JP2010037585A - Copper foil and copper foil manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide copper foil capable of securing adhesiveness to a resin base material or the like and a method of manufacturing the copper foil. <P>SOLUTION: The copper foil 1 is provided with a copper foil material 10 having a first recessed part 15 on one surface and a copper plated layer 20 provided on one surface to have a second recessed part 25 having average depth narrower than that of the first recessed part 15 at a position corresponding to the first recessed part 15. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a copper foil and a copper foil manufacturing method. In particular, the present invention relates to a copper foil used for a printed circuit board and the like, and a copper foil manufacturing method.

  The resin base material on which the copper film is formed is called Copper Clad Laminate (CCL). And as CCL for flexible printed circuit boards (FPC), 3 layers CCL which bonds a copper foil and a resin base material through an adhesive, and 2 which bonds a copper foil and a resin base material without using an adhesive Layer CCL and the like are known. The copper foil used for CCL is subjected to a roughening treatment on the surface of the copper foil for the purpose of improving the adhesion to the resin substrate.

  Conventionally, the rolled copper foil for printed wiring boards with which the copper plating layer is provided in the surface of the rolled copper foil which has an unevenness | corrugation is known (for example, refer patent document 1). The rolled copper foil for printed wiring board described in Patent Document 1 eliminates unevenness on the surface of the rolled copper foil by copper plating, so that current does not concentrate locally in the roughening treatment, so-called roughened bumps are rolled. It is uniformly formed on the copper foil surface. Thereby, according to the rolled copper foil for printed wiring boards of patent document 1, the dispersion | variation in the roughening bump formed on the surface of a rolled copper foil can be made small.

JP 2005-340635 A

  However, since the rolled copper foil for printed wiring boards described in Patent Document 1 has the unevenness on the surface of the rolled copper foil disappeared by copper plating, the surface roughness of the rolled copper foil is reduced, and the rolled copper foil and the resin base are reduced. Adhesion with the material may be reduced. Moreover, when a roughening process is given to rolled copper foil, the defect called a crater by which a plating layer is not formed in the recessed part of the rolled copper foil surface may generate | occur | produce. When the size of the crater is increased, air bubbles may remain between the rolled copper foil and the resin base material when the resin base material is attached to the rolled copper foil and / or applied.

  Therefore, the objective of this invention is providing the copper foil and copper foil manufacturing method which can ensure the adhesiveness to the resin base material etc.

  In order to achieve the above object, the present invention provides a copper foil material having a first recess on one surface and a second recess having an average depth smaller than the average depth of the first recess. And a copper foil provided with a copper plating layer provided on one surface at a position corresponding to the first recess.

  Moreover, the copper foil may be an electrolytic copper foil or a rolled copper foil. The first recess includes a first slope having a first tilt angle with respect to the surface of the copper foil material, and the second recess has a second tilt angle with respect to the surface of the copper foil material. The average value of the second inclination angle may be smaller than the average value of the first inclination angle. Further, the average value of the second inclination angle may be not less than 1 degree and not more than 10 degrees.

  The copper foil may have an average depth of the second recesses of 0.1 μm to 0.7 μm, and the copper plating layer has a thickness of 0.1 μm to 1 μm. It may be. Moreover, the roughening process layer provided on a copper plating layer is further provided, and the roughening process layer contains a some structure, the surface of the copper plating layer substantially horizontal on one surface, and at least one part 2nd. It may be formed on the surface of the recess. And the roughening process layer is formed from copper or a copper alloy, and may have surface roughness (Rz) of 0.5 micrometer or more and 3 micrometers or less.

  In order to achieve the above object, the present invention provides a copper foil material preparation step for preparing a copper foil material, and a copper plating step for forming a copper plating layer on the surface of the copper foil material with a current density less than the limit current density, and A copper foil manufacturing method is provided.

  Moreover, the said copper foil manufacturing method prepares the copper foil material which has a 1st recessed part in one surface, and a copper plating process is smaller than the average value of the depth of a 1st recessed part. You may form the copper plating layer which has the 2nd recessed part which has the average value of depth in the position corresponding to a 1st recessed part. Further comprising a roughening treatment step of forming a roughening treatment layer on the surface of the copper plating layer, the roughening treatment step is a first treatment step of electrolytic treatment at a current density equal to or higher than a limit current density, and after the first treatment step, And a second treatment step in which plating is performed at a current density less than the limit current density.

Moreover, as for the said copper foil manufacturing method, a copper plating process may form a copper plating layer with the current density of 5 A / dm < ² > or more and less than 30 A / dm < ² >. In the copper plating step, a copper plating layer may be formed using a plating solution containing an organic sulfur compound having a mercapto group, a surfactant, and chloride ions.

  In order to achieve the above object, the present invention provides a copper foil material having a first recess on one surface and a second recess on a surface corresponding to the first recess. And a first recessed portion includes a first slope having a first inclination angle with respect to the surface of the copper foil material, and the second recessed portion is directed to the surface of the copper foil material. A copper foil is provided that includes a second slope having a second slope angle, the average value of the second slope angles being less than the average value of the first slope angles.

  Moreover, as for the said copper foil, the copper plating layer may have thickness of 0.1 micrometer or more and 1 micrometer or less.

  In order to achieve the above object, the present invention provides a copper foil material having a first recess on one surface and a second recess having an average depth smaller than the average depth of the first recess. Is provided on one surface at a position corresponding to the first recess, and a copper foil provided with a copper plating layer having a thickness of 0.1 μm or more and 1 μm or less is provided.

  According to the copper foil and the copper foil manufacturing method according to the present invention, it is possible to provide a copper foil and a copper foil manufacturing method capable of ensuring adhesion to a resin substrate or the like.

[Embodiment]
FIG. 1 shows an outline of a cross section of a copper foil according to an embodiment of the present invention.

(Structure of copper foil 1)
The copper foil 1 according to the present embodiment is provided so as to cover the copper foil material 10 having the first recess 15 on one surface and the one surface, and the second position at a position corresponding to the first recess 15. The copper plating layer 20 which has the recessed part 25, and the roughening process layer 30 formed in the surface of the copper plating layer 20 are provided. That is, the copper foil 1 has a laminated structure formed including the copper foil material 10, the copper plating layer 20, and the roughening treatment layer 30. Although not shown, a nickel-cobalt alloy plating layer, a zinc plating layer, a chromate treatment layer, a roughening treatment layer 30 for the purpose of further improving the adhesion of the copper foil 1 to a predetermined resin base material, And a silane coupling process layer can be formed.

  The copper foil material 10 has a predetermined thickness and is formed including copper. Further, the copper foil material 10 has a plurality of first recesses 15 on one surface. Each of the plurality of first recesses 15 includes an inclined surface 15a formed with a predetermined angle as a first inclination angle with respect to the surface 10a of the copper foil material 10. In the present embodiment, the average value of the angles of the plurality of inclined surfaces 15a with respect to the surface 10a is represented by θa. Each of the plurality of first recesses 15 has a predetermined depth, and in this embodiment, the average value of the depths of the plurality of first recesses 15 is represented by Da.

  Moreover, the copper foil material 10 is formed from an electrolytic copper foil or a rolled copper foil. In the case of forming the copper foil 1 according to the present embodiment, when the purpose is to ensure the flatness of the surface of the copper foil material 10 and to impart excellent bendability to the copper foil 1, the copper foil material 10 can be formed from rolled copper foil. Moreover, the copper foil material 10 can also be formed from pure copper or a copper alloy material. In the present embodiment, when the copper foil material 10 is formed from pure copper, impurities inevitably contained in the pure copper are not excluded.

  The copper plating layer 20 is formed on one surface of the copper foil material 10 by filling each of the plurality of first recesses 15. The copper plating layer 20 has second recesses 25 at positions corresponding to the plurality of first recesses 15, that is, above the plurality of first recesses 15, respectively. Each of the plurality of second recesses 25 is formed with a predetermined angle as a second inclination angle with respect to the surface 10a of the copper foil material 10 (or the surface 20a of the copper plating layer 20). including.

  In the present embodiment, an average value of angles with respect to the surface 10a of the plurality of inclined surfaces 25a is represented as θb. The second recess 25 is formed with a depth shallower than the depth of the corresponding first recess 15. In this embodiment, the relationship between θa and θb is θa> θb, and the relationship between Da and Db is Da> Db. And in this Embodiment, while setting the value of (theta) b to the range which can be implemented, it sets to the range which is easy to suppress generation | occurrence | production of a crater. For example, θb is preferably in the range of 1 to 10 degrees. Each of the plurality of second recesses 25 has a predetermined depth, and the average value of the depths of the plurality of second recesses 25 is represented as Db in the present embodiment. And in this Embodiment, it is preferable that Db is 0.1 micrometer or more and 0.7 micrometer or less.

  The copper plating layer 20 is formed on the copper foil material 10 so that at least a part of the second recesses 25 has a significant depth. For example, the copper plating layer 20 is preferably formed on the copper foil material 10 with a thickness of 0.1 μm or more and 1 μm or less.

  The roughening treatment layer 30 is provided on the copper plating layer 20 by forming a plurality of structures 35 on the surface 20 a of the copper plating layer 20. The plurality of structures 35 include a surface of the copper plating layer 20 that is substantially horizontal to one surface of the copper foil material 10 and a surface of at least a portion of the second recess 25 (that is, the slope 25a of the second recess 25). Surface). The structure 35 may be formed on the boundary between the surface 20a and the inclined surface 25a. Each of the plurality of structures 35 is formed including copper by plating. The plurality of structures 35 are each formed with a bump shape. And the roughening process layer 30 which concerns on this Embodiment has a surface roughness (Rz) of 0.5 micrometer or more which can ensure adhesiveness with resin, and generation | occurrence | production of a void at the time of bonding with resin. Has a surface roughness (Rz) of 3 μm or less. In addition, when the roughening process layer 30 which concerns on this Embodiment considers the virtual line | wire which connected each front-end | tip of the some structure 35, the said line will have a significant uneven | corrugated shape.

(Details of first recess 15 and second recess 25)
FIG. 2 shows an outline of evaluation of the depths of the first recess and the second recess according to the embodiment of the present invention.

The depth of the first recess 15 included in the copper foil material 10 is represented by the distance from the surface 10 a of the copper foil material 10 to the bottom of the first recess 15. For example, in FIG. 2, the depth of one first recess 15 is represented by D _a1 , and the depth of another first recess 15 adjacent to one first recess 15 is represented by D _a2 . It is. Similarly, the depth of the second recess 25 included in the copper plating layer 20 is represented by the distance from the surface 20 a of the copper plating layer 20 to the bottom of the second recess 25. For example, the depth of one second recess 25 is represented by D _b1 , and the depth of another second recess 25 adjacent to one second recess 25 is represented by D _b2 . The average value Da of the depths of the plurality of first recesses 15 and the average value Db of the depths of the plurality of second recesses 25 are respectively measured by measuring the depths of a predetermined number of each recess, and the arithmetic average thereof. Can be obtained by calculating.

  FIG. 3 shows an outline of the evaluation of the slopes of the slopes of the first recess and the second recess according to the embodiment of the present invention.

The inclination with respect to the surface 10a of the inclined surface 15a of the 1st recessed part 15 which the copper foil material 10 has is represented by angle (theta) _a1 . For example, in FIG. 3, the slope of the slope 15 a of one first recess 15 is represented by θ _a1 , and the slope of the slope 15 a of the other first recess 15 adjacent to one first recess 15 is It is represented by θ _a2 . Similarly, the inclination of the inclined surface 25a of the second recess 25 with the copper plating layer 20 is represented by theta _b1. For example, the slope of the slope 25a of one second recess 25 is represented by _θb1 , and the slope of the slope 25a of another second recess 25 adjacent to the second recess 25 is _θb2 . Represented. Note that the average value θa of the slopes 15a of the plurality of first recesses 15 and the average value θb of the slopes 25a of the plurality of second recesses 25 are measured by measuring the slopes of the predetermined number of recesses, respectively. Thus, it can be obtained by calculating the arithmetic average.

(Method for producing copper foil 1)
FIG. 4 shows an example of the manufacturing process of the copper foil according to the embodiment of the present invention.

(Copper foil preparation process)
First, a copper foil material 1 made of an electrolytic copper foil or a rolled copper foil having a predetermined shape, a predetermined thickness, and a predetermined surface roughness and having a plurality of first recesses 15 on one surface is prepared (step 100). (Hereafter, step is abbreviated as “S”)).

(Electrolytic degreasing process)
Next, at least one surface of the copper foil material 1 is cleaned (S110). Specifically, the surface of the copper foil material 1 is cleaned by electrolytic degreasing. For example, the surface of the copper foil material 1 is electrolytically degreased by applying a cathode electrolytic degreasing to the surface of the copper foil material 1 using an alkali solution such as sodium hydroxide.

(Pickling process)
Next, pickling treatment is performed on the surface of the copper foil material 1 for the purpose of neutralizing the alkaline solution remaining on the surface of the copper foil material 1 and removing the oxide film on the surface of the copper foil material 1. (S120). For example, the surface of the copper foil material 1 is pickled by immersing the copper foil material 1 in an acidic aqueous solution such as sulfuric acid. A copper etching solution can also be used as the acidic aqueous solution.

(Copper plating process)
Next, an acidic copper plating bath mainly composed of copper sulfate and sulfuric acid is prepared. Then, the copper foil material 1 is immersed in the copper plating bath as a cathode. In this state, by supplying an electric current to the copper foil material 1 and performing electrolytic treatment on one surface of the copper foil material 1, the copper plating layer 20 is formed on the surface (S130). Specifically, a copper plating layer having a second recess 25 having an average depth smaller than the average depth of the first recess 15 at a position corresponding to the first recess 15 is formed.

The electrolytic treatment is performed using a copper plating bath having a predetermined liquid composition at a current density lower than the limit current density at a predetermined liquid temperature for a predetermined time. The copper plating layer 20 is formed to a thickness of 0.1 μm or more and 1 μm or less, for example. Moreover, the electrolytic treatment using a copper plating bath can be implemented under the following conditions as an example.
Copper sulfate pentahydrate: 20 g / dm ³ or more and 300 g / dm ³ or less Sulfuric acid: 10 g / dm ³ or more and 200 g / dm ³ or less Liquid temperature: 20 ° C. or more and 50 ° C. or less Plating current density: 5 A / dm ² or more and 30 A / dm Less than ² (less than the limit current density)
Plating time: 1 second to 20 seconds

  Moreover, in the electrolytic treatment for forming the copper plating layer 20, a predetermined additive can be added for the purpose of smoothing the surface of the copper plating layer 20. Examples of additives include organic sulfur compounds having mercapto groups such as chlorine, 3-mercapto-1-sulfonic acid or bis (3-sulfopropyl) disulfide, surfactants such as polyethylene glycol or polypropylene glycol, and chlorides. At least one substance selected from the group consisting of ions and the like can be used.

  Moreover, the various additives for copper plating used for manufacture of a printed wiring board etc. can also be used. As an additive for copper plating, for example, CU-BRITE TH-RIII (manufactured by Sugawara Eugelite), Top Lucina LS (manufactured by Okuno Pharmaceutical Co., Ltd.), Capper Grime CLX (manufactured by Meltex Co., Ltd.), Sulcup EUC (manufactured by Uemura Kogyo Co., Ltd.) ) Etc. can be used.

The plating current density is set to a current density less than the limit current density for the purpose of suppressing the degree of unevenness of the surface 20a of the copper plating layer 20. In addition, for the purpose of improving productivity, the plating current density is set to a value equal to or higher than a predetermined value, and the plating current density is set to a value equal to or lower than a predetermined value for the purpose of smoothing the surface of the copper plating layer 20. Set. As an example, the plating current density is set to 5 A / dm ² or more and less than 30 A / dm ² .

(Roughening treatment step: first treatment step)
Subsequently, a dendritic copper plating layer is formed on the copper plating layer 20 (S140). Specifically, an acidic copper plating bath containing copper sulfate and sulfuric acid as main components is prepared. And the copper foil material 10 which has the copper plating layer 20 is immersed in this copper plating bath. Next, using the copper foil material 10 as a cathode, a current having a current density equal to or higher than the limit current density of the copper plating bath is supplied to the copper foil material 10 at a predetermined liquid temperature. Thereby, a dendritic copper plating layer is formed on the copper plating layer 20. As an example, the dendritic copper plating layer has a height of about 0.2 μm to 1.0 μm and a width of about 0.2 μm to 0.5 μm.

For example, the following conditions can be used as the copper plating bath and the copper plating conditions in the case of forming the dendritic copper plating layer. In addition, when forming a dendritic copper plating layer, metal elements (such as molybdenum, iron, or cobalt) other than copper can be added, for example. When molybdenum is used as the metal element to be added, the cross-sectional shape of the dendritic copper plating layer to be formed is rounded, and the dendritic copper plating layer is abnormal in a specific portion of the copper plating layer 20. Growth can be suppressed.
Copper sulfate pentahydrate: 20 g / dm ^{3 to} 300 g / dm ³ or less Sulfuric acid: 10 g / dm ^{3 to} 200 g / dm ³ or less Liquid temperature: 20 ° C. to 50 ° C. Plating current density: 30 A / dm ^{2 to} 100 A / dm ² or less (over limit current density)
Plating time: 1 to 10 seconds

(Roughening treatment step: second treatment step)
Next, a bump-like copper plating layer is formed from the dendritic copper plating layer (S150). Specifically, an acidic copper plating bath containing copper sulfate and sulfuric acid as main components is prepared. And the copper foil material 10 which has a dendritic copper plating layer is immersed in this copper plating bath. Next, using the copper foil material 10 as a cathode, a current having a current density lower than the limit current density of the copper plating bath is supplied to the copper foil material 10 at a predetermined liquid temperature. As a result, a bump-shaped copper plating layer (cover plating) having a smooth surface is formed on the surface of the dendritic copper plating layer. Thus, the dendritic copper plating layer is coated with a copper plating layer having a predetermined thickness, and a bump-shaped copper plating layer is formed. A roughening treatment layer 30 according to the present embodiment is formed.

For example, the following conditions can be used as the copper plating bath and the copper plating conditions in forming the bumpy copper plating layer.
Copper sulfate pentahydrate: 20 g / dm ^{3 to} 300 g / dm ³ or less Sulfuric acid: 10 g / dm ^{3 to} 200 g / dm ³ or less Liquid temperature: 20 ° C. to 50 ° C. Plating current density: 1 A / dm ^{2 to} 20 A / dm ² or less (less than the limit current density)
Plating time: 1 second to 20 seconds

(Post-treatment plating process)
In the manufacturing method of the copper foil 1 according to the present embodiment, after the bump-shaped copper plating layer is provided, the post-treatment plating film is roughened with the purpose of providing the copper foil 1 with predetermined characteristics. Can be formed on top. First, a nickel plating layer (or nickel alloy plating layer) is formed on the roughening treatment layer 30 for the purpose of preventing diffusion of copper constituting the roughening treatment layer 30 and the like (S160).

  Next, for the purpose of improving the heat resistance of the copper foil 1, a zinc plating layer (or zinc alloy plating layer) is formed on the nickel plating layer (S170). Furthermore, for the purpose of improving the adhesion of the copper foil 1 to the resin substrate, a silane coupling treatment layer as a chemical conversion treatment film is formed on the galvanized layer (S180).

  Through the above steps, copper foil 1 according to the present embodiment is manufactured. The copper foil 1 according to the present embodiment can be applied to, for example, a printed wiring board, an electromagnetic wave shield for plasma display, an antenna provided in an IC card, and the like.

(Effect of embodiment)
According to the embodiment of the present invention, the copper plating layer 20 having a thin film thickness is formed on the copper foil material 10 and then subjected to the roughening treatment, whereby the surface roughness is small and the copper having high flexibility. The foil 1 can be provided. Thereby, according to the copper foil 1 which concerns on this Embodiment, while forming the very thin copper plating layer 20, only by forming the roughening process layer 30 on the surface, while ensuring the adhesiveness with respect to a resin base material, When the copper foil 1 is etched to form a fine wiring, it is possible to suppress the occurrence of undercuts under the fine wiring.

  That is, according to the embodiment of the present invention, for example, in a printed wiring board such as a flexible printed board (FPC) used for an electronic device that is required to be downsized, the wiring pitch made of copper wiring is reduced. Even if it exists, it can suppress that the bottom part of the refined | miniaturized copper wiring is removed by an etching. Moreover, when the roughening process is performed on the copper foil 1, the generation of craters on the surface of the copper foil 1 can be significantly suppressed, and void defects during CCL fabrication can be reduced.

[Example]
FIG. 5 shows an outline of a cross section of a copper foil according to an embodiment of the present invention.

  In Examples 1 to 8 of the present invention, after the copper plating layer 20 was applied to the predetermined copper foil material 10, the roughening treatment layer 30 was formed on the copper plating layer 20. In this case, in the part of the second recess 25 corresponding to the first recess 15 of the copper foil material 10, there was a portion where the roughened layer 30 was not formed on the surface of the second recess 25. The portion where the roughened layer 30 is not formed was designated as a crater 40. Here, the roughening treatment layer 30 according to the present embodiment is formed of a dendritic copper plating layer 36 and a bump-like copper plating layer 37.

In Example 1 of the present invention, a rolled copper foil having a thickness of 17 μm was used as the copper foil material 10. And the surface of this rolled copper foil was cleaned by performing an electrolytic degreasing process and a pickling process. The electrolytic degreasing treatment is performed by setting the temperature to 40 ° C. in an aqueous solution containing sodium hydroxide 40 g / dm ³ and sodium carbonate 20 g / dm ³ and setting the current density to 5 A / dm ² for 10 seconds. ,Carried out. The pickling treatment was performed for 5 seconds with an aqueous solution containing 150 g / dm ³ of sulfuric acid at a temperature of 25 ° C. After the pickling treatment, the copper foil material 10 was washed with running water.

Next, the copper plating layer 20 was formed on the surface of the copper foil material 10 by plating. Specifically, a copper plating layer 20 having a thickness of 0.11 μm was formed on the surface of the copper foil material 10. As the copper plating solution, an aqueous solution containing copper sulfate pentahydrate 180 g / dm ³ and sulfuric acid 100 g / dm ³ was used. The conditions for copper plating were that the temperature of the plating solution was set to 45 ° C., the plating current density was set to 20 A / dm ² , and the plating time was 2 seconds.

Next, the copper foil material 10 on which the copper plating layer 20 was formed was washed with water. Then, a plating bath containing copper sulfate pentahydrate 75 g / dm ³ , sulfuric acid 150 g / dm ³ , iron sulfate heptahydrate 20 g / dm ³ , and sodium molybdate 1 g / dm ³ was prepared. And while setting the liquid temperature of the said plating bath to 30 degreeC, setting a current density to 40 A / dm < ² > and performing the electrolytic treatment for 5 second to the copper plating layer 20, dendritics on the copper plating layer 20 are carried out. A copper-like plated layer 36 was formed.

Next, the copper foil material 10 on which the dendritic copper plating layer 36 was formed was washed with water. Then, a plating solution containing copper sulfate pentahydrate 150 g / dm ³ and sulfuric acid 100 g / dm ³ was prepared. The temperature of the plating solution is adjusted to 40 ° C., the current density is set to 10 A / dm ^2, and the electrolytic treatment for 10 seconds is applied to the dendritic copper plating layer 36, thereby removing the dendritic copper plating layer 36. A bumpy copper plating layer 37 was formed.

Subsequently, a plating solution containing nickel sulfate hexahydrate 300 g / dm ³ , nickel chloride 45 g / dm ³ , and boric acid 50 g / dm ³ was prepared. The temperature of this plating solution was set to 50 ° C., the current density was set to ^{2 A} / dm ^2, and the electrolytic treatment for 5 seconds was applied to the copper foil material 10 on which the bumpy copper plating layer 37 was formed. Thereby, a nickel plating layer of 10 μg / cm ² was formed on the bumpy copper plating layer 37.

Next, the copper foil material 10 on which the nickel plating layer was formed was washed with water. A plating solution containing 90 g / dm ^{3 of} zinc sulfate and 70 g / dm ³ of sodium sulfate was prepared. The temperature of the plating solution was set to 30 ° C., the current density was set to 1.5 A / dm ^2, and the electrolytic treatment for 4 seconds was applied to the copper foil material 10 on which the nickel plating layer was formed. As a result, l. A 0 μg / cm ² galvanized layer was formed.

  Furthermore, the copper foil material 10 on which the galvanized layer was formed was washed with water. Then, the copper foil material 10 was dipped in a 10% 3-aminopropyltrimethoxysilane silane coupling solution at room temperature for 10 seconds, and then the copper foil material 10 was immediately dried at a temperature of 100 ° C. Thereby, the silane coupling process layer was formed on the zinc plating layer, and the copper foil 1 which concerns on Example 1 was obtained.

  The copper foil 1 according to Example 2 of the present invention was manufactured by the same method as that of the copper foil 1 according to Example 1, except that a 0.42 μm thick copper plating layer 20 was formed on the copper foil material 10. .

  The copper foil 1 according to Example 3 of the present invention was manufactured in the same manner as the copper foil 1 according to Example 1 except that a 0.71 μm thick copper plating layer 20 was formed on the copper foil material 10. .

In the copper foil 1 according to Example 4 of the present invention, the point of adding a predetermined additive to the copper plating solution used for forming the copper plating layer 20 and the current density for forming the copper plating layer 20 to 5 A / dm ² . It was manufactured by the same method as the copper foil 1 according to Example 1 except that the electrolytic treatment was performed for 8 seconds. The added additives are as follows. That is, copper sulfate pentahydrate 180 g / dm ³ , sulfuric acid 100 g / dm ³ , bis (3-sulfopropyl) disulfide 50 mg / dm ³ , polyethylene glycol 3000 200 mg / dm ³ , and chloride ion 50 mg / dm 3 An aqueous solution containing ³ was used as an additive.

The copper foil 1 which concerns on Example 5 of this invention sets the current density which forms the point which formed the copper plating layer 20 of 0.42 micrometer thickness on the copper foil material 10, and the copper plating layer 20 to 20 A / dm < ² >. The copper foil 1 was manufactured in the same manner as the copper foil 1 according to Example 4 except that the electrolytic treatment was performed for 7.5 seconds.

The copper foil 1 which concerns on Example 6 of this invention sets the current density which forms the point which formed the copper plating layer 20 of 0.71 micrometer thickness on the copper foil material 10, and the copper plating layer 20 to 30 A / dm < ² >. The copper foil 1 was manufactured in the same manner as the copper foil 1 according to Example 4 except that the electrolytic treatment was performed for 8.7 seconds.

The copper foil 1 which concerns on Example 7 of this invention was manufactured by the method similar to the copper foil 1 which concerns on Example 1 except the point which changed the current density at the time of forming a dendritic copper plating layer. That is, in Example 7, the current density when forming the dendritic copper plating layer was set to 45 A / dm ² and the plating time was set to 10 seconds.

  The copper foil 1 which concerns on Example 8 of this invention was manufactured by the method similar to the copper foil 1 which concerns on Example 1 except the point which formed the 1.2-micrometer-thick copper plating layer 20 on the copper foil material 10. FIG. .

(Comparative Example 1)
The copper foil which concerns on the comparative example 1 was manufactured by the method similar to Example 1 of this invention except the point which does not form a copper plating layer on the copper foil material 10. FIG.

(Comparative Example 2)
Copper foil of Comparative Example 2, except that the current density 35A / dm ² at the time of forming a copper plating layer on Dohakuzai 10 was prepared in the same manner as in Example 1 of the present invention.

  The characteristic was evaluated about each of the copper foil 1 which concerns on Examples 1-8 manufactured as mentioned above, and the copper foil which concerns on Comparative Examples 1-2.

  In addition, the thickness of the copper plating layer formed on the copper foil material 10 was calculated | required by processing a copper foil using Focused Ion Beam and observing the processed cross section with a scanning electron microscope. Moreover, the shape of the recessed part (the slope of a recessed part, and the inclination of a slope) of the surface of copper foil was evaluated using atomic force microscope (AFM SPM-9500J, Shimadzu Corp. make).

  Specifically, before and after the formation of the copper plating layer, the surface of the copper foil material and the copper plating layer was scanned with an AFM on a 250 μm × 250 μm region, and the average value of the depths of the recesses in the scanned region (Da And Db) and average values (θa and θb) of the angles of the inclined surfaces of the recesses with respect to the surface of the copper foil were measured. That is, Da and Db, and θa and θb were calculated in the same manner as described in FIGS. 2 and 3 of the embodiment of the present invention. In Examples 1 to 8 and Comparative Examples 1 and 2, the depth of the recess and the slope of each of the 100 recesses on the surface of the copper foil material and the 100 recesses on the surface of the copper plating layer were each. The angle was measured. And the average value of the depth of a recessed part and the average value of the angle of a slope were computed from the measurement result.

  Moreover, the surface roughness of the copper foil after forming a roughening process layer was evaluated by Rz by JISB0601-1994. The surface roughness was evaluated using a surface roughness measuring machine (SE500 surface roughness measuring machine, manufactured by Kosaka Laboratory).

  FIG. 6 shows an outline of a method for evaluating the bending characteristics of a copper foil.

  For the evaluation of the bending characteristics of the copper foil, a testing machine capable of examining the bending characteristics shown in FIG. 6 was used. The testing machine includes a vibration generating device 100 as a vibration generating source, a vibration adding unit 110 that transmits and applies the vibration generated by the vibration generating device 100 to the copper foil 1, and a conductor that fixes the copper foil 1 in a predetermined position. Fixed portions 130a to 130d and support portions 120a and 120b for fixing the vibration generating device 100 to a predetermined base are provided.

  Specifically, the vicinity of one end of the copper foil 1 is fixed by the conductor fixing portions 130a and 130c, and the vicinity of the other end of the copper foil 1 is fixed by the conductor fixing portions 130b and 130d. By bringing the vibration applying portion 110 into contact with the central portion of the copper foil 1, the copper foil 1 was held in an inverted W shape. In addition, each of the copper foils according to Examples 1 to 8 and Comparative Examples 1 to 2 is made into a tape-shaped sample having a width of 12.7 mm and a length of 200 mm, with the sampling direction of the test piece as the rolling direction, and the bending characteristics. evaluated. For the measurement of the bending characteristics, the number of bendings at the time of sample breakage when the radius of curvature was set to 2.5 mm, the stroke was set to 10 mm, and the bending speed was set to 1500 times / minute was evaluated as the bending life.

  Moreover, the crater density was calculated | required from the number of craters in the optical microscope photograph which image | photographed the 3 mm x 3 mm area | region of the copper foil surface which concerns on an Example and a comparative example using the optical microscope.

  Table 1 shows the results of evaluating the characteristics of the copper foils according to Examples and Comparative Examples using the above-described method.

  From the result of Table 1, in Examples 1-8, the crater density is reduced from the comparative example by forming the copper plating layer 20 on the surface of the copper foil material 10 and reducing Da and Db, and θa and θb. It was shown that a highly flexible copper foil with few defects such as craters can be formed.

  While the embodiments and examples of the present invention have been described above, the embodiments and examples described above do not limit the invention according to the claims. It should be noted that not all combinations of features described in the embodiments and examples are necessarily essential to the means for solving the problems of the invention.

It is sectional drawing of the copper foil which concerns on embodiment of this invention. It is a schematic diagram of the evaluation method of the depth of the 1st recessed part and 2nd recessed part which concerns on embodiment of this invention. It is an outline figure of the evaluation method of the slope of the slope of the 1st crevice and the slope of the 2nd crevice concerning an embodiment of the invention. It is a figure which shows the flow of the manufacturing process of the copper foil which concerns on embodiment of this invention. It is sectional drawing of the copper foil which concerns on the Example of this invention. It is a schematic diagram of the evaluation method of the bending characteristic of copper foil.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Copper foil 10 Copper foil material 10a Surface 15 1st recessed part 15a Slope 20 Copper plating layer 20a Surface 25 2nd recessed part 25a Slope 30 Roughening process layer 35 Structure 40 Crater 100 Vibration generator 110 Vibration addition part 120a, 120b Support part 130a, 130b, 130c, 130d Conductor fixing part

Claims (16)

A copper foil material having a first recess on one surface;
A copper plating layer provided on the one surface having a second recess having an average depth smaller than the average depth of the first recess at a position corresponding to the first recess. Copper foil provided with. The copper foil according to claim 1, wherein the copper foil material is an electrolytic copper foil or a rolled copper foil. The first recess includes a first inclined surface having a first inclination angle with respect to the surface of the copper foil material,
The second recess includes a second inclined surface having a second inclination angle with respect to the surface of the copper foil material,
The copper foil according to claim 2, wherein an average value of the second inclination angles is smaller than an average value of the first inclination angles. 4. The copper foil according to claim 3, wherein an average value of the second inclination angles is not less than 1 degree and not more than 10 degrees. 5. The copper foil according to claim 4, wherein an average value of the depth of the second recess is 0.1 μm or more and 0.7 μm or less. The copper foil according to claim 5, wherein the copper plating layer has a thickness of 0.1 μm or more and 1 μm or less. A roughening layer provided on the copper plating layer;
The roughening treatment layer includes a plurality of structures, and is formed on the surface of the copper plating layer substantially horizontal to the one surface and at least a part of the surface of the second recess. The described copper foil. The said roughening process layer is copper foil of Claim 7 formed from copper or a copper alloy, and having the surface roughness (Rz) of 0.5 micrometer or more and 3 micrometers or less. A copper foil material preparation step of preparing a copper foil material;
A copper foil manufacturing method comprising: a copper plating step of forming a copper plating layer on the surface of the copper foil material at a current density less than a limit current density. The copper foil material preparation step prepares the copper foil material having a first recess on one surface,
The copper plating step forms the copper plating layer having a second recess having an average depth smaller than an average depth of the first recess at a position corresponding to the first recess. The copper foil manufacturing method according to claim 9. Further comprising a roughening treatment step of forming a roughening treatment layer on the surface of the copper plating layer;
The roughening treatment step includes
A first treatment step for electrolytic treatment at a current density equal to or higher than the limit current density;
The copper foil manufacturing method according to claim 10, further comprising a second treatment step of performing a plating treatment at a current density lower than the limit current density after the first treatment step. The said copper plating process is a copper foil manufacturing method of Claim 11 which forms the said copper plating layer with the current density of 5 A / dm < ² > or more and less than 30 A / dm < ² >. The said copper plating process is a copper foil manufacturing method of Claim 12 which forms the said copper plating layer using the plating solution containing the organic sulfur compound which has a mercapto group, surfactant, and a chloride ion. A copper foil material having a first recess on one surface;
A copper plating layer provided on the one surface having a second recess at a position corresponding to the first recess,
The first recess includes a first inclined surface having a first inclination angle with respect to the surface of the copper foil material,
The second recess includes a second inclined surface having a second inclination angle with respect to the surface of the copper foil material,
The average value of the second inclination angle is a copper foil that is smaller than the average value of the first inclination angle. The copper foil according to claim 14, wherein the copper plating layer has a thickness of 0.1 μm or more and 1 μm or less. A copper foil material having a first recess on one surface;
A second recess having an average depth smaller than the average depth of the first recess is provided on the one surface at a position corresponding to the first recess; A copper foil provided with a copper plating layer having a thickness of 1 μm or more and 1 μm or less.

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