JP5246526B1 - Rolled copper foil - Google Patents

Abstract

An object of the present invention is to provide excellent bending resistance as well as high bending characteristics.
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 ratios of the crystal planes obtained from the X-ray diffraction measurement using the method and converted so that the total value becomes 100 are I _{022} , I _{002} , I _{113} , I _{{ 111}} and I _{133} , I _{113} ≦ 6.0, I _{111} ≦ 6.0, and I _{133} ≦ 6.0.
[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. Therefore, folding parts of folding cellular phones, movable parts such as digital cameras and printer heads, hard disk drives (HDD: Hard Disk Drive), digital versatile disks (DVDs), compact disks (CDs: Compact Disks), etc. In many cases, FPC is used for wiring of the movable part of the disk-related equipment. Therefore, the rolled copper foil used as FPC and its wiring material has been required to have excellent bending characteristics that can withstand repeated bending.

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

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

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

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

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

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

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

  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, and there is an increasing demand for bending resistance that allows a small bending radius for a rolled copper foil. .

  In this way, in order to meet the demands for high bending characteristics that can withstand repeated bending and bending resistance that can withstand a small bending radius, which differ depending on the application, etc., in the past, different characteristics have been used for each application. The rolled copper foil was manufactured separately. 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 have excellent bending resistance as well as high bending properties after the recrystallization annealing step. In this way, if a rolled copper foil that has both characteristics can be realized, it can be applied to both applications that emphasize high bending characteristics and applications that emphasize bending resistance, thereby significantly improving production efficiency. be able to.

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 _{113} ≦ 6.0,
I _{111} ≦ 6.0, and
A rolled copper foil with I _{133} ≦ 6.0 is provided.

According to a second aspect of the invention,
Standard diffraction peaks of each crystal plane described in the JCPDS card or ICDD card for powdered copper having a {022} plane, a {002} plane, a {113} plane, a {111} plane, and a {133} plane The diffraction peak intensity ratios of the crystal planes calculated from the relative intensities and converted so that the total value becomes 100 are I _{0 {022}} , I _{0 {002}} , I _{0 {113}} , I _{0 {111, respectively. } And} I _{0 {133}} ,
I _{113} / I0 _{113} ≦ 0.70,
I _{111} / I0 _{111} ≦ 0.12, and
The rolled copper foil as described in the 1st aspect which is I _{133} / I0 _{133} <= 1.3 is provided.

According to a third aspect of the invention,
The rolled copper foil as described in the 1st or 2nd aspect which is I _{002} > = 7.5 is provided.

According to a fourth aspect of the invention,
Standard diffraction peaks of each crystal plane described in the JCPDS card or ICDD card for powdered copper having a {022} plane, a {002} plane, a {113} plane, a {111} plane, and a {133} plane The diffraction peak intensity ratios of the crystal planes calculated from the relative intensities and converted so that the total value becomes 100 are I _{0 {022}} , I _{0 {002}} , I _{0 {113}} , I _{0 {111, respectively. } And} I _{0 {133}} ,
The rolled copper foil in any one of the 1st-3rd aspect which is I _{002} / I0 _{002} > = 0.30 is provided.

According to a fifth aspect of the present invention,
The rolled copper foil in any one of the 1st-4th aspect which has an oxygen free copper prescribed | regulated to JIS C1020 or a tough pitch copper prescribed | regulated to JIS C1100 as a main component is provided.

According to a sixth aspect of the present invention,
The rolled copper foil in any one of the 1st-5th aspect to which at least any one of silver, boron, titanium, and tin is added is provided.

According to a seventh aspect of the present invention,
The rolled copper foil in any one of the 1st-6th aspect by which the thickness is 20 micrometers or less by the said last cold rolling process whose total workability is 90% or more is provided.

According to an eighth aspect of the present invention,
The rolled copper foil in any one of the 1st-7th 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 a high bending property 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 measurement result of X-ray diffraction using 2θ / θ method, and (a) is an X-ray diffraction chart of a rolled copper foil according to an example of the present invention, and (b) X of a rolled copper foil according to a comparative example. It is a line diffraction chart. It is a schematic diagram of the sliding bending test apparatus which measures the bending characteristic of the rolled copper foil which concerns on the Example of this invention. It is a figure which shows the outline | summary of the test method of the 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. It is a reverse pole figure which shows the crystal orientation of the rolled copper foil after a final cold rolling process and before a recrystallization annealing process.

<Knowledge obtained by the present inventors>
As described above, in order to obtain a rolled copper foil having high bending characteristics required for FPC applications, it is better to develop the cube orientation of the rolled surface. The present inventors have also conducted various experiments in order to increase the occupation ratio of the cube orientation. And from the experimental results so far, when the {022} plane existing after the final cold rolling step is tempered to recrystallization by 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 and the present inventors, even if a large amount of cube texture is expressed, the {002} plane which is a cube texture in a rolled copper foil having a polycrystalline structure is present. It does not occupy 100%. For example, if this is the state after the final cold rolling step, the sub-orientation crystal planes such as {113} plane, {111} plane and {133} plane are controlled in addition to the {022} plane which is the main orientation. It is considered that a plurality of crystal grains having a plurality of crystal planes without affecting the various characteristics of the rolled copper foil. Therefore, the present inventors have focused on the sub-orientation crystal planes that have been made unnecessary so far, while maintaining high bending characteristics without reducing the occupancy of the main orientation, Have been investigating whether it is possible to add new performance.

  As a result of such earnest research, the present inventors added a new addition to the rolled copper foil by controlling the ratio of the sub-oriented crystal planes such as {113} plane, {111} plane, {133} plane, etc. It has been found that excellent bending resistance can be imparted as a value.

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

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

(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. That is, the rolled copper foil according to this embodiment has a total workability of 90% or more, more preferably 94% or more in the final cold rolling step so as to be used for flexible wiring material applications such as FPC. After that, as described above, for example, a recrystallization annealing process is performed also as a bonding process with an FPC base material, and excellent reflex characteristics are obtained by recrystallization. It is intended to.

  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 high bending properties can be obtained.

(Crystal structure of rolled surface)
The rolled copper foil has a plurality of crystal planes parallel to the rolled surface. Specifically, after the final cold rolling step and before the recrystallization annealing step, the plurality of crystal planes include {022} plane, {002} plane, {113} plane, {111} plane, and { 133} plane is included. The {022} plane is the main orientation in the rolling plane, and the other crystal planes are sub-azimuths. Thus, in the rolled surface, each crystal plane has a predetermined occupation ratio. The occupation ratio of each crystal plane can be obtained from X-ray diffraction measurement with respect to the rolled surface of the rolled copper foil.

  That is, the diffraction peak intensities of the five crystal planes measured by X-ray diffraction using the 2θ / θ method are converted into a ratio such that the total value becomes 100, and the diffraction peak intensity ratio of each crystal plane is obtained. 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, the diffraction peak intensity ratio of each crystal plane is set to I _{022} , I _{002} , I _{113} , I _{111} , and I _{133} , respectively, and the diffraction peak intensity of each crystal plane is set to I _{Let {{022}} , I ' _{002} , I' _{113} , I ' _{111} , and I' _{133} .

  In the rolled copper foil according to the present embodiment, the diffraction peak intensity ratio of each crystal plane has a relationship in which all of the following formulas (1) to (3) hold, for example.

I _{113} ≦ 6.0 (1)
I _{111} ≦ 6.0 (2)
I _{133} ≦ 6.0 (3)

  Further, the value of the diffraction peak intensity ratio of each crystal plane can be defined based on the standard diffraction peak intensity ratio of copper. Examples of the standard diffraction peak of copper include a diffraction peak of powdered copper having a {022} plane, a {002} plane, a {113} plane, a {111} plane, and a {133} plane. For example, the JCPDS (Joint Committee for Powder Diffraction Standards) card (card number: 40836) or the ICDD (International Center for Diffraction Data) card describes the relative intensity of such diffraction peaks.

  Convert the relative intensity of the standard diffraction peaks of the above five crystal planes into a ratio such that the total value is 100, and obtain the diffraction peak intensity ratio of each crystal plane for powdered copper, and use this as the reference value. Can do.

A conversion formula (B) for obtaining the diffraction peak intensity ratio of the {022} plane as a representative from the relative intensity of the diffraction peak of each crystal plane is shown below. Here, the diffraction peak intensity ratio of each crystal plane in powder copper is set to I _{0 {022}} , I _{0 {002}} , I _{0 {113}} , I _{0 {111}} , and I _{0 {133}} , respectively, The diffraction peak intensities of the surfaces are I ₀ ′ _{022} , I ₀ ′ _{002} , I ₀ ′ _{113} , I ₀ ′ _{111} , and I ₀ ′ _{133} , respectively.

  In the rolled copper foil according to the present embodiment, in addition to the above formulas (1) to (3), preferably, the following formula (4) using the diffraction peak intensity ratio of each crystal plane in the powdered copper as a reference value: The relations (6) to (6) are all satisfied.

I _{113} / I0 _{113} ≦ 0.70 (4)
I _{111} / I0 _{111} ≦ 0.12 (5)
I _{133} / I _{0 {133}} ≦ 1.3 (6)

  Moreover, in the rolled copper foil which concerns on this embodiment, Preferably the following formula | equation (7) is materialized.

I _{002} ≧ 7.5 (7)

The peak intensity ratio I _{002} of the {002} plane is also defined as follows, with the diffraction peak intensity ratio I _{0 {002}} of the {002} plane in powdered copper as a reference value. Can do.

I _{002} / I0 _{002} ≧ 0.30 (8)

(Action of crystal structure)
As described above, the rolled copper foil according to the present embodiment is configured to have excellent bending resistance that can withstand a small bending radius as well as high bending characteristics that can withstand repeated bending after the recrystallization annealing step.

  That is, 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 as it is after the recrystallization annealing process. Improve the bending properties of the rolled copper foil. The other {113} plane, {111} plane, and {133} plane are unnecessary crystal planes that do not contribute to bending characteristics. Therefore, for the crystal plane, when the above formulas (1) to (3) are satisfied, and preferably when the above formulas (4) to (6) are satisfied, the unnecessary crystal plane is reduced and the bending characteristics are improved. It will be advantageous.

  Further, the present inventors have a relationship in which all of the above formulas (1) to (3) are satisfied, and preferably in a relationship in which all the above formulas (4) to (6) are satisfied, It has been found that excellent bending resistance is exhibited after the recrystallization annealing process. That is, when all of the {113} plane, {111} plane, and {133} plane among the sub-azimuths are lower than a predetermined ratio, the bending resistance is improved.

  In addition, the inventors of the present invention found that the {002} plane existing in the rolled copper foil after the final cold rolling process and before the recrystallization annealing process is based on the recrystallization annealing process from the {022} plane to the {002} plane. I found that there is a work to promote change. Therefore, preferably, the above formula (7) is satisfied, and more preferably, the above formula (8) is satisfied, so that many {002} planes can be obtained after the recrystallization annealing step, and more excellent bending characteristics can be obtained. it can.

Thus, the diffraction peak intensity ratio of each crystal plane, that is, the balance of the diffraction peak intensities has a great influence on the bending characteristics and bendability of the rolled copper foil. As will be described later, 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 during the final cold rolling process.

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

(Ingot preparation step S10)
As shown in FIG. 1, first, 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.

  The above-mentioned 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 process for obtaining a high bending property is performed, for example, also as a bonding process with an FPC base material. The heating temperature at the time of bonding is set in accordance with, for example, the curing temperature of a base material made of an FPC resin or the like, the curing temperature of an adhesive to be used, and the range of temperature conditions is wide and diverse. In order to adjust the softening temperature of the rolled copper foil to the heating temperature set in this way, an additive capable of adjusting the heat resistance of the rolled copper foil may be added.

  As an ingot used in the present embodiment, an ingot having no additive added, and an ingot added with several kinds of additives are exemplified in Table 1 below.

  Moreover, as a representative example of the additive which raises or lowers the heat resistance as the additive shown in Table 1 and other additives, for example, boron (B), niobium (Nb), titanium (about 10 ppm to 500 ppm) One or more elements of Ti), nickel (Ni), zirconium (Zr), vanadium (V), manganese (Mn), hafnium (Hf), tantalum (Ta), and calcium (Ca) were added. There is an example. Alternatively, there is an example in which Ag is added as the first additive element and any one or more of the above elements 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, the change of the temperature condition of the said copper material, an additive, and annealing process S32 according to this has little influence with respect to the effect of this 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 relieved by subjecting the plate material that has been cold-rolled and work hardened to an annealing treatment to anneal the plate material. By repeating this a predetermined number of times, a copper strip called “dough” is obtained. When an additive for adjusting heat resistance is added to the copper material, the temperature condition of the annealing treatment is appropriately changed according to the heat resistance of the copper material.

  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 process performed at the end of the repetition, the above-mentioned copper strip (fabric) is subjected to dough annealing treatment 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, it is preferable that the dough annealing step is performed under a temperature condition that can sufficiently relieve the processing distortion caused by each of the above steps, for example, a temperature condition substantially equivalent to a complete annealing treatment.

(Final cold rolling process S40)
Next, the final cold rolling step S40 is performed. The final cold rolling is also referred to as finish cold rolling, and cold rolling to be finished is applied to the annealed fabric a plurality of times. At this time, in order to obtain a rolled copper foil having high bending characteristics, the total workability is 90% or more, and more preferably, for example, the technique of Patent Document 3 is applied to this embodiment to 94% or more. Thereby, it becomes a rolled copper foil in which a higher bending rate is more easily obtained after the recrystallization annealing step.

Also, as the annealed dough becomes thinner each time cold rolling is repeated a plurality of times, for example, the technique of Patent Document 3 can be applied to gradually reduce the degree of processing per pass (one pass). preferable. Here, the degree of processing per pass follows the example of the total degree of processing, and the thickness of the workpiece before rolling of the n-th pass is T _Bn, and the thickness of the workpiece after rolling is T _An. Then, the degree of processing per pass (%) = [(T _Bn −T _An ) / T _Bn ] × 100.

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

In the final cold rolling step S40, it is preferable to control the position of the neutral point described below to move toward the outlet side of the roll every time cold rolling is repeated a plurality of times. That is, as described above, the speed of the workpiece whose magnitude relationship is reversed between the inlet side and the outlet side with respect to the rotational speed of the roll is the rotational speed of the roll at some position between the inlet side and the outlet side. Is equal to A position where both speeds are equal is called a neutral point, and the pressure applied to the workpiece is maximized at the neutral point.

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

  As described above, the balance of the diffraction peak intensity of each crystal plane has a great influence on the bending characteristics and bendability of the rolled copper foil, and the balance of the diffraction peak intensity of each crystal plane is mainly the final cold rolling. It is determined by the stress balance between compressive stress and tensile stress during the process.

  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 step and changes to the {022} plane in several paths. The larger the compressive stress, the easier it is to go through the {002} plane and the {113} plane, and the higher the tensile stress, the easier it is to go through the {111} plane and the {133} plane, respectively changing to the {022} plane.

  In other words, the above formulas (2) and (3) or the above formulas (5) and (6) have a low ratio of {111} plane and {133} plane in the rolled copper foil and a weak tensile stress. Is shown. In addition, looking at the above formula (1) or (4) alone indicates that the compressive stress is weak, but looking at the above formula (7) or (8) shows that the compressive stress is strong. Yes. Therefore, if these are judged comprehensively, it can be said that said Formula (1)-(8) prescribes | regulates the state with a strong compressive stress as a whole.

  Thus, by applying the final cold rolling step S40 in a state in which the compressive stress is superior to the tensile stress by controlling the degree of processing in each pass, the position control of the neutral point, and the like, the above formula (1 ) To (8), a rolled copper foil can be obtained. Therefore, after the recrystallization annealing step, a rolled copper foil having high bending characteristics 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 performed on the copper strip that has undergone the above steps. The rolled copper foil which concerns on this embodiment is manufactured by the above.

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

(Recrystallization annealing process (CCL process))
First, the rolled copper foil according to the present embodiment is cut into a predetermined size, and bonded to an FPC base material made of a resin such as polyimide to form a CCL (Copper Clad Laminate). At this time, either a method of forming a three-layer material CCL that is bonded using an adhesive or a method of forming a two-layer material CCL that is directly bonded without using an adhesive may be used. When an adhesive is used, the adhesive is cured by heat treatment, and the rolled copper foil and the base material are brought into close contact with each other to be integrated. When 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 the heating. 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.

  Specifically, the {022} plane that is the main orientation changes to the {002} plane. Therefore, the rolled copper foil excellent in the bending characteristic can be obtained.

  On the other hand, the {002} plane, {113} plane, {111} plane, and {133} plane, which are sub-azimuths, are ratios while maintaining the state after the final cold rolling process in the rolled copper foil manufacturing process. Will hardly change. Therefore, for rolled copper foil that has become hard due to work hardening, the effect of sub-azimuth is demonstrated in a form that is almost maximal by removing the influence of work hardening by the recrystallization annealing process, that is, by eliminating strain. Thus, a rolled copper foil having high bending properties and excellent bending resistance is obtained.

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

  Further, as described above, each crystal plane in the sub-direction hardly changes before and after the recrystallization annealing process. Therefore, in order to obtain high bending characteristics and bending resistance, the sub-azimuth of the rolled copper foil after the final cold rolling process and before the recrystallization annealing process may be controlled so as to satisfy the above relational expression.

(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. However, the additive is not limited to those listed in Ag and the 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 a high bending characteristic and bending resistance. it can. The thickness of the rolled copper foil may be greater than 20 μm depending on various uses including FPC use.

  Further, in the above-described embodiment, the total degree of work in the final cold rolling step S40 is set to 90% or more to obtain excellent bending characteristics, but bending resistance is obtained by adjusting the sub-oriented crystal plane. The technique can be used independently of this. In other words, when the bending resistance is particularly important and it is sufficient that a certain degree of bending property is obtained, the total degree of work in the final cold rolling process is set to less than 90% such as 85% and 70%, for example. Also good.

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

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

(1) Rolled copper foil using oxygen-free copper First, the rolled copper foil according to Examples 1 to 7 and Comparative Examples 1 to 7 using oxygen-free copper was manufactured as follows, and various evaluations were performed for each. .

(Production of rolled copper foil)
The rolled copper foil which concerns on Examples 1-7 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 150 ppm. However, about the comparative examples 1-7, the process etc. which remove | deviate a structure are 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 2 below shows analysis values of Ag concentration in the ingot, which were analyzed by an inductively coupled plasma (ICP) emission spectroscopic analysis method.

  As shown in Table 2, with respect to the target concentration of 150 ppm, the analytical values are 137 ppm to 165 ppm, all of which are suppressed to variations within about 150 ppm ± 15 ppm (10%). Ag is originally contained in the oxygen-free copper, which is the main raw material, in the range of several ppm to several tens of ppm as an inevitable impurity, and within about ± 15 ppm due to various causes such as variations in casting an ingot. This variation 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 700 ° C. to 800 ° C. for about 2 minutes. A copper strip (fabric) was produced by repeatedly performing the intermediate annealing step, and an annealed fabric was obtained in a fabric annealing step 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 137 ppm to 165 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 the above-mentioned embodiment, and the rolled copper foil which concerns on Examples 1-7 and Comparative Examples 1-7 was obtained. The conditions in the final cold rolling process are shown in Table 3 below.

  As shown in Table 3, the final cold rolling was performed by changing the conditions as shown in the right column in accordance with the reduction of the plate thickness sequentially from the upper stage to the lower stage. That is, the degree of processing per pass and the position of the neutral point of the cold rolling process with a thickness of 240 μm or less were changed. The position (mm) of the neutral point shown in the right column is indicated by the length from the end on the outlet side of the contact surface between the roll and the annealed material as the workpiece to the neutral point. Further, in order to obtain excellent bending characteristics, the conditions were set so that the total degree of work in the final cold rolling process was 95% in all of Examples 1 to 7 and Comparative Examples 1 to 7. By the above, the rolled copper foil which concerns on Examples 1-7 whose thickness is 12 micrometers and Comparative Examples 1-7 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 7 and Comparative Examples 1 to 7. The measurement concerned was performed on the conditions shown in the following Table 4 using the Rigaku Co., Ltd. X-ray-diffraction apparatus (model: Ultimate IV). As a representative, FIG. 2A shows the X-ray diffraction chart of Example 1, and FIG. 2B shows the X-ray diffraction chart of Comparative Example 1.

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. In Table 5 below, for the rolled copper foils according to Examples 1 to 7 and Comparative Examples 1 to 7, the diffraction peak intensity ratios I _{022} , I _{002} , and I _{{113} of} the respective crystal planes obtained as described above _. , I _{111} and I _{133} .

  For powdered copper, the relative intensities of standard diffraction peaks of each crystal plane were obtained from the description of the JCPDS card with card number: 40836. That is, the relative strengths 20, 46, 17, and 9 of each crystal plane {022} plane, {002} plane, {113} plane, and {133} plane with {111} plane as 100 were obtained.

  The relative intensity of the five diffraction peaks was converted to a ratio such that the total value was 100, and the diffraction peak intensity ratio of each crystal plane was determined for powdered copper.

Furthermore, the numerical value which concerns on said Formula (4)-(6) and (8) is calculated | required using the diffraction peak intensity ratio which concerns on the rolled copper foil shown in Table 5, and the diffraction peak intensity ratio which concerns on said powdered copper. It was. In the upper part of Table 6 below, the diffraction peak intensity ratios I _{0 {022}} , I _{0 {002}} , I _{0 {113}} , I _{0 {111}} , and I _{0 {133}} of each crystal plane of the powdered copper are shown. Indicates the value. Moreover, the numerical value which concerns on said Formula (4)-(6) and (8) calculated | required by the above is shown in the lower stage.

  As described above, in this example and the comparative example, the degree of processing per pass and the position of the neutral point in the final cold rolling process are changed. Thereby, at the time of cold rolling, the ratio of the stress component between the compression component and the tensile component applied to the workpiece is changed. As a result, the ratio of each crystal plane is changed, and the diffraction peak intensity ratio of each crystal plane shown in Table 5 and the numerical values related to the equations (4) to (6) and (8) shown in Table 6 are also changed.

  Moreover, as shown in Tables 5 and 6, in the combinations of the conditions of Examples 1 to 7, all the values from Formulas (1) to (8) are within the above-described predetermined range, and the recrystallization annealing step Later, it can be seen that a rolled copper foil capable of having excellent bending resistance as well as high bending properties is obtained.

  On the other hand, in the combination of the conditions of Comparative Examples 1 to 7, in any rolled copper foil, a plurality of values out of the respective values up to the formulas (1) to (8) are outside the above predetermined range. It can be seen that the rolled copper foil cannot have excellent bending resistance even after the recrystallization annealing step. In Tables 5 and 6, values outside the above-mentioned predetermined range are shown in bold with underline.

(Bending fatigue life test)
Next, in order to investigate the bending characteristics of each rolled copper foil, a bending fatigue life test was performed to measure the number of repeated bending (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. 3 shows a schematic diagram of a general sliding bending test apparatus 10 including the FPC high-speed bending tester and the like.

  First, the rolled copper foil according to Examples 1 to 7 and Comparative Examples 1 to 7 was cut to a width of 12.5 mm and a length of 220 mm, and a sample piece F having a thickness of 12 μm was similar to the above-described recrystallization annealing step. Recrystallization annealing was performed at 300 ° C. for 60 minutes by the procedure and method. Such a condition imitates an example of the amount of heat that the rolled copper foil actually receives in close contact with the substrate in the CCL process of the printed wiring board.

  Next, as shown in FIG. 3, the rolled copper foil sample F was fixed to the sample fixing plate 11 of the sliding bending test apparatus 10 with screws 12. Subsequently, the specimen piece F was brought into contact with and attached to the vibration transmission section 13, and the vibration transmission section 13 was vibrated in the vertical direction by the oscillation driver 14 to transmit the vibration to the specimen piece F, and a bending fatigue life test was performed. . The measurement conditions for the bending fatigue life were a bending radius R of 1.5 mm, a stroke S of 10 mm, and an amplitude number of 25 Hz. Under such conditions, five sample pieces F 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 7 below.

  As described above, each rolled copper foil has undergone a final cold rolling process in which the total degree of work is 95%, and as shown in Table 7, in any of Examples 1 to 7 and Comparative Examples 1 to 7 The bending fatigue life, that is, the number of bendings was 1 million times or more, and excellent bending characteristics were obtained.

(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. Then, the bending test which measures the frequency | count of bending until a crack arises in each rolled copper foil with the method shown in FIG. 4 was done.

  That is, first, the sample copper F obtained by cutting the rolled copper foils according to Examples 1 to 7 and Comparative Examples 1 to 7 into a width of 20 mm and a length of 40 mm with respect to the rolling direction was subjected to recrystallization annealing at 300 ° C. for 60 minutes. gave. Next, as shown in FIG. 4, the sample piece F 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 check for 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 the five sample pieces F cut out from each rolled copper foil, the cycle was repeated until the crack occurred while observing the bent portion every cycle, and the number of bending was measured. Table 8 below shows the results.

  As shown in Table 8, in any of Examples 1 to 7, the number of bendings was 50 times or more, and excellent bending resistance was obtained. On the other hand, in any of Comparative Examples 1 to 7, the number of bendings was less than 50, and sufficient bending resistance was not obtained.

(2) Rolled copper foil using tough pitch copper Next, using a tough pitch copper to which Ag with a target concentration of 200 ppm was added, and using a procedure and method similar to those of the above-described example, Example 8 having a thickness of 12 μm and A rolled copper foil according to Comparative Example 8 was produced. However, the comparative example 8 includes a process that deviates from the configuration.

Ag concentrations in the ingots of Example 8 and Comparative Example 8 were analytical values obtained by IPC emission spectroscopic analysis, and were 195 ppm and 205 ppm, respectively. In addition, in accordance with the heat resistance of the tough pitch copper material containing Ag of such concentration, conditions different from the above were used in the intermediate annealing step and the dough annealing step. Specifically, the intermediate annealing step was held at a temperature of 650 ° C. to 750 ° C. for about 1 minute, and the dough annealing step was held at a temperature of about 700 ° C. for about 2 minutes.

  About the rolled copper foil which concerns on Example 8 and Comparative Example 8 which were produced as mentioned above, the X-ray-diffraction measurement by 2 (theta) / (theta) method was performed with the method and procedure similar to the above-mentioned Example. As a result, for the rolled copper foil according to Example 8, the relationship between the diffraction peak intensities of the crystal planes was within a predetermined range from formulas (1) to (8). On the other hand, with respect to the rolled copper foil according to Comparative Example 8, the numerical values according to the expressions (1) and (2) were larger than 6.0, and the result was out of the predetermined range. Moreover, in Formula (4), it was larger than 0.70, and in Formula (5), it was larger than 0.12, and was outside the predetermined range.

  Moreover, the bending fatigue life test was done to the rolled copper foil which concerns on Example 8 and Comparative Example 8 with the method and procedure similar to the above-mentioned Example. As a result, each rolled copper foil has undergone a final cold rolling process in which the total degree of work is 95%, and excellent bending characteristics of 1 million times or more can be obtained in both Example 8 and Comparative Example 8. It was.

  Moreover, the bending test was done to the rolled copper foil which concerns on Example 8 and Comparative Example 8 with the method and procedure similar to the above-mentioned Example. As a result, in Example 8, the number of folding was as good as 66, whereas in Comparative Example 8, the number of folding was 34, which was insufficient.

  From the above, it was found that if each crystal plane is within a predetermined range, good bending characteristics and bendability can be obtained also for a rolled copper foil mainly made of tough pitch copper.

(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 Example 9 and Comparative Example 9 whose thickness is 12 micrometers was manufactured with the same procedure and method. However, the comparative example 9 includes a process that deviates from the configuration.

  The Ag concentrations in the ingots of Example 9 and Comparative Example 9 were 125 ppm and 124 ppm, respectively, as analytical values obtained by IPC emission spectroscopic analysis. Ti concentrations were 41 ppm and 40 ppm, respectively. The variations are all within ± 10%, and are common in the field of metal materials.

  In addition, in accordance with the heat resistance of the oxygen-free copper material containing Ag and Ti at the above concentrations, conditions different from the above 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 700 ° C. for about 1 minute, and the dough annealing step was held at a temperature of about 700 ° C. for about 2 minutes.

  About the rolled copper foil which concerns on Example 9 and Comparative Example 9 which were produced as mentioned above, the X-ray-diffraction measurement by 2 (theta) / (theta) method was performed with the method and procedure similar to the above-mentioned Example. As a result, regarding the rolled copper foil according to Example 9, the relationship between the diffraction peak intensities of the crystal planes was within a predetermined range from formulas (1) to (8). On the other hand, about the rolled copper foil which concerns on the comparative example 9, the numerical value which concerns on Formula (2) became larger than 6.0, and became the result of having remove | deviated from the predetermined range. Moreover, in Formula (5), it was larger than 0.12, and it was smaller than 0.30 in Formula (8), and it was out of the predetermined range.

  Moreover, the bending fatigue life test was done to the rolled copper foil which concerns on Example 9 and Comparative Example 9 with the method and procedure similar to the above-mentioned Example. As a result, each rolled copper foil has undergone a final cold rolling process in which the total degree of work is 95%. In both Example 9 and Comparative Example 9, excellent bending characteristics of 1 million times or more are obtained. It was.

  Moreover, the bending test was done to the rolled copper foil which concerns on Example 9 and Comparative Example 9 with the method and procedure similar to the above-mentioned Example. As a result, in Example 9, the number of folding was as good as 71, whereas in Comparative Example 9, the number of folding was 35, which was insufficient.

  From the above, it was found that if each crystal plane is within a predetermined range, good bending characteristics and bendability can be obtained even for a rolled copper foil to which different additives such as Ag and Ti are added.

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

(1) About the principle of imparting bending resistance From the knowledge of crystal orientation, knowledge of metallurgy, and previous experimental experience, the inventors obtained bending resistance by controlling the crystal plane in the sub-orientation. The following considerations were made on the principles that can be used.

  According to the present inventors, it is considered that the bending resistance obtained in the present invention is related to the change in the main orientation and the non-change in the sub-direction before and after the recrystallization annealing process. As described above, in the recrystallization annealing step, the {022} plane that is the main orientation becomes the {002} plane after recrystallization. On the other hand, the {002} plane, {113} plane, {111} plane, and {133} plane, which are the sub-directions, remain substantially unchanged after recrystallization, and these sub-directions and the main direction after recrystallization The angle formed by the {002} plane, which is the crystal plane, is considered to be involved in the bending resistance.

Recrystallized {002} face {113} face: 25.2 °
Recrystallized {002} face {111} face: 54.7 °
Recrystallized {002} face {133} face: 46.5 °

  When the rolled copper foil according to the present application is in the state before the recrystallization annealing after the final cold rolling step, the above formulas (1) to (3) are within a predetermined range. All the ratios are kept low, meaning that there are few crystal planes with a large angle with the {002} plane even after recrystallization. Among other things, when the ratio of crystal faces having a large angle becomes a predetermined numerical value or less, it means that the effect of improving the bending resistance appears.

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

  FIG. 5 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. 5, the copper crystal in the copper material rotates toward the {111} plane only by tensile deformation, and rotates toward the {011} plane only by compression deformation. In rolling, since the compression component and the tensile component are deformed, the crystal rotation direction is not so simple. However, since the compressive component prevails over the tensile component and deforms and is rolled, the crystal rotation toward the {011} plane generally takes place, and the {111} plane changes depending on the ratio of the compressive component and the tensile component. Also try to rotate partly. At this time, since the compression component is dominant, crystal rotation is also caused in which the crystal that has been rotated to the {111} plane returns to the {011} plane. On the contrary, when a crystal rotating toward the {011} plane or a crystal reaching the {011} plane rotates toward the {133} plane or the {111} plane due to the tensile component There is also.

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

  Here, FIG. 6 shows that only the crystal planes of the specific orientation are distributed, but this is due to the following reason. Since copper has a face-centered cubic crystal, X-ray diffraction measurement by the 2θ / θ method does not appear as a diffraction peak unless h, k, and l on the {hkl} plane are all odd or even values. This is because if h, k, and l are a mixture of odd and even values, the diffraction peak disappears due to the extinction rule and measurement is impossible. Therefore, in showing the configuration of the rolled copper foil according to the above-described embodiment etc., the {001} plane ({002} plane), {113} plane, {111} plane, and {133} plane appearing as diffraction peaks. Stipulated. Since the effect of this configuration is obvious from the results of the above-described Examples and the like, it can be said that it is sufficient to consider the sub-oriented crystal planes listed above.

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

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

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

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

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

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

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

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

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

  The parameter at the time of calculation of the above formula (C) is the control factor, but among these, a plurality of types of control methods can be considered depending on how to select a fixed one or a variable one. . In the above-described embodiments and examples, the position of the neutral point is controlled using the degree of machining as a variable control factor, but control using a control factor other than the degree of machining is also possible.

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

DESCRIPTION OF SYMBOLS 10 Sliding and bending test apparatus 11 Sample fixing plate 12 Screw 13 Vibration transmission part 14 Oscillation drive body 20 Spacer F Sample piece

Claims (8)

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 _{113} ≦ 6.0,
I _{111} ≦ 6.0, and
Rolled copper foil characterized by I _{133} ≦ 6.0. Standard diffraction peaks of each crystal plane described in the JCPDS card or ICDD card for powdered copper having a {022} plane, a {002} plane, a {113} plane, a {111} plane, and a {133} plane The diffraction peak intensity ratios of the crystal planes calculated from the relative intensities and converted so that the total value becomes 100 are I _{0 {022}} , I _{0 {002}} , I _{0 {113}} , I _{0 {111, respectively. } And} I _{0 {133}} ,
I _{113} / I0 _{113} ≦ 0.70,
I _{111} / I0 _{111} ≦ 0.12, and
It is I _{133} / I0 _{133} <= 1.3, The rolled copper foil of Claim 1 characterized by the above-mentioned. The rolled copper foil according to claim 1, wherein I _{002} ≧ 7.5. Standard diffraction peaks of each crystal plane described in the JCPDS card or ICDD card for powdered copper having a {022} plane, a {002} plane, a {113} plane, a {111} plane, and a {133} plane The diffraction peak intensity ratios of the crystal planes calculated from the relative intensities and converted so that the total value becomes 100 are I _{0 {022}} , I _{0 {002}} , I _{0 {113}} , I _{0 {111, respectively. } And} I _{0 {133}} ,
It is I _{002} / I0 _{002} > = 0.30, The rolled copper foil in any one of Claims 1-3 characterized by the above-mentioned. 5. The rolled copper foil according to claim 1, comprising oxygen-free copper as defined in JIS C1020 or tough pitch copper as defined in JIS C1100 as a main component. The rolled copper foil according to any one of claims 1 to 5, wherein at least one of silver, boron, titanium, and tin is added.   The rolled copper foil according to any one of claims 1 to 6, wherein a thickness is 20 µm or less by the final cold rolling step having a total workability of 90% or more. It is an object for flexible printed wiring boards, The rolled copper foil in any one of Claims 1-7 characterized by the above-mentioned.

Images