KR20130129053A - Rolled copper foil - Google Patents

Abstract

The present invention provides a rolled copper foil with high curving resistance and high bending resistance. The rolled copper foil includes a main surface and multiple crystal surfaces, which are parallel to the main surface and comprises a {022} surface, a {002} surface, a {113} surface, a {111} surface, and a {133} surface. The diffraction peak ratios of the respective crystal surfaces are calculated from x-ray diffraction measurement using a 2θ/θ method applied on the main surface, are converted into 100 of a sum value thereof, and satisfy a formula of I{022} + I{002} ≥ 75. In powdered copper having the {022} surface, the {113} surface, the {111} surface, the {133} surface, and the {002} surface, the diffraction peak ratios of the respective crystal surfaces and full widths at half maximum of diffraction peaks for the diffraction peak ratios of which the sum value is converted into 100 satisfy [(I{113} / I0{113}) X 竊�섭竊⑨서{113}] + [(I{111} / I0{111}) X 竊�섭竊⑨서{111}] + [(I{133} / I0{133}) X 竊�섭竊⑨서{133}] ≤ 1.5. The ten point average roughness of the main surface is less than or equal to 1.2 μm. [Reference numerals] (AA) Start a process for manufacturing rolled copper foil;(BB) Repeated process;(CC) (Repetition a predetermined number of times) repeated process;(DD) End the process for manufacturing rolled copper foil;(S10) Process for preparing an ingot;(S20) Hot rolling process;(S31) Cold rolling process;(S32) Annealing process;(S40) Final cold rolling process;(S50) Surface treatment process

Description

[0001] ROLLED COPPER FOIL [0002]

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

Flexible Printed Circuits (FPCs) are thin and highly flexible, so they have a high degree of freedom in the mounting form for electronic equipment and the like. Therefore, the FPC can be used as a digital versatile disk (DVD: Digital), a hard disk drive (HDD), or the like, in addition to a folded portion of a folding cellular phone, a moving part such as a digital camera and a printer head, Many of them are used for wiring of moving parts of disk-related devices such as a compact disk (CD) or a compact disk (CD). Therefore, a rolled copper foil used as an FPC or a wiring material thereof has been required to have a high bending property (high bending property), that is, an excellent bending resistance (bending resistance) that can withstand repeated bending.

The rolled copper foil for FPC is manufactured through processes such as hot rolling and cold rolling. The rolled copper foil is bonded to the base film (substrate) of an FPC made of a resin (resin) such as polyimide directly or through an adhesive in the subsequent FPC manufacturing process . The rolled copper foil on the substrate is subjected to surface processing (surface processing) such as etching to form a wiring. The bending resistance of the rolled copper foil remarkably improves in the state after annealing after softening by recrystallization rather than the hardened state after rolling and hardening after cold rolling. Therefore, for example, in the above-described manufacturing process of the FPC, the rolled copper foil after cold rolling is used to cut the rolled copper foil while avoiding deformation such as elongation or wrinkles, and is superimposed on the substrate. Thereafter, the rolled copper foil and the base material are brought into close contact with each other to be integrated by heating together with recrystallization annealing (recrystallization annealing) of the rolled copper foil.

A variety of studies have been made on a rolled copper foil excellent in bending resistance and a method for producing the same, on the premise of the above-mentioned manufacturing process of the FPC, and the surface of the rolled copper foil has a {002} As the surface develops, it has been reported that the bendability is improved.

For example, in Patent Document 1, the annealing immediately before the final cold rolling is performed under the condition that the average grain size of the recrystallized grains is 5 占 퐉 to 20 占 퐉. Also, the rolling degree of the final cold rolling is set to 90% or more. The strength of the {200} face of the rolled face obtained by X-ray diffraction in the state of being tempered so as to become a recrystallized structure (recrystallized structure) is denoted by I and the intensity of the {200} face of the fine powder copper obtained by X- 200} plane is I0, a cubic texture (I / I0 > 20) is obtained.

Further, for example, in Patent Document 2, the degree of development of the cube texture before final cold rolling is improved, and the degree of final cold rolling is set to 93% or more. Further, by performing the recrystallization annealing, a rolled copper foil having an integrated intensity (I / I0? 40) of a {200} plane and having a significantly improved cubic texture is obtained.

For example, in Patent Document 3, in the final cold rolling step, the total processing degree is set to 94% or more and the processing degree per one pass is controlled to 15% to 50%. Thus, after the recrystallization annealing, a predetermined grain orientation state (crystal grain orientation state) is obtained. That is, the in-plane orientation degree? Of the {111} plane relative to the {200} plane of the rolled surface obtained by X-ray diffraction pole figure measurement (X-ray diffraction pole point measurement) is 10 degrees or less. The ratio of the normalized diffraction peak intensity [a] of the {200} plane, which is the cubic texture of the rolled surface to the normalized diffraction peak intensity [b] of the crystal region of the twin crystal relationship of the {200} a] / [b]? 3.

As described above, in the prior art, the cube texture of the rolled copper foil is developed after the recrystallization annealing step by increasing the total degree of processing of the final cold rolling step, thereby improving the bending resistance.

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

On the other hand, in recent years, FPCs are folded and assembled in a small space in accordance with miniaturization and thinning of electronic devices. Particularly, in a panel portion of a smart phone or the like, an FPC formed on a wiring may be bent and assembled at 180 degrees. For this reason, there is an increasing demand for a rolled copper foil that has a small bending radius (bending radius) to allow bending resistance.

As described above, different requirements may arise for the bending resistance to withstand repeated bending and the bending bending to withstand a small bending radius in accordance with the difference in use or the like. In order to cope with these different demands, conventionally, rolled copper foils of different characteristics have been separately manufactured for each use. However, this situation can not be said to be efficient in terms of productivity, and there is a problem that the profitability is bad.

An object of the present invention is to provide a rolled copper foil which can have high bending resistance and excellent bending resistance after a recrystallization annealing step. When the rolled copper foil having both of these characteristics can be realized, it can be applied to both of the application of emphasis on flex resistance and the application of emphasis on bending resistance. Therefore, the production efficiency can be remarkably improved.

(A final cold rolling step) having a main surface (main surface) and having a plurality of crystal planes (crystal planes) parallel to the main surface, and as rolled copper before the recrystallization annealing step,

Wherein the plurality of crystal planes include {022} plane, {002} plane, {113} plane, {111} plane and {133}

The diffraction peak intensity ratios (diffraction peak intensity ratios) of the respective crystal planes obtained from the X-ray diffraction measurement (X-ray diffraction measurement) using the 2θ / θ method on the main surface so as to have a total value of 100 were defined as I { }, I {002}, I {113}, I {111} and I {133}

I {022} + I {002} > 75,

The relative diffraction peaks of the respective crystal planes described on the JCPDS card or the ICDD card for powder copper having {002} plane, {113} plane, {111} plane, and {133} The diffraction peak intensity ratios of the {113} plane, the {111} plane, and the {133} plane among the diffraction peak intensity ratios obtained from the intensity and the sum of the diffraction peak intensities of the respective crystal planes are 100, {113}, I0 {111}, and I0 {133}

(Half widths) of the diffraction peaks of the {113} plane, the {111} plane and the {133} plane obtained from the X-ray diffraction measurement on the main surface are FWHM {113}, FWHM {111 } And FWHM {133}

(I {113} / I0 {113}) X FWHM {113}] + [(I {111} / I0 {111}) X FWHM {111}] + X FWHM {133}] ≤ 1.5,

The surface roughness according to the ten-point average roughness (ten-point average roughness) of the main surface was 10 μm,

A rolled copper foil is provided.

According to the second aspect of the present invention,

Which is mainly composed of oxygen-free copper specified in JIS C1020 or tough pitch copper specified in JIS C1100

There is provided a rolled copper foil as described in the first aspect.

According to the third aspect of the present invention,

Silver, at least one of boron, titanium, and tin is added

There is provided a rolled copper foil as described in the first or second aspect.

According to the fourth aspect of the present invention,

And the thickness is 20 μm or less by the final cold rolling step in which the total processing degree is 90% or more

A rolled copper foil according to any one of the first to the seventeenth aspects is provided.

According to the fifth aspect of the present invention,

For flexible printed wiring board

There is provided the rolled copper foil according to any one of the first to fourth aspects.

According to the present invention, there is provided a rolled copper foil capable of providing excellent bending resistance and excellent bending resistance after a recrystallization annealing step.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a flowchart showing a manufacturing process of a rolled copper foil according to an embodiment of the present invention. FIG.
2 (a) is an X-ray diffraction chart of a rolled copper foil according to Example 2 of the present invention, and Fig. 2 (b) is a graph showing the X-ray diffraction pattern of the rolled copper foil of Comparative Example 2 (C) is an X-ray diffraction chart of a rolled copper foil according to Comparative Example 11. Fig.
3 is a schematic view of a sliding bending test apparatus for measuring the bending resistance of a rolled copper foil according to an embodiment of the present invention.
4 is a diagram showing an outline of a method of testing the bendability of a rolled copper foil according to an embodiment of the present invention.
5 (a) is an inverse pole diagram showing the direction of crystal rotation due to tensile deformation, (b) is an inverse pole diagram showing a crystal rotation direction due to compression deformation . ≪ / RTI >
6 is an inverse pole figure showing the crystal orientation of the rolled copper foil after the final cold rolling step and before the recrystallization annealing step.

≪ Knowledge obtained by the present inventors &

As described above, in order to obtain a rolled copper foil having excellent flex resistance (flex resistance) required for FPC applications, it is better to develop the cube orientation of the rolled surface. The inventors also conducted various experiments to increase the occupancy of the cubic azimuth. From the results of the experiments so far, if the {022} plane existing after the final cold rolling step (final cold rolling step) is tempered by recrystallization by the subsequent recrystallization annealing step (recrystallization annealing step) Plane, that is, a cubic orientation. That is, after the final cold rolling step and before the recrystallization annealing step, it is preferable that the {022} plane be the kitchen orientation (main orientation).

On the other hand, as described in the above Patent Documents 1 to 3, and as attempted by the inventors of the present invention, even when a large number of cube aggregate structures are expressed, the {002} plane, which is a cube aggregate structure, occupies 100% in a rolled copper foil having a polycrystalline structure There is no case. This is also true before the recrystallization annealing step. In the state prior to the recrystallization annealing step, the {113} plane, the {111} plane, the {133} plane, etc., other than the {022} plane of the kitchen or the {002} plane of which crystal orientation is maintained before and after the recrystallization Is not controlled and a plurality of crystals are mixed. It is considered that the crystal grains (crystal grains) having a plurality of crystal planes thereof have various influences on various characteristics of the rolled copper foil. Therefore, the inventors of the present invention have focused attention on the crystal face of the unidirectional which has been considered to be unnecessary so far, and the properties of the rolled copper foil are improved by the crystal faces of these auxiliary orientations while maintaining high flex resistance without decreasing the occupancy rate on the kitchen And whether or not it can be increased.

In such a study, the present inventors proceeded to analyze the diffraction peaks (diffraction peaks) on the main surface of the rolled copper foil of each crystal face including the {113} plane, the {111} plane, the {133} . The diffraction peak indicates the presence of each of the two directions, and the occupancy of each of the two directions can be determined from the intensity ratio. As a result of such studies, the inventors of the present invention have found that even in a situation where predetermined bending properties are already obtained by controlling the {022} plane on the kitchen by variously defining the states of the diffraction peaks and controlling them I found something that could further improve my flexibility.

In addition to this, the inventors of the present invention have conducted intensive studies in order to obtain a rolled copper foil having a high bending resistance, which is required in FPC applications. As a result, it was found that not only the crystal orientation of the main surface of the rolled copper foil but also the state of the irregularities greatly affected the bendability.

The present invention is based on this finding found by the inventors.

≪ One embodiment of the present invention &

(1) Construction of rolled copper foil

First, the structure of the rolled copper foil according to one embodiment of the present invention will be described.

(Outline of rolled copper foil)

The rolled copper foil according to the present embodiment is, for example, in the form of a plate having a rolled surface as a main surface. This rolled copper foil can be produced, for example, by a method in which an ingot containing pure copper as a raw material such as oxygen-free copper (OFC: Oxygen-Free Copper) or TPC (Tough-Pitch Copper) And is a rolled copper foil after a final cold rolling step which is performed by a hot rolling step or a cold rolling step to a predetermined thickness and before a recrystallization annealing step.

The rolled copper foil according to the present embodiment is configured to be used, for example, as a flexible wiring material for FPC. That is, a total cold workability of not less than 90%, more preferably not less than 94%. As described above, such a rolled copper foil is desired to be provided with excellent bendability by performing a recrystallization annealing step, for example, a process of bonding an FPC and a substrate, and recrystallization.

The oxygen-free copper used as the raw material is a copper material having a purity of 99.96% or more as prescribed, for example, in JIS C1020, H3100 and the like. The oxygen content may not be completely zero, and may be, for example, several ppm or so. The tough pitch copper is, for example, a copper material having a purity of 99.9% or more specified by JIS C1100, H3100, or the like. In the case of tough pitch copper, the oxygen content is, for example, about 100 ppm to 600 ppm. In some cases, a rolled copper foil is prepared by adding a small amount of a predetermined additive such as silver (Ag) to these copper materials to form a dilute copper alloy (dilute copper alloy) and adjusting various characteristics such as heat resistance. The rolled copper foil according to the present embodiment can include both pure copper and a lean copper alloy and hardly affects the effect of the present embodiment by the copper material and the additive of the raw material.

When the thickness of the object to be processed (plate material of copper) before the final cold rolling step is TB and the thickness of the object to be processed after the final cold rolling step is TA, the total degree of processing (% ) = [(TB-TA) / TB] X 100. By setting the total working degree to not less than 90%, more preferably not less than 94%, a rolled copper foil excellent in flex resistance can be obtained.

(Crystal structure of rolled surface)

The rolled copper foil according to the present embodiment has a plurality of crystal planes parallel to the rolled surface. Concretely, in the state after the final cold rolling step and before the recrystallization annealing step, the {002} plane, the {002} plane, the {113} plane, the {111} plane and the {133} plane are included in the plurality of crystal planes. The {022} plane is on the upper side of the rolling surface, and each of the other crystal planes is a convex surface.

As described above, the state of each of these crystal planes is controlled by a proportional relation in which the states such as the diffraction peak intensity measured for each crystal plane are variously defined. The diffraction peak intensity of each crystal plane can be obtained from X-ray diffraction measurement (X-ray diffraction measurement) using the 2? /? Method on the rolled surface of the rolled copper foil.

It is the diffraction peak intensity ratio of each crystal plane that the diffraction peak intensities of the five crystal planes measured by the X-ray diffraction are converted into the ratio at which the total value is 100. This diffraction peak intensity ratio is approximately the same as the occupation rate of each crystal plane in the rolled surface.

From the diffraction peak intensity of each crystal plane, a conversion formula (A) for obtaining a diffraction peak intensity ratio of {022} plane as a representative is shown below. The diffraction peak intensities of the respective crystal planes are I '{022}, I {002}, I {113}, I {111} and I {133} , I '{002}, I' {113}, I '{111}, and I' {133}.

[Number 1]

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

I {022} + I {002}? 75 ... (One)

As for the states of diffraction peaks of the {113} plane, the {111} plane and the {133} plane which are the other crystal planes, the standard diffraction peak intensity ratio of copper and the half width of each diffraction peak .

The standard diffraction peaks of copper include, for example, diffraction peaks of powdered copper having {002} plane, {002} plane, {113} plane, {111} plane and {133} plane. For example, the Joint Committee for Powder Diffraction Standards (JCPDS) card (card number: 40836) or the International Center for Diffraction Data (ICDD) card describes the relative intensity of such diffraction peaks.

The relative intensity of standard diffraction peaks of these five crystal planes was converted into a ratio of 100, and the diffraction peak intensity ratio of each crystal plane was determined with respect to powdered copper (powdered copper) The diffraction peak intensity ratio can be set as a reference value.

A conversion formula (B) for obtaining the diffraction peak intensity ratio of {113} plane as a representative from the relative intensities of diffraction peaks of each crystal plane of powdered copper is shown below. I0 {002}, I0 {002}, I0 {113}, I0 {111} and I0 {133}, and the diffraction peak intensities of the respective crystal planes in powdered copper were I0 '{002}, I0' {002}, I0 '{113}, I0' {111}, and I0 '{133}.

[Number 2]

The FWHM {113}, FWHM {111} and FWHM (111) planes of the {113} plane, the {111} plane and the {133} plane of the rolled copper foil are respectively referred to as full width at half maximum (133), the above formula (1) is satisfied and, for example, the following formula (2) is established.

(I {113} / I0 {113}) X FWHM {113}] + [(I {111} / I0 {111}) X FWHM {111}] + X FWHM {133}] < = 1.5 ... (2)

As described above, the rolled copper foil according to the present embodiment is configured to have a high bending resistance that resists repeated bending after the recrystallization annealing process.

(Surface roughness of the rolled surface)

The rolled copper foil according to the present embodiment further comprises the following constitution in addition to the above-described constitution. That is, the rolled surface of the rolled copper foil according to the present embodiment has the following surface roughness (surface roughness) as 10-point average roughness (ten-point average roughness).

10 point average illuminance ≤ 1.2μm ... (3)

The 10-point average roughness referred to herein is one of the surface roughnesses defined by the JIS standard, and can be obtained from the roughness curve (illuminance curve) obtained by the roughness measurement. That is, the reference length is extracted from the roughness curve in the direction of the average line. A predetermined number of tops and valleys are measured in the direction of the vertical magnification from the average line of the extracted portion. At this time, the sum of the absolute values and average values of elevations of the valleys from the lowest valley to the fifth valley of the absolute values and average values of the altitudes of the highest peak to the fifth peak are obtained. The sum of these average values in micrometers (μm) is the 10-point average roughness.

That is, the 10-point average roughness referred to herein is a 10-point average roughness Rzjis according to JIS B 0601: 2001. However, there are variations in the display symbols of the surface roughness defined in the JIS standard, and a little confusion is likely to occur. Therefore, in the present specification, the symbol of Rzjis is not used and only "ten point average roughness" is written.

As described above, the rolled copper foil according to the present embodiment is configured to have a high bending resistance that resists repeated bending after the recrystallization annealing step, and an excellent bending resistance that resists a small bending radius.

(Properties of rolled copper foil)

The characteristics of the rolled copper foil having the crystal structure and surface roughness as described above will be described below.

As described above, the {022} plane before the recrystallization annealing process is changed to the {002} plane after the recrystallization annealing process, and the {002} plane before the recrystallization annealing process remains unchanged after the recrystallization annealing process, thereby improving the bending resistance of the rolled copper foil . Further, in the recrystallization annealing step, the {002} plane does not change its crystal orientation but becomes a seed crystal (seed crystal), and the {022} plane is changed to {002} plane to promote growth. Therefore, by satisfying the above-described formula (1) before the recrystallization annealing step, this effect can be sufficiently obtained.

The {113} plane, the {111} plane and the {133} plane of the other direction are unnecessary crystal planes which do not contribute to flexing resistance. That is, the {111} plane and the {133} plane mixed in the crystal interfere with the recrystallization of the {022} plane. In the above formula (2), the portion of I / I0 with respect to each crystal plane shows a difference in diffraction intensity peak ratio of each crystal plane from the standard diffraction peak intensity ratio of copper serving as a reference value. That is, the graph indicates the percentage of the occupation rate of each crystal plane in the rolled copper foil based on the powdered copper. If the numerical value of I / I0 is not more than a predetermined value, it indicates that these unnecessary crystal planes are small, and it can be said that the state is favorable for improvement of flex resistance.

The inventors of the present invention also paid attention to the processing distortion (processing distortion) of each crystal plane of recrystallization before recrystallization, and this processing distortion was defined by the half width of the diffraction peaks of each crystal plane in the above formula (2).

If processing distortions are accumulated on the {113} plane, the {111} plane, and the {133} plane mixed in the crystal, the recrystallization of the {022} plane is further disturbed. When the half-value widths FWHM {113}, FWHM {111} and FWHM {133} of the respective crystal planes are equal to or smaller than a predetermined value, the processing strain is small (not accumulated) in the state before recrystallization, It can be said that the recrystallization is in a state in which it is difficult to be inhibited.

The peak width of the diffraction peak equal to the half value width indicates the unevenness of the interval of the crystal face (lattice face) corresponding to the diffraction peak. This can be explained by the equation 2d · sin θ = nλ in Bragg equation. Where n is a positive integer, λ is the wavelength, d is the spacing of the lattice planes, and θ is the oblique angle (incidence angle) (incidence angle). The fact that the diffraction peak has a width means that the 2?, Furthermore, the viewing angle? Itself has a width, that is, a non-uniformity. On the other hand, in the Bragg equation, the positive integer n and the wavelength?, Which is the wavelength of the tube of the X-ray generator, are all constant when X-ray diffraction is measured under a certain condition. The fact that 2d 占 sin? Is constant even though there is nonuniformity in the viewing angle? Means that there is a variation in the interval d of the lattice planes.

As described above, even if the crystal of the same crystal plane (crystal orientation) is copper, the interval d of the lattice planes becomes different when the angle of view θ is different. The difference (unevenness) of the spacing d of the lattice planes comes from, for example, work distortion accumulated when the rolled copper foil is manufactured. Therefore, the narrower the half-value width of the diffraction peak, the smaller the deviation of the spacing d of the lattice planes becomes, and the smaller the processing strain accumulated in the crystal of the lattice planes becomes. On the other hand, the wider the half-value width of the diffraction peak, the larger the processing strain accumulated in the crystal of the lattice plane becomes.

Therefore, in order to suppress the ratio of the crystal planes of the {113} plane, the {111} plane, the {133} plane and the like to be low, and the three crystal planes It is possible to further improve the abrasion resistance of the rolled copper foil even in a situation where a high abrasion resistance is already obtained.

As described above, the balance of the diffraction peak intensity, that is, the diffraction peak intensity on each crystal plane greatly affects the crush resistance and bending resistance of the rolled copper foil. The balance of the diffraction peak intensities of the respective crystal planes is determined mainly by the stress balance between the compressive stress and the tensile stress in the final cold rolling step as will be described later.

Next, the surface roughness of the rolled copper foil will be described.

The inventors of the present invention have found that when the surface roughness of the rolled surface of the rolled copper foil is controlled to be a predetermined value or less, that is, when the above formula (3) is satisfied, in addition to the control of the diffraction peak intensity ratio of each crystal plane, Which can be improved. This is considered to be because when the rolled copper foil is folded and bent, the concave portion is deformed in the direction of opening so that cracking easily occurs at the starting point.

Here, since the surface roughness of the rolled surface is defined as the average value of ten-point average roughness which is the sum of the average values of the absolute values of the elevation of each of the top and valley portions, that is, the average value of the height difference of the irregularities on the rolled surface, the irregularities on the rolled surface can be accurately evaluated. That is, the greater the 10-point average roughness, the larger the unevenness of the rolled surface is, and the larger the 10-point average roughness is, the more cracks are generated starting from the depressed portion being pressed and lowered. Further, as the 10-point average roughness is smaller, the difference in unevenness of the rolled surface is small, and a rolled copper foil excellent in bending resistance can be obtained.

(2) Manufacturing method of rolled copper foil

Next, a method of manufacturing a rolled copper foil according to an embodiment of the present invention will be described with reference to Fig. 1 is a flowchart showing the manufacturing process of the rolled copper foil according to the embodiment.

(Preparation process (S10) of ingot)

First, as shown in FIG. 1, an ingot (ingot) is prepared by casting using pure copper such as oxy-free copper (OFC) or tough pitch copper as a raw material. The ingot is formed in a plate shape having a predetermined thickness and a predetermined width, for example. The pure copper such as oxygen free copper or tough pitch copper which is a raw material may be made of a rare copper alloy to which predetermined additives are added in order to adjust various characteristics of the rolled copper foil.

Various properties that can be adjusted by additives include, for example, heat resistance. As described above, in the rolled copper foil for FPC, the recrystallization annealing step for obtaining a high abrasion resistance is performed by, for example, a step of joining with a substrate of an FPC. The heating temperature at the time of bonding is set in conjunction with the curing temperature (curing temperature) of the substrate made of, for example, resin of FPC, the curing temperature of the adhesive to be used, and the like. In order to adjust the softening temperature of the rolled copper foil to the set heating temperature, an additive capable of adjusting the heat resistance of the rolled copper foil may be added.

The ingot to which the additive is not added and the ingot to which the additive is added are exemplified in Table 1 below as the ingot used in the present embodiment.

[Table 1]

(B), niobium (Nb), titanium (Ti), nickel (Ni), and the like, for example, about 10 ppm to 500 ppm are included in the additive material shown in Table 1 or other additive materials for raising or lowering the heat resistance. , Zirconium (Zr), vanadium (V), manganese (Mn), hafnium (Hf), tantalum (Ta) and calcium (Ca). Alternatively, there is an example in which Ag is added as the first additive element, and either one or a plurality of elements of these representative elements as the second additive element are added. In addition, it is possible to use a metal such as Cr, Zn, Ga, Ge, As, Cd, In, Sn, Au) may be added in a small amount.

Further, the composition of the ingot is maintained substantially in the rolled copper foil after the final cold rolling step (S40) described later. When the additive is added to the ingot, the ingot and the rolled copper foil have substantially the same additive concentration.

The temperature condition in the annealing step (S32) to be described later is appropriately changed in accordance with the heat resistance by the copper material and the additive. However, such changes in the copper material and the additive, and accordingly the temperature condition of the annealing step (S32) have little effect on the effect of the present embodiment.

(Hot rolling step (S20))

Next, the prepared ingot is subjected to hot rolling to obtain a plate having a thickness smaller than a predetermined thickness after casting.

(Repeating step (S30))

Subsequently, the cold rolling step (S31) and the annealing step (S32) are repeated a predetermined number of times (S30). That is, annealing is performed on a plate material subjected to work hardening by cold rolling, and annealing is performed to alleviate work hardening. By repeating this for a predetermined number of times, copper (copper cloth) called "dough" (dough) is obtained. When an additive or the like for adjusting the heat resistance is added to the copper material, the temperature condition of the annealing treatment is appropriately changed in accordance with the heat resistance of the copper material.

The annealing step (S32) during the repetition step (S30) is called "intermediate annealing step". The interval between the lattice planes of each crystal after the final cold rolling step (S40) described later, that is, the half-width of the diffraction peak of each crystal plane can be controlled by the number of repetitions of the intermediate annealing process.

The annealing step (S32) performed immediately before the final cold rolling step (S40), which will be described later, is referred to as a "final annealing step" or a "green sheet annealing step". In the green body annealing step, copper (green body) is subjected to green body annealing to obtain an annealed green body. Also in the green body annealing step, the temperature condition is appropriately changed in accordance with the heat resistance of the copper material. At this time, it is preferable that the green body annealing step is carried out under a temperature condition capable of sufficiently alleviating the work distortion caused by each of the above-described steps, for example, a temperature condition substantially equivalent to the complete annealing treatment.

(Final cold rolling step (S40))

Then, a final cold rolling step (S40) is carried out. The final cold rolling is also referred to as finish cold rolling, and cold rolling, which is the final cold rolling, is performed on the annealed raw material several times to form a thin copper foil. At this time, the total working degree is set to 90% or more, more preferably 94% or more, so as to obtain a rolled copper foil having a high engraving property. As a result, after the recrystallization annealing step, the rolled copper foil is more likely to have better bending properties.

Further, as the annealed sheet becomes thinner each time the cold rolling is repeated several times, it is preferable that the processing degree per one pass (one pass) is gradually decreased. Here, according to the example of the total degree of processing, the thickness of the object to be processed before rolling on the n-th pass is TBn and the thickness of the object to be processed (processed object) after rolling is TAn, (%) Of sugar = [(TBn-TAn) / TBn] X 100.

By changing the degree of processing per pass as described above, the diffraction peak intensity ratio of each crystal plane of the rolled copper foil can be controlled.

That is, at the time of rolling processing, objects to be processed such as annealed raw paper are drawn into a gap between one rolls facing each other, for example, and drawn out to the opposite side, thereby reducing the thickness. The speed of the object to be processed is slower than the speed of rotation of the roll on the inlet side before being drawn into the roll and faster than the speed of rotation of the roll on the exit side after being drawn out of the roll. Therefore, the object to be processed is subjected to compressive stress at the entrance side and tensile stress at the exit side. In order to process the object to be processed thinly, compressive stress> tensile stress must be used. It is possible to adjust the ratio of the respective stress components (compression component and tensile component) on the premise that the compressive stress> tensile stress is adjusted by adjusting the degree of processing per pass.

In the final cold rolling step (S40), it is also possible to adjust the ratio of the stress component (compression component to tensile component) from the viewpoint of control of positional movement of the neutral point described below. That is, as described above, the speed of the object to be processed, in which the magnitude relationship between the entrance side and the exit side is reversed with respect to the rotation speed of the roll, becomes equal to the rotation speed of the roll at a position somewhere between the entrance side and the exit side. The position at which the velocity is the same is referred to as the neutral point, and the pressure applied to the object at the neutral point is the maximum.

The position of the neutral point is determined by the front tension, the back tension, the rolling speed (the rotational speed of the roll), the roll diameter, the processing degree, the rolling load, and the like Can be controlled by adjusting the combination. That is, the ratio of compressive stress and tensile stress can be adjusted by controlling the position of the neutral point.

The balance of the diffraction peak intensities of the respective crystal planes is mainly determined by the stress balance of the compressive stress and the tensile stress in the final cold rolling step.

Concretely, during the rolling process such as the final cold rolling step (S40), the copper crystals in the copper material rotate due to the stress during the rolling process, and change to {022} in several paths. The larger the compressive stress is, the easier it is to pass through the {002} plane or the {113} plane, and the larger the tensile stress becomes, the more easily the {111} plane or the {133} plane is passed. And are changed into {022} faces, respectively. Crystals that have not reached the {022} plane or crystals that have reached the {022} plane but have been rotated by the {111} plane or the {133} plane due to the tensile stress become diagonal.

By thus changing the stress balance between the compressive stress and the tensile stress, it is possible to adjust the balance of the diffraction peak intensity at the crystal face of the diagonal direction. The balance of the diffraction peak intensities of these crystal planes greatly affects the bending resistance and bending resistance of the rolled copper foil as described above.

Further, in the final cold rolling step (S40), it is preferable to use a rolling roll whose surface roughness is 0.075 mu m or less in arithmetic average roughness Ra.

The surface roughness of the rolled roll affects the stress balance of the above compressive stress and 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. And a rolled copper foil whose surface roughness satisfies the above-described formula (3) can be obtained. In addition, the arithmetic average roughness (Ra) referred to herein is one of the surface roughnesses defined by JIS B 0601: 2001. Specifically, it is a value obtained by extracting from the roughness curve by the reference length in the direction of the average line, and averaging the absolute values of the deviations from the average line of the extracted portion to the measurement curve.

(1) to (3) by performing the final cold rolling step (S40) while controlling the degree of processing degree in each of the passes, controlling the position of the neutral point, controlling the surface roughness of the rolling roll, Can be obtained. Therefore, after the recrystallization annealing step, a rolled copper foil having high bending resistance against repeated bending and excellent bending resistance against small bending radius is obtained.

(Surface treatment step (S50))

The copper foil subjected to the above-described steps is subjected to a predetermined surface treatment. Thus, the rolled copper foil of the present embodiment is produced.

(3) Manufacturing Method of Flexible Printed Circuit Board

Next, a method of manufacturing a flexible printed wiring board (FPC) using a rolled copper foil according to an embodiment of the present invention will be described.

(Recrystallization annealing step (CCL step))

First, the rolled copper foil according to the present embodiment is cut to a predetermined size and bonded to a base material of an FPC made of resin such as polyimide to form a CCL (Copper Clad Laminate). At this time, either of the method for forming the three-layered CCL to be bonded through the adhesive and the method for forming the two-layered CCL to be bonded directly without passing through the adhesive may be used. In the case of using an adhesive, the adhesive is cured by a heat treatment so that the rolled copper foil and the base material are closely contacted and integrated. When the 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 may be appropriately selected in accordance with the adhesive or the curing temperature of the substrate, and may be, for example, from 1 minute to 120 minutes at a temperature of from 150 DEG C to 400 DEG C.

As described above, the heat resistance of the rolled copper foil is adjusted 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 for bonding the rolled copper foil to the substrate also serves as a recrystallization annealing process for the rolled copper foil. The rolled copper foil is subjected to a recrystallization annealing step to obtain a rolled copper foil having a recrystallized structure. That is, the rolled copper foil has high bending resistance and excellent bending resistance.

In addition, the CCL process also serves as a recrystallization annealing step. Thus, 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 step, Deformation such as elongation, wrinkle and bending can be made less likely to occur.

In addition, each crystal plane of the cubic phase is hardly changed before and after the recrystallization annealing process. Therefore, in order to obtain the bending resistance and the bending resistance, the bending of the rolled copper foil after the final cold rolling step and before the recrystallization annealing step may be controlled so as to satisfy the above relational expression.

(Surface processing step)

Next, the rolled copper foil bonded to the substrate is subjected to a surface processing step. In the surface processing step, a surface of the rolled copper foil is subjected to a wiring forming step of forming a copper wiring or the like using a method such as etching and a surface treatment such as a plating treatment in order to improve the connection reliability between the copper wiring and the other electronic member A protective film forming step of forming a protective film such as solder resist or the like so as to cover a part of the copper wiring is carried out in order to protect the copper wiring and the like.

Thus, an FPC using the rolled copper foil according to the present embodiment is manufactured.

≪ Another embodiment of the present invention >

The embodiments of the present invention have been described above in detail. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

For example, in the above 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 Ag or the above-mentioned representative examples. The various properties adjustable by the additive are not limited to heat resistance, and the additive may be appropriately selected depending on various properties requiring adjustment.

Further, in the above 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 a process different from the CCL process.

Further, in the above embodiment, the rolled copper foil is used for the FPC application, but the use of the rolled copper foil is not limited to this and can be used for applications requiring bending resistance and bending resistance. The thickness of the rolled copper foil may be more than 20 占 퐉 depending on various applications including FPC applications.

In addition, in order to obtain the effect of the present invention, not all of the above-described steps are necessary. The various conditions of the above-described embodiment and the embodiments to be described later are merely illustrative and can be appropriately changed.

[Example]

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

(1) Rolled copper foil using oxygen free copper

First, the rolled copper foils of Examples 1 to 7 and Comparative Examples 1 to 15 using oxygen-free copper were prepared as follows, and various evaluations were made for each.

(Production of rolled copper foil)

Rolled copper foil of Examples 1 to 7 and Comparative Examples 1 to 15 was produced in the same procedure and the same manner as in the above-mentioned embodiment, using oxygen-free copper with Ag added thereto at a target concentration of 200 ppm. However, in the case of Comparative Examples 1 to 15, processing for deviating from the configuration is included.

Specifically, an ingot having a thickness of 150 mm and a width of 500 mm was prepared by dissolving a predetermined amount of Ag in oxygen-free copper and pouring it. The analytical values of the Ag concentration in the ingot are shown in Table 2 below by analysis by high frequency inductively coupled plasma (ICP: Inductively Coupled Plasma) emission spectrometry.

[Table 2]

As shown in Table 2, the analytical value was 180 ppm to 218 ppm, and the deviation was within 200 ppm ± 20 ppm (10%) for the target concentration of 200 ppm. Ag may be contained in an amount of from about ppm to about 10 ppm as an inevitable impurity in anoxic copper, which is a main raw material, and may be contained in an amount of about 20 ppm or less, depending on various causes such as pouring Unevenness is common in the metal materials field.

Next, a plate material having a thickness of 8 mm was obtained by a hot rolling process in the same order and in the same manner as in the above-described embodiment, and then subjected to a cold rolling step and an intermediate annealing step of maintaining the temperature at a temperature of 750 to 850 degrees for about 2 minutes, (Raw paper) having a thickness of 0.6 mm was produced. Followed by holding at a temperature of about 750 DEG C for about 2 minutes to obtain an annealed green sheet.

Here, the temperature conditions and the like of each annealing step are adjusted to the heat resistance of the oxygen-free copper material containing 180 ppm to 218 ppm of Ag. The reason why different temperature conditions are used for the copper materials having the same composition for each annealing step is that the heat resistance changes depending on the thickness of the copper material and the temperature can be lowered when the copper material is thin.

Finally, the final cold rolling step was carried out in the same procedure and the same manner as in the above-described embodiment to obtain rolled copper foils for Examples 1 to 7 and Comparative Examples 1 to 15. The conditions of the final cold rolling process are shown in Table 3 below.

[Table 3]

As shown in Table 3, as the thickness of the plate gradually decreased from the top to the bottom of each table, the conditions were changed as in the case of the right side and the final cold rolling was performed. That is, the thickness was 200 μm or less, and the processing degree per one pass of the cold rolling was changed. That is, at this time, the position of the neutral point also changes. Rolling rolls having surface roughness, that is, arithmetic mean roughness Ra of small, were used in Examples 1 to 7, and rolling rolls having a large arithmetic mean roughness Ra were used in Comparative Examples 1 to 15.

In addition, in all of Examples 1 to 7 and Comparative Examples 1 to 15, conditions were set so that the total working degree of the final cold rolling step was 94% in order to obtain excellent bending resistance. Concretely, the total processing degrees of Examples 1 to 7 and Comparative Examples 1 to 15 were set to 98%. Thus, rolled copper foils of Examples 1 to 7 and Comparative Examples 1 to 15 having a thickness of 12 占 퐉 were produced.

Next, each rolled copper foil produced as described above was evaluated as follows.

(X-ray diffraction measurement by the 2? /? Method)

First, the rolled copper foils of Examples 1 to 7 and Comparative Examples 1 to 15 were subjected to X-ray diffraction measurement by the 2? /? Method. These measurements were carried out under the conditions shown in Table 4 below using an X-ray diffractometer (type: Ultima IV) of Rikaku Co., 2 (a) and 2 (b) show X-ray diffraction charts of Example 2 and Comparative Examples 2 and 11, respectively.

[Table 4]

Next, the diffraction peak intensities of the {022} plane, the {002} plane, the {113} plane, the {111} plane and the {133} plane of the copper crystals measured by the 2θ / , And the diffraction peak intensity ratio of each crystal plane was determined. The value of the above equation (1), that is, the value of (I {022} + I {002}) was obtained. I {002}, I {002} and I {113} of the respective crystal planes obtained as described above were measured for the rolled copper foils of Examples 1 to 7 and Comparative Examples 1 to 15 in the following Table 5. [ , I {111}, I {133}, and the value of equation (1).

[Table 5]

Further, relative to the powdered copper, the relative intensity of standard diffraction peaks of each crystal plane identical to each of the above-mentioned crystal planes was obtained from the base of the JCPDS card of the card number: 40836. The respective relative intensities 20, 46, 17, and 9 of the {002} plane, the {002} plane, the {113} plane, and the {133} plane were obtained.

The relative intensities of these five diffraction peaks were converted into a ratio of 100 and the diffraction peak intensity ratio of each crystal plane to the powdered copper was obtained.

Further, the numerical values of I / I0 with respect to the above formula (2) were obtained using the diffraction peak intensity ratio of the rolled copper foil and the diffraction peak intensity ratio of copper powder shown in Table 5. I0 {002}, I0 {113}, I0 {111} and I0 {133} of the diffraction peak intensity ratios of the respective crystal planes of the powdered copper are shown at the top of Table 6 below. In the lower part, numerical values of I / I0 with respect to the equation (2) obtained as described above are shown.

[Table 6]

From the X-ray diffraction charts of Examples 1 to 7 and Comparative Examples 1 to 15, the half width of the diffraction peaks of each crystal plane was determined. Table 7 below shows the values of these half-value widths FWHM {113}, FWHM {111} and FWHM {133}. The numerical values of the above formula (2) are shown on the right end of Table 7.

[Table 7]

As described above, the present embodiment and the comparative example change the processing degree and the position of the neutral point per one pass of the final cold rolling step. The surface roughness of the rolled roll was changed in Examples and Comparative Examples. As a result, the ratio of the compressive component to the stress component of the tensile component is changed in the cold rolling process. As a result, the ratio of each crystal plane changed, and the diffraction peak intensity ratio of each crystal plane shown in Table 5, the numerical value of each I / I0 shown in Table 6, the half value width shown in Table 7, It is changing.

As shown in Tables 5 and 7, the values of the equations (1) and (2) were all within the above-mentioned ranges in the combination of the conditions of Examples 1 to 7.

On the other hand, in the combination of the respective conditions of Comparative Examples 1 to 15, one or both of the values of the formulas (1) and (2) in some rolled copper foils were out of the predetermined range. Values out of the predetermined range in Tables 5 and 7 are indicated by underlined bold letters.

(10 point average roughness measurement)

Subsequently, 10-point average roughness was measured in order to examine the surface roughness of the rolled copper foils of Examples 1 to 7 and Comparative Examples 1 to 15. For this measurement, a surface roughness meter (model: SE500) manufactured by Kosaka Laboratory Co., Ltd. was used. As the measurement conditions, the diameter of the stylus was 2 m, the measurement speed was 0.2 mm / sec, the measurement length was 4 mm, the extracted reference length was 0.8 mm, and the load was 0.75 mN or less. The measurement results are shown in Table 8 below.

[Table 8]

As described above, in this embodiment and the comparative example, a rolling roll having different surface roughness, that is, different arithmetic average roughness Ra, is used in the final cold rolling step. Therefore, as shown in Table 8, the surface of the rolled copper foil was comparatively flattened in the combination of the conditions of Examples 1 to 7, and the value of the formula (3) was within the above-mentioned predetermined range.

On the other hand, in the combination of the respective conditions of Comparative Examples 1 to 15, the value of the formula (3) was out of the predetermined range for some rolled copper foils. In Table 8, values out of the predetermined range are expressed in bold underlined letters.

Table 9 below shows the values of equations (1) to (3) in each rolled copper foil.

[Table 9]

As described above, it is necessary to satisfy the above-mentioned formulas (1) to (3) in order to further improve the high bending resistance and obtain the excellent bending resistance with respect to the rolled copper foil after the recrystallization annealing step. In Examples 1 to 7, both of the values of the above-mentioned formulas (1) to (3) are satisfied for any of the rolled copper foils. On the other hand, in Comparative Examples 1 to 15, any one or more of the above-mentioned formulas (1) to (3) in the rolled copper foil was out of a predetermined range.

(Bending fatigue life test)

Next, in order to investigate the bending resistance of each rolled copper foil, a bending fatigue life test (bending fatigue life test) was performed in which the number of repeated bending times (number of bending) until each rolled copper foil was broken was measured. These tests were performed using an FPC high-speed bending tester (type: SEK-31B2S) manufactured by Shin-Etsu Engineering Co., Ltd. and conforming to the IPC (American Printed Circuit Industry Association) standard. 3 is a schematic diagram of a general sliding bending test apparatus 10 including an FPC high-speed bending test machine manufactured by Shin-Etsu Engineering Co., Ltd. Fig.

First, the rolled copper foils of Examples 1 to 7 and Comparative Examples 1 to 15 were cut to a width of 12.5 mm and a length of 220 mm, and a specimen F having a thickness of 12 탆 was subjected to the recrystallization annealing process described above at 300 degrees 60 Minute recrystallization annealing was performed. These conditions follow an example of the amount of heat actually received by the rolled copper foil when it is brought into close contact with the substrate in the CCL process of the flexible printed wiring board.

3, a sample piece (F) of the rolled copper foil was fixed to a sample fixing plate (sample fixing plate) 11 of a sliding bending test apparatus 10 with a screw 12 as shown in FIG. Subsequently, the sample piece F is brought into contact with and attached to the vibration transmission portion 13, and the vibration transmission portion 13 is vibrated in the vertical direction by the oscillation drive body 14, And the flex fatigue life test was carried out. The bending fatigue life was measured under the conditions that the bending radius R was 1.5 mm, the stroke S was 10 mm, and the number of amplitudes was 25 Hz. Five pieces of the sample pieces F cut out from each rolled copper foil were measured under these conditions, and the average value of the number of times of flexing until fracture occurred was compared. The results are shown in Table 10 below.

[Table 10]

As shown in Table 10, in Examples 1 to 7 and Comparative Examples 1 to 3, since the above-mentioned formulas (1) and (2) were also satisfied, high bending resistance with a bending number of 2,000,000 or more was obtained. On the other hand, in Comparative Examples 4 to 15, which did not satisfy either or both of the above-mentioned expressions (1) and (2), all of the bending times were less than 2,000,000 times.

It should be noted that Comparative Examples 4 to 15 are originally provided with a comparatively high level of bending resistance. This is because, for example, the final cold rolling step having a total working degree of 94% or more, specifically, a total working degree of 98%, which has been performed in the above-described Patent Document 3 is performed. In Examples 1 to 7, it was also possible to further improve flex resistance by satisfying the above-described expressions (1) and (2).

(Evaluation of bending resistance)

Then, the bending resistance of each rolled copper foil was examined. As a general test standard for bendability, there is no standardization concerning bending of 180 degrees, which is also required for FPC applications, for example. Therefore, a bending test was performed to measure the number of bending times until breakage occurred in each rolled copper foil by the method shown in Fig.

First, the rolled copper foils of Examples 1 to 7 and Comparative Examples 1 to 15 were subjected to recrystallization annealing at 300 degrees for 60 minutes in a sample piece (F) having a width of 15 mm and a length of 100 mm cut out in the rolling direction. Next, as shown in Fig. 4, the sample piece F was bent 180 degrees so as to sandwich the spacer 20 having a thickness of 0.25 mm. In this state, the bent part was observed with a metallurgical microscope to confirm whether or not it was cracked. If there is no breakage, the rolled copper foil is returned from the bent state to the original unfolded state. The cycle was repeated until the breaking occurred, while observing the bending portion every five cycles of each sample piece (F) cut out from each rolled copper foil in one cycle, and the number of bending was measured. Table 11 below shows the results of comparing the average value of the number of bending times until breakage occurs.

[Table 11]

As shown in Table 11, in all of Examples 1 to 7, the number of bending was about 90 times or more, and excellent bending resistance was obtained.

On the other hand, in all of Comparative Examples 1 to 3 which exhibited excellent bending resistance, the number of bending was less than 50 times without satisfying the formula (3), and sufficient bendability was not obtained. In particular, when Examples 4 and 7 and Comparative Example 2 are compared with each other, it can be seen that there is a significant difference in the inner bending property between the inside and the outside of the numerical value range (? 1.2 m) defined by the formula (3) .

Also, in Comparative Examples 4 to 6 and 10 to 12 in which at least one of the formulas (1) and (2) and the formula (3) were not satisfied, sufficient bending resistance was not obtained. Further, in Comparative Examples 7 to 9 and 13 to 15, sufficient bending resistance could not be obtained even though the formula (3) was satisfied. In Comparative Examples 7 to 9 and 13 to 15, at least one of the equations (1) and (2) is not satisfied and it is presumed that a high level of bending resistance is obtained in order to improve the bending resistance .

(2) Rolled copper foil using tough pitch copper

Next, a rolled copper foil for Example 8 and Comparative Examples 16 and 17 having a thickness of 12 탆 was prepared by using tough pitch copper doped with Ag with a target concentration of 200 ppm and by the same procedure and by the same method as the above example. However, for Comparative Examples 16 and 17, processing for deviating from the constitution and the like are included.

Ag concentrations in the ingots of Example 8 and Comparative Examples 16 and 17 were 210 ppm, 205 ppm and 195 ppm, respectively, as obtained by IPC emission spectrometry. All of which are within ± 10%, and are common in the field of metal materials. Further, in accordance with the heat resistance of the tough pitch copper material containing Ag at such a concentration, conditions different from the above conditions were used for the intermediate annealing step and the green sheet annealing step. Specifically, the intermediate annealing step was maintained at a temperature of 650 to 750 degrees for about 2 minutes to 4 minutes, and the green body annealing step was maintained at a temperature of about 700 degrees for about 2 minutes.

The rolled copper foil of Example 8 and Comparative Examples 16 and 17 produced as described above was subjected to X-ray diffraction measurement by the 2? /? Method in the same manner and in the same manner as in the above example, , And (2) were obtained. As a result, for the rolled copper foil of Example 8, the relationship of the diffraction peak intensities of the respective crystal faces was within a predetermined range of each expression. On the other hand, for the rolled copper foil of Comparative Example 16, it deviated from the predetermined range of Formula (1). Also, with respect to the rolled copper foil of Comparative Example 17, none of the expressions (1) and (2) exceeded the predetermined range.

Further, the ten-point average roughness of the rolled copper foil of Example 8 and Comparative Examples 16 and 17 was measured, and it was found to be within the predetermined range of the formula (3) for Example 8. On the other hand, all of the comparative examples 16 and 17 deviate from the predetermined range of the formula (3).

The rolled copper foil of Example 8 and Comparative Examples 16 and 17 was subjected to a flex fatigue life test in the same manner and in the same manner as in the above Examples. As a result, with respect to Example 8 satisfying the above equations (1) and (2), a high bending resistance was obtained in which the number of flexing was 2,096,000 times and more than two million times. On the other hand, in Comparative Examples 16 and 17 in which either or both of the above-mentioned expressions (1) and (2) were not satisfied, the number of bending times was 1,571,000 times and 1,578,000 times, respectively.

The rolled copper foil of Example 8 and Comparative Examples 16 and 17 was subjected to bending tests in the same manner and in the same manner as in the above examples. As a result, in Example 8, the number of bending times was good in 94, while in Comparative Examples 16 and 17, the results were 39 and 40 times, respectively.

From the above, it has been found that, when the respective crystal planes are within a predetermined range, good rolling resistance can be obtained even for a rolled copper foil containing tough pitch copper as a main raw material, and the bending resistance can be improved.

(3) Rolled copper foil using other additives

Next, using Ag having the target concentration of 120 ppm and oxygen-free copper added with titanium (Ti) having a target concentration of 40 ppm as an additive were used, and in the same manner and in the same manner as in the above example, Rolled copper foils of Examples 18 and 19 were produced. However, in Comparative Examples 18 and 19, processing for deviating from the constitution and the like are included.

The Ag concentrations in the ingots of Example 9 and Comparative Examples 18 and 19 were 121 ppm, 119 ppm and 124 ppm, respectively, as obtained by IPC emission spectrometry. The Ti concentrations were 41 ppm, 41 ppm and 44 ppm, respectively. All of which are 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 these concentrations, conditions different from the above conditions were used for the intermediate annealing process and the raw material annealing process. Specifically, the intermediate annealing step was maintained at a temperature of 650 to 750 degrees for about 1 minute to 3 minutes, and the raw paper annealing step was maintained at a temperature of about 700 degrees for about 1 minute.

The rolled copper foil of Example 9 and Comparative Examples 18 and 19 prepared as described above was subjected to X-ray diffraction measurement by the 2? /? Method in the same manner and in the same manner as in the above Example, , And (2) were obtained. As a result, for the rolled copper foil of Example 9, the relationship of the diffraction peak intensities of the respective crystal faces was within the predetermined ranges of the formulas (1) and (2). On the other hand, with respect to the rolled copper foil of Comparative Example 18, all the expressions (1) and (2) were out of the predetermined range. And the rolled copper foil of Comparative Example 19 deviated from the predetermined range of Formula (2).

The rolled copper foil of Example 9 and Comparative Examples 18 and 19 was subjected to a flex fatigue life test in the same manner and in the same manner as in the above Examples. As a result, with respect to Example 9 in which the above-mentioned formulas (1) and (2) were satisfied together, a high bending resistance was obtained in which the number of flexing was 2,109,000 times and more than two million times. On the other hand, in Comparative Examples 18 and 19 in which either or both of the above-mentioned formulas (1) and (2) were not satisfied, the number of bending times was 1,544,000 times and 1,538,000 times, respectively.

The rolled copper foil of Example 9 and Comparative Examples 18 and 19 was subjected to bending tests in the same manner and in the same manner as in the above Examples. As a result, in Example 9, the bending number of times was good at 95, while that of Comparative Examples 18 and 19 was 41 times and 43 times behind, respectively.

From the above, it can be seen that when the crystal faces are within a predetermined range, the rolling resistance of the rolled copper foil to which other additive materials such as Ag and Ti are added is also excellent in bending resistance and bending resistance.

≪ Discussion by the present inventors &

The control by the inventors of the present invention and the control of the surface roughness of the rolled copper foil will be described below.

(1) About bending resistance

First of all, the inventors of the present invention have studied the principles of imparting further excellent bending resistance to the rolled copper foil by controlling the crystal face of the convex portion and the structure of the control of the crystal face of the convex portion in the manufacturing process of the rolled copper foil This will be described below.

(Principle of more excellent bending resistance)

The inventors of the present invention have studied the principle that the better bending resistance can be obtained by controlling the crystal face of the cuboid from the knowledge of crystal orientation, the knowledge of metallurgy, and the experience gained so far.

According to the inventors of the present invention and the like, it is considered that the high bending resistance obtained by the present invention relates to a change in the kitchen surface, a change in the shape of the kitchen, and a magnitude of the processing distortion of each crystal face before and after the recrystallization annealing process. As described above, the {022} plane in the kitchen in the recrystallization annealing step becomes the {002} plane after recrystallization. Further, the {002} plane before the recrystallization annealing process promotes the {002} plane to the {002} plane. On the other hand, the {002} plane, the {111} plane, the {111} plane and the {133} plane, which are the other planes, remain substantially unchanged even after recrystallization, and the angle formed with these planes and the {002} It can be considered that it is concerned with the bending resistance of the rolled copper foil.

Recrystallization {002} plane ∠ {113} Plane: 25.2 degrees

Recrystallization {002} plane ∠ {111} Plane: 54.7 degrees

Recrystallization {002} plane ∠ {133} Plane: 46.5 degrees

Thus, the {113} plane has an angular relationship of {002} plane with 25.2 degrees, the {111} plane has an angular relationship of 54.7 degrees with the {002} plane, . That is, the angle formed with the {002} plane after recrystallization is large. From this, it can be considered that the angle formed between these convex portions and the {002} plane, which is the crystal plane on the kitchen after recrystallization, contributes to the improvement of the excellent bending resistance.

The extra three crystal planes of these can be excluded. However, the rolled copper foil is polycrystalline, and there is a small amount of copper foil. Therefore, it is important to reduce the number of these three convex portions as much as possible and to reduce the processing strain accumulated on these three crystal planes by rolling as much as possible. On the other hand, on the {022} surface of the kitchen, it is important to accumulate processing distortion caused by the rolling copper foil as much as possible. This is because, in the recrystallization annealing step, the driving force of the recrystallization becomes the driving force in addition to the heat due to the heating treatment.

At this time, the heat due to the heat treatment is constant with respect to the kitchen top and the side direction, so that the driving force of the recrystallization of each crystal plane is different due to the difference in the magnitude of the work distortion. Since the {113} plane, the {111} plane, and the {133} plane of the diagonal direction are extra bearings, the working distortion effectively acts as a driving force for changing the {002} plane on the kitchen. The bigger the distortion, the more unnecessary it is. In other words, these crystal grains do not change their crystal faces even after recrystallization, but they are free from processing distortion during the recrystallization annealing step and are recrystallized. The release of work distortion from the bipedalism is the release of energy from the bipedalism, which is unnecessary energy. Therefore, there is a fear that the obstacle will be caused when the {022} plane of the kitchen is changed to the {002} plane.

Therefore, as described above, by reducing (reducing) the diffraction peak intensity ratio, that is, the occupation ratio, of the crystal planes of the unidirectional planes, and by reducing the processing distortion of the cuboids, obstacles in recrystallization growth on the kitchen are reduced, It is considered that the flexibility is improved.

(The structure of control of the crystal face of the diagonals)

As described above, during the rolling process such as the final cold rolling process, the copper material is subjected to a tensile stress that is weaker than compressive stress and compressive stress. Copper crystals in the rolled copper material cause a rotation phenomenon in the {022} plane due to the stress in the rolling process, and the orientation of the crystal planes parallel to the rolled surface is mainly a {022} . At this time, as described above, the path of rotation toward the {022} plane changes due to the ratio of compressive stress to tensile stress. This will be described with reference to FIG.

(A) is an inverse pole figure showing a direction of crystal rotation due to tensile deformation, (b) is an inverse pole figure of a reversed polynomial curve of a pure metal type cited from the following technical literature 1, Is an inverse pole figure showing the direction of crystal rotation by the magnetic pole. Also, in the reverse polarity diagram, the {002} plane is denoted by {001} plane and the {022} plane denoted by {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 represented by the {011} plane which is the minimum value of the plane parallel to the {022} plane.

2.52 (a), (c) of p96, Mar. 1, 1984, Mar. 20, 1984, Technical Document 1: Edited by Shinichi Nagashima,

As shown in Fig. 5, the copper crystals in the copper material rotate toward the {111} plane only by the tensile strain and rotate toward the {011} plane only by the compressive strain. The rolling direction of the rolling is not so simple, because the rolling and pressing components have a combined deformation of the compression component and the tensile component. However, since the compressive component predominates over the tensile component and is subjected to rolling, it usually tends to rotate the {111} surface by the ratio of the compressive component and the tensile component while causing crystal rotation toward the {011} plane. At this time, since the compression component is predominant, a crystal rotation in which the crystal that has started to rotate on the {111} plane is returned to the {011} plane also occurs. Conversely, on the other hand, a crystal rotating toward the {011} plane or a crystal reaching the {011} plane may be rotated toward the {133} plane or the {111} plane by the tensile component.

When crystal rotation occurs in such a manner that the compressive component and the tensile component maintain the relationship between the compressive component and the tensile component, the distribution of crystal planes of the upper and lower diagonals, as shown in the opposite pole diagram of FIG. 6, . As a result of the crystal rotation due to the mixing of the compression component and the tensile component, the crystal plane of the cubic phase is {001} plane, {113} plane , {111}, and {133} planes.

Here, it is shown in Fig. 6 that only the crystal faces of these specific orientations are distributed, but this is for the following reasons. Since the copper determines the face-centered cubic structure, the X-ray diffraction measurement by the 2? /? Method shows that the h, k, and l in the {hkl} plane are all odd or not diffracted peaks Do not. If h, k, and l are mixed in an odd number and an even number, the diffraction peak disappears due to the extinction side and measurement can not be performed. Therefore, in describing the constitution of the rolled copper foil according to the above-mentioned embodiments and the like, it is defined as the diffraction of {001} plane ({002} plane), {113} plane, {111} plane and { . From the results of the above-described examples and the like, the effect of the present construction is obvious, and therefore it can be said that it is sufficient to consider the above-described crystal plane.

(Control by the degree of processing)

From the above, assuming that compressive stress> tensile stress, adjusting the ratio of the compressive component to the tensile component changes the path of rotation toward the {022} plane. Specifically, as the compression component becomes larger, the {002} plane or the {113} plane easily passes, and the larger the tensile component becomes, the more easily the {111} plane or the {133} plane is passed. The reason why the crystal face of the main diffraction pattern is the {002} plane, the {113} plane, the {111} plane and the {133} plane is that the crystal plane which can not be entirely rotated by the {022} plane remains in the copper material. It is possible to adjust the ratio of the crystal planes of the respective sub-planes remaining in the copper material by adjusting the compression component and the tensile component in the copper material.

Specifically, the compression component and the tensile component can be controlled by changing the rolling conditions per pass during rolling. Concretely, as attempted in the above-described embodiments and examples, for example, it is possible to pay attention to a change in processing degree per one pass.

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 becomes large. Therefore, the rotation path of the crystal becomes the {002} plane or the {113} plane and rotates toward the {022} plane.

On the other hand, compressive stress > tensile stress is referred to as a premise and the tensile component is increased to thin the copper material, thereby increasing the degree of processing. By increasing the tensile component, the rotation path of the crystal becomes the {111} plane or the {133} plane and rotates toward the plane {022}. On the {133} plane remaining in the copper material after the rolling, the crystal grains of the crystal grains of the crystal grains obtained by the rotation of the crystals due to the tensile component and the crystals once reaching the {022} It can be thought that it includes one. Also, the change in the degree of processing due to the tensile stress is small as compared with the case where the compressive load is increased. That is, the contribution to the degree of processing is larger in the compressive stress.

(Control by Surface Roughness of Rolling Roll)

Here, the surface roughness of the rolling roll also affects the balance of compressive stress and tensile stress. For example, if the surface roughness of the rolled roll is reduced, the area of contact between the rolled roll and the copper material to be rolled increases, and the pressure applied to the contacted face increases. This means that the load on the copper material from the rolling roll is increased, and the copper material becomes difficult to escape from the gap between the rolling rolls. Accordingly, the rolling stress is applied to the copper material in the predominant state because the compressive stress is greater than the compressive stress> tensile stress. Therefore, in this case, the crystal is rotated to the {022} plane through the {002} plane or the {113} plane.

On the other hand, if the surface roughness of the rolling roll becomes large, for example, the contact area between the rolling roll and the copper material is reduced, and the pressure applied to the contact surface is reduced. This means that the load on the copper material from the rolling roll is reduced, and the copper material is easy to escape from the gap between the rolling rolls. Accordingly, the rolling is performed in a state in which the tensile stress is increased on the premise that the stress applied to the copper material is compressive stress> tensile stress. Therefore, in this case, the crystal rotates to the {022} plane through the {111} plane or the {133} plane.

(Other control factors)

In the above embodiments and examples, the crystal rotation is controlled by the degree of processing per pass or the surface roughness of the rolling roll, but the control factor of crystal rotation is not limited to these. That is, to the degree of processing per pass or the surface roughness of the rolled roll, or alternatively, other control factors may be used. As long as any control factor is used, the compressive stress and the tensile stress can be controlled. In fact, a plurality of control methods can be conceived for determining rotation in how to select control factors.

In addition, the control factors affecting the crystal rotation of the rolled copper foil are related to the constitution of the rolling mill, and the specific conditions and numerical values of the respective control factors are largely dependent on the specification of the rolling mill. Concretely, there is a method in which a compressive stress is applied to a copper material due to differences in roll configuration such as the number of rolls, the total number of rolls, the combination of rolls, the diameter and the material of each roll, the surface condition A difference occurs. That is, when the rolling mill is different, since the absolute value of each control factor related to the conditions of the above embodiment is changed, it can be appropriately adjusted for each rolling mill. Also in the same rolling mill, when the surface state of the rolling roll or the material of the rolling roll is different, the absolute value of each control factor becomes different. Therefore, even the same rolling mill can be appropriately adjusted according to each state.

(2) About bendability

(Imparting bending resistance by controlling surface roughness)

As described above, the bending resistance of the rolled copper foil is imparted by suppressing the surface roughness of the rolled copper foil to a predetermined value or less. As a factor controlling the surface roughness of the rolled copper foil, the viscosity η of the rolling oil, the rotating speed U0 of the rolling roll, the speed U1 of the copper material during rolling, the pulling angle α, the average rolling pressure p, (Arithmetic average roughness Ra). Among these factors, various factors other than the arithmetic average roughness Ra of the rolling roll are the oil film equivalent td corresponding to the thickness of the oil film, and the following equations (C) and You can organize them together.

td = {? (U0 + U1)} /? p ... (C)

Technical Paper No. 2: "Adhesive Film Thickness during Rolling and Surface Roughness of Rolls and Materials", Journal of the Japanese Society of Mechanical Engineers, Vol. 44, No. 377, January 1978, p332 -339

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

Here, the rotation speed U0 of the rolling roll, the speed U1 of the copper material at the time of rolling, and the average rolling pressure p in relation to the above formula (C) are also control factors for controlling the degree of processing and neutral point per pass of the rolling condition. In order to control the degree of processing or the neutral point per pass, in order to keep the film equivalent td constant when the control factor is changed, for example, the following methods are available. That is, for example, when the viscosity η of the rolling oil is constantly controlled in the range of 3 × 10 ^-3 N / m ² · s to 5 × 10 ^-3 N / m ² · s, the inlet angle α is constant. Therefore, the film equivalent td can be controlled to be constant. If the oil film equivalent td can be controlled to be constant, the surface roughness of the rolled copper foil can be controlled variously by changing the arithmetic average roughness Ra of the rolling roll.

The surface roughness of the rolled copper foil for improving the bending resistance may be controlled by using other control factors.

(Supplementary explanation of surface roughness)

In the present specification, the surface roughness of the rolled copper foil and the surface roughness of the rolling roll are determined on the basis of different specifications by 10 point average roughness and arithmetic mean roughness Ra, respectively. The use of these surface roughnesses will be described below.

The 10-point average roughness and the arithmetic mean roughness Ra are all numerical values of the degree of surface roughness according to the JIS standard. There are several other regulations that numerically calculate the surface roughness according to the JIS standard. Depending on the degree of surface roughness, the respective numerical values may be greatly different, and it is necessary to distinguish which rule is used according to the individual situation or purpose.

For example, when the difference between the most convex portion and the most concave portion is significant, it is preferable to use the maximum height Rz (JIS B 0601: 2001). The 10-point average roughness used in the specification of the surface roughness of the rolled copper foil is a numerical value obtained by extracting a difference of 5 points each including such a convex portion and a concave portion. That is, in order to quantify the total of 10 points of the top and the valley, information on the degree of irregularities on the average as well as one irregularity difference such as the maximum height Rz is obtained.

Considering that the rolled copper foil deforms in the direction of opening the concave portion when bent and breaks from this portion, in order to specify the surface roughness of the rolled copper foil for the purpose of improving the bending resistance, It is important. It is also possible to more accurately grasp the bending resistance of the rolled copper foil by looking at the average value of several irregularities using a 10-point average roughness, rather than seeing a local irregularity difference.

On the other hand, the arithmetic average roughness Ra used for specifying the surface roughness of the rolling roll is different from the 10-point average roughness or the like, which focuses on the unevenness difference. That is, with respect to the centerline straight line average line, it is possible to see how far the roughness curve is deviated, and the area between the mean line, which is the average of all, and the roughness of the roughness curve.

The rolling roll that defines the surface roughness is an important tool for the deformation processing of the copper material used in the final cold rolling step (S40). Therefore, it is important to grasp the entire state of the rolling roll as far as possible. Therefore, the overall surface roughness of the rolled roll can be grasped by using the arithmetic mean roughness Ra obtained from the surface or the line rather than grasping the difference between the irregularities.

10 Sliding bending test equipment
11 Sample fixing plate
12 Screw
13 vibration transmission portion
14 oscillation drive body
20 spacers
F sample piece

Claims (5)

(Final cold rolling step) having a main surface (main surface) and having a plurality of crystal planes (crystal planes) parallel to the main surface, and after the recrystallization annealing step (annealing step) (Rolled copper foil)
Wherein the plurality of crystal planes include {022} plane, {002} plane, {113} plane, {111} plane and {133}
The diffraction peak intensity ratios (diffraction peak intensity ratios) of the respective crystal planes obtained by X-ray diffraction measurement (X-ray diffraction measurement) using the 2? /? Method on the main surface so as to have a total value of 100 were defined as I {022 }, I {002}, I {113}, I {111} and I {133}
I {022} + I {002} > 75,
The standard diffraction peaks of the respective crystal planes described on the JCPDS card or the ICDD card concerning powder copper having {002} plane, {113} plane, {111} plane, and {133} peak, the diffraction peak intensity of the {113} plane, the {111} plane, and the {133} plane among the diffraction peak intensity ratios of the respective crystal planes calculated from the relative intensity of the { The ratio is I0 {113}, I0 {111} and I0 {133}
(Half widths) of the diffraction peaks of the {113} plane, the {111} plane and the {133} plane obtained from the X-ray diffraction measurement on the main surface are FWHM {113}, FWHM {111 } And FWHM {133}
(I {113} / I0 {113}) X FWHM {113}] + [(I {111} / I0 {111}) X FWHM {111}] + X FWHM {133}] ≤ 1.5,
The surface roughness according to the ten-point average roughness (ten-point average roughness) of the main surface was 10 μm,
By weight.
The method of claim 1,
Characterized in that the main component is copper oxides specified in JIS C1020 or tough pitch copper specified in JIS C1100.
3. The method according to claim 1 or 2,
Wherein at least one of silver, boron, titanium and tin is added.
4. The method according to any one of claims 1 to 3,
Wherein the thickness of the rolled copper foil is 20 占 퐉 or less by the final cold rolling step in which the total degree of processing is 90% or more.
The method according to any one of claims 1 to 4,
Wherein the copper foil is for a flexible printed wiring board.

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