TW201529901A - Electrolytic copper foil, flexible circuit board and battery - Google Patents

Abstract

Provided is an electrolytic copper foil having flexibility and strength appropriate for a circuit board or a battery. The present invention relates to an electrolytic copper foil used for a circuit board or a battery wherein a peak value of nitrogen (N), sulfur (S), or chlorine (Cl) existing at a position of a depth dp[[mu]m] satisfying 0.3x ≥ dp ≥ 0.7x exists in each strength profile of N, S, or Cl shown in secondary ion mass spectrometry (SIMS) measured in the thickness direction from an S surface or an M surface of the electrolytic copper foil of the thickness x[[mu]m]. Preferably, if the strength (number of counts) refers to I(dp), and the strengths deviated by x/8 from the thickness dp representing the peak value refers to I(dp-x/8) and I(dp+x/8), the electrolytic copper foil satisfies I(dp) ≥ 100, I(dp-x/16) ≥ 1.5 x I(dp-x/8), I(dp+x/16) ≥ 1.5 x I(dp+x/8), I(dp) ≥ 1.5 x I(dp-x/8), I(dp) ≥ 1.5 x I(dp+x/8).

Description

Electrolytic copper foil, flexible circuit board and battery

The present invention relates to a copper foil, and more particularly to an electrolytic copper foil which is suitable for use in a circuit board and a battery and which has both flexibility and rigidity.

In various electronic equipments, in order to use a circuit board as a substrate or a connecting material, in general, the conductive layer of the circuit board is copper foil. In addition, copper foil is widely used as a negative electrode material for batteries such as lithium ion batteries.

The above circuit board or battery generally uses a rolled copper foil or an electrolytic copper foil. As a rolled copper foil used for a copper foil for a circuit board or a copper foil for a battery, in order to suppress the crystal growth in the heat history applied during the process, it is necessary to add a metal or the like as an essential component. Therefore, the original conductivity of the copper foil is lowered, and the manufacturing cost is also increased, which is worse than the electrolytic copper foil. Therefore, it is inclined to widely use an electrolytic copper foil which is highly productive and easy to be thinned, and is used as a copper foil for a circuit board or a copper foil for a battery.

In the electrolytic copper foil used in a circuit board or a battery, in order to have mechanical properties suitable for its use, an electrolyte solution containing an organic compound and chlorine is often used to form a foil. The foil is prepared by using an electrolyte solution in which an organic compound and chlorine are added, and the amount of impurities extracted in the crystal is controlled, whereby an electrolytic copper foil having flexibility and rigidity suitable for each use can be produced.

In applications requiring flexibility, it is an electrolytic copper foil which requires a small amount of impurities for crystallization. Therefore, it is attempted to use the above-mentioned organic compound and its decomposition product and chlorine in the copper foil by using a manufacturing method such as using a special organic compound or reducing the addition amount of the organic compound or chlorine.

Further, in the electrolytic copper foil which is required for the use of flexibility, the production method is to prevent the extraction of impurities in the crystal by not adding an organic compound and chlorine, but in this case, since the organic compound cannot be expected The interfacial activity that can be exerted requires the electrolyte to be relatively clean to be as free as possible from impurities such as oil, which in turn leads to poor manufacturing costs.

On the other hand, in applications requiring rigidity, an electrolytic copper foil having a large amount of impurities extracted in the crystal is required. Therefore, a manufacturing method generally employed is to add an organic compound having a specific functional group and having a strong adsorption force, and the organic compound and its decomposition product are extracted into a copper foil with chlorine.

The use of the circuit board is required to be able to withstand the flexibility of bending and stretching of the flexible circuit board, and is required to withstand the expansion and contraction of the battery during the charging and discharging. However, in the past, the electrolytic copper foil was extremely difficult to satisfy the following, that is, to increase the amount of impurities in the crystal in order to make it rigid, and to reduce the amount of impurities in the crystal in order to make it soft. .

Patent Document 1 (Patent No. 4,287,952) discloses an electrolytic copper foil having a small content of impurities due to the use of a specific organic compound. However, the electrolytic copper foil of the invention has good flexibility but is not rigid.

Patent Document 2 (Patent 3850155) discloses an electrolytic copper foil having a low content of impurities due to the use of a clean electrolyte. However, the hair Ming's electrolytic copper foil is also soft, but its rigidity is not good.

Patent Document 3 (JP-A-2009-221592) discloses an electrolytic copper foil having a large content of impurities due to the use of a plurality of nitrogen-containing organic compounds. However, the electrolytic copper foil of the invention has good rigidity but poor flexibility.

Patent Document 4 (Patent 5180815) discloses an electrolytic copper foil which is produced by a current density of a different two or more. However, the object of the invention is to reduce the curvature of the surface and to achieve both flexibility and rigidity.

[First technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 48279952 (JP-A-2010-037654).

[Patent Document 2] Japanese Patent No. 3850155 (JP-A-2000-182623).

[Patent Document 3] Japanese Laid-Open Patent Publication No. 2009-221592.

[Patent Document 4] Japanese Patent No. 5180815 (WO2007/105635).

The present invention provides an electrolytic copper foil which is suitable for use in a circuit board or a battery, and which combines flexibility and rigidity.

The electrolytic copper foil of the present invention preferably has a first plating layer having a relatively large impurity content and having rigidity; and a second plating layer formed on both sides of the first plating layer, having a relatively small impurity content and being soft Sex. The electrolytic copper foil of the present invention is an electrolytic copper foil for a circuit board or a battery, wherein the surface of the S or M surface of the electrolytic copper foil is in the thickness direction, and the primary ion is a cesium ion (Cs+). In the SIMS (Secondary Electron Mass Analysis) intensity curve measured by the condition of the acceleration voltage of 5 kV, the sputtering area of 200 μm × 400 μm, and the analysis area being 9% of the central portion of the sputtering region, When the intensity [count value] in the depth d [μm] is I (d) and the thickness of the electrolytic copper foil is x [μm], 0.3x is satisfied. Dp In the depth dp [μm] of the condition of 0.7x [μm], there are nitrogen (N) measured by secondary (detected) ions (14N63Cu-) or secondary (detected) ions (34S-) The measured sulfur (S) or the peak of nitrogen (N), sulfur (S) or chlorine (Cl) measured by secondary (detected) ions (35Cl-).

Preferably, the intensity I(dp) of the peak is satisfied separately

The conditions.

The electrolytic copper foil of the present invention is an electrolytic copper foil for a circuit board or a battery, wherein SIMS (secondary electron mass analysis) is measured in the thickness direction from the S surface or the M surface of the electrolytic copper foil. In the intensity curve, when the intensity [count value] is I (d) and the thickness of the electrolytic copper foil is x [μm] in the depth d [μm] calculated from the surface, 0.3x is satisfied. Dp In the depth dp [μm] of the condition of 0.7x [μm], there is a peak of nitrogen (N), sulfur (S), or chlorine (Cl), and the peak intensity I(dp) is satisfied separately.

The conditions.

The electrolytic copper foil for a circuit board of the present invention can be applied to a flexible circuit board.

Further, the electrodeposited copper foil for a battery of the present invention can be suitably used for a battery.

The electrolytic copper foil of the present invention can be subjected to various surface treatments for the purpose of improving adhesion, improving rust prevention performance, and improving chemical resistance, as needed.

According to the present invention, it is possible to provide an electrolytic copper foil having a three-layer structure in which a copper layer having a high content of impurities is contained inside a copper layer having a softness of less impurity content, and is suitable for a circuit board. And the use of the battery, and both softness and rigidity.

1 (1A, 1B) ‧‧‧ Copper layer with relatively low impurity content and softness

2‧‧‧Tibet with relatively high impurity content and a rigid copper layer

3 (3A, 3B) ‧ ‧ first anode

4‧‧‧Second anode

5‧‧‧ cathode

6‧‧‧ electrolyte

7‧‧‧electrolytic copper foil

Fig. 1 is a schematic view showing the three-layer structure copper foil of the present invention.

Fig. 2 is an explanatory view showing a cylindrical foil forming apparatus.

Fig. 3 is a schematic view showing a SIMS intensity curve measured in the thickness direction of the three-layer structure copper foil according to the embodiment of the present invention.

Fig. 4 is a view showing an example of a SIMS intensity curve of chlorine in the thickness direction measured by the S surface in the three-layer structure copper foil according to the embodiment of the present invention.

The electrolytic copper foil of the present invention is, for example, as illustrated in Fig. 1, comprising: a copper layer having a relatively low impurity content and possessing flexibility, that is, a central plating layer 2; and being formed on both sides of the layer 2, the impurity content is relatively relatively high. A plurality of rigid copper layers, that is, outer plating layers 1A, 1B.

The electrolytic copper foil of the present invention is formed into a foil by, for example, an electrolytic foil-making apparatus as shown in Fig. 2. The electrolytic foil-making apparatus is composed of a rotating cylindrical cathode 5 (surface made of SUS or titanium), and a first anode 3A, 3B (coated with lead oxide or coated noble metal oxide) arranged concentrically with respect to the cathode 5 a titanium electrode); and a second anode 4 (a titanium electrode coated with lead or a noble metal oxide) disposed on the bottom side by being interposed on the first anodes 3A, 3B independently of the first anodes 3A, 3B , constituted. While the electrolyte 6 is supplied to the foil-making apparatus, a current is caused to flow between the anode and the cathode, and copper of a predetermined thickness is electrolyzed to the surface of the cathode 5, after which the rollers 8A, 8B are rotated, and copper is plated from the surface of the cathode 5. Stripped into a foil.

Further, the copper foil 7 at this stage is referred to as an electrolytic copper foil, and the surface in contact with the electrolytic solution 6 of the electrolytic copper foil 7 is referred to as a deposition surface or a matte surface (M surface), and will be in a cylindrical shape. The surface in contact with the cathode 5 is referred to as a glossy surface or a smooth surface (S surface). Although the above description has been made on the foil forming apparatus using the cylindrical cathode 5, there is also an example in which the cathode is formed into a plate shape and the copper foil is produced by the foil forming apparatus.

When the foil is formed into an electrolytic copper foil 7 by the apparatus shown in Fig. 2, a copper sulfate plating solution is used as the electrolytic solution 6. The sulfuric acid concentration of the copper sulfate plating solution is 20 to 150 g/L (liter), and particularly preferably 30 to 120 g/L. When the sulfuric acid concentration is less than 20 g/L, since it is difficult to flow between the anode and the cathode, the actual operation is quite difficult, and the uniformity and electrical adhesion of the plating are also deteriorated. On the other hand, when the sulfuric acid concentration exceeds 150 g/L, since the solubility of copper is lowered, a sufficient copper concentration cannot be obtained, so that the actual operation is quite difficult. In addition, it also causes corrosion of equipment such as electrolytic foil-making devices.

The copper concentration is 40 to 150 g/L, and particularly preferably 60 to 120 g/L. When the copper concentration is less than 40 g/L, it is difficult to ensure a practically operable current density in the production of an electrolytic copper foil. When the copper concentration is raised to be higher than 150 g/L, a relatively high temperature is required, which is practically not feasible.

In order to impart the flexibility and rigidity necessary for the use of the electrolytic copper foil of the present invention, an organic compound and chlorine are added to the copper sulfate plating solution. An organic compound added to a copper sulfate electroplating bath, which is composed of an organic compound which is generally defined as a brightener or an accelerator, and is generally defined as a homogeneous agent or a smoothing agent. An organic compound; generally a polymeric organic compound defined as a polymer or inhibitor. Each of the organic compounds can be appropriately combined and used in accordance with the properties required for rigidity and flexibility in accordance with surface smoothness and the like.

Specifically, when surface smoothness is required, three configurations of a brightener, a homogenizer, and a polymer are often used, or two of a brightener, a homogenizer, and a polymer are used. In addition, especially when surface smoothing is not required In the case of the nature, it is mostly composed of a homogenizing agent and a polymer, or it is composed of only one of a homogenizing agent and a polymer.

The chlorine added in the copper sulfate plating bath is mainly used as a catalyst to promote the adsorption of the additive.

The concentration of the organic compound to be added to the copper sulfate plating bath is not particularly limited, and may be appropriately adjusted so as to avoid the occurrence of an abnormality such as smoothness, glossiness, or an abnormal phenomenon such as scorching or abnormal precipitation. When the softness is emphasized, the amount of the organic compound (impurity content) is slightly reduced, and when the rigidity is emphasized, the amount of the organic compound (impurity content) is preferably slightly increased.

The chlorine concentration is 0 to 100 ppm, particularly preferably 20 to 50 ppm. Although the characteristics of the present invention can be obtained at 0 ppm, there is no adsorption effect of the additive due to chlorine, so a large amount of additives must be charged. Further, when the content is more than 100 ppm, there is no particular effect, and conversely, corrosion of equipment such as an electrolytic foil-making apparatus is promoted, which is not preferable.

The temperature of the electrolytic bath is 25 to 80 ° C, particularly preferably 30 to 70 ° C. When the bath temperature is less than 25 ° C, it is difficult to secure a sufficient copper concentration and current density in the production of the electrolytic copper foil, and thus it is practically impossible. In addition, if the temperature is higher than 80 ° C, there will be difficulties in the operation of the work and on the equipment, which is practically impossible.

The above-mentioned electrolysis conditions can be appropriately adjusted from the respective ranges without causing problems such as copper deposition or electroplating.

Since the surface roughness of the S surface immediately after the production of the electrolytic copper foil transfers the surface roughness of the cathode 5, in the case where surface smoothness is required, It is preferable to reduce the surface roughness of the cathode 5. However, the surface roughness of the cathode 5 is set such that the surface roughness Rz of the S surface of the electrolytic copper foil is less than 0.1 μm, and it is judged from the current polishing technique or the like that the required smoothness is achieved. It is quite difficult and is not suitable for mass production.

Further, the thickness of the S surface can be adjusted by the roughening treatment of the post-engineering, so that it is possible to roughen the surface roughness of the cathode 5 without risking that the copper foil may peel off from the cathode 5, and therefore, it is not necessary to The thickness Rz of the S surface of the foil-formed copper foil is 5.0 μm or more.

The thickness Rz of the M surface of the electrolytic copper foil can be controlled by a combination of various organic compounds so that the surface has glossiness or the like. Various organic compounds are appropriately combined and adjusted according to the use.

Further, the thickness of the electrolytic copper foil is preferably from 3 μm to 210 μm. Copper foil with a thickness of less than 3 μm is less practical due to stricter manufacturing conditions in terms of processing technology and the like. From the current state of use of the copper foil, the upper limit of the thickness is about 210 μm. An electrolytic copper foil having a thickness of 210 μm or more is difficult to use as a copper foil for a circuit board or a battery, and the cost advantage of using an electrolytic copper foil is also lost.

In the first anode 3 (3A, 3B), the current density is 20 to 200 A/dm ² , particularly preferably 30 to 120 A/dm ² . When the current density of the first anode 3 is less than 20 A/dm ² , the production efficiency is considerably low in the production of the electrolytic copper foil, and thus it is impractical. Further, if it is increased to more than 200 A/dm ² , a relatively high copper concentration, high temperature, and high flow rate are required, which imposes a large burden on the electrolytic copper foil manufacturing apparatus, which is impractical.

In the present embodiment, two types of anodes of the first anodes 3A and 3B and the second anode 4 are used. Although the mechanism is not known, the layer that has been plated near the second anode 4 at the bottom is a layer that has been plated near the first anode 3 of the upper portion, containing more organic compounds, decomposition products thereof, and chlorine as impurities. And analyze them as nitrogen (N) or sulfur (S), or chlorine (Cl). Therefore, as shown in FIG. 2, when the second anode 4 is disposed to be sandwiched between the first anodes 3A, 3B, a copper foil having a three-layer structure as schematically shown in FIG. 1 is obtained, that is, electroplated on the second anode. The copper layer having a relatively large amount of the above-mentioned impurities in the vicinity of 4 is a copper layer which is interposed between the first impurities 3 and has a relatively small amount of the impurities. 1 is a view schematically showing a layer 1A plated in the vicinity of the first anode 3A, a center plating layer 2 plated in the vicinity of the second anode 4, and a layer 1B plated in the vicinity of the first anode 3B.

The copper foil of the above three-layer structure is not limited to a three-layer structure, and the thickness ratio of the central plating layer 2 is also important. When the central plating layer 2 is relatively thin, rigidity is insufficient, and when the central plating layer 2 is relatively thick, the flexibility is insufficient. The ratio is the total anode (the length of the first anode 3 (3A, 3B) with the current density of the second anode 4 and the current density of the first anode 3 (3A, 3B) and the length of the second anode 4 It is determined in proportion to the length of the total length of the second anode 4).

In the second anode 4, the ratio of the current density is preferably from 10 to 80% of the first anode 3 (3A, 3B), and the ratio thereof is particularly preferably from 30 to 60%. When the ratio of the current density of the second anode 4 is less than 10% of the first anode 3, in order to ensure the ratio of the central plating layer 2, the ratio of the overall length of the anode to the length of the second anode 4 must be greatly increased, and as a result Said that it will cause the overall current density The sharp drop in production and low productivity have prevented this situation from being better. Further, when the ratio is higher than 80%, the difference in the amount of impurity extraction between the layer 1 and the layer 2 described above is reduced, and the characteristics required by the present invention cannot be obtained.

When the ratio of the total length of the anode to the length of the second anode 4 is L4 [%], the current density of the first anode 3 (3A, 3B) is set to CD3, and the current density of the second anode 4 is set to CD4. It is preferable to satisfy the range disclosed by the following formula 1.

In the above formula 1, if L4 is less than 5, since the outer plating layers 1A, 1B are formed to be relatively thick, the rigidity is insufficient. If L4 is greater than 20, the central plating layer 2 will be relatively thick, thereby causing Insufficient softness.

In the copper foil of the present embodiment, the intensity (count value) of nitrogen (N), sulfur (S), or chlorine (Cl) peaks in the SIMS intensity curve measured in the thickness direction from the S surface or the M surface. It is the center plating layer 2 existing in the vicinity of the center part of the thickness direction. In a copper foil of thickness x μm, the central plating layer 2 exists to satisfy 0.3x Dp A depth dp [μm] of 0.7 x [μm] is preferred.

As described above, in order to obtain the characteristics required by the present invention, the thickness ratio of the central plating layer 2 is quite important, and it is necessary to make the thickness of the central plating layer 2 not too thin, even if the peak shape of the peak of the SIMS intensity curve is not too sharp, It is necessary to make the thickness of the central plating layer 2 not too thick, even if the peak of the peak of the SIMS intensity curve is not too flat.

Specifically, the intensity I of two places separated by a predetermined distance from the aforementioned dp is set as an index. The thickness of the so-called central coating 2 is not too thin, it means The intensity I of the position indicated by (dp±x/16) is used as an index, and the so-called not too thick means the intensity I of the position indicated by (dp±x/8) as an index.

In the SIMS of the present embodiment, the intensity I (dp) of the peak is satisfied as follows.

In the case of the condition, the thickness of the central plating layer 2 will not be too thin, so it is preferable, and if it is satisfied

In the case of the condition, the thickness of the central plating layer 2 is not excessively thick, and moreover, it is preferable that the difference in the amount of impurities extracted from the outer plating layers 1A, 1B and the central plating layer 2 is made clear. In addition, if it is satisfied

In the case of the conditions, the difference in the amount of impurities extracted from the outer plating layers 1A, 1B and the central plating layer 2 will be more clear, and therefore it is preferable.

Here, in the SIMS of the present embodiment, if the intensity (count value) of a certain value or more is not equal to the noise, it is difficult to distinguish the noise. Therefore, the [count value] of the intensity I (dp) of the peak is 100 or more. good. When I(dp) is 100 or more, it is necessary to satisfy the above formula of 1.5 × I (dp ± x / 8) to be 67 or more, and it is necessary to satisfy the requirement that 3.5 × I (dp ± x / 8) is 29 or more. Sufficient to distinguish from noise.

The above description of the three-layer structure copper foil according to the embodiment of the present invention illustrated in Fig. 1 will be described with reference to the SIMS intensity curve measured in the thickness direction in the schematic view shown in Fig. 3.

First, the intensity (count) of the nitrogen (N), or sulfur (S), or chlorine (Cl) peak I (dp) exists in the 0.3x Dp The depth dp [μm] of 0.7x [μm]. Next, the intensity I (dp-x/16) existing at a position shifted by -x/16 [μm] in the thickness direction by dp [μm] is formed to be shifted by dp [μm] -x/ The intensity I (dp-x/8) present at the position of 8 [μm] is 1.5 times or more. Similarly, the intensity I (dp+x/16) existing at a position shifted by +x/16 [μm] in the thickness direction by dp [μm] is formed to be also shifted by dp [μm] + x The intensity I (dp+x/8) present at the position of /8 [μm] is 1.5 times or more. Further, I(dp) is formed to be 1.5 times or more (more preferably 3.5 times or more) of I(dp-x/8) and I(dp+x/8).

In the three-layer structure copper foil according to the embodiment of the present invention illustrated in Fig. 1, an example of a SIMS intensity curve in which chlorine in the thickness direction is measured from the S surface is disclosed in Fig. 4 . The copper foil with a thickness of 16 μm satisfies 4.8 Dp 11.2 [μm] The depth dp=7.5 [μm] from the S surface, the intensity (count value) of chlorine (Cl) is the "analysis point A" indicating the peak value of 3540, and the peak intensity I can be understood. (7.5) To satisfy I(7.5)=3540>100 I(6.5)=998>1.5×I(5.5)=1.5×500≒750 I(8.5)=654>1.5×I(9.5)=1.5×303≒ 455 I(7.5)=3540>3.5×I(5.5)=3.5×500≒1750 I(7.5)=3540>3.5×I(9.5)=3.5×303≒1061

The conditions.

In addition, although in the SIMS intensity curve of FIG. 4, there is a region having a high impurity content near the surface, this is a phenomenon in which it is practically unavoidable to detect the impurity of the surface of the copper foil attached to the vicinity of the analysis. As for the impact on the copper layer.

In this example, although the measurement was performed on the S surface, the same result was obtained from the M surface measurement.

In applications requiring flexibility as described above, an electrolytic copper foil having a low impurity content is required. Further, in applications requiring rigidity, an electrolytic copper foil having a large amount of impurities is required.

On the other hand, the three-layer structure electrolytic copper foil of the present embodiment illustrated in Fig. 1 is configured to have a relatively flexible copper layer (external plating layers 1A and 1B), and the content of impurities is relatively small. The surface layer portion having the largest amount of deformation at the time of bending and stretching; and the relatively rigid copper layer (the center plating layer 2) have a relatively large content of impurities, and are located near the center portion of the load concentration. With such a configuration, it is possible to provide an electrolytic copper foil which is resistant to repeated bending and stretching in a flexible circuit board as a circuit board, and which is resistant to charge and discharge as a battery. The rigidity of the expansion and contraction is repeated.

As disclosed in FIG. 2, the second anode 4 is not necessarily disposed at the center of the entire length of the first anode 3 (3A, 3B). When the deformation on the M-face side is maximized, the second anode 4 may be disposed on the side of the squeezing electrolyte 6 (the left side in FIG. 2) on the surface of the rotating cylindrical cathode 5. Thereby, the copper layer having a relatively large impurity content is disposed closer to the S surface side at the center portion, and the copper layer having a relatively smaller impurity content on the M surface side is thicker. It also enhances the softness of the deformation. Similarly, when the deformation on the S-face side is maximized, the second anode 4 can be disposed on the surface of the cylindrical cathode 5 close to the rotation away from the electrolyte 6 side. (right side in Figure 2)

Thus, the position of the layer 2 is moved from the center portion to the S surface side or the M surface side in accordance with the position of the second anode 4. Therefore, in the present specification, the position of the center plating layer 2 is defined as the vicinity of the center portion.

Further, although an electrolytic copper foil having a three-layer structure is disclosed in FIG. 2, it is of course possible to produce an electrolytic copper foil having a four-layer structure or more, and the current density is changed in more stages.

In addition, the copper foil used for the circuit board and the battery is used, and in the manufacturing process, although the heat treatment is performed at 150 to 350 ° C, even if the heat treatment is performed, the electrolytic copper of the present invention is maintained as illustrated in FIG. 1 . The three-layer construction of the foil. More specifically, even if the heat treatment is performed, the structure is maintained, that is, the outer plating layer 1 in the vicinity of the surface portion has a copper layer having a relatively small impurity content; and the central plating layer 2 in the vicinity of the central portion has an impurity content. Relatively many copper layers.

It is also assumed that there is a manufacturing method which is the same three-layer structure as that of the present invention, and is constituted by an apparatus, an electrolytic solution, and an additive which are different in each layer. However, in comparison with the single device, the electrolyte, and the additive composition of the present invention, it is easy to predict that the manufacturing cost and the yield thereof will be greatly deteriorated, and in addition, in the thinner foil-forming process, particularly in the first The processing capability of one layer will be expected to be quite difficult, so it is impractical.

Hereinafter, the copper foil according to the three-layer structure of the present invention will be described in detail with respect to the examples, but the present invention is not limited thereto.

(1) foil production

Examples 1 to 9 and Comparative Examples 1 to 8

Table 1 discloses the manufacturing conditions of the electrolyte composition and the like. The copper sulfate plating solution having the composition shown in Table 1 was subjected to a clean treatment by an activated carbon filter, and similarly, the additives shown in Table 1 were added to form a specified concentration.

The first anode 3 and the second anode 4 shown in FIG. 2 were adjusted to have a current density and an anode length as shown in Table 2. Similarly, a rotary cylinder type foil forming apparatus shown in FIG. 2 was used to manufacture a thickness of 12 μm. Electrolytic copper foil.

Comparative Example 9

Comparative Example 9 is a reproduction experiment of Example 3 described in Patent Document 4. In order to reproduce, the copper sulfate plating solution composed in Example 3 was prepared. MPS-Na, DDAC polymer (unisense: FPA100L, manufactured by SENKA Co., Ltd.) and chloric acid were added as additives, and the concentration was specified. The electrolysis conditions were set such that the current density of the first-stage electrolysis was 74 A/dm ² and the current density of the second-stage electrolysis was 52 A/dm ² , and an electrolytic copper foil having a thickness of 12 μm was produced by a rotary-cylinder foil-making apparatus.

MPS: 3-mercapto-1-propanesulfonic acid

PEG: polyethylene glycol (average molecular weight: 6000)

The electrolytic copper foil of each of the examples and the comparative examples was divided into three samples (samples 1 to 3). Sample 1 was used in SIMS analysis, sample 2 was used in the softness evaluation experiment, and sample 3 was used in the stiffness evaluation experiment.

The contents of each analysis and experiment are detailed below.

(1) SIMS analysis

Using Sample 1, SIMS (Secondary Ion Mass Spectrometer) analysis was performed.

The analysis device and analysis conditions are as follows.

Analytical device

Physical Electronics company: "PHI 6650"

Analysis condition

Primary ion: Cs+ (5kV, 100nA)

Secondary (detected) ion

Nitrogen (N): 14N63Cu ^-

Sulfur (S): 34S ^-

Chlorine (Cl): 35Cl ^-

Sputtering surface: S surface

Sputtering area: 200μm × 400μm

(gate area (analysis area): 9% of the center of the sputtering area)

Sputtering time: until the M surface is penetrated

In addition, since the thickness x is 12 μm, 0.3x Dp 0.7x [μm] formation

The judgment in the SIMS analysis is that the SIMS intensity curve in the thickness direction is determined by the S surface, which satisfies 3.6. Dp In the depth dp [μm] of 8.4 [μm], there is a peak of nitrogen (N), sulfur (S), or chlorine (Cl), and the intensity I (dp) of the peak is satisfied.

The sample of the condition is marked as ○ (qualified) and will be satisfied separately

The sample of the condition was marked as ◎ (excellent), and the other samples were evaluated as marked × (failed). The results are shown in Table 3.

(2) Softness evaluation test Using sample 2, in a heat treatment operation in which a load is applied in a manufacturing process for general flexible circuit board in a nitrogen atmosphere, the heat treatment corresponding to 300 ° C × 1 hour is performed, and the growth is cut. A test piece of 130 mm × 15 mm was subjected to an MIT bending test until the copper foil was broken according to the following conditions. In this experiment, a bending test was performed by applying a load which did not cause the sample to have a degree of deflection, thereby performing softness evaluation.

Bending radius R: 0.38mm

Bending angle: ±135°

Bending speed: 175 times / min

Load: 10g

Samples that have not been broken for more than 800 bends are marked as ○ (qualified), especially samples that have not been broken more than 1000 times are marked as ◎ (excellent), and samples that are broken at 800 times Then, the evaluation mark is × (failed), and the result is shown in Table 4.

(3) Rigid evaluation experiment

Using Sample 3, a heat treatment at 150 ° C for 1 hour, which is equivalent to a heat treatment operation in a general battery application, was carried out in a nitrogen atmosphere, and then cut into test pieces having a length of 130 mm × 15 mm, according to the following conditions. The MIT bending test was performed until the copper foil was broken. In this experiment, a heavy load was applied to the sample to perform a bending test, thereby performing rigidity evaluation.

Bending radius R: 0.80mm

Bending angle: ±135°

Bending speed: 175 times / min

Load: 500g

Samples that have not been broken by bending more than 300 times are marked as ○ (qualified), especially those samples that have not been broken more than 400 times are marked as ◎ (excellent), and samples that are broken after 300 times Then, the evaluation mark is × (failed), and the result is shown in Table 4.

Examples 1 to 9 can be clearly seen from Table 3, and the SIMS intensity curve in the thickness direction is measured by the S surface, which satisfies 3.6. Dp In the depth dp [μm] of 8.4 [μm], the peak intensities I(dp) of nitrogen (N), or sulfur (S), or chlorine (Cl) are respectively satisfied.

The conditions. In particular, Embodiments 2, 3, and 6 are respectively satisfied.

The conditions. Accordingly, in the first to ninth embodiments, the layer 2 in which the content of nitrogen (N), sulfur (S), or chlorine (Cl) is shown as a peak in the depth direction is formed so as to A preferred thickness ratio exists in the vicinity of the central portion. As a result, it can be easily observed that Examples 1 to 9 are formed into a copper foil having a three-layer structure, and the structure is such that a relatively rigid copper layer having a relatively large impurity content in the vicinity of the center portion is in a preferable ratio. It is sandwiched between soft copper layers with relatively low impurity content near the surface layer.

Examples 1 to 9 can be clearly seen from Table 4, and they have superior flexibility and rigidity, and in particular, in any of Examples 2, 3, and 6, all are marked as ◎ (excellent). Evaluation results.

Comparative Examples 1 to 8 can be clearly seen from Table 3, and the SIMS intensity curve in the thickness direction is measured by the S surface, which satisfies 3.6. Dp In the depth dp [μm] of 8.4 [μm], although the peak intensity I(dp) of sulfur (S) or chlorine (Cl) is up to I (dp) 100 analysis points, however, they are not satisfied with

The conditions. In Comparative Examples 1 to 8 which exhibited such an analysis result, there was no layer in which the impurity content in the thickness direction exhibited a certain and clear peak in the thickness direction, that is, the layer 2 was not present, or This means that the preferred thickness of the layer 2 described above is not met, so that it can be judged that the comparative example does not form a three-layer structure having an appropriate thickness ratio as in the embodiment.

Therefore, Comparative Examples 1 to 8 can be clearly seen from Table 4, and it is impossible to achieve both flexibility and rigidity.

Comparative Example 9 can also be clearly seen from Table 3, and the SIMS intensity curve in the thickness direction is measured by the S surface, which satisfies 3.6. Dp In the depth dp [μm] of 8.4 [μm], although there is a peak intensity I(dp) of chlorine (Cl) up to I (dp) 100 analysis points, however, they are not satisfied with

The conditions. The analysis result shown in Comparative Example 9 is that I(dp) is higher than I(dp-1.5) and lower than I(dp+1.5), and this result means that the distribution state of the impurity content in the thickness direction is formed as , S side is low, M side is high The oblique distribution, as shown in the examples, can be judged that the copper layer does not form a three-layer structure in the comparative example.

In the production method described in Patent Document 4, which is the basis of Comparative Example 9, regarding the current conditions, only the current density after the first-stage electrolysis is described, and the manufacturing method of the present invention is not reduced, and only the copper is reduced. Electrolytic conditions for the operation of the current density at the center of the foil. According to this, it is possible to determine that the manufacturing method described in Patent Document 4 cannot be formed in a three-layered copper layer having a relatively large impurity content and a relatively large impurity content in the copper layer having a relatively low impurity content and having a relatively high impurity content. structure.

Further, Patent Document 4 is completely different from the characteristics required by the present invention. Further, in Patent Document 4, the description of the impurity content in the copper foil is not mentioned, and therefore, only hypothetical and analogical behaviors are used. It is quite difficult to achieve the content described in the present invention.

According to the present invention, it is possible to provide an electrolytic copper foil which is suitable for use in a circuit board and a battery, and which has both flexibility and rigidity, and which is formed by a three-layer structure in which the content of impurities is relatively small and the flexibility is maintained. Inside the copper layer, there is a rigid copper layer with a relatively high content of impurities.

In addition, the present invention can be made of a special electrolytic copper foil which is originally required to have a plurality of equipments and a three-layer structure, and is composed of a single device, an electrolyte, and an additive, and can also be composed of a single device, an electrolyte, and an additive. Manufactured, thus having superior productivity and stability.

1 (1A, 1B) ‧‧‧ Copper layer with relatively low impurity content and softness

2‧‧‧Tibet with relatively high impurity content and a rigid copper layer

Claims (6)

An electrolytic copper foil comprising: a first plating layer having a relatively high impurity content and holding rigidity; and a second plating layer formed on both sides of the first plating layer, having a relatively low impurity content and possessing flexibility. The electrolytic copper foil according to the first aspect of the invention, wherein the surface of the S or M surface of the electrolytic copper foil is in the thickness direction, and the primary ion is cesium ion (Cs+), the acceleration voltage is 5 kV, and the sputtering is performed. In the SIMS (Secondary Electron Mass Analysis) intensity curve measured by the condition that the emission region is 200 μm × 400 μm and the analysis region is 9% of the central portion of the sputtering region, in the depth d [μm] calculated from the surface, When the intensity [count value] is I (d) and the thickness of the electrolytic copper foil is x [μm], 0.3x is satisfied. Dp In the depth dp [μm] of the condition of 0.7x [μm], there are nitrogen (N) measured by secondary (detected) ions (14N63Cu ^- ) or secondary (detected) ions (34S ^- ) The measured sulfur (S) or the peak of chlorine (Cl) measured by the secondary (detected) ion (35Cl ^- ). The electrolytic copper foil according to claim 2, wherein the intensity I (dp) of the peaks respectively satisfies the following conditions: An electrolytic copper foil used in a circuit board or a battery, characterized in that in the SIMS (Secondary Electron Mass Analysis) intensity curve measured in the thickness direction from the S surface or the M surface of the electrolytic copper foil, In the depth d [μm] of the surface, when the intensity [count value] is I (d) and the thickness of the electrolytic copper foil is x [μm], 0.3x is satisfied. Dp In the depth dp [μm] of the condition of 0.7x [μm], there are peaks of nitrogen (N), sulfur (S), or chlorine (Cl), and the peak intensity I(dp) satisfies the following conditions: A flexible circuit board using the electrolytic copper foil according to any one of claims 1 to 4. A battery using the electrolytic copper foil according to any one of claims 1 to 4.