KR102263024B1 - Electrolytic copper foil, flexible circuit board and battery - Google Patents

Abstract

[Problem] To provide an electrolytic copper foil that has both flexibility and rigidity suitable for use in wiring boards and batteries.
[Solution] As an electrolytic copper foil used for wiring boards or batteries, nitrogen (N) shown in SIMS (secondary ion mass spectrometry) measured from the S-side or M-surface surface of the electrolytic copper foil having a thickness of x [μm] in the thickness direction ) or for each intensity profile of sulfur (S) or chlorine (Cl), nitrogen (N) or sulfur (S) or chlorine ( Cl) has a peak value. Preferably, the intensity [number of counts] is I(dp), and the intensity at a position x/8 away from the depth dp representing the peak value is I(dp-x/8), I(dp+x/8) If you do,
I(dp)≥100
I(dp-x/16)≥1.5×I(dp-x/8)
I(dp+x/16)≥1.5×I(dp+x/8)
I(dp)≥1.5×I(dp-x/8)
I(dp)≥1.5×I(dp+x/8)
It is an electrolytic copper foil that meets each of the

Description

Electrolytic copper foil, flexible wiring board and battery {ELECTROLYTIC COPPER FOIL, FLEXIBLE CIRCUIT BOARD AND BATTERY}

The present invention relates to copper foil, and more particularly, to an electrolytic copper foil having both flexibility and rigidity suitable for use in wiring boards and batteries.

In various electronic devices, a wiring board is used as a board|substrate and connection material, and copper foil is generally used for the conductive layer of a wiring board. Moreover, copper foil is widely used as a negative electrode material also in batteries, such as a lithium ion battery.

A rolled copper foil or an electrolytic copper foil is generally employ|adopted for the said wiring board and a battery.

The rolled copper foil used as the copper foil for wiring boards or the copper foil for batteries adds a metal etc. as an essential component in order to suppress the crystal growth in the heat history applied in the manufacturing process. For this reason, the intrinsic electroconductivity of copper foil is reduced, and manufacturing cost also becomes large, and performance becomes inferior to an electrolytic copper foil. Therefore, as a copper foil for a wiring board or a copper foil for a battery, an electrolytic copper foil with high productivity and easy thinning tends to be widely used.

An electrolytic copper foil employed for a wiring board or a battery is often foil-made by an electrolyte solution to which an organic compound and chlorine are added in order to have mechanical properties suitable for the use. An electrolytic copper foil having flexibility and rigidity suitable for each use can be manufactured by manufacturing the foil with an electrolyte solution to which an organic compound and chlorine are added, and controlling the amount of impurities mixed into the crystal.

For applications requiring flexibility, an electrolytic copper foil with a small amount of impurities mixed into the crystal is required. Therefore, a manufacturing method is employed in which a special organic compound is used or the amount of organic compound or chlorine added is reduced so that the organic compound, its decomposition product, and chlorine are not mixed in the copper foil.

In addition, in the case of electrolytic copper foils for applications requiring flexibility, there is a manufacturing method in which impurities are prevented from entering the crystal by not adding organic compounds and chlorine in the first place, but in this case, the surfactant action exhibited by organic compounds cannot be expected, so oil content A very clean electrolyte solution that does not contain as much impurities as possible is required, which increases the manufacturing cost.

On the other hand, for applications requiring rigidity, an electrolytic copper foil with a large amount of impurities mixed into the crystal is required. For this reason, a manufacturing method is generally employed in which an organic compound having a special functional group and strong adsorption power is added, and the organic compound, its decomposition product, and chlorine are mixed into the copper foil.

For wiring board applications, flexibility to withstand repeated bending and stretching in flexible wiring boards and rigidity to withstand repeated expansion and contraction during charging and discharging are often required for battery applications. However, as described above, it is necessary to increase the amount of impurities mixed into the crystal in order to have rigidity and to reduce the amount of impurities mixed into the crystal to have flexibility. It is extremely difficult to satisfy both properties in the conventional electrolytic copper foil. .

Patent Document 1 (Japanese Patent No. 4827952) discloses an electrolytic copper foil containing little impurities by use of a special organic compound. However, although the electrolytic copper foil of this invention is excellent in flexibility, it is inferior in rigidity.

Patent Document 2 (Japanese Patent No. 3850155) discloses an electrolytic copper foil containing little impurities by using a clean electrolyte solution. However, although the electrolytic copper foil of this invention is also excellent in flexibility, it is inferior in rigidity.

Patent Document 3 (Japanese Patent Application Laid-Open No. 2009-221592) discloses an electrolytic copper foil containing many impurities by use of a plurality of nitrogen-containing organic compounds. However, although the electrolytic copper foil of this invention is excellent in rigidity, it is inferior in flexibility.

Patent Document 4 (Japanese Patent No. 5180815) discloses an electrolytic copper foil characterized in that it is manufactured at different current densities of two or more levels. However, this invention is aimed at lowering the profile of the precipitation surface, and flexibility and rigidity cannot be reconciled.

Japanese Patent No. 4827952 (Japanese Patent Laid-Open No. 2010-037654) Japanese Patent Publication No. 3850155 (Japanese Patent Laid-Open No. 2000-182623) Japanese Patent Laid-Open No. 2009-221592 Japanese Patent No. 5180815 (WO2007/105635)

An object of the present invention is to provide an electrolytic copper foil having both flexibility and rigidity suitable for use in wiring boards and batteries.

Preferably, the electrolytic copper foil of the present invention has a first plating layer having a relatively high impurity content and rigidity, and a second plating layer having a relatively low impurity content and flexibility formed on both sides of the first plating layer. The electrolytic copper foil of the present invention is an electrolytic copper foil used for a wiring board or a battery, wherein the primary ions are cesium ions (Cs ⁺ ), the accelerating voltage is 5 kV, In the SIMS (secondary electron mass spectrometry) intensity profile in which the sputtered region was measured as 200 μm × 400 μm and the analysis region as 9% of the central portion of the sputtered region, the intensity [number of counts] at a depth d [μm] from the surface ] is I(d) and the thickness of the electrolytic copper foil is x [μm], at a depth dp [μm] satisfying 0.3x ≤ dp ≤ 0.7x [μm], secondary (detection) ions (14N63Cu ^- Nitrogen (N) measured as ), or ^{sulfur (S) measured as secondary (detection) ions (34S -} ), or nitrogen (N) or sulfur (S) measured as secondary (detection) ions (35Cl ^{- )} ) or an electrolytic copper foil with a peak of chlorine (Cl).

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

I(dp)≥100

I(dp-x/16)≥1.5×I(dp-x/8)

I(dp+x/16)≥1.5×I(dp+x/8)

I(dp)≥1.5×I(dp-x/8)

I(dp)≥1.5×I(dp+x/8)

It is desirable to satisfy each of

The electrolytic copper foil of the present invention is an electrolytic copper foil used for wiring boards or batteries, and in the SIMS (Secondary Electron Mass Spectrometry) intensity profile measured in the thickness direction from the S surface or M surface surface of the electrodeposited copper foil, from the surface A depth dp[μm] satisfying 0.3x≤dp≤0.7x[μm] when the strength [number of counts] at the depth d[μm] is I(d), and the thickness of the electrolytic copper foil is x[μm]. ], there is a peak of nitrogen (N) or sulfur (S) or chlorine (Cl), and the intensity I (dp) of the peak is

I(dp)≥100

I(dp-x/16)≥1.5×I(dp-x/8)

I(dp+x/16)≥1.5×I(dp+x/8)

I(dp)≥3.5×I(dp-x/8)

I(dp)≥3.5×I(dp+x/8)

It is desirable to satisfy each of

The electrolytic copper foil for wiring boards of the present invention can be suitably used for a flexible wiring board.

Moreover, the electrolytic copper foil for batteries of this invention can be used suitably for a battery.

The electrodeposited copper foil of the present invention can also be subjected to various surface treatments for the purpose of improvement in adhesion, improvement in rust prevention function, improvement in chemical resistance, etc. as necessary.

According to the present invention, an electrolytic copper foil having a three-layer structure in which a copper layer with high impurity content and rigidity exists inside a copper layer with low impurity content and flexibility, and having both flexibility and rigidity suitable for use in wiring boards and batteries. can provide

<Figure 1>
BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram explaining the three-layer structure copper foil of this invention.
<Figure 2>
It is explanatory drawing which shows the drum-type leaf-making apparatus.
<Fig. 3>
It is a schematic diagram of the SIMS intensity profile measured in the thickness direction in the three-layer structure copper foil which is one Embodiment of this invention.
<Fig. 4>
It is an example of the SIMS intensity profile which measured chlorine in the thickness direction from the S surface in the three-layer structure copper foil which is one Embodiment of this invention.

The electrolytic copper foil of the present invention, for example, as illustrated in FIG. 1 , a copper layer having a relatively high impurity content and rigidity, that is, the central plating layer 2 and formed on both sides of the layer 2, to include a copper layer having a low impurity content and flexibility, that is, the outer plating layers 1A and 1B.

The electrolytic copper foil of this invention is manufactured with the electrolytic foil making apparatus as shown in FIG. 2, for example. The electrolytic foil making apparatus comprises a rotating drum-shaped cathode 5 (surface made of SUS or titanium), and first anodes 3A and 3B (lead oxide coated or noble metal oxide) arranged concentrically with respect to the cathode 5. coated titanium electrode), current can be supplied independently of the first anodes 3A, 3B, and the second anode 4 (lead or noble metal oxide) sandwiched between the first anodes 3A and 3B and arranged on the bottom side coated titanium electrode), and while supplying the electrolytic solution 6 to the papermaking apparatus, a current is passed between the anode and the cathode to electrodeposit copper to a predetermined thickness on the surface of the cathode 5, and then the rollers 8A and 8B It is rotated to peel the copper from the surface of the cathode 5 in a foil form.

In addition, the copper foil 7 at this stage is called an electrolytic copper foil, and the surface in contact with the electrolyte 6 of the electrolytic copper foil 7 is the precipitation surface or the mat surface (M surface), the surface in contact with the drum-shaped cathode 5 is called the glossy side or shiny side (S side).

Although the above demonstrated the foil-making apparatus which employ|adopted the drum-shaped cathode 5, copper foil may be manufactured with the foil-making apparatus which makes a plate-shaped cathode.

In order to manufacture the electrolytic copper foil 7 with 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 preferably 20 to 150 g/L (liter), particularly preferably 30 to 120 g/L. When the sulfuric acid concentration is less than 20 g/L, it becomes difficult to flow an electric current between the anode and the cathode, so that realistic operation becomes difficult, and the uniformity and electrodeposition of the plating also deteriorate. When the sulfuric acid concentration exceeds 150 g/L, the solubility of copper decreases, so that a sufficient copper concentration cannot be obtained, and realistic operation becomes difficult. Moreover, corrosion of equipment, such as an electrolytic manufacturing apparatus, is accelerated|stimulated.

The copper concentration is preferably 40 to 150 g/L, particularly preferably 60 to 120 g/L. When the copper concentration is less than 40 g/L, it becomes difficult to secure a current density capable of realistic operation in the production of the electrolytic copper foil. Raising the copper concentration above 150 g/L is impractical as it requires a significant high temperature.

In order to have the flexibility and rigidity required 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.

The organic compound added to the copper sulfate plating solution is generally composed of a sulfur-containing organic compound defined as a brightener or accelerator, a nitrogen-containing organic compound similarly defined as a leveler or leveler, and a high molecular weight organic compound similarly defined as a polymer or inhibitor. Each organic compound is conveniently combined and used according to properties required in addition to rigidity and flexibility, such as surface smoothness.

Specifically, when surface smoothness is required, it is often used with a three-type configuration of a brightener, a leveler, and a polymer, or a two-type configuration of only one of a brightener, a leveler, and a polymer. Moreover, when surface smoothness in particular is not calculated|required, it is used by 2 types of structure of a leveler and a polymer, or 1 type structure of only either one of a leveler and a polymer in many cases.

Chlorine added to the copper sulfate plating solution mainly plays a catalytic function to promote adsorption of additives.

The concentration of the organic compound added to the copper sulfate plating solution is not specifically specified, and it can be conveniently adjusted so that abnormalities such as lack of smoothness and gloss or burning or abnormal precipitation do not occur. ), and when rigidity is emphasized, it is preferable to add a large amount of organic compounds (impurity content).

The chlorine concentration is preferably 0 to 100 ppm, particularly preferably 20 to 50 ppm. Even at 0 ppm, the properties of the present invention are obtained, but since the effect of accelerating the adsorption of the additive by chlorine does not act, it is necessary to add a large amount of the additive. Moreover, there is no particular meaning in making it higher than 100 ppm, and since corrosion of equipment, such as an electrolytic foil manufacturing apparatus, is accelerated|stimulated, it is not preferable.

The electrolytic bath temperature is preferably 25 to 80°C, particularly preferably 30 to 70°C. When the bath temperature is less than 25°C, it becomes difficult to ensure sufficient copper concentration and current density in the production of the electrolytic copper foil, which is not realistic. In addition, raising the temperature higher than 80 ℃ is not realistic because it is very difficult in terms of operation and equipment.

The electrolysis conditions are appropriately adjusted and performed under conditions in which copper precipitation, plating burning, and the like do not occur in each range.

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, when surface smoothness is required, it is preferable to make the surface roughness of the cathode 5 low. However, in making the surface roughness of the cathode 5 such that the surface roughness Rz of the S surface of the electrolytic copper foil is less than 0.1 μm, it is difficult to achieve a smooth finish up to that point in consideration of the current polishing technology, and it is also difficult to mass-produce. I don't think it's right.

In addition, since the roughness of the S surface can be adjusted by a post-process roughening treatment, it is not necessary to roughen the surface of the cathode 5 until the copper foil does not peel off from the cathode 5, There is no meaning in making roughness Rz of the copper foil S surface used into 5.0 micrometers or more.

The roughness Rz of the M surface of the electrolytic copper foil can be controlled, such as giving the surface glossiness by combining each organic compound. It is adjusted by combining each organic compound suitably according to a use.

Moreover, it is preferable that the thickness of an electrolytic copper foil is 3 micrometers - 210 micrometers. This is because copper foil having a thickness of less than 3 μm is not realistic due to strict manufacturing conditions in relation to handling technology and the like. The upper limit of the thickness is about 210 μm in the current use of copper foil. It is difficult to think that an electrodeposited copper foil having a thickness of 210 µm or more is used as a copper foil for a wiring board or a battery, and the cost advantage of using an electrodeposited copper foil is also lost.

The current density in the first anode 3 (3A, 3B) is preferably 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 20A/dm 2} , the production efficiency in the manufacture of the electrolytic copper foil is very low, which is not realistic. In addition, raising more than 200A/dm ² requires a fairly high copper concentration, high temperature, and high flow rate, which is not realistic because it places a great burden on the electrolytic copper foil manufacturing apparatus.

In this embodiment, two types of anodes are used: the 1st anodes 3A, 3B and the 2nd anode 4. Although the mechanism is not elucidated, the layer plated in the vicinity of the second anode 4 at the bottom contains more organic compounds, decomposition products thereof, and chlorine as impurities than the layer plated in the vicinity of the first anode 3 at the top, and they is analyzed as nitrogen (N) or sulfur (S) or chlorine (Cl). Therefore, when the second anode 4 is arranged to be sandwiched between the first anodes 3A and 3B as shown in FIG. 2 , the copper layer with a relatively large amount of impurities plated in the vicinity of the second anode 4 is the first A copper foil having a three-layer structure schematically shown in Fig. 1 such as sandwiched in a copper layer having a relatively small amount of impurities plated in the vicinity of the anode 3 is obtained.

1 shows a layer 1A plated near the first anode 3A, a central plating layer 2 plated near the second anode 4, followed by a layer 1B plated near the first anode 3B. is schematically shown.

The copper foil of the three-layer structure does not only need to have a three-layer structure, but the ratio of the thickness of the central plating layer 2 is important. When the central plating layer 2 is relatively thin, rigidity is insufficient, and when the central plating layer 2 is relatively thick, flexibility is insufficient. This ratio is the current density of the second anode 4 and the current density of the first anode 3 (3A, 3B), and the total anode length of the second anode 4 (the first anode 3 (3A, 3A, 3B))) and the sum of the lengths of the second anode (4)).

The current density in the second anode 4 is preferably 10 to 80% of that of the first anode 3 (3A, 3B), particularly preferably 30 to 60%. When the current density of the second anode 4 is less than 10% of that of the first anode 3, the length of the second anode 4 to the total length of the anode in order to secure the ratio of the central plating layer 2 The ratio must be greatly increased, and as a result, the overall current density is greatly reduced, and production efficiency is reduced, so it is better to avoid it. In addition, when the ratio is higher than 80%, the difference in the impurity mixing amount between the layer 1 and the layer 2 decreases, and the properties required by the present invention cannot be obtained.

The ratio of the length of the second anode 4 to the total length of the anode is L4 [%], the current density of the first anode 3 (3A, 3B) is CD3, and the current density of the second anode 4 is CD4 It is preferable that it is in a range satisfying the following formula (1).

5≤((CD4*L4)/((CD3*(100-L4))

+(CD4*L4)))*100≤20 … (Equation 1)

In Equation 1, when L4 is less than 5, the external plating layers 1A and 1B are relatively too thick, so the rigidity is insufficient, and when L4 is greater than 20, the central plating layer 2 is relatively thick, so flexibility is insufficient.

In the SIMS intensity profile measured from the S-plane or M-plane surface in the thickness direction of the copper foil of this embodiment, the peak value of the intensity [number of counts] of nitrogen (N) or sulfur (S) or chlorine (Cl) is the thickness It is present in the central plating layer 2 near the central part of the direction. The central plating layer 2 is preferably present at a depth dp [μm] that satisfies 0.3x≤dp≤0.7x[μm] in a copper foil having a thickness of xμm.

In order to obtain the properties required by the present invention as described above, the ratio of the thickness of the central plating layer 2 is important, and the thickness of the central plating layer 2 is not too thin, that is, the peak of the SIMS intensity profile is not too sharp. , and that the thickness of the central plating layer 2 is not too thick, that is, the peak of the SIMS intensity profile is not too smooth.

Specifically, the intensity I at two locations spaced apart from the dp is an index. In the case where the thickness of the central plating layer 2 is not too thin, the intensity I at the position indicated by (dp±x/16) is an index, and for the case where the thickness of the central plating layer 2 is not too thick, the intensity at the position indicated by (dp±x/8) I is the index.

In SIMS of the present embodiment, the intensity I(dp) of the peak is expressed by the following formula

I(dp-x/16)≥1.5×I(dp-x/8)

I(dp+x/16)≥1.5×I(dp+x/8)

If it satisfies, the thickness of the central plating layer 2 is not too thin, so it is preferable, and also

I(dp)≥1.5×I(dp-x/8)

I(dp)≥1.5×I(dp+x/8)

If is satisfied, the thickness of the central plating layer 2 is not too thick, so it is not only preferable, but it is also preferable because the difference in the amount of impurities mixed between the outer plating layers 1A and 1B and the central plating layer 2 is clear. Also

I(dp)≥3.5×I(dp-x/8)

I(dp)≥3.5×I(dp+x/8)

If is satisfied, the difference in the amount of impurities mixed in the outer plating layers 1A and 1B and the central plating layer 2 becomes clear, which is preferable.

Here, in the SIMS of the present embodiment, the [number of counts] of the intensity I(dp) of the peak is preferably 100 or more, since noise cannot be distinguished unless the intensity [number of counts] is equal to or greater than a certain value. If I(dp) is greater than 100, it must be greater than or equal to 67 to satisfy 1.5×I(dp±x/8) of the above formula, and greater than or equal to 29 to satisfy 3.5×I(dp±x/8). It is a large enough value to be distinguished.

The three-layer structure copper foil which is one Embodiment of this invention which illustrated the said content in FIG. 1 WHEREIN: It demonstrates with reference to FIG. 3 which is a schematic diagram of the SIMS intensity profile measured in the thickness direction.

First, the peak value I(dp) of the intensity [number of counts] of nitrogen (N) or sulfur (S) or chlorine (Cl) exists at a depth dp [μm] that satisfies 0.3x≤dp≤0.7x[μm] do. Next, the intensity I (dp-x/16) that exists at a position deviating from -x/16[µm] in the thickness direction from dp[µm] is similarly at a position deviating from dp[µm] by -x/8[µm] 1.5 times or more of the existing intensity I (dp-x/8). Similarly, the intensity I (dp+x/16) at a position deviating +x/16[µm] from dp[µm] in the thickness direction is also present at a position deviating +x/8[µm] from dp[µm]. It becomes 1.5 times or more of the strength I(dp+x/8). Furthermore, I(dp) is 1.5 times or more (more preferably 3.5 times or more) of I(dp-x/8) and I(dp+x/8).

In the copper foil with three-layer structure which is one Embodiment of this invention illustrated in FIG. 1 WHEREIN: An example of the SIMS intensity profile which measured chlorine in the thickness direction from the S surface is shown in FIG. 16μm thick copper foil

4.8≤dp≤11.2[μm]

At a depth dp = 7.5 [μm] from the S plane that satisfies , there is an “analysis point A” at which the intensity [number of counts] of chlorine (Cl) shows a peak value of 3540, and the peak intensity I (7.5) end

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

It can be seen that the .

In addition, in the SIMS intensity profile of Fig. 4, a region with a high impurity content exists near the surface, but this is a practically unavoidable phenomenon in which impurities adhering to the surface of the copper foil near the analysis site are detected, and the copper layer is not affected. .

In this example, the measurement is performed from the S plane, but the same result is obtained also from the M plane.

An electrolytic copper foil with little impurity content is needed for the use by which flexibility is calculated|required as mentioned above. Moreover, an electrolytic copper foil with much impurity content is needed for the use which rigidity is calculated|required.

On the other hand, the electrolytic copper foil of the three-layer structure of the present embodiment illustrated in Fig. 1 has relatively little impurity content on the side of the surface layer where deformation is greatest during bending and stretching, and a relatively flexible copper layer (external plating layers 1A and 1B) )), and a copper layer (central plating layer 2) having a relatively high impurity content and relatively rigidity exists near the central portion where the load is concentrated. With such a configuration, it is desirable to provide an electrolytic copper foil in which flexibility to withstand repeated bending and expansion and contraction in a flexible wiring board as a wiring board application and rigidity to withstand repeated expansion and contraction in charging and discharging as a battery application are compatible. it becomes possible

As shown in Fig. 2, the second anode 4 is not necessarily disposed in the center of the entire length of the first anode 3 (3A, 3B). When the deformation on the M-plane side is the greatest, the second anode 4 is placed close to the side (left side in FIG. 2) where the surface of the rotating drum-shaped cathode 5 is immersed in the electrolyte 6 do. As a result, the copper layer having a relatively high impurity content is closer to the S-plane side than the central portion, and the copper layer having a relatively low impurity content on the M-plane side is thickened, so that the flexibility to deformation is higher. Similarly, in the case where the deformation on the S-plane side is greatest, the surface of the rotating drum-shaped cathode 5 is placed close to the side away from the electrolyte 6 (the right side in FIG. 2 ) and the second anode 4 is disposed. do.

In this way, the position of the layer 2 may move from the central portion to the S-plane side or the M-plane side depending on the position of the second anode 4 . For this reason, in this specification, the position of the center plating layer 2 is defined as the vicinity of a center part.

In addition, although the electrolytic copper foil of a three-layer structure is shown in FIG. 2, it goes without saying that an electrolytic copper foil of a four-layer or more structure can be manufactured by changing the current density more in multiple steps.

In addition, the copper foil used for wiring boards and batteries is heat-treated at 150 to 350° C. in the manufacturing process thereof. Even if such heat treatment is performed, the three-layer structure of the electrolytic copper foil of the present invention illustrated in FIG. 1 is maintained. More specifically, even when heat treatment is performed, a copper layer having a relatively low impurity content is present in the outer plating layer 1 near the surface portion, and a copper layer having a relatively high impurity content is present in the central plating layer 2 near the center portion. structure is maintained.

In addition, a method of manufacturing a three-layer structure as in the present invention using different equipment, electrolyte, and additive composition for each layer is also contemplated. However, compared with the single facility, electrolyte, and additive configuration of the present invention, it is easily expected that the manufacturing cost and yield will be significantly deteriorated, and furthermore, in the manufacture of thin foil, considerable difficulty is assumed, especially in the handling of the first layer, so it is not realistic. Can not do it.

Hereinafter, although this invention is demonstrated in detail based on the Example about copper foil of a three-layer structure, this invention is not limited to these.

(One) smelting

Example 1 to 9, comparative example 1 to 8

Table 1 shows manufacturing conditions, such as electrolyte solution composition. The copper sulfate plating solution having the composition shown in Table 1 was passed through an activated carbon filter for cleaning treatment, and the additive shown in Table 1 was similarly added to obtain a predetermined concentration.

The first anode 3 and the second anode 4 shown in Fig. 2 were adjusted to the current density and anode length shown in Table 2, and an electrolytic copper foil having a thickness of 12 μm was prepared by the rotary drum-type foil making device shown in Fig. 2 similarly. .

comparative example 9

Comparative Example 9 is a reproduction experiment of Example 3 described in Patent Document 4. The copper sulfate plating solution of the composition of Example 3 was reproduced and prepared. MPS-Na, DDAC polymer (Unisense manufactured by Senka Corporation: FPA100L) and hydrochloric acid were added as additives to this to a predetermined concentration. Electrolytic conditions to produce a electrolytic copper foil of 12μm thickness by a first and a current density of the electrolysis step the current density of the electrolytic 74A / dm ^2, a second step to 52A / dm ^2, the rotation drum jebak device.

[Table 1]

[Table 2]

The electrolytic copper foils of each Example and each comparative example were divided into three samples (Samples 1 to 3). Sample 1 was used for SIMS analysis, Sample 2 was used for a flexibility evaluation test, and Sample 3 was used for a stiffness evaluation test.

Details of each analysis and test are described below.

(One) SIMS analysis

Secondary Ion Mass Spectrometry (SIMS) analysis was performed using Sample 1. The analysis apparatus and analysis conditions are as follows.

analysis device

Product of Physical Electronics: “PHI6650”

analysis conditions

Primary ion: Cs ⁺ (5 kV, 100 nA)

Secondary (detection) ions

Nitrogen (N): 14N63Cu ^-

Sulfur (S): 34S ^-

Chlorine (Cl): 35Cl ^-

Sputter side: S side

Sputter area: 200μm×400μm

(Gate area (analysis area): 9% of the center of the sputter area)

Sputtering time: until penetrating the M-plane

Also, thickness x is 12μm, so 0.3x≤dp≤0.7x[μm] is

0.3×12≤dp≤0.7×12⇒3.6≤dp≤8.4

becomes

Judgment in SIMS analysis is nitrogen (N) or sulfur (S) or chlorine at a depth dp [μm] that satisfies 3.6 ≤ dp ≤ 8.4 [μm] in the SIMS intensity profile measured in the thickness direction from the S plane. There is a peak of (Cl), and the intensity I(dp) of the peak is

I(dp)≥100

I(dp-0.75)≥1.5×I(dp-1.5)

I(dp+0.75)≥1.5×I(dp+1.5)

I(dp)≥1.5×I(dp-1.5)

I(dp)≥1.5×I(dp+1.5)

○ (Pass),

I(dp)≥100

I(dp-0.75)≥1.5×I(dp-1.5)

I(dp+0.75)≥1.5×I(dp+1.5)

I(dp)≥3.5×I(dp-1.5)

I(dp)≥3.5×I(dp+1.5)

Samples satisfying each of these were evaluated as ◎ (excellent), and samples that did not were evaluated as × (disqualified). The results are shown in Table 3.

[Table 3]

(2) Flexibility evaluation test

Using Sample 2, a heat treatment of 300° C. × 1 hour, which is generally equivalent to the heat treatment applied in the manufacturing process for flexible wiring boards, was performed in a nitrogen atmosphere, and then cut into a 130 mm × 15 mm length test piece, and the copper foil was formed under the following conditions. The MIT flex test was performed until fracture. In this test, the softness|flexibility was evaluated by applying a light load to the extent that curvature does not come out to a sample and implementing a bending test.

Bending RadiusR: 0.38mm

Bend angle: ±135°

Bending speed: 175 times/min

Load: 10g

Samples that did not break after 800 or more bending cycles were evaluated as ○ (pass), especially samples that did not break after 1000 or more times were evaluated as ◎ (excellent), and samples that failed less than 800 times were evaluated as × (failed). Table 4 shows.

(3) Rigidity evaluation test

Using Sample 3, a heat treatment of 150° C. × 1 hour, which corresponds to the heat treatment normally applied in the manufacturing process for batteries, is performed in a nitrogen atmosphere, and then cut into a 130 mm × 15 mm length test piece, and the copper foil will break under the following conditions. MIT flexural tests were performed until In this test, rigidity was evaluated by applying a heavy load to the sample and performing a bending test.

Bending RadiusR: 0.80mm

Bend angle: ±135°

Bending speed: 175 times/min

Load: 500g

Samples that did not break after 300 or more bending cycles were evaluated as ○ (pass), especially samples that did not break after 400 or more were evaluated as ◎ (excellent), and samples that failed less than 300 times were evaluated as × (failed). Table 4 shows.

[Table 4]

Examples 1 to 9 are nitrogen (N) at a depth dp [μm] satisfying 3.6 ≤ dp ≤ 8.4 [μm] in the SIMS intensity profile measured in the thickness direction from the S plane, as is apparent from Table 3 ) or the intensity I(dp) of the peak of sulfur (S) or chlorine (Cl) is

I(dp)≥100

I(dp-0.75)≥1.5×I(dp-1.5)

I(dp+0.75)≥1.5×I(dp+1.5)

I(dp)≥1.5×I(dp-1.5)

I(dp)≥1.5×I(dp+1.5)

each has been satisfied. In particular, Examples 2, 3, and 6

I(dp)≥100

I(dp-0.75)≥1.5×I(dp-1.5)

I(dp+0.75)≥1.5×I(dp+1.5)

I(dp)≥3.5×I(dp-1.5)

I(dp)≥3.5×I(dp+1.5)

also met each. Accordingly, in Examples 1 to 9, the layer 2, which is a layer in which the content of nitrogen (N), sulfur (S), or chlorine (Cl) has a peak in the depth direction, is present in the vicinity of the center in a preferred thickness ratio. As a result, in Examples 1 to 9, the copper layer having a relatively high impurity content near the center portion and relatively stiff copper layer was sandwiched in a preferable ratio with the relatively flexible copper layer having a relatively low impurity content near the surface layer portion. It can be easily considered that the paper is made of copper foil with a three-layer structure.

As can be clearly seen from Table 4, these Examples 1 to 9 were excellent in both flexibility and rigidity, and in particular, Examples 2, 3, and 6 were all evaluated as ⊚ (excellent).

As is clear from Table 3, Comparative Examples 1 to 8 are sulfur (S) at a depth dp [μm] that satisfies 3.6≦dp≦8.4 [μm] in the SIMS intensity profile measured from the S plane in the thickness direction. ) or the intensity I(dp) of the peak of chlorine (Cl) is

I(dp)≥100

This point of analysis existed, but

I(dp-0.75)≥1.5×I(dp-1.5)

I(dp+0.75)≥1.5×I(dp+1.5)

I(dp)≥1.5×I(dp-1.5)

I(dp)≥1.5×I(dp+1.5)

None of them satisfies each. In Comparative Examples 1 to 8 showing such analysis results, there is no layer in which the impurity content in the thickness direction is substantially constant in the thickness direction and there is no layer showing a clear peak, or the layer 2 does not exist, or This means that the thickness is not preferable, and it can be considered that the comparative example does not have a three-layer structure with an appropriate thickness ratio like the example.

Accordingly, these Comparative Examples 1 to 8 are not compatible with flexibility and rigidity, as apparent from Table 4.

As can be clearly seen from Table 3 in Comparative Example 9 as well, chlorine (Cl) at a depth dp [μm] satisfying 3.6 ≤ dp ≤ 8.4 [μm] in the SIMS intensity profile measured in the thickness direction from the S plane. The intensity I(dp) of the peak is

I(dp)≥100

This point of analysis existed, but

I(dp-0.75)≥1.5×I(dp-1.5)

I(dp+0.75)≥1.5×I(dp+1.5)

I(dp)≥1.5×I(dp-1.5)

I(dp)≥1.5×I(dp+1.5)

None of them satisfies each. Comparative Example 9 is an analysis result in which I(dp) is higher than I(dp-1.5) and lower than I(dp+1.5), and the impurity content in the thickness direction is a sloping distribution with a low S-plane side and a high M-plane side. It can be considered that the comparative example does not have a three-layer structure of the copper layer as in the example.

In the current conditions in the manufacturing method described in Patent Document 4, which became the basis of Comparative Example 9, only lowering the current density after the first step electrolysis is described, and like the electrolysis conditions in the manufacturing method of the present invention, the central portion of the copper foil The operation to lower the current density is not performed only in the places corresponding to . Therefore, it is considered that the manufacturing method described in Patent Document 4 does not have a three-layer structure in which a copper layer having a relatively low impurity content and a relatively high impurity content and a rigid copper layer is present inside a copper layer having a relatively low impurity content.

In addition, in Patent Document 4 and the present invention, the properties required are completely different, and furthermore, in the main body of Patent Document 4, the impurity content in the copper foil is not mentioned. Therefore, it is very difficult to arrive at the present invention by assumption and analogy. .

According to the present invention, a three-layer structure in which a copper layer having a relatively low impurity content and a flexible copper layer has a relatively high impurity content and a rigid copper layer is present, so that flexibility and rigidity suitable for use in wiring boards and batteries are compatible. It becomes possible to provide the made electrolytic copper foil.

In addition, according to the present invention, a special electrolytic copper foil having a three-layer structure that requires a plurality of facilities and processes can be manufactured with a single facility, electrolyte, and additive composition, and furthermore, because it can be manufactured with a single equipment, electrolyte, and additive composition, productivity and excellent stability.

Explanation of symbols

1 (1A, 1B): a copper layer with relatively low impurity content and flexibility

2: Copper layer with relatively high impurity content and rigidity

3 (3A, 3B): first anode

4: second anode

5: cathode

6: Electrolyte

7: Electrolytic copper foil

Claims (6)

A central plating layer having a relatively high impurity content and rigidity,
An electrolytic copper foil comprising first and second outer plating layers having a relatively low impurity content and flexibility formed on both sides of the central plating layer,
In the thickness direction from the S-plane surface, which is the surface of the first outer plating layer, or the M-plane surface, which is the surface of the second outer plating layer, by SIMS (secondary electron mass spectrometry) method, primary ions are converted to cesium ions (Cs ⁺ ), In the SIMS (Secondary Electron Mass Spectrometry) intensity profile in which the acceleration voltage is 5 kV, the sputter region is 200 μm × 400 μm, and the analysis region is 9% of the central portion of the sputter region,
When the strength [number of counts] at the depth d [μm] from the S-plane surface or the M-plane surface is I(d), and the thickness of the electrolytic copper foil is x [μm],
In the central plating layer present at a depth dp [μm] that satisfies 0.3x≤dp≤0.7x[μm],
Nitrogen (N) measured as a secondary (detection) ion (14N63Cu ^{− ), or sulfur (S) measured as a secondary (detection) ion (34S −} ), or as a secondary (detection) ion (35Cl ⁻ ) There is a peak of chlorine (Cl),
The intensity I(dp) of the peak is
I(dp)≥100
I(dp-x/16)≥1.5×I(dp-x/8)
I(dp+x/16)≥1.5×I(dp+x/8)
I(dp)≥1.5×I(dp-x/8)
I(dp)≥1.5×I(dp+x/8)
Electrolytic copper foil, characterized in that each satisfies. Consists of a central plating layer having a relatively high impurity content and rigidity, and first and second outer plating layers having a relatively low impurity content and flexibility formed on both surfaces of the central plating layer,
In the thickness direction from the S-plane surface, which is the surface of the first outer plating layer, or the M-plane surface, which is the surface of the second outer plating layer, by SIMS (secondary electron mass spectrometry) method, primary ions are converted to cesium ions (Cs ⁺ ), In the SIMS (Secondary Electron Mass Spectrometry) intensity profile in which the acceleration voltage is 5 kV, the sputter region is 200 μm × 400 μm, and the analysis region is 9% of the central portion of the sputter region,
When the strength [number of counts] at the depth d [μm] from the S-plane surface or the M-plane surface is I(d), and the thickness of the electrolytic copper foil is x [μm],
In the central plating layer present at a depth dp [μm] that satisfies 0.3x≤dp≤0.7x[μm],
Nitrogen (N) measured as a secondary (detection) ion (14N63Cu ^{− ), or sulfur (S) measured as a secondary (detection) ion (34S −} ), or as a secondary (detection) ion (35Cl ⁻ ) There is a peak of chlorine (Cl),
The intensity I (dp) of the peak is,
I(dp)≥100
I(dp-x/16)≥1.5×I(dp-x/8)
I(dp+x/16)≥1.5×I(dp+x/8)
I(dp)≥3.5×I(dp-x/8)
I(dp)≥3.5×I(dp+x/8)
Electrolytic copper foil, characterized in that each satisfies. A flexible wiring board using the electrolytic copper foil according to claim 1 or 2. A battery using the electrolytic copper foil according to claim 1 or 2. delete delete

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