JP2008285727A - Electrolytic copper foil with high tensile-strength, and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolytic copper foil which is not softened in a period while being stored at ordinary temperature after the foil production process of the copper foil has been finished and before the next manufacturing process starts, or by heat treatment to be conducted at about 200 to 300°C in the next process, and maintains its high tensile-strength, and to provide a manufacturing method therefor. <P>SOLUTION: The electrolytic copper foil with high tensile-strength has a tensile strength of 400 N/mm<SP>2</SP>or higher which has been measured at 25°C after the foil production process of the copper foil has been finished and after the characteristics of the copper foil have been stabilized. A period of time necessary for the characteristics to become stable after the foil production process has been finished is preferably 48 hours or longer and further preferably is 72 hours or longer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a high tensile strength electrolytic copper foil that maintains a high tensile strength after foil production and a method for producing the same.

  Copper wiring is used for HDD suspensions, various connector parts, and the like. In these applications, high tensile strength is required in the usage environment.

  Copper foils are used for copper wiring parts such as HDD suspensions and various connector parts, but in recent years, high density mounting has progressed and thinner copper foils are required. There are two types of copper foil: rolled copper foil and electrolytic copper foil, but due to its manufacturing method, the productivity decreases as the thickness of the rolled copper foil decreases, but the cost increases as the thickness of the electrolytic copper foil increases. It becomes. Further, the electrolytic copper foil can be wider than the rolled copper foil. Therefore, the demand for electrolytic copper foil is increasing as a use for copper wiring parts such as HDD suspensions and various connector parts.

  However, the electrolytic copper foil currently produced has high tensile strength at the time of completion of foil production, but the copper foil after foil production is maintained at room temperature or heat treatment at about 200 to 300 ° C. in the subsequent process is performed immediately after the foil production. The high tensile strength cannot be maintained, and the high tensile strength sufficient for use in the above-described HDD suspension and various copper wiring portions cannot be maintained. This is because recrystallization occurs from a fine crystal state immediately after foil formation to a coarse crystal state having a low tensile strength and softens.

  The present invention is not softened even at room temperature storage from the time of completion of foil production to the next production process, or heat treatment at about 200 to 300 ° C. in the next process, which was difficult with the electrolytic copper foil of the conventional production method. It aims at providing the electrolytic copper foil which maintains high tensile strength, and its manufacturing method.

The electrolytic copper foil of the present invention is a high-strength electrolytic copper foil having a tensile strength of 400 N / mm ² or more measured at 25 ° C. after the completion of copper foil production and after the stabilization of the characteristics of the copper foil.

  Preferably, the time required for the characteristic stabilization is 48 hours or more, more preferably 72 hours or more after the completion of foil production.

The electrolytic copper foil of the present invention is a tensile strength measured at 25 ° C. after heat treatment at 300 ° C. for 1 hour after the copper foil is completed and the properties of the copper foil are stabilized. Is a high tensile strength electrolytic copper foil having 400 N / mm ² or more.

  Preferably, the time required for the above characteristics to stabilize is 48 hours or more, more preferably 72 hours or more after the completion of foil production.

The method for producing an electrolytic copper foil of the present invention comprises at least an average molecular weight of an electrolytic copper foil having a tensile strength of 400 N / mm ² or more measured at 25 ° C. after the completion of copper foil production and after stabilization of the characteristics of the copper foil. Is a method for producing a high tensile strength electrolytic copper foil in which a copper sulfate bath having a concentration of 100 or more organic compounds is 100 ppm or more.

The manufacturing method of the electrolytic copper foil of the present invention is as follows. After the copper foil is completed and the characteristics of the copper foil are stabilized, the copper foil is heat-treated at 300 ° C. for 1 hour, and at 25 ° C. after the heat treatment. In the method for producing a high tensile strength electrolytic copper foil, an electrolytic copper foil having a measured tensile strength of 400 N / mm ² or more is formed using a copper sulfate bath having a concentration of an organic compound having an average molecular weight of 100 or more and 100 ppm or more. is there.

  Preferably, the copper sulfate bath contains an organic sulfur-based compound, and is manufactured using a copper sulfate bath containing the organic compound having an average molecular weight of 100 or more at a concentration 100 times or more that of the organic sulfur-based compound. It is a manufacturing method of a tensile strength electrolytic copper foil.

According to the present invention, an electrolytic copper foil that maintains a high tensile strength of 400 N / mm ² or more during normal temperature storage from the completion of foil production to the next production process, or in heat treatment at about 200 to 300 ° C. in the subsequent process. Can be provided.

  In the present invention, the thickness of the electrolytic copper foil is preferably 1 μm or more and 300 μm or less. If the thickness of the copper foil is less than 1 μm, it will not be peeled off from the electrolytic drum at the time of manufacture, and even if it is peeled off, wrinkles will enter and it will not wind up well, which is not realistic. Moreover, in the thickness of 300 micrometers or more, it is because electrolytic foil is not preferable and is not realistic.

In the present invention, to produce an electrolytic copper foil, a copper sulfate plating bath is used as a copper plating bath. In the present invention, at least an organic compound having an average molecular weight of 100 or more is mixed in the copper sulfate plating solution as an additive. The addition amount of the organic compound having an average molecular weight of 100 or more is preferably 100 ppm or more. This concentration is much larger than the conventional amount of this kind additive.
In general, an organic sulfur compound is mixed in the electrolytic bath. In the electrolytic bath for producing the tensile strength copper foil of the present invention, the concentration of the organic compound having an average molecular weight of 100 or more increases the ratio to the concentration of the organic sulfur compound by 100 times or more.

  As described above, when the concentration of the organic compound having an average molecular weight of 100 or more is increased, the amount of impurities taken into the copper foil is increased. As a result, a large amount of impurities are dispersed in the crystal grain boundary, and crystal growth is suppressed. Therefore, even if it hold | maintains at normal temperature after completion of foil manufacture, it becomes possible to maintain a high tensile strength also after the heat processing at 200-300 degreeC in a post process.

Table 1 shows an example of the copper sulfate plating bath composition and plating conditions used in the present invention.
In Table 1, the composition and plating conditions of a conventional copper sulfate plating bath are also shown as comparative examples.

  At least one organic compound having an average molecular weight of 100 or more is added as an additive to the copper sulfate plating bath for producing the electrolytic copper foil. As an organic compound having at least an average molecular weight of 100 or more, glue, a polymer surfactant, a nitrogen-containing organic compound, or the like can be used. For organic compounds having an average molecular weight of less than 100, the desired additive effect cannot be expected. As the glue, commercially available ones can be used, but those having a low molecular weight are particularly preferred. Examples of the polymer surfactant include hydroxyethyl cellulose, polyethylene glycol, polypropylene glycol, polyethylene glycol dimethyl ether, and polyethylene oxide. Examples of the nitrogen-containing organic compound include polyethyleneimine and polyacrylic acid amide.

  The addition amount of the organic compound having an average molecular weight of 100 or more is preferably 100 ppm or more, more preferably 500 ppm or less. If the addition amount of the organic compound having an average molecular weight of 100 or more is less than 100 ppm, the amount of impurities taken into the copper foil that has been made is insufficient, and the desired high tensile strength foil cannot be obtained. On the other hand, if it exceeds 500 ppm, the amount added is excessive and normal foil production becomes difficult, and this is not preferable from the viewpoint of cost and stability as an electrolytic bath.

As an additive to the copper sulfate plating bath for producing the electrolytic copper foil, at least one organic compound having an average molecular weight of 100 or more and an organic sulfur compound are added.
Examples of the organic sulfur compound to be added include 3-mercapto-1-propanesulfonic acid and bis (3-sulfopropyl) disulfide. The addition amount of the organic compound having an average molecular weight of 100 or more is preferably 100 ppm or more, and is further added so that the concentration is 100 times or more that of the organic sulfur compound. Specifically, an organic sulfur compound is added in an amount of 1 to 5 ppm, and an organic compound having an average molecular weight of at least 100 is added in a range of 100 to 500 ppm. If the amount of the organic sulfur compound is less than 1 ppm, the amount becomes too small, making it difficult to produce a foil having the desired performance. Further, when the concentration exceeds 5 ppm, the concentration of the organic compound to be added exceeds 500 ppm, which makes it difficult to produce a normal foil, and is not preferable from the viewpoint of cost and liquid stability.

  EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited to these.

<Examples 1-5>
A copper sulfate plating solution (hereinafter referred to as an electrolytic solution) having the composition shown in Table 2 was passed through an activated carbon filter for cleaning treatment. Subsequently, the additive shown in Table 3 was added to this electrolyte solution so that it might become each density | concentration, and the electrolyte solution for foil manufacture of Examples 1-5 was adjusted. The additive used in Examples 1 to 5 is an organic sulfur compound, sodium 3-mercapto-1-propanesulfonate (MPS), and an organic compound having an average molecular weight of 100 or more is glue (PBF) (stock) Company Nippi). Using the electrolytic solution thus prepared, a copper foil was produced by electrolytic foil under the electrolysis conditions shown in Table 3, using a noble metal oxide-coated titanium electrode for the anode and a titanium rotating drum for the cathode. .

<Comparative Examples 1-5>
The electrolytic solution having the composition shown in Table 2 was passed through an activated carbon filter for cleaning treatment. Subsequently, the additive shown in Table 3 was added to this electrolyte so that it might become each density | concentration, and the electrolyte solution for foil manufacture of Comparative Examples 1-5 was adjusted. Using the electrolytic solution thus prepared, as in Examples 1 to 5, using a noble metal oxide-coated titanium electrode for the anode and a titanium rotating drum for the cathode, the electrolytic conditions shown in Table 3 were used. Copper foil was manufactured by electrolytic foil.

<Measurement of tensile strength and elongation>
In the electrolytic copper foils produced in Examples 1 to 5 and Comparative Examples 1 to 5, 24 hours, 48 hours, 72 hours, 96 hours, and 72 hours after completion of the foil production, in a nitrogen atmosphere at 300 ° C. The tensile strength and elongation at 25 ° C. after the time heat treatment were measured using a tensile tester based on JIS Z 2201: 1998. The results are shown in Tables 4 and 5.

<Evaluation of tensile strength>
As is apparent from Table 4, in Examples 1 to 5 and Comparative Examples 1 to 5, it can be considered that the recrystallization at room temperature and the accompanying decrease in the tensile strength are collected after 48 hours from the completion of the foil production. In Examples 1 to 5, it is produced by using a copper sulfate bath containing an organic compound (PBF) having an average molecular weight of 100 or more as an additive at a concentration 100 times or more that of an organic sulfur compound (MPS). An electrolytic copper foil that maintains a high tensile strength of 400 N / mm ² or more after the elapse of time has been obtained.
On the other hand, in Comparative Examples 1 to 5 manufactured using a copper sulfate bath containing an organic compound (PBF) having an average molecular weight of 100 or more as an additive at a concentration about 10 times that of the organic sulfur compound (MPS), Also, the tensile strength of 400 N / mm ² or more is maintained for about 48 hours from the completion of foil production, but after 48 hours, the tensile strength is 400 N / mm ² or less.

Table 5 shows a comparison between the tensile strength after 72 hours at room temperature and the tensile strength measured when the copper foil was naturally cooled after being heated at 300 ° C for 1 hour and reached 25 ° C. As is clear from Table 5, Examples 1 to 5 are slightly lower in tensile strength after heat treatment at 300 ° C. for 1 hour after 72 hours compared to the tensile strength for 72 hours from the completion of foil production. The tensile strength of 400 N / mm ² or more is maintained. In contrast, in Comparative Examples 1 to 5, the tensile strength is already 400 N / mm ² or less after 72 hours from the completion of the foil production, and when this copper foil is heated at 300 ° C. for 1 hour after 72 hours, the tensile strength is considerably lowered. ing.

<Evaluation of elongation>
As shown in Table 4, the elongation at normal temperature after foil production shows the same tendency in Examples 1 to 5 and Comparative Examples 1 to 5, but as shown in Table 5, 72 hours after the completion of foil production. Elongation and elongation after heating treatment at 300 ° C. for 1 hour after 72 hours have almost no change in Examples 1 to 5, but Comparative Examples 1 to 5 increase the elongation rate when heat treatment is performed at 300 ° C. for 1 hour after 72 hours. ing.
That is, since the elongation characteristics of the examples are stable even by heat treatment, it can be suitably used for products that require dimensional accuracy.

  As described above, the present invention can provide an electrolytic copper foil that exhibits a stable elongation characteristic even after foil formation and maintains high tensile strength, and can be suitably used as a copper wiring for HDD suspensions, various connector portions, and the like. Has an excellent effect.

Claims (7)

A high tensile strength electrolytic copper foil having a tensile strength of 400 N / mm ² or more measured at 25 ° C. after the completion of copper foil production and after the characteristics of the copper foil are stabilized.   The high-tensile-strength electrolytic copper foil according to claim 1, wherein the time required for stabilizing the characteristics is 48 hours or more after the completion of foil production. After completing the copper foil manufacturing and stabilizing the characteristics of the copper foil, the copper foil is heat treated at 300 ° C. for 1 hour, and the tensile strength measured at 25 ° C. after the heat treatment is 400 N / mm ² or more. High tensile strength electrolytic copper foil.   4. The high tensile strength electrolytic copper foil according to claim 3, wherein the time required for the characteristics to stabilize is 48 hours or more after the completion of foil production. An electrolytic copper foil having a tensile strength of 400 N / mm ² or more measured at 25 ° C. after the completion of copper foil production and after stabilization of the characteristics of the copper foil is at least 100 ppm in concentration of an organic compound having an average molecular weight of 100 or more. The manufacturing method of the high tensile strength electrolytic copper foil foil-made using the copper sulfate bath which is. After completing the copper foil manufacturing and stabilizing the characteristics of the copper foil, the copper foil is heat treated at 300 ° C. for 1 hour, and the tensile strength measured at 25 ° C. after the heat treatment is 400 N / mm ² or more. A method for producing a high tensile strength electrolytic copper foil, in which an electrolytic copper foil is made using at least a copper sulfate bath in which the concentration of an organic compound having an average molecular weight of 100 or more is 100 ppm or more.   The said copper sulfate bath contains an organic sulfur type compound, It manufactures using the copper sulfate bath which contains the said organic compound whose average molecular weight is 100 or more at a density | concentration 100 times or more of the said organic sulfur type compound. 6. A method for producing a high tensile strength electrolytic copper foil according to 6.