KR20130098937A - Rolled copper foil - Google Patents

Abstract

PURPOSE: A rolled copper foil is provided to have excellent flexibility as well as etching ability and to be desirably utilized for a flexible printed circuit board (FPC). CONSTITUTION: A rolled copper foil contains copper with more than of the mass rate of 99.9%. The rolled copper foil is satisfied with 2.5<=¦d110¦/¦t112¦<=6.0, when a calculated X ray diffraction intensity from {112} side in a rolling surface is appointed as I{112}, and when a calculated X ray diffraction intensity from {110} side is appointed as I{110}. The rolled copper foil contains one or two kinds which amount to 10-300 mass; and are selected from the group composed of Ag, Sn, Mg, In, B, Ti, Zr, Au, and the remainder Cu and other inevitable impurities. [Reference numerals] (AA) Tension; (BB) Desired range; (CC) Amount of an added element (Ag)

Description

Rolled Copper Foil {ROLLED COPPER FOIL}

This invention relates to the rolled copper foil used preferably for FPC (flexible printed circuit board).

As a FPC (flexible printed circuit board), the copper foil composite body which laminate | stacks copper foil and a resin layer is used, The copper foil is required for the etching property at the time of forming a circuit, and the flexibility which considered using FPC.

By the way, FPC is generally used in the state which copper foil recrystallized. The rolling process of copper foil turns a crystal | crystallization, the rolling aggregate structure is formed, and it is said that {112} <112> called copper orientation becomes the rolling aggregate structure of pure copper. And when heat is applied in the process until it anneals after rolling, or rolls up to a final product, ie, it turns into FPC, it recrystallizes. The recrystallized structure after becoming this rolled copper foil is simply called "recrystallized structure" below, and the rolled structure before heat is added is simply called "rolled structure". In addition, the recrystallization structure is largely influenced by the rolling structure, and the recrystallization structure can also be controlled by controlling the rolling structure.

In such a point, the technique which develops the Cube orientation of {001} <100> after recrystallization of a rolled copper foil, and improves flexibility is proposed (for example, patent document 1, 2).

Japanese Patent Publication No. 3856616 Japanese Patent Publication No. 4716520

However, when the Cube orientation of copper foil develops too much, there exists a problem that etching property falls. This is considered to be due to the fact that even if the cube aggregate structure is developed, it is not a single crystal but is in a mixed state in which small grains of different orientations exist among the large grains of the cube orientation, and the etching rate is changed by the particles of each orientation. In particular, as the L / S width of the circuit becomes narrower (fine pitch), the etching property becomes a problem. Moreover, when Cube orientation develops too much, copper foil may become too flexible, and handling property may be inferior.

In addition, in order to adjust the degree of development of the cube orientation, there is a method of controlling the rolling structure after recrystallization in the final rolling, but there is a problem in that the degree of development of the cube orientation cannot be sufficiently adjusted because the cube orientation is not developed or is excessively developed. .

Therefore, the objective of this invention is providing the rolled copper foil which is excellent in both etching property and bendability.

MEANS TO SOLVE THE PROBLEM In the rolling surface in the rolling structure, the more the ratio which the {110} surface exists than the ratio in which the {112} surface exists, the more the roll aggregate structure of copper foil is developed and Cuhe orientation at the time of recrystallization annealing. Found out that it developed. Thereby, in order to adjust the development degree of the cube orientation which improves flexibility, but reduces etching property, it controls the ratio which the {112} plane and {110} plane develop in the rolling surface of copper foil, and etching of rolled copper foil Successfully improved both performance and flexibility.

That is, the rolled copper foil of this invention contains 99.9% or more of copper by mass ratio, makes the calculated X-ray diffraction intensity | strength from the {112} plane in a rolled surface the I {112}, When the calculated X-ray diffraction intensity is set to I {110}, 2.5≤I {110} / I {112} ≤6.0 is satisfied.

The rolled copper foil of this invention contains 10-300 mass ppm of 1 type, or 2 or more types selected from the group of Ag, Sn, Mg, In, B, Ti, Zr, and Au in total, and remainder Cu and an unavoidable impurity It is preferable that it consists of.

It is preferable that the rolled copper foil of this invention contains 2-50 mass ppm of oxygen.

It is preferable that the rolled copper foil of this invention satisfy | fills I {112} <= 1.0 in a rolling surface after 30 minutes of heating at 200 degreeC.

The rolled copper foil of this invention makes the X-ray diffraction intensity of the {200} plane of the rolled surface of the said rolled copper foil the I {200} after 1 second heating at 350 degreeC, and is the {200} plane of a pure copper powder sample. When the X-ray diffraction intensity of is set to I _o {200}, it is preferable to satisfy 5.0 ≦ I {200} / I _o {200} ≦ 27.0, and 13.0 ≦ I {200} / I _o {200} ≦ 27.0 It is desirable to satisfy.

It is preferable that the rolled copper foil of this invention is 4-70 micrometers in thickness.

According to this invention, it is excellent in both etching property and flexibility, and the rolled copper foil which can be used suitably for FPC (flexible printed circuit board) etc. can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically the relationship between the tension applied to copper foil and the amount of Ag in copper foil in final recrystallization annealing for increasing the {112} plane in the rolling surface of copper foil.
2 is a view showing optical microscope images of etching surfaces of Example 5 and Comparative Example 2, respectively.
It is a figure which shows the evaluation correspondence of a reference image and an etching property.

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

<Composition>

It contains 99.9% or more of copper by mass ratio of rolled copper foil. As such a composition, oxygen-free copper standardized by JIS-H3510 (C1011) or JIS-H3100 (C1020), or tough pitch copper standardized by JIS-H3100 (C1100) is mentioned. Moreover, it is preferable to make oxygen content of a rolled copper foil into 2-50 mass ppm. When oxygen content in a rolled copper foil is 2-50 mass ppm, there is hardly a cuprous oxide in rolled copper foil. Therefore, when the rolled copper foil is bent, since there is almost no accumulation of deformation caused by cuprous oxide, cracks are hardly generated and the bendability is improved. In addition, the upper limit of the oxygen content contained in copper is although it does not specifically limit, Generally, it is 500 mass ppm or less, More generally, it is 320 mass ppm or less.

Moreover, you may contain 10-300 mass ppm in total of 1 type, or 2 or more types chosen from the group of Ag, Sn, Mg, In, B, Ti, Zr, and Au. When these elements are added, since there exists a tendency for the {110} plane to increase in a rolling surface, it becomes easy to adjust the value of I {110} / I {112} mentioned later. When the total amount of the above elements is less than 10 mass ppm, the effect of developing the {110} plane on the rolled surface is less. When the total amount of the element exceeds 300 mass ppm, the conductivity decreases and the recrystallization temperature increases, and the copper foil in the annealing after the final rolling It may be difficult to recrystallize while suppressing surface oxidation.

<Thickness>

It is preferable that it is 4-100 micrometers, and, as for the thickness of copper foil, it is more preferable that it is 5-70 micrometers. When thickness is less than 4 micrometers, the handling property of copper foil may be inferior, and when thickness exceeds 100 micrometers, the flexibility of copper foil may be inferior.

<{112} plane and {110} plane of copper foil rolled plane>

Existing intensity | strength of each surface in the copper foil rolled surface computed from the X-ray diffraction intensity of the {200}, {220}, and {111} plane is defined as computed X-ray diffraction intensity. And when the calculated X-ray diffraction intensity of the {112} plane is set to I {112} and the calculated X-ray diffraction intensity from the {110} plane is set to I {110}, 2.5≤I {110} / I {112 } ≤6.0 is satisfied. More preferable copper foil is 4.0≤I {110} / I {112} ≤5.6.

In addition, since X-ray diffraction has a long wavelength, diffraction intensities of {200}, {220} and {111} planes of copper foil can be measured, but diffraction of {422} plane (ie, {112} plane) No peak is obtained. Therefore, from the X-ray diffraction results of {200}, {220}, and {111} by the positive point measurement method, the calculated X-ray diffraction intensities of the {110} plane and {112} plane are obtained using the geometric relationship of the crystal orientation. . In addition, although the diffraction intensity of the {110} plane may be measured directly as being equivalent to the diffraction intensity of the {220} plane, in the present invention, the calculated X calculated from the diffraction intensities of the {200}, {220} and {111} planes. Apply line diffraction intensity.

Specifically, the values of the calculated X-ray diffraction intensities of the {110} plane and the {112} plane were obtained as follows.

First, the positive electrode viscosity of the {200}, {220}, and {111} planes of copper foil is measured. The positive electrode viscosity measuring method is a method of measuring X-ray diffraction while attaching a biaxial (α, β) rotating mechanism to a goniometer for setting a sample and changing these angles. And from the X-ray diffraction positive electrode measurement result (positive viscosity of {200}, {220}, and {111} planes of copper foil), the set degree of {110} plane and {112} plane is calculated using a geometric relationship. You can get it by This calculation can be performed by converting into a reverse pole representation using commercially available software (for example, Standard ODF (manufactured by Norm Engineering Co., Ltd.).

The {110} plane and the {112} plane of the aggregation degree first measure the positive electrode points of the {200}, {220}, and {111} planes, and then make the same to the {200} of the pure copper powder standard sample. , The positive electrode points on the {220} and {111} planes were measured. And the aggregation degree of the {200}, {220}, and {111} planes is normalized with the aggregation degree of the {200}, {220}, and {111} planes of a pure copper powder standard sample, respectively. Then, from the positive electrode viscosity of the {200}, {220}, and {111} planes normalized in this way, the set point of the {110} plane and {112} plane by converting to the reverse pole point by the software (calculated X-ray diffraction intensity ) Is calculated.

The rolled copper foil of this invention can be manufactured by hot rolling and annealing normally, repeating cold rolling and annealing several times (usually about twice), and then carrying out final cold rolling after final recrystallization annealing.

Here, "final recrystallization annealing" means the last thing in the annealing before final cold rolling. Moreover, in order to distinguish the recrystallization structure after final recrystallization annealing from the above-mentioned "recrystallization structure" (recrystallization structure after rolling copper foil), it is called "intermediate recrystallization structure." First, a method of simply adjusting the intermediate recrystallized structure includes changing the annealing temperature. However, simply, `` When the final recrystallization annealing temperature is increased, recrystallized grains of random orientation grow, and when the recrystallized grains become mixed (the width of the size distribution of the grain size becomes large), the cause of surface defects such as streaks after the final rolling is caused. Difficult to control the value of I {110} / I {112} properly

On the other hand, when the tension applied to the copper foil in the final recrystallization annealing is increased, this tension becomes a driving force, and the grain size in the intermediate recrystallized structure becomes large, and many {112} planes, which are rolled surfaces, can exist. However, when the tension is too high, since the {110} plane is reduced in the rolled surface after the final rolling, the tension range may be adjusted so that the value of I {110} / I {112} falls within the above range. In addition, since the value of tension changes also with the final recrystallization annealing temperature and the quantity of the above-mentioned addition element, what is necessary is just to adjust a value of tension accordingly. In addition, tension is tension | tensile_strength between each roll of the entrance side and exit side of a final recrystallization annealing atmosphere when the copper strip is charged in the atmosphere which performs final recrystallization annealing. Since the appropriate value (absolute value) of the tension is changed by the annealing temperature and the components of the copper strip, it is preferable to manage the dimensionless value obtained by dividing the tension by the strength of the material at the annealing temperature.

In addition, conventionally, the value of the tension in a continuous annealing furnace is normally limited to the range of 0.1-0.15 for the purpose of prevention of deterioration of a conveyance roll.

1 shows an example of adjusting the tension applied to the copper foil by final recrystallization annealing to increase the {112} plane to the rolled surface of the copper foil. As described above, when the tension is increased, the {112} plane increases on the rolled surface. However, when the amount of additional elements (such as Ag, etc.) increases, the {110} plane increases on the rolled surface, thus increasing the tension. If not, the ratio of the {112} plane to the rolled plane does not increase. Therefore, the area | region enclosed by the two lines of FIG. 1 becomes a preferable range.

After heating a rolled copper foil for 30 minutes at 200 degreeC, it is preferable to satisfy | fill I {112} / I {100} <= 1.0 in a rolling surface. The heating for 30 minutes at 200 degreeC simulates the heating conditions of copper foil at the time of manufacturing FPC by what is called a cast method. And if the copper foil is completely recrystallized by this heating and the unrecrystallized area | region does not remain, it will be I {112} <= 1.0. In the case of I {112} / I {100}> 1.0, unrecrystallization may remain and the flexibility of the FPC may be inferior.

In the rolled copper foil after one second heating at 350 ℃, 5.0≤I {200} / I o {200} is preferred if any of the ≤27.0. If the {001} <100> orientation (Cube orientation) is developed after recrystallization, good flexibility is obtained, so that if I {200} / _IO {200}, the flexibility may be lowered. 5.0> I {200} / I _o {200}, the flexibility may be lowered. In _{particular, 13.0≤I {200} / I o} {200} ≤27.0 is more preferably no greater. Further, in balance with the other _{properties, I [200] / I o} {200}> to realize a 27.0 to 27.0 was the upper limit because it is difficult to industrially.

[Example]

<Manufacture of Rolled Copper Foil>

An ingot having a thickness of 100 mm was cast as a raw material using tough pitch copper or oxygen-free copper to which an element of the composition shown in Table 1 was used, and hot rolling was carried out at 800 ° C or more to a thickness of 10 mm, and the surface oxidation scale was faced. . Thereafter, cold rolling and annealing were repeated to obtain a rolled coil of 0.5 mm thickness. After the last cold rolling, the copper strip was mailed to a continuous annealing furnace at 700 ° C. and under the tensions shown in Table 1 to effect final recrystallization annealing. In addition, the value of the tension was normalized by dividing the proof strength under the recrystallization annealing temperature of the sample ([Tension force (N / mm ² ) / load strength under the recrystallization annealing temperature (N / mm ² )]). Moreover, the heating time of the copper strip in recrystallization annealing was 100-200 second. Finally, it finished to the thickness of Table 1 by final cold rolling. The rolling workability in final cold rolling was 86 to 99%.

In addition, "Ag 190 ppm OFC" of the composition column of Table 1 shows 190 mass ppm Ag in oxygen-free copper 0FC of JIS-H3510 (C1011) (Example 10) or JIS-H3100 (C1020) (other than Example 10). It means addition. Moreover, "Ag 190 ppm TPC" means that 190 mass ppm Ag was added to tough pitch copper (TPC) of JIS-H3100 (C1100). The same applies to other amounts of addition.

<Crystal orientation>

Regarding the surface (rolled surface) of the copper foil after the final cold rolling, the positive electrode points of {200}, {220}, and {111} surfaces were measured using an X-ray diffractometer (RINT-2500: Rigaku Electric Co., Ltd.) ( X-ray reflection average intensity). From the obtained measurement result, it converted to the reverse pole using Standard ODF (norm engineering company make), and computed the calculated X-ray-diffraction intensity of the {110} plane and the {112} plane.

The measurement conditions of X-ray diffraction were: incident X-ray source: Cu, acceleration voltage: 30 mA, tube current: 100 mA, scattering slit: 0.5 mm, scattering slit: 4 mm, light receiving slit: 4 mm, divergence vertical limiting slit: 12 It set to mm. Moreover, after normalizing the aggregation degree of {200}, {220}, and {111} planes using the value (X-ray reflection average intensity) of the pure copper powder which X-ray diffraction performed on each surface on the same conditions, Converted to pole. Pure copper powder used fine powder copper (325 mesh).

<Grain size>

The grain size of the copper foil immediately after the final recrystallization annealing (before the final cold rolling) was measured for the rolled surface according to the cutting method of JIS-H0501.

<I {200} / I _o {200}>

The X-ray diffraction intensity of the {200} plane was measured with respect to the surface after the copper foil after final cold rolling, respectively, after annealing at 200 degreeC for 0.5 hour, and after 1 second annealing at 350 degreeC. And it was normalized by using a value of a pure copper powder subjected to X-ray diffraction under the same conditions (I _o {200} "X-ray reflection intensity average).

The measurement conditions of X-ray diffraction were incident X-ray source: Cu, acceleration voltage: 25 mA, tube current: 20 mA, scattering slit: 1 mm, scattering slit: 1 mm, light receiving slit: 0.3 mm, diverging longitudinal limiting slit: 10 mm. And monochrome light receiving slit 0.8 mm. Pure copper powder used fine powder copper (325 mesh).

<Flexibility>

First, a thermoplastic polyimide adhesive was coated on a thermosetting polyimide film having a thickness of 12.5 μm and dried. Next, after laminating | stacking the copper foil after final cold rolling on each surface of this film, respectively, it thermocompression-bonded and produced both surfaces CCL. About this double-sided CCL, after forming the circuit pattern which the width | variety of a line / space is 100 micrometers / 100 micrometers, respectively, by the copper foil of both sides, the coverlay film of thickness 25micrometer was coat | covered and processed by FPC. .

A slide bend test was performed on this FPC phosphor to evaluate the bendability. Specifically, using a sliding tester (Type TK-107, Applied Technology Research Institute, Ltd.), the slide radius r (mm) is r = 4 mm for Example 9, and r = for other examples and comparative examples. The FPC was bent at a slide speed of 120 times / minute in 0.72 mm.

The number of bends when the pleated resistance of the copper foil circuit increased by 10% compared to before the test was evaluated as less than 150,000 times, evaluated as being 100,000 to less than 150,000 times, and 15 to 300,000 times. It was set as evaluation (circle) and the thing which exceeded 300,000 times was made evaluation (◎). Flexibility is favorable if it is ◎-△.

<Etchability>

Said double-sided CCL was immersed for 1 minute in the etching liquid (20 mass% solution of ADEKA company make: product name: Tech CL-8 made from ADEKA Corporation) for 30 minutes, and the etching surface was imaged, and the etching surface was image | photographed with the optical microscope.

Since the dark part shows the area | region where the etching is uniform among the said images, etching property evaluated by comparing the picked-up image with the reference image. In FIG. 3, evaluation correspondence of a reference image and etching property is shown. As the area ratio of the dark portion is higher, the etching property becomes better, and ◎ becomes the most excellent etching property. If etching property is (circle)-(triangle | delta), it can be said that etching property is favorable.

The obtained results are shown in Table 1 and Table 2.

As is clear from Table 1 and Table 2, in the case of each Example satisfying 2.5≤I {110} / I {112} ≤6.0, the etching and bendability of the rolled copper foil were excellent.

In addition, when Examples 1 and 2 having the same thickness and final recrystallization annealing conditions were compared, Example 1 having a large amount of Ag was increased in the {110} orientation, and the value of I {110} / I {112} was also increased. It can be seen that the increase. In addition, 13.0> I {200} / I {200} _o For the embodiments 20 to 23, but the bending is slightly reduced compared to other embodiments, practically no problem.

On the other hand, in Comparative Examples 1 and 4 in which the tension of the final recrystallization annealing was lowered compared to Example 6 in which the composition of the copper foil was the same, the {112} orientation was decreased, and the value of I {110} / I {112} was decreased. Etchability was degraded in excess of 6.0.

In the case of Comparative Example 2 in which the composition of copper foil increased the tension at the final recrystallization annealing compared to Example 5, and in the case of Comparative Example 3 in which the composition of copper foil increased the tension at the final recrystallization annealing compared to Example 7 In all cases, the {110} orientation was decreased, and the value of I {110} / I {112} was less than 2.5, resulting in deterioration of the flexibility.

In the case of Example 1, 6 in which a manufacturing method is the same, Example 1 with a low oxygen concentration of copper foil is excellent in flexibility.

2 (a) and 2 (b) are optical microscope images of the etching surfaces of Example 5 and Comparative Example 1, respectively. In Example 5 excellent in etching property, it turns out that there are many ratios of a dark part.

Claims (6)

As a rolled copper foil containing 99.9% or more of copper by mass ratio,
When the calculated X-ray diffraction intensity from the {112} plane on the rolled surface is set to I {112} and the calculated X-ray diffraction intensity from the {110} plane is set to I {110},
Rolled copper foil which satisfies 2.5≤I {110} / I {112} ≤6.0. The method of claim 1,
Rolled copper foil which contains 10-300 mass ppm in total of 1 type, or 2 or more types chosen from the group of Ag, Sn, Mg, In, B, Ti, Zr, and Au, and remainder Cu and an unavoidable impurity. 3. The method according to claim 1 or 2,
Rolled copper foil containing 2-50 mass ppm of oxygen. 3. The method according to claim 1 or 2,
The rolled copper foil which satisfy | fills I {112} <= 1.0 in a rolling surface after 30 minutes of heating at 200 degreeC. 3. The method according to claim 1 or 2,
After 1 second heating at 350 ° C., the X-ray diffraction intensity of the {200} plane of the rolled surface of the rolled copper foil was set to I {200}, and the X-ray diffraction intensity of the {200} plane of the pure copper powder sample was defined as I. _{With 0} {200}
Rolled copper foil which satisfies 5.0≤I {200} / I ₀ {200} ≤27.0. 3. The method according to claim 1 or 2,
Rolled copper foil whose thickness is 4-70 micrometers.

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