WO2014133164A1

WO2014133164A1 - Blackened surface-treated copper foil, method for manufacturing blackened surface-treated copper foil, copper-clad laminate and flexible printed circuit board

Info

Publication number: WO2014133164A1
Application number: PCT/JP2014/055173
Authority: WO
Inventors: 美智溝口; 小畠　真一; 歩立岡; 慎哉平岡; 隆司橋口
Original assignee: 三井金属鉱業株式会社
Priority date: 2013-02-28
Filing date: 2014-02-28
Publication date: 2014-09-04
Also published as: KR102116928B1; JP5705381B2; CN105008593A; TWI690625B; CN105008593B; KR20150090265A; KR20160135369A; MY181562A; JPWO2014133164A1; TW201447051A

Abstract

The purpose of the present invention is to provide a copper foil for a printed circuit board, the copper foil having: a blackened surface capable of improving CCD visibility during terminal connection processing and precision of flexible printed circuit board AOI detection; an appropriate roughness suitable for manufacturing flexible printed circuit boards; and favorable etching properties. To achieve said purpose, a blackened surface-treated copper foil, etc. for manufacturing flexible printed circuit boards is used, the foil being characterized in that the roughened surface of the surface-treated copper foil with a roughened surface is a black roughened surface for which the maximum high-low difference of the undulations (Wmax) is 1.2 µm or less and which is provided with a color tone having a L*a*b* color system lightness (L*) of 30 or less.

Description

Blackened surface-treated copper foil, method for producing blackened surface-treated copper foil, copper-clad laminate and flexible printed wiring 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 and a flexible printed wiring board obtained using the blackened surface-treated copper foil. It is related with the surface-treated copper foil which performed the fine roughening process which blackens on the surface of copper foil especially.

Conventionally, AOI (Automatic Optical Inspector) has been widely used for automatic inspection as an automatic visual inspection machine for printed wiring boards. AOI emits light from the back of the printed wiring board, captures the light transmitted through the printed wiring board, and reads the circuit pattern, thereby deviating from the specification, pattern chipping, pattern thinning, pinholes, scratches, It is a device that detects circuit defects such as shorts, pattern thickening, copper residue, protrusions, and dirt.

In recent years, when the liquid crystal display module and the flexible printed wiring board are connected by an anisotropic conductive film (ACF), the connection terminal of the liquid crystal display module and the connecting terminal of the flexible printed wiring board are connected to the flexible printed wiring board. Positioning is performed from the back of the circuit using a CCD camera. Therefore, it is desirable that a clear contrast exists as a color tone between the circuit back surface and the resin film. Therefore, generally, it is required that the adhesive surface of the copper foil used for circuit formation with the resin film is a good black color. On the other hand, good visibility is required for the resin film exposed by etching away 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 away the copper foil of the flexible printed wiring board.

Therefore, in the above-mentioned application, in order to improve the CCD visibility of the flexible printed wiring board and the AOI inspection accuracy, “the resin film exposed by etching away the copper foil of the flexible printed wiring board is excellent in light transmittance. The characteristics such as “the difference between the color tone of the circuit back surface and the color tone of the resin film is clear” are required. That is, the former requires the property that the resin film exposed by etching away the copper foil of the copper clad laminate has a low haze value, and the adhesive surface of the copper foil is on the resin film surface. This characteristic depends on the uneven shape to be left. And the latter is a characteristic influenced by the color tone with which the adhesion surface with the resin film of copper foil is provided. Examples of the copper foil satisfying these required characteristics include surface-treated copper foils disclosed in Patent Document 1 and Patent Document 2 below.

Patent Document 1 discloses a copper foil used for forming a copper layer of a flexible copper-clad laminate, and is intended to provide a surface-treated copper foil capable of forming a fine pitch circuit and having good adhesive strength after heating. "In the copper foil for forming the copper layer on the surface of the polyimide resin layer, the copper foil is a state in which the cobalt layer or the cobalt layer and the nickel-zinc alloy layer are laminated on the adhesive surface with the polyimide resin layer." A surface-treated copper foil for producing a flexible copper-clad laminate, which is characterized by comprising any one of the surface-treated layers, is disclosed, and is intended for a non-roughened surface-treated copper foil. In paragraph 0034 of the specification of Patent Document 1, “Furthermore, it is preferable that the surface of the surface-treated copper foil to be bonded to the polyimide resin substrate has a gloss [Gs (60 °)] of 70 or more. This is to ensure good fine-pitch circuit forming ability and good optical transparency required for optical automatic inspection (AOI inspection), for example ... (omitted) ... In the present invention, gloss The degree [Gs (60 °)] is 70 or more. However, when the gloss is less than 70, good fine pitch circuit forming ability cannot be obtained, and it is obtained at the time of inspection by an optical automatic inspection apparatus (AOI apparatus). It is difficult to ensure good light transmission. "

It is also conceivable to use a copper foil used for forming a black mask of a plasma display panel disclosed in Patent Document 2. This is because the copper foil for such use uses a copper foil with a color tone as close to black as possible. This Patent Document 2 discloses a copper foil used for manufacturing a conductive mesh used for shielding electromagnetic waves of a plasma display panel, and the surface of the blackened surface-treated copper foil disclosed in Patent Document 2 is formed by black mask formation. It is a nickel-based blackening surface or a cobalt-based blackening surface that meets the requirements. When a flexible printed wiring board is manufactured using the copper foil disclosed in Patent Document 2, the haze (Haze) of the resin film exposed by removing the copper foil of the flexible printed wiring board is low, and the light transmittance is excellent. It is considered that the difference in color tone required in the AOI of the flexible printed wiring board can be sufficiently satisfied.

JP 2008-132757 A W02007 / 007870 Publication

However, since the surface-treated copper foil for manufacturing a flexible copper-clad laminate disclosed in Patent Document 1 is a non-roughened surface-treated copper foil, it has flatness that does not roughen the surface of the resin film of the flexible printed wiring board. However, when the bonding surface of the surface-treated copper foil is excessively flat, wrinkles and bubbles are likely to occur at the bonding interface when the surface-treated copper foil and the resin film are bonded. Therefore, the surface-treated copper foil used for the flexible copper-clad laminate is required to have an appropriate roughness that is unlikely to cause wrinkles and bubbles and a flat adhesive surface.

Further, even when the blackened surface of the blackened surface-treated copper foil disclosed in Patent Document 2 is used for the production of a flexible copper-clad laminate, the surface-treated copper foil and the resin film are bonded together in the same manner as described above. Wrinkles and bubbles are likely to occur at the bonding interface. Furthermore, the blackened surface of the blackened surface-treated copper foil disclosed in Patent Document 2 is a nickel-based blackened surface or a cobalt-based blackened surface, and etching with a copper etchant tends to be difficult. Accordingly, when the circuit is formed, the time for overetching with the copper etching solution becomes long, so that the copper portion is excessively etched, and it becomes difficult to form a fine pitch circuit having an excellent etching factor. Even if a sufficient over-etching time is provided, nickel or cobalt remains between the circuits, the probability of migration increases, and the reliability of the product decreases, which is not preferable.

For these reasons, the present application has a blackened surface capable of improving CCD visibility and AOI detection accuracy equivalent to the copper foil disclosed in Patent Document 2, and is suitable for flexible printed wiring board production. Another object of the present invention is to provide a copper foil for a printed wiring board having an appropriate roughness and good etching characteristics.

Therefore, the inventors of the present invention have conceived to solve the above-described problems by using the following blackened surface-treated copper foil for manufacturing a flexible printed wiring board.

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 having a black roughened surface, and the black roughened surface has a maximum difference in waviness. (Wmax) is 1.2 μm or less, and the lightness L ^{* of} the L ^* a ^* b ^* color system has a color tone 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 attaching copper particles having a particle size of 10 nm to 250 nm.

It is preferable that 400 to 2500 copper particles adhere to the roughened black surface of the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application in an area 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 black roughened surface of the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application has a dynamic friction coefficient of 0.50 or more.

Method for producing blackened surface-treated copper foil: The method for producing a blackened surface-treated copper foil for producing a flexible printed wiring board according to the present application is the production of a blackened surface-treated copper foil for producing a flexible printed wiring board as described above. A copper foil has a maximum waviness difference (Wmax) of 1.2 μm or less, a copper concentration of 10 g / L to 20 g / L, a free sulfuric acid concentration of 15 g / L to 100 g / L, and 9-phenylacridine. A black roughening is performed by attaching fine copper particles using a black roughening copper electrolytic solution having a concentration of 100 mg / L to 200 mg / L and a chlorine concentration of 20 mg / L to 100 mg / L.

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

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

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

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. Further, the blackened surface-treated copper foil for producing a flexible printed wiring board according to the present application has good etching characteristics because fine roughened particles are formed of copper. Therefore, it is possible to shorten the over-etching time in etching at the time of circuit formation, and it is possible to form a fine pitch circuit having a very good etching factor.

It is a scanning electron microscope observation image which observed the roughening form of the blackening surface treatment copper foil for flexible printed wiring board manufacture which concerns on this application (Example 1). It is a scanning electron microscope observation image which observed the roughening process surface of the conventional surface treatment copper foil (comparative example 1). It is a scanning electron microscope observation image which observed the roughening process surface of the conventional surface treatment copper foil (comparative example 2). It is a scanning electron microscope observation image which observed the roughening process surface of the conventional surface treatment copper foil (comparative example 3).

Hereinafter, each form of “blackened surface-treated copper foil”, “manufacturing method of blackened surface-treated copper foil”, “copper-clad laminate”, and “flexible printed wiring board” according to the present application will be described.

Blackened surface-treated copper foil: The blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application has a maximum waviness difference (Wmax) of 1.2 μm or less, and L ^* a ^* b ^*. It is characterized by having a black roughened surface having a color tone having a lightness L ^* of 30 or less.

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 the waviness is 1.2 μm or less. This “maximum undulation height difference (Wmax)” refers to the difference in height in the waveform data extracted by filtering the waveform data relating to undulation from the information on the unevenness of the sample surface obtained using a three-dimensional surface structure analysis microscope. The maximum value (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 roughened surface with a maximum height difference (Wmax) of this undulation exceeding 1.2 μm, the copper foil of the flexible printed wiring board is removed by etching. The haze (Haze) of the resin film is increased, and the CCD visibility and AOI inspection accuracy are reduced. And in order to make this haze degree (Haze) into a low value stably, it is more preferable that the maximum height difference (Wmax) of a wave | undulation shall be 1.0 micrometer or less.

And the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application has a color tone whose L ^* a ^* b ^* color system lightness L ^* is 30 or less as defined in JIS Z8729. It is also characterized by comprising. When the lightness L ^{* of the} L ^* a ^* b ^* color system exceeds 30, the particle size of the roughened particles increases, and the haze (Haze) of the resin film exposed by etching away the copper foil of the flexible printed wiring board is removed. ) Becomes higher. In addition, if the lightness L ^{* of} the L ^* a ^* b ^* color system exceeds 30, the contrast between the color tone of the back surface of the circuit formed using this blackened surface-treated copper foil and the color tone of the resin film decreases. CCD visibility decreases, and AOI inspection accuracy tends to decrease. When the lightness L ^{* of} the L ^* a ^* b ^* color system is 20 or less, the haze (Haze) of the resin film is stably reduced. If the lightness L ^{* of} the L ^* a ^* b ^* color system is 15 or less, the haze of the resin film (Haze) and the contrast between the color tone of the back of the circuit and the color tone of the resin film are clarified. Visibility is further improved.

It is preferable that the black roughened surface of the blackened surface-treated copper foil for producing a flexible printed wiring board according to the present application has copper particles having a particle diameter of 10 nm to 250 nm attached thereto. Here, the lower limit of the particle size of the copper particles is 10 nm. However, this does not mean that the coarse particles having a particle diameter of less than 10 nm are positively excluded, but if the coarse particles become too fine, the anchor effect on the resin film may be lowered. On the other hand, when the particle size of the roughened particles exceeds 250 nm, the haze of the resin film portion exposed by etching and removing the copper foil of the copper clad laminate produced using the surface-treated copper foil increases. In addition, CCD visibility and AOI inspection accuracy are also lowered, which is not preferable. In addition, although there is no special limitation in the shape of a copper particle, it is preferable that a copper particle is a substantially spherical shape. This is because if the copper particles are substantially spherical, powder falling can be prevented.

In addition, it is preferable that 400 to 2500 copper particles adhere to the roughened black surface of the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application in an area of 3 μm × 3 μm. If the number of adhered copper particles in this predetermined region is less than 400, it is not preferable because the lightness L ^* of the above-mentioned L ^* a ^* b ^* color system is difficult to be 30 or less. On the other hand, when the number of adhered copper particles in a predetermined region exceeds 2500, the attached copper particles are likely to fall off, and the haze value tends to increase. This is not preferable because CCD visibility and AOI inspection accuracy are lowered.

The copper particles constituting the black roughened surface of the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application described above are composed of copper and inevitable impurities, and include alloy components that inhibit etching. It is preferably not included. If the copper particles have the same composition as the copper component constituting the copper foil, the etching rate in the copper etching solution is the same for the copper foil and the copper particles, so that the process design of circuit formation conditions by etching becomes easy. .

And as for the black roughening surface of the blackening surface treatment copper foil for flexible printed wiring board manufacture which concerns on this application, average roughness Ra when measured using a stylus type surface roughness meter is 0.5 micrometer or less. Preferably there is. The blackened surface-treated copper foil according to the present application has an extremely low value with respect to the average roughness. If this average roughness Ra exceeds 0.5 μm, in the etching process for forming the circuit, the overetching time provided so that the roughened particles that have entered the resin film between the wirings do not remain as etching residues will become long. This is not preferable because the side wall is dissolved more than necessary, and it becomes difficult to form a fine pitch circuit having a good etching factor. Further, the average roughness Ra is more preferably 0.3 μm or less. This is because it is possible to improve the chemical resistance performance by forming a fine pitch circuit with a good etching factor and at the same time preventing erosion of the solution to the laminated interface between the black roughened surface of the surface-treated copper foil and the resin film. .

Furthermore, 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 has a dynamic friction coefficient of 0.50 or more. When this dynamic friction coefficient is less than 0.50, the black roughened surface of the blackened surface-treated copper foil is too smooth when the resin film and the blackened surface-treated copper foil are laminated by the roll laminating method. Sliding occurs at the adhesive interface between the surface-treated copper foil and the resin film, and wrinkles are likely to occur, making it difficult to achieve good lamination. Moreover, when this dynamic friction coefficient is less than 0.50, there also exists a tendency for air bubbles to be easily generated at the adhesion interface between the blackened surface-treated copper foil and the resin film.

In addition, the blackened surface-treated copper foil described above is not particularly limited with respect to the thickness. In addition, it is clearly stated that the concept includes not only the surface of the normal copper foil subjected to black roughening but also the surface of the copper foil with carrier foil subjected to black roughening.

Method for producing blackened surface-treated copper foil: The method for producing a blackened surface-treated copper foil for producing a flexible printed wiring board according to the present application is the production of a blackened surface-treated copper foil for producing a flexible printed wiring board as described above. Then, black roughening is performed by attaching fine copper particles to the surface where the maximum height difference (Wmax) of the undulation of the copper foil is 1.2 μm or less. When the maximum height difference (Wmax) of the waviness of the adhesive surface with respect to the resin film exceeds 1.2 μm, the maximum height difference (Wmax) of the waviness is less likely to be 1.2 μm or less after black roughening. In consideration of variations in the process in the method for producing the blackened surface-treated copper foil, the maximum height difference (Wmax) of the waviness after the roughening of black is stably reduced to 1.2 μm or less. The maximum height difference (Wmax) is more preferably 0.8 μm or less.

Both the electrolytic copper foil and the rolled copper foil can be used as the copper foil before black roughening used in the method for producing the blackened surface-treated copper foil described above. Moreover, even if it is a copper foil in which the maximum height difference (Wmax) of the undulation exceeds 1.2 μm, the maximum undulation of the undulation can be obtained by performing etching treatment, copper plating treatment, etc. on such a copper foil surface. The difference (Wmax) may be 1.2 μm or less. And as long as the copper foil as used herein satisfies the condition that the maximum height difference (Wmax) of the swell of the adhesive surface to the resin film satisfies 1.2 μm or less, even if it is a non-roughened copper foil, preliminary roughening It may be given. Moreover, there is no special limitation regarding the thickness of copper foil.

When carrying out black roughening by attaching fine copper particles to a surface having a maximum height difference (Wmax) of the undulation of the copper foil of 1.2 μm or less, it is preferable to use the following black roughening copper electrolytic solution. 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 to 100 mg / L. A black roughening copper electrolytic solution is used. This black roughening copper electrolytic solution 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, and the industrially required productivity is not satisfied, which is not preferable. On the other hand, if the copper concentration exceeds 20 g / L, it is not preferable because it approaches smooth plating conditions and makes it difficult to roughen the black in relation to the current density described later. If the concentration of free sulfuric acid deviates from this concentration range due to the relationship with the copper concentration, the current-carrying characteristics during electrolysis change and it becomes difficult to achieve good black roughening.

In the case of the black roughening copper electrolytic solution used in the method for producing a blackened surface-treated copper foil for producing a flexible printed wiring board according to the present application, the 9-phenylacridine concentration is in the range of 100 mg / L to 200 mg / L. It is preferable to contain. This 9-phenylacridine functions as an additive that refines the particle size of copper particles adhering to the surface of the copper foil and promotes spheroidization of the particle shape. If the 9-phenylacridine concentration in the black roughening copper electrolytic solution is less than 100 mg / L, it is difficult to obtain the effect of reducing the particle size of the copper particles, and the effect of promoting the spheroidization of the particle shape is also reduced. It is not preferable. On the other hand, even when the concentration of 9-phenylacridine in the black roughening copper electrolytic solution exceeds 200 mg / L, the effect of refining the particle size of the copper particles and the effect of promoting the spheroidization of the particle shape are saturated simultaneously. Therefore, an effect proportional to the added amount cannot be obtained, and this is not preferable because it is simply a waste of resources.

Further, the chlorine concentration of the black roughening copper electrolytic solution used in the method for producing a blackened surface-treated copper foil for producing a flexible printed wiring board according to the present application may be contained in the range of 20 mg / L to 100 mg / L. preferable. When the chlorine concentration of the black roughening copper electrolytic solution is less than 20 mg / L, it is difficult to obtain a burned plating state for forming copper particles, and rough particles having a good shape cannot be obtained. It is not preferable. On the other hand, when the chlorine concentration of the black roughening copper electrolytic solution exceeds 100 mg / L, the color tone of the black roughened surface of the blackened surface-treated copper foil is likely to vary, and at the same time, the particle shape is spheroidized. This is not preferable because it is not performed well.

When performing black roughening on the surface of the copper foil using the black roughening copper electrolytic solution described above, the copper foil is polarized to the cathode in the copper electrolyte at a solution temperature of 20 ° C. to 40 ° C., and the current density Electrolysis is preferably performed at 30 A / dm ² to 100 A / 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., the shape of the coarse particles to be formed tends to vary, which is not preferable. On the other hand, when the solution temperature exceeds 40 ° C., the solution property of the black roughening copper electrolytic solution is likely to change, and there is a tendency that stable burn-out plating cannot be performed.

In the copper electrolyte, the current density when performing black roughening by polarizing the copper foil to the cathode is preferably in the range of 30 A / dm ² to 100 A / dm ² . When the current density is less than 30 A / dm ² , it is not preferable because sufficient black roughening cannot be performed and it becomes difficult to set the lightness L ^* of the black roughened surface to 30 or less. On the other hand, when the current density exceeds 100 A / dm ² , the precipitation rate of fine copper particles becomes excessive, and the shape of the formed copper particles does not become a good spherical body, which is not preferable.

Copper-clad laminate: A copper-clad laminate according to the present application is obtained by laminating the above-described blackened surface-treated copper foil for manufacturing a flexible printed wiring board and a resin film. It is. A polyimide resin film, a PET film, an aramid resin film, or the like can be used as the resin film at this time, but there is no particular limitation as long as it can be used as a resin film for a flexible printed wiring board. Moreover, the manufacture of a flexible copper clad laminated board employ | adopts a normal lamination system, a continuous lamination system, a casting system, etc., and can form a resin layer on the surface of blackening surface treatment copper foil. As used herein, the casting method refers to the formation of a resin composition film that is converted to a polyimide resin by heating, such as polyamic acid, on the surface of the blackened surface-treated copper foil according to the present invention. In this method, a polyimide resin film layer is directly formed on the surface of the surface-treated copper foil.

Flexible printed wiring board: This flexible printed wiring board is 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 state of the above-described copper-clad laminate. The haze (Haze) of the resin film to be reduced can be greatly reduced. The haze value varies depending on the type of 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, extremely low haze (when using the conventional surface-treated copper foil) ( Haze) can be obtained, and the CCD visibility and compatibility with AOI are remarkably increased.

In Example 1, an electrolytic copper foil having a thickness of 12 μm was produced, and blackened surface-treated copper foil was produced by performing blackening, rust prevention treatment, and silane coupling agent treatment. Contrast was performed.

Production of electrolytic copper foil: An acidic copper sulfate solution having the following composition was used as the copper electrolyte, a titanium rotating electrode with a surface roughness Ra = 0.20 μm was used as the cathode, and DSA was used as the 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 undulation of the deposited surface of this electrolytic copper foil was 0.8 μm.

Copper concentration: 80 g / L
Free sulfuric acid concentration: 140 g / L
Bis (3-sulfopropyl) disulfide concentration: 30 mg / L
Diallyldimethylammonium chloride polymer concentration: 50 mg / L
Chlorine concentration: 40mg / L

Black roughening: A black roughening copper electrolytic solution having the following composition is used for the deposition surface side of the electrode surface and the deposition surface included in the above-described electrolytic copper foil, a solution temperature of 30 ° C., and a current density of 50 A / Electrolysis was performed under the condition of dm ² to perform black roughening.

Copper concentration: 13g / L
Free sulfuric acid concentration: 55 g / L
9-phenylacridine concentration: 140 mg / L
Chlorine concentration: 35mg / L

Rust prevention treatment: When the black roughening described above was completed, a rust prevention treatment was performed on both surfaces of the electrolytic copper foil after the black roughening. Here, inorganic rust prevention under the conditions described below was adopted. Using a pyrophosphoric acid bath, zinc-nickel alloy rust-proofing treatment is performed at a potassium pyrophosphate concentration of 80 g / L, a zinc concentration of 0.2 g / L, a nickel concentration of 2 g / L, a liquid temperature of 40 ° C., and a current density of 0.5 A / dm ^2. went.

As a rust prevention treatment, a chromate layer was further formed on the zinc-nickel alloy rust prevention treatment. The chromate treatment was performed at a chromate 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 was completed, the silane coupling agent treatment was performed immediately after washing with water, and the silane coupling agent was adsorbed onto the rust prevention treatment layer on the black roughened surface. The solution used here was pure water as a solvent and a 3-aminopropyltrimethoxysilane concentration of 3 g / L. Then, this solution was sprayed onto the black roughened surface by showering to be adsorbed. When the adsorption of the silane coupling agent was completed, water was finally diffused by an electric heater to obtain a blackened surface-treated copper foil having a thickness of 12 μm.

FIG. 1 shows a scanning electron microscope observation image of the blackened surface-treated copper foil according to the present application obtained as described above. The evaluated characteristics are shown in Table 1 so as to facilitate comparison with the comparative example.

In Example 2, an electrolytic copper foil having a thickness of 12 μm was manufactured, and the blackened surface-treated copper foil was produced by performing the same black roughening, rust prevention treatment, and silane coupling agent treatment as in Example 1. .

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

The blackened surface-treated copper foil of Example 2 was obtained by performing the same black roughening, rust prevention treatment, and silane coupling agent treatment as in Example 1 using the above-described electrolytic copper foil. The evaluated characteristics are shown in Table 1 so as to facilitate comparison with the comparative example.

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

Black roughening: Preliminary roughening treatment was performed on the deposition surface side of the electrode surface and the deposition surface included in the above-described electrolytic copper foil. The preliminary roughening treatment at this time was performed by the following two-stage process.

The first stage of the preliminary roughening treatment uses a copper electrolytic solution for roughening treatment with a copper concentration of 18 g / l and a free sulfuric acid concentration of 70 g / l, at a solution temperature of 25 ° C. and a current density of 4 A / dm ² . Electrolysis was performed for 4 seconds and washed with water. In the second stage, using a copper electrolytic solution having a copper concentration of 65 g / l and a free sulfuric acid concentration of 60 g / l, electrolysis is performed at a solution temperature of 45 ° C. and a current density of 5 A / dm ² for 5 seconds, and washed with water. A preliminary roughening treatment was performed. The precipitation surface of the electrolytic copper foil at this stage had a maximum waviness difference (Wmax) of 0.9 μm. Therefore, it can be understood that the precipitation surface before the preliminary roughening treatment has a maximum waviness difference (Wmax) of 0.8 μm, and the waviness does not fluctuate greatly and is in an appropriate range.

And the blackened surface-treated copper foil of Example 3 was performed to the said precipitation surface which performed the preliminary roughening process like Example 1 by carrying out black roughening, an antirust process, and a silane coupling agent process. Got. The evaluated characteristics are shown in Table 1 so as to facilitate comparison with the comparative example.

Comparative example

[Comparative Example 1]
In Comparative Example 1, the surface of the electrolytic copper foil used in Example 1 was roughened by a method different from Example 1. Therefore, since only the roughening process is different from the first embodiment, only the roughening process will be described in detail below.

Roughening treatment: In Comparative Example 1, the precipitation surface of the electrolytic copper foil was subjected to a roughening treatment by the following two-stage process. The first stage of the roughening treatment uses a copper electrolytic solution 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. The solution was electrolyzed at a solution temperature of 30 ° C. and a current density of 19 A / dm ² and washed with water. The second stage uses a copper electrolytic solution having a copper concentration of 65 g / l and a free sulfuric acid concentration of 90 g / l, electrolyzing at a solution temperature of 48 ° C. and a current density of 15 A / dm ² , washing with water, and roughening treatment. Went.

When the above-described roughening treatment was completed, the same rust prevention treatment and silane coupling agent treatment as in Example 1 were performed, and the surface-treated copper foil of Comparative Example 1 was obtained. A scanning electron microscope observation image of the surface-treated copper foil of Comparative Example 1 is shown in FIG. The evaluated characteristics are shown in Table 1 so as to facilitate comparison with the examples.

[Comparative Example 2]
In Comparative Example 2, the same electrolytic copper foil as in Example 1 was used, and the same precipitation surface as in Example 1 was subjected to a roughening treatment by a method different from that in Example 1. Therefore, since only the roughening process is different from the first embodiment, only the roughening process will be described in detail below.

Roughening treatment: In Comparative Example 2, a roughening treatment was performed on the deposited surface of the electrolytic copper foil by the following method. The first stage of the roughening treatment uses 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, a solution temperature of 25 ° C., a current density of 10 A / dm ² , an energization time of 10 Electrolyzed in seconds and washed with water. In the second stage, using a copper electrolytic solution having a copper concentration of 65 g / l and a free sulfuric acid concentration of 60 g / l, electrolysis is carried out for 20 seconds at a liquid temperature of 45 ° C. and a current density of 15 A / dm ² for roughening. Processed.

When the above-mentioned roughening treatment was completed, the same rust prevention treatment and silane coupling agent treatment as in Example were performed, and the surface-treated copper foil of Comparative Example 2 was obtained. A scanning electron microscope observation image of the surface-treated copper foil of Comparative Example 2 is shown in FIG. The evaluated characteristics are shown in Table 1 so as to facilitate comparison with the examples.

[Comparative Example 3]
In Comparative Example 3, the same electrolytic copper foil as in Example 1 was used, and the same roughening treatment, rust prevention treatment, and silane coupling as in Example 1 were applied to the electrode surface opposite to the deposition surface used in Example 1. Agent treatment was performed. Therefore, since only the surface subjected to the roughening process is different from that of the first embodiment, a detailed description thereof is omitted. A scanning electron microscope observation image of the surface-treated copper foil according to Comparative Example 3 is shown in FIG. The evaluated characteristics are shown in Table 1 so as to facilitate comparison with the examples.

[Evaluation methods]
Maximum height difference of waviness (Wmax): zygo New View 5032 (manufactured by Zygo) was used as a measuring instrument, and Metro Pro Ver. The maximum height difference (Wmax) of the waviness was measured by using the condition of 11 μm for the low frequency filter using 8.0.2. At this time, the surface to be measured of the surface-treated copper foil is fixed in close contact with the sample stage, and 6 fields of 108 μm × 144 μm are selected and measured within the 1 cm square range of the sample piece, and 6 measurements are made. The average value of the maximum height difference (Wmax) of the swell obtained from the points was adopted as a representative value.

Lightness L ^* : Measured according to JIS Z8729 using a model SE2000 manufactured by Nippon Denshoku Industries Co., Ltd.

Average roughness (Ra): Measured in accordance with JIS B0601 using a stylus type surface roughness meter manufactured by Kosaka Laboratory, SE3500 (stylus curvature radius: 2 μm).

Number of adhered copper particles: Field emission type scanning observed from 45 ° oblique direction with respect to the black roughened surface of the blackened surface-treated copper foil according to the example and the roughened surface of the surface-treated copper foil according to the comparative example. The number of adhered copper particles that can be observed in an area of 3 μm × 3 μm in a scanning electron microscope observation image (magnification: 20000 times) was visually counted.

Coefficient of dynamic friction: Measured using a tripogear surface property measuring machine TYPE 14 manufactured by Shinto Kagaku Co., Ltd. A polyimide resin film with a thickness of 50 μm (Upilex manufactured by Ube Industries Co., Ltd.) is fixed to the measurement stage, and the surface-treated copper foil is frictioned so that the polyimide resin film and the roughened surface of the surface-treated copper foil face each other. Secure to. Then, the measurement time and frictional resistance force are output under the conditions of a vertical load of 100 g, a moving speed of 100 mm / min, and a moving distance of 10 mm. From the above, the dynamic friction coefficient was calculated.

Cloudiness (Haze): A surface-treated copper foil and a PET film were thermocompression bonded to produce a copper-clad laminate. Thereafter, the surface-treated copper foil was removed by etching, and the remaining PET film was removed from the film at 23 ° C. according to JIS-K7136 (2000) using a haze meter NDH5000 (manufactured by Nippon Denshoku Industries Co., Ltd.). The haze (Haze: unit%) was measured at three locations, and the average value was determined.

[Contrast between Example and Comparative Example]
First, referring to the drawings, the “maximum difference in waviness (Wmax)” of the example and the comparative example will be compared. The value of the maximum height difference (Wmax) of the waviness of the comparative examples is higher than the maximum height difference (Wmax) of the waviness of the examples, and the haze value (Haze) of these comparative examples is also higher than the examples. It can be understood that transparency is lacking.

However, it seems that the maximum difference in waviness (Wmax) of the waviness in Comparative Example 2 is not significantly different from the maximum difference in waviness (Wmax) of the waviness in Example 2. However, looking at the value of 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 remarkably high. . Thus, when FIG. 1 showing the black roughening state according to Example 1 is compared with FIG. 3 showing the roughening state according to Comparative Example 2, it can be understood that the surface shape is completely different. From this, even if only the value of the maximum height difference (Wmax) of the swell is low, the intended roughened surface of the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application is not obtained. Understandable.

Therefore, the working example and the comparative example will be compared with respect to L ^* a ^* b ^* color system lightness L ^{* of} the roughened surface. The values of the lightness L ^* of the examples in Table 1 have the color tone of “lightness L ^* is 30 or less” in both the first, second, and third examples. On the other hand, the lightness L ^* of the roughened surfaces of Comparative Example 1 and Comparative Example 2 exceeds 30. Therefore, it can be understood that the haze value of Comparative Example 1 and Comparative Example 2 is large. On the other hand, the roughened surface of Comparative Example 3 has a darker color tone than the black roughened surface of Example 3, and in the conventional copper foil, “lightness L ^* is 30 or less” as in Comparative Example 3. It turns out that there is what has a color tone. However, at this time, the haze value of Example 3 is 8 while the haze value of Comparative Example 3 is as high as 50, which is lacking in transparency. Therefore, even if only the value of the lightness L ^* of the L ^* a ^* b ^* color system indicates a good black color, the black roughened surface preferable for the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application It can be understood that may not be obtained.

From the comparison between FIG. 1 and FIG. 2 to FIG. 4, the copper particles in the example are finer than the comparative example, and a large number of copper particles are uniformly attached. I can understand that. As can be understood from Table 1, the number of adhered copper particles is clearly different between the example and the comparative examples 1 and 2. From this, compared with the comparative example 1 and the comparative example 2, the black roughening surface in an Example has a favorable black color tone by many fine copper particles adhering, and is flat without a wave | undulation and unevenness | corrugation. It can be understood that it is a smooth surface. On the other hand, the number of adhered copper particles in Comparative Example 3 is 471, and the preferred 400 to 2500 copper particles of the blackened surface-treated copper foil for producing a flexible printed wiring board according to the present application are adhered. The condition is met. However, similarly to the above, the haze value of Comparative Example 3 is as high as 50 and lacks transparency. Therefore, it can be understood that a black roughened surface equivalent to the blackened surface-treated copper foil for producing a flexible printed wiring board according to the present application is not obtained even if the number of simply attached copper particles is appropriate.

As can be understood from the above, the black roughened surface provided in the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application has at least a “maximum undulation height difference (Wmax) of 1.2 μm or less. And the condition that “L ^* a ^* b ^* color system lightness L ^* has a color tone of 30 or less” must be included. It can be understood that the inspection accuracy of the property and AOI is remarkably improved. Further, the black roughened surface provided in the blackened surface-treated copper foil for producing a flexible printed wiring board according to the present application has a condition that 400 to 2500 copper particles are attached, It can be said that it is useful for improving the value of “Haze” in the present application.

Further, when attention is paid to the value of the dynamic friction coefficient between the example and the comparative example, it can be understood that there is no significant difference between the example and the comparative example, and the dynamic friction coefficient is 0.50 or more. From this, even if the black roughened surface of the blackened surface-treated copper foil according to the present application has fine irregularities compared to the conventional surface-treated copper foil, the resin film and the blackened surface are obtained by the roll laminating method. When the treated copper foil is laminated, no slip occurs at the adhesive interface between the blackened surface-treated copper foil and the resin film. Moreover, it can be judged that neither good wrinkles nor bubbles are generated at the bonding interface, and that good lamination can be achieved.

As is clear from the comparison of the manufacturing conditions of the above-described Examples and Comparative Examples, the blackened surface-treated copper foil according to the present application uses a copper foil having a maximum waviness difference (Wmax) of 1.2 μm or less. Thus, it can be understood that the surface can be efficiently produced by performing black roughening using a black roughening copper electrolytic solution containing 9-phenylacridine.

The blackened surface-treated copper foil according to the present application is a surface-treated copper foil suitable for manufacturing a flexible printed wiring board. Since this blackened surface-treated copper foil has a blackened surface that can improve CCD visibility and AOI detection accuracy, it is easy to align the connection terminals of the liquid crystal display module and the connection terminals of the flexible printed wiring board, In addition, the inspection accuracy of the formed circuit is improved and the outflow of defective products can be efficiently prevented. In addition, the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to the present application has good etching characteristics because fine black roughened particles are formed of copper, and over-etching during circuit formation. Etching time can be shortened, and the running cost can be easily reduced, which is preferable.

Claims

In the surface-treated copper foil provided with the roughened surface,
The roughened surface is a black roughened surface having a color tone having a maximum waviness difference (Wmax) of 1.2 μm or less and a lightness L * of the L * a * b * color system of 30 or less. A blackened surface-treated copper foil for producing a flexible printed wiring board, characterized in that:
The blackened surface-treated copper foil for producing a flexible printed wiring board according to claim 1, wherein the roughened black surface is roughened by attaching copper particles having a particle size of 10 nm to 250 nm.
The blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to claim 2, wherein 400 to 2500 copper particles adhere to the roughened black 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.
The blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to any one of claims 1 to 4, wherein the roughened black surface has a dynamic friction coefficient of 0.50 or more.
A method for producing a blackened surface-treated copper foil for producing a flexible printed wiring board according to any one of claims 1 to 5,
On the surface where the maximum height difference (Wmax) of the undulation of the copper foil 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. Flexible printed wiring board manufacturing, characterized in that fine copper particles are attached to black roughening using a black electrolytic copper solution for blackening, having a chlorine concentration of 20 mg / L to 100 mg / L. For producing a blackened surface-treated copper foil for use.
Copper particles on the surface of the copper foil are obtained by polarizing the copper foil to the cathode in a black roughening copper electrolytic solution having a solution temperature of 20 ° C. to 40 ° C. and performing electrolysis at a current density of 30 A / dm 2 to 100 A / dm 2. The method for producing a blackened surface-treated copper foil for producing a flexible printed wiring board according to claim 6.
A copper-clad laminate obtained by using the blackened surface-treated copper foil for manufacturing a flexible printed wiring board according to any one of claims 1 to 5.
A flexible printed wiring board obtained by using the copper-clad laminate according to claim 8.