JP7172131B2 - Manufacturing method of high-purity electrolytic copper - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing high-purity electrolytic copper with less crystal lattice disturbance and less impurities between crystal lattices.

Main impurities contained in electrolytic copper are Ag, Fe, Ni, Al, etc., except for gas components (O, H, S, C, Cl, etc.). This is due to the co-deposition of Ag, which is a metal nobler than copper, together with copper in the electrodeposition mechanism of copper. In order to prevent the codeposition of Ag, a method of adding chloride ions to the electrolyte and removing the Ag ions in the electrolyte as silver chloride particles has been used. In order to obtain copper of higher purity, a method of carrying out electrolysis in two stages is known. For example, Patent Document 1 discloses a two-step process in which copper deposited by electrolysis of an aqueous solution of copper sulfate is recovered, and this copper is used as an anode and further electrolyzed at a low current density of 100 A/m ² or less in an aqueous solution of copper nitrate for purification. is described. However, the manufacturing method in which the electrolysis of the copper sulfate bath and the electrolysis of the copper nitrate bath are performed in two stages has the problem of being costly and troublesome.

Therefore, a method of reducing impurities by using a specific additive is known. For example, in Patent Document 2, mechanical properties and cathode properties are improved by adding a polyoxyethylene-based surfactant such as PEG (polyethylene glycol) to a copper sulfate electrolyte containing chloride ions, glue, and active sulfur components. A method for producing an electrolytic copper foil with improved adhesion is described. In addition, in Patent Document 3, by adding a smoothing agent such as PVA (polyvinyl alcohol) and a slime accelerator such as PEG, the copper surface is smooth and the content of impurities Ag and S is low. A method for producing copper is described. However, the content of Ag in the electrolytic copper deposited on the cathode cannot be sufficiently reduced only by adding PEG or PVA to the electrolyte.

In order to solve this problem, Ag A technology for producing high-purity electrolytic copper with remarkably low concentration and S concentration (Patent Document 4), or a main agent and IOB consisting of an ethylene oxide adduct having an IOB value of 1 to 2 in the organic conceptual diagram and an average molecular weight of 1,500 to 20,000. Technology for producing high-purity electrolytic copper with remarkably low Ag concentration and S concentration by using a stress relaxation agent such as PVA having a value of 2.0 to 9.5 and an average molecular weight of 6,000 to 150,000 (Patent Document 5) has been proposed by the applicant.

Japanese Patent Publication No. 08-000990 JP-A-2001-123289 Japanese Patent Application Laid-Open No. 2005-307343 JP 2017-043834 A JP 2017-066514 A

According to the techniques described in Patent Documents 4 and 5, high-purity electrolytic copper with remarkably low Ag concentration and S concentration (for example, 1 mass ppm or less) can be produced. On the other hand, in the production of electrolytic copper, it is important to reduce the concentration of impurities such as Ag and S contained in electrolytic copper and to reduce electrodeposition defects. Electrodeposition defects are voids in electrolytic copper, and when electrodeposition defects occur, the electrolyte is mixed in the voids, and when the electrolytic copper is melted and cast, the electrolyte components in these voids are mixed into the entire electrolytic copper. As a result, there is a problem that the purity after melting and casting is lowered. Moreover, it is preferable that the electrolytic copper does not warp, and in the production of electrolytic copper, electrolytic copper without warping is required.

In the present invention, it was found that occurrence of warping of electrolytic copper can be determined by using the average orientation difference in crystal grains (referred to as the GOS value) as an index. Conventionally, the warpage of electrolytic copper depends on visual observation, so that observation errors are unavoidable. The GOS value is also related to the impurity concentration of electrolytic copper. On the other hand, in the manufacturing methods of Patent Documents 4 and 5, it is not recognized that the crystal grain orientation of electrolytic copper should be adjusted (the misorientation within the crystal grain should be reduced). In the method for producing electrolytic copper, by reducing the orientation difference in the crystal grains, electrolytic copper does not warp, and electrolytic copper with reduced amounts of impurities such as Ag and S can be produced.

In the production of electrolytic copper, the present invention has solved the problem that the control of the misorientation of crystal grains has not been recognized conventionally. To provide a method for producing high-purity electrolytic copper with remarkably low concentration.

The present invention relates to a method for producing high-purity electrolytic copper, which solves the above problems by the following constitution.
[1] A first additive (A) containing an aromatic ring as a hydrophobic group and a polyoxyalkylene group as a hydrophilic group, a second additive (B) comprising polyvinyl alcohols, and a third additive comprising tetrazoles (C) is added to the copper electrolyte, the concentration of the first additive (A) is 10 mg/L or more and 500 mg/L or less, and the concentration of the second additive (B) is 1 mg/L or more and 100 mg/L or less. , the concentration of the third additive (C) is 0.01 mg/L or more to 30 mg/L or less, and the concentration ratio (B/A) of the second additive (B) to the first additive (A) is 0.01 mg/L or more and 30 mg/L or less. 1 or more to 0.8 or less, and the concentration ratio (C/A) of the third additive (C) to the first additive (A) is more than 0 to 0.7 or less, and the current density is 150 A/m ² or more . By controlling the bath temperature and performing copper electrolysis at 190 A / m ² or less , the Ag concentration is less than 0.2 mass ppm, the S concentration is less than 0.1 mass ppm, and the total impurity concentration is less than 0.2 mass ppm. A method for producing high-purity electrolytic copper, characterized by producing electrolytic copper having an area ratio of 10% or less of crystal grains having an average misorientation in crystal grains (referred to as a GOS value) exceeding 2.5°. .
[2] At a bath temperature of 30° C. or higher to 35° C. or lower, the Ag concentration is less than 0.15 mass ppm, the S concentration is less than 0.07 mass ppm, and the total impurity concentration is less than 0.2 mass ppm, and the crystal The method for producing high-purity electrolytic copper according to the above [1], wherein the area ratio of crystal grains having an intragranular average misorientation (GOS value) exceeding 2.5° is 10% or less.
[3] The concentration of the first additive (A) is 40 mg/L or more and 200 mg/L or less, the concentration of the second additive (B) is 10 mg/L or more and 50 mg/L or less, and the third additive. The concentration of (C) is 0.1 mg/L or more and 25 mg/L or less, and the concentration ratio (B/A) of the second additive (B) to the first additive (A) is 0.1 or more and 0.1 mg/L or more. 65 or less, the concentration ratio (C/A) of the third additive (C) to the first additive (A) is 0.001 or more to 0.5 or less, the Ag concentration is less than 0.1 mass ppm, the S concentration Less than 0.02 ppm by mass, a total impurity concentration of less than 0.1 ppm by mass, and an area ratio of crystal grains having an average misorientation (GOS value) exceeding 2.5° is 8% or less. The method for producing high-purity electrolytic copper according to the above [1] or [2] for producing electrolytic copper.
[4] The concentration of the second additive (B) is 10 mg/L or more and 50 mg/L or less, the concentration of the third additive (C) is 1 mg/L or more and 5 mg/L or less, and the first addition The concentration ratio (B/A) of the second additive (B) to the agent (A) is 0.13 or more and 0.4 or less, and the concentration ratio of the third additive (C) to the first additive (A) (C / A) is 0.005 or more to 0.10 or less, Ag concentration is less than 0.08 mass ppm, S concentration is less than 0.01 mass ppm, and total impurity concentration is less than 0.1 mass ppm , The high-purity electrolytic copper described in [1] or [2] above, which produces electrolytic copper in which the area ratio of crystal grains having an average orientation difference (GOS value) in the crystal grains exceeding 2.5 ° is 5% or less. manufacturing method.

According to the present invention, it is possible to provide a method for producing high-purity electrolytic copper with a small orientation difference in crystal grains and a remarkably low concentration of total impurities such as Ag and S.

The present invention will be specifically described below.
The production method of the present invention comprises a first additive (A) containing a hydrophobic aromatic ring and a hydrophilic polyoxyalkylene group, a second additive (B) comprising polyvinyl alcohols, and a tetrazole. The third additive (C) is added to the copper electrolyte, the concentration of the first additive (A) is 10 mg / L or more to 500 mg / L or less, and the concentration of the second additive (B) is 1 mg / L or more. 100 mg / L or less, the concentration of the third additive (C) is 0.01 mg / L or more to 30 mg / L or less, and the concentration ratio (B / A ) is from 0.1 to 0.8, and the concentration ratio (C/A) of the third additive (C) to the first additive (A) is from more than 0 to 0.7 or less, and the current density and the bath By controlling the temperature and performing copper electrolysis, the Ag concentration is less than 0.2 mass ppm, the S concentration is less than 0.1 mass ppm, and the total impurity concentration is less than 0.2 mass ppm. A method for producing high-purity electrolytic copper characterized by producing electrolytic copper having an area ratio of 10% or less of crystal grains having a difference (referred to as a GOS value) exceeding 2.5°.

The average misorientation within a grain is obtained by averaging the misorientation values within a grain between a pixel within the grain and all other pixels within the same grain. This value is called the GOS (Grain Orientation Spread) value of the crystal grain. The GOS value is described, for example, in "Proceedings of the Japan Society of Mechanical Engineers (Edition A) Vol. 71 No. 712 (2005-12) Paper No. 05-0367 (1722-1728)". In the crystal orientation analysis by the electron backscatter diffraction method, when the crystal grains to be measured have an orientation difference of 5 degrees or more between adjacent pixels, they are regarded as grain boundaries, and the area surrounded by the grain boundaries is one. Make it a crystal grain.

In the present invention, the average misorientation in crystal grains refers to this GOS value. When the GOS value is expressed by a formula, n is the number of pixels in the same crystal grain, i and j are the numbers assigned to different pixels in the same crystal grain (1≤i, j≤n), and the crystal orientation at pixel i and the crystal orientation difference obtained from the crystal orientation at pixel j is αij (i≠j), the GOS value can be expressed by the following equation [1].

The production method of the present invention produces electrolytic copper in which the area ratio of crystal grains having a GOS value exceeding 2.5° is 10% or less, preferably 8% or less, and more preferably 5% or less. The presence of impurities can be given as a reason why the area ratio of crystal grains having a GOS value exceeding 2.5° exceeds 10%. Impurities during electrodeposition are taken into grain boundaries and grains, causing misorientation within the grains and increasing the GOS value of the grains. If the area ratio of crystal grains with a GOS value of 2.5° or less is 90% or more, it is homogeneous electrolytic copper with little misorientation in the crystal grains, and there are no impurities taken into the crystal grain boundaries and crystal grains. This indicates that there is little electrolytic copper.

Also, the area ratio of crystal grains with a GOS value exceeding 2.5° can be used as an indicator of the occurrence of warpage in electrolytic copper. Specifically, when this area ratio is 20% or more, warping occurs during electrolysis, or when the electrolytic copper is peeled off from the cathode plate, no warping is observed, but warping occurs after 12 hours. . On the other hand, when the area ratio is 10% or less, the electrolytic copper does not warp during electrolysis, and the electrolytic copper does not warp even 12 hours after the electrolysis.

In the production method of the present invention, the area ratio of crystal grains with a GOS value exceeding 2.5 ° is 10% or less, and the Ag concentration is less than 0.2 mass ppm, the S concentration is less than 0.07 mass ppm, and all impurities Electrolytic copper is produced with a concentration of less than 0.2 mass ppm, preferably less than 0.01 mass ppm. The total impurity concentration is the total amount of impurities excluding gas components (O, F, S, C, Cl).

The GOS value of electrolytic copper is determined by adding a first additive containing an aromatic ring as a hydrophobic group and a polyoxyalkylene group as a hydrophilic group, a second additive comprising polyvinyl alcohols, and a third additive comprising tetrazoles. It is added to the copper electrolytic solution, each concentration of the first additive, the second additive, and the third additive is adjusted to a predetermined range, and the current density and bath temperature during copper electrolysis are adjusted to a predetermined range. It can be controlled by performing copper electrolysis. Copper electrolyte can be copper sulfate or copper nitrate.

The aromatic ring of the hydrophobic group of the first additive is, for example, a phenyl group or a naphthyl group, such as monophenyl, naphthyl, cumyl, alkylphenyl, styrenated phenyl, distyrenated phenyl, tristyrenated phenyl, and tribenzylphenyl. And so on. The polyoxyalkylene group of the hydrophilic group of the first additive is, for example, a polyoxyethylene group, a polyoxypropylene group, or the like, and may contain both a polyoxyethylene group and a polyoxypropylene group.

The aromatic ring is preferably a monophenyl group or a naphthyl group. The polyoxyalkylene group of the hydrophilic group includes, for example, a polyoxyethylene group, a polyoxypropylene group, and a mixture of a polyoxyethylene group and a polyoxypropylene group, and the polyoxyethylene group is particularly preferred.

Specific compounds of the first additive include, for example, polyoxyethylene monophenyl ether, polyoxyethylene methylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene naphthyl ether, polyoxyethylene Styrenated phenyl ether, polyoxyethylene distyrenated phenyl ether, polyoxyethylene tristyrenated phenyl ether, polyoxyethylene cumyl phenyl ether, polyoxypropylene monophenyl ether, polyoxypropylene methyl phenyl ether, polyoxypropylene octylphenyl ether, polyoxypropylene dodecyl phenyl ether, polyoxypropylene naphthyl ether, polyoxypropylene styrenated phenyl ether, polyoxypropylene distyrenated phenyl ether, polyoxypropylene tristyrenated phenyl ether, polyoxypropylene cumyl phenyl ether, etc. be.

The first additive preferably has a hydrophilic polyoxyalkylene group with a molar number of addition of 2 to 20, more preferably a number of moles of addition of 2 to 15. If the number of added moles is 2 or more, the additive is easily dissolved in the electrolytic solution. When the number of added moles is 20 or less, the additive does not adhere to the surface of the anode excessively, preventing the dissolution reaction of the anode from being excessively suppressed, thereby suppressing the generation of anode slime. , the yield of electrolytic copper can be further improved. Furthermore, when the number of added moles is 20 or less, dentrites are less likely to occur on the surface of the electrolytic copper deposited on the cathode, and the smoothness is improved. As a result, anode slime and S in the electrolytic solution are less likely to adhere to and remain on the surface of the electrolytic copper, thereby further improving the purity of the electrolytic copper. When the added mole number of the polyoxyalkylene group of the additive is 2 to 20, the dissolution of the anode proceeds moderately, so that the anode slime is less than when PEG or the like is used, and high-purity electrolytic copper can be obtained. can be done. Furthermore, the additive having a polyoxyalkylene group with 2 to 15 added moles can significantly reduce the S content of electrolytic copper.

Therefore, the first additive is preferably polyoxyalkylene monophenyl ether with 2 to 20 added moles, polyoxyalkylene naphthyl ether with 2 to 20 added moles, or the like.

The second additive polyvinyl alcohol preferably has a saponification rate of 70 to 99 mol %. When the saponification rate is 70 mol % or more, the effect of alleviating the internal strain of the cathode during electrodeposition is sufficient, and warping of the cathode during electrodeposition and the electrolytic copper after electrodeposition can be reliably suppressed. On the other hand, when the saponification rate is 99 mol % or less, the solubility is ensured, and it becomes easy to dissolve in the electrolytic solution.

Further, the second additive preferably has a weight average degree of polymerization (hereinafter referred to as "average degree of polymerization") of 200-2500. The basic structure of polyvinyl alcohol and its derivatives consists of a completely saponified type with hydroxyl groups and a partially saponified type with acetic acid groups. . The average degree of polymerization can be measured based on the JIS K 6726 polyvinyl alcohol test method.

A second additive having an average degree of polymerization of 200 or more is relatively easy to produce and is commonly used, so it is easy to obtain. Further, when the average degree of polymerization is 2500 or less, the effect of alleviating the internal strain of the cathode during electrodeposition is sufficient, and the cathode during electrodeposition and the electrolytic copper after electrodeposition are reliably prevented from warping. can be suppressed. Furthermore, when the average degree of polymerization is 2500 or less, the effect of suppressing electrodeposition is less likely to occur, and a decrease in the yield of electrolytic copper can be suppressed. Therefore, the average degree of polymerization of the second additive is more preferably 200-2000.

The tetrazoles of the third additive are tetrazoles and tetrazole derivatives. A tetrazole derivative can be used, for example, an alkyl derivative, an amino derivative, or a phenyl derivative of tetrazole. Specifically, 1H-tetrazole, 5-amino-1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole and the like can be used as the silver chlorine reducing agent.

The amount of the first additive to be added is preferably such that the concentration is 10 mg/L or more and 500 mg/L or less, and more preferably 40 mg/L or more and 200 mg/L or less. If the amount of the first additive added is less than 10 mg/L, it becomes difficult to control the area ratio of crystal grains with a GOS value exceeding 2.5 to 10% or less, and even if the amount exceeds 500 mg/L, the effect does not change much. do not have. In addition, if the amount of the first additive added is less than 10 mg/L, the electrolytic copper surface becomes rough and the purity is lowered. If it exceeds 500 mg/L, the effect of the additive becomes too large, the amount of slime generated from the anode increases, and the electrolytic copper tends to warp. In addition, dentrites are generated and the purity is lowered.

The amount of the second additive added is preferably an amount that provides a concentration of 1 mg/L or more and 100 mg/L or less, and more preferably an amount that provides a concentration of 10 mg/L or more and 50 mg/L or less. If the amount of the second additive added is less than 1 mg/L, it becomes difficult to control the area ratio of crystal grains with a GOS value exceeding 2.5 to 10% or less. There is a tendency for the area ratio of crystal grains exceeding 10% to exceed 10%.
In addition, if the amount of the second additive added is less than 1 mg/L, the electrolytic copper tends to warp. If it exceeds 100 mg/L, dentrites are likely to occur in the electrolytic copper, resulting in a decrease in purity.

The amount of the third additive to be added is preferably an amount that provides a concentration of 0.01 mg/L or more to 30 mg/L or less, and more preferably an amount that provides a concentration of 1 mg/L or more to 25 mg/L or less. If the amount of the third additive added is less than 0.01 mg/L, it becomes difficult to control the area ratio of crystal grains with a GOS value exceeding 2.5 to 10% or less. does not change.
In addition, if the amount of the third additive added is less than 0.01 mg/L, the effect of reducing the Ag concentration in the electrolytic copper is poor, and if the amount added exceeds 30 mg/L, dendrites are generated in the electrolytic copper. becomes easier and less pure.

The concentration ratio (B/A) of the second additive (B) to the first additive (A) is preferably from 0.1 to 0.8, more preferably from 0.13 to 0.65. If this concentration ratio is less than 0.1, it becomes difficult to control the area ratio of crystal grains with a GOS value exceeding 2.5 to 10% or less, and even if this concentration ratio exceeds 0.8, the effect does not change much. .

The concentration ratio (C/A) of the third additive (C) to the first additive (A) is preferably more than 0 and 0.7 or less, more preferably 0.001 or more and 0.5 or less. If this concentration ratio is less than 0.0001, it becomes difficult to control the area ratio of crystal grains with a GOS value exceeding 2.5 to 10% or less, and even if this concentration ratio exceeds 0.7, the effect does not change much. .

A first additive (A) containing a hydrophobic aromatic ring and a hydrophilic polyoxyalkylene group, a second additive (B) comprising polyvinyl alcohols, and a third additive (C) comprising tetrazoles. is added to the copper electrolyte, the concentration of the first additive (A) is 10 mg / L or more to 500 mg / L or less, the concentration of the second additive (B) is 1 mg / L or more to 100 mg / L or less, and the third The concentration of the additive (C) is 0.01 mg / L or more to 30 mg / L or less, and the concentration ratio (B / A) of the second additive (B) to the first additive (A) is 0.1 or more 0.8 or less, and the concentration ratio (C/A) of the third additive (C) to the first additive (A) is set to more than 0 to 0.7 or less, and the current density and bath temperature are controlled to perform copper electrolysis. By performing, the Ag concentration is less than 0.2 mass ppm, the S concentration is less than 0.1 mass ppm, and the total impurity concentration is less than 0.2 mass ppm, and the average orientation difference in the crystal grain (referred to as the GOS value) It is possible to produce electrolytic copper having an area ratio of 10% or less of crystal grains having a angle of more than 2.5°.

In addition, the current density is 150 A/m ² or more to 190 A/m ² or less, the bath temperature is 30° C. or more to 35° C. or less, the Ag concentration is less than 0.15 mass ppm, the S concentration is less than 0.07 mass ppm, and the total It is possible to produce electrolytic copper in which the impurity concentration is less than 0.2 ppm by mass and the area ratio of crystal grains having an average misorientation (GOS value) in crystal grains exceeding 2.5° is 10% or less.

Further, the concentration of the first additive (A) is 40 mg/L or more and 200 mg/L or less, the concentration of the second additive (B) is 10 mg/L or more and 50 mg/L or less, and the third additive ( The concentration of C) is 0.1 mg/L or more and 25 mg/L or less, and the concentration ratio (B/A) of the second additive (B) to the first additive (A) is 0.1 or more and 0.65. below, and the concentration ratio (C/A) of the third additive (C) to the first additive (A) is set to 0.001 to 0.5 or less, the Ag concentration is less than 0.1 ppm by mass, and the S concentration is 0.1 mass ppm. Electrolytic copper having a total impurity concentration of less than 0.02 mass ppm, a total impurity concentration of less than 0.1 mass ppm, and an area ratio of crystal grains having an average orientation difference (GOS value) exceeding 2.5° in the crystal grains of 8% or less can be manufactured.

Further, the concentration of the second additive (B) is 10 mg/L or more and 50 mg/L or less, the concentration of the third additive (C) is 1 mg/L or more and 5 mg/L or less, and the first additive The concentration ratio (B/A) of the second additive (B) to (A) is 0.13 or more and 0.4 or less, and the concentration ratio (B/A) of the third additive (C) to the first additive (A) C/A) is 0.005 or more to 0.10 or less, the Ag concentration is less than 0.08 mass ppm, the S concentration is less than 0.01 mass ppm, and the total impurity concentration is less than 0.1 mass ppm, It is possible to produce electrolytic copper in which the area ratio of crystal grains having an average orientation difference (GOS value) in crystal grains exceeding 2.5° is 5% or less.

In the production method of the present invention, the current density is preferably 150 A/m ² or more and 190 A/m ² or less, and the bath temperature is preferably 30° C. or more and 35° C. or less. When the bath temperature reaches 40° C., the concentration of Ag and the concentration of total impurities in the electrolytic copper tend to increase.
If the current density is too high or the bath temperature is too low, the balance between electrolysis and electrodeposition will be unbalanced, and passivation will occur on the anode surface, increasing the inter-electrode voltage. become unable. For example, in the case of a copper sulfate electrolyte, copper sulfate crystals form on the surface of the anode and cover the entire surface of the anode, increasing the inter-electrode voltage. On the other hand, if the current density is too low, the rate of electrodeposition slows down, resulting in a large amount of Ag eutectoid. The amount of co-deposited increases.

Specifically, in the production method of the present invention, when the current density is as low as about 140 A/m ² , the area ratio of crystal grains with a GOS value exceeding 2.5° in electrolytic copper becomes 15% or more, and the current Electrolysis becomes impossible when the density is as high as 200 A/m ² . Electrolysis also becomes impossible when the bath temperature is as low as about 20°C.

In the electrolytic copper produced by the production method of the present invention, the area ratio of crystal grains having an average orientation difference (GOS value) in the crystal grains exceeding 2.5° is 10% or less, and preferably the area ratio of the crystal grains is Since it is 8% or less, more preferably 5% or less, it is an electrolytic copper with no warpage. In addition, it is a high-purity electrolytic copper with few impurities taken into the crystal grain boundaries and crystal grains.

Furthermore, the electrolytic copper produced by the production method of the present invention has an Ag concentration of less than 0.2 mass ppm, an S concentration of less than 0.07 mass ppm, and a total impurity concentration of less than 0.2 mass ppm, preferably an Ag concentration of 0 0.17 mass ppm or less, an S concentration of 0.051 mass ppm or less, and a total impurity concentration of 0.194 mass ppm or less. ) can be widely used in fields that require a purity of at least

According to the production method of the present invention, the first additive (A) containing the aromatic ring of the hydrophobic group and the polyoxyalkylene group of the hydrophilic group, the second additive (B) made of polyvinyl alcohol, and the tetrazoles A third additive (C) consisting of By controlling the copper electrolysis, it is possible to produce a warp-free electrolytic copper in which the area ratio of crystal grains with a GOS value exceeding 2.5 ° is 10% or less, and the first additive (A) , the second additive (B), and the third additive (C) can be adjusted, and the process can be easily carried out without requiring a large-scale change of equipment.

In the production method of the present invention, the balance of electrodeposition is optimized, so that the anode dissolution is not excessively suppressed, the slime generation rate of the anode is reduced, preferably the slime generation rate is 25% or less, and the yield is increased. be able to.

Examples of the present invention are shown below together with comparative examples.
GOS values were measured as follows in Examples and Comparative Examples.
The electrodeposited copper was peeled off from the cathode substrate, the central 3 cm square was cut out, the cross section of this copper piece was processed by an ion milling method, and an EBSD (Electron Back Scatter Diffraction Patterns; OIM Data Collection manufactured by EDAX/TSL) device was attached. Using FE-SEM (JSM-7001FA manufactured by JEOL Ltd.), measurement is performed from the TD direction at a measurement step of 3 μm, and this measurement data and analysis software (EDAX / TSL OIM Data Analysis ver.5.2, the above formula [ The GOS value was analyzed using analysis software for calculating the GOS value based on [1]. A boundary with an orientation difference of 5° or more between adjacent pixels is regarded as a crystal grain boundary, and the orientation difference between pixels in the crystal grain and all pixels in other grains is calculated and the orientation difference is averaged. A GOS (Grain Orientation Spread) value was calculated using the
In addition, the GOS value of all crystal grains within a 3 cm square was calculated, and the area ratio of crystal grains with a GOS value exceeding 2.5° was obtained and shown in Table 1 as "area ratio [%] based on GOS value". .
In Table 1, the evaluation of "x" indicates that the electrolytic copper warped and dropped from the cathode substrate during the electrolytic test, and the electrolytic test could not be continued.

The S concentration, Ag concentration, and total impurity concentration excluding gas components of electrolytic copper were obtained by collecting a measurement sample from the central portion of the produced electrolytic copper and using a GD-MS device (VG-9000 manufactured by VG MICROTRACE). Ag, Al, As, Au, B, Ba, Be, Bi, C, Ca, Cd, Cl, Co, Cr, F, Fe, Ga, Ge, Hg, In, K, Li, Mg, Mn, Mo, Contents of Na, Nb, Ni, O, P, Pb, Pd, Pt, S, Sb, Se, Si, Sn, Te, Th, Ti, U, V, W, Zn and Zr were measured. Among these, all the components excluding gas components (O, F, S, C, Cl) were totaled to obtain the total amount of impurities.

Anode slime generation rate (%) was determined by the following formula [2].
Slime generation rate (%) = [{(weight before anode deposition - weight after anode deposition) - weight of cathode deposition} / (weight before anode deposition - weight after anode deposition)] x 100 ... [2 ]

Table 1 shows the slime generation rate obtained in each example and comparative example.
In Table 1, the evaluation of "x" indicates that the electrolytic copper warped and dropped from the cathode substrate during the electrolytic test, and the electrolytic test could not be continued.

Warpage of the electrolytic copper was determined by visual observation. "C" indicates that the electrolytic copper warped during the electrolysis and fell off the cathode substrate, or that the cathode substrate and the electrolytic copper did not adhere to the entire surface and were partially peeled off when the cathode was pulled up after the electrolysis test was completed. Judged.
Test No. in Table 1. Regarding 1 to 3, when the cathode pulled up after the completion of the electrolysis was visually observed, the cathode substrate and the electrolytic copper were partially peeled off. For Nos. 25 and 26, the electrolytic copper was warped and dropped from the cathode substrate during the electrolytic test, so it was judged as "C".
In the case where the cathode substrate and the electrolytic copper were in close contact with each other over the entire surface, the electrolytic copper was peeled off from the cathode substrate and placed on a table with the peeled surface facing downward. Electrolytic copper immediately after standing is flat. Within 12 hours after that, the electrolytic copper changed from a flat state to a warped shape was rated as "B", and when there was no change, it was rated as "A".

As a copper electrolyte, a copper sulfate solution having a sulfuric acid concentration of 50 g/L, a copper sulfate pentahydrate concentration of 197 g/L, and a chloride ion concentration of 50 mg/L was used. The following compounds were used as the first additive (additive A), the second additive (additive B), and the third additive (additive C). added.
<First additive A>
A-1: Polyoxyethylene monophenyl ether with 5 additional moles of ethylene oxide (manufactured by Nippon Nyukazai Co., Ltd., PgG-55)
A-2: Polyoxyethylene naphthyl ether with 10 moles of ethylene oxide added (Daiichi Kogyo Seiyaku Co., Ltd., Noigen EN-10)
A-3: Polyethylene glycol with an average molecular weight of 1500 (manufactured by Kanto Kagaku)
<Second additive B>
B-1: Polyvinyl alcohol with a saponification rate of 98.5 mol% and an average degree of polymerization of 500 (manufactured by Nippon Synthetic Chemical Industry, Gosenol NL-05)
B-2: Polyvinyl alcohol with a saponification rate of 99 mol% and an average degree of polymerization of 1200 (manufactured by Nippon Synthetic Chemical Industry, Gosenol NL-11)
B-3: Carboxy-modified polyvinyl alcohol with a saponification rate of 85 mol% and an average degree of polymerization of 250 (SD-1000 manufactured by Kuraray Co., Ltd.)
B-4: Polyvinyl alcohol with a saponification rate of 94.5 mol% and an average degree of polymerization of 3300 (JM-33 manufactured by Japan Vinyl Acetate & Poval Co., Ltd.)
<Third Additive C>
C-1: 1H-tetrazole (manufactured by Tokyo Chemical Industry Co., Ltd.)
C-2: 5-amino-1H-tetrazole (Tokyo Chemical Industry Co., Ltd.)
C-3: 5-methyl-1H-tetrazole (Tokyo Chemical Industry Co., Ltd.)

Electrolytic copper of 99.99% by mass (4N) was used for the anode, and an anode bag was used to prevent the slime generated from the anode from being taken into the cathode. A SUS316 plate was used as the cathode, and edge masking (Snapjaws™, manufactured by Material Eco-Refining Co., Ltd.) was used to prevent current from concentrating on the edge of the electrode. In addition, a preliminary test was performed in advance, the consumption rate of each additive was calculated, an additive replenishing solution was prepared, and the current density was set to 140 to 200 A / m ^2. Copper electrolysis was carried out for 7 days at a bath temperature of 20 to 40° C. while constantly removing particles and the like from the electrolytic solution with a filter having a filtration accuracy of 0.5 μm. Additives A, B, and C were measured every 48 hours. Additives A and B were measured using an ODS column with a UV detector on HPLC, and Additive C was measured using a GPC column with a corona charge detector on HPLC and varied more than 20% from the initial concentration. The additive concentration was corrected so that Tables 1 and 2 show the results of copper electrolysis.

As shown in Tables 1 and 2, all of the samples Nos. 1 to 4 that do not use the second additive (B) to the third additive (C) have a GOS value exceeding 2.5°. Since the ratio is 20% or more, the electrolytic copper warps during the electrolysis, and the crystal homogeneity is low. Also, in sample No. 7, in which the first additive (A) is polyethylene glycol, since the area ratio is 20% or more, the electrolytic copper warps and the crystal homogeneity is low. 07 ppm by weight and most have a total impurity concentration above 0.2 ppm by weight.
Sample No. 2 in which the second additive (B) is polyvinyl alcohol having an average degree of polymerization of 3300. In No. 8, since the average degree of polymerization is high, the effect of relieving internal stress strain is low, and since the area ratio exceeds 10%, the electrolytic copper warps and the crystal homogeneity is low.
In addition, sample No. 9 with a small amount of the second additive (B) and sample No. 10 with an excessively large amount of the second additive (B) both have the area ratio exceeding 10%. Warping of the electrolytic copper occurs, the crystal homogeneity is low, the S concentration exceeds 0.07 mass ppm, and the total impurity concentration exceeds 0.2 mass ppm.
Samples No. 5 and 6 do not contain the third additive (C), so the area ratio of crystal grains with a GOS value exceeding 2.5° is 10% or less, but close to the reference value of 10%. Moreover, the S concentration exceeds 0.07 mass ppm, and the total impurity concentration exceeds 0.2 mass ppm.

Samples Nos. 11 to 23 and 27 (Examples of the present invention) all have the above area ratios of 10% or less, and the electrolytic copper does not warp even during electrolysis and has high crystal homogeneity. Furthermore, it is high-purity electrolytic copper having an Ag concentration of 0.17 mass ppm or less, an S concentration of 0.051 mass ppm or less, and a total impurity concentration of 0.194 mass ppm or less. Further, the slime generation rate was 30% or less for all samples, and sample Nos. 21 to 23 and 27 were 20% or less.
In addition, sample no. In No. 27, the bath temperature of the electrolytic solution is relatively high at 40° C., so the Ag content exceeds 0.15 ppm by mass.

On the other hand, sample No. 24 has a too low current density (140 A/m ² ), so the area ratio of crystal grains with a GOS value exceeding 2.5° exceeds 15%, and sample No. 25 has a high current density. (200 A/m ² ), the electrolytic copper warped and dropped from the cathode substrate during the electrolytic test, and the electrolytic test could not be continued. Also, in sample No. 26, the bath temperature of the electrolytic solution was too low (20° C.), so the electrolytic copper warped and dropped from the cathode substrate during the electrolytic test, and the electrolytic test could not be continued.

Claims (4)

A first additive (A) containing a hydrophobic aromatic ring and a hydrophilic polyoxyalkylene group, a second additive (B) comprising polyvinyl alcohols, and a third additive (C) comprising tetrazoles. is added to the copper electrolyte, the concentration of the first additive (A) is 10 mg / L or more to 500 mg / L or less, the concentration of the second additive (B) is 1 mg / L or more to 100 mg / L or less, and the third The concentration of the additive (C) is 0.01 mg / L or more to 30 mg / L or less, and the concentration ratio (B / A) of the second additive (B) to the first additive (A) is 0.1 or more 0.8 or less, and the concentration ratio (C/A) of the third additive (C) to the first additive (A) is more than 0 to 0.7 or less, and the current density is 150 A / m ² or more and 190 A / m ² or less, and by performing copper electrolysis while controlling the bath temperature, the Ag concentration is less than 0.2 mass ppm, the S concentration is less than 0.1 mass ppm, and the total impurity concentration is less than 0.2 mass ppm, What is claimed is: 1. A method for producing high-purity electrolytic copper, wherein the area ratio of crystal grains having an average misorientation in crystal grains (referred to as a GOS value) exceeding 2.5° is 10% or less. The bath temperature is set to 30 ° C. or higher and 35 ° C. or lower, the Ag concentration is less than 0.15 mass ppm, the S concentration is less than 0.07 mass ppm, and the total impurity concentration is less than 0.2 mass ppm, and the grain average 2. The method for producing high-purity electrolytic copper according to claim 1, wherein the area ratio of crystal grains having a misorientation (GOS value) exceeding 2.5° is 10% or less. The concentration of the first additive (A) is 40 mg/L or more and 200 mg/L or less, the concentration of the second additive (B) is 10 mg/L or more and 50 mg/L or less, and the third additive (C). concentration of 0.1 mg / L or more to 25 mg / L or less, and the concentration ratio (B / A) of the second additive (B) to the first additive (A) is 0.1 or more to 0.65 or less, And the concentration ratio (C/A) of the third additive (C) to the first additive (A) is 0.001 to 0.5 or less, the Ag concentration is less than 0.1 ppm by mass, and the S concentration is 0.02 mass ppm, the total impurity concentration is less than 0.1 ppm by mass, and the crystal grains having an average orientation difference (GOS value) in the crystal grains exceeding 2.5° are 8% or less in terms of area ratio. The method for producing high-purity electrolytic copper according to claim 1 or 2. The concentration of the second additive (B) is 10 mg / L or more to 50 mg / L or less, the concentration of the third additive (C) is 1 mg / L or more to 5 mg / L or less, and the first additive (A ) of the second additive (B) to 0.13 or more and 0.4 or less, and the concentration ratio of the third additive (C) to the first additive (A) (C/ A) is 0.005 or more to 0.10 or less, the Ag concentration is less than 0.08 mass ppm, the S concentration is less than 0.01 mass ppm, and the total impurity concentration is less than 0.1 mass ppm, and the crystal grain 3. The method for producing high-purity electrolytic copper according to claim 1 or 2, wherein the area ratio of crystal grains having an internal mean misorientation (GOS value) exceeding 2.5° is 5% or less.