KR20200121689A - metallic multi-layer thin film and method thoereof - Google Patents

Abstract

The present invention relates to a multilayer metal foil excellent in mechanical strength and a method for manufacturing the same. A plurality of metal layers included in the multilayer metal foil are formed with plating solutions having different concentrations of organic additives, and at least one plating layer among the plurality of metal layers is a recrystallization inhibiting layer capable of inhibiting growth of crystal grains.

Description

Metallic multi-layer thin film and method thoereof}

The present invention relates to a multilayer metal foil comprising a plurality of plating layers and to a use thereof.

Metal foil is used for various substrates or batteries, and research related to this is being actively conducted. In particular, copper foil is a metallic copper thin film manufactured through electroplating, and is used for wiring of electronic circuits such as printed circuit boards (PCBs), flexible substrates such as FCCL (Flexible Copper Clad Laminate), or cathode collectors for secondary batteries. It is widely used to connect the whole.

In most fields in which copper foil is used, thin copper foil is preferred. However, as the thickness of the copper foil decreases, the strength decreases. Therefore, a technology for manufacturing a high strength thin copper foil is required.

Korean Patent Publication No. 1997-0015792 discloses a technology for manufacturing a high-strength electrolytic copper foil for a printed circuit board through a pulsed current waveform, and Korean Patent No. 10-0571561, Korean Patent Publication No. 10-2006-0114588 and Korea Registered Patent No. 10-2013-0077240 discloses a technology capable of manufacturing a high strength electrolytic copper foil by adding various additives to a plating solution. In addition, there are various technologies related to the manufacture of high-strength copper foil, but the cause of the increase in the strength of the copper foil seems to be somewhat unclear.

Accordingly, the inventors of the present invention have come to develop a technology for manufacturing a high-strength multilayer metal foil by accurately grasping the factors that influence the increase in the strength of the metal foil through microstructure analysis of the metal foil including copper foil, and analyzing this.

Korean Patent Publication No. 1997-0015792 Korean Patent Registration No. 10-0571561 Korean Patent Publication No. 10-2006-0114588 Korean Patent Registration No. 10-2013-0077240

The present invention relates to a high-strength multilayer metal foil manufactured by controlling the degree of recrystallization occurring in a metal layer when forming a plating layer, and a method of manufacturing the same.

The present invention provides a multilayer metal foil comprising a plurality of plating layers and at least one plating layer of the plurality of plating layers is a recrystallization inhibiting layer.

The present invention provides a method of manufacturing a high-strength multilayer metal foil by adjusting the concentration of an organic additive contained in a plating solution for forming a recrystallization inhibiting layer and a plating solution for forming a plating layer excluding the recrystallization inhibiting layer.

The multilayer metal foil of the present invention includes a recrystallization inhibiting layer that can control the degree of recrystallization that occurs when the plating layer is formed, so that the size of crystal grains inside the plating layer is limited to the thickness of each of the plating layers included in the multilayer metal foil regardless of the thickness of the entire multilayer metal foil. It is possible to provide a high-strength multilayer metal foil having a high strength lamellar structure.

1 is a view comparing the microstructure of a cross-section after heat treatment (80°C, 30 minutes) of a multilayer metal foil including two recrystallization inhibiting layers and a metal foil not including a recrystallization inhibiting layer according to the present invention (diffusion prevention layer is a plating layer) It represents the recrystallization inhibiting layer to which heat treatment was applied after formation). Initially, the appearance of the recrystallization inhibiting layer is almost similar regardless of the presence or absence of the recrystallization inhibiting layer. However, if the recrystallization is induced by performing heat treatment, the recrystallization inhibiting layer is less likely to recrystallize than the plating layer other than the recrystallization inhibiting layer, so the size of the crystal grains is reduced. It is smaller than the suppression layer in the other plating layer, and it is possible to suppress the size of crystal grains generated in the plating layer other than the recrystallization suppression layer.
2 shows the result of sheet resistance reduction according to the heat treatment time at 80°C, and shows the relationship between the JGB concentration and the impurities (C, N, S, O, H) of the plating electrodeposition layer (R _O is the initial sheet resistance, and the graph is Show R/R _O ).
3 shows a plating layer formed with each plating solution to which JGB was added at different concentrations (0.00mM, 0.01mM, 0.03mM, 0.10mM, 0.20mM, and 1.00mM), and EBSD mapping after heat treatment at 80°C for 90 minutes. ) Show the result.
4 is a result of measuring the EBSD of the cross section of the copper foil after forming a single electrolytic copper foil having a thickness of 10 μm using a plating with JGB added at a concentration of 0.01 mM where recrystallization occurs well, and heat treatment (A) and excluding the twin boundary plane. The result (B) is shown by displaying the size of the grain in color as the grain boundary.
5 is an example of the manufacturing method of the present invention, showing a process of manufacturing an electrolytic multilayer copper foil by forming a laminated plating layer including a recrystallization inhibiting layer on a cathode substrate.
6 shows a SEM photograph of a cross section of a 2 μm×5 layer multilayer copper foil. The recrystallization generation layer and the recrystallization inhibiting layer, in which recrystallization occurs easily, were alternately plated to have a total thickness of 10 µm. The plating thickness of the recrystallization layer is 2 μm, and the thickness of the plating layer acting as a recrystallization inhibiting layer is about 0.01 μm. The recrystallization inhibiting layer hardly affects the total thickness, but the 0.01 μm plating layer used as the recrystallization inhibiting layer is effective. It can be seen that connection of crystal grains that may occur between the recrystallized layers can be suppressed.
7 shows the EBSD analysis results of each copper foil cross section after forming copper foils of 10 layers, 5 layers, 3 layers, 2 layers and a single layer structure and performing heat treatment (all copper foils have the same total thickness as 10 μm) . The color of the crystal grains was changed according to the size, and the microstructure was indicated by color (the red color, the larger the crystal grain size, and the blue color, the smaller the grain size), and the size distribution of the crystal grains was expressed as a histogram.
8 shows a graph of the Hall-Petch relationship through the average grain size and yield strength generated in the recrystallization layer of the multilayer copper foil.

Hereinafter, the present invention will be described in detail. Unless otherwise defined, terms used in this specification should be interpreted as generally understood by those of ordinary skill in the relevant field. The drawings and embodiments of the present specification are for a person skilled in the art to easily understand and implement the present invention, and contents that may obscure the gist of the invention in the drawings and examples may be omitted, and the present invention is limited to the drawings and examples. It does not become.

The present invention relates to a high strength multilayer metal foil having a lamella structure and a method of manufacturing the same.

In the manufacture of the metal layer, the strength of the metal layer may be enhanced by the inherent strength of the metal and the dispersion strengthening and precipitation hardening by impurities introduced in the metal layer manufacturing process. In terms of microstructure, as the size of grains included in the metal layer decreases, the yield strength tends to increase, which can be explained through the Hall-Petch relationship. In general bulk metals, mechanical properties can be adjusted by controlling the size of crystal grains through plastic processing and heat treatment, and in the manufacture of electrolytic copper foil, various organic additives can be added or plating conditions can be adjusted during the plating process. It can enhance the mechanical strength of copper foil.

According to an embodiment of the present invention, when an electrolytic copper foil is manufactured by adding an organic additive, a plating layer (plated thin film) is formed in the form of nano-sized crystal grains immediately after plating, and the degree of recrystallization can be controlled by adjusting the type and concentration of the organic additive. have.

According to another embodiment of the present invention, by controlling the degree of recrystallization, a plating layer in which recrystallization does not occur easily can be formed between the plating layers in which recrystallization occurs relatively easily, thereby manufacturing a multilayer metal foil having a lamella structure, and the degree of recrystallization is different. A multilayer metal foil including a plurality of plating layers may have excellent mechanical strength compared to other single metal foils or multilayer metal foils.

The multilayer metal foil of the present invention will be described in more detail with reference to FIG. 1 as follows. Referring to FIG. 1, it can be seen that in the case of a multilayer metal foil including a recrystallization inhibiting layer, the size of crystal grains after recrystallization according to heat treatment is formed to the maximum thickness of each plating layer. That is, the recrystallization inhibiting layer acts as a film that prevents the connection of crystal grains formed in each plating layer (expressed as a diffusion barrier in Fig. 1), so that the size of the crystal grains generally determined depending on the thickness of the plating thin film is determined by the thickness of the plated thin film. You will be able to adjust it to your liking regardless of. In the recrystallization inhibiting layer, since recrystallization is less likely to occur than that of the plating layer other than the recrystallization inhibiting layer, the size (growth) of the crystal grains of the plating layer other than the recrystallization inhibiting layer can be limited, and finally, a multilayer metal foil having a lamellar structure can be formed. The multi-layered metal foil having a lamellar structure has excellent mechanical strength compared to a single metal foil or a multi-layered metal foil of the same thickness due to its structural characteristics.

The multilayer metal foil of the present invention includes a plurality of plating layers, and at least one or more of the plurality of plating layers may be formed as a recrystallization inhibiting layer.

The plating layer corresponding to the recrystallization inhibiting layer and the plating layer other than the recrystallization inhibiting layer may be formed of plating solutions having different concentrations of the organic additives. More specifically, the concentration of the organic additive included in the plating solution used to form the recrystallization inhibiting layer may be higher than the concentration of the organic additive included in the plating solution used to form the plating layer other than the recrystallization inhibiting layer.

According to an embodiment of the present invention, two types of plating solutions having different concentrations of organic additives may be prepared, and a recrystallization inhibiting layer formed of a plating solution having a high concentration of the organic additive may be formed to be inserted between the plating layers other than the recrystallization inhibiting layer. . The multilayer metal foil is preferably formed through an electroplating method such that plating layers other than the recrystallization inhibiting layer and the recrystallization inhibiting layer are alternately stacked, but is not limited thereto.

More specifically, for convenience of explanation, the recrystallization inhibiting layer is a layer in which recrystallization does not occur easily, and the plating layer other than the recrystallization inhibiting layer is expressed as a layer in which recrystallization occurs easily. Two types of plating solutions having different concentrations of organic additives are prepared, and the plating solution having a relatively low concentration of the organic additive is referred to as the first plating solution, and the plating solution having a relatively high concentration of the organic additive is referred to as the second plating solution. After preparing a substrate, forming a first plating layer on the substrate with a first plating solution, forming a second plating layer on the first plating layer with a second plating solution, forming a third plating layer on the second plating layer again with the first plating solution, and repeating this. A multilayer metal plate in which a plurality of metal layers are stacked may be manufactured. In this case, the 2n-1 plating layer (n = natural number) formed of the first plating solution having a relatively low concentration of the organic additive compared to the second plating solution becomes a plating layer in which recrystallization occurs easily by heat treatment. The 2n plating layer (n = natural number) formed of the second plating solution in which the concentration of the organic additive is relatively higher than that of the first plating solution becomes a plating layer in which recrystallization does not occur easily due to heat treatment. Since the 2n-th plating layer, in which recrystallization is difficult to occur, is inserted between the 2n-1 plating layers in which recrystallization occurs easily, there is a very high possibility that grain growth in the 2n-1 plating layer is limited to the thickness of the corresponding thin film. In this way, the suppression of grain growth of the 2n-1 plating layer by the 2n plating layer, which is difficult to recrystallize, can increase the yield strength of the metal foil due to grain refinement, and quantitatively, it can be confirmed according to the Hall-Petch equation. do.

The plating solution used in the manufacture of the multilayer metal foil of the present invention can be prepared in various ways according to the desired multilayer metal foil, and the plating solution for forming the recrystallization inhibiting layer and the plating layer other than the recrystallization inhibiting layer are formed by varying the concentration of the organic additive contained in the plating solution. It can be prepared by dividing it into a plating solution for use.

When producing a copper foil according to the present invention, the plating solution has a copper ion (Cu ^2+), Chloride (Cl ^-) to be used for the current collector of the various substrate or a battery, may include an acid and an organic additive, but are not limited to . In the case of manufacturing copper foil by electroplating, it may vary depending on the conditions of the plating process, and preferably, the concentration of copper ions contained in the plating solution is 0.1 to 1 M, the concentration of sulfuric acid is 0.1 to 2 M, and the concentration of chloride ions is 0.01 to It may contain 0.1 mM, but is not limited thereto. The organic additive may include, but is not limited to, a plating inhibitor, a plating accelerator, and a leveling agent. In the organic additive, the plating inhibitor is polyethylene glycol or polypropylene glycol (PPG) having a molecular weight of 1000 to 10000, and it is preferable to include 0.01 to 0.5 mM, but is not limited thereto. In the organic additive, the plating accelerator is SPS (bis-(3-Sulfopropyl) disulfide) or MPSA (3-mercapto-1-propane sulfonic acid), and it is preferable to include 0.01 to 0.2 mM, but is not limited thereto. In the organic additive, the leveling agent is preferably JGB (Janus green B, C ₃₀ H ₃₁ ClN ₆ ) and may be included in an amount of 0.01 to 0.3 mM.

According to an embodiment of the present invention, different plating solutions for forming plating layers other than the recrystallization inhibiting layer and the recrystallization inhibiting layer may be prepared by adjusting the concentration of the leveling agent among organic additives included in the plating solution when manufacturing a multilayer copper foil according to the present invention. I can. When JGB is added as a smoothing agent, JGB is trapped into the plating layer during the electroplating process, and as the concentration of JGB increases, the reduction rate of the sheet resistance of the plating layer may become slower. Since a decrease in the rate of sheet resistance reduction means slow recrystallization, a plating solution having a high concentration of a leveling agent among organic additives can be used to form a recrystallization inhibiting layer.

According to another embodiment of the present invention, a leveling agent among organic additives may be added in an amount of 0.1 mM or more, preferably 0.2 mM or more, to a plating solution used to form a recrystallization inhibiting layer when manufacturing a multilayer copper foil according to the present invention, When using JGB as a leveling agent, adding JGB at a concentration of 0.05 to 1.0mM, 0.1 to 1.0mM, 0.15 to 1.0mM, 0.2 to 1.0mM, preferably 0.05 to 0.3mM, more preferably 0.15 to 0.3mM Crystal grain growth in the plating layer can be suppressed very effectively.

The multilayer metal foil according to the present invention can be manufactured according to the following manufacturing method.

In the method of manufacturing a multilayer metal foil including a plurality of plating layers and at least one of the plurality of plating layers is a recrystallization inhibiting layer, a plating solution for forming a recrystallization inhibiting layer and a plating solution for forming a plating layer excluding the recrystallization inhibiting layer are prepared. Step to do; Forming a plurality of plating layers on the substrate with a plating solution for forming a recrystallization inhibiting layer and a plating solution for forming a plating layer excluding the recrystallization inhibiting layer; And a heat treatment step, wherein the organic additive included in the plating solution for forming the recrystallization inhibiting layer may be a method of manufacturing a multilayer metal foil having a higher concentration than the organic additive included in the plating solution for forming the plating layer excluding the recrystallization inhibiting layer.

In the manufacturing method of the present invention, the method of forming the plating layer is preferably an electroplating method, and various manufacturing methods may be used depending on the type and shape of the desired multilayer metal foil.

In the manufacturing method of the present invention, the conditions for forming the plating layer may be different depending on the type and shape of the multilayer metal foil desired.

A more specific method of manufacturing a multilayer copper foil according to the manufacturing method of the present invention is as follows. The method for manufacturing a multilayer copper foil according to the present invention comprises: preparing a plating solution containing copper ions, chlorine ions, sulfuric acid and an organic additive; Preparing a first plating solution and a second plating solution having a higher level of the leveling agent of the organic additive than the first plating solution; Forming a plurality of plating layers on a substrate using a first plating solution and a second plating solution, but forming a plurality of plating layers including at least one recrystallization inhibiting layer formed from a second plating solution; And it may be a manufacturing method including a heat treatment step. It is preferable to repeatedly form a plating layer formed by the first plating solution (a plating layer other than a recrystallization suppressing layer) and a plating layer formed by the second plating solution (a recrystallization suppressing layer) so as to cross each other, but is not limited thereto. The organic additive may include a plating inhibitor, a plating accelerator, and a leveling agent, and the leveling agent is preferably Janus green B (JGB, C ₃₀ H ₃₁ ClN ₆ ). The concentration of the leveling agent in the second plating solution is 0.1mM or more, preferably 0.2mM or more. More specific examples of the concentration of each plating solution, for example, a first plating solution of 0.01 to less than 0.1mM and a second plating solution of 0.1mM to 1mM or a first plating solution of 0.01 to 0.2mM and a second plating solution of 0.2mM to 1mM Can be

In the present invention, even if the recrystallization inhibiting layer is formed to have a thickness that does not affect the overall thickness of the multilayer copper foil, the multilayer copper foil of the present invention can be manufactured. For example, even if the thickness of the recrystallization inhibiting layer is formed to a thickness of 5/10000 to 15/10000 of the total thickness, the multilayer copper foil of interest in the present invention can be manufactured.

According to an embodiment of the present invention, when manufacturing a multilayer copper foil, plating layers other than the recrystallization inhibiting layer and the recrystallization inhibiting layer may be formed by an electroplating method. In this case, the size of the crystal grains may be determined by adjusting plating process parameters corresponding to plating solution additives, current density, etc. according to the shape (number of plating layers, etc.) or thickness of the multilayer copper foil. When forming the multilayer copper foil, the temperature of the plating solution is preferably 20 to 60°C, and the current density is preferably 10 to 600 mA/cm 2, but is not limited thereto. The stirring may be magnetic bar stirring, paddle stirring, plating liquid flow and nozzle spraying stirring, stirring by movement of the object to be plated itself, or air stirring, but is not limited thereto. In the heat treatment process after forming a plurality of plating layers including a recrystallization inhibiting layer by electroplating, the heat treatment temperature is 100°C or less, 65 to 95°C, 70 to 90°C, preferably 75 to 85°C, and the heat treatment time is preferably 100 minutes or less. It is 85 to 95 minutes, but is not limited thereto.

In the manufacturing method of the present invention, various substrates may be used depending on the manufacturing process or analysis method of the metal foil, and a copper seed layer may be deposited on the substrate by a method such as sputtering before forming the metal layer.

The multilayer metal foil manufactured by the manufacturing method of the present invention may be a high strength metal foil having a total thickness of 10 μm or less.

The multilayer metal foil manufactured according to the present invention can be used for manufacturing one or more products selected from the group consisting of a printed circuit board (PCB), a flexible substrate, and a negative electrode current collector for a secondary battery. It can be used for products containing.

Hereinafter, an embodiment for carrying out the present invention will be described. The examples correspond to one example for carrying out the present invention, and the present invention should not be construed as being limited by the examples.

Checking the difference in grain growth by controlling the concentration of organic additives

A plating solution containing copper ions (Cu ²⁺ ), sulfuric acid, HCl, and organic additives was prepared. As organic additives, PEG (polyethylene glycol, molecular weight 1000 ~ 10000), SPS (bis-(3-Sulfopropyl) disulfide) and JGB (Janus green B, C ₃₀ H ₃₁ ClN ₆ ) were used. In all plating solutions used in the examples, the concentration of copper ions is 0.1 to 1 M (mol/L), the concentration of sulfuric acid is 0.1 to 2 M, the concentration of HCl is 0.01 to 0.1 mM, the concentration of PEG is 0.01 to 0.5 mM, and the concentration of SPS. The concentration was the same within the range of 0.01 to 0.2 mM. Among the organic additives, JGB was used differently for each plating solution within the range of 0.00 to 1.0 mM in 0.00mM, 0.01mM, 0.03mM, 0.10mM, 0.20mM and 1.00mM.

Electrolytic plating was performed with the positive electrode made of soluble copper electrode and the negative electrode made of stainless steel (STS). Electroplating process conditions were a current density of 30 mA/cm 2, a temperature of a plating solution of 25° C., and a stirring speed of 200 rpm.

After the metal layer was formed by electroplating, heat treatment was performed at 80° C. to measure the recrystallization growth, and sheet resistance was measured using a four point probe. And, the concentration of impurities (C, N, S, O, H) in the plating layer was measured by GDS (glow discharge spectroscopy). In addition, the final heat-treated sample was subjected to EBSD microstructure analysis using a field emission scanning electron microscopy (FESEM) device equipped with a Hikari XP EBSD (electron backscattered diffraction) camera.

The measurement results of plating layers formed with plating solutions having different JGB concentrations among organic additives are as follows.

As the concentration of JGB among organic additives increased, it was confirmed that the sheet resistance deceleration rate was slow, and recrystallization took place slowly through the slowing of the reduction rate of sheet resistance. In particular, a plating layer formed with a plating solution containing 0.2mM JGB In, the sheet resistance decreases slowly after the initial sheet resistance decrease of about 7%, which is distinguished from other plating layers in which sheet resistance decreases slowly after the initial sheet resistance decrease of about 15-20% (FIG. 2(A)). In addition, by GDS analysis, it was confirmed that C, N, H elements, etc., which are impurities inside the plating layer, increase in proportion to the concentration of JGB. Accordingly, it could be understood that grain growth was inhibited by diffusion and pinning to the grain interface (Fig. 2(B)).

Crystal grains were sufficiently grown in the plating layer formed of a plating solution having a low concentration of JGB in the organic additives (0.00mM, 0.01mM, 0.03mM). However, crystal grain growth was suppressed in the plating layer formed with a plating solution to which high concentration (0.10mM, 0.20mM, 1.00mM) JGB was added. Specifically, in the case of the plating solution having a concentration of 0.1mM, some crystal grains were grown to confirm the structure coexisting with the initial nano-sized fine grains, and in the case of the plating solution of 0.2mM or more, it was confirmed that the grain growth inside the plating layer was significantly suppressed (Fig. 3). ).

As a result of EBSD analysis of the cross section after forming a plating layer with a thickness of 10 μm with a plating solution containing JGB of 0.01 mM concentration where recrystallization occurs well, the size of the crystal grains excluding the twin boundary is determined. Looking at, there are only one or two grains in the thickness direction, and in this case, it can be predicted that the grains are large and the strength decreases (FIG. 4).

From the above results, it can be expected that the concentration of impurities formed in the plating layer can be controlled by controlling the concentration of JGB, which is a smoothing agent, among organic additives, and it is possible to form a recrystallization inhibiting layer that suppresses grain growth.

Fabrication of multilayer copper foil including recrystallization inhibiting layer and measurement of physical properties

A plating solution containing 0.01 mM JGB is used as the first plating solution to form a plating layer other than the recrystallization inhibiting layer (plating layer where recrystallization occurs easily), and a plating solution containing 0.2 mM JGB is used as a recrystallization inhibiting layer (plating layer that does not easily recrystallize). It was used as the second plating solution for A multilayer copper foil was manufactured so that a plating layer other than a recrystallization inhibiting layer (a plating layer in which recrystallization occurs easily) and a recrystallization inhibiting layer (a plating layer in which recrystallization does not easily occur) are alternately stacked using the first plating solution and the second plating solution alternately. The recrystallization inhibiting layer was formed to be inserted between the plating layers other than the recrystallization inhibiting layer, and the thickness was very thin, about 0.01 μm, so as not to affect the change of the overall thickness. Plating layers other than the recrystallization inhibiting layer were formed to be positioned below and above the recrystallization inhibiting layer with a uniform thickness (FIG. 5).

As for the multilayer copper foil, 1 μm × 10 layer multilayer copper foil, 2 μm × 5 layer multilayer copper foil (Fig. 6), 3.3 μm × 3 layer multilayer copper foil and 4 5 μm × 2 layer multilayer copper foil were prepared, and 10 μm single copper foil was also manufactured. (The number of layers in the multilayer copper foil of the examples means the number of plating layers other than the recrystallization inhibiting layer for convenience, and the recrystallization inhibiting layer was not included in the number of layers because the thickness was so thin that it did not affect the total thickness. For example, 1 µm × The 10-layer multilayer copper foil has 10 plating layers other than the recrystallization inhibiting layer having a thickness of 1 μm, and each of nine recrystallization inhibiting layers having a thickness of 0.01 μm are formed between the plating layers other than the recrystallization inhibiting layer).

A 1 μm×10 layer multilayer copper foil, a 2 μm×5 layer multilayer copper foil, a 3.3 μm×3 layer multilayer copper foil, and four 5 μm×2 layer multilayer copper foils and a 10 μm single copper foil were prepared and analyzed through EBSD. As a result of measuring the size of the crystal grains without considering the twin boundary plane, it was confirmed that the size of the crystal grains was almost proportional to the thickness of the plated layer in the multilayer copper foil in which the thicknesses of the plating layers other than the recrystallization inhibiting layer were 2 μm and 3 μm (FIG. 7). These results showed that recrystallization can be induced locally in the plating layer other than the recrystallization inhibiting layer through the insertion of the recrystallization inhibiting layer in the multilayer copper foil, and the size of the crystal grains can be made finer than the plating thickness.

1㎛ × 10 layer multilayer copper foil, 2㎛ × 5 layer multilayer copper foil, 3.3㎛ × 3 layer multilayer copper foil, and 5㎛ × 2 layer multilayer copper foil four and 10㎛ single copper foil was manufactured and yield strength and tensile strength through uniaxial tensile test Was measured. The measurement results are shown in [Table 1] below.

Strength of multilayer copper foil and single copper foil including recrystallization inhibiting layer The thickness of the plating layer (plating layer where recrystallization occurs well), not the recrystallization inhibiting layer Average grain size
(㎛: Ignore the twin boundary) Yield strength
(kgf/mm ² ) The tensile strength
(kgf/mm ² ) 1㎛ 0.8 31.71 34.78 2㎛ 2.3 28.17 31.78 3㎛ 3.1 25.77 29.20 5㎛ 3.9 25.80 29.02 10㎛ 4.3 25.20 28.64

Looking at the results in [Table 1], it can be seen that the thickness of the plating layer (hereinafter referred to as'recrystallization layer)' rather than the recrystallization inhibiting layer decreases, and the yield strength and tensile strength increase, and the thickness of the recrystallization layer increases. It can be seen that the change in the intensity value is slowed at 3㎛ or more. In addition, when the thickness of the recrystallization layer is 3 μm or less, the size of the crystal grains increases linearly, whereas when the thickness of the recrystallization layer exceeds 3 μm, the change in size of the crystal grains is slowed down. In the recrystallized layer of 3㎛ or less with a relatively large change in strength, the values of the variables are calculated as follows through fitting using the Hall-Petch equation, and Hall- through the average grain size and yield strength through FIG. You can check the Petch relationship.

는 25MPa,

가 0.12MPa·^1/2인데 비해 위와 같이

는 상당히 큰 값을 나타내는 것을 확인할 수 있다. 통상의 벌크 구리의 결정립이 수십 ㎛인데 비해 본 발명의 다층 동박에서 결정립의 크기는 벌크 구리 결정립보다 1/10 정도로 작고, 평균 결정립의 감소와 유기첨가제에 의한 불순물 유입에 의한 분산강화 등의 영향으로 항복강도가 증가한 것으로 볼 수 있다. Looking at the approximate equation, the actual bulk (bulk) copper

Is 25 MPa,

Is 0.12 MPa· ^1/2 , as above

You can see that represents a fairly large value. Compared to the general bulk copper grain size of several tens of μm, the size of the grain in the multilayer copper foil of the present invention is about 1/10 smaller than that of the bulk copper grain, and due to the influence of the decrease in average grain size and dispersion strengthening due to the introduction of impurities by an organic additive. It can be seen that the yield strength has increased.

Claims (12)

Including a plurality of plating layers,
At least one plating layer among the plurality of plating layers is a recrystallization inhibiting layer.
The method of claim 1,
The recrystallization inhibiting layer is a multilayer metal foil formed of a plating solution in which a concentration of an organic additive included in a plating solution for forming a plating layer is higher than that of an organic additive included in a plating solution for forming a plating layer other than the recrystallization inhibiting layer.
The method of claim 2,
The plating solution is a multilayer metal foil containing copper ions, chlorine ions, sulfuric acid and an organic additive.
The method of claim 2,
The organic additive is a multilayer metal foil comprising a plating inhibitor, a plating accelerator, and a smoothing agent.
The method of claim 4,
The smoothing agent JGB (Janus green B, C ₃₀ H ₃₁ ClN ₆ ) is a multilayer metal foil.
The method of claim 5,
The recrystallization suppression layer included in the multilayer metal foil is a multilayer metal foil formed of a plating solution to which the concentration of JGB (Janus green B, C ₃₀ H ₃₁ ClN ₆ ) is higher than that of a plating layer other than the recrystallization suppression layer.
The method of claim 6,
The recrystallization inhibiting layer is a multilayer metal foil formed of a plating solution having a concentration of JGB (Janus green B, C ₃₀ H ₃₁ ClN ₆ ) contained in the plating solution of 0.1 mM or more.
A method of manufacturing a multilayer metal foil including a plurality of plating layers and at least one plating layer of the plurality of plating layers is a recrystallization inhibiting layer,
Preparing a plating solution for forming a recrystallization inhibiting layer and a plating solution for forming a plating layer excluding the recrystallization inhibiting layer;
Forming a plurality of plating layers on a substrate with a plating solution for forming the recrystallization inhibiting layer and a plating solution for forming a plating layer other than the recrystallization inhibiting layer; And
Including a heat treatment step,
An organic additive included in the plating solution for forming the recrystallization inhibiting layer is a method of manufacturing a multilayer metal foil having a higher concentration than the organic additive included in the plating solution for forming the plating layer excluding the recrystallization inhibiting layer.
The method of claim 8,
The organic additive includes a plating inhibitor, a plating accelerator, and a leveling agent, and the leveling agent included in the plating solution for forming the recrystallization suppression layer is higher than that of the leveling agent included in the plating solution for forming the plating layer excluding the recrystallization inhibiting layer. A method of manufacturing a multi-layered metal foil having a high level.
The method of claim 9,
The smoothing agent is JGB (Janus green B, C ₃₀ H ₃₁ ClN ₆ ) a method of manufacturing a multilayer metal foil.
A substrate comprising the multilayer metal foil according to any one of claims 1 to 7.
A secondary battery negative electrode current collector comprising the multilayer metal foil of any one of claims 1 to 7.

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