JP2005139546A - Blacking surface-treated copper foil, process for producing the blackening surface-treated copper foil and, using the blacking surface-treated copper foil, electromagnetic wave shielding conductive mesh - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-treated copper foil exhibiting black color which can be worked by the customary copper etching process, and a conductive mesh for PDP produced from such a surface-treated copper foil. <P>SOLUTION: For the production of this surface-treated copper foil, there is employed, for example, a process comprising subjecting a surface of a copper foil to pulse electrolysis in a cobalt plating solution containing cobalt sulfate (heptahydrate) at a fixed current density so as to form a blacking-treated surface and to form a rustproof treated layer and thereafter carrying out water washing and drying. The surface-treated copper foil provided with the blacking-treated surface obtained by the production process is free from the falling of powder, and has extremely satisfactory blackness. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a blackened surface-treated copper foil, a method for producing the blackened surface-treated copper foil, and an electromagnetic wave shielding metal mesh obtained using the blackened surface-treated copper foil.

  In the course of progress, the conductive mesh for shielding the plasma display panel has changed from a metalized fiber fabric to a conductive mesh. Several methods have been established for producing this conductive mesh. One of them is to manufacture by using a photolithographic etching method by laminating and bonding a surface-treated copper foil to a PET film. The other is a conductive mesh of a single surface-treated copper foil obtained by etching a surface-treated copper foil together with a supporting base material by a photolithographic etching method, and then peeling the supporting base material.

  Furthermore, due to the recent demand for power saving, development has been carried out with the target plasma generation signal voltage set to 200V to 50V level, and the circuit width of the conductive mesh has been made thinner to reduce the brightness associated with the voltage drop. Attempts have been made to reduce the coverage of the front glass panel with conductive mesh. Therefore, the thickness of the conductive mesh has been reduced to facilitate the etching process. One of them is to form a seed layer, which is the seed of electroplating, on the PET film by sputtering vapor deposition, and then to form a thin copper layer by electrolytic copper plating, etc., and to refine the mesh line width by photolithographic etching Conductive meshes have been manufactured.

  Regardless of which method is used to produce the conductive mesh, the conductive mesh itself is built into the front panel and visible from the surface through the front glass, so the surface processed into the conductive mesh. One side of the treated copper foil is treated black to enhance the brightness of the transmitted light. Conventionally, a blackening treatment or the like for forming a copper oxide layer for improving the adhesion of the multilayer printed wiring board to the resin layer of the inner layer circuit has been diverted to this treatment.

Technical Trends of PDP Materials Hitachi Chemical Technical Report No. 33 (1999-7) Japanese Patent Laid-Open No. 11-186785

  However, the above blackening process has a serious problem. That is, if a large amount of copper black oxide is applied to the surface of the copper foil, a good blackened surface with a strong black color can be obtained. However, the copper black oxide formed on the surface of the copper foil is more likely to fall off from the blackened surface as the amount of adhesion increases, and the so-called powder-off phenomenon tends to occur.

  Factors that cause the falling black oxide to mix into the useless parts or to disperse in the transparent adhesive layer during the clearing process to integrate with the front panel glass. It can be a friend.

  On the other hand, as blackening treatment that does not fall off like blackening treatment and can form a good black surface, general black nickel plating, nickel sulfide plating, cobalt plating, etc. have been studied. There has been a problem that etching cannot be performed from the blackened surface side in a normal copper etching process.

  Therefore, the present inventors have proposed a solution to the problem related to nickel plating in Japanese Patent Application No. 2003-045669. However, the problem relating to the surface-treated copper foil having a blackened surface using cobalt plating has not been solved. In particular, a copper foil provided with a black plating film of cobalt currently on the market has a problem that it is difficult to etch a cobalt layer using a copper etchant.

  Therefore, in the market, a surface-treated copper foil having a blackening treatment layer having a good black color and having a cobalt plating film that can be easily etched by a normal copper etching process, and manufactured with such a surface-treated copper foil An improved conductive mesh has been desired.

  Therefore, as a result of earnest research, the inventors of the present invention have come up with the idea that if a surface-treated copper foil is produced by the production method as shown below, a better blackened surface can be formed on the copper foil surface than ever before. is there. In addition, the surface-treated copper foil with a black cobalt plating layer obtained by the following manufacturing method can be easily etched with a copper etchant, and an electromagnetic shielding conductive mesh for the front panel of a high-quality plasma display. I realized that I could get it.

<Surface-treated copper foil obtained by the production method according to the present invention>
The surface-treated copper foil provided with the blackening treatment surface according to the present invention is basically a copper foil provided with a blackening treatment surface formed by a pulse electrolytic plating method using a cobalt sulfate bath. cobalt sulfate plating layer surface are weight thickness ^{200mg / m 2 ~400mg / m 2} , and the cross section height is said to black surface treated copper foil. "it is 200nm or less. Here, as a blackening treatment surface formed by the pulse electrolytic plating method, a very stable blackening treatment surface can be formed by adopting the pulse electrolytic plating method described later. And the case where a rust prevention treatment layer is not provided (henceforth "surface treatment copper foil 1") and the case where a rust prevention treatment layer is provided (henceforth "surface treatment copper foil 2") are included. . Therefore, the antirust treatment layer is not essential, but is necessary for ensuring long-term storage as a surface-treated copper foil. Hereinafter, the surface-treated copper foil according to the present invention will be described.

(First surface-treated copper foil)
FIG. 1 schematically shows a surface-treated copper foil 1a in which a cobalt sulfate plating layer 3 is provided on one surface of the copper foil layer 2 as a blackening treatment surface. The cobalt sulfate plating layer 3 here is used to mean a layer formed by a plating method using a cobalt sulfate solution.

As a first feature with the surface treated copper foil according to the present invention, the cobalt sulfate plating layer 3, With a weight thickness of ^{200mg / m 2 ~400mg / m 2} , the solubility of the copper etchant Excellent and sufficient blackening becomes possible. The cobalt layer of the copper foil provided with the black plating film using the conventional cobalt layer had a weight thickness of about 1000 mg / m ² and was very thick. As a result, because of the thickness, the dissolution rate by the copper etching solution slows down, and the element itself called cobalt accumulates in the copper etching solution at a high concentration, which causes the titer of the etching solution to decrease. . In addition, the conversion weight in this invention is a thing converted into a cobalt weight. The converted weight is obtained by dissolving the surface-treated copper foil in an acid solution, obtaining the amount of cobalt per unit area by plasma emission spectroscopy or the like, and converting it to the weight per 1 m ^{2 of the} surface-treated copper foil.

  It has also been found that whether or not the cobalt plating layer is easily dissolved in the copper etching solution is greatly influenced by the plating conditions when performing cobalt plating. That is, the cobalt plating film obtained when the method for producing a surface-treated copper foil according to the present invention described above is adopted has the best etching characteristics.

  The second feature of the surface-treated copper foil according to the present invention is that the surface shape of the blackened surface is not very rough, and the cross-sectional height of the blackened surface is 200 nm or less. This is the first feature. That is, it can be said to be a very smooth and glossy blackened surface. However, in order to avoid misunderstanding, it is natural that there is variation within the range of the normal manufacturing process, and the cross-sectional height at all positions is not necessarily 200 nm or less, Of course, there may be a cross-sectional height of more than 200 nm to reflect the variation in the manufacturing process. In order to measure the cross-sectional height of the blackened surface 2 of the surface-treated copper foil 1 according to the present invention, a SIM image of a cross-section prepared using a focused ion beam processing apparatus (FIB) is shown in FIG. FIG. 2 shows a blackened surface formed on the glossy surface of the electrolytic copper foil. 2 is an image observed from a direction having an angle of 60 ° with respect to the surface to be observed.

  As can be seen from FIG. 2, it is clear that the cross section of the blackened surface has certain irregularities. When monitoring such irregularities, it is common to use a stylus type surface roughness meter. It is. However, as can be seen from the scale of FIG. 2, it is considered that the surface roughness meter has irregularities at a level where accurate roughness measurement is impossible. Therefore, in the present invention, as a value corresponding to Rmax when measured with a surface roughness meter, the maximum difference between the peak portion and the valley portion in the field of view of the SIM observation image is set as the “section height”. The portion indicated by “d” in FIG. 2 is the sectional height of FIG. 2 and can be determined to be about 80 nm. Moreover, in FIG. 2, the blackening treatment surface 2 is formed with a very uniform thickness along the shape of the copper foil surface, and maintains a state of being completely in close contact with the underlying copper foil surface. There are no trouble spots such as the floatation surface 2 being lifted up, and there are no places where powder fall is predicted.

  On the other hand, when the blackened surface formed on the surface of the conventional copper foil is observed from the cross section in the same manner as described above, the results shown in FIGS. 3 and 4 are obtained. That is, it can be seen that the shape constituting the blackening treatment surface grows in a dendritic shape and is considerably protruded from the underlying copper foil. Therefore, when the cross-sectional height (d) at this time is measured, it can be understood that the surface in FIG. 3 is about 480 nm and the case in FIG. 4 is about 270 nm, which is a considerably rough surface. In addition, such a blackened surface having a dendritic shape can be said to be a surface where the dendritic part is easily broken and easily damaged, and it is natural that powder breakage occurs if the broken piece falls off. This is considered to be a cause of color unevenness when the blackened surface is visually observed.

  It can be understood that the surface-treated copper foil according to the present invention described above has a very smooth surface from the SIM cross-sectional observation image of FIG. However, although it is a glossy blackening treatment, it does not have a gloss that diffusely reflects the light received by the blackening treatment surface, and the glossy surface of the electrolytic copper foil and the rolled copper foil is subjected to blackening treatment However, the L value in the Lab color system is 27 or more. Here, as described as 27 or more, the upper limit is not particularly limited, but it seems that about 41 is the upper limit empirically.

  Whether or not the surface of the blackened surface is in a matte state is preferably expressed using glossiness rather than the Lab color system. However, the glossiness of the blackened surface according to the present invention should be classified according to the type of base on which the blackened surface is formed. One is that even when the blackened surface is a glossy surface of an electrolytic copper foil or a surface of a rolled copper foil, the glossy [Gs (60 °)] is 30 or less. It is preferable that When the glossiness is higher than 30, a so-called black shining state occurs and the metallic luster becomes conspicuous.

  Moreover, it is also preferable to provide a rust prevention treatment layer on the blackening treatment surface. This is because the long-term storage stability of the surface-treated copper foil according to the present invention can be ensured. In this rust-proofing layer, if it does not cause discoloration of the blackening-treated layer and can be easily dissolved by a copper etching solution, inorganic rust-proofing such as zinc and brass, benzotriazole, imidazole, etc. Any of organic rust prevention and the like can be used.

(Second surface-treated copper foil)
This surface-treated copper foil is obtained by forming a rust-proofing layer for ensuring long-term storage on the surface of the first surface-treated copper foil. The cross-sectional layer structure of the surface-treated copper foil 1b provided with the antirust treatment layer 4 on both surfaces of FIG. 5 is schematically illustrated. As long as the purpose is to prevent rust as copper foil only, organic rust prevention such as imidazole and benzotriazole, inorganic rust prevention using zinc alloy such as zinc or brass, etc. that are generally used can be widely used. It is. Moreover, although a rust prevention process layer should be provided in the opposite surface which provided the cobalt sulfate plating layer of the surface treatment copper foil which concerns on this invention at least, it does not interfere even if it provides in both surfaces.

  However, when the antirust treatment layers 4 are provided on both sides, these antirust treatment layers play a role of maintaining the appearance of the surface not subjected to the blackening treatment for a long period of time. It is particularly preferable to provide the rust prevention treatment layer 4 with a zinc-nickel alloy layer or a zinc-cobalt layer. These rust prevention treatment layers 4 are considered to function as a dissolution promoter when the cobalt sulfate plating layer 3 is dissolved by etching when used in combination with the cobalt sulfate plating layer 3. That is, the dissolution of the cobalt sulfate plating layer 3 occurs more quickly when the zinc sulfate plating layer 3 is provided alone than when the zinc sulfate alloy layer or the zinc-cobalt layer is provided.

    Furthermore, the cross-sectional layer structure of the surface treatment copper foil 1c provided with the antirust treatment layer 4 and the chromate treatment layer 5 on both surfaces is schematically shown in FIG. As can be seen from the comparison between FIG. 5 and FIG. 6, the difference from the surface-treated copper foil provided with these rust-proof treated layers 4 is only the point provided with the chromate treated layer 5, and other configurations are the same. is there.

  The chromate treatment layer 5 is formed on one side or both sides after the rust prevention treatment layer 4 made of zinc-nickel alloy or zinc-cobalt alloy is formed. The presence of the chromate treatment layer 5 significantly improves the oxidation resistance of the surface-treated copper foil, and effectively prevents cosmetic corrosion such as oxidation discoloration.

  The blackness of the surface-treated copper foil provided with the blackened surface described above is expressed as 1.0 or more (measurement conditions: Status T, Sampling aperture 1.5 × 2 mm, no polarizing filter) (experience) The upper limit is about 1.8). Conventionally, the black density of the blackened surface of the surface-treated copper foil used for the electromagnetic wave shielding mesh of the plasma display panel is about 1.0 or more when the blackened surface is directly observed (this invention) It is 1.30 to 1.67) when measured with a product available on the market such as a consumer, and it can be said that the black density is sufficient. The black density in the present invention is measured based on JIS B 9620 and JIS B 9622, and the above-described measurement conditions are adopted.

<Method for producing a surface-treated copper foil having a blackened surface>
(Basic manufacturing method of surface-treated copper foil with blackened surface)
The basic method for producing a surface-treated copper foil having a blackened surface in the present invention is “a method for producing a surface-treated copper foil having a blackened surface formed by cobalt sulfate plating, and pulse electrolysis is applied to cobalt sulfate plating. The manufacturing method of the surface treatment copper foil provided with the blackening process surface characterized by using a method. "

  In this manufacturing method, the blackened surface is formed on the surface of the copper foil by using cobalt sulfate plating, and at this time, the pulse electrolysis method is used. By adopting the pulse electrolysis method as described above, if the cobalt sulfate plating conditions are the same, a good blackened surface having a higher blackness than that obtained by normal electrolysis can be obtained. Here, the pulse electrolysis is an electrolysis operation performed by turning on / off the electrolysis current at regular time intervals. Hereinafter, although the manufacturing method of the surface treatment copper foil which concerns on this invention is demonstrated in detail, since it can divide roughly into two types of manufacturing methods by the presence or absence of a rust prevention process, it is "the manufacturing method 1 of a surface treatment copper foil. "And" Production method 2 of surface-treated copper foil "will be described separately.

(Method 1 for producing surface-treated copper foil)
The method for producing the surface-treated copper foil is different from the method 2 for producing the surface-treated copper foil described later in that it does not include a rust prevention treatment step. In this manufacturing method, it is desirable to employ a manufacturing method including the following steps.

  This production method is a production method employing a blackening treatment method that is suitable when there is no roughening treatment on the surface of the copper foil. A surface-treated copper foil having a blackened surface, characterized in that it is a method for producing a surface-treated copper foil having a blackened surface formed by cobalt sulfate plating, comprising the following steps a) and b): It is a manufacturing method of foil.

  Here, the copper foil to be plated with cobalt sulfate plating is not subjected to a roughening treatment, and this roughening treatment is applied in order to obtain good adhesion to the substrate to be bonded. It is intended for those that are intentionally roughened by a method such as attaching fine copper particles or attaching a copper oxide that appears black, and the bulk copper layer of the electrolytic copper foil It does not include rough surfaces that are naturally formed during deposition.

In the step a), a cobalt sulfate plating layer is formed on the surface of the copper foil described above. In the step a) at this time, cobalt sulfate (septahydrate) is contained in an amount of 10 g / l to 40 g / l on the surface of the copper foil that has not been roughened, and the pH is 4.0 or more. Using a cobalt sulfate plating solution having a temperature of 30 ° C. or less as a stirring bath, pulse electrolysis is performed at a current density of 4 A / dm ² or less to form a black cobalt sulfate plating layer. What is characteristic here is that the cobalt sulfate plating solution used for cobalt sulfate plating is electrolyzed while stirring.

  The cobalt sulfate concentration tends to create a better blackened state as the cobalt sulfate concentration is lower. However, when the cobalt sulfate (7 hydrate) in the cobalt sulfate plating solution is less than 10 g / l, the electrodeposition rate of the cobalt sulfate plating layer formed by using the stirring bath becomes slow, and the cobalt sulfate layer This tends to make the thickness non-uniform, resulting in a lack of industrial productivity. On the other hand, when cobalt sulfate (7 hydrate) exceeds 40 g / l, the formed cobalt sulfate plating layer is difficult to form dense irregularities, and as a result, it is not in a favorable blackened state.

The pulse electrolysis condition at this time is preferably such that the pulse ratio (θ = T _ON / (T _ON + T _OFF )) between the energization time (T _ON ) and the non-energization time (T _OFF ) is 0.75 or less. If this pulse ratio exceeds 0.75, the blackness becomes the same as that when continuous energization is applied, and the meaning of adopting the pulse electrolysis method is lost. On the other hand, the lower limit of the pulse ratio is not particularly specified, and the lower limit is not particularly limited, and the productivity is only inferior. Therefore, considering the productivity that can be operated from an industrial viewpoint, a pulse ratio of 0.05 is considered to be the lower limit.

  In addition, the solution pH of the cobalt sulfate plating solution at this time is 4.0 or more, and it is preferable to adjust the pH in the range of 4.5 to 5.5. In this range, a good black cobalt plating layer can be obtained with a good yield. For this pH adjustment, it is not preferable to add another electrolyte such as sodium hydroxide or potassium hydroxide in order to prevent the black color of the cobalt plating layer from changing to a metallic color.

  Therefore, the solution pH is stabilized in the range of 4.0 or more as a result by keeping the metal ion concentration in the solution constant. In order to stabilize the cobalt ion concentration in the solution in this way, a soluble cobalt electrode is used to dissolve and supply the electrodeposited cobalt ions, or the metal ion concentration is continuously monitored to obtain cobalt hydroxide. It is desirable to employ a technique for stabilizing the cobalt ion concentration by adding the material as appropriate.

  The cobalt sulfate plating solution at this time is preferably used at a liquid temperature of 30 ° C. or lower. At this time, the lower the liquid temperature, the better the blackened surface tends to be obtained. However, if the liquid temperature is set to 30 ° C. or lower, the method for producing the first surface-treated copper foil obtains a better blackened surface than when the surface of the copper foil without the roughening treatment is subjected to the blackening treatment. It becomes possible.

A current of 4 A / dm ² or less is used as the current density when electrolysis is performed. Within this range, even if the surface of the copper foil is not roughened, a good fine uneven cobalt sulfate plating layer having excellent adhesion to an organic agent or the like can be formed. Usually, in order to obtain an uneven black plating surface, a method of flowing an electrolytic current that enters an excessive burn plating region is employed. However, here, the smaller the current density used for electrolysis, the more stable blackening treatment tends to be possible. Therefore, a current density as small as possible should be adopted, but it can be determined that 0.5 A / dm ² is the lower limit value of the current density in consideration of industrial productivity. On the other hand, when the current density exceeds 4 A / dm ² , the blackening level of the blackened surface is deteriorated by the method for producing the first surface-treated copper foil. The blackening treatment surface formed in the above-described current density range does not cause the powder falling phenomenon.

  In the step b), the copper foil subjected to the above steps is washed with water and dried to obtain a surface-treated copper foil having a cobalt sulfate plating layer as a blackened surface. There is no particular limitation on the washing method and the drying method here, and it is possible to adopt a generally considered method.

(Method for producing second surface-treated copper foil)
In the case of the second surface-treated copper foil, a surface-treated copper foil having a cobalt sulfate plating layer as a blackened surface is produced in the same manner as in the above-described method for producing the first surface-treated copper foil. Layer formation is performed. Therefore, the manufacturing flow is as follows: “a) A black cobalt sulfate plating layer is formed on the surface of the copper foil. B) A rust preventive treatment layer is formed on both sides or one side of the copper foil on which the black cobalt sulfate plating layer is formed. C) Then, it is washed with water and dried. " That is, only the formation process of the antirust process layer increased in the manufacturing method of the 1st surface treatment copper foil.

  Therefore, only the formation process of the antirust treatment layer will be described here. A rust preventive layer is formed on both sides or one side of the copper foil on which the formation of the black cobalt sulfate plating layer has been completed. In the case of using conventionally known organic rust preventives such as imidazole and benzotriazole, and inorganic rust preventives such as commonly used zinc alloys such as zinc or brass, no special explanation is required and conventional methods are followed. Detailed explanation here is omitted.

Hereinafter, the case where the antirust treatment layer is formed by plating using a zinc-nickel alloy plating solution or a zinc-cobalt alloy plating solution will be described. First, the zinc-nickel alloy plating will be described. The zinc-nickel alloy plating solution used here is not particularly limited. For example, nickel sulfate is used to have a nickel concentration of 1 to 2.5 g / l, and zinc pyrophosphate is used to have a zinc concentration of 0.1 to 1 g. / L, potassium pyrophosphate 50-500 g / l, liquid temperature 20-50 ° C., pH 8-11, current density 0.3-10 A / dm ² , etc. are adopted.

Next, zinc-cobalt alloy plating will be described. The zinc-cobalt alloy plating solution used here is not particularly limited. For example, cobalt sulfate is used to have a cobalt concentration of 1 to 2.5 g / l, and zinc pyrophosphate is used to have a zinc concentration of 0.1 to 1 g. / L, potassium pyrophosphate 50-500 g / l, liquid temperature 20-50 ° C., pH 8-11, current density 0.3-10 A / dm ² , etc. are adopted. The anticorrosion treatment layer combining this zinc-cobalt alloy plating and the chromate treatment described later exhibits particularly excellent corrosion resistance.

  In the case of the second surface-treated copper foil, if a chromate layer is formed after forming a zinc-nickel alloy layer or a zinc-cobalt alloy layer on the surface of the copper foil, it is possible to obtain better corrosion resistance. It becomes. That is, a chromate treatment process may be provided after the formation of the above-mentioned rust prevention treatment layer. In this chromate treatment step, either a substitution treatment in which the chromate solution is brought into contact with the copper foil surface or an electrolytic chromate treatment in which a chromate film is formed by electrolysis in the chromate solution may be employed. is there. Also, the chromate solution used here can be in the range used in the usual method. And after that, the surface-treated copper foil provided with a blackening treatment surface is obtained by washing with water and drying.

  The surface-treated copper foil provided with the blackening treatment surface obtained by the production method according to the present invention described above has no powder falling off from the blackening treatment surface, and while having a very good black color, The blackened layer can be removed by a normal copper etching process. Therefore, it can be easily processed into an arbitrary shape by using a process for manufacturing a printed wiring board. Considering these things, it can be said that the electromagnetic wave shielding conductive mesh incorporated in the front panel of the plasma display panel is most suitable for use.

  Below, the surface-treated copper foil provided with the blackening process surface mentioned above is manufactured, and the result of having manufactured the electromagnetic wave shielding electroconductive mesh using the copper etching liquid is shown.

  In this example, blackening treatment is performed using a copper foil that has not been subjected to roughening treatment to produce a first surface-treated copper foil 1a shown in FIG. 1, and an electromagnetic shielding conductive mesh shape is experimentally tested by an etching method. The etching performance was confirmed.

  In this example, a copper foil having a nominal thickness of 15 μm obtained by electrolyzing a copper sulfate solution was used. The copper foil was immersed in this solution for 30 seconds using a dilute sulfuric acid solution having a sulfuric acid concentration of 150 g / l and a liquid temperature of 30 ° C. to clean the surface.

And the cobalt sulfate plating layer was formed on the rough surface of the said copper foil as a) process, without giving a roughening process to the single side | surface of the said copper foil. The cobalt sulfate plating layer is formed by using a cobalt sulfate plating solution adjusted to 20 g / l of cobalt sulfate (7 hydrate), pH of 5.5, and a liquid temperature of 27 ° C. as a stirring bath, 1 A / dm ² A black cobalt sulfate plating layer was formed by pulse electrolysis with a current density of 0.25 and a pulse ratio of 0.25 for a total energization time of 15 seconds. At this time, the adjustment of the cobalt ion concentration in the solution is not particularly performed. This is because it was considered that it was unnecessary to adjust the metal ion concentration because of the short-time electrolysis.

  As a process of b), the pure water is sufficiently showered and washed, and is kept in a drying furnace with an atmospheric temperature of 150 ° C. for 4 seconds from an electric heater to remove moisture, and a blackening treatment with a very good color tone. A surface-treated copper foil 1a having a surface was obtained. FIG. 7 shows a scanning electron microscope observation image of the blackened surface obtained here. In addition, in principle, a water washing step with pure water for 15 seconds is provided between the steps described above to prevent the solution from being brought into the pretreatment step.

The cobalt sulfate plating layer of the surface-treated copper foil provided with the blackened surface obtained as described above has a weight thickness of 340 mg / m ² , a cross-sectional height of 100 nm, and an L value in the Lab color system of 30. The glossiness [Gs (60 °)] was 19, and the black density was 1.3.

  Furthermore, the dry film used as an etching resist was bonded together on both surfaces of the said surface treatment copper foil. Then, only the dry film on the blackened surface side is overlaid with a test mask film for producing an electromagnetic shielding conductive mesh, and the mesh pitch is 200 μm, the mesh line width is 10 μm, and the mesh bias angle is 45 °. A conductive mesh pattern having a mesh electrode portion was exposed to ultraviolet rays. At this time, the entire surface of the etching resist layer on the opposite side was also exposed to ultraviolet rays so that it could not be removed by subsequent development. Then, it developed using the alkaline solution and formed the etching resist pattern.

  Then, using an iron chloride etchant that is a copper etchant, copper etching was performed from the blackened surface side, and then the etching resist layer was peeled off to produce an electromagnetic wave shielding conductive mesh. As a result, there was no etching residue and very good etching was performed. FIG. 8 shows an etching state of a test pattern (13 μm width circuit) for evaluating the etching property. As can be seen from FIG. 8, there is no etching residue and a beautiful circuit having an extremely excellent etching factor is obtained.

  In this embodiment, as shown in FIG. 2, a second surface-treated copper foil 1b having a zinc-nickel alloy layer as a rust-proofing layer is produced, and an electromagnetic shielding conductive mesh shape is produced experimentally by an etching method. The etching performance was confirmed. Therefore, since it is common with Example 1 until the blackening process layer by a cobalt sulfate plating layer is formed, only rust prevention process conditions are demonstrated.

Here, since the plating treatment using the zinc-nickel alloy plating solution was performed on both surfaces of the copper foil on which the formation of the black cobalt sulfate plating layer was completed on one surface of Example 1, the zinc-nickel alloy layers were formed on both surfaces. is there. The zinc-nickel alloy layer uses nickel sulfate, nickel concentration is 2.0 g / l, zinc pyrophosphate is used, zinc concentration is 0.5 g / l, potassium pyrophosphate 250 g / l, liquid temperature 35 ° C., pH 10, current Electrolysis was performed for 5 seconds under conditions of a density of 5 A / dm ² , and electrodeposited uniformly and smoothly on both surfaces.

  Then, the pure water was sufficiently showered and washed in the same manner as in Example 1, and was retained in a drying furnace at an atmospheric temperature of 150 ° C. for 4 seconds from an electric heater to remove moisture, and a black with a very good color tone. The surface-treated copper foil 1b provided with the chemical treatment surface was obtained. In principle, a water washing step with pure water for 15 seconds is provided between the above-described steps to prevent the solution from being brought into the pretreatment step. In addition, the scanning electron microscope observation image of the blackening process surface obtained here is the same state as FIG.

The cobalt sulfate plating layer of the surface-treated copper foil having the blackened surface obtained as described above has a weight thickness of 340 mg / m ² , a cross-sectional height of 95 nm, and an L value in the Lab color system of 32. The glossiness [Gs (60 °)] was 18, and the black density was 1.31.

  Moreover, the dry film used as an etching resist was bonded together on both surfaces of the said surface treatment copper foil, and the electroconductive mesh pattern was formed by the method similar to Example 1. FIG. As a result, there was no etching residue and very good etching was performed.

  In this embodiment, as shown in FIG. 3, a second surface-treated copper foil 1c having a zinc-nickel alloy layer and a chromate-treated layer as a rust-proof treated layer is produced, and an electromagnetic shielding conductive mesh shape is formed by an etching method. Manufactured experimentally to confirm the etching performance. Therefore, since it is common with Example 1 until the blackening process layer by a cobalt sulfate plating layer is formed, only rust prevention process conditions are demonstrated.

In the same manner as in Example 2, the rust-proofing layer was formed by forming a zinc-nickel alloy layer on both sides using a zinc-nickel alloy plating solution, followed by electrolytic chromate treatment on both sides. A chromate layer was formed on the alloy layer by electrolysis. The electrolysis conditions at this time were chromic acid 5.0 g / l, pH 11.5, liquid temperature 35 ° C., current density 8 A / dm ² , and electrolysis time 5 seconds.

  When the formation of the chromate layer is finished, the pure water is sufficiently showered and washed, and is kept in a drying furnace with an atmospheric temperature of 150 ° C. for 4 seconds from an electric heater to remove moisture, and a very good color tone. A surface-treated copper foil having a blackened surface was obtained. In addition, the scanning electron microscope observation image of the blackening process surface obtained here is the same state as FIG. Further, in principle, a water washing step with pure water for 15 seconds is provided between the above-described steps to prevent the solution from being brought into the pretreatment step.

The cobalt sulfate plating layer of the surface-treated copper foil having the blackened surface obtained as described above has a weight thickness of 340 mg / m ² , a cross-sectional height of 100 nm, and an L value in the Lab color system of 31. The glossiness [Gs (60 °)] was 18, and the black density was 1.29.

  Moreover, the dry film used as an etching resist was bonded together on both surfaces of the said surface treatment copper foil, and the electroconductive mesh pattern was formed by the method similar to Example 1. FIG. As a result, there was no etching residue and very good etching was performed.

  In this example, blackening treatment is performed using a copper foil that has not been subjected to roughening treatment to produce a first surface-treated copper foil 1b, and an electromagnetic shielding conductive mesh shape is experimentally produced by an etching method and etched. The performance was confirmed.

  In this example, a copper foil having a nominal thickness of 15 μm obtained by electrolyzing a copper sulfate solution was used. The copper foil was immersed in this solution for 30 seconds using a dilute sulfuric acid solution having a sulfuric acid concentration of 150 g / l and a liquid temperature of 30 ° C. to clean the surface.

And the cobalt sulfate plating layer was formed on the rough surface of the said copper foil as a) process, without giving a roughening process to the single side | surface of the said copper foil. The cobalt sulfate plating layer was formed by adjusting cobalt sulfate (7 hydrate) to 20 g / l, adjusting the pH to 5.5, and stirring the cobalt sulfate plating solution at a liquid temperature of 27 ° C. 2 A / dm ² A black cobalt sulfate plating layer was formed by electrolysis with a current density of 0.5 and a pulse ratio of 0.5 for a total energization time of 7 seconds. At this time, the adjustment of the cobalt ion concentration in the solution is not particularly performed. This is because it was considered that it was unnecessary to adjust the metal ion concentration because of the short-time electrolysis.

  As a process of b), the pure water is sufficiently showered and washed, and is kept in a drying furnace with an atmospheric temperature of 150 ° C. for 4 seconds from an electric heater to remove moisture, and a blackening treatment with a very good color tone. A surface-treated copper foil 1 having a surface was obtained. In addition, the scanning electron microscope observation image of the blackening process surface obtained here is the same state as FIG. 7, and there is no change in an external appearance. In addition, in principle, a water washing step with pure water for 15 seconds is provided between the steps described above to prevent the solution from being brought into the pretreatment step.

The cobalt sulfate plating layer of the surface-treated copper foil having the blackened surface obtained as described above has a weight thickness of 338 mg / m ² , a cross-sectional height of 105 nm, and an L value in the Lab color system of 105 The glossiness [Gs (60 °)] was 19, and the black density was 1.30.

  Moreover, the dry film used as an etching resist was bonded together on both surfaces of the said surface treatment copper foil, and the electroconductive mesh pattern was formed by the method similar to Example 1. FIG. As a result, there was no etching residue and very good etching was performed.

  The surface-treated copper foil provided with the blackened surface according to the present invention can be applied to the surface treatment process of the conventional copper foil by adopting the above-described production method, and requires a new production facility. do not do. Accordingly, a high-quality product can be manufactured with a high yield, so that the production cost can be reduced. And, the surface-treated copper foil provided with the blackened surface obtained by the production method according to the present invention has no powder fall off from the blackened surface, and can be etched using a normal copper etching solution. Therefore, a high-quality black mask can be formed by using the electromagnetic wave shielding conductive mesh of the front panel of the plasma display panel. Moreover, since supply as a surface-treated copper foil provided with the blackening process surface can be performed, the blackening process process in the manufacturing process of a front panel can be abbreviate | omitted.

The figure which showed typically the cross-sectional layer structure of the surface treatment copper foil provided with a blackening process surface. The SIM image of the sample which prepared the cross section of the surface treatment copper foil which concerns on this invention with FIB. The SIM image of the sample which prepared the cross section of the conventional surface treatment copper foil with FIB. The SIM image of the sample which adjusted the cross section of the conventional surface treatment copper foil with FIB. The figure which showed typically the cross-sectional layer structure of the surface treatment copper foil provided with a blackening process surface. The figure which showed typically the cross-sectional layer structure of the surface treatment copper foil provided with a blackening process surface. A scanning electron microscope image of the surface of the copper foil on which the cobalt sulfate plating layer is formed without performing the roughening treatment. Scanning electron microscope image of the etching test pattern.

Explanation of symbols

1a, 1b, 1c Surface treatment copper foil 2 Copper foil layer 3 Cobalt sulfate plating layer 4 Rust prevention treatment layer (zinc-nickel alloy layer or zinc-cobalt alloy layer)
5 Chromate treatment layer

Claims (9)

A copper foil having a blackened surface formed by a pulse electrolytic plating method using a cobalt sulfate bath,
The cobalt sulfate plating layer of blackening treatment surface is the weight thickness ^{200mg / m 2 ~400mg / m 2} , and a black surface treated copper foil section height is 200nm or less. The blackened surface-treated copper foil according to claim 1, wherein the blackened surface has an L value in a Lab color system of 27 or more. The blackened surface-treated copper foil according to claim 1, wherein the blackened surface has a gloss [Gs (60 °)] of 30 or less. The blackened surface-treated copper foil according to any one of claims 1 to 3, wherein the blackened surface is provided with a rust-proofing layer. The surface-treated copper foil according to any one of claims 1 to 4, wherein the blackened surface has a black density of 1.0 or more. It is a manufacturing method of the surface treatment copper foil provided with the blackening surface formed by the cobalt sulfate plating in any one of Claims 1-5,
A method for producing a blackened surface-treated copper foil, characterized by using a pulse electrolysis method for cobalt sulfate plating. It is a manufacturing method of the blackening surface treatment copper foil provided with the blackening treatment surface formed by the cobalt sulfate plating in any one of Claims 1-4,
The manufacturing method of the blackening surface treatment copper foil of Claim 7 provided with the blackening treatment surface characterized by providing the process of the following a) and b).
a) Cobalt sulfate containing 10 g / l to 40 g / l of cobalt sulfate (septahydrate) on the surface of the copper foil not subjected to roughening treatment, having a pH of 4.0 or more and a liquid temperature of 30 ° C. or less. Using the plating solution, the cobalt sulfate plating solution is used as a stirring bath at a current density of 4 A / dm ² or less, and pulse electrolysis is performed to form a black cobalt sulfate plating layer.
b) Thereafter, it is washed with water and dried. It is a manufacturing method of the blackening surface treatment copper foil provided with the blackening treatment surface formed by the cobalt sulfate plating of Claim 5,
The manufacturing method of the surface-treated copper foil of Claim 7 provided with the blackening process surface characterized by providing the process of the following a) -c).
a) Cobalt sulfate containing 10 g / l to 40 g / l of cobalt sulfate (septahydrate) on the surface of the copper foil not subjected to roughening treatment, having a pH of 4.0 or more and a liquid temperature of 30 ° C. or less. Using a plating solution as a stirring bath, pulse electrolysis is performed at a current density of 4 A / dm ² or less to form a black cobalt sulfate plating layer.
b) A rust prevention layer is formed on both sides or one side of a copper foil having a black cobalt sulfate plating layer formed on the surface.
c) Thereafter, it is washed with water and dried. An electromagnetic wave shielding metal mesh for a front panel of a plasma display obtained by using the blackened surface-treated copper foil according to any one of claims 1 to 5.