KR102116928B1 - Blackened surface-treated copper foil, method for manufacturing blackened surface-treated copper foil, copper-clad laminate and flexible printed circuit board - Google Patents

Abstract

A printed wiring board having a blackened surface capable of improving CCD visibility in terminal connection processing and AOI inspection accuracy of the flexible printed wiring board, having a suitable roughness suitable for manufacturing a flexible printed wiring board, and having good etching properties. It aims at provision of copper foil for dragons. To achieve this object, in the surface-treated copper foil provided with a roughened surface, the roughened surface has a maximum height difference (Wmax) of curvature of 1.2 µm or less, and a lightness L of the L * a * b * colorimetric system. * A blackened surface-treated copper foil or the like for manufacturing a flexible printed wiring board, which is characterized in that it is a black roughened surface having a color tone of 30 or less, is employed.

Description

Blackened surface-treated copper foil, manufacturing method of blackened surface-treated copper foil, copper clad laminates and flexible printed wiring boards BOARD}

The present application relates to a blackened surface-treated copper foil, a method for producing a blackened surface-treated copper foil, a copper clad laminate obtained using a blackened surface-treated copper foil, and a flexible printed wiring board. In particular, the present invention relates to a surface-treated copper foil subjected to a fine roughening treatment to blacken the surface of the copper foil.

Conventionally, as an automatic appearance inspector of a printed wiring board, AOI (Automatic Optical Inspecter) has been widely used for automatic inspection. AOI transmits light from the rear surface of the printed wiring board, captures light passing through the printed wiring board, and reads the circuit pattern to deviate from the specification, resulting in pattern loss, pattern thinning, pinholes, scratches, shorts, and patterns It is a device that detects circuit defects such as thickening, copper residue, protrusions, and contamination.

In addition, recently, when connecting the liquid crystal display module and the flexible printed wiring board with an anisotropic conductive film (ACF), the connection terminal of the liquid crystal display module and the connection terminal of the flexible printed wiring board are used with a CCD camera from the circuit back of the flexible printed wiring board. Alignment is being done. Therefore, it is preferable that a clear contrast exists as a color tone between the circuit back surface and the resin film. Therefore, in general, it is required that the adhesive surface of the copper foil used for circuit formation with the resin film is good black. On the other hand, good visibility is required for the resin film exposed by etching removal of the copper foil of the flexible printed wiring board. This visibility (hereinafter simply referred to as "CCD visibility") depends on the haze of the resin film exposed by etching removal of the copper foil of the flexible printed wiring board.

Therefore, in the above-mentioned use, in order to improve the CCD visibility of the flexible printed wiring board and the inspection accuracy of the AOI, "the resin film exposed by etching and removing the copper foil of the flexible printed wiring board is excellent in light transmittance" and "circuit back The difference between the color tone of and the color tone of the resin film is clear. That is, the former requires the property that the value of haze of the exposed resin film is low by etching and removing the copper foil of the copper clad laminate, and the uneven shape where the adhesive surface of the copper foil remains on the resin film surface. It is a characteristic that depends. In addition, the latter is a characteristic dependent on the color tone provided by the adhesive surface of the copper foil with the resin film. As a copper foil which satisfies these required characteristics, the surface-treated copper foil disclosed in the following patent documents 1 and 2 is mentioned.

Patent Literature 1 aims to provide a surface-treated copper foil capable of forming a fine pitch circuit and having good adhesive strength after heating as a copper foil used for forming a copper layer of a flexible copper clad laminate. In the copper foil for forming a copper layer on the surface of the base layer, the copper foil is a surface treatment layer in any one of a state in which a cobalt layer or a cobalt layer and a nickel-zinc alloy layer are laminated on an adhesive surface with a polyimide resin layer. It is disclosed that the use of a surface-treated copper foil for the production of a flexible copper clad laminate is provided, and is targeted at a non-roughened surface-treated copper foil. Paragraph 0034 of the specification of this patent document 1 says, "In addition, it is preferable that the glossiness [Gs (60 °)] is 70 or more on the adhesive surface of the said surface-treated copper foil with a polyimide resin base material. This is to ensure good fine pitch circuit forming ability and good light transmittance required for optical automatic inspection (AOI inspection). For example, ... (omitted in the middle) ... In the present invention, although the glossiness [Gs (60 °)] is said to be 70 or more, when the glossiness is less than 70, good fine pitch circuit forming ability is not obtained, and upon inspection by an optical automatic inspection device (AOI device) It is also difficult to secure the good light transmittance required for this. ”

It is also conceivable to use copper foil used for forming a black mask of the plasma display panel disclosed in Patent Document 2. This is because the copper foil for this purpose uses a color as close to black as possible to the color tone of the adhesive surface of the copper foil. In this patent document 2, the copper foil used for manufacture of the conductive mesh used for electromagnetic wave shielding of a plasma display panel is disclosed, and the surface of the blackened surface-treated copper foil disclosed in patent document 2 meets the request of black mask formation. It is a nickel-based blackening-treated surface or a cobalt-based blackening-treated surface. When a flexible printed wiring board is manufactured using the copper foil disclosed in this patent document 2, the copper foil of the flexible printed wiring board is removed, the haze of the exposed resin film is low, the light transmittance is excellent, and the flexible printed wiring board It is thought that the difference in color tone required for AOI can be satisfied satisfactorily.

Japanese Patent Application Publication No. 2008-132757 W02007 / 007870 Publication

However, since the surface-treated copper foil for manufacturing a flexible copper clad laminated sheet disclosed in Patent Document 1 is an uncoated surface-treated copper foil, it has a flatness that does not roughen the surface of the resin film of the flexible printed wiring board, but this surface-treated copper foil When the adhesive surface is excessively flat, wrinkles and bubbles are likely to be generated at the adhesive interface when the surface-treated copper foil is bonded to the resin film. Therefore, it is required that the surface-treated copper foil used for a flexible copper clad laminate has a suitable roughness that is less likely to cause wrinkles and bubbles, and a flat adhesive surface.

Further, even if the blackened surface of the blackened surface-treated copper foil disclosed in Patent Literature 2 is used in the production of a flexible copper clad laminate, as described above, when bonding the surface-treated copper foil and the resin film, wrinkles are formed on the adhesive interface. Or bubbles are likely to occur. In addition, the blackening surface of the blackening surface-treated copper foil disclosed in Patent Literature 2 is a nickel-based blackening treatment surface or a cobalt-based blackening treatment surface, and etching with a copper etching solution tends to be difficult. Therefore, at the time of circuit formation, the time for overetching with a copper etching solution becomes long, so that the etching of the copper portion becomes excessive, and it is difficult to form a fine pitch circuit with an excellent etching factor. Further, even if it is considered that a sufficient over-etching time has been set, it is not preferable because nickel or cobalt remains between circuits, the probability of migration increases, and the reliability of the product decreases.

From these contents, this application is equipped with the blackening surface which can improve CCD visibility and AOI detection precision equivalent to the copper foil disclosed in patent document 2, and has the appropriate roughness suitable for manufacture of a flexible printed wiring board, Another object is to provide a copper foil for a printed wiring board having good etching properties.

Therefore, the inventors of the present invention contemplated solving the above-mentioned problems by using the following blackened surface-treated copper foil for manufacturing flexible printed wiring boards.

Blackened surface-treated copper foil: The blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application is a surface-treated copper foil provided with a black roughened surface, wherein the black roughened surface has a maximum height difference (Wmax) of curvature. It is characterized in that it has a color tone of less than or equal to 1.2 µm and a brightness L * of L * a * b * color system of 30 or less.

It is preferable that the black roughened surface of the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application is roughened by adhering copper particles having a particle diameter of 10 nm to 250 nm.

It is preferable that 400 to 2500 copper particles are attached to the black roughened surface of the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application in a region of 3 µm × 3 µm.

The black roughened surface of the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application preferably has an average roughness Ra of 0.5 µm or less.

It is preferable that the said black roughening surface of the blackened surface-treated copper foil for manufacture of a flexible printed wiring board which concerns on this application has a copper friction coefficient of 0.50 or more.

Manufacturing method of blackened surface-treated copper foil: The manufacturing method of the blackened surface-treated copper foil for manufacture of a flexible printed wiring board which concerns on this application is the manufacture of the blackened surface-treated copper foil for manufacture of the flexible printed wiring board mentioned above, and On the surface where the maximum height difference (Wmax) of the bend is 1.2 µm or less, the copper concentration is 10 g / L to 20 g / L, the free sulfuric acid concentration is 15 g / L to 100 g / L, and the 9-phenylacridine concentration is 100 mg / L to It is characterized by performing black roughening by attaching fine copper particles using a copper electrolytic solution for black roughening having a concentration of 200 mg / L and a chlorine concentration of 20 mg / L to 100 mg / L.

In the method for producing a blackened surface-treated copper foil for flexible printed wiring board manufacturing, in a black electrolytic solution for black roughening at a solution temperature of 20 ° C to 40 ° C, the copper foil is polarized as a cathode, and the current density is 30A / dm ^{2 to} 100A / It is preferable to form fine copper particles on the surface of the copper foil by electrolysis by dm ² .

Copper clad laminated board: The copper clad laminated board for manufacturing a flexible printed wiring board according to the present application is characterized by being obtained by using the blackened surface-treated copper foil for manufacturing the flexible printed wiring board described above.

Flexible printed wiring board: The flexible printed wiring board according to the present application is characterized in that it is obtained by using a copper clad laminate for manufacturing the flexible printed wiring board described above.

The blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application has a blackened surface excellent in CCD visibility and AOI inspection accuracy. In addition, the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application has good etching properties because fine roughened particles are formed of copper. Therefore, it is possible to shorten the time of over-etching in the etching at the time of circuit formation, and it is possible to form a fine pitch circuit having an extremely good etching factor.

1 is a scanning electron microscope observation image of a roughened form of a blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application (Example 1).
2 is a scanning electron microscope observation image observing the roughened surface of a conventional surface-treated copper foil (Comparative Example 1).
Fig. 3 is a scanning electron microscope observation image observing the roughened surface of a conventional surface-treated copper foil (Comparative Example 2).
Fig. 4 is a scanning electron microscope observation image observing the roughened surface of a conventional surface-treated copper foil (Comparative Example 3).

Hereinafter, each form of "blackening surface-treated copper foil", "the manufacturing method of blackening surface-treated copper foil", "copper clad laminated board", and "flexible printed wiring board" concerning this application is demonstrated.

Blackened surface-treated copper foil: The blackened surface-treated copper foil for manufacturing flexible printed wiring boards according to the present application has a maximum height difference (Wmax) of curvature of 1.2 µm or less, and a lightness L * of L * a * b * colorimetric system is 30. It is characterized by comprising a black rough surface of the following color tone.

One feature of the black roughened surface of the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application is that the maximum height difference (Wmax) of bending is 1.2 µm or less. The term "maximum height difference of bending (Wmax)" is the maximum value of the high difference in waveform data extracted by filtering waveform data related to bending from information on irregularities of a sample surface obtained using a three-dimensional surface structure analysis microscope. (The sum of the maximum peak height of the waveform and the maximum valley depth). When a flexible printed wiring board is manufactured using a surface-treated copper foil having a black rough surface having a maximum roughness difference (Wmax) of greater than 1.2 µm, the copper foil of the flexible printed wiring board is removed by etching. The turbidity (Haze) increases, and the CCD visibility and AOI inspection accuracy decrease. And, in order to make this turbidity (Haze) a stable low value, it is more preferable to set the maximum height difference (Wmax) of bending to 1.0 µm or less.

In addition, the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application is also characterized in that the black roughened surface has a color tone having a brightness L * of 30 or less in the L * a * b * color system defined in JIS Z8729. When the lightness L * of the L * a * b * colorimetric system exceeds 30, the particle size of the roughened particles becomes large, and the copper foil of the flexible printed wiring board is etched away, so that the haze of the exposed resin film is increased. Further, when the lightness L * of the L * a * b * colorimetric system exceeds 30, the contrast of the color tone of the circuit back surface formed using this blackened surface-treated copper foil and the color of the resin film is lowered, and thus the CCD visibility. This decreases, and the inspection accuracy of AOI also tends to decrease. And when the brightness L * of the L * a * b * color system is 20 or less, the haze of the said resin film stably falls. In addition, when the lightness L * of the L * a * b * colorimetric system is 15 or less, the contrast of the color tone on the circuit back side and the color tone with the resin film is clarified together with the haze of the resin film, further improving the CCD visibility. do.

It is preferable that the black roughening surface of the blackened surface-treated copper foil for manufacture of a flexible printed wiring board which concerns on this application adheres copper particles with a particle diameter of 10 nm to 250 nm. Here, the lower limit of the particle diameter of the copper particles is set to 10 nm. However, although it is not meant to actively exclude the roughened particles having a particle diameter of less than 10 nm, if the roughened particles become too fine, there is a possibility that the anchor effect on the resin film is lowered. On the other hand, when the particle diameter of the roughened particles exceeds 250 nm, the copper foil of the copper clad laminate prepared by using the surface-treated copper foil is etched away to increase the haze of the exposed resin film portion, CCD visibility and The inspection accuracy of AOI also decreases, which is not preferable. The shape of the copper particles is not particularly limited, but it is preferable that the copper particles are substantially spherical. This is because if the copper particles are approximately spherical, powder fall can be prevented.

In addition, it is preferable that 400 to 2500 copper particles are attached to the black roughened surface of the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application in a region of 3 µm × 3 µm. When the number of adhesion of copper particles in this predetermined area is less than 400, it is difficult to make the brightness L * of the L * a * b * color system mentioned above 30 or less, which is undesirable. On the other hand, when the number of adhesion of the copper particles in a predetermined area exceeds 2500, the adhesion of the attached copper particles tends to occur, and the above-mentioned turbidity value (Haze) tends to increase. It is not preferable because visibility and AOI inspection accuracy are lowered.

The copper particles constituting the black rough surface of the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application described above are made of copper and unavoidable impurities, and do not contain an alloy component or the like that inhibits etching. desirable. If the copper particles have a composition equivalent to the copper component constituting the copper foil, the etching rate in the copper etching solution is equivalent to that of the copper foil and the copper particles, so that the process design of circuit formation conditions by etching becomes easy.

The black roughened surface of the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application preferably has an average roughness Ra of 0.5 µm or less when measured using a stylus surface roughness meter. The blackened surface-treated copper foil according to the present application has extremely low values for the average roughness. When this average roughness Ra exceeds 0.5 µm, in the etching step of forming the circuit, the time for overetching to set the roughened particles entering the resin film between the wirings so as not to remain as an etching residue is prolonged, so that the sidewall of the wiring is It is not preferable because it dissolves more than necessary and it becomes difficult to form a fine pitch circuit having a good etching factor. Moreover, it is more preferable that the said average roughness Ra is 0.3 micrometers or less. This is because the chemical resistance performance can be improved by preventing the formation of a fine pitch circuit having a good etching factor, and at the same time, erosion of the solution to the lamination surface of the surface-treated copper foil and the resin film lamination interface.

Moreover, it is preferable that the black roughening surface of the blackened surface-treated copper foil for manufacture of a flexible printed wiring board which concerns on this application has a copper friction coefficient of 0.50 or more. When the dynamic friction coefficient is less than 0.50, when the resin film and the blackened surface-treated copper foil are laminated by a roll lamination method, the black surface of the blackened surface-treated copper foil is too smooth, and the blackened surface-treated copper foil is Slippage occurs at the adhesive interface of the resin film, and wrinkles are likely to occur, making it difficult to perform good lamination. Moreover, when this dynamic friction coefficient is less than 0.50, air bubbles tend to tend to be generated at the adhesion interface between the blackened surface-treated copper foil and the resin film.

The blackened surface-treated copper foil described above is not particularly limited in terms of thickness. In addition, it is specified that the concept includes not only black surface roughening on the surface of a normal copper foil, but also black surface roughening of the copper foil surface of the copper foil with a carrier foil.

Manufacturing method of blackened surface-treated copper foil: The manufacturing method of the blackened surface-treated copper foil for manufacture of a flexible printed wiring board which concerns on this application is the manufacture of the blackened surface-treated copper foil for manufacture of the flexible printed wiring board mentioned above, and Fine copper particles are adhered to a surface having a maximum height difference (Wmax) of bending of 1.2 µm or less to perform black roughening. If the maximum height difference (Wmax) of the curvature of the adhesive surface to this resin film exceeds 1.2 µm, after black roughening, the maximum height difference (Wmax) of the curvature is less likely to be 1.2 µm or less. Then, in consideration of variations in processes in the manufacturing method of the blackened surface-treated copper foil, and the like, in order to stably set the maximum height difference (Wmax) of bending after black roughening to 1.2 µm or less, the maximum height difference of bending (Wmax) ) Is more preferably 0.8 µm or less.

As the copper foil before the black roughening used in the method for producing a blackened surface-treated copper foil described above, both the electrolytic copper foil and the rolled copper foil can be used. Further, even if the maximum height difference (Wmax) of the bending exceeds 1.2 µm, the maximum height difference (Wmax) of the bending is 1.2 µm or less by performing etching treatment, copper plating, or the like on the surface of the copper foil. You may do it. In addition, as long as the copper foil referred to herein satisfies the condition that the maximum height difference (Wmax) of the curvature of the adhesive surface to the resin film is 1.2 µm or less, it may be an uncoated copper foil or preliminarily roughened. do. The thickness of the copper foil is not particularly limited.

In performing black roughening by attaching fine copper particles to a surface having a maximum height difference (Wmax) of curvature of the copper foil of 1.2 µm or less, it is preferable to use the following copper electrolytic solution for black roughening. That is, the copper concentration is 10 g / L to 20 g / L, the free sulfuric acid concentration is 15 g / L to 100 g / L, the 9-phenylacridine concentration is 100 mg / L to 200 mg / L, and the chlorine concentration is 20 mg / L. A copper electrolytic solution for black roughening of ∼100 mg / L is used. The copper electrolytic solution for black roughening uses a sulfuric acid acidic copper electrolytic solution having a copper concentration of 10 g / L to 20 g / L and a free sulfuric acid concentration of 15 g / L to 100 g / L as a basic solution. Here, when the copper concentration is less than 10 g / L, the electrodeposition rate of the copper particles is slow, which is not preferable because it does not satisfy the industrially required productivity. On the other hand, when the copper concentration exceeds 20 g / L, it is not preferable because it approaches the smooth plating condition and becomes difficult to roughen in black in relation to the current density described later. In addition, the free sulfuric acid concentration is not preferable because, in relation to the copper concentration, when the concentration range is deviated, the conduction characteristics during electrolysis change, making it difficult to achieve good black roughening.

And in the case of the black electrolytic solution for roughening used in the manufacturing method of the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application, the 9-phenylacridine concentration is 100 mg / L to 200 mg / L. It is preferable to contain in the range. This 9-phenylacridine functions as an additive that refines the particle diameter of the copper particles that adhere and form on the surface of the copper foil, and promotes spheroidization of the particle shape. When the concentration of 9-phenylacridine in the copper electrolytic solution for black roughening is less than 100 mg / L, the effect of miniaturizing the particle size of the copper particles is difficult to obtain, and the effect of promoting the spheroidization of the particle shape is also not preferable. On the other hand, even if the concentration of 9-phenylacridine in the black electrolytic solution for roughening exceeds 200 mg / L, the effect of minimizing the particle size of the copper particles and promoting the spheroidization of the particle shape are simultaneously saturated and proportional to the amount added. It is not preferable because an effect is not obtained and a simple waste of resources is obtained.

Moreover, it is preferable to contain the chlorine concentration of the copper electrolytic solution for black roughening used in the manufacturing method of the blackened surface-treated copper foil for manufacture of flexible printed wiring board which concerns on this application in the range of 20 mg / L-100 mg / L. Do. When the chlorine concentration of the black roughening copper electrolytic solution is less than 20 mg / L, it is difficult to obtain a burning plating state for forming copper particles, and it is not preferable because roughly shaped roughened particles are not obtained. On the other hand, when the chlorine concentration of the copper roughening solution for black roughening exceeds 100 mg / L, the color tone of the black roughened surface of the blackened surface-treated copper foil tends to occur, and the spheroidization of the particle shape is good. It is not preferable because it is not performed.

When black roughening is performed on the surface of a copper foil using the black electrolytic solution for roughening described above, the copper foil is polarized as a cathode in a copper electrolytic solution having a solution temperature of 20 ° C to 40 ° C, and the current density is 30A / dm ^2, it is desirable to be delivered in ~100A / dm ^2. Here, the solution temperature is preferably in the range of 20 ° C to 40 ° C. When the solution temperature is less than 20 ° C, variations in the shape of the roughened particles to be formed tend to occur, which is not preferable. On the other hand, if this solution temperature exceeds 40 ° C, it is not preferable because the solution properties of the copper electrolytic solution for black roughening tend to occur, and stable burning plating tends to be impossible.

In addition, it is preferable that the current density at the time of performing black roughening by polarizing a copper foil as a negative electrode in a copper electrolytic solution is in the range of 30 A / dm ^{2 to} 100 A / dm ² . When this current density is less than 30 A / dm ² , it is not preferable because sufficient black roughening cannot be achieved and it becomes difficult to set the brightness L * of the black roughened screen to 30 or less. On the other hand, when the current density exceeds 100 A / dm ² , it is not preferable because the precipitation rate of fine copper particles becomes excessive, and the shape of the formed copper particles does not become a good spherical body.

Copper clad laminated board: The copper clad laminated board according to the present application is a flexible copper clad laminated board characterized by being obtained by laminating a blackened surface-treated copper foil for manufacturing a flexible printed wiring board and a resin film. As the resin film at this time, a polyimide resin film, a PET film, an aramid resin film, or the like can be used, but as long as it can be used as a resin film for a flexible printed wiring board, there is no particular limitation. In addition, for the production of the flexible copper clad laminate, a conventional lamination method, a continuous lamination method, a casting method, or the like can be adopted, and a resin layer can be formed on the surface of the blackened surface-treated copper foil. The casting method referred to herein refers to the surface of the blackened surface-treated copper foil according to the present invention, by forming a resin composition film to polyimide resin by heating, such as polyamic acid, and heating to cause a condensation reaction. This refers to a method of directly forming a polyimide resin film layer on the surface of a blackened surface-treated copper foil.

Flexible printed wiring board: This flexible printed wiring board is a resin film exposed to the melted portion of the blackened surface-treated copper foil when the blackened surface-treated copper foil according to the present application is etched from the above-described state of the copper clad laminate. Haze can be significantly reduced. The value of this turbidity (Haze) also varies depending on the type of the resin film. However, as long as the resin film used for the copper clad laminate is the same, by using the blackened surface-treated copper foil according to the present application, it is possible to obtain extremely low haze (Haze) compared to the case of using the conventional surface-treated copper foil. It becomes possible, and the CCD visibility and suitability for AOI are dramatically improved.

Example 1

In Example 1, an electrolytic copper foil having a thickness of 12 µm was prepared, black roughening, rust prevention treatment, and silane coupling agent treatment were performed to prepare a blackened surface-treated copper foil, and comparison was made with a comparative example described later. Did.

Preparation of electrolytic copper foil: A copper sulfate solution using an acidic copper sulfate solution having the composition shown below is used as a cathode, a titanium-made rotating electrode having a surface roughness Ra = 0.20 µm is used as a cathode, and DSA is used as an anode. Electrolysis was performed at a solution temperature of 45 ° C and a current density of 55 A / dm ² to obtain an electrolytic copper foil having a thickness of 12 µm. The maximum height difference (Wmax) of the curvature of the precipitation surface of this electrolytic copper foil was 0.8 µm.

Copper concentration: 80g / L

Free sulfuric acid concentration: 140g / L

Bis (3-sulfopropyl) disulfide concentration: 30mg / L

Diallyldimethylammonium chloride polymer concentration: 50mg / L

Chlorine concentration: 40mg / L

Black roughening: Of the electrode surface and the precipitation surface provided by the above-mentioned electrolytic copper foil, for the precipitation surface side, a copper electrolytic solution for black roughening having the composition shown below was used, and the solution temperature was 30 ° C and the current density was 50 A / dm ² . Electrolysis was performed under conditions, and black roughening was performed.

Copper concentration: 13g / L

Free sulfuric acid concentration: 55g / L

9-phenylacridine concentration: 140mg / L

Chlorine concentration: 35mg / L

Anti-rust treatment: When the above-mentioned black roughening was completed, anti-rust treatment was performed on both surfaces of the electrolytic copper foil after the black roughening. Here, the inorganic rust preventive of the conditions described below was employed. A pyrophosphoric acid bath was used, and zinc-nickel alloy anti-corrosive treatment was performed with potassium pyrophosphate concentration 80 g / L, zinc concentration 0.2 g / L, nickel concentration 2 g / L, liquid temperature 40 ° C., current density 0.5 A / dm ² .

Then, as the rust prevention treatment, a chromate layer was further formed on the zinc-nickel alloy rust treatment. The chromate treatment conditions at this time were performed with a chromic acid concentration of 1 g / L, pH 11, a solution temperature of 25 ° C, and a current density of 1 A / dm ² .

Silane coupling agent treatment: When the above rust prevention treatment is completed, after washing with water, the silane coupling agent treatment is immediately performed, and the silane coupling agent is adsorbed onto the antirust treatment layer on the black rough surface. As the solution at this time, pure water was used as a solvent, and a 3-aminopropyl trimethoxysilane concentration of 3 g / L was used. Then, this solution was sprayed onto a black rough surface by showering, and adsorbed. When the adsorption of the silane coupling agent was completed, moisture was finally calculated by the electric heater to obtain a blackened surface-treated copper foil having a thickness of 12 µm.

The scanning electron microscope observation image of the blackened surface-treated copper foil which concerns on this application obtained as mentioned above is shown in FIG. In addition, about the evaluated various characteristics, it shows in Table 1 so that contrast with a comparative example becomes easy.

Example 2

In Example 2, an electrolytic copper foil having a thickness of 12 µm was produced, and black roughening, antirust treatment, and silane coupling agent treatment similar to that of Example 1 were performed to produce a blackened surface-treated copper foil.

Preparation of electrolytic copper foil: As a copper electrolytic solution, a sulfuric acid acidic copper sulfate solution having a bis (3-sulfopropyl) disulfide concentration of 20 mg / L in Example 1 was used, and under the same conditions as in Example 1, thickness An electrolytic copper foil of 12 µm was obtained. The maximum height difference (Wmax) of the curvature of the precipitation surface of this electrolytic copper foil was 1.2 µm.

Using the above-mentioned electrolytic copper foil, black roughening, antirust treatment, and silane coupling agent treatment similar to that of Example 1 were performed to obtain the blackened surface-treated copper foil of Example 2. Table 1 shows various properties evaluated in order to facilitate comparison with a comparative example.

Example 3

In Example 3, using the same electrolytic copper foil as in Example 1, black roughening, antirust treatment, and silane coupling agent treatment were performed to prepare a blackened surface-treated copper foil. In the following, only black roughening different from Example 1 will be described.

Black roughening: Preliminary roughening treatment was performed on the precipitation surface side among the electrode surfaces and the precipitation surfaces of the electrolytic copper foil described above. The preliminary roughening process at this time was performed by the following two-step process.

In the first step of the preliminary roughening treatment, a copper electrolytic solution for roughening treatment having a copper concentration of 18 g / l and a free sulfuric acid concentration of 70 g / l was used, at a solution temperature of 25 ° C and a current density of 4 A / dm ² , 4 Electrolyzed for a second and washed with water. Then, in the second step, using a copper electrolytic solution having a copper concentration of 65 g / l and a free sulfuric acid concentration of 60 g / l, electrolysis was performed at a solution temperature of 45 ° C and a current density of 5 A / dm ² for 5 seconds, followed by washing with water and preliminary washing. Red roughening treatment was performed. The maximum elevation difference (Wmax) of the curvature of the precipitation surface of the electrolytic copper foil at this stage was 0.9 µm. Therefore, it is understood that the maximum height difference (Wmax) of the curvature of the precipitated surface before the preliminary roughening treatment is 0.8 µm, and the curvature is not significantly changed, and is an appropriate range of curvature.

Then, black roughening, antirust treatment, and silane coupling agent treatment were performed on the precipitated surface subjected to the preliminary roughening treatment in the same manner as in Example 1 to obtain the blackened surface-treated copper foil of Example 3. Table 1 shows various properties evaluated in order to facilitate comparison with a comparative example.

Comparative example

[Comparative Example 1]

In Comparative Example 1, a roughening treatment was performed on the precipitation surface of the electrolytic copper foil used in Example 1 in a manner different from that in Example 1. Therefore, since only the roughening process differs from Example 1, only the roughening process will be described in detail below.

Roughening treatment: In Comparative Example 1, roughening treatment was performed on the precipitated surface of the electrolytic copper foil in the following two-step process. The first step of the roughening treatment is copper electrolysis for roughening treatment with a copper concentration of 8 g / l, a free sulfuric acid concentration of 50 g / l, a 9-phenylacridine concentration of 150 mg / l, and a chlorine concentration of 50 mg / l. Using the solution, electrolysis was performed at a solution temperature of 30 ° C and a current density of 19 A / dm ² , followed by washing with water. Then, in the second step, using a copper electrolytic solution having a copper concentration of 65 g / l and a free sulfuric acid concentration of 90 g / l, electrolysis was performed at a solution temperature of 48 ° C and a current density of 15 A / dm ² , followed by washing with water and roughening treatment. Was done.

When the above-mentioned roughening treatment was completed, the rust prevention treatment similar to Example 1 and the silane coupling agent treatment were performed to obtain the surface-treated copper foil of Comparative Example 1. The scanning electron microscope observation image of the surface-treated copper foil of this comparative example 1 is shown in FIG. In addition, about the evaluated various characteristics, it shows in Table 1 so that contrast with an Example may become easy.

[Comparative Example 2]

In Comparative Example 2, the same electrolytic copper foil as in Example 1 was used, and a roughening treatment was performed on the precipitated surface similar to Example 1 in a manner different from that in Example 1. Therefore, since only the roughening process differs from Example 1, only the roughening process will be described in detail below.

Roughening treatment: In Comparative Example 2, roughening treatment was performed on the precipitated surface of the electrolytic copper foil by the following method. In the first step of the roughening treatment, using a copper electrolytic solution for roughening treatment having a copper concentration of 18 g / l and a free sulfuric acid concentration of 70 g / l, the solution temperature was 25 ° C, current density 10 A / dm ² , and energization time 10 seconds. Electrolyzed and washed with water. Then, in the second step, a copper electrolytic solution having a copper concentration of 65 g / l and a free sulfuric acid concentration of 60 g / l was used for electrolysis at a liquid temperature of 45 ° C and a current density of 15 A / dm ² for 20 seconds to perform a roughening treatment. .

When the above-mentioned roughening treatment was completed, the rust prevention treatment and silane coupling agent treatment similar to those of the example were performed to obtain the surface-treated copper foil of Comparative Example 2. The scanning electron microscope observation image of the surface-treated copper foil of this comparative example 2 is shown in FIG. In addition, about the evaluated various characteristics, it shows in Table 1 so that contrast with an Example may become easy.

[Comparative Example 3]

Comparative Example 3 used the same electrolytic copper foil as in Example 1, and applied the same roughening treatment, rust prevention treatment, and silane coupling agent treatment as in Example 1 to the electrode surface which is the opposite side of the precipitation surface used in Example 1. Was done. Therefore, since the surface of Example 1 and the roughened surface are different, the detailed description of the overlapping is omitted. The scanning electron microscope observation image of the surface-treated copper foil which concerns on this comparative example 3 is shown in FIG. In addition, about the evaluated various characteristics, it shows in Table 1 so that contrast with an Example may become easy.

[Assessment Methods]

Maximum height difference (Wmax) of bending: zygo New View 5032 (manufactured by Zygo) is used as a measuring instrument, Metro Pro Ver.8.0.2 is used for the analysis software, and a low-frequency filter is adopted for the conditions of 11 µm, and The maximum height difference (Wmax) was measured. At this time, the surface to be measured of the surface-treated copper foil was adhered to the sample table and fixed, and the field of view of 108 µm × 144 µm was selected from six points within a range of 1 cm on one side of the sample piece and measured. The average value of the maximum height difference (Wmax) of the bending was adopted as a representative value.

Brightness L *: Measured according to JIS Z8729 using Nihon Denshoku Kogyo Co., Ltd. type SE2000.

Average roughness (Ra): Measurement was made in accordance with JIS B0601 using a stylus-type surface roughness meter SE3500 (probe radius of curvature: 2 µm) manufactured by Kosaka Kyosho.

The number of adhesion of copper particles: a scanning electron microscope of an electric field emission type observed in the direction of inclination of 45 ° with respect to the black roughening surface of the blackened surface treatment copper foil according to the example and the surface roughened screen of the copper foil according to the comparative example The number of adhesion of the copper particles that can be observed in the region of 3 µm × 3 µm in the observation image (magnification: 20,000 times) was visually counted.

Dynamic friction coefficient: It was measured using a Tribore surface measuring instrument TYPE 14 manufactured by Shinto Chemical Co., Ltd. A 50-µm-thick polyimide resin film (Yuprex manufactured by Ube Kosan Co., Ltd.) was fixed to the measurement stage, and the surface-treated copper was placed so that the rough surfaces of the polyimide resin film and the surface-treated copper foil faced each other. The foil is fixed to the friction element. Then, under the conditions of a vertical load of 100 g, a moving speed of 100 mm / min, and a moving distance of 10 mm, the measurement time and the frictional resistance are output, and dynamic friction is obtained from the average value of the frictional force measured between 2 and 6 seconds during which the measured value stabilizes. Coefficients were calculated.

Haze: A copper clad laminate was produced by thermally compressing a surface-treated copper foil and a PET film. Subsequently, the surface-treated copper foil was etched off, and the remaining PET film was prepared using a haze meter NDH5000 (manufactured by Nippon Denshoku Kogyo Co., Ltd.), according to JIS-K7136 (2000) to obtain a film at 23 ° C. Turbidity (Haze: unit%) was measured in three places, and the average value was obtained.

[Comparison of Examples and Comparative Examples]

First, with reference to the drawings, the "maximum height difference (Wmax) of curvature" of Examples and Comparative Examples is prepared. It can be understood that the value of the maximum height difference (Wmax) of the bending of the comparative example is higher than the maximum height difference (Wmax) of the bending of the example, and the value of haze of these comparative examples is also higher than the example, and lacks transparency. have.

However, the maximum height difference (Wmax) of the bending of Comparative Example 2 is considered to be no significant difference compared to the maximum height difference (Wmax) of the bending of Example 2. However, looking at the value of turbidity (Haze), Example 2 is 12, whereas Comparative Example 2 is 84, it can be seen that the transparency of the resin film in Example 2 is significantly higher. Thus, it can be understood that the contrast between FIG. 1 showing the state of the black roughening according to Example 1 and FIG. 3 showing the state of the roughening treatment according to Comparative Example 2 has a completely different surface shape. From this, it can be understood that even if only the value of the maximum height difference (Wmax) of the bending is low, the intended roughening treatment surface of the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application has not been obtained.

Therefore, with respect to the lightness L * of the L * a * b * colorimetric system of the roughened surface, examples and comparative examples are prepared. The values of the lightness L * of the examples in Table 1 all include color tones of "lightness L * of 30 or less" in all of Example 1, Example 2, and Example 3. On the other hand, the roughness screens of Comparative Example 1 and Comparative Example 2 have a brightness L * of more than 30. Therefore, it can be understood that the values of haze of Comparative Example 1 and Comparative Example 2 were large. On the other hand, the rough surface of Comparative Example 3 is darker than the black rough surface of Example 3, and it is understood that some of the conventional copper foils have a color tone of "brightness L * of 30 or less" as in Comparative Example 3. Can be. However, at this time, the turbidity value (Haze) of Example 3 was 8, whereas the turbidity value (Haze) of Comparative Example 3 was very high (50) and lacked transparency. Therefore, even if only the value of the lightness L * of the L * a * b * colorimetric system shows good black, there may be cases where a black roughened surface suitable for the blackened surface-treated copper foil for flexible printed wiring board manufacturing according to the present application may not be obtained. Can understand.

In addition, from the contrast of FIGS. 1 and 2 to 4, when the adhesion state of the copper particles is observed, it can be understood that the copper particles of the examples are fine and many copper particles are uniformly attached, compared to the comparative example. As can be understood from Table 1, in Examples and Comparative Examples 1 and 2, the number of adhesion of the copper particles was clearly different. From this, compared to Comparative Example 1 and Comparative Example 2, the black roughened surface of the example has a fine black particle, and thus has a good black color tone, and has a flat surface free from bends and irregularities. Can understand. On the other hand, the number of adhesion of the copper particles in Comparative Example 3 is 471, and the condition that 400 to 2500 copper particles preferred for the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application is attached is satisfied. . However, as described above, the value of haze in Comparative Example 3 is very high, which is 50, and the transparency is lacking. Therefore, it can be understood that even if the number of copper particles simply attached is appropriate, a black roughened surface equivalent to the blackened surface-treated copper foil for manufacturing the flexible printed wiring board according to the present application has not been obtained.

As can be understood from the above, the black roughened screen provided with the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application has at least a condition that "the maximum height difference (Wmax) of bending is 1.2 µm or less". , It is necessary to have the condition that "the brightness of the L * a * b * colorimeter has a hue of 30 or less", and if this condition is satisfied, the CCD visibility of the flexible printed wiring board and the inspection accuracy of AOI are remarkable. I can understand that it is improved. In addition, the black roughened surface provided by the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application has conditions that 400 to 2500 copper particles are adhered to. It can be said that it is useful for improving the value of “Haze”.

In addition, when paying attention to the values of the dynamic friction coefficients of Examples and Comparative Examples, it is understood that there is no significant difference between the Examples and Comparative Examples, and the dynamic friction coefficient is 0.50 or more. From this, the black roughened surface of the blackened surface-treated copper foil according to the present application is laminated with a resin film and a blackened surface-treated copper foil by a roll lamination method, even if it has fine irregularities compared to the conventional surface-treated copper foil. When it does, slipping does not generate | occur | produce in the adhesive interface of a blackening surface-treated copper foil and a resin film. Further, no wrinkles or bubbles are generated at the adhesive interface, and it can be judged that good lamination can be performed.

As apparent from the preparation of the manufacturing conditions of the above-mentioned Examples and Comparative Examples, the blackened surface-treated copper foil according to the present application uses copper foil having a maximum height difference (Wmax) of bending of 1.2 µm or less on its surface. , It can be understood that it is possible to produce efficiently by performing black roughening using a copper electrolytic solution for black roughening containing 9-phenylacridine.

The blackened surface treatment copper foil which concerns on this application is a surface treatment copper foil suitable for manufacture of a flexible printed wiring board. This blackened surface-treated copper foil has a blackened surface that can improve CCD visibility and AOI detection accuracy, so that the alignment of the connection terminals of the liquid crystal display module and the connection terminals of the flexible printed wiring board is easy, and also formed. The inspection accuracy of the circuit is improved, and leakage of defective products can be effectively prevented. Further, the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application has fine black roughened particles formed of copper, and thus has good etching properties, and reduces the time of over-etching in etching during circuit formation. It is preferable because it can be shortened, and it is easy to reduce the running cost.

Claims (8)

In the surface-treated copper foil provided with a roughened surface for laminating on a resin film,
The roughened surface is a roughened surface with roughened particles having a particle diameter of 10 nm to 250 nm, the maximum height difference (Wmax) of curvature being 1.2 µm or less, and the brightness L of the L * a * b * colorimetric system. A blackened surface-treated copper foil for manufacturing flexible printed wiring boards, characterized in that * is a black roughened surface having a color tone of 30 or less. The blackened surface-treated copper foil according to claim 1, wherein the roughened particles are copper particles. The blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to claim 2, wherein 400 to 2500 copper particles are attached to the black rough surface in a region of 3 µm × 3 µm. The blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to any one of claims 1 to 3, wherein the black roughened surface has an average roughness Ra of 0.5 µm or less. It is the manufacturing method of the blackened surface-treated copper foil for manufacture of the flexible printed wiring board in any one of Claims 1-3,
On the surface where the maximum height difference (Wmax) of the bending of the copper foil is 1.2 µm or less, the concentration of copper is 10 g / L to 20 g / L, the concentration of free sulfuric acid is 15 g / L to 100 g / L, and the concentration of 9-phenylacridine is 100 mg. For the production of flexible printed wiring boards, characterized in that fine copper particles are attached and black roughened using a copper electrolytic solution for black roughening having a concentration of / L to 200 mg / L and a chlorine concentration of 20 mg / L to 100 mg / L. A method for producing a blackened surface-treated copper foil. The copper foil for black roughening at a solution temperature of 20 ° C to 40 ° C according to claim 5, wherein the copper foil is polarized with a negative electrode and electrolytically applied at a current density of 30A / dm ^{2 to} 100A / dm ² to the copper foil surface. A method for producing a blackened surface-treated copper foil for producing a flexible printed wiring board, wherein the adhesion formation of copper particles is performed. The copper clad laminated board obtained by using the blackened surface-treated copper foil for manufacture of the flexible printed wiring board in any one of Claims 1-3. A flexible printed wiring board, which is obtained by using the copper clad laminate according to claim 7.

Images