered. Can do.

  Finally, the final cold rolling process was performed by the same procedure and method as in the above embodiment. The conditions in the final cold rolling process are shown in Table 4 below.

  As shown in Table 4, according to the progressive reduction of the plate thickness from the upper stage to the lower stage, in each of the examples and comparative examples, the conditions were changed as shown in the right column of each, and the final cold rolling was performed. . That is, the degree of processing per pass and the position of the neutral point of the cold rolling process with a thickness of 400 μm or less were changed. The position (mm) of the neutral point shown in each right column is indicated by the length from the outlet side end of the contact surface between the rolling roll and the annealed material as the workpiece to the neutral point.

  In each example and comparative example, conditions are set within the range in the right column so that each example falls within a predetermined configuration range, and each comparative example has a predetermined configuration. Processing was performed so that However, the conditions in Table 4 used this time are merely examples, and how much thickness is used to switch the conditions, and how to set the numerical values of each condition depends on the desired rolled copper foil crystal. It can select suitably according to a structure etc. As shown in the conditions of the comparative example, generally, when the thickness is reduced slowly, there is a tendency to deviate from this configuration.

  Moreover, the rolling roll with small surface roughness whose arithmetic mean roughness Ra is 0.075 micrometer or less is used for Examples 1-4, and the rolling roll with large surface roughness whose arithmetic mean roughness Ra is 0.080 micrometer or more is compared. Used in Examples 1-7.

  Moreover, in order to obtain the outstanding bending resistance, conditions were set so that the total degree of work in the final cold rolling process was 94% or more in all of Examples 1 to 4 and Comparative Examples 1 to 7. Specifically, in all of Examples 1 to 4 and Comparative Examples 1 to 7, the total degree of processing was set to 97%. By the above, the rolled copper foil which concerns on Examples 1-4 and Comparative Examples 1-7 whose thickness is 12 micrometers was manufactured.

  Next, the following evaluation was performed about each rolled copper foil manufactured as mentioned above.

(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 4 and Comparative Examples 1 to 7. Details of the measurement method will be described below with reference to FIG. FIG. 2 is a diagram showing an outline of a method for measuring X-ray diffraction in Examples and Comparative Examples of the present invention.

As shown in FIG. 2, the rolled copper foil sample pieces 50 according to Examples 1 to 4 and Comparative Examples 1 to 7 can be rotated around the three scanning axes of the θ axis, the ψ axis, and the φ axis as described above. To place. These three scanning axes are generally called a sample axis, a tilt axis, and an in-plane rotation axis, respectively. For the measurement of X-ray diffraction in the present embodiment, X-rays (Cu Kα rays) generated from a copper (Cu) tube are used.

  In the X-ray diffraction measurement using the 2θ / θ method, the sample piece 50 and a detector (not shown) are scanned (rotated around the θ axis) with respect to the incident X-ray. At this time, the scanning angle of the sample piece 50 is an angle θ, and the scanning angle of the detector is an angle 2θ. Thereby, as described above, incident X-rays are incident at an angle θ, and diffracted X-rays diffracted at an angle 2θ are detected.

  In this example and a comparative example, the measurement which concerns on the conditions shown in the following Table 5 was performed using the Rigaku Co., Ltd. X-ray-diffraction apparatus (model | form: Ultimate IV). As a representative, FIGS. 3A and 3B show the X-ray diffraction charts of Examples 1 and 2, and FIG. 3C shows the X-ray diffraction chart of Comparative Example 3, respectively.

Next, the total value of 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 is 100. In other words, the diffraction peak intensity ratio of each crystal plane was determined. Moreover, the value (I _{022} + I _{002} ) concerning Formula (1) described above was obtained. In Table 6 below, for the rolled copper foils according to Examples 1 to 4 and Comparative Examples 1 to 7, the diffraction peak intensity ratios I _{022} , I _{002} , I _{{ 113}} , I _{111} , I _{133} , and the value of Formula (1) are shown.

  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. Further, the surface roughness of the rolling roll is changed between the example and the comparative example. Thereby, the ratio of the stress component of the compression component added to a workpiece and a tension component changes at the time of cold rolling. As a result, the ratio of each crystal plane is changed, and the diffraction peak intensity ratio of each crystal plane shown in Table 6 and the value related to Equation (1) are also changed.

  Moreover, as shown in Table 6, in the combinations of the conditions of Examples 1 to 4, all the values of the expression (1) were within the predetermined range.

  On the other hand, in the combinations of the conditions of Comparative Examples 1 to 7, in some rolled copper foils, the value of the formula (1) was outside the above predetermined range. In Table 6, values outside the above-mentioned predetermined range are shown in bold with underline.

(Measurement by X-ray Pole-Figure method)
Next, the measurement by the X-ray Pole-Figure method was performed with respect to the rolled copper foil which concerns on Examples 1-4 and Comparative Examples 1-7. Such measurement methods include a reflection method in which a tilt angle ψ described later is in a range of 15 ° to 90 ° and a transmission method in which a tilt angle ψ is in a range of 0 ° to 15 °. In this example, the reflection method was used as in the above embodiment. Details of the measurement method will be described below with reference to FIG.

  As shown in FIG. 2, in the measurement using the X-ray Pole-Figure method, the sample piece 50 of each rolled copper foil is arranged similarly to the X-ray diffraction measurement using the 2θ / θ method described above.

  In the X-ray Pole-Figure method, measurement is performed using a tilt angle ψ defined as follows. That is, the tilt angle ψ in the direction perpendicular to the sample piece 50 (φ-axis direction) is defined as 90 °. Further, an angle formed by the {h′k′l ′} plane, which is a crystal plane geometrically corresponding to the {hkl} plane, which is the crystal plane of interest, is defined as ψ ′. At this time, the tilt angle ψ = 90−ψ ′ is defined.

  Under such a definition, the sample piece 50 is scanned by the ψ axis (rotated around the ψ axis), and the tilt angle ψ is changed within a range of 15 ° to 90 °. That is, the sample piece 50 is tilted at the tilt angle ψ within the above range. In this way, while changing the tilt angle ψ, diffracted X-rays are detected at a plurality of tilt angles ψ as in the 2θ / θ method. That is, when the tilt angle ψ is 90 °, the same measurement as the 2θ / θ method is performed in principle.

  In the measurement at each tilt angle ψ, the scanning angle of the detector is fixed at an angle 2θ, and the sample piece 50 is scanned on the φ axis with respect to the 2θ value on the {h′k′l ′} plane (around the φ axis). And the in-plane rotation angle φ is changed within a range of 0 ° to 360 °. That is, the sample piece 50 is rotated at an in-plane rotation angle φ within the above range. For the diffraction peaks of the {h′k′l ′} plane measured in this way, the average intensity of the diffraction peaks in the range where the in-plane rotation angle φ is 0 ° or more and 360 ° or less is obtained for each tilt angle ψ. .

  At this time, the {h′k′l ′} plane detected at a predetermined tilt angle ψ geometrically corresponds to the {hkl} plane parallel to the rolled surface of the rolled copper foil. The {hkl} planes to be noted in this embodiment are the {013} plane and the {023} plane. The {111} plane detected at a tilt angle ψ of 47 ° has a geometrical correspondence with the {013} plane parallel to the rolling plane of the rolled copper foil. Further, the {111} plane detected at a tilt angle ψ of 53 ° has a geometrical correspondence with the {023} plane parallel to the rolling plane of the rolled copper foil.

  Therefore, as described above, from the graph of the average intensity of the diffraction peak of the {111} plane obtained using the X-ray Pole-Figure method, it is determined whether or not the rolled copper foil of this example has a predetermined crystal structure. Can be determined.

  In this example and a comparative example, the above-described measurement was performed under the conditions shown in Table 7 below using an X-ray diffractometer (model: Ultimate IV) manufactured by Rigaku Corporation. 4 to 7 show graphs created by plotting the average intensity of the diffraction peaks on the {111} plane according to Examples 1 to 4. FIG. Moreover, the graph created by plotting the average intensity | strength of the diffraction peak of the {111} surface which concerns on FIGS.

The horizontal axis of the graphs of FIGS. 4 to 14 is the tilt angle ψ (°), and the vertical axis is the diffraction peak intensity (arbitrary unit). In the graph, the average intensities obtained by the measurement using the X-ray Pole-Figure method described above are plotted. Further, the graph shows the maximum value [B] of the average intensity of diffraction peaks on the {111} plane within the range of the graph and a value of a quarter thereof. In addition, the graph shows a straight line connecting the average intensities of diffraction peaks on the {111} plane when the tilt angle ψ is 47 ° and 53 °, respectively, and its vertical axis intercept [A].

  As shown in FIGS. 4 to 14, in the results of Examples 1 to 4, in all cases, the vertical axis intercept [A] is equal to or greater than one-fourth of the maximum value [B] of the graph, and the above equation (2) is satisfied. I met. Moreover, also in Comparative Examples 1 and 2, the graph which satisfy | fills Formula (2) was obtained. On the other hand, in the results of Comparative Examples 3 to 7, in all cases, the vertical axis intercept was less than a quarter of the maximum value of the graph and did not satisfy the above formula (2).

(Surface roughness measurement)
Then, in order to see the surface roughness of the rolled copper foil which concerns on Examples 1-4 and Comparative Examples 1-7, 10-point average roughness Rzjis and arithmetic average roughness Ra were measured. For the measurement, a surface roughness measuring machine (model: SE500) manufactured by Kosaka Laboratory Ltd. was used. The measurement conditions were a stylus diameter of 2 μm, a measurement speed of 0.2 mm / sec, a measurement length of 4 mm, a sampling reference length of 0.8 mm, and a load of 0.75 mN or less. The measurement results are shown in Table 8 below.

  As described above, in the present example and the comparative example, rolling rolls having different surface roughness, that is, arithmetic average roughness Ra, are used in the final cold rolling step. Therefore, as shown in Table 8, in the combination of the conditions of Examples 1 to 4, the surface of the rolled copper foil is relatively flattened, and both the ten-point average roughness Rzjis and the arithmetic average roughness Ra are described above. It was within the predetermined range.

  On the other hand, in the comparative example, although only the comparative example 7 had both surface roughness within the predetermined value, in the rolled copper foil of the other comparative examples 1-6, either one or both surface roughness The value was outside the above-mentioned predetermined range. In Table 8, values outside the above-mentioned predetermined range are shown in bold with underline.

(Evaluation of bending resistance)
Next, in order to examine the bending resistance of each rolled copper foil, a bending fatigue life test was performed in which the number of repeated bendings (number of bendings) until each rolled copper foil broke. Such a test was performed using an FPC high-speed bending tester (model: SEK-31B2S) manufactured by Shin-Etsu Engineering Co., Ltd. in accordance with the IPC (American Printed Circuit Industry Association) standard. FIG. 15 shows a schematic diagram of a general sliding bending test apparatus 10 including an FPC high-speed bending tester manufactured by Shin-Etsu Engineering Co., Ltd.

First, the rolled copper foils according to Examples 1 to 4 and Comparative Examples 1 to 7 were cut into a width of 12.5 mm and a length of 220 mm, and a sample piece 50 having a thickness of 12 μm was copied according to the above-described recrystallization annealing step. Recrystallization annealing was performed at 300 ° C. for 60 minutes. Such a condition is C of the flexible printed wiring board.
In the CL process, an example of the amount of heat that the rolled copper foil actually receives during close contact with the substrate is illustrated.

  Next, as shown in FIG. 15, a rolled copper foil sample piece 50 was fixed to the sample fixing plate 11 of the sliding bending test apparatus 10 with screws 12. Subsequently, the specimen piece 50 was attached in contact with the vibration transmission section 13, and the vibration transmission section 13 was vibrated in the vertical direction by the oscillation driver 14 to transmit vibration to the specimen piece 50, and a bending fatigue life test was performed. . As the measurement conditions for the bending fatigue life, the bending radius 10r was 1.5 mm, the stroke 10 s was 10 mm, and the amplitude number was 25 Hz. Under such conditions, five sample pieces 50 cut from each rolled copper foil were measured, and the average values of the number of bendings until breakage occurred were compared. The results are shown in Table 9 below.

  As shown in Table 9, in each of Examples 1 to 4 and Comparative Examples 1, 2, 4, and 6, all satisfy the above-described formula (1), and thus high bending resistance with a number of bendings of 2 million times or more is achieved. Obtained. On the other hand, in Comparative Examples 3, 5, and 7 that do not satisfy the above-described formula (1), the number of bendings was significantly less than 2 million.

  Here, it should be noted that even Comparative Examples 3, 5, and 7 originally have a relatively high level of bending resistance. This is because, for example, the total work degree that has been obtained in the above-mentioned Patent Document 3 is 94% or more, specifically, the final cold rolling process has been performed with a total work degree of 97%. In Examples 1 to 4, it was possible to further improve the bending resistance by satisfying the above formula (1).

(Evaluation of bending resistance)
Subsequently, the bending resistance of each rolled copper foil was investigated. In general test standards for bending resistance, standardization for bending at 180 °, which is required for FPC applications, for example, has not been made. Therefore, a bending test was performed to measure the number of bendings until cracking occurred in each rolled copper foil by the method shown in FIG.

That is, first, a sample piece 50 obtained by cutting the rolled copper foils according to Examples 1 to 4 and Comparative Examples 1 to 7 to a width of 15 mm and a length of 100 mm with respect to the rolling direction was subjected to recrystallization annealing at 300 ° C. for 60 minutes. gave. Next, as shown in FIG. 16, the sample piece 50 was bent 180 ° so as to sandwich the spacer 20 having a thickness of 0.15 mm, and in this state, the bent portion was observed with a metal microscope to confirm the presence or absence of cracks. If there was no crack, the rolled copper foil was returned from the folded state to the original stretched state. With this as one cycle, for each of five sample pieces 50 cut out from each rolled copper foil, the cycle was repeated until cracks occurred while observing the bent portion every cycle, and the number of bendings was measured. The results are shown in Table 10 below.

  As shown in Table 10, in any of Examples 1 to 4 satisfying both the above-described formulas (2), (3), and (4), the number of foldings is 100 times or more, and excellent bending resistance is obtained. It was. Moreover, about these rolled copper foil, it was confirmed that there was little variation in the measurement result of the above-mentioned five sample pieces 50, and the stable bending resistance was obtained.

  On the other hand, in any of the comparative examples except Comparative Examples 1 and 2, the formula (2) was not satisfied, and the number of bendings was less than 100, so that sufficient bending resistance was not obtained. The same applies to Comparative Example 7 that satisfies both the surface roughness values. That is, the improvement of the bending resistance by controlling the surface roughness is premised on satisfying Expression (2). However, in Comparative Examples 1 and 2 satisfying only the formula (2), the number of bendings was barely 100 times or more, and although slightly inferior to the Examples, a slight improvement was recognized as compared with the other Comparative Examples.

  Table 11 below summarizes the above results for each rolled copper foil. In the table, those satisfying the predetermined conditions were marked with ◯, and those outside the conditions were marked with x. Comparative examples 1 and 2, which had better folding resistance results than the other comparative examples and worse than the examples, were evaluated as Δ.

  As described above, when the value of the above formula (1) is within the predetermined value, that is, by controlling from the inner viewpoint regarding the material of the rolled copper foil, the crystal orientation including the sub-orientation, etc. Excellent bending resistance is imparted to the copper foil. Further, the above-mentioned formula (2) and the surface roughness value relating to the mechanical or appearance shape are within a predetermined value, that is, control from both the internal and external viewpoints of the rolled copper foil. Thus, excellent bending resistance is stably imparted to the rolled copper foil.

  Since the rolled copper foil which concerns on Examples 1-4 satisfy | fills all the above-mentioned values, both the bending resistance and the bending resistance showed a high value, and the variation was small and stable bending resistance was obtained.

  On the other hand, Comparative Examples 1 and 2 satisfy both the above-mentioned formulas (1) and (2), and are controlled from an internal viewpoint. However, only one of the values of the surface roughness is satisfied, and control from an external viewpoint is not made. Therefore, although excellent bending resistance was obtained, the bending resistance was inferior to that of the examples.

  Further, Comparative Examples 3 to 7 do not satisfy either or both of the above formulas (1) and (2), and except for Comparative Example 7, do not satisfy either or both of the surface roughness. Therefore, both the control from the inner viewpoint and the control from the outer viewpoint are insufficient. For this reason, all of the results were inferior in bending resistance except for Comparative Examples 4 and 6, which satisfied the formula (1) and barely had only good bending resistance. Moreover, in any of Comparative Examples 3 to 7, the bending resistance was inferior to that of Comparative Examples 1 and 2.

(2) Rolled copper foil using tough pitch copper Next, a tough pitch copper to which Ag with a target concentration of 200 ppm was added was used in the same procedure and method as in the above-described embodiment, and the thickness was 12 μm. 6 and Comparative Examples 8 to 10 were produced. However, about Comparative Examples 8-10, the process etc. which remove | deviate from a structure, such as the conditions of the above-mentioned Table 4, the surface roughness of a rolling roll, etc. were included.

The Ag concentrations in the ingots of Examples 5 and 6 and Comparative Examples 8 to 10 are analytical values obtained by IPC emission spectroscopy, and are 201 ppm, 194 ppm, 202 ppm, and 190 p, respectively.
pm, and 198 ppm. All are variations within about ± 10% of the target concentration, and are common in the field of metal materials. In addition, the conditions different from the above-mentioned conditions were used in the intermediate annealing process and the dough annealing process in accordance with the heat resistance of the tough pitch copper material containing Ag of such concentration. Specifically, the intermediate annealing step was held at a temperature of 650 ° C. to 750 ° C. for about 2 minutes, and the dough annealing step was held at a temperature of about 700 ° C. for about 1 minute. Moreover, also about these Examples and the comparative examples, the conditions of the above-mentioned Table 4 were applied to the final cold rolling process.

  For the rolled copper foils according to Examples 5 and 6 and Comparative Examples 8 to 10 manufactured as described above, X-ray diffraction measurement and X-ray Pole-Figure by the 2θ / θ method are performed in the same manner and procedure as in the above-described Examples. Measurement using the method was performed to obtain the above-mentioned formulas (1) and (2), and the surface roughness was measured in the same manner as described above.

  Moreover, after performing recrystallization annealing similar to the above with respect to the rolled copper foil which concerns on Examples 5 and 6 and Comparative Examples 8-10, a bending fatigue life test and bending are performed by the same method and procedure as the above-mentioned Example. A test was conducted.

  Table 12 below shows the above results. In Table 12, values outside the predetermined range of any of the above formulas (1) to (4) are shown in bold underlined.

  As shown in Table 12, for the rolled copper foils according to Examples 5 and 6, both the expressions (1) and (2) were satisfied, and the values of the expressions (3) and (4) were also satisfied. For this reason, both the bending resistance and the bending resistance were good results. On the other hand, about the rolled copper foil which concerns on the comparative example 8, only Formula (2) was out of the predetermined range and it resulted in that bending resistance was bad. Moreover, about the rolled copper foil which concerns on the comparative example 9, although Formula (1) and (2) was in the predetermined range, both surface roughness remove | deviated from the predetermined value, and also bend-proof property rather than an Example. Had bad results. Moreover, about the rolled copper foil which concerns on the comparative example 10, it deviated from the predetermined value on all the conditions, and it became a result with bad bending resistance and bending resistance.

  From the above, it can be seen that, if each condition is within a predetermined range, it is possible to obtain a good bending resistance and to further improve the bending resistance with respect to a rolled copper foil mainly made of tough pitch copper. It was.

(3) Rolled copper foil using different additive materials 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 Examples 7 and 8 and Comparative Examples 11-13 whose thickness is 12 micrometers was manufactured with the same procedure and method. However, about the comparative examples 11-13, the process etc. which remove | deviate a structure, such as the conditions of the above-mentioned Table 4 and the surface roughness of a rolling roll, were included.

  The Ag concentrations in the ingots of Examples 7 and 8 and Comparative Examples 11 to 13 were 118 ppm, 121 ppm, 117 ppm, 120 ppm and 118 ppm, respectively, as analytical values obtained by IPC emission spectroscopic analysis. Ti concentrations were 38 ppm, 42 ppm, 40 ppm, 40 ppm, and 37 ppm, respectively. All are variations within about ± 10% of the target concentration, and are common in the field of metal materials.

  Further, in accordance with the heat resistance of the oxygen-free copper material containing such concentrations of Ag and Ti, conditions different from the above-described conditions were used in the intermediate annealing process and the dough annealing process. Specifically, the intermediate annealing step was held at a temperature of 650 ° C. to 750 ° C. for about 2 minutes, and the dough annealing step was held at a temperature of about 700 ° C. for about 1 minute. Moreover, also about these Examples and the comparative examples, the conditions of the above-mentioned Table 4 were applied to the final cold rolling process.

  For the rolled copper foils according to Examples 7 and 8 and Comparative Examples 11 to 13 manufactured as described above, X-ray diffraction measurement and X-ray Pole-Figure by the 2θ / θ method are performed in the same manner and procedure as in the above-described Examples. Measurement using the method was performed to obtain the above-mentioned formulas (1) and (2), and the surface roughness was measured in the same manner as described above.

  Moreover, after performing recrystallization annealing similar to the above with respect to the rolled copper foil which concerns on Examples 7 and 8 and Comparative Examples 11-13, a bending fatigue life test and bending by the method and procedure similar to the above-mentioned Example A test was conducted.

  Table 13 below shows the above results. In Table 13, values outside the predetermined range of any of the above formulas (1) to (4) are shown in bold underlined.

  As shown in Table 13, for the rolled copper foils according to Examples 7 and 8, the relationship between the diffraction peak intensities of the crystal planes satisfies both the expressions (1) and (2), and the expressions (3) and ( The value of 4) was also satisfied. For this reason, both the bending resistance and the bending resistance were good results. On the other hand, about the rolled copper foil which concerns on the comparative example 11, only Formula (1) removed from the predetermined range and it resulted in that bending resistance was bad. Moreover, about the rolled copper foil which concerns on the comparative example 12, only Formula (2) removed from the predetermined range, and it became a result that bending resistance was bad. Further, for the rolled copper foil according to Comparative Example 13, only the arithmetic average roughness Ra out of the predetermined value out of the surface roughness was inferior in stability, but the bending resistance was better than that in Comparative Example 12. It was.

  From the above, it was found that if each condition is within a predetermined range, good bending resistance and bending resistance can be obtained also for the rolled copper foil added with different additives such as Ag and Ti. .

<Discussion by the present inventors>
The inventors' consideration on the control of the sub-oriented crystal plane and the control of the surface roughness in the manufacturing process of the rolled copper foil described above will be described below.

(1) About crystal rotation As described above, during the rolling process such as the final cold rolling process, the copper material is subjected to compressive stress and tensile stress 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. 17 is a reverse pole figure of a pure copper type metal quoted from the following technical document (A), (a) is a reverse 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.

  (B) Editor Shinichi Nagashima, “Aggregate Organization”, Maruzen Co., Ltd., January 20, 1984, p. 96, Figures 2.52 (a) and (c)

  As shown in FIG. 17, the copper crystal in the copper material rotates toward the {111} plane only by deformation due to tensile stress, and rotates toward the {011} plane only by deformation due to compressive stress. 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 are mixed while maintaining the relationship of compression component> tensile component, the crystal plane of the main orientation finally becomes the {011} plane, As a result of crystal rotation by mixing the compression component and the tensile component, the crystal planes in the sub-orientation are considered to be {001}, {113}, {111}, and {133} planes.

  In addition, there are {013} planes, {023} planes, and the like as crystal planes that pass through crystal rotation due to compressive stress. Although the crystal orientation of the inverse pole figure shown in FIG. 18 is general, the {013} plane, the {023} plane, and the crystal plane region where the orientation difference between these crystal planes is relatively small are drawn. added. As shown in FIG. 18, in the crystal rotation due to the compressive stress, the crystal rotates to the {011} plane ({022} plane) via the {013} plane, the {023} plane, and the like.

In the rolling process, as described above, if both the compressive stress and the tensile stress weaker than the compressive stress are not applied to the rolled copper material, the copper material cannot be rolled while maintaining the shape of the copper material. That is, only compressive stress results in a shape that expands and spreads radially, as in mere pressing. Under the premise that compressive stress> tensile stress, the crystal that has rotated toward the {111} plane becomes the sub-azimuth due to the remaining orientation that did not reach the {022} plane and the influence of tensile stress. As described above, the {111} plane that lowers the bending resistance is a sub-orientation formed by tensile stress, and the {013} plane and {023} plane that improve the bending resistance are sub-directions formed by compressive stress. It is an azimuth.

  Therefore, in order to suppress the occupancy ratio of the {111} plane on the rolled surface of the rolled copper foil as much as possible and increase the occupancy ratio of the {013} plane and {023} plane as much as possible, while appropriately adjusting the balance between the compressive stress and the tensile stress. It is important to roll.

(2) Characteristic control in the final cold rolling process The compression component and the tensile component change the rolling conditions per pass at the time of rolling, for example, as in the final cold rolling process S40 according to the above-described embodiment. Can be controlled. That is, as tried in the above-described embodiments and examples, attention can be paid to a change in the processing degree per pass, for example.

  Moreover, in the above-mentioned embodiment and Example, the position control of the neutral point is 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.

  Control factors such as the above-described degree of processing and the position of the neutral point are related to the configuration of the rolling mill and largely depend on the specifications of the rolling mill. Specifically, depending on the difference in the number of rolling rolls, the total number of rolling rolls, the combined arrangement of the rolling rolls, the diameter and material of each rolling roll, the configuration of the rolling rolls such as the surface condition (surface roughness), etc. There is a difference in the way the compressive stress is applied and the friction coefficient. 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. Further, even in the same rolling mill, the absolute value of each control factor is different if the surface state of the rolling roll and the material of the rolling roll are different. Therefore, even if it is the same rolling mill, it can adjust suitably according to each state.

  In the above-described embodiments and examples, control based on the surface roughness of the rolling roll is also performed. For example, if the degree of processing per pass is constant and the surface roughness of the rolling roll is changed, the friction coefficient applied to the rolled copper material changes, the position of the neutral point changes, and the rolling load also changes. As a result, the balance between the compressive stress and the tensile stress in the rolling process changes, and the rotation direction and the rotation path of the copper crystal change.

(3) Property control by surface roughness of rolling roll As described above, the present inventors define the surface roughness of the rolled copper foil by a ten-point average roughness Rzjis and an arithmetic average roughness Ra, which are predetermined. It has been found that the bending resistance of the rolled copper foil can be improved by keeping it below the value.

Thus, the surface roughness that stably imparts excellent bending resistance to the rolled copper foil can be controlled by, for example, the following factors. That is, the viscosity η of the rolling oil, the rotation speed U ₀ of the rolling roll, the speed U ₁ of the copper material during rolling, the biting angle α, the average rolling pressure p, the surface roughness of the rolling roll (arithmetic average roughness) Ra) and the like. Among these factors, factors other than the arithmetic average roughness Ra of the rolling rolls are as oil film equivalent td corresponding to the thickness of the oil film, as in the following formula (B) with reference to the following technical literature (b). Can be combined into one.

td = {η (U ₀ + U ₁ )} / αp (B)

  (B) Akira Shodoshima, “About oil film thickness during rolling and surface roughness of rolls and materials”, Transactions of the Japan Society of Mechanical Engineers (Part 3), Vol. 44, 377, January 1978, p332-339

If the oil film equivalent td defined by factors other than the arithmetic average roughness Ra of the rolling roll can be kept constant, the influence of these factors can be reduced, mainly by the arithmetic average roughness Ra of the rolling roll, The surface roughness of the rolled copper foil can be controlled in various ways.

Here, the rotation speed U _{0 of} the rolling roll according to the above formula (B), the speed U ₁ of the copper material during rolling, and the average rolling pressure p control the degree of processing and neutral point per pass under rolling conditions. It is also a controlling factor. In order to control the degree of processing and the neutral point per pass, when these control factors are changed, for example, the following method is used to keep the oil film equivalent td constant. For example, if it is controlled to a constant viscosity of the rolling oil η in the range of ^{3 × 10 -3 N / m 2} · s~5 × 10 -3 N / m 2 · s, the angular biting α is constant. Therefore, the oil film equivalent td can be controlled to be constant.

  In the final cold rolling step S40 according to the above-described embodiment, for example, the oil film equivalent td is appropriately adjusted, and the surface roughness of the rolling roll is set to a predetermined value, so that the rolled copper having the predetermined surface roughness is used. A foil can be produced.

  In the above-described embodiments and examples, the surface roughness of the rolling roll is defined by the arithmetic average roughness Ra for the following reason.

  That is, the rolling roll is an important tool used in the final cold rolling step S40 and related to the deformation processing of the copper material. Therefore, it is important to capture the state of the entire rolling roll as little as possible. Therefore, it was decided to grasp the overall surface roughness of the rolling roll by using the arithmetic average roughness Ra captured by a surface or a line instead of capturing the unevenness difference by points.

  In addition, you may control the surface roughness of the rolled copper foil which improves bending resistance using another control factor.

(4) Other control factors In the above-described embodiments and examples, the rotation direction and the rotation path of the copper crystal were controlled by the rolling conditions including the surface roughness of the rolling roll in the final cold rolling process. Similar control is possible in other processes.

  For example, by making the rolling conditions in the final cold rolling process constant and changing the manufacturing process conditions until just before the final cold rolling process, the final cold rolling process is also affected, and the rotation in the final cold rolling process It is considered possible to indirectly change the direction and the rotation path. However, if the rolling conditions in the final cold rolling process are changed as in the above-described embodiments and examples, the rotation direction and the rotation path can be directly controlled, and the controllability can be further enhanced. .

  Thus, the state of the crystal orientation of the rolled copper foil after the final cold rolling step is not limited by a specific manufacturing method. This is because the crystal orientation state of the rolled copper foil can be controlled by various methods, and there are various methods.

DESCRIPTION OF SYMBOLS 10 Sliding bending test apparatus 11 Sample fixing plate 12 Screw 13 Vibration transmission part 14 Oscillation drive body 20 Spacer 50 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,
Made of pure copper or dilute copper alloy,
In the final cold rolling step, the balance between the compressive stress that rotates the crystal toward the {011} plane and the tensile stress that rotates the crystal toward the {111} plane is the {013} plane and the {023} plane It is rolled while adjusting so as to increase the occupation rate of
The plurality of crystal planes include {022} plane, {002} plane, {113} plane, {111} plane, and {133} plane,
The diffraction peak intensity ratios of the crystal planes obtained by X-ray diffraction measurement using the 2θ / θ method with respect to the main surface and converted so that the total value becomes 100 are I _{022} and I _[002} , respectively _. , I _{113} , I _{111} , and I _{133} ,
I _{022} + I _{002} ≧ 75.0,
Using X-ray Pole-Figure method, for each of a plurality of tilt angles within a range of 15 ° to 90 °, the in-plane rotation angle of the main surface is changed within a range of 0 ° to 360 °. The average intensity of the diffraction peaks of the {111} plane
When creating a graph plotting the average intensity of diffraction peaks of the {111} plane with the tilt angle as the horizontal axis and the diffraction peak intensity as the vertical axis,
A vertical axis intercept of a straight line connecting the average intensity of the diffraction peak of the {111} plane at the tilt angle of 47 ° and the average intensity of the diffraction peak of the {111} plane at the tilt angle of 53 ° is [A When the maximum value of the average intensity of the diffraction peaks of the {111} plane in the range where the tilt angle is 15 ° or more and 90 ° or less is [B],
[A] / [B] ≧ 1/4,
The surface roughness of the main surface is
Ten-point average roughness Rzjis ≦ 1.2 μm,
An arithmetic average roughness Ra ≦ 0.3 μm. The rolled copper foil according to claim 1, comprising oxygen-free copper or tough pitch copper as a main component. The rolled copper foil according to claim 1 or 2, wherein at least one of silver, boron, titanium, and tin is added. Thickness is 20 micrometers or less, The rolled copper foil in any one of Claims 1-3 characterized by the above-mentioned. 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.