JP6082609B2 - High strength, high heat resistant electrolytic copper foil and manufacturing method thereof - Google Patents

Description

  The present invention relates to an electrolytic copper foil, for example, an electrolytic copper foil containing tungsten (W) or the like, and a method for producing the same.

  Conventionally, electrolytic copper foil has been used in various fields including rigid printed wiring boards, flexible printed wiring boards, and electromagnetic shielding materials.

  Among these applications, in applications related to a flexible printed wiring board (hereinafter referred to as “FPC”) bonded to a polyimide film, a suspension material of a hard disk drive (hereinafter referred to as “HDD”) or tape automated bonding (hereinafter referred to as “FPC”). There has been a demand for improving the strength of copper foil as a material called “TAB”.

  Most suspensions installed in HDDs have been replaced by wire-type suspensions that have been used in the past as the capacity increases, and suspensions with integrated wiring that have stable buoyancy and positional accuracy relative to the disk that is the storage medium. ing.

  This wiring-integrated suspension includes (1) a type of flexible printed circuit board called FSA (Flex Suspension Assembly) method, which is bonded using an adhesive, (2) CIS (Circuit Integrated Suspension) method A type in which amic acid, which is a precursor of polyimide resin, is shaped, then polyimide is formed, and wiring is formed by plating the resulting polyimide. (3) TSA (trace suspension assembly) method There are three types: a type called a stainless steel foil-polyimide resin-copper foil three-layer structure that is processed into a predetermined shape by etching.

  Among them, the TSA suspension can easily form a flying lead by laminating a high-strength stainless steel foil with a copper foil, and has a high degree of freedom in shape processing and is relatively inexpensive and dimensional. Widely used because of its high accuracy.

  In the suspension formed by the TSA method, a laminate is manufactured using a material with a stainless steel foil thickness of about 12-30 μm, a polyimide layer thickness of about 5-20 μm, and a copper foil thickness of about 7-14 μm. Has been.

  In the production of the laminate, first, a polyimide resin precursor-containing liquid is applied onto a stainless steel foil serving as a base. After coating, after removing the solvent by preheating, further heat treatment is performed to polyimidize, and then a copper foil is superimposed on the polyimide resin layer that has been polyimidized and laminated by thermocompression bonding at a temperature of about 300 ° C. And the laminated body which consists of a stainless steel layer / polyimide layer / copper layer is manufactured.

  With this heating at about 300 ° C., there is almost no dimensional change in the stainless steel foil. However, when a conventional electrolytic copper foil is used, the electrolytic copper foil is annealed at a temperature of about 300 ° C., recrystallization proceeds and softens, and a dimensional change occurs. For this reason, the laminated body warps after laminating, which hinders the dimensional accuracy of the product.

In order to prevent warping of the laminate after lamination, the copper foil is required to have as small a dimensional change upon heating as possible, and usually requires an area change of 0.1% or less.
Conventionally, a rolled copper alloy foil is used as a copper foil that satisfies this requirement. The rolled copper alloy foil is not easily annealed at a temperature of about 300 ° C., has little dimensional change during heating, and little mechanical strength change.

Rolled copper alloy foil is a copper alloy containing copper as a main component and containing at least one element other than copper, such as tin, zinc, iron, nickel, chromium, phosphorus, zirconium, magnesium, and silicon, by rolling. Foil. Some of these rolled copper alloy foils are not easily annealed by heating at about 300 ° C. depending on the type and combination of elements, and some of the tensile strength, 0.2% yield strength, elongation, etc. do not change so much.
For example, a rolled copper alloy foil such as Cu-0.2 mass% Cr-0.1 mass% Zr-0.2 mass% Zn (Cu-2000 ppm Cr-1000 ppm Zr-2000 ppm Zn) can be used as an HDD suspension material in addition to a TSA suspension. It is preferably used.

Also in the TAB material, as in the case of the TSA suspension and the HDD suspension material, it is required to increase the strength of the copper foil.
In a TAB product, a plurality of terminals of an IC chip are directly bonded to inner leads (flying leads) arranged in a device hole located substantially at the center of the product.
Bonding at this time is performed by applying a constant bonding pressure by instantaneously energizing and heating using a bonding apparatus (bonder). At this time, there is a problem that the inner lead obtained by etching the electrolytic copper foil is excessively stretched by being pulled by the bonding pressure.

  By increasing the strength of the electrolytic copper foil, it becomes difficult for the inner leads to sag and break. Therefore, if the strength of the electrolytic copper foil is too small, there is a problem that sagging occurs in the inner lead due to plastic deformation, and if it is significant, it breaks.

  In the case of TAB use, a two-layer FPC in which a copper foil and a polyimide layer are bonded together, or a three-layer FPC in which a copper foil, a polyimide layer, and an adhesive layer are bonded together is used. In a three-layer FPC, an epoxy adhesive is used when polyimide is laminated to a copper foil, and is laminated at a temperature of about 180 ° C. In a two-layer FPC using a polyimide-based adhesive, bonding is performed at a temperature of about 300 ° C.

  Even if the copper foil has a high mechanical strength in a normal state, it does not make sense to be softened when bonded to polyimide. Conventional high strength electrolytic copper foil has a high mechanical strength in the normal state, and the mechanical strength hardly changes even when heated at around 180 ° C. However, when heated at about 300 ° C., it is annealed and recrystallized. Since it progresses, it softens rapidly and mechanical strength falls remarkably.

As an electrolytic copper foil having excellent mechanical strength, various studies have been conducted as shown below.
For example, Patent Document 1 discloses a low-roughened electrolytic copper foil having an elongation at 180 ° C. of 10.0% or more as a copper foil suitable for printed wiring board applications and negative electrode current collector applications for lithium secondary batteries. Have been described.
Then, using sulfuric acid-copper sulfate aqueous solution as an electrolytic solution, polyethyleneimine or a derivative thereof, a sulfonate of an active organic sulfur compound, a chlorine ion (chloride ion) at a concentration of 20 to 120 mg / L, and an oxyethylene-based surface activity at a predetermined concentration It is said that the above electrolytic copper foil can be obtained by the presence of the agent.

Patent Document 2 discloses that the tensile strength at 25 ° C. measured within 20 minutes from the completion of electrodeposition is 820 MPa or more, and the electric strength relative to the tensile strength at 25 ° C. measured within 20 minutes from the completion of electrodeposition. An electrolytic copper foil is described in which the rate of decrease in tensile strength at 25 ° C. measured at the elapse of 300 minutes from the completion of deposition is 10% or less.
Then, using the sulfuric acid-copper sulfate aqueous solution as an electrolytic solution, hydroxyethyl cellulose, polyethyleneimine, sulfonic acid salt of an active organic sulfur compound, acetylene glycol, and chloride ions having a concentration of 20 to 120 mg / L are present to form the above electrolytic copper foil. It is supposed to be obtained.

Further, Patent Document 3 discloses an electrodeposited copper foil having a particle structure having an average particle size of up to 10 μm, which is essentially free of columnar particles and twin boundaries, and the particle structure is substantially uniform. A controlled low profile electrodeposited copper foil with a randomly oriented grain structure is described.
This electrodeposited copper foil has a maximum tensile strength at 23 ° C. in the range of 87,000 to 120,000 psi (600 MPa to 827 MPa), and a maximum tensile strength at 180 ° C. of 25,000 to 35,000 psi (172 MPa to 172 MPa). 241 MPa).

Patent Document 4 describes a method for producing an electrolytic copper foil with an electrolytic solution obtained by adding tungsten or a tungsten compound and further glue and 20 to 120 mg / L of chloride ions in a sulfuric acid copper sulfate electrolytic solution. ing. As its effect, it is described that the hot elongation at 180 ° C. is 3% or more, the roughness of the rough surface is large, and a copper foil with less pinholes can be produced.
Therefore, the inventors repeatedly conducted an experiment in which tungsten or a tungsten compound was added to a sulfuric acid-copper sulfate electrolytic solution, and then electrodeposited with an electrolytic solution containing Nika and 20 to 120 mg / L of chloride ions. Reference 4 further examined that a copper foil having a target hot elongation at 180 ° C. of 3% or more, a rough surface having a large roughness, and less pinholes can be produced. However, as a result of analyzing this copper foil, it was found that tungsten was not co-deposited in this electrolytic copper foil. That is, an electrolytic copper alloy foil (copper-tungsten-based copper alloy foil) could not be obtained (see Comparative Example 4 described later).
Therefore, according to the method described in Patent Document 4, it is impossible to produce an electrolytic copper alloy foil that has a high mechanical strength in a normal state and is unlikely to decrease in mechanical strength even when heated at a high temperature.
Opinions about this cause will be described later.

Patent Document 6 describes a dispersion strengthened electrolytic copper foil in which copper is present as fine crystal grains and SnO ₂ is dispersed as ultrafine particles.
In Patent Document 6, copper ion, sulfate ion and tin ion and an organic additive such as polyethylene glycol are contained in a sulfuric acid copper sulfate electrolytic solution, and a bubbling treatment with an oxygen-containing gas is performed to add SnO into the electrolytic solution. It is described that ₂ ultrafine particles are produced and the dispersion strengthened electrolytic copper foil is obtained using this electrolytic solution.

Furthermore, Patent Document 7 describes an electrolytic copper foil containing silver (Ag).
Patent Document 7 describes that an electrolytic copper foil is obtained from this electrolytic copper foil by using a sulfuric acid copper sulfate electrolytic solution to which a silver salt providing a predetermined concentration of silver ions is added. Silver is said to be co-deposited in this electrolytic copper foil.

Japanese Patent No. 4120806 Japanese Patent No. 4273309 Japanese Patent No. 3,270,637 Japanese Patent No. 3238278 JP 2009-221592 A JP 2000-17476 A Japanese Patent No. 3934214

  However, in the case of the electrolytic copper foils described in Patent Documents 1 to 4, 6 and 7, all of them have high mechanical strength in the normal state, but when heated at a high temperature of about 300 ° C., the mechanical strength is remarkably high. descend. The “normal state” means a room temperature at 25 ° C., 1 atm, and a normal pressure environment.

In the case of the electrolytic copper foils described in Patent Documents 1 to 4 and 6, all use a sulfuric acid-copper sulfate electrolyte solution, and the types of additives are different in Patent Documents 1 to 4 and 6, but both are organic. A compound is used as an additive (referred to as an organic additive in this document).
Many organic additives usually have an effect of suppressing crystal growth, and are considered to be taken into crystal grain boundaries. In this case, the mechanical strength tends to improve as the amount of the organic additive taken into the crystal grain boundary increases (see Patent Document 5).
In the case of the electrolytic copper foils described in Patent Documents 1 to 4 and 6 in which the organic additive is incorporated into the crystal grain boundary, all have high mechanical strength in the normal state, but when heated at a high temperature of about 300 ° C. Significantly decreases the mechanical strength. This is considered that when the organic additive taken into the crystal grain boundary is heated at a high temperature of about 300 ° C., it decomposes, and as a result, the mechanical strength decreases.

  On the other hand, in the electrolytic copper foil described in Patent Document 7 that does not use an organic additive, the mechanical strength is remarkably increased when heated at a high temperature of about 300 ° C. as in the electrolytic copper foil using the organic additive. It turns out that it falls.

Accordingly, an object of the present invention is to provide an electrolytic copper foil that has a high mechanical strength in the normal state and that is not easily thermally deteriorated even when heated at a high temperature of, for example, about 300 ° C.
Furthermore, the present invention provides an electrolytic copper foil having high conductivity, high tensile strength and excellent heat resistance by incorporating into the electrolytic copper foil a metal that has conventionally been metallurgically impossible to form an alloy with copper. Providing is another issue.

As a result of intensive studies, the present inventors have conducted electrolytic deposition (also referred to as electrodeposition or electrodeposition) from an electrolytic solution in which the organic additive is not used and the chloride ion concentration is adjusted to a predetermined low concentration. It was found that an electrolytic copper foil having a high normal mechanical strength and a small thermal deterioration of the mechanical strength even when heated at about 300 ° C. can be obtained.
In addition, the present inventors mixed an aqueous solution in which a metal salt of a metal present as an oxide in a solution having a pH of 4 or less and a metal salt of a metal that co-deposited with copper in an electrolytic copper foil were mixed with an aqueous copper sulfate solution. The metal oxide ultrafine particles and a part thereof are reduced by performing foil formation using the electrolyte obtained by adjusting the chloride ion concentration to a predetermined low concentration. The present inventors have found that an electrolytic copper foil having high electrical conductivity, high tensile strength and excellent heat resistance can be obtained by incorporating ultrafine particles of metal and metal co-deposited with copper into the electrolytic copper foil.
The present invention has been completed based on these findings.

That is, according to the present invention, the following means are provided.
(1) metal or oxides thereof present as an oxide in the pH4 following acidic conditions, and, viewed including the metals of codeposition of copper,
The metal present as an oxide under acidic conditions of pH 4 or lower is either W, Mo or Te,
The electrolytic copper foil which contains 10 ppm or more of the metal which exists as an oxide in the acidic condition of the said pH 4 or less, or its oxide as a metal .
( 2 ) The electrolytic copper foil according to ( 1 ), which contains 100 ppm or more of a metal eutectoid with copper .
(3) metal eutectoid and copper is either Ag or Bi (1) or tensile strength is not less than 900MPa of the electrolytic copper foil (4) 300 ℃ after heat treatment according to (2) (1) - electrolytic copper foil according to any one of (3).
(5) conductivity is 70% IACS or more (1) electrolytic copper foil according to any one of - (4).
(6) The electrolytic copper foil according to any one of (1) to (5), which does not contain an organic additive.
( 7 ) Any one of ( 1 ) to (6) manufactured using an electrolytic solution containing an aqueous copper sulfate solution, an aqueous solution of a metal salt of the above metal, and a chloride ion of 3 mg / L or less. The electrolytic copper foil as described in the item.
( 8 ) Prepare an electrolyte solution by adding hydrochloric acid or a water-soluble chlorine-containing compound to a mixed solution of an aqueous solution of copper sulfate and an aqueous solution of a metal salt of the metal so as to have a chloride ion concentration of 3 mg / L or less, The method for producing an electrolytic copper foil according to any one of ( 1 ) to (7) , wherein an electrolytic copper foil is produced by electrolytic deposition using the electrolytic solution.
(9) The method for producing an electrolytic copper foil according to (8), wherein an electrolytic copper foil is produced without using an organic additive.
In the present invention, the “acidic condition of pH 4 or lower” is preferably a condition in an aqueous solution. In addition, “a metal present as an oxide in an acidic solution having a pH of 4 or less” means, for example, M.I. Pourbaix's Atlas of electrochemical equilibria in aqueous solutions. In the potential-pH diagram shown in Pergamon Press (1966), the electrolyte is selected from the metal components present as oxides at a pH of 4 or less, and the electrolyte is added with these metal components. As a result of particle size distribution measurement by DLS (Dynamic Light Scattering), the added metal component is detected as solid particles.

Since the electrolytic copper foil of the present invention is obtained by taking in metal by two different uptake mechanisms with respect to copper as a base material, due to the synergistic effect of both, the mechanical strength in the normal state is large, and about Even when heated at a high temperature of 300 ° C., thermal deterioration of mechanical strength is small. One of the uptake mechanisms is to take in metals such as W, Mo, Ti and Te as ultrafine particles by electrolytic deposition, which has conventionally been difficult to be alloyed with copper metallurgically. Under acidic conditions such as an aqueous solution having a pH of 4 or less, ultrafine particles of a metal oxide existing as an oxide or ultrafine particles of a metal that has been partially reduced are taken into an electrolytic copper foil. The other is a mechanism in which metal is co-deposited with copper in the electrolytic copper foil and taken into the metal lattice (that is, a mechanism for alloying).
In the present specification, a metal present as an oxide or an oxide thereof in a liquid having a pH of 4 or less is also referred to as “dispersed precipitated metal”, and a metal that is eutectoid with copper in an electrolytic copper foil is also referred to as “eutectoid metal”. Moreover, the said dispersion | distribution precipitation metal and eutectoid metal are match | combined, and it is called the metal taken in in the electrolytic copper foil. Here, the mechanical strength refers to tensile strength, 0.2% yield strength, and the like.
This electrolytic copper foil of this invention can be used suitably for various uses, such as a flexible printed wiring board (FPC) and a negative electrode collector for lithium ion secondary batteries.
Moreover, the manufacturing method of the electrolytic copper foil of this invention is suitable as a method of manufacturing the said electrolytic copper foil with a simple method.

The apparatus schematic of SAXS (USAXS).

(Composition of electrolytic copper foil)
The electrolytic copper foil of the present invention contains a metal (dispersed precipitated metal) that exists as an oxide under acidic conditions such as an aqueous solution having a pH of 4 or less as ultrafine particles of the oxide or as ultrafine particles of a reduced metal. At the same time, the electrolytic copper foil of the present invention contains a metal that is co-deposited with copper (eutectoid metal) in the metal lattice. The electrolytic copper foil of the present invention preferably contains chlorine in an amount of less than 10 ppm (including chlorine-free, that is, includes a chlorine content of 0 ppm), and more preferably contains chlorine in an amount of less than 1 ppm.
First, it is preferable that the metal (dispersed precipitated metal) present as an oxide in the acidic condition of pH 4 or lower, preferably in a sulfuric acid acidic liquid, is at least one of W, Mo, Ti, or Te. More preferably, any one of these metal species is included.
Here, in the electrolytic copper foil of this invention, the metal which exists as an oxide in the acidic condition of pH 4 or less is either W, Mo, or Te.
In the present invention, the content (uptake amount) of these metals in the electrolytic copper foil is 10 ppm or more in terms of the metal, preferably 80 to 2610 ppm, more preferably 100 to 2500 ppm, and 110 to 2460 ppm. Further preferred is 210 to 2460 ppm. When this content is too small, the heat resistance effect is remarkably reduced, and the tensile strength after heating at 300 ° C., for example, becomes as low as 80% or less as a ratio to the normal tensile strength. On the other hand, if the content is too large, no further improvement is seen in the effect of improving the tensile strength, and the conductivity is lowered.

And it is preferable that it is at least 1 sort (s) of Ag and Bi as a metal (eutectoid metal) co-deposited with copper. More preferably, any one of these metal species is included.
The content (uptake amount) of these metals in the electrolytic copper foil is preferably 100 ppm or more in terms of the metal. When this content is too small, the heat resistance effect is remarkably reduced, and the tensile strength after heating at 300 ° C., for example, becomes as low as 80% or less as a ratio to the normal tensile strength.

(Measuring method of the content of the dispersed precipitated metal and the eutectoid metal in the electrolytic copper foil produced by the foil)
After dissolving a certain weight of electrolytic copper foil with an acid, the contents of precipitated metal and eutectoid metal in the solution were determined by ICP emission spectroscopic analysis.

  As described above, since the electrolytic copper foil of the present invention takes in metal by two different uptake mechanisms, the content exceeds the limit of the amount of metal when two types of metal are taken up by a single uptake mechanism. can do. Thereby, the electrolytic copper foil of the present invention has high strength and high heat resistance that cannot be achieved by a single uptake mechanism due to the synergistic effect of the dispersed precipitated metal and the eutectoid metal.

That is, when two types of metals are to be taken in by a single take-in mechanism, heat resistance reaches its peak because it can be taken in only up to the upper limit derived from the take-in mechanism.
However, in the electrolytic copper foil of the present invention, it is possible to take in up to the upper limit of each uptake mechanism by taking in with two kinds of uptake mechanisms. Can be improved).
Further, in the electrolytic copper foil of the present invention, metal is taken in as ultrafine particles by electrolytic deposition, and the ultrafine particles affect the surrounding crystal structure and exert an inhibitory effect on recrystallization. As a result, the dispersed precipitated metal stays at the crystal grain boundary as it is in the form of ultrafine particles without being taken into the base material, and dramatically improves the strength after heating in the normal state. In addition, the electrolytic copper foil of the present invention has an effect of making the energy required for recrystallization different because the lattice of the parent phase itself is different from pure copper by eutectoid. Thereby, since heat softening due to heating is unlikely to occur, strength reduction after heating is suppressed or strength is improved.
Due to the synergistic effect of the above action, the electrolytic copper foil of the present invention has high strength and high heat resistance that cannot be achieved by a single uptake mechanism.

  Next, the content (uptake amount) of chlorine in the electrolytic copper foil is less than 10 ppm. When the chlorine content of the electrolytic copper foil is 10 ppm or more, the amount of dispersed precipitated metal and eutectoid metal taken up is extremely reduced, and the effect of improving the tensile strength and heat resistance is significantly reduced.

(Crystal grains and dispersed particles of electrolytic copper foil)
In the electrolytic copper foil of the present invention, copper forms an alloy together with a eutectoid metal to form a base material as fine crystal grains, and the metal oxide of the dispersed precipitated metal and a metal partially reduced thereof are ultrafine particles. As dispersed in the base material.
The particle size (GS) of fine crystal grains formed by copper and a eutectoid metal, which is a base material, is preferably 5 to 500 nm, and more preferably 5 to 50 nm.
On the other hand, the particle diameter of the metal oxide ultrafine particles of the dispersed precipitated metal is preferably 0.5 to 100 nm, and more preferably 0.5 to 2 nm. Moreover, when the metal in which a part of the metal oxide of the dispersed precipitated metal is reduced is present as ultrafine particles, the particle diameter is preferably 0.5 to 20 nm, more preferably 0.5 to 2 nm. .

(Measuring method of particle diameter of fine crystal grains of alloy formed by copper and eutectoid metal, and measuring method of particle diameter of ultrafine particles of metal oxide of dispersed precipitated metal and partially reduced metal)
The particle diameter of the fine crystal grains of the alloy formed of copper and the eutectoid metal is measured by measuring the image of the polished surface of the copper foil by SIM (scanning ion microscopy) to obtain the average particle diameter. be able to.
On the other hand, the particle diameter of the dispersed precipitated metal can be measured using a small angle X-ray scattering method. Small-angle X-ray scattering is a method for directly measuring the size and shape of an object of 1 nm to 1 μm in a bulk sample, and the distribution and fluctuation of nanoscale atoms and molecules.

  For example, when a tungsten-added metal foil is used as a sample, SAXS (small angle X-ray scattering) and USAXS (ultra small angle X-ray scattering) measurement are performed. The SAXS (USAXS) measurement is performed at the industrial use beam line BL19B2 of Spring-8 (super photo ring 8GeV, high-intensity synchrotron radiation facility).

  FIG. 1A shows a simple optical axis diagram of SAXS (USAXS) measurement. Incident X-rays 14 generated from the X-ray source 13 including the shutter 15 are irradiated to the sample 27 through the monochromator 17, the first pinhole 19, the second pinhole 21, and the third pinhole 25. From incident X-rays 14 irradiated on the sample 27, transmitted X-rays 29 that pass through the sample 27 and scattered X-rays 31 scattered by the sample 27 are generated. The detector 35 is provided at the end of the optical axis and detects transmitted X-rays 29 or scattered X-rays 31.

  When the scattered X-ray 31 is measured by the detector 35, as shown in FIG. 1B, the incident X-ray 14 is irradiated to the sample 27 without passing through the attenuator 23, and the transmitted X-ray 29 is irradiated by the beam stopper 33. The light is shielded and the scattered X-ray 31 is measured by the detector 35.

  When measuring the transmitted X-ray 29 with the detector 35, as shown in FIG. 1C, the intensity of the incident X-ray 14 is weakened with the attenuator 23, and then the sample 27 is irradiated with the incident X-ray 14. The transmitted X-ray 35 is measured by the detector 35 without shielding the transmitted X-ray 29 by the beam stopper 33.

Let L be the distance from the sample 27 to the detector 35. A location where the transmitted X-ray 29 transmitted through the sample 27 reaches the detector 35 is denoted by O, and a location where the scattered X-ray 31 scattered from the sample 27 at the angle θ reaches the detector 35 is denoted by A. If AO = r, tan θ = r / L and θ is obtained. Hereinafter, the horizontal axis of the SAXS and USAXS data is described as q (nm ⁻¹ ) expressed by the equation (1).
q = 4πsin θ / λ (1)

λ is the wavelength of incident X-rays. In the measurement, λ = 0.068 nm, the distance from the sample to the detector is L = 4.2 m (SAXS), and L = 42 m (USAXS). The range of measurement is q = 0.05-4 (nm < ^-1 >). The detector uses a semiconductor two-dimensional detector Pilatus. After performing SAXS measurement, it is confirmed that there is no anisotropy by looking at the mapping of the intensity of the two-dimensional X-ray, and one-dimensionalization is performed.

The X-ray scattering from WO ₃ is extracted by subtracting the SAXS intensity of pure copper from the SAXS data of the copper foil containing tungsten, and the scattered X-ray is used to calculate the number density of WO ₃ using this extracted data. The scattering cross section is obtained from the above, and fitting is performed. The measured X-ray scattering intensity I (q) and the scattering cross section dΣ / dΩ (q) are in the relationship of equation (2).

  Φ0 is the intensity of the direct beam, η is the correction term by the detector, S is the irradiation area, T is the transmittance, and D is the thickness. Since Φ0, η, and S are basically constant, if A = Φ0 · η · S, A = const, and A is a value unique to the apparatus.

  Regarding A, glassy carbon measured with an apparatus that has previously determined Φ0, η, and S is also measured with SPring-8, BL19B2, and A is calculated. Symbols S, C, and N in the formula (2) are abbreviations of Sample, Cell, and Noise, respectively. In the present invention, Sample is copper foil and Cell is pure copper. When the scattering cross section is obtained from equation (2), equation (3) is obtained.

  On the other hand, the scattering cross section is expressed by equation (4).

ｄΣ／ｄΩ（ｑ）は散乱断面積、Δρ２は原子散乱因子、ｄＮは粒子数密度、Ｖは粒子体積、Ｆは粒子の形状因子、Ｎ（ｒ）は粒径分布関数である。ＴＥＭ観察の結果から、量子の形状因子は球体とした（式（５））。

dΣ / dΩ (q) is a scattering cross section, Δρ2 is an atomic scattering factor, dN is a particle number density, V is a particle volume, F is a particle shape factor, and N (r) is a particle size distribution function. From the result of TEM observation, the quantum form factor was a sphere (formula (5)).

Fitting was performed using the equation (3) with the scattering cross section: dΣ / dΩ (q) obtained from the scattered X-ray intensity as the variable q.
The particle size of the dispersed precipitated metal can be determined by performing the above measurement analysis.

(Method for producing electrolytic copper foil)
The electrolytic copper foil of the present invention can be produced by the following production method.
First, hydrochloric acid or a water-soluble chlorine-containing compound is added to a mixed solution of an aqueous copper sulfate solution and an aqueous solution of the metal salt of the dispersed precipitated metal and eutectoid metal so as to have a chloride ion concentration of 3 mg / L or less. A liquid is prepared, and an electrolytic copper foil is produced by electrolytic deposition using the electrolytic solution.
1. Electrolyte composition As the electrolyte, a copper sulfate-containing aqueous solution prepared to have a copper ion concentration of 50 to 120 g / L, a free sulfate ion concentration of 30 to 150 g / L, and a chloride ion concentration of 3 mg / L or less is used as a basic electrolyte composition. . Here, in the present invention, not containing chloride ions means that the chloride ion concentration is 3 mg / L or less.
Copper ions and free sulfate ions can be obtained by adjusting an aqueous copper sulfate solution so as to give the respective ion concentrations. Alternatively, the concentration of these ions may be adjusted by adding sulfuric acid to an aqueous copper sulfate solution that gives a predetermined copper ion concentration.
The chloride ion may be provided by hydrochloric acid or a water-soluble chlorine-containing compound. As the water-soluble chlorine-containing compound, for example, sodium chloride, potassium chloride, ammonium chloride and the like can be used.
2. Addition of metal or metal salt An aqueous metal salt solution in which the metal salt is dissolved is added to an electrolyte having a pH of 4 or less, preferably a sulfuric acid electrolyte to disperse ultrafine metal oxide particles in the electrolyte. This is taken into the copper foil during electrolytic deposition.
First, as the metal salt of the dispersed precipitated metal, any metal salt that ionizes in a solvent such as water (pH is higher than pH 4 and lower than pH 9), alkali (pH 9 or higher), hot concentrated sulfuric acid and becomes an oxide at pH 4 or lower can be used. Well, there are no particular restrictions on the type. Examples of these metal salts include oxyacid salts when the metal is W or Mo, and sulfates when the metal is Ti. For example, tungstates such as sodium tungstate, potassium tungstate, and ammonium tungstate, molybdates such as sodium molybdate, potassium molybdate, and ammonium molybdate, and titanium salts such as titanium sulfate can be used.
Strictly speaking, any metal salt may be used as long as it is ionized in a solvent and becomes an oxide at pH 4 or lower. For example, tellurium oxide can be used in the present invention because it is ionized in hot concentrated sulfuric acid.

  Next, the metal to be co-deposited is not particularly limited as long as it is a metal that co-deposits with copper by electrodeposition. As examples of these metals, silver nitrate, silver chloride, silver oxide, and Bi can be used when the metal is Ag.

  The concentration of the aqueous solution is preferably 1 mg / L to 500 mg / L (as the metal), more preferably 10 mg / L to 250 mg / L (as the metal). When this concentration is too low, the target metal is not sufficiently taken into the copper foil. On the other hand, if this concentration is too high, the target metal will be excessively incorporated into the copper foil, resulting in a decrease in electrical conductivity, saturation of the effect of improving heat resistance, and conversely the decrease in heat resistance. May fall.

In the present invention, in order to adjust to the predetermined chloride concentration, it is preferable that the water used for preparing the electrolytic solution and the aqueous metal salt solution contains as little chloride ions as possible. In this respect, it is preferable to prepare the aqueous metal salt solution by dissolving the metal salt in pure water. Here, the pure water is preferably water containing as little metal ions and chloride ions as possible. Specifically, water having a chloride ion concentration of 3 mg / L or less is preferable, and water having a chloride ion concentration of less than 1 mg / L is more preferable.
3. Manufacturing conditions The conditions during electrolytic deposition are as follows.
Current density 30-100 A / dm ²
Temperature 30-70 ° C
Under the above conditions, an electrolytic copper foil having a foil thickness of, for example, 12 μm can be manufactured.

The reason why the metal salt aqueous solution is added to the electrolytic solution is to allow the metal incorporated into the copper foil to be present in the aqueous solution as ions and to be introduced into the electrolytic solution. By adopting such a charging form, ultrafine particles of metal oxide are formed when metal ions of the dispersed precipitated metal are converted into oxides in an electrolyte solution having a pH of 4 or lower. At the same time, the metal ions of the eutectoid metal co-deposit with copper to form fine crystal grains as a base material. On the other hand, even if the metal salt is directly added to the electrolytic solution, the ultrafine particles of the metal oxide of the dispersed precipitated metal are not formed, and thus the effect of improving the tensile strength and heat resistance cannot be obtained. Moreover, even if it tries to take in two types of metals using the uptake | capture mechanism of any one of electrolytic deposition or eutectoid, the uptake | capture amount will be limited and the synergistic effect which used two types of metals will not be acquired.
The chloride ion in the electrolytic solution is suppressed to a low concentration of 3 mg / L or less because the adsorption of metal oxide ultrafine particles by the specific adsorption of chlorine on the copper surface during the precipitation of metal oxide ultrafine particles of dispersed precipitate metal. It is for preventing inhibiting. When the concentration of chloride ions is higher than 3 mg / L, the metal uptake into the electrolytic copper foil is reduced, and the effect of improving the tensile strength and heat resistance is drastically lowered.

(Dislocation inhibition effect)
The metal material including the copper foil is recrystallized by heating to a temperature higher than the recrystallization temperature, and the crystal grains are coarsened. As a result, the strength is lowered. Here, the starting point of the recrystallization process is the movement of dislocations (unstable states such as lattice defects). In the electrolytic copper foil of the present invention, the metal oxide ultrafine particles are dispersed in the matrix phase, thereby inhibiting the movement of dislocations around the fine particles. Therefore, since it will not soften unless it heats at higher temperature, high heat resistance is acquired.
In this document, this is referred to as “high dislocation inhibition effect”.

(Foil thickness of electrolytic copper foil)
There is no restriction | limiting in particular in the foil thickness of the electrolytic copper foil of this invention, What is necessary is just to adjust according to the required foil thickness in a use application. For example, it may be 3 to 20 μm for a flexible printed wiring board (FPC). On the other hand, what is necessary is just to set it as 5-30 micrometers for the negative electrode electrical power collector for lithium ion secondary batteries.

(Physical properties of electrolytic copper foil)
The electrolytic copper foil of the present invention preferably has a conductivity of 55% IACS or more, more preferably 65% IACS or more, and particularly preferably 70% IACS or more. There is no restriction | limiting in particular in the upper limit of electrical conductivity, and it may exceed 100% IACS.
The electrolytic copper foil of the present invention preferably has a normal tensile strength value of 500 MPa or more, and more preferably 600 MPa or more. There is no restriction | limiting in particular in the upper limit of the tensile strength in a normal state, Usually, it is 1100 Mpa or less.
In the electrolytic copper foil of the present invention, the ratio of the tensile strength value after the heat treatment at 300 ° C. to the normal tensile strength value is preferably 50% or more, more preferably 80% or more, and this ratio is 90%. % Or more is particularly preferable. The upper limit of this ratio is not particularly limited and may exceed 100% (that is, the tensile strength increases after heating).

One preferable embodiment of the electrolytic copper foil of the present invention is an electrolytic copper foil containing tungsten as a dispersed precipitation metal, silver as a eutectoid metal, and the balance consisting of copper and inevitable impurities.
Here, containing tungsten as the dispersed precipitated metal means that it is dispersed in the base material as ultrafine particles of tungsten oxide. However, there is a case where only a part of the tungsten oxide is reduced to metal tungsten during the process of taking tungsten into the base material. In the present invention, the electrolytic copper alloy foil contains tungsten, in addition to the case where the ultrafine particles of tungsten oxide are dispersed in the base material, and in the base material as such ultrafine particles of metal tungsten. It is meant to include cases where they exist in a distributed manner.
In this document, such ultrafine particles of tungsten oxide and ultrafine particles of metallic tungsten are collectively referred to as tungsten contained in the electrolytic copper foil.
Moreover, containing silver as a eutectoid metal means that silver is co-deposited with copper and incorporated into a metal lattice (alloyed).

  The amount of tungsten contained in the electrolytic copper foil is preferably in the range of 10 to 2000 ppm, more preferably in the range of 280 to 2000 ppm. Here, the amount of tungsten contained in the electrolytic copper foil is a content obtained by converting a tungsten component contained as ultrafine particles of tungsten oxide or metallic tungsten into metallic tungsten. If the content of tungsten is too small, the effect of addition hardly appears. On the other hand, if the added amount of tungsten is too large, the effect of the addition is saturated and the effect of improving the physical properties is not seen despite the high cost.

That is, in the electrolytic copper foil containing tungsten in an amount of less than 10 ppm, the mechanical strength after heating at 300 ° C. for 1 hour (hereinafter abbreviated as “300 ° C. × 1H”) is almost the same as when no tungsten is contained. Will drop significantly.
As the added amount of tungsten increases, the decrease in strength after heating at 300 ° C. × 1 H decreases, but the effect becomes saturated when the content increases to some extent. The upper limit of the effective addition amount is about 2000 ppm.
The unit “ppm” used for displaying the content of the component means “mg / kg”. Moreover, it is 0.0001 mass% = 1ppm.

  Moreover, the range of 300-10000 ppm is preferable and, as for content of silver contained in electrolytic copper foil, the range of 1000-10000 ppm is more preferable. The upper limit value is not necessarily 10000 ppm or less, but since the improvement of the effect is not observed even if it exceeds 10000 ppm, it is practical to set it to 10000 ppm or less.

The electrolytic copper foil of the present embodiment is obtained by electrolyzing a copper sulfate-based electrolytic solution having a pH of 4 or less containing copper ions and tungsten oxide and silver ions generated from a tungsten salt at a pH of 4 or less.
The tungsten salt contained in the electrolytic solution may be any salt that dissolves in a sulfuric acid-copper sulfate solution, and examples thereof include sodium tungstate, ammonium tungstate, and potassium tungstate. Examples of silver contained in the electrolyte include silver nitrate, silver chloride, and silver oxide.

In the electrolytic copper foil of the present embodiment, tungsten oxide obtained by changing tungstate ions generated from tungsten salt in an electrolyte solution having a pH of 4 or less in an electrolyte solution having a low chloride ion concentration is obtained by using the electrolyte solution. From the analysis, it is considered that the tungsten oxide (WO ₃ , W ₂ O ₅ , WO _2, etc.) is taken into the electrolytic copper foil as it is or as reduced metallic tungsten. Here, these tungsten oxides (WO ₃ , W ₂ O ₅ , WO ₂ etc.) or metallic tungsten are dispersed in the base material as the ultrafine particles.
Further, silver ions in the electrolyte solution having a low chloride ion concentration are co-deposited with copper by electrodeposition to form a base material with copper and silver.
That is, the electrolytic copper foil of the present invention is a sulfuric acid-copper sulfate electrolytic solution having a low chloride ion concentration, and is formed by electrolytic deposition from an electrolytic solution containing tungsten oxide and silver ions. In this sulfuric acid-copper sulfate electrolyte containing tungsten oxide, it is considered that tungsten oxide is formed in ultrafine particles from tungsten salt via tungstate ions (WO ₄ ^2- or WO ₅ ^2-, etc.). .

When copper electrodeposition is performed with a sulfuric acid-copper sulfate electrolyte containing tungsten oxide and silver ions having a low chloride ion concentration to form an electrolytic copper foil, tungsten oxide (WO ₃ , W ₂ O ₅ , WO ₂ etc.) or Each ultrafine particle of tungsten metal is adsorbed to the grain boundary, the growth of crystal nuclei is suppressed, the crystal grain is refined (low profile), and an electrolytic copper foil with high mechanical strength is formed in the normal state. The

Each ultrafine particle of tungsten oxide (WO ₃ , W ₂ O ₅ , WO _2, etc.) or metallic tungsten present in the crystal grain boundary of this electrolytic copper foil is not bonded or absorbed with the bulk copper crystal, It is considered that the ultrafine particles of tungsten oxide (WO ₃ , W ₂ O ₅ , WO ₂ etc.) or metallic tungsten remain as crystal grain boundaries.

Even when tungsten oxide or an electrolytic copper foil containing tungsten is heated at a high temperature of about 300 ° C., the ultrafine particles of tungsten oxide (WO ₃ , W ₂ O ₅ , WO _2, etc.) or metallic tungsten are separated by crystal grain boundaries. Thus, the copper fine crystals recrystallize due to heat to prevent the crystal grains from becoming coarse.

  Therefore, the electrolytic copper foil of the present invention has a high mechanical strength in the normal state, and the decrease in mechanical strength is small even after heating at a high temperature of about 300 ° C. It has excellent characteristics that are not found in the electrolytic copper foil produced by the electrolytic solution of the system.

  As described above, it is considered that a conventional organic additive added to a sulfuric acid-copper sulfate-based electrolytic solution forms a compound together with a metal element and chlorine in the electrolytic solution. In this case, the metal element is copper. Accordingly, a copper-organic additive-chlorine compound is formed in the sulfuric acid-copper sulfate electrolyte. When an electrolytic copper foil is formed by copper electrodeposition with this electrolytic solution, the copper-organic additive-chlorine compound is adsorbed to the crystal grain boundary, the growth of crystal nuclei is suppressed, the crystal grain is refined, and it is large in the normal state. An electrolytic copper foil with mechanical strength is formed.

  However, since this copper foil is a copper-organic additive-chlorine compound that exists at the grain boundary, copper is bound or absorbed by the bulk copper crystal, and the substance present at the grain boundary is the organic additive. Therefore, it is considered that these organic additives and chlorine decompose when exposed to a high temperature of about 300 ° C., resulting in a decrease in mechanical strength.

  The reason why the tensile strength is remarkably lowered when heated at a high temperature of about 300 ° C. is that the compound present at the grain boundary is an organic compound (organic additive) as described above, and the organic compound is about 300 ° C. It is considered that the mechanical strength decreases because it is easily decomposed by heating.

  In the techniques described in Patent Documents 1 to 4 and 6, electrolytic copper foils are manufactured using different organic compounds, but each is manufactured from a sulfuric acid-copper sulfate electrolytic solution containing an organic additive and chlorine. Since it is an organic compound component that is adsorbed to the crystal grain boundaries of the electrolytic copper foil, the mechanical strength is significantly reduced when the electrolytic copper foil is exposed to a high temperature of about 300 ° C. It is considered that all the compounds adsorbed on the crystal grain boundaries are organic compounds that are easily decomposed by heating at a high temperature of about 300 ° C.

On the other hand, the electrolytic copper foil of this embodiment is an electrolytic copper foil formed by electrolytic deposition from an electrolytic solution containing tungsten oxide and silver ions in a sulfuric acid-copper sulfate electrolytic solution having a low chloride ion concentration. is there.
As described above, as the tungsten component, tungsten oxide (WO ₃ , W ₂ O ₅ , WO ₂ , etc.) is obtained via a tungstate ion (WO ₄ ²⁻ or WO ₅ ²⁻ ) in a sulfuric acid-copper sulfate electrolyte. Or ultrafine particles of each of metallic tungsten are considered to be formed. When copper electrodeposition is performed with this electrolytic solution to form a copper alloy foil, each of the ultrafine particles of tungsten oxide (WO ₃ , W ₂ O ₅ , WO _2, etc.) or metallic tungsten remains in the form of ultrafine particles. To be adsorbed. As a result, growth of crystal nuclei is suppressed, crystal grains are refined, and an electrolytic copper foil having a large mechanical strength in a normal state is formed.

In such an electrolytic copper foil of this embodiment, since it can be made to take up to the upper limit of each uptake mechanism by taking in with two kinds of uptake mechanisms, the amount of uptake is increased more than a single uptake mechanism (heat resistance To improve the performance).
In the electrolytic copper foil of this embodiment, each ultrafine particle of tungsten oxide (WO ₃ , W ₂ O ₅ , WO _2, etc.) or metallic tungsten is taken into the crystal grain boundary by electrolytic deposition. These ultrafine particles have an effect of inhibiting recrystallization by affecting the surrounding crystal structure. Thereby, unlike the case of a copper-organic compound-chlorine compound, tungsten, which is a dispersion-precipitated metal, is not taken into the base material, but is added to a tungsten oxide (WO ₃ , W ₂ O ₅ , WO ₂ etc.) or a metal. It remains at the crystal grain boundary as it is with each ultrafine particle of tungsten, and the strength after heating is greatly improved.
In addition, in the electrolytic copper foil of the present embodiment, silver ions are co-deposited with copper as a base material and taken into the metal lattice. Due to the eutectoid, the lattice of the parent phase itself is different from pure copper, so that the energy required for recrystallization is made different. Thereby, since heat softening due to heating is unlikely to occur, strength reduction after heating is suppressed or strength is improved.
Due to the synergistic effect of the above action, the electrolytic copper foil of the present invention has high strength and high heat resistance that cannot be achieved by a single uptake mechanism.

For this reason, even when exposed to a high temperature of about 300 ° C., each ultrafine particle of tungsten oxide (WO ₃ , W ₂ O ₅ , WO ₂ etc.) or metallic tungsten stays at the crystal grain boundary, and the fine crystal of copper becomes Recrystallizes by heat, and works to prevent the crystal from becoming coarse.
Therefore, the normal mechanical strength is large, and even after heating at a high temperature of about 300 ° C., the decrease in mechanical strength is small, and the electrolysis produced by the sulfuric acid-copper sulfate-based electrolytic solution using conventional organic additives. It has excellent characteristics not found in copper foil.
The above embodiment is an example in which tungsten and silver are used. However, in the present invention, the same applies to the case of using other dispersed precipitation metal and eutectoid metal.

The electrolytic copper foil of the present invention can be suitably used for a flexible printed wiring board (FPC), a negative electrode current collector for a lithium ion secondary battery, and the like.
As described above, in the case of FPC, a certain strength or more is required after casting or heat laminating polyimide.
In the negative electrode current collector for a lithium ion secondary battery, when polyimide is used as the binder, the negative electrode is subjected to heat treatment in order to cure the polyimide. If the copper foil softens after heating and its strength becomes too small, the stress of expansion and contraction of the active material is applied to the copper foil during charging and discharging, and the copper foil may be deformed. In a more remarkable case, the copper foil may break. Accordingly, the copper foil for the negative electrode current collector needs to have a certain strength or more after heating.
Thus, in both cases of the flexible printed wiring board (FPC) and the negative electrode current collector for a lithium ion secondary battery, the polyimide is heated and cured at a temperature of about 300 ° C. Therefore, even if the copper foil is heated at a temperature of about 300 ° C. × 1H, a certain level of strength is required thereafter.
In the electrolytic copper foil of this invention, the standard of the pass level of these mechanical mechanical characteristics is as follows about each item. The tensile strength after heating at 180 ° C. is TS ≧ 310 MPa, the 0.2% proof stress is YS ≧ 200 MPa, and the elongation is El ≧ 1.5%. The tensile strength after heating at 300 ° C. × 1H is TS ≧ 280 MPa, the 0.2% proof stress is YS ≧ 150 MPa, and the elongation is El ≧ 2.5%. Further, the ratio (%) of the tensile strength to the normal tensile strength after heating at 300 ° C. × 1 H is 60% or more.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.
[Preparation of electrolyte]
A copper sulfate solution prepared to have a copper concentration of 50 to 120 g / L, a free sulfuric acid concentration of 30 to 150 g / L, and a chloride ion concentration of 3 mg / L or less was used as a basic solution.
Based on this basic solution, electrolytic solutions for preparing samples of Examples 1 to 10 and Comparative Examples 1 to 8 were prepared as described below.

Example 1
Tungsten (IV) disodium was dissolved in pure water and added to the basic bath as tungsten at 150 mg / L. Silver nitrate was added to the basic bath so as to be 10 mg / L as silver, and the electrolyte solution of Example 1 was obtained.

(Example 2)
Tungsten (IV) disodium was dissolved in pure water and added to the basic bath as tungsten at 30 mg / L. Silver nitrate was added to the basic bath so as to be 10 mg / L as silver, and the electrolyte solution of Example 2 was obtained.

(Example 3)
Disodium tungsten (IV) acid was dissolved in pure water and added to the basic bath as tungsten at 200 mg / L. Silver nitrate was added to the basic bath so as to be 10 mg / L as silver, and the electrolytic solution of Example 3 was obtained.

Example 4
Tungsten (IV) disodium was dissolved in pure water and added to the basic bath as tungsten at 150 mg / L. Silver nitrate was added to the basic bath at 1 mg / L as silver, and the electrolyte of Example 4 was obtained.

(Example 5)
Tungsten (IV) disodium was dissolved in pure water and added to the basic bath as tungsten at 150 mg / L. Silver nitrate was added to the basic bath so as to be 200 mg / L as silver, and the electrolyte solution of Example 5 was obtained.

(Example 6)
Tungsten (IV) disodium was dissolved in pure water and added to the basic bath as tungsten at 150 mg / L. Bismuth oxide was added to the basic bath as bismuth so as to give 500 mg / L, and the electrolyte solution of Example 6 was obtained.

(Example 7)
Tungsten (IV) disodium was dissolved in pure water and added to the basic bath as tungsten at 150 mg / L. Bismuth oxide was added to the basic bath as bismuth so as to be 50 mg / L to obtain an electrolyte solution of Example 7.

(Example 8)
Disodium molybdenum (IV) acid was dissolved in pure water and added to the basic bath as molybdenum at 20 mg / L. Silver nitrate was added to the basic bath to give 50 mg / L of silver, and the electrolyte solution of Example 8 was obtained.

( Reference Example 1 )
Titanium sulfate was dissolved in pure water and added to the basic bath so as to be 5 g / L as titanium. Silver nitrate was added to the basic bath at 30 mg / L as silver, and the electrolyte solution of Reference Example 1 was obtained.

(Example 9 )
Tellurium oxide was dissolved in hot concentrated sulfuric acid and added to the basic bath to give 10 g / L tellurium. Silver nitrate was added to the basic bath to give 30 mg / L of silver, and the electrolyte solution of Example 9 was obtained.

(Comparative Example 1)
Tungsten (IV) disodium was dissolved in pure water and added to the basic bath so that the concentration was 150 mg / L as tungsten. Thus, an electrolytic solution of Comparative Example 1 was obtained.

(Comparative Example 2)
Disodium molybdenum (IV) acid was dissolved in pure water and added to the basic bath so as to be 20 mg / L as molybdenum, to obtain an electrolytic solution of Comparative Example 2.

(Comparative Example 3)
Titanium sulfate was dissolved in pure water and added to the basic bath so that the titanium content was 5 g / L to obtain an electrolytic solution of Comparative Example 3.

(Comparative Example 4)
Tellurium oxide was dissolved in hot concentrated sulfuric acid and added to the basic bath so that the tellurium concentration was 10 g / L. Thus, an electrolytic solution of Comparative Example 4 was obtained.

(Comparative Example 5)
The electrolyte solution of Comparative Example 5 was prepared based on the example of Patent Document 6.

(Comparative Example 6)
Silver nitrate was added to the basic bath so as to be 200 mg / L as silver, and the electrolyte solution of Comparative Example 6 was obtained.

(Comparative Example 7)
Based on the example of Patent Document 7, an electrolytic solution of Comparative Example 7 was prepared.

(Comparative Example 8)
Bismuth oxide was added to the basic bath as bismuth at 500 mg / L to obtain an electrolyte solution of Comparative Example 8.

Electrodeposition was performed using the above electrolytic solutions under the following conditions to produce electrolytic copper foils each having a thickness of 12 μm.
Current density = 30-100 A / dm ²
Temperature = 30-70 ° C

  The tensile strength (TS) in the normal state of each obtained electrolytic copper foil and the tensile strength rust electrical conductivity after 300 degreeC x 1H heating were measured. In addition, the content of the dispersed precipitated metal and the content of the eutectoid metal in each electrolytic copper foil were measured. These results are shown in Table 1.

  Here, the tensile strength (tensile strength) in a normal state and the tensile strength (tensile strength) after heating at 300 ° C. × 1H of the foil-formed electrolytic copper foil were measured based on JISZ2241-1880. The conductivity was measured by a four-terminal method (current / voltage method) based on JIS-K6271. The results are shown in Table 1.

The metal content in the copper foil was determined by dissolving a certain mass of electrolytic copper foil with an acid and then analyzing W in the solution by ICP emission spectroscopy. The results are shown in Table 1 as the W content (ppm).
The standard of the pass level of the mechanical-mechanical property of the copper alloy foil in a present Example is as follows about each measurement item. The tensile strength (tensile strength) in the normal state is TS ≧ 500 MPa. The tensile strength (tensile strength) after heating at 300 ° C. × 1 H is TS ≧ 280 MPa. Further, the ratio (%) of the tensile strength to the normal tensile strength after heating at 300 ° C. × 1 H is 60% or more. The conductivity is 50% IACS or higher.

In comparison with the electrolytic copper foils of Comparative Examples 1 to 3, the electrolytic copper foils of Examples 1 to 7 had suppression or reduction in strength after heating due to the solid solution of the eutectoid metal. Moreover, the eutectoid metal contributed to the improvement of the electroconductivity of electrolytic copper foil, and especially Ag (Examples 1-5) had the effect of electrical conductivity maintenance (suppression of the electrical conductivity fall by alloying).
Moreover, the electrolytic copper foil of Example 8 compared with the electrolytic copper foil of the comparative example 2, even if it took in the same Mo as a metal oxide to about the same extent, the strength and electrical conductivity after a heating similar to the above Both were excellent . It was similar in comparison to the electrolytic copper foil of Comparative Example 4 and the electrolytic copper foil of the real施例9.

  In comparison between the electrolytic copper foil of Example 1 and the electrolytic copper foil of Comparative Example 7 (the electrolytic copper foil of the Example of Patent Document 7), the normal strength improvement due to the dispersed precipitated metal found in Example 1 is Comparative Example 7. It was not obtained. Further, in Comparative Example 6 in which the Ag amount in Comparative Example 7 was simply increased, no improvement in strength was obtained. This was the same in the comparison between the electrolytic copper foil of Example 6 and the electrolytic copper foil of Comparative Example 8 in which Bi was co-deposited.

  In comparison between the electrolytic copper foil of Example 3 and the electrolytic copper foil of Comparative Example 5 (the electrolytic copper foil of Example of Patent Document 6), the metal incorporated as the metal oxide is different, but the one of Comparative Example 5 is oxidized. Since the product alone (two-component system), the three-component system of Example 3 had higher normal strength and higher strength after heating, and maintained high electrical conductivity.

13 X-ray source 14 Incident X-ray 15 Shutter 17 Monochromator 19 First pinhole 21 Second pinhole 23 Attenuator 25 Third pinhole 27 Sample 29 Transmitted X-ray 31 Scattered X-ray 33 Beam stopper 35 Detector

Claims (9)

metal or oxides thereof present as an oxide in the pH4 following acidic conditions, and, viewed including the metals of codeposition of copper,
The metal present as an oxide under acidic conditions of pH 4 or less is either W, Mo or Te;
An electrolytic copper foil containing 10 ppm or more of a metal present as an oxide or an oxide thereof under an acidic condition of pH 4 or less as a metal . The electrolytic copper foil according to claim 1, comprising 100 ppm or more of a metal that co-deposits with copper. Electrolytic copper foil according to claim 1 or 2 metal eutectoid and copper is either Ag or Bi Electrolytic copper foil according to any one of claims 1 to 3 tensile strength after 300 ° C. heat treatment is not less than 900 MPa. Electrolytic copper foil according to any one of claims 1-4 conductivity is 70% IACS or more. The electrolytic copper foil of any one of Claims 1-5 which does not contain an organic additive. The electrolysis according to any one of claims 1 to 6 , produced by using an electrolytic solution containing an aqueous copper sulfate solution, an aqueous solution of the metal salt of the metal, and a chloride ion of 3 mg / L or less. Copper foil. An electrolyte is prepared by adding hydrochloric acid or a water-soluble chlorine-containing compound to a mixed solution of an aqueous copper sulfate solution and an aqueous solution of the metal salt of the metal so as to have a chloride ion concentration of 3 mg / L or less. method of manufacturing an electrolytic copper foil according to any one of claims 1 to 7 for producing an electrolytic copper foil by electrolytic deposition using. The manufacturing method of the electrolytic copper foil of Claim 8 which manufactures an electrolytic copper foil, without using an organic additive.

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