JP2005187913A - Browning surface-treated copper foil, its production method, and electromagnetic wave shielding conductive mesh for front panel of plasma display obtained by using the browning surface-treated copper foil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide surface-treated copper foil provided with a browning-treated layer free from the falling of powder and having a uniform color tone and comprising no different metals to form into the cause for inhibiting etching so as to further facilitate etching. <P>SOLUTION: The browning surface-treated copper foil is provided with a browning-treated face formed by copper plating performed in a multistage, and the cross-sectional height of the browning-treated face is ≤150 nm. The browning-treated face has the characteristics, e.g., that the a value in an Lab color system is ≤4.0. The surface-treated copper foil is produced fundamentally through a stage a (a fundamental plating treatment stage), a stage b (an additional plating treatment stage), a stage c (a coating plating treatment stage), a stage d (a finish plating treatment stage), and a stage e (a cleaning/drying stage). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  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 wave shielding conductive mesh for a front panel of a plasma display using the surface-treated copper foil.

  The conductive mesh for shielding the plasma display panel has been 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, in order to compensate for the decrease in luminance due to the decrease in the voltage, the circuit width of the conductive mesh has been increased in order to compensate for the decrease in the luminance due to the decrease in the voltage. Attempts have been made to reduce the coverage of the front glass panel by thinning the 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 the method used to produce the conductive mesh, the conductive mesh itself is incorporated into the front panel and is visible from the surface through the front glass, so the surface-treated copper processed into the conductive mesh. One side of the foil is processed from dark brown to black to enhance the brightness of transmitted light. Conventionally, this treatment has been diverted to multilayer printed wiring board technology, blackening treatment to improve the adhesion between the inner circuit and the resin layer, and surface treatment using different metals such as nickel or cobalt. It was.

Technical Trends of PDP Materials Hitachi Chemical Technical Report No. 33 (1999-7) Japanese Patent Laid-Open No. 11-186785 JP 2000-31588 A

  However, the above blackening process has a serious problem. That is, when a large amount of black oxide of copper is applied to the surface of the copper foil, a good blackened surface can be obtained. However, the copper black oxide formed on the surface of the copper foil is more likely to fall off the blackened surface as the amount of adhesion increases, so-called powdering phenomenon occurs, the blackened surface is more likely to be damaged, and handling is easier. It becomes difficult.

  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, general black nickel plating, nickel sulfide plating, cobalt plating, etc. have been studied as blackening treatments that can form a good blackened surface. There has been a problem that etching cannot be performed from the surface side. In particular, the surface-treated copper foil having a blackened surface on which cobalt or nickel is deposited in a rich manner cannot solve the problem of powder falling, and has become an expensive product because it uses a large amount of expensive nickel or the like.

  On the other hand, the manufacturing technology of plasma display panels has matured, and conventionally, a surface-treated copper foil with a simply blackened surface has been required, but with the advancement of manufacturing technology and management, the blackness of the electromagnetic shielding mesh has been increased. However, an electromagnetic wave shielding mesh having a mesh pattern with a high aperture ratio, which is inexpensive, easy to etch, stable in light transmittance, and so on has been desired.

  Therefore, the copper foil provided with a black plating film of cobalt currently on the market has a problem that it is difficult to etch the cobalt layer using a copper etchant, reducing the amount of dissimilar metals. I have tried to make it brownish brown.

  Certainly, considering that the low price is satisfied and that etching is easy, the surface of the surface-treated copper foil should not be blackened, but the amount of deposited cobalt etc. should be reduced and supplied in the brownish state. Will be predicted in the future. However, there is no substitute for using dissimilar metals such as cobalt and nickel, the etching waste liquid treatment is heavy, and the difference in etching performance from copper foils that do not contain dissimilar metals that cause etching inhibition is completely eliminated. Is impossible.

  In addition, the disadvantage of the conventional surface-treated copper foil having a brownish brown surface is that the brownish brown surface is not uniform in color and uneven. That is, the brown color treatment in the same plane has not been made uniform. Strictly speaking, when etching processing is attempted from the brown color surface, it causes the variation in the cross-sectional shape of the mesh obtained by etching. It was. Moreover, the brown surface was in a matte state, and it was easily damaged by merely rubbing the surface.

  Therefore, the surface treatment for the electromagnetic wave shielding mesh of the plasma display panel which is provided with a browning treatment layer having a uniform brown color and does not contain a dissimilar metal which becomes an etching inhibiting factor so that the etching process can be further facilitated. Copper foil has been desired.

  Therefore, as a result of earnest research, the inventors of the present invention, when producing a surface-treated copper foil by the production method as shown below, obtains a surface-treated copper foil that does not contain a dissimilar metal that becomes an etching-inhibiting factor that has not existed conventionally. I realized that I could do it.

<Browned surface treated copper foil>
The browning surface-treated copper foil described below is a copper foil provided with a browning-treated surface formed by copper plating performed in multiple stages as in the manufacturing method described later. In the present invention, “multi-stage copper plating” refers to a copper plating process that employs two or more times of plating processes rather than a single plating process. Here, as the underlying copper foil, either an electrolytic copper foil or a rolled copper foil can be used. And when an electrolytic copper foil is used, it becomes possible to selectively use either the glossy surface or the rough surface.

  The first feature of the surface-treated copper foil according to the present invention is that the surface shape of the browning surface is not very rough, and the cross-sectional height of the browning surface is 150 nm or less. It is the feature. That is, it can be said that it is a browning surface having a very smooth and glossy 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 150 nm or less, Of course, there may be a cross-sectional height of more than 150 nm to reflect the variation in the manufacturing process. In order to measure the cross-sectional height of the browning surface 2 of the surface-treated copper foil 1 according to the present invention, a FIB observation image obtained by cross-sectional observation using a FIB analyzer is shown in FIG. FIG. 1 shows the electrolytic copper foil with a browned surface formed on the glossy surface. The FIB observation image is 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 browning surface has certain irregularities, and in order to monitor such irregularities, a stylus type surface roughness meter is generally used. It is. However, as can be seen from the scale of FIG. 1, 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 FIB observation image is set as the “section height”. The portion indicated by “d” in FIG. 1 is the cross-sectional height of FIG. 1 and can be determined to be about 80 nm. Moreover, in FIG. 1, the browning surface 2 is formed along the shape of the copper foil surface with an extremely uniform thickness, 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 browning treatment surface of the copper foil provided with the conventional browning treatment surface is subjected to FIB analysis from the cross section in the same manner as described above, the result is as shown in FIG. That is, it can be seen that the shape constituting the browning surface has grown 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 is about 180 nm, and it can be understood that the surface is considerably rough. Moreover, it can be said that the browning surface having a dendritic shape is a surface where the dendritic portion is easily broken and easily damaged, and it is natural that if the broken pieces fall off, powdering will occur. This is considered to be a cause of color unevenness when viewed from the browned surface.

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

  Whether the surface of the browning surface is matte or not is preferably expressed using glossiness rather than the Lab color system. However, the glossiness of the browning surface according to the present invention should be classified according to the type of the base on which the browning surface is formed. One is that when the browning surface is a glossy surface of an electrolytic copper foil or a surface of a rolled copper foil and the browning surface is formed, the glossiness [Gs (60 °)] is 10 It is preferable that: When the glossiness is 10 or more, a so-called black shining state occurs and the metallic luster becomes conspicuous.

  And when the foundation | substrate with an unevenness | corrugation like the rough surface of an electrolytic copper foil is selected, it is desirable for the said browning process surface that glossiness [Gs (60 degrees)] is 3 or less. When the glossiness is 3 or more, there is a high possibility that the surface tends to fall off due to the discoloration plating constituting the browning surface.

  Moreover, it is also preferable to provide a rust prevention treatment layer on the browning treatment surface. This is because the long-term storage stability of the surface-treated copper foil according to the present invention can be ensured. If this rust-proofing layer does not cause discoloration of the browning-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.

<Manufacturing method of surface-treated copper foil provided with a browning surface>
(Manufacturing method 1 of surface-treated copper foil provided with a browning surface)
The basic manufacturing method of the surface-treated copper foil provided with the blackening treatment surface in the present invention includes the following steps a to e. Then, the copper plating for forming the browning surface is not formed by a single plating operation, but is divided into a plurality of plating steps, and is characterized in that copper plating is performed in multiple stages. Hereinafter, it demonstrates for every process.

Step a: First plating treatment (hereinafter referred to as “basic plating treatment”) for making the surface of the copper foil brown using a copper sulfate-based plating solution under burn plating conditions. In the present invention, the basic plating treatment is performed. This is called a process.

  Here, the copper foil to be plated in the basic plating step may be subjected to roughening treatment or may be free of roughening treatment. This roughening treatment is applied to obtain good adhesion to the base material to be bonded, and a method of attaching fine copper particles or copper oxide that appears black Is intentionally roughened.

  In this basic plating process, plating is performed under so-called copper burn plating conditions. However, the burn plating performed in this basic plating process is for forming a nucleus for forming a certain degree of irregularities on the copper foil surface, and the surface of the copper foil after the basic plating process is observed with a scanning electron microscope. However, it does not appear to be clearly roughened.

Therefore, the amount of burnt plating to be electrodeposited in this basic plating step is 300 mg / m as a converted thickness (hereinafter simply referred to as “converted thickness”) when plating is performed on a completely smooth and flat surface. ^The amount of electrodeposition should be about ^{2 to} 600 mg / m ² . When it is less than 300 mg / m ² , it cannot be said that a nucleus for sufficiently roughening has been formed, and even if an additional plating process described later is performed, a good browning surface cannot be formed. On the other hand, when it exceeds 600 mg / m < ² >, if the additional plating process mentioned later is performed, a roughening process will advance too much and the browning process surface which is easy to powder-off will be formed.

The conditions for the burnt plating here are not particularly limited, and are determined in consideration of the characteristics of the production line. For example, if a copper sulfate-based solution is used, the concentration is 5 to 20 g / l copper, 50 to 200 g / l sulfuric acid, and other additives (α-naphthoquinoline, dextrin, glue, thiourea, etc.), liquid For example, the temperature is 15 to 40 ° C. and the current density is 10 to 50 A / dm ² .

Step b: This step is an additional plating treatment step in which the surface of the copper foil subjected to the basic plating treatment is subjected to one or more additional plating treatments using a copper sulfate-based plating solution under burn plating conditions. The burn plating conditions in this additional plating process are as follows: The same conditions may be adopted as in step a. Since there are nuclei that will form irregularities on the surface of the copper foil in step a. It is preferable to reduce the concentration to less than half that of the case in order to prevent current concentration on the underlying nucleus and prevent unnecessary abnormal precipitation. In other words, the current density (Ib) used when performing the burn plating in the step b is 50% or less of the current density, compared with the current density (Ia) used when performing the burn plating in the step a.

  Here, as described in “one or more additional plating processes”, it is also possible to perform two or more times of plating processes. However, the plating process surface formed by the basic plating process and the additional plating process at this time does not form a concavo-convex state that is visibly roughened, but covers the surface to be plated uniformly and is somewhat light. It is only necessary to create a roughened state. Therefore, it should be noted that it is necessary to control the total current and total electrolysis time of the basic plating process and the additional plating process in order to create a light roughened state.

Based on the amount of plating on the above-mentioned basic plating process, proper amount of deposition of an additional plating step, as the conversion thickness should be between 50mg ^/ m ² ~300mg / m 2 about electrodeposition amount. In the case of less than 50 mg / m ² , an appropriate uneven shape cannot be imparted to the surface nucleated in step a, and a good browning surface cannot be obtained. On the other hand, when it exceeds 300 mg / m ² , the nucleus growth formed in the step a becomes excessive, and a browned surface that is easy to fall off is formed.

Process c: This process is a coating plating process in which the copper foil surface that has been subjected to burnt plating in the processes a and b is subjected to a plating process under a smooth plating condition using a copper plating solution. The coating plating process is a plating process for smoothing the surface roughened in the process a and the process b, and is a process for uniformly depositing copper so as to cover the burnt surface. Therefore, it is possible to use all of the copper electrolyte that can be smoothly plated with copper. The smooth plating conditions are not particularly limited and are determined in consideration of the characteristics of the production line. For example, if a copper sulfate-based solution is used, the conditions are copper 50 to 80 g / l, sulfuric acid 50 to 150 g / l, liquid temperature 40 to 50 ° C., and current density 10 to 50 A / dm ^2. .

However, electrolysis time, so that is not too smooth roughened shape by burnt plating, as the conversion thickness when formed into a complete and plating the smooth and flat ^{surface, 5g / m 2 ~10g / m} 2 about Should be the amount of electrodeposition. In the case of less than 5 g / m ² , the effect of smoothing the surface roughened in step a and step b cannot be obtained. On the other hand, when it exceeds 10 g / m ² , 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 (hereinafter referred to as “finish plating treatment”) for finishing the copper foil surface brown by using the copper plating solution on the surface after completion of the step c and smooth plating treatment under the condition of burnt plating. This is a finish plating process step. In this process, the difference between the burn plating and the above-described basic plating process and additional plating process is that the roughening treatment is performed using extremely fine copper grains (hereinafter referred to as “ultrafine copper grains”). It is.

In general, a copper electrolyte containing arsenic is used to form the ultrafine copper particles. An example of electrolysis conditions in this case is a copper sulfate-based solution having a concentration of 10 g / l copper, 100 g / l sulfuric acid, 1.5 g / l arsenic, a liquid temperature of 38 ° C., and a current density of 30 A / dm ² . And so on. However, in the present invention, due to the recent rise in environmental problems, a copper electrolyte solution containing 9-phenylacridine in place of arsenic is used as an additive that is less likely to affect the human body. 9-Phenylacridine plays a role similar to the role played by arsenic in the field of copper electrolysis, and enables the sizing effect of precipitated fine copper grains and uniform electrodeposition. That is, as a copper electrolyte for forming ultrafine copper grains to which 9-phenylacridine is added, the concentration is 5 to 15 g / l copper, 40 to 100 g / l free sulfuric acid, 50 to 300 mg / l 9-phenylacridine. Further, the chlorine concentration of 20 ppm to 32 ppm, the liquid temperature of 30 to 40 ° C., and the current density of 20 to 40 A / dm ² are within a range in which an extremely stable electrolytic operation can be performed. More preferably, copper 10-15 g / l, free sulfuric acid 40-70 g / l, 9-phenylacridine 100-200 mg / l, chlorine concentration 25 ppm-30 ppm, liquid temperature 30-40 ° C., current density 20-40 A / dm ² Range. This range is the most excellent in operational stability and solution stability as a plating solution, and the production yield of the surface-treated copper foil according to the present invention is increased.

Step e: This step is a washing / drying step in which each of the above steps is washed with water and dried to obtain a browned surface-treated copper foil. Washing with water and drying may be carried out according to a regular method, and there are no special conditions. However, the rinsing referred to here simply means final rinsing, and the rinsing that can be considered within a common sense range should be provided as appropriate so that the solution of the previous process is not brought into the subsequent process between each process. Please specify.

(Method 2 for producing a surface-treated copper foil having a browned surface)
This manufacturing method is a manufacturing method of the browning surface treatment copper foil provided with each process of the process a-the process f shown below.

Step a: A basic plating treatment step of applying a first plating treatment (hereinafter referred to as “basic plating treatment”) to make the surface of the copper foil brown using a copper sulfate plating solution under a burn plating condition.
Step b: An additional plating treatment step of performing one or more additional plating treatments on the surface of the copper foil that has been subjected to the basic plating treatment, using a copper sulfate-based plating solution under burn plating conditions.
Step c: A covering plating step in which the copper foil surface that has been subjected to burnt plating in the steps a and b is plated using a copper sulfate plating solution under smooth plating conditions.
Step d: Plating treatment for finishing the copper foil surface brown (hereinafter referred to as “finish plating treatment”) using the copper sulfate-based plating solution on the surface subjected to the smooth plating treatment after the completion of the step c, under the condition of burnt plating. .) Finish plating process.
Step e: A rust prevention treatment step for carrying out a rust prevention treatment on the surface of the copper foil that has been browned by the above steps.
Step f: Washing / drying step after completion of each of the steps described above, followed by washing with water and drying to obtain a browned surface-treated copper foil.

  As is clear from the above steps, the manufacturing method 1 is a step in which a rust prevention treatment step is added. Therefore, only the rust prevention treatment process will be described in order to avoid redundant description.

In the rust-proofing process, the browning surface is not discolored, the etching removal with the copper etching solution is easy, and at the same time, the surface of the surface-treated copper foil is prevented from being oxidized and corroded. The method used for the rust prevention treatment may be any of organic rust prevention using benzotriazole, imidazole or the like, or inorganic rust prevention using zinc, chromate, zinc alloy or the like. What is necessary is just to select the rust prevention according to the intended purpose of the surface-treated copper foil. In the case of organic rust prevention, it is possible to employ techniques such as dip coating, shower ring coating, and electrodeposition method with an organic rust preventive. In the case of inorganic rust prevention, it is possible to use a method of depositing a rust-preventive element on the surface of the surface-treated copper foil by electrolysis, or other so-called substitution deposition methods. For example, a zinc pyrophosphate plating bath, a zinc cyanide plating bath, a zinc sulfate plating bath, or the like can be used for the zinc rust prevention treatment. For example, in the case of a zinc pyrophosphate plating bath, the concentration is 5 to 30 g / l of zinc, 50 to 500 g / l of potassium pyrophosphate, the liquid temperature is 20 to 50 ° C., the pH is 9 to 12, and the current density is 0.3 to 10 A / dm ^2. And so on.

Moreover, what carries out a plating process using a zinc-nickel alloy plating solution or a zinc-cobalt alloy plating solution as inorganic rust prevention which does not affect the color tone of the browning surface of the surface treatment copper foil which concerns on this invention is preferable. 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.

  Furthermore, in order to enhance the rust prevention 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, better corrosion resistance can be obtained. Is possible. That is, the chromate treatment may be performed after the above-described rust prevention treatment layer is formed. In this chromate treatment step, either a substitution treatment in which a chromate solution is brought into contact or an electrolytic chromate treatment in which a chromate film is formed by electrolysis in a chromate solution may be adopted. 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 browning surface is obtained by washing with water and drying.

  The surface-treated copper foil provided with the browning treatment surface according to the present invention described above has no powder fall off from the browning treatment surface, and has a good brown color that is extremely uniform and has no color unevenness. The browning treatment layer can be removed by an ordinary 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.

  In addition, the manufacturing method of the surface-treated copper foil according to the present invention is capable of efficiently forming a browning treatment surface on the surface of the copper foil by adopting an unprecedented multistage copper burn plating method. The variation in the color tone of the surface-treated copper foil provided with the treated surface could be made extremely small.

  Below, the surface treatment copper foil provided with the browning process surface mentioned above is manufactured, and suppose that the result of having manufactured the electromagnetic wave shielding electroconductive mesh using copper etching liquid is shown.

  In this embodiment, an electrolytic copper foil that has not been subjected to roughening treatment is used, a browning treatment is performed on the glossy surface to produce a surface-treated copper foil, and an electromagnetic shielding conductive mesh shape is experimentally produced by an etching method. The etching performance was confirmed.

  In this embodiment, a very low profile copper foil having a nominal thickness of 10 μm obtained by electrolyzing a copper sulfate solution was used. Then, the electrolytic copper foil was immersed in this solution for 30 seconds using a diluted sulfuric acid solution having a sulfuric acid concentration of 150 g / l and a liquid temperature of 30 ° C. to clean the surface. Hereinafter, each process will be described.

<Manufacture of surface-treated copper foil>
Step a: Here, a copper sulfate-based plating solution is used on the glossy surface (Ra = 0.22 μm, Rz = 1.54 μm) of the belly low profile copper foil that has not been subjected to roughening treatment, under the condition of burnt plating. The basic plating treatment was performed to make the surface of the copper foil brown.

The basic plating treatment conditions used at this time were a copper sulfate solution, and electrolysis was performed under the conditions of a burnt plating with a copper concentration of 18 g / l, a free sulfuric acid concentration of 100 g / l, a liquid temperature of 25 ° C., and a current density (Ia) of 10 A / dm ^2. It was done by doing. As a result, the burn plating performed in this basic plating process only formed nuclei for forming a certain degree of irregularities on the surface of the copper foil, and the electrodeposition amount was 300 mg / m ² in terms of converted thickness.

Step b: In this additional plating treatment step, the surface of the copper foil subjected to the basic plating treatment was subjected to a single plating treatment using a copper sulfate-based plating solution under burnt plating conditions. The additional plating treatment conditions at this time are as follows. A copper sulfate solution having the same concentration and temperature as in Example 1 was used, but the current density (Ib) employed when the burnt plating was performed was set to 1.5 A / dm ^{2 at} which the current density was 15% of Ia. In this way, current concentration on the nuclei formed on the surface of the copper foil was prevented, and unnecessary abnormal precipitation was prevented. The electrodeposition amount in this additional plating step was an electrodeposition amount of 50 mg / m ² as a converted thickness.

Step c: In this covering plating treatment step, the copper foil surface subjected to burnt plating in Step a and Step b was plated under a smooth plating condition using a copper plating solution. In this coating plating process, electrolysis was performed using a copper sulfate solution under smooth plating conditions of a copper concentration of 65 g / l, a free sulfuric acid concentration of 150 g / l, a liquid temperature of 45 ° C., and a current density of 15 A / dm ² . In this way, the surface roughened in step a and step b was smoothed. The converted thickness of smooth plating at this time was 4 g / m ² .

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

The following copper sulfate solution to which 9-phenylacridine was added was used for the formation of the ultrafine copper particles. As the copper electrolyte and electrolysis conditions, the copper concentration was 13 g / l, free sulfuric acid 50 g / l, 9-phenylacridine 150 mg / l, chlorine concentration 28 ppm, liquid temperature 35 ° C., and current density 24 A / dm ² was used. . The electrodeposition amount in the finish plating process was 300 mg / m ² as the converted thickness.

Step e: In this washing / drying step, the above-mentioned step d. After the completion of the above, it is washed by showering with pure water sufficiently, staying in a drying furnace with an atmospheric temperature of 150 ° C. for 4 seconds from an electric heater, draining the water, and giving a browned surface with a very good color tone. The surface-treated copper foil provided was obtained. In addition, the water washing between processes was provided suitably so that the solution of a front process might not be brought into a back process between not only the water washing said here but between each process.

<Physical properties of surface-treated copper foil>
As a result of observing the cross section of the surface-treated copper foil provided with the browning treatment surface obtained through the above steps with a FIB apparatus, the cross section shown in FIG. 1 is obtained, and the cross-sectional height (d ) Was 80 nm, the a value in the Lab color system of the browned surface was 3.5, and the glossiness [Gs (60 °)] was 2.8. Moreover, the powder fall in the tape test by sticking an adhesive tape on the browning surface and peeling it off was not confirmed.

<Manufacture of electromagnetic shielding mesh for plasma display>
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 a dry film on the browning 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 pattern.

  Then, using an iron chloride etchant that is a copper etchant, copper etching was performed from the browned 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.

  In this example, step d. And step e. The only difference from Example 1 is that a rust prevention treatment step is provided between the two. Therefore, the process a, the process b, the process c, and the process d are the same as those in the first embodiment, and a duplicate description is avoided, and the process e. Only the rust prevention treatment process will be described in detail.

Step e. : In this rust prevention treatment step, a zinc-nickel alloy plating solution was used for plating to form a zinc-nickel alloy layer on both sides. 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.

Step f: This washing / drying step is the same as step e. Corresponding to step e. After the completion of the step, the surface-treated copper foil was sufficiently washed with water, dried by heating, and provided with a browned surface. The details are the same as in Example 1.

<Physical properties of surface-treated copper foil>
As a result of observing the cross-section of the surface-treated copper foil provided with the browning treatment surface obtained through the above steps with a FIB apparatus, the same cross-section as shown in FIG. 1 is obtained, and the cross-sectional height of the browning treatment surface is The a value in the Lab color system of the browned surface was 3.6 nm, and the glossiness [Gs (60 °)] was 2.6. Moreover, the powder fall in the tape test by sticking an adhesive tape on the browning surface and peeling it off was not confirmed.

<Manufacture of electromagnetic shielding mesh for plasma display>
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, even if a rust preventive layer was present, the etching operation was not hindered and there was no etching residue, and very good etching was performed.

  In Example 1, the blackened surface was formed on the glossy surface of the very low profile copper foil having a nominal thickness of 10 μm, which is an electrolytic copper foil. In this embodiment, the surface on which the blackened surface was formed on the rough surface side. A treated copper foil was produced. First, as in Example 1, the electrolytic 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. Hereinafter, each process will be described.

<Manufacture of surface-treated copper foil>
Step a: Here, a copper sulfate-based plating solution is used on the rough surface (Ra = 0.35 μm, Rz = 2.32 μm) of the very low profile copper foil that has not been subjected to the roughening treatment, under the condition of burnt plating. The basic plating treatment was performed to make the surface of the copper foil brown. The surface roughness of the rough surface of this very low profile copper foil was such a low profile surface that there was no problem even if it was a glossy surface. Hereinafter, step a (basic plating treatment step), step b (additional plating treatment step), step c. Through the (coating plating process), the process d (finish plating process), and the process e (cleaning / drying process), a surface-treated copper foil having a browned surface was obtained.

<Physical properties of surface-treated copper foil>
As a result of observing the cross-section of the surface-treated copper foil provided with the browning treatment surface obtained through the above steps with a FIB apparatus, the same cross-section as shown in FIG. 1 is obtained, and the cross-sectional height of the browning treatment surface is The a value in the Lab color system of the browned surface was 3.6 nm, and the glossiness [Gs (60 °)] was 1.2. Moreover, the powder fall in the tape test by sticking an adhesive tape on the browning surface and peeling it off was not confirmed.

<Manufacture of electromagnetic shielding mesh for plasma display>
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, even if a rust preventive layer was present, the etching operation was not hindered and there was no etching residue, and very good etching was performed.

  In Example 2, the blackened surface was formed on the glossy surface of the very low profile copper foil having a nominal thickness of 10 μm, which is an electrolytic copper foil. In this embodiment, the surface on which the blackened surface was formed on the rough surface side. A treated copper foil was produced. First, using the procedure of Example 1 as in Example 2, the surface of the electrolytic copper foil was cleaned. Hereinafter, each process will be described.

<Manufacture of surface-treated copper foil>
Here, in the same manner as in Example 1, the rough surface (Ra = 0.35 μm, Rz = 2.32 μm) of the very low profile copper foil not subjected to the roughening treatment as in Example 3 was used. Step a (basic plating treatment step), step b (additional plating treatment step), step c. (Coating plating process) and d (finish plating process) were performed. And unlike Example 3, the process e. (Rust prevention treatment process) is added, and the process f. Through the (cleaning / drying step), a surface-treated copper foil having a browned surface was obtained. Step e. In the (rust prevention treatment step), a zinc-nickel alloy layer was formed by the same procedure as in Example 2. Therefore, since the above process was demonstrated in the said Example, the overlapping description shall be abbreviate | omitted.

<Physical properties of surface-treated copper foil>
As a result of observing the cross-section of the surface-treated copper foil provided with the browning treatment surface obtained through the above steps with a FIB apparatus, the same cross-section as shown in FIG. 1 is obtained, and the cross-sectional height of the browning treatment surface is The a value in the Lab color system of the browned surface was 3.8, and the glossiness [Gs (60 °)] was 1.5. Moreover, the powder fall in the tape test by sticking an adhesive tape on the browning surface and peeling it off was not confirmed.

<Manufacture of electromagnetic shielding mesh for plasma display>
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, even if a rust preventive layer was present, the etching operation was not hindered and there was no etching residue, and very good etching was performed.

Comparative Example 1

  In this comparative example, the process d. The copper concentration of the copper sulfate solution used in Example 1 was lowered to remove the optimum conditions, thereby forming ultrafine copper particles. Therefore, step d. I will explain only about.

Step d: In this finish plating step, the copper concentration of the following copper sulfate solution to which 9-phenylacridine used in Example 1 was added was 8 g / l. And the electrodeposition amount in this finish plating process was set to 300 mg / m ² as the equivalent thickness as in Example 1.

<Physical properties of surface-treated copper foil>
As a result of observing the cross section of the surface-treated copper foil provided with the browning treatment surface obtained through the above steps with a FIB apparatus, the cross section shown in FIG. 2 is obtained, and the cross-sectional height (d) of the browning treatment surface is obtained. The a value in the Lab color system of the browned surface was 3.6, and the glossiness [Gs (60 °)] was 2.6. When compared with the above example, as can be seen from the comparison between FIG. 1 and FIG. 2, it can be seen that the processed bumps by the finish plating treatment are abnormally grown and the surface causes powder falling. In addition, color unevenness was observed in the same surface of the browning surface. Moreover, powder fall was confirmed by the tape test by sticking an adhesive tape on the browning surface and peeling it off.

<Manufacture of electromagnetic shielding mesh for plasma display>
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, although there was no hindrance to the etching operation even if a rust-proofing layer was present, the browned surface of the surface-treated copper foil obtained in this comparative example was easily rubbed during handling. It was difficult to maintain our browning surface until the end of the etching process.

  The surface-treated copper foil provided with the browning surface according to the present invention has a browning surface excellent in scratch resistance with no color unevenness, no powder falling off from the blackening surface, and normal copper etching Etching using a liquid is possible, and a high-quality black mask can be formed by using it for an electromagnetic wave shielding conductive mesh of a front panel of a plasma display panel. Moreover, by supplying as a surface-treated copper foil having a browning surface, the blackening step in the front panel manufacturing process can be omitted.

  In addition, in forming the browning surface, the surface-treated copper foil according to the present invention can be manufactured with a high yield by adopting a manufacturing method in which a multi-step copper burn plating method is adopted, and smooth plating and finish burn plating are performed. Therefore, the production cost can be reduced.

The figure which showed typically the cross-sectional layer structure of the surface treatment copper foil provided with a browning process surface. The figure which showed typically the cross-sectional layer structure of the surface treatment copper foil provided with a browning process surface.

Explanation of symbols

1 Surface-treated copper foil 2 Browning surface

Claims (10)

A copper foil provided with a browning surface formed by copper plating performed in multiple stages,
The browning surface-treated copper foil according to claim 1, wherein a cross-sectional height of the browning surface is 150 nm or less. The browning surface-treated copper foil according to claim 1, wherein the browning surface has an a value in the Lab color system of 4.0 or less. The browning surface-treated copper foil according to claim 1 or 2, wherein the browning surface is provided with a rust-proofing layer. The browning-treated surface is obtained by forming the browning-treated surface on the glossy surface of an electrolytic copper foil or the surface of a rolled copper foil, and the glossiness [Gs (60 °)] is 10 or less. The browning surface-treated copper foil in any one of Claims 1-3. The browning treatment surface is obtained by forming the browning treatment surface on a rough surface of an electrolytic copper foil, and has a gloss [Gs (60 °)] of 3 or less. The browning surface-treated copper foil in any one. It is a manufacturing method of the browning surface treatment copper foil in any one of Claims 1-5, Comprising: Each process of the following process a-process e is provided, The browning surface treatment copper foil characterized by the above-mentioned. Production method.
Step a: A basic plating treatment step of applying an initial plating treatment (hereinafter referred to as “basic plating treatment”) for making the surface of the copper foil brown using a copper sulfate-based plating solution under burn plating conditions.
Step b: An additional plating treatment step in which the surface of the basic plated copper foil is subjected to one or more additional plating treatments using a copper sulfate-based plating solution under burn plating conditions.
Step c: A coating plating step in which the copper foil surface that has been burnt-plated in Steps a and b is plated using a copper sulfate plating solution under smooth plating conditions.
Step d: Plating treatment for finishing the copper foil surface brown (hereinafter referred to as “finish plating treatment”) using a copper sulfate-based plating solution on the surface that has been subjected to the smooth plating treatment after the completion of the step c. .) Finish plating process.
Step e: Washing / drying step after completion of each step described above, followed by washing with water and drying to obtain a browned surface-treated copper foil. It is a manufacturing method of the browning surface treatment copper foil in any one of Claims 3-5, Comprising: Each process of the following process a-process f is provided, The browning surface treatment copper foil characterized by the above-mentioned. Production method.
Step a: A basic plating treatment step of applying an initial plating treatment (hereinafter referred to as “basic plating treatment”) for making the surface of the copper foil brown using a copper sulfate-based plating solution under burn plating conditions.
Step b: An additional plating treatment step in which the surface of the basic plated copper foil is subjected to one or more additional plating treatments using a copper sulfate-based plating solution under burn plating conditions.
Step c: A coating plating step in which the copper foil surface that has been burnt-plated in Steps a and b is plated using a copper sulfate plating solution under smooth plating conditions.
Step d: Plating treatment for finishing the copper foil surface brown (hereinafter referred to as “finish plating treatment”) using a copper sulfate-based plating solution on the surface that has been subjected to the smooth plating treatment after the completion of the step c. .) Finish plating process.
Step e: A rust prevention treatment step for carrying out a rust prevention treatment on the surface of the copper foil that has been browned by the above steps.
Step f: A washing / drying step after completion of each of the above steps, followed by washing with water and drying to obtain a browned surface-treated copper foil. 7. The current density (Ib) employed when performing the burn plating in the step b is 50% or less of the current density of the current Ia (Ia) employed when performing the burn plating in the step a. Item 8. A method for producing a browned surface-treated copper foil according to Item 7. The copper plating solution used for the burn plating in step d has a copper concentration of 5 to 15 g / l, free sulfuric acid 40 to 100 g / l, 9-phenylacridine 50 to 300 mg / l, and a chlorine concentration of 20 ppm to 32 ppm. The manufacturing method of the browning surface treatment copper foil in any one of Claims 6-8. An electromagnetic wave shielding conductive mesh for a front panel of a plasma display using the browned surface-treated copper foil according to any one of claims 1 to 5.