KR20130020834A - Rolled copper foil - Google Patents

Abstract

(Problem) The surface of copper foil is moderately roughened to improve handleability, provide excellent rollability, and provide a rolled copper foil having good surface etching characteristics.
(Solution means) Rolling in the state that 60 degree glossiness (G60 _RD ) according to JIS-Z 8741 of the surface measured in the rolling parallel direction is 100 or more and 300 or less, and it heats at 200 degreeC for 30 minutes, and is refined to recrystallized structure. The intensity (I) of the (200) plane determined by the X-ray diffraction of the plane is I / I ₀ ≥ 50 and relative to the intensity (I ₀ ) of the (200) plane obtained by the X-ray diffraction of fine powder copper, The average value of the difference between the maximum height and the minimum height in the thickness direction of each straight line corresponding to the maximum depth of the oil pit, on three straight lines having a length of 175 μm in the rolling parallel direction on the surface and spaced at least 50 μm in the rolling right direction respectively. And the glossiness (G60 _RD ) of the surface measured in the rolling parallel direction and the ratio d / t of the thickness t of the said copper foil is 0.1 or less, and the 60 degree glossiness (G60 _TD ) of the surface measured in the rolling right direction. It is a rolled copper foil whose ratio (G60 _RD / G60 _TD ) is less than 0.8.

Description

Rolled Copper Foil {ROLLED COPPER FOIL}

The present invention relates to a rolled copper foil which is preferably used for FPC where flexibility is required.

High flexibility is required for copper foil used for bending FPC (flexible printed circuit board). As a method for imparting flexibility to the copper foil, a technique for increasing the degree of orientation of the crystal orientation of the copper foil 200 plane (Patent Document 1), a technique for increasing the ratio of crystal grains penetrating in the plate thickness direction of the copper foil (Patent Document 2), and copper foil The technique (patent document 3) which reduces surface roughness Ry (maximum height) corresponding to the depth of an oil pit to 2.0 micrometers or less is known.

A general FPC manufacturing process is as follows. First, copper foil is bonded with a resin film. There exists a method of imidating by adding heat processing to the varnish apply | coated on copper foil, and the method of laminating | stacking the resin film with an adhesive agent and copper foil. The copper foil with the resin film bonded by these processes is called CCL (copper laminated board). Copper foil is recrystallized by the heat processing in this CCL manufacturing process.

By the way, when manufacturing FPC using copper foil, when the copper foil surface is etched in order to improve adhesiveness with a coverlay film, the surface may have the dent (decay down) of about 10 micrometers in diameter. This cause is considered to be caused by the presence of crystal grains with different crystal orientations alone in a uniform structure, if the crystal orientation is controlled to the (200) plane so that the cube structure develops after recrystallization annealing. And since etching speed differs according to the crystal surface to be etched, this single crystal grain is etched deeper than the surroundings, and it becomes recessed. This dent causes a decrease in the etching property of the circuit, or it is determined to be defective in appearance inspection, which causes a decrease in the yield.

As a method of reducing such a dent, the technique of recrystallizing after giving a deformation | transformation which becomes a process-deterioration layer by performing mechanical polishing on the surface of copper foil before rolling or after rolling is reported. According to this technique, non-uniform crystal grains are clustered on the surface after recrystallization by the processing altered layer, so that crystal grains having different crystal orientations do not exist alone.

Japanese Patent Publication No. 3009383 Japanese Unexamined Patent Publication No. 2006-117977 Japanese Unexamined Patent Publication No. 2001-058203 Japanese Unexamined Patent Publication No. 2009-280855

However, in the case of the technique described in Patent Literature 4, there are many nonuniform crystal grains, and since the crystals on the surface of the copper foil are not oriented on the (200) plane, there is a problem that the flexibility is lowered.

On the other hand, in order to ensure the adhesiveness with the roll at the time of copper foil manufacture, or to facilitate the handling of copper foil products, the roughness of the copper foil is roughened by increasing the roll roughness in the final cold rolling. It turned out that the crystal orientation of the copper foil surface falls, and it is inferior to flexibility, or a desiccation occurs.

That is, this invention is made | formed in order to solve the said subject, Comprising: It aims at providing the rolled copper foil with favorable surface etching characteristic, while being excellent in roughness by improving the handleability by roughening a copper foil surface moderately.

MEANS TO SOLVE THE PROBLEM As a result of various examination, the present inventors shear | shear the final copper foil by roughening the surface of copper foil in the last pass of final cold rolling, without making the surface of copper foil too rough immediately before the final pass of final cold rolling. The deformation band was reduced, the flexibility was improved, and the desiccant was found to be less.

In order to achieve the above object, the rolled copper foil of the present invention has a 60 degree glossiness (G60 _RD ) according to JIS-Z 8741 of the surface measured in the rolling parallel direction of 100 or more and 300 or less, and heated at 200 ° C. for 30 minutes. In the state of refining the recrystallized structure, the strength (I) of the (200) plane obtained by X-ray diffraction of the rolled surface is _{equal to} the intensity (I ₀ ) of the (200) plane obtained by X-ray diffraction of fine powder copper. The thickness of each straight line corresponding to the maximum depth of the oil pit on three straight lines I / I ₀ ≥ 50, length 175 μm in the rolling parallel direction on the copper foil surface, and spaced at least 50 μm in the rolling right direction, respectively. The average value d of the maximum height and minimum height difference of the direction, the ratio d / t of the thickness t of the said copper foil is 0.1 or less, and 60 degree glossiness (G60 _RD ) of the surface measured in the rolling parallel direction, and in the rolling right angle direction 60 degree light according to JIS-Z 8741 of measured surface It is also less than the 0.8 ratio _(RD G60 / G60 _TD) of (G60 _TD).

In the case where the above-described copper foil surface after heat treatment at 200 ° C. for 30 minutes is observed by EBSD after electropolishing, the area ratio of crystal grains having an angle difference from the [100] orientation of 15 degrees or more is preferably 20% or less.

After the hot rolling of the ingot, the cold rolling and annealing are repeated, and finally the final cold rolling is carried out, and in the final cold rolling process, the rolling is measured in the rolling parallel direction at the stage before one pass of the final pass. It is preferable that the 60 degree glossiness (G60 _RD ) of one surface exceeds 300.

ADVANTAGE OF THE INVENTION According to this invention, a rolled copper foil with favorable surface etching characteristic is obtained, while being able to roughen a copper foil surface moderately, to improve handleability, and to be excellent in bendability.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the relationship of the roughness of the copper foil surface, and a shear deformation zone.
2 is a diagram illustrating a relationship between oil pits and glossiness.
3 is a diagram showing a method for measuring an average value d corresponding to the maximum depth of an oil pit.
4 is a view showing an optical microscope image of Example 1. FIG.
5 is a view showing an optical microscope image of Comparative Example 3.
6 is a diagram illustrating EBSD measurement results of Example 1. FIG.
7 is a diagram illustrating an EBSD measurement result of Comparative Example 1. FIG.
It is a figure which shows the method of measuring a bending fatigue life with a bending test apparatus.

Hereinafter, the rolled copper foil which concerns on embodiment of this invention is demonstrated. In addition, in this invention,% shall show the mass% unless there is particular notice.

First, with reference to FIG. 1, the technical idea of this invention is demonstrated. When the roughness of the copper foil is increased by increasing the roll roughness in the final cold rolling, the handleability of the copper foil is improved, but the flexibility is lowered or the decimation is more likely to occur (the conventional example 1 in FIG. 1). It is considered that this is because the shear deformation zone occurs in the thickness direction of the copper foil due to the rough roll in the final cold rolling, and further the rolling deformation continues to develop the shear deformation zone.

On the other hand, the method of raising glossiness (surface roughness) is known conventionally in order to acquire the flexibility of copper foil. It is thought that this is because the shear deformation zone does not easily occur in the thickness direction of the copper foil by final cold rolling with a low roughness roll. However, when the glossiness of the copper foil is increased (when the surface roughness is reduced), the handleability of the copper foil is lowered (the conventional example 2 of FIG. 1).

On the other hand, the present inventors do not make the surface of the copper foil too rough (for example, by rolling with a low roughness roll) immediately before the final pass of the final cold rolling, but by roughening the surface of the copper foil in the final pass of the final cold rolling ( For example, it was found that the shear deformation zone was reduced, the bendability was improved, and the desiccant was reduced while the surface of the final copper foil was roughened by rolling with a rough roll) (the invention example in FIG. 1).

That is, although the orientation of conventional copper foil was thought to simply depend on the roughness of the surface of copper foil, it turned out that the magnitude | size of the shear deformation zone inside a material actually affects orientation degree (and desiccation). And in final cold rolling, if the development of a shear zone can fully be suppressed in the pass before a last pass, even if it finishes roughly a copper foil surface in a last pass, high orientation can be obtained.

By the way, the development degree of said shear zone cannot be grasped clearly only by the value of the glossiness conventionally used. That is, as shown in the "invention example" of FIG. 1, if the shear deformation zone is reduced while roughening the surface of the final copper foil, the oil pit is shallow and somewhat wide, and the frequency of occurrence of the oil pit is reduced. Although it is considered (see FIG. 2 (a)), this does not appear well in the glossiness of the rolling parallel direction RD perpendicular to the direction of the oil pit. On the other hand, in the direction perpendicular to the rolling direction (TD), since the oil pit has a certain width, it is easy to grasp the change in the shape and frequency of the oil pit in the parallel direction.

The relationship between such oil pits and glossiness will be described with reference to FIG. 2. (A), (b), (c) of FIG. 2 respond | correspond to the copper foil surface of the "invention example", "conventional example 1", and "conventional example 2" of FIG. 1, respectively.

First, in the "inventive example" of FIG. 2A, when glossiness G _RD is measured along the rolling parallel direction RD, the direction of reflected light changes in an oil pit, and glossiness is not detected. Lowers. On the other hand, when the glossiness G _TD is measured along the rolling right angle direction TD, it is detected that the direction of the reflected light shifts laterally (in the RD direction) from the oil pit from the point where the oil pit extends along the TD. And glossiness becomes high. In short, G _TD is relatively higher than G _RD , and the 60-degree glossiness described later satisfies the relationship of G60 _RD / G60 _TD <0.8.

Next, in the "conventional example 1" of FIG.2 (b), the copper foil surface becomes too rough, and the depth and length (frequency of occurrence) of an oil pit increase, and a rolling parallel direction RD and a rolling right angle direction (TD) Even if the glossiness is measured according to any one of), the direction of the reflected light is not detected by the oil pit, and the glossiness is lowered. In this case, G _TD is relatively lower than G _RD , and the 60 degree glossiness described later is measured, whereby the relationship of G60 _RD / G60 _TD > 1 is satisfied.

On the other hand, in the "conventional example 2" of FIG.2 (c), since the copper foil surface becomes too smooth and oil pit becomes too shallow, even if glossiness G _RD is measured along the rolling parallel direction RD, oil The direction of the reflected light at the pit is hardly changed and the glossiness is increased. That is, since G _RD becomes relatively high compared with G _TD , when 60 degree glossiness mentioned later is measured, the relationship of G60 _RD / G60 _TD becomes close to 1 (in other words, anisotropy of RD and TD becomes small). However, since the copper foil surface is not rough like the "conventional example 1", it becomes G60 _RD / G60 _TD <1.

Next, the specification and composition of the rolled copper foil of the present invention will be described.

(1) Glossiness (G60 _RD )

The 60 degree glossiness (G60 _RD ) of the surface measured in the rolling parallel direction (RD) is 100 or more and 300 or less. When G60 _RD exceeds 300, the copper foil surface becomes too smooth, adhesiveness with the roll at the time of copper foil manufacture falls, or there exists a difficulty in handling of copper foil products. On the other hand, when G60 _RD is less than 100, the surface of the copper foil becomes too rough, the shear deformation zone develops inside the material, the crystal orientation of the surface of the copper foil is lowered, the flexibility is inferior, or the desiccation is good.

(2) G60 _RD / G60 _TD

As described above, the shear deformation zone is reduced while roughening the surface of the final copper foil by roughening the surface of the copper foil in the final pass of the final cold rolling, without roughening the surface of the copper foil just before the final pass of the final cold rolling. The bendability is improved, and the desiccant is reduced. And it was clear by the experiments of the present inventors (Example mentioned later) that the surface with few such shear deformation zones becomes G60 _RD / G60 _TD <0.8. Therefore, the ratio (G60 _RD / G60 _TD ) of 60 ° glossiness (G60 _RD ) of the surface measured in the rolling parallel direction and 60 ° glossiness (G60 _TD ) of the surface measured in the rolling perpendicular direction is prescribed to be less than 0.8. do. In addition, a ratio is adopted in order to cancel the influence of total glossiness.

When G60 _RD / G60 _TD ≥ 0.8, the surface of the copper foil becomes excessively smooth as shown in FIG. 2 (b) above, the adhesiveness with the roll at the time of copper foil manufacture falls, or there exists a difficulty in handling of copper foil products. In addition, when G60 _RD / G60 _TD > 1 as shown in FIG. 2 (c), the surface of the copper foil becomes excessively rough, the shear deformation zone develops, the flexibility decreases, or the desiccant is easily generated.

In addition, as a method of G60 _RD / G60 _TD <0.8, in the final cold rolling as described above, roughness in the pass before the final pass of the final cold rolling, that is, suppresses the development of the shear stage in the pass before the final pass. What is necessary is just to roll using the roll whose surface roughness Ra is comparatively small (for example, 0.05 micrometer or less). On the other hand, in the final pass of final cold rolling, you may roll using the comparatively large roll whose roughness (surface roughness Ra is 0.06 micrometer or more), and what is necessary is just to roughen the copper foil surface finally obtained.

Here, in final cold rolling, if the glossiness (G60 _RD ) of the surface measured in the rolling parallel direction in the step before one pass of the final pass exceeds 300, the copper foil surface is in the pass before the final pass of the final cold rolling. It is preferable because it becomes relatively smooth and the shear deformation zone is hardly introduced.

(3) d / t

When the thickness t of copper foil becomes thin, even if it is the same surface roughness, since the ratio of the surface unevenness to copper foil thickness becomes large, evaluation of the copper foil surface based on said G60 _RD / G60 _TD may not fully be performed. Therefore, in this invention, by specifying d / t <= 0.1, the surface of copper foil can be evaluated regardless of the thickness of copper foil.

As shown in FIG. 3, d is a length of 175 μm in the rolling parallel direction RD on the copper foil surface, and is further formed on three straight lines L ₁ to L ₃ spaced apart from each other by 50 μm or more in the rolling right angle direction TD. It is the average value of the difference between the maximum height H _M and the minimum height H _{S in} the thickness direction of each straight line L ₁ to L ₃ corresponding to the maximum depth of the oil pit. Specifically, the maximum height H _M and the minimum height H _S are measured by measuring the profile in the thickness direction of the L ₁ to L ₃ phases by contact roughness, and di of each straight line L ₁ to L ₃ is calculated. Average it.

Although the thickness of copper foil (or copper alloy foil) is not specifically limited, For example, what is 5-50 micrometers can be used preferably.

(4) I / I ₀

In the state of heating at 200 ° C. for 30 minutes and refining to a recrystallized structure, the strength (I) of the (200) plane obtained by X-ray diffraction of the rolled surface was obtained from the (200) plane obtained by X-ray diffraction of fine powder copper. For the intensity I ₀ , I / I ₀ ≧ 50 is defined. Thereby, the orientation degree of the (200) surface excellent in bendability becomes high. When I / I ₀ <50, the flexibility decreases. The annealing for 200 ° C. for 30 minutes simulates the temperature history applied to the copper foil in the CCL manufacturing process.

(5) Defense difference by EBSD

In a state where the copper foil surface is observed by EBSD after electropolishing after heating at 200 ° C. for 30 minutes and refining to a recrystallized structure, the area ratio of crystal grains having an angle difference from the [100] orientation of 15 degrees or more is preferably 20% or less. Do. The annealing for 200 ° C. for 30 minutes simulates the temperature history applied to the copper foil in the CCL manufacturing process. Moreover, you may heat for 30 minutes at 200 degreeC also about the copper foil which already had thermal history and became CCL. Since the structure of the copper foil heat-treated until once recrystallized hardly changes even if it heats further, in the observation by EBSD, it heats at 200 degreeC for 30 minutes, without distinguishing between copper foil which received a heat history and copper foil which is not received. I do it.

When observed with EBSD, if the area ratio is less than 20%, the orientation difference between the crystal grains on the surface of the copper foil is small, and the proportion by which crystal grains with different crystal orientations exist alone in a uniform structure decreases. Desiccation is reduced. In addition, in order to make the said area ratio less than 20% when it observes by EBSD, in the final cold rolling as mentioned above, before the last pass of the last cold rolling which suppresses the development of a shear zone in the pass before a final pass. In the pass of, roughness (surface roughness Ra is 0.05 µm or less) may be rolled using a relatively small roll.

(6) composition

As copper foil, tough pitch copper and oxygen-free copper of 99.9 wt% or more of purity can be used, and a well-known copper alloy can be used according to the intensity | strength and electroconductivity required. Oxygen-free copper is standardized by JIS-H 3510 (alloy number C1011) and JIS-H 3100 (alloy number C1020), and tough pitch copper is standardized by JIS-H 3100 (alloy number C1100).

As a well-known copper alloy, For example, 0.01-0.3 wt% tin-containing copper alloy (more preferably, 0.001-0.02 wt% tin-containing copper alloy); 0.01-0.05 wt% silver containing copper alloy; 0.005 to 0.02 wt% indium-containing copper alloy; 0.005 to 0.02 wt% of chromium-containing copper alloy; Copper alloys containing 0.05 wt% or less in total of one or more selected from the group consisting of tin, silver, indium and chromium, and among them, Cu-0.02 wt% Ag is often used as an excellent electrical conductivity.

Next, an example of the rolled copper foil manufacturing method of this invention is demonstrated. First, after the hot rolling of the ingot which consists of copper and a necessary alloy element, and also an unavoidable impurity, cold rolling and annealing are repeated, and finally it finishes to predetermined thickness by final cold rolling.

Here, as described above, the shear deformation zone is made while roughening the surface of the final copper foil by roughening the surface of the copper foil in the final pass of the final cold rolling, without roughening the surface of the copper foil just before the final pass of the final cold rolling. The lower the amount, the higher the flexibility, and the lower the desiccation. And the surface with few such shear deformation zones will be G60 _RD / G60 _TD <0.8.

Therefore, just before the final pass of the final cold rolling, the surface of the copper foil is rolled using a relatively small roll so that the roughness (surface roughness Ra is, for example, 0.05 µm or less) or 1 in the final cold rolling. What is necessary is just to enlarge the pass workability and to roll. On the other hand, in the final pass of final cold rolling, the roughness (surface roughness Ra is 0.06 micrometer or more) is rolled using a comparatively large roll, or it rolls using the rolling oil with high viscosity, and roughly roughens the copper foil surface obtained finally. do.

In addition, in order to reduce the shear deformation zone while roughening the surface of the final copper foil, in the final two passes of the final cold rolling, or the final pass, rolling is performed using a coarse roll or using a high viscosity rolling oil as described above. Although it is necessary, it is preferable to adjust the rolling conditions in a final pass from the point which is easy to adjust. On the other hand, when roughness of a roll is made rough before the last 3 passes of final cold rolling, a shear deformation zone will develop.

Moreover, what is necessary is just to adjust annealing conditions so that the average particle diameter of the recrystallized grain obtained by annealing just before final cold rolling may be 5-20 micrometers. Moreover, what is necessary is just to make the rolling workability in final cold rolling into 90% or more.

Example

Ingots were cast using tough pitch copper or oxygen-free copper to which elements of the composition shown in Table 1 were used as raw materials, and hot rolling was carried out at 800 ° C or higher to a thickness of 10 mm, and the surface oxide scales were face-treated. Thereafter, cold rolling and annealing were repeated, and finally, final cold rolling was finished to a thickness of 0.012 mm (Examples 1 to 9 and Comparative Examples 1 to 7). However, in Example 10, the finishing thickness was 0.018 mm, and in Example 11, the finishing thickness was 0.006 mm. The rolling workability in final cold rolling was 99.2%.

In addition, the final cold rolling was performed in 10-15 passes, and as shown in Table 1, rolling was performed by changing the surface roughness of the roll until the last pass and the surface roughness of the roll of the final pass. The surface roughness of the rolls from the first pass of the last pass to just before the last pass is the same.

In addition, "0.02% Ag addition TPC" in the composition column of Table 1 means that 0.02 mass% Ag was added to tough pitch copper (TPC) of JIS-H3100 (alloy number C1100). In addition, "0.007% Sn addition OFC" in the composition column of Table 1 means that 0.007 mass% Sn was added to oxygen-free copper (OFC) of JIS-H3100 (alloy number C1020). However, only Example 6 uses oxygen-free copper (OFC) standardized in JIS-H 3510 (alloy number C1011) as oxygen-free copper, and Examples 4, 5, 7, 9, 10, and Comparative Example 7 are oxygen-free copper. Oxygen-free copper (OFC) standardized in JIS-H 3100 (alloy number C1020) was used.

Thus, each characteristic was evaluated about each copper foil sample obtained.

(1) glossiness

The glossiness (G60 _RD , G60 _TD ) of the copper foil surface was measured according to JIS-Z 8741 along the rolling parallel direction (RD) and the rolling right angle direction (TD), respectively.

(2) cube assembly

After heating a sample for 30 minutes at 200 degreeC, the integral value (I) of the (200) surface intensity calculated | required by the X-ray diffraction of the rolled surface was calculated | required. This value was divided by the integral value (I ₀ ) of the (200) surface strength of fine powder copper (325 mesh, used after heating at 300 ° C. for 1 hour in a hydrogen stream), which was measured in advance, and the I / I ₀ value was calculated.

(3) Maximum depth of oil pit (average d)

As shown in FIG. 3, using a contact roughness meter (SE-3400 manufactured by Kosaka Research Institute), the copper foil surface had a length of 175 µm in the rolling parallel direction RD and 50 µm or more in the rolling right angle direction TD, respectively. The difference di between the maximum height H _M and the minimum height H _S on the three straight lines L ₁ to L ₃ to be separated was determined, respectively. By taking the average of the di each straight line (L ₁ ~ L ₃₎ it was set to d. In addition, it was set as d (mm) / t (mm).

(4) Difference in defense by EBSD

EBSD (backscattered electron beam diffractometer, Nihon Denshi Co., Ltd. JXA8500F, acceleration voltage 20 kV, current 2e-8A, measuring range 1000 μm × 1000 μm after electrolytic polishing of sample surface after heating at 200 ° C. for 30 minutes at (2) , Step width 5 μm). The area ratio of crystal grains whose angle difference from the [100] orientation is 15 degrees or more was determined by image analysis. In addition, the number of crystal grain diameters exceeding 20 micrometers was visually counted within the observation range of 1 mm square of a sample surface. And the sample containing this observation range was etched for 2 minutes at normal temperature using the 20% solution of Adecatek CL-8 (made by Adeka Co., Ltd.), and the image which image | photographed the surface after etching with the optical microscope was taken. Light and dark were binarized, and the dark part exceeding 50 micrometers in diameter was counted as the desiccant. In addition, the surface of the copper foil after etching becomes a shape reflecting the crystal orientation, while the structure having the [100] orientation becomes a plane parallel to the surface of the copper foil, whereas the portion having the other crystal orientation generates irregularities due to the crystal orientation. . Thus, the desiccant portion appears dark in the optical microscope.

4 shows the optical microscope image of Example 1, and FIG. 5 shows the optical microscope image of Comparative Example 3. FIG. 6 shows the EBSD measurement result of Example 1, and FIG. 7 shows the EBSD measurement result of Comparative Example 1. FIG. 6 and 7, the gray or black region shows crystal grains whose angle difference from the [100] orientation is 15 degrees or more.

(5) scratches on the surface

The surface of each sample was visually observed, and the case where the flaw which has a length of 10 mm or more in a rolling direction had 5 points / m <^2> or more was made into x.

(6) flexibility

After the sample was heated and recrystallized at 200 ° C. for 30 minutes, the bending fatigue life was measured by the bending test apparatus shown in FIG. 4. This apparatus has a structure in which the vibration transmission member 3 is coupled to the oscillation drive body 4, and the copper foil 1 under test is fixed to the apparatus at a total of four points of the screw 2 portion indicated by the arrow and the distal end portion of the apparatus 3. When the vibration part 3 drives up and down, the intermediate part of the copper foil 1 is bent in a hairpin shape by the predetermined curvature radius r. In this test, the number of times until fracture | rupture when bending was repeated under the following conditions was calculated | required.

In addition, when plate | board thickness is 0.012 mm, test conditions are as follows: Test piece width: 12.7 mm, Test piece length: 200 mm, Test piece collection direction: Sampling so that the longitudinal direction of a test piece may be parallel to a rolling direction, and a radius of curvature r: 2.5 mm, vibration stroke: 25 mm, vibration speed: 1500 times / min. Moreover, when bending fatigue life was 30,000 times or more, it was judged that it has the outstanding flexibility.

In addition, when the sheet thickness was 0.018 mm and 0.006 mm, respectively, the curvature radius r was changed to 4 mm and 1.3 mm so that the bending test and the bending deformation at the plate thickness of 0.012 mm may be the same, but other test conditions The same was done.

The obtained results are shown in Table 1.

As is clear from Table 1, for each invention example in which G60 _RD is 100 or more and 300 or less, I / I ₀ ≥ 50, d / t is 0.1 or less, and G60 _RD / G60 _TD is less than 0.8, [100] according to EBSD [100] ] The area ratio of the crystal grain whose angle difference from an orientation is 15 degrees or more became less than 20%, the number of desiccants was few, and there was no flaw in the copper foil surface, and the flexibility was also excellent.

On the other hand, in the final cold rolling, in the case of Comparative Examples 1, 5, and 7 in which both the surface roughness of the roll up to the last pass and the surface roughness of the roll of the final pass were Ra = 0.05 µm or less, G60 _RD of the copper foil surface was 300. It exceeded and the flaw generate | occur | produced on the copper foil surface, and handleability was inferior. Moreover, in the case of the comparative example 5, since the rolling workability in final cold rolling was made into 96% low, I / I ₀ <50, and even if it raises glossiness, the crystal grain of 15 degrees or more of the angle difference from an [100] orientation is increased. The area ratio exceeded 20% and many desiccations occurred.

In the final cold rolling, in the case of Comparative Example 2 in which the surface roughness of the roll up to just before the final pass was roughened at Ra = 0.06 μm or more, and the surface roughness of the roll of the final pass was made Ra = 0.05 μm or less, the area ratio was 20. The number of desiccants increased more than%. Moreover, G60 _RD of the copper foil surface exceeded 300, the scratch was generate | occur | produced on the copper foil surface, and handling property was inferior.

In the final cold rolling, in the case of Comparative Examples 3, 4, and 6 in which both the surface roughness of the roll up to the last pass and the surface roughness of the roll of the last pass were roughened to Ra = 0.06 µm or more, the area ratio exceeded 20%. The number of desiccants has increased.

In addition, in the case of Comparative Examples 3 and 4, since the roll surface roughness of all the passes of the final cold rolling was roughened, the shear deformation zone developed inside the material, and the crystal orientation of the copper foil surface fell, resulting in I / I ₀ <50. . On the other hand, in the case of the comparative example 6, since the roughness of the roll until the last pass was smoother than the comparative examples 3 and 4, the glossiness and I / I ₀ became higher than the comparative examples 3 and 4, Inhibition became insufficient, and the area ratio exceeded 20%, and the number of desiccants increased. In addition, in order to suppress the shear zone while keeping the roll roughness up to just before the final pass, there are methods such as lowering the plate speed, but in that case, the glossiness exceeds 300, resulting in surface scratches. The judgment is considered to be x.

Claims (3)

X-ray of the rolled surface in a state where the 60 degree glossiness (G60 _RD ) according to JIS-Z 8741 of the surface measured in the rolling parallel direction is 100 or more and 300 or less, and is heated at 200 ° C. for 30 minutes and refined into a recrystallized structure. The intensity (I) of the (200) plane determined by diffraction is I / I ₀ with respect to the intensity (I ₀ ) of the (200) plane determined by X-ray diffraction of fine powder copper. ≥ 50,
The average value of the difference between the maximum height and the minimum height in the thickness direction of each straight line corresponding to the maximum depth of the oil pit on three straight lines that are 175 μm in length in the rolling parallel direction and 50 μm or more apart in the rolling right direction on the copper foil surface. d and the ratio d / t of the thickness t of the copper foil is 0.1 or less,
The ratio of the 60 degree glossiness (G60 _RD ) of the surface measured in the rolling parallel direction and the 60 degree glossiness (G60 _TD ) according to JIS-Z 8741 of the surface measured in the rolling perpendicular direction (G60 _RD / G60 _TD ) Rolled copper foil less than 0.8. The method of claim 1,
The rolled copper foil whose area ratio of the crystal grain whose angle difference from a [100] orientation is 15 degrees or more is observed when the copper foil surface after the said 200 degreeC x 30-minute heat processing is observed by EBSD after electropolishing. 3. The method according to claim 1 or 2,
After the hot rolling of the ingot, the cold rolling and annealing are repeated, and finally, the final cold rolling is carried out, and in the final cold rolling process, 60 of the surfaces measured in the rolling parallel direction in the step before one pass of the final pass. Rolled copper foil with a glossiness (G60 _RD ) exceeding 300.

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