WO2005064044A1

WO2005064044A1 - Bronzing-surface-treated copper foil, process for producing the same, and electromagnetic wave shielding conductive mesh for front panel of plasma display utilizing the bronzing-surface-treated copper foil

Info

Publication number: WO2005064044A1
Application number: PCT/JP2004/019006
Authority: WO
Inventors: Tsutomu Higuchi
Original assignee: Mitsui Mining & Smelting Co.,Ltd.
Priority date: 2003-12-26
Filing date: 2004-12-20
Publication date: 2005-07-14
Also published as: KR20060067921A; TW200526111A; JP4354271B2; JP2005187913A; CN1777705A; CN100567584C; KR100738164B1; TWI301049B

Abstract

A surface-treated copper foil that is free from powder fall, having a bronzing-treated layer of uniform color tone and that does not contain foreign metals becoming an etching inhibiting factor so as to attain further facilitation of etching operation. Thus, there is provided a bronzing-surface-treated copper foil being a copper foil having a bronzing-treated surface formed by copper plating performed in multiple stages, wherein the cross-sectional height of the bronzing-treated surface is 150 nm or less. This bronzing-treated surface is characterized by, for example, exhibiting an a-value in Lab color system of 4.0 or less. This surface-treated copper foil is produced fundamentally through a process comprising the steps of (a) fundamental plating operation, (b) additional plating operation, (c) coating plating operation, (d) finishing plating operation and (e) washing/drying operation.

Description

Specification

TECHNICAL FIELD The present invention relates to a browned surface-treated copper foil, a method for producing the same, and an electromagnetic wave shielding conductive mesh for a front panel of a plasma display using the browned surface-treated copper foil.

The present invention relates to a surface-treated copper foil having a browned surface, a method for producing the surface-treated copper foil, and an electromagnetic shielding conductive mesh for a front panel of a plasma display using the surface-treated copper foil.

Background art

[0002] The conductive mesh for shielding of a plasma display panel has changed from a metallized fiber fabric to a conductive mesh. Several methods have been established for the production of this conductive mesh. One method is to laminate the surface-treated copper foil on a PET film and attach them together, and then to manufacture them using photolithographic etching. The other is a conductive mesh of the surface-treated copper foil alone, in which the surface-treated copper foil is etched together with the supporting substrate by photolithographic etching, and then the supporting substrate is peeled off.

[0003] Further, in response to recent demands for power saving, development has been carried out with a target of a plasma generation signal voltage of 200 V to 50 V, and in order to compensate for a decrease in luminance due to the decrease in the voltage, a conductive property is required. Attempts have been made to reduce the circuit width of the mesh to reduce the coverage of the front glass panel with the conductive mesh. Therefore, the thickness of the conductive mesh has been reduced to facilitate the etching. One of them is to form a seed layer as a seed for electric plating on a PET film by sputtering vapor deposition, and then to form a thin copper layer with electrolytic copper plating, etc., and to reduce the mesh line width by photolithographic etching. The production of conductive mesh has been carried out.

[0004] Although the conductive mesh is manufactured by the method of V, the conductive mesh itself is incorporated in the front panel and the surface force can be visually recognized through the front glass. One side of the surface-treated copper foil is processed from dark brown to black to enhance the brightness of transmitted light. Conventionally, this processing is a technique of a multilayer printed wiring board, and is a technique for improving adhesion between an inner layer circuit and a resin layer. It has been diverted to surface treatment using different metals such as nickel or cobalt.

[0005] Non-Patent Document 1: Technical Trends of PDP Materials Hitachi Chemical Technical Report No. 33 (1999

7)

Patent Document 1: JP-A-11-186785

Patent Document 2: JP-A-2000-31588

Disclosure of the invention

Problems to be solved by the invention

[0006] However, there is a serious problem with the above-mentioned black-and-white processing. That is, when a large amount of black oxide of copper is applied to the surface of the copper foil, a good blackened surface is certainly obtained. However, as the amount of copper black oxide formed on the surface of the copper foil increases, it tends to fall off from the blackened surface, causing a so-called powder dropping phenomenon, which damages the blackened surface. Soon handling becomes difficult.

[0007] When the powder dropping phenomenon occurs, the dropped black oxide is mixed into an unnecessary portion, or is dispersed in the transparent adhesive layer during the transparency treatment for integrating with the glass of the front panel, and the transparency is reduced. Can also be a factor of deteriorating.

[0008] On the other hand, as a blackening treatment capable of forming a good blackened surface, general black nickel plating, sulfur plating nickel plating, cobalt plating, and the like have been studied. The problem has arisen that the etching process cannot be performed from the blackened surface side in the process. In particular, surface-treated copper foil, which has a blackened surface on which cobalt and nickel are deposited in a rich manner, cannot solve the problem of powder dropping and is an expensive product because it uses a large amount of expensive nickel and the like. Was.

[0009] On the other hand, the technology for manufacturing plasma display panels has matured, and conventionally, a surface-treated copper foil having only a good blackened surface has been demanded. A high level of blackness is not necessary, but rather a low price, but an electromagnetic wave shielding mesh having a mesh pattern with a high aperture ratio that is easy to etch and has a stable light transmittance has been desired. Was.

[0010] Therefore, there is a problem in that the copper foil having a black-colored black coating film currently distributed on the market has difficulty in etching the cobalt layer using a copper etchant. Attempts have been made to reduce the amount of dissimilar metals to brownish tones.

[0011] Certainly, considering that the condition of low cost is satisfied and that etching is easy, do not blacken the surface of the surface-treated copper foil! / It is expected that the market will be supplied in this state. However, the use of dissimilar metals such as cobalt and nickel also makes no difference in the load of etching waste liquid treatment, and completely eliminates the difference in etching performance with copper foil that does not contain dissimilar metals, which is a factor inhibiting etching. It is impossible to eliminate it.

The drawback of the conventional surface-treated copper foil having a brownish surface is that the brownish surface is not uniform in color but has unevenness on the entire surface. In other words, it is not possible to uniformize the brown treatment in the same plane. Strictly speaking, when trying to etch from the brown surface, the cross-sectional shape of the mesh obtained by etching may vary. It had become. Moreover, the brown surface is in a matte state, and is easily damaged by rubbing the surface lightly! Was the thing.

[0013] Therefore, in the field, the electromagnetic wave of the plasma display panel is provided with a browning treatment layer having a uniform brownish color, and not containing a dissimilar metal which becomes an etching hindrance so that etching can be performed more easily. Surface-treated copper foil for shielding mesh has been desired.

Means for solving the problem

[0014] The inventors of the present invention have conducted intensive studies and found that when a surface-treated copper foil is manufactured by the following manufacturing method, a surface treatment that does not include a dissimilar metal, which is a conventional etching inhibiting factor, does not exist. I came up with the idea that copper foil could be obtained.

[0015] <Brown surface-treated copper foil>

The browned surface-treated copper foil described below is a copper foil provided with a browned surface formed by copper plating performed in multiple stages, as in a manufacturing method described later. In the present invention, the “multi-stage copper plating” refers to a copper plating process that employs two or more plating processes instead of being formed by a single plating process. Here, as the base copper foil, either an electrolytic copper foil or a rolled copper foil can be used. When using electrolytic copper foil, either its glossy surface or rough surface is selectively used. It becomes possible.

[0016] The first characteristic of the surface-treated copper foil according to the present invention is that the browned surface has a cross-sectional height of 150 nm or less, which is not extremely rough. Is the first feature. That is, it can be said that the surface is extremely smooth and has a glossy browning. However, to avoid misunderstanding, it should be specified, but it is natural that there is variation within the normal manufacturing process, and it is not necessary that the cross-sectional height at all positions be 150 nm or less. It is natural that there may be cross-sectional heights exceeding 150 nm that reflect variations in the manufacturing process. FIG. 1 shows a FIB observation image obtained by observing a cross section using a FIB analyzer in order to measure the cross-sectional height of the browned surface 2 of the surface-treated copper foil 1 according to the present invention. FIG. 1 shows an electro-deposited copper foil formed with a browned surface on a glossy surface. This FIB observation image was observed from a direction having an angle of 60 ° with respect to the surface to be observed.

As can be seen from FIG. 1, it is clear that the cross section of the browned surface has certain irregularities. When such irregularities are monitored, a stylus-type surface roughness is used. It is common to use a meter. However, as shown in Fig. 1, it is considered that the surface roughness is at a level that makes it impossible to accurately measure the roughness. Therefore, in the present invention, the maximum difference between the peak and the valley in the field of view of the FIB observation image is defined as the “cross-sectional height” as a value corresponding to Rmax measured by a surface roughness meter. The local force indicated by "d" in Fig. 1 is the cross-sectional height of Fig. 1, which can be determined to be about 80nm. In Fig. 1, the browning surface 2 in Fig. 1 is formed with an extremely uniform thickness along the shape of the copper foil surface, and maintains a state of perfect adhesion to the underlying copper foil surface. No trouble spots such as the raised browning surface 2 were found, and no spots that would give a sense of powder falling were found.

On the other hand, when the cross-sectional force FIB analysis is performed on the browned surface of the conventional copper foil having the browned surface in the same manner as described above, the result shown in FIG. 2 is obtained. In other words, it is a force that the shape constituting the browned surface grows like a dendrite and is considerably protruded from the underlying copper foil. Therefore, when the cross-section height (d) at this time is measured, it is about 180 nm, and it can be understood that the surface is considerably rough. Also, such a browned surface having a branch shape is a surface whose dendrites are easily broken and easily damaged. Of course, if the broken pieces fall off, it is natural that powder will fall off, which is considered to be the cause of color unevenness when visually observed from the browned surface.

It can be understood that the surface-treated copper foil according to the present invention described above has an extremely smooth surface even from the FIB cross-sectional observation image in FIG. However, although it is a glossy browning treatment, it does not have a gloss enough to diffusely reflect the light received by the browning treated surface, and the browning treatment was applied to the glossy surface of the electrolytic copper foil and the surface of the rolled copper foil. Even in this case, the a value in the Lab color system is less than 4.0. Here, as described as 4.0 or less, it includes a matte state showing a negative value as gloss. Such a browned surface in the matte state is easily formed when the roughened surface of the electrolytic copper foil is subjected to the browning process.

[0020] Whether or not the surface of the browned surface is in a matte state is more preferably expressed using glossiness than in the Lab color system. However, the glossiness of the browned surface according to the present invention should be classified according to the type of the substrate forming the browned surface. One is that when the browned surface is a glossy surface of an electrolytic copper foil or a surface of a rolled copper foil with the browned surface, the glossiness [Gs (60 °;)] is obtained. It is preferable that it is 10 or less. When the degree of gloss is 10 or more, a so-called black glow is created, and the metallic luster becomes conspicuous.

[0021] Then, in the case where an uneven base such as a rough surface of an electrolytic copper foil is selected, it is desirable that the browning-treated surface has a gloss [Gs (60 °)] of 3 or less. is there. When the glossiness is 3 or more, it is more likely that the surface has a surface that is easy to fall off due to the relationship between the browning surface and the shrinkage.

[0022] It is also preferable that the browning surface is provided with a water-proof treatment layer. This is a glass that can ensure long-term storage properties of the surface-treated copper foil according to the present invention. The protective layer does not cause discoloration of the browning layer, and if it can be easily dissolved by a copper etchant, it can be an inorganic protective layer such as zinc or brass, benzotriazole, imidazole, or the like. It is also possible to use deviations such as organic protection.

<Method for Producing Surface-treated Copper Foil with Browning Surface> (Production method 1 of surface-treated copper foil with browning treated surface)

The basic method for producing a surface-treated copper foil having a blackened surface according to the present invention includes the following steps a to e. The feature is that the copper plating that forms the browned surface is divided into multiple plating processes instead of being formed by a single plating operation, and copper plating is performed in multiple stages. Hereinafter, each step will be described.

Step a: This is the first plating treatment for browning the surface of the copper foil using the copper sulfate plating solution under the plating condition (hereinafter referred to as “basic plating treatment”). This is called the basic plating process.

[0025] Here, the copper foil to be plated in the basic plating step may be subjected to a roughening treatment or a roughening treatment, or may be roughened. This roughening treatment is performed in order to obtain good adhesion to a base material to be laminated, for example, by attaching fine copper particles or by attaching a copper-colored oxidized product that looks black. It was intentionally roughened by the method described above.

In this basic plating step, plating processing is performed under so-called copper plating conditions.

However, the plating performed in the basic plating process is for forming a nucleus for forming a certain degree of unevenness on the copper foil surface, and the surface of the copper foil after the basic plating process is observed with a scanning electron microscope. Does not appear to be clearly roughened.

[0027] Accordingly, the amount of plating to be electrodeposited in the basic plating step is a converted thickness (hereinafter simply referred to as a "converted thickness") assuming that a completely smooth and flat flat surface is plated. 3 OOmgZm ² - should be 600MgZm ² about electrodeposition amount. If it is less than 300 mgZm ² , it cannot be said that nuclei for sufficient roughening have been formed, and even if the additional plating treatment described later is performed, a good browned surface cannot be formed. On the other hand, when it exceeds 600 mgZm ² , if an additional plating treatment described later is performed, the roughening treatment proceeds excessively, so that the powder easily falls off and a browned surface is formed.

[0028] The conditions of the damage here are not particularly limited, but are determined in consideration of the characteristics of the production line. For example, if a copper sulfate solution is used, the concentration of copper is 5-20 gZl, sulfuric acid is 50-200 gZl, other additives (α-naphthoquinoline, dextrin, dika, thiourea, etc.), and the liquid temperature 15- 40 ° C, and the like to a current density of 10- 50AZdm ^2. Step b _: This step is an additional plating treatment step of subjecting the surface of the copper foil that has been subjected to the basic plating treatment to one or more additional plating treatments using a copper sulfate plating solution under a plating condition. The same conditions as in step a. Can be used for the scoring conditions in this additional plating treatment step, but since there are nuclei that will form irregularities on the copper foil surface in step a. It is preferable that the current density be less than half of that in step a. To prevent the current from concentrating on the underlying nucleus and prevent unnecessary abnormal deposition. That is, the current density (la) used when performing the scuffing in the step b is set to be 50% or less of the la, while the current density (la) used when performing the scuffing in the step a.

Here, it is also possible to perform two or more times of plating processes, as described as “one or more additional plating processes”. However, the plating surface formed by the basic plating process and the additional plating process at this time uniformly coats the plating surface to be treated, which does not form a visually roughened unevenness, and is somewhat mild. It is only necessary to be able to create a roughened state. Therefore, it should be noted that it is necessary to control the total current and the total electrolysis time between the basic plating process and the additional plating process in order to create a mild rough state.

Based on the plating amount in the basic plating step described above, the appropriate electrodeposition amount in the additional plating step should be about 50 mgZm ² to 300 mgZm ² in terms of reduced thickness. If it is less than 50 mg / m ² , it is not possible to impart an appropriate uneven shape to the surface formed with nuclei in step a, and a favorable browned surface cannot be obtained. On the other hand, if it exceeds 300 mgZm ² , the nucleus formed in step a becomes excessive, and a browned surface that is easy to fall off is formed.

Step c: This step is a coating plating treatment step of performing plating treatment on the copper foil surface subjected to plating in Steps a and b under a smooth plating condition using a copper plating solution. The coating process is a plating process for smoothing the surface roughened in the steps a and b, and is a process for uniformly depositing copper so as to cover the roughened surface. Therefore, here, it is possible to use all of the copper electrolytes that can smooth copper. The conditions of the smooth plating are determined in consideration of the characteristics of the production line, which is not particularly limited. For example, if a copper sulfate solution is used, the concentration of copper should be 50-80. GZL, and the like to sulfuric 50- 150gZl, liquid temperature 40- 50 ° C, a current density of 10- 50AZdm ^2.

[0033] However, electrolysis time, so that is not too smooth Soi匕shape by Yakemetsuki, as the conversion thickness when formed into a complete and smooth and flat surface Hemetsuki process, 5g / m ² - 10g Zm The electrodeposition should be about ² . If it is less than 5 g / m ² , the effect of smoothing the surface roughened in the steps a and b cannot be obtained. On the other hand, when lOgZm ² is exceeded, the surface roughened in steps a and b becomes too smooth, and the color of the browned surface increases the metallic luster.

Step d: This step is a plating treatment for finishing the copper foil surface to a brown color by using a copper plating solution under the plating condition on the surface subjected to the smooth plating treatment after the completion of the step c (hereinafter referred to as “the plating treatment”). This is referred to as “finish plating processing”). In this step, the difference between the plating process and the above-mentioned basic plating process and additional plating process is that in this process, the roughening treatment is performed using extremely fine copper particles (hereinafter, referred to as “ultra-fine copper particles”). It is done using it.

[0035] In forming the ultrafine copper particles, a copper electrolyte containing arsenic is generally used. One example of electrolysis conditions cases according, a a copper sulfate solution, the concentration of copper 10gZl, 1 OOg / U arsenic 1. 5GZl sulfate, liquid temperature 38 ° C, equal to the current density 30AZdm ² Was. However, according to the present invention, a copper electrolyte to which 9-phenylacrylidine is added instead of arsenic is used as an additive having a lower possibility of affecting the human body due to the rise of environmental problems in recent years. 9 Ferracridine plays a role similar to that of arsenic in the field of copper electrolysis, enabling the sizing effect of fine copper particles deposited and uniform electrodeposition. That is, as a copper electrolyte for forming ultra-fine copper particles added with 9-phenylacridine, the concentration of copper is 5 to 15 gZl, free sulfuric acid is 40 to 100 gZl, 9-phenylatalidine is 50 to 300 mg / l, A chlorine concentration of 20 ppm to 32 ppm, a liquid temperature of 30 to 40 ° C, and a current density of 20 to 40 A / dm ² are within the range where extremely stable electrolytic operation can be performed. More preferably, copper is 10 to 15 gZl, free sulfuric acid is 40 to 70 gZl, 9 phenylacridine is 100 to 200 mg / U, chlorine concentration is 25 ppm to 30 ppm, and liquid temperature is 30 to 40. C, current density is in the range of 20-40 AZdm2. This range is most excellent in operation stability and solution stability as a plating solution, The production yield of the surface-treated copper foil according to the present invention is increased.

Step e: This step is a washing and drying step after completion of each of the above steps, washing with water and drying to obtain a browned surface-treated copper foil. There are no special conditions for washing and drying that can be performed in accordance with the usual methods. However, the rinsing referred to here simply means the final rinsing, and rinsing that can be considered within a common sense is appropriately provided between each process so as not to bring the solution of the previous process into the subsequent process. Please note that.

(Method 2 for producing surface-treated copper foil having browning-treated surface)

This production method is a method for producing a browned surface-treated copper foil including the following steps a to f.

[0038] Step a: Basic plating treatment in which the first plating treatment for browning the surface of the copper foil (hereinafter referred to as "basic plating treatment") is performed using a copper sulfate plating solution under the covering condition. Process.

Process b: An additional plating process in which a copper sulfate-based plating solution is subjected to one or more additional plating processes on the surface of the copper foil that has been subjected to the basic plating process, under a plating condition.

Step c: A coating plating treatment step in which the copper foil surface subjected to plating in Steps a and b is plated with a copper sulfate plating solution under smooth plating conditions.

Step d: On the surface that has been subjected to the step c and has been subjected to the smooth plating treatment, a plating treatment for finishing the copper foil surface to brown using a copper sulfate plating solution under the plating condition (hereinafter referred to as `` finish plating treatment ''). Finishing process for applying a finish.

Step e: a water-proofing treatment step of performing a water-proofing treatment on the surface of the copper foil which has been subjected to the browning treatment by the above steps.

Step f: After each of the above steps, a washing and drying step of washing and drying to obtain a browned surface-treated copper foil.

As is apparent from the above steps, this is a step in which a protection process is added to the manufacturing method 1. Therefore, in order to avoid redundant description, only the protection process will be described.

[0040] In the anti-shearing treatment step, the surface of the surface-treated copper foil is prevented from being oxidized and corroded without causing discoloration of the browned surface and being easily removed by etching with a copper etching solution. Benzotriazole, imidazole, etc. are used for this protection treatment. It does not matter whether the organic barrier used or the inorganic barrier using zinc, chromate, zinc alloy or the like is adopted. What is necessary is just to select the protection in accordance with the intended use of the surface-treated copper foil. In the case of organic protection, it is possible to adopt a method such as dip coating, showering coating, and electrodeposition of an organic protection agent. In the case of inorganic protection, it is possible to use a method in which a protection element is deposited on the surface of the surface-treated copper foil by electrolysis, or a so-called displacement deposition method. For example, a zinc pyrophosphate plating bath, a cyanide zinc plating bath, a zinc sulfate plating bath, or the like can be used as the zinc prevention treatment. For example, if the pyrophosphate galvanizing bath, concentration of zinc 5-30GZl, potassium pyrophosphate 50- 500GZl, liquid temperature 20- 5 0 ° C, pH9- 12 , and a current density of 0. 3- lOAZdm ² And so on.

[0041] Further, it does not affect the color tone of the browned surface of the surface-treated copper foil according to the present invention! / The plating treatment is performed using a zinc-nickel alloy plating solution or a zinc-cobalt alloy plating solution as an inorganic protection. Are preferred. First, zinc-nickel alloy plating will be described. The zinc-nickel alloy plating solution used here is not particularly limited.Examples include, for example, nickel sulfate having a nickel concentration of 12.5 gZl, zinc pyrophosphate having a zinc concentration of 0.1 lgZl, and pyrophosphoric acid. Potassium acid salt 50-500gZl, liquid temperature 20-50. C, pH 8-11, current density 0.3-IOAZdm ² etc. are adopted.

Next, zinc-cobalt alloy plating will be described. The zinc-conoleto alloy plating solution used here is not particularly limited, but, for example, for example, the cobalt concentration is 1-2.5 g / l using cobalt sulfate, and the zinc concentration is 0.1-2.5 g using zinc pyrophosphate. lg / l, potassium pyrophosphate 50-500 gZl, liquid temperature 20-50. C, pH8-11, current density. 3—Use the conditions of lOAZdm ² . The anti-corrosion treatment layer obtained by combining this zinc-cobalt alloy plating with the chromate treatment described later exhibits particularly excellent corrosion resistance.

Further, in order to enhance the anti-corrosion effect, if a chromate layer is formed after forming a zinc-nickel alloy layer or a zinc-cobalt alloy layer on the surface of the surface-treated copper foil, more excellent corrosion resistance can be obtained. You can get it. That is, the chromate treatment may be performed after the formation of the above-described heat-resistant treatment layer. In the chromate treatment step, any of a substitution treatment in which a chromate solution is brought into contact and an electrolytic chromate treatment in which a chromate film is formed by electrolysis in a chromate solution may be employed. Also, the chrome used here Regarding the salt solution, it is possible to use those in the range used in a usual manner. After that, it is washed with water and dried to obtain a surface-treated copper foil having a browned surface.

The invention's effect

[0044] The surface-treated copper foil provided with the browned surface according to the present invention described above does not fall off from the browned surface, and has a very uniform brown color without unevenness. The browning layer can be removed by etching using a normal copper etching process. Therefore, it is possible to easily process the printed wiring board into an arbitrary shape by using a process for manufacturing the printed wiring board. Considering these facts, it can be said that it is the most suitable for the application of the electromagnetic wave shielding conductive mesh incorporated in the front panel of the plasma display panel.

[0045] Further, the method for producing a surface-treated copper foil according to the present invention is a conventional method in which a browned surface is efficiently formed on the surface of a copper foil by employing a multi-stage copper plating method. This made it possible to minimize the variation in the color tone of the surface-treated copper foil having the browned surface.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, results of producing the above-described surface-treated copper foil having the browned surface and producing an electromagnetic wave shielding conductive mesh using a copper etching solution will be shown.

Example 1

[0047] In the present embodiment, the surface is subjected to a roughening treatment! / ヽ A browning treatment is performed on the glossy surface using an electrolytic copper foil! Was experimentally manufactured by the etching method, and the etching performance was confirmed.

[0048] In the present embodiment, a copper foil with a nominal thickness of 10 Pm obtained by electrolyzing a copper sulfate solution was used. Then, the electrolytic copper foil was immersed in a dilute sulfuric acid solution having a sulfuric acid concentration of 150 gZl and a liquid temperature of 30 ° C. for 30 seconds to clean the surface. Hereinafter, each process will be described.

Step a: Here, the roughing treatment is performed, and the light of the copper foil of the belly rope mouth file is used. Sawamen (Ra = 0.m, Rz = l.54 ^ m) was subjected to basic plating treatment to make the surface of the copper foil brown using a copper sulfate plating solution under the condition of undercoating.

[0050] The basic plating treatment condition used at this time was a copper sulfate solution, which was electrolyzed under the following conditions: copper concentration 18gZl, free sulfuric acid concentration 100gZl, solution temperature 25 ° C, current density (la) lOAZdm ^2. It was done by doing. As a result, in the plating performed in the basic plating process, only a nucleus for forming a certain degree of unevenness on the copper foil surface was formed, and the electrodeposition amount was 300 mg Zm ^{2 in} terms of reduced thickness.

Step b _{: In} this additional plating treatment step, one plating treatment was performed on the surface of the copper foil that had been subjected to the basic plating treatment, using a copper sulfate-based plating solution under scorching conditions. The additional plating treatment conditions at this time were the same concentration and liquid temperature of copper sulfate solution as in step a., But the current density (lb) used when performing plating was changed to 15% of la As 1.5AZdm ² , current concentration on the nuclei formed on the surface of the copper foil in step a. Was prevented to prevent unnecessary abnormal precipitation. The electrodeposition amount during this additional plating step was an electrodeposition amount of 50 mgZm ² as a converted thickness.

Step c: In this coating plating treatment step, the copper foil surface subjected to plating in steps a and b was subjected to plating treatment under a smooth plating condition using a copper plating solution. As in this coating message Kie, a copper sulfate solution, the copper concentration 65GZl, free sulfuric acid concentration 150GZl, liquid temperature 4 5 ° C, and electrolysis was performed with smooth plated a current density 15AZdm ^2. Thus, the surface subjected to the roughening treatment in the steps a and b was smoothed. At this time, the converted thickness of the smooth plating was 4 gZ m (?

Step d: In this finish plating treatment step, the surface subjected to the step c and subjected to the smooth plating treatment is subjected to a plating treatment for finishing the surface of the copper foil to brown using a copper plating solution under the plating condition. Thus, extremely fine copper particles were adhered and formed.

For the formation of the ultrafine copper particles, the following copper sulfate solution prepared by adding 9-phenylacrylidine was used. As the copper electrolyte and the electrolysis conditions, a copper concentration of 13 gZl, free sulfuric acid of 50 gZl, 9-phenylacridine of 150 mgZl, a chlorine concentration of 28 ppm, a liquid temperature of 35 ° C., and a current density of 24 AZdm ² were used. The electrodeposition amount in the finish plating process was an electrodeposition amount of 300 mgZm ² as a converted thickness. Step e: In this washing / drying step, after the above-mentioned step d. Is completed, the deionized water is sufficiently washed by washing, and placed in a drying furnace with an atmosphere temperature of 150 ° C. from an electric heater. The sample was allowed to stay for 4 seconds to remove moisture, and a surface-treated copper foil having a browned surface with a very good color tone was obtained. In addition, not only the water washing here, but also water washing between the steps was appropriately provided between the steps so that the solution of the previous step was not carried into the subsequent step.

As a result of observing the cross section of the surface-treated copper foil having the browned surface obtained through the above steps with a FIB apparatus, the cross section shown in FIG. 1 was obtained, and the cross-sectional height of the browned surface ( d) was 80 nm, the a value of the browned surface in the Lab color system was 3.5, and the gloss [Gs (60 °;)] was 2.8. In addition, a sticky tape was applied to the browned surface, and a powder test in peeling off the adhesive tape was confirmed.

A dry film serving as an etching resist was bonded to both surfaces of the surface-treated copper foil obtained as described above. Then, only the dry film on the browned surface side is overlaid with a mask film for testing to produce an electromagnetic shielding conductive mesh, and the mesh pitch is 200 m, the mesh line width is 10 μm, and the mesh bias angle is 45 °. Then, a conductive mesh pattern having a mesh electrode portion on the periphery was exposed to ultraviolet light. At this time, the entire surface of the etching resist layer on the opposite side was also exposed to ultraviolet light so that it could not be removed by subsequent development. Thereafter, development was performed using an alkaline solution to form an etching pattern.

[0058] Then, copper etching is performed from the browning-treated surface side using a copper salt etching solution, which is a salt etching solution, and then the etching resist layer is peeled off to produce an electromagnetic wave shielding conductive mesh. did. As a result, very good etching was performed with no etching residue.

Example 2

[0059] This embodiment is different from the first embodiment only in that a protection process is provided between step d and step e of the first embodiment. Therefore, the steps a, b, and d are the same as those in the first embodiment, and a duplicate description is avoided, and only the step e. I will explain it.

Step e .: In this protection treatment step, a plating treatment was performed using a zinc-nickel alloy plating solution to form a zinc-nickel alloy layer on both surfaces. Zinc-nickel alloy layer, the nickel concentration with sulfate nickel 2. OgZl, zinc concentration using pyrophosphate zinc 0. 5 GZL, potassium pyrophosphate 250GZl, liquid temperature 35 ° C, pH 10, the current density 5AZdm ² Electrolysis was performed for 5 seconds under the same conditions to uniformly and uniformly deposit on both surfaces.

Step f: This washing / drying step corresponds to step e. Of Example 1. After the above-mentioned step e. Is completed, it is sufficiently washed with water, dried by heating, and provided with a browned surface. The surface-treated copper foil was used, and the details are the same as in Example 1.

[0062] <Physical properties of surface-treated copper foil>

As a result of observing the cross section of the surface-treated copper foil provided with the browned surface obtained through the above steps with a FIB device, a cross section similar to that shown in Fig. 1 was obtained. Was 85 nm, the a value of the browned surface in the Lab color system was 3.6, and the gloss [Gs (60 °;)] was 2.6. In addition, a sticky tape was applied to the browned surface, and a powder test in peeling off the adhesive tape was confirmed.

In the same manner as in Example 1, an electromagnetic wave shielding conductive mesh was prototyped using the obtained surface-treated copper foil. As a result, very good etching was performed with no residual etching that hindered the etching operation even when the anti-reflection treatment layer was present.

Example 3

[0064] In Example 1, a blackened surface was formed on the glossy surface of the copper foil with a nominal thickness of 10 µm, which is an electrolytic copper foil. They produced surface-treated copper foil with a treated surface. First, in the same manner as in Example 1, the electrolytic copper foil was immersed in a dilute sulfuric acid solution having a sulfuric acid concentration of 150 gZl and a liquid temperature of 30 ° C. for 30 seconds to clean the surface. Hereinafter, each process will be described.

Step a: Here, roughing treatment is performed, and a copper sulfate-based plating solution is applied to the rough surface (Ra = 0.m, Rz = 2.m) of the copper foil of the belly rope opening file. Article In this case, a basic plating treatment for browning the surface of the copper foil was performed. The surface roughness of the rough surface of the single-profile copper foil with a belly opening was such a low profile that it did not hinder the glossy surface. Hereinafter, steps a (basic plating processing step), step b (additional plating processing step), step c. (Coating plating processing step), step d (finishing plating processing step), and step e (same as in Example 1) After washing and drying steps), a surface-treated copper foil having a browned surface was obtained.

[0066] <Physical properties of surface-treated copper foil>

As a result of observing the cross section of the surface-treated copper foil provided with the browned surface obtained through the above steps with a FIB device, a cross section similar to that shown in Fig. 1 was obtained. Was 75 nm, the a-value of the browned surface in the Lab color system was 3.6, and the gloss [Gs (60 °;)] was 1.2. In addition, a sticky tape was applied to the browned surface, and a powder test in peeling off the adhesive tape was confirmed.

Example 4

[0068] In Example 2, a blackened surface was formed on the glossy surface of a copper foil with a nominal thickness of 10 µm, which is an electrolytic copper foil, and the blackened surface was formed on the rough side in the present embodiment. They produced surface-treated copper foil with a treated surface. First, the surface of the electrolytic copper foil was cleaned using the procedure of Example 1 as in Example 2. Hereinafter, each step will be described.

Here, the same procedure as in Example 3 was performed on the rough surface (Ra = 0.35 ^ ππ, Rz = 2.32 / zm) of the copper box with the above-mentioned belly rope mouth file, which was not subjected to the roughing treatment. Steps a (basic plating processing step), step b (additional plating processing step), step c. (Coating plating processing step), and step d (finish plating processing step) were performed in the same manner as in row 1. Then, unlike in Example 3, step e. (A protection step) is added, and after step f. Thus, a surface-treated copper foil provided with was obtained. In the process e. (The heat-proofing process) at this time, the zinc-nickel alloy layer was formed in the same procedure as in the second embodiment. Therefore, the above steps have been described in the above embodiment, and the duplicate description will be omitted.

[0070] <Physical properties of surface-treated copper foil>

As a result of observing the cross section of the surface-treated copper foil provided with the browned surface obtained through the above steps with a FIB device, a cross section similar to that shown in Fig. 1 was obtained. Is 74 nm, the a value of the browned surface in the Lab color system is 3.8, and the gloss [

Gs (60 °;)] was 1.5. In addition, a sticky tape was applied to the browned surface, and a powder test in peeling off the adhesive tape was confirmed.

Comparative Example 1

[0072] In this comparative example, the copper concentration of the copper sulfate solution used in step d. Of Example 1 was lowered, and the copper concentration was removed under the optimum conditions to form the adhesion of ultrafine copper particles. Therefore, only step d. Will be explained.

Step d: In this finishing step, the copper concentration of the following copper sulfate solution to which 9-fluoroacrylidine used in Example 1 was added was set to 8 gZl. Then, the electrodeposition amount in the finish plating process was 300 mgZm ² as the converted thickness in the same manner as in Example 1.

As a result of observing the cross-section of the surface-treated copper foil provided with the browned surface obtained through the above steps with a FIB apparatus, the cross-section shown in FIG. 2 was obtained, and the cross-sectional height (d ) Force Sl80 nm, a value in the Lab color system of the browned surface was 3.6, and gloss [Gs (60 °;)] was 2.6. When compared with the above example, the surface roughness that caused abnormal growth of the bumps due to the finish plating process and that caused powder drop-off showed that the comparative power of FIGS. 1 and 2 was also evident. It turns out that it is. As for the pressing force, color unevenness was observed in the same surface of the browned surface. In addition, a powder test was carried out by applying an adhesive tape to the browned surface and peeling it off.

In the same manner as in Example 1, an electromagnetic wave shielding conductive mesh was prototyped using the obtained surface-treated copper foil. As a result, the browning-treated surface of the surface-treated copper foil obtained in this comparative example was rubbed at the time of handling, although the etching operation was not hindered even when the heat-resistant treatment layer was present. It was difficult to maintain the browned surface of the area immediately after the completion of the etching process.

Industrial applicability

[0076] The surface-treated copper foil provided with the browned surface according to the present invention has no unevenness in color. The browned surface having excellent scratch resistance is provided, and the power to remove powder from the blackened surface is also high. In addition, the etching force can be reduced using a normal copper etching solution, and a high-quality black mask can be formed by using a conductive mesh for shielding electromagnetic waves on a front panel of a plasma display panel. Further, by supplying as a surface-treated copper foil having a browning-treated surface, it is possible to omit the blackening process in the front panel manufacturing process.

[0077] In addition, in forming the browned surface, a multi-step copper plating method is employed, and a production method of performing smooth plating and finishing plating is employed, whereby the surface-treated copper foil according to the present invention is obtained. Since production can be performed with a high yield, production costs can be reduced.

Brief Description of Drawings

FIG. 1 is a diagram schematically showing a cross-sectional layer configuration of a surface-treated copper foil having a browned surface.

FIG. 2 is a diagram schematically showing a cross-sectional layer configuration of a surface-treated copper foil having a browned surface. Explanation of symbols

[0079] 1 Surface-treated copper foil

2 Browned surface

Claims

The scope of the claims

[1] A copper foil having a browned surface formed by multi-stage copper plating, wherein the cross-sectional height of the browned surface is 150 nm or less. Foil

2. The browned surface-treated copper foil according to claim 1, wherein the browned surface has an a value of 4.0 or less in a Lab color system.

[3] The browned surface-treated copper foil according to claim 1, wherein the browned surface is provided with a water-proofing treatment layer.

[4] The browning-treated surface is formed by forming the browning-treated surface on the glossy surface of an electrolytic copper foil or the surface of a rolled copper foil, and having a glossiness [Gs (60 °;)] of 10%. The browned surface-treated copper foil according to claim 1, which is as follows.

[5] The method according to claim 1, wherein the browning-treated surface is obtained by forming the browning-treated surface on a rough surface of an electrolytic copper foil, and has a gloss [Gs (60 °;)] of 3 or less. The described browned surface-treated copper foil.

[6] A method for producing a browned surface-treated copper foil according to the present invention, comprising the following steps a to e.

Step a: A basic plating treatment step of applying the first plating treatment to make the surface of the copper foil brown (hereinafter referred to as “basic plating treatment”) by using the copper sulfate plating solution under the covering condition.

Step b: An additional plating treatment step of subjecting the surface of the copper foil subjected to the basic plating treatment to one or more additional plating treatments using a copper sulfate plating solution under the plating conditions.

X @ c: A coating plating treatment step in which a copper sulfate plating solution is applied to the copper foil surface subjected to plating in Steps a and b under plating conditions under smooth plating conditions.

Step d: On the surface that has been subjected to Step c and has been subjected to the smooth plating process, a copper sulfate plating solution is used under the plating conditions to finish the copper foil surface in a brown color (hereinafter referred to as `` finish plating process ''). Finishing process for applying a finish.

Step e: After completion of each of the above-mentioned steps, washing and drying are performed to obtain a browned surface-treated copper foil.

[7] In step b, the current density (la) used when performing 7. The method for producing a browned surface-treated copper foil according to claim 6, wherein the current density (lb) employed when performing the coating is a current density of 50% or less of la.

[8] The copper plating solution used when performing plating in step d has a copper concentration of 5 to 15 g / l, free sulfuric acid of 40 to 100 gZl, 9-phenylacridine of 50 to 300 mgZl, and a chlorine concentration of 20 ppm—

7. The method for producing a browned surface-treated copper foil according to claim 6, wherein the content is 32 ppm.

[9] A method for producing a browned surface-treated copper foil according to the present invention, comprising the following steps a to f.

Step d: On the surface subjected to the smooth plating treatment after the completion of step c, a plating treatment for finishing the copper foil surface to brown by using a copper sulfate plating solution under the plating condition (hereinafter referred to as `` finishing plating treatment ''). Finishing process for applying a finish.

Step e: A water-proof treatment step of performing a water-proof treatment on the surface of the copper foil which has been subjected to the browning treatment by the above steps.

Step f: After completion of each of the above steps, washing and drying are performed to obtain a browned surface-treated copper foil.

[10] In contrast to the current density (la) used when performing the scuffing in step a, the current density (lb) used when performing the scuffing in step b is 50% or less of la. Item 10. The method for producing a browned surface-treated copper foil according to Item 9.

[11] The copper plating solution used for performing plating in step d has a copper concentration of 5 to 15 gZl, 40 to 100 gZl of free sulfuric acid, 50 to 300 mgZl of 9-phenylacridine, and a chlorine concentration of 20 to 32 ppm. 3. The method for producing a browned surface-treated copper foil according to item 1.

[12] A front panel of a plasma display using the browned surface-treated copper foil according to claim 1. Electromagnetic shielding conductive mesh for

[13] An electromagnetic wave shielding conductive mesh for a front panel of a plasma display using the browned surface-treated copper foil according to claim 2.

[14] An electromagnetic wave shielding conductive mesh for a front panel of a plasma display using the browned surface-treated copper foil according to claim 3.

[15] An electromagnetic wave shielding conductive mesh for a front panel of a plasma display using the browned surface-treated copper foil according to claim 4.

[16] An electromagnetic wave shielding conductive mesh for a front panel of a plasma display using the browned surface-treated copper foil according to claim 5.