JP2014141729A - Surface-treated copper foil and laminate sheet using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface-treated copper foil which adheres well to a resin and gives the resin excellent transparency after an etching removal of the copper foil and a laminate sheet using it.SOLUTION: The surface-treated copper foil has Sv of 3.5 or greater, and Sv is determined by laminating the treated surface of copper foil on both sides of a polyimide resin substrate, removing the copper foil on both sides by etching, laying a print printed with a line-shaped mark under the exposed polyimide substrate and photographing the mark through the polyimide substrate with a CCD camera, measuring brightness at each of observation points along the direction perpendicular to the line-shaped mark from obtained images to create an observation point-brightness curve graphic chart, determining the top average value Bt and the bottom average value Bb of the brightness curve and calculating Sv by the equation Sv=(ΔB×0.1)/(t1-t2), where t1 is the value representing the position of the intersection point closest to the line-shaped mark, among intersection points between the brightness curve and Bt; and t2 is the value representing the position of the intersection point closest to the line-shaped mark in the depth range from the intersection point corresponding to t1 to the depth of 0.1ΔB (ΔB=Bt-Bb) with respect to Bt.

Description

  The present invention relates to a surface-treated copper foil and a laminate using the surface-treated copper foil, and in particular, a surface-treated copper foil suitable for a field where transparency of the remaining resin after etching the copper foil is required, and a laminate using the same. Regarding the board.

  In a small electronic device such as a smartphone or a tablet PC, a flexible printed wiring board (hereinafter referred to as FPC) is adopted because of easy wiring and light weight. In recent years, with the enhancement of functions of these electronic devices, the signal transmission speed has been increased, and impedance matching has become an important factor in FPC. As a measure for impedance matching with respect to an increase in signal capacity, a resin insulation layer (for example, polyimide) serving as a base of an FPC has been increased in thickness. In addition, the demand for higher wiring density has further increased the number of FPC layers. On the other hand, processing such as bonding to a liquid crystal substrate and mounting of an IC chip is performed on the FPC, but the alignment at this time is the resin insulation remaining after etching the copper foil in the laminate of the copper foil and the resin insulating layer The visibility of the resin insulation layer is important because it is performed through a positioning pattern that is visible through the layer.

  Moreover, the copper clad laminated board which is a laminated board of copper foil and a resin insulating layer can also be manufactured even if it uses the rolled copper foil by which roughening plating was given to the surface. This rolled copper foil usually uses tough pitch copper (oxygen content of 100 to 500 ppm by weight) or oxygen-free copper (oxygen content of 10 ppm by weight or less) as a raw material, and after hot rolling these ingots, It is manufactured by repeating cold rolling and annealing to a thickness.

As such a technique, for example, in Patent Document 1, a polyimide film and a low-roughness copper foil are laminated, and a light transmittance at a wavelength of 600 nm of the film after copper foil etching is 40% or more, a haze value. An invention relating to a copper clad laminate having (HAZE) of 30% or less and an adhesive strength of 500 N / m or more is disclosed.
Further, Patent Document 2 has an insulating layer in which a conductive layer made of electrolytic copper foil is laminated, and the light transmittance of the insulating layer in the etching region when the circuit is formed by etching the conductive layer is 50% or more. In a flexible printed wiring board for chip-on-flex (COF), the electrolytic copper foil has a rust-proofing layer made of a nickel-zinc alloy on an adhesive surface bonded to an insulating layer, and the surface roughness (Rz) of the adhesive surface ) Is 0.05 to 1.5 μm, and the specular gloss at an incident angle of 60 ° is 250 or more, and an invention relating to a flexible printed wiring board for COF is disclosed.
Moreover, in patent document 3, in the processing method of the copper foil for printed circuits, after the roughening process by copper-cobalt-nickel alloy plating on the surface of copper foil, a cobalt-nickel alloy plating layer is formed, and also zinc-nickel An invention relating to a method for treating a copper foil for printed circuit, characterized by forming an alloy plating layer is disclosed.

JP 2004-98659 A WO2003 / 096776 Japanese Patent No. 2849059

In Patent Document 1, a low-roughness copper foil obtained by improving adhesion with an organic treatment agent after blackening treatment or plating treatment is broken due to fatigue in applications where flexibility is required for a copper-clad laminate. May be inferior in resin transparency.
Moreover, in patent document 2, the roughening process is not made and the adhesive strength of copper foil and resin is low and inadequate in uses other than the flexible printed wiring board for COF.
Furthermore, in the processing method described in Patent Document 3, Cu-Co-Ni fine processing on the copper foil was possible, but the resin after bonding the copper foil with the resin and removing it by etching was excellent. Transparency is not realized.
The present invention provides a surface-treated copper foil that adheres well to a resin and is excellent in the transparency of a resin after the copper foil is removed by etching, and a laminate using the same.

  As a result of intensive studies, the present inventors have obtained a copper foil in which the ratio C / A between the surface area A obtained when the surface is viewed in plan and the convex volume C on the surface is controlled within a predetermined range by surface treatment. An observation point-brightness obtained from an image of the mark portion obtained by placing the printed matter with the mark on the polyimide substrate removed from the processing surface side and pasting the polyimide substrate through the polyimide substrate. Paying attention to the slope of the brightness curve near the mark edge drawn in the graph, controlling the slope of the brightness curve is not affected by the type of substrate resin film or the thickness of the substrate resin film, It has been found that it affects the resin transparency after etching.

The present invention completed on the basis of the above knowledge is, in one aspect, surface treatment is performed on at least one surface, and a surface area A obtained when viewing the surface on which the surface treatment is performed, A surface-treated copper foil having a ratio C / A to the convex volume C of the surface of 2.11 to 23.91, wherein both surfaces of the polyimide resin substrate are formed from the surface side where the surface treatment is performed on the copper foil. Then, the copper foils on both sides are removed by etching, and a printed matter on which a line-shaped mark is printed is laid under the exposed polyimide substrate, and the printed matter is photographed with a CCD camera through the polyimide substrate. The observation point-brightness group is obtained by measuring the brightness at each observation point along the direction perpendicular to the direction in which the observed line-shaped mark extends for the image obtained by the photographing. The difference between the top average value Bt and the bottom average value Bb of the brightness curve generated from the end of the mark to the portion where the mark is not drawn is ΔB (ΔB = Bt−Bb), and the observation point-lightness graph , The value indicating the position of the intersection closest to the line-shaped mark among the intersections of the lightness curve and Bt is t1, and the depth range from the intersection of the lightness curve and Bt to 0.1 ΔB with reference to Bt , When the value indicating the position of the intersection closest to the line-shaped mark among the intersections of the lightness curve and 0.1 ΔB is t2, Sv defined by the following equation (1) is 3.5 or more It becomes.
Sv = (ΔB × 0.1) / (t1-t2) (1)

  In another embodiment of the surface-treated copper foil according to the present invention, the ratio C / A is 2.95 to 21.42.

  In still another embodiment of the surface-treated copper foil according to the present invention, Sv defined by the formula (1) in the brightness curve is 3.9 or more.

  In still another embodiment of the surface-treated copper foil according to the present invention, Sv defined by the formula (1) in the brightness curve is 5.0 or more.

  In still another embodiment of the surface-treated copper foil according to the present invention, the TD ten-point average roughness Rz of the surface is 0.20 to 0.64 μm.

  In still another embodiment of the surface-treated copper foil according to the present invention, the TD ten-point average roughness Rz of the surface is 0.40 to 0.62 μm.

  In still another embodiment of the surface-treated copper foil according to the present invention, the ratio B / A between the three-dimensional surface area B of the surface and the two-dimensional surface area (surface area obtained when the surface is viewed in plan) A is 1 0.0 to 1.7.

  In still another embodiment of the surface-treated copper foil according to the present invention, the B / A is 1.0 to 1.6.

  In still another aspect, the present invention is a laminated plate configured by laminating the surface-treated copper foil of the present invention and a resin substrate.

  In still another aspect, the present invention is a printed wiring board using the surface-treated copper foil of the present invention.

  In still another aspect, the present invention is an electronic device using the printed wiring board of the present invention.

  In still another aspect, the present invention is a method of manufacturing a printed wiring board in which two or more printed wiring boards are connected by connecting two or more printed wiring boards of the present invention.

  In yet another aspect, the present invention includes a step of connecting at least one printed wiring board of the present invention and another printed wiring board of the present invention or a printed wiring board not corresponding to the printed wiring board of the present invention, This is a method for manufacturing a printed wiring board in which two or more printed wiring boards are connected.

  In still another aspect, the present invention is an electronic apparatus using one or more printed wiring boards to which at least one printed wiring board of the present invention is connected.

  In still another aspect, the present invention is a method for manufacturing a printed wiring board, including at least a step of connecting the printed wiring board of the present invention and a component.

  In yet another aspect of the present invention, the step of connecting at least one printed wiring board of the present invention to another printed wiring board of the present invention or a printed wiring board not corresponding to the printed wiring board of the present invention, and A method of manufacturing a printed wiring board having two or more printed wiring boards connected, comprising at least a step of connecting a printed wiring board of the present invention or a printed wiring board having two or more printed wiring boards of the present invention connected thereto and a component. It is.

  ADVANTAGE OF THE INVENTION According to this invention, the surface-treated copper foil excellent in transparency of resin after adhere | attaching resin favorably and removing copper foil by an etching, and a laminated board using the same can be provided.

It is a schematic diagram which defines Bt and Bb. It is a schematic diagram which defines t1, t2, and Sv. It is a schematic diagram showing the structure of an imaging device and the measuring method of the inclination of a lightness curve in the case of evaluation of the lightness curve inclination. It is a SEM observation photograph of the copper foil surface of the comparative example 1 in the case of Rz evaluation. It is a SEM observation photograph of the copper foil surface of Example 1 in the case of Rz evaluation. It is a SEM observation photograph of the copper foil surface of Example 2 in the case of Rz evaluation. It is a SEM observation photograph of the copper foil surface of Example 3 in the case of Rz evaluation. It is a SEM observation photograph of the copper foil surface of Example 4 in the case of Rz evaluation. It is a SEM observation photograph on the copper foil surface of Example 5 in the case of Rz evaluation. It is a SEM observation photograph of the copper foil surface of Example 6 in the case of Rz evaluation. It is a SEM observation photograph of the copper foil surface of Example 7 in the case of Rz evaluation. It is a SEM observation photograph of the copper foil surface of Example 8 in the case of Rz evaluation. It is a SEM observation photograph of the copper foil surface of the comparative example 2 in the case of Rz evaluation. It is a SEM observation photograph of the copper foil surface of the comparative example 3 in the case of Rz evaluation.

[Form and manufacturing method of surface-treated copper foil]
The copper foil used in the present invention is useful for a copper foil used by making a laminate by bonding to a resin substrate and removing it by etching.
The copper foil used in the present invention may be either an electrolytic copper foil or a rolled copper foil. Usually, the surface of the copper foil that adheres to the resin substrate, that is, the surface on the surface treatment side, has the shape of the surface of the copper foil after degreasing for the purpose of improving the peel strength of the copper foil after lamination. A roughening treatment for performing electrodeposition may be performed. Although the electrolytic copper foil has irregularities at the time of manufacture, the irregularities can be further increased by enhancing the convex portions of the electrolytic copper foil by roughening treatment. In the present invention, this roughening treatment can be performed by copper-cobalt-nickel alloy plating, copper-nickel-phosphorus alloy plating, or the like. Ordinary copper plating or the like may be performed as a pretreatment before roughening, and ordinary copper plating or the like may be performed as a finishing treatment after roughening in order to prevent electrodeposits from dropping off. The content of treatment may be somewhat different between the rolled copper foil and the electrolytic copper foil. In the present invention, including such pretreatment and finishing treatment, known treatments related to copper foil roughening are included as necessary, and are collectively referred to as roughening treatment.
The copper foil used in the present invention may be subjected to a roughening treatment, or the roughening treatment may be omitted and a heat-resistant plating layer or a rust-proof plating layer may be applied to the surface. In this invention, you may include the well-known process relevant to such a heat-resistant plating layer and an antirust plating layer as needed.
The thickness of the copper foil used in the present invention is not particularly limited, but is, for example, 1 μm or more, 2 μm or more, 3 μm or more, 5 μm or more, for example, 3000 μm or less, 1500 μm or less, 800 μm or less, 300 μm or less, 150 μm or less. 100 μm or less, 70 μm or less, 50 μm or less, or 40 μm or less.
The rolled copper foil that can be used in the present invention contains one or more elements such as Ag, Sn, In, Ti, Zn, Zr, Fe, P, Ni, Si, Te, Cr, Nb, V, and B. Copper alloy foil is also included. When the concentration of the above elements increases (for example, 10% by mass or more in total), the conductivity may decrease. The conductivity of the rolled copper foil is preferably 50% IACS or more, more preferably 60% IACS or more, and still more preferably 80% IACS or more.

Moreover, an example of the manufacturing conditions of the electrolytic copper foil which can be used for this invention is shown below.
<Electrolyte composition>
Copper: 90-110 g / L
Sulfuric acid: 90-110 g / L
Chlorine: 50-100ppm
Leveling agent 1 (bis (3sulfopropyl) disulfide): 10 to 30 ppm
Leveling agent 2 (amine compound): 10 to 30 ppm
As the amine compound, an amine compound having the following chemical formula can be used.

(In the above chemical formula, R ₁ and R ₂ are selected from the group consisting of a hydroxyalkyl group, an ether group, an aryl group, an aromatic substituted alkyl group, an unsaturated hydrocarbon group, and an alkyl group.)

<Production conditions>
Current density: 70 to 100 A / dm ²
Electrolyte temperature: 50-60 ° C
Electrolyte linear velocity: 3-5 m / sec
Electrolysis time: 0.5 to 10 minutes

Copper as roughening treatment - cobalt - nickel alloy plating, by electrolytic plating, coating weight is to be the 15~40mg / dm ² of copper -100~3000μg / dm ² of cobalt -100~1500μg / dm ² of nickel It can be carried out so as to form a ternary alloy layer. If the amount of deposited Co is less than 100 μg / dm ² , the heat resistance may deteriorate and the etching property may deteriorate. When the amount of Co deposition exceeds 3000 μg / dm ² , it is not preferable when the influence of magnetism must be taken into account, etching spots may occur, and acid resistance and chemical resistance may deteriorate. If the Ni adhesion amount is less than 100 μg / dm ² , the heat resistance may deteriorate. On the other hand, when the Ni adhesion amount exceeds 1500 μg / dm ² , the etching residue may increase. A preferable Co adhesion amount is 1000 to 2500 μg / dm ² , and a preferable nickel adhesion amount is 500 to 1200 μg / dm ² . Here, the etching stain means that Co remains without being dissolved when etched with copper chloride, and the etching residue means that Ni remains without being dissolved when alkaline etching is performed with ammonium chloride. It means that.

An example of a general bath and plating conditions for forming such a ternary copper-cobalt-nickel alloy plating is as follows:
Plating bath composition: Cu 10-20 g / L, Co 1-10 g / L, Ni 1-10 g / L
pH: 1-4
Temperature: 30-50 ° C
Current density D _k : 20 to 30 A / dm ²
Plating time: 1-5 seconds

After the roughening treatment, a cobalt-nickel alloy plating layer of nickel having an adhesion amount of 200 to 3000 μg / dm ² and cobalt-100 to 700 μg / dm ² can be formed on the roughened surface. This treatment can be regarded as a kind of rust prevention treatment in a broad sense. This cobalt-nickel alloy plating layer needs to be performed to such an extent that the adhesive strength between the copper foil and the substrate is not substantially reduced. If the amount of cobalt adhesion is less than 200 μg / dm ² , the heat-resistant peel strength is lowered, and the oxidation resistance and chemical resistance may be deteriorated. As another reason, if the amount of cobalt is small, the treated surface becomes reddish, which is not preferable. When the amount of cobalt deposition exceeds 3000 μg / dm ² , it is not preferable when the influence of magnetism must be taken into account, and etching spots may occur, and acid resistance and chemical resistance may deteriorate. A preferable cobalt adhesion amount is 500 to 2500 μg / dm ² . On the other hand, if the nickel adhesion amount is less than 100 μg / dm ² , the heat-resistant peel strength is lowered, and the oxidation resistance and chemical resistance may be deteriorated. When nickel exceeds 1300 microgram / dm < ² >, alkali etching property will worsen. A preferable nickel adhesion amount is 200 to 1200 μg / dm ² .

An example of the conditions for cobalt-nickel alloy plating is as follows:
Plating bath composition: Co 1-20 g / L, Ni 1-20 g / L
pH: 1.5-3.5
Temperature: 30-80 ° C
Current density D _k : 1.0 to 20.0 A / dm ²
Plating time: 0.5-4 seconds

According to the present invention, a zinc plating layer having an adhesion amount of 30 to 250 μg / dm ² is further formed on the cobalt-nickel alloy plating. If the zinc adhesion amount is less than 30 μg / dm ² , the heat deterioration rate improving effect may be lost. On the other hand, when the zinc adhesion amount exceeds 250 μg / dm ² , the hydrochloric acid deterioration rate may be extremely deteriorated. Preferably, the zinc adhesion amount is 30 to 240 μg / dm ² , more preferably 80 to 220 μg / dm ² .

An example of the galvanizing conditions is as follows:
Plating bath composition: Zn 100 to 300 g / L
pH: 3-4
Temperature: 50-60 ° C
Current density D _k : 0.1 to 0.5 A / dm ²
Plating time: 1-3 seconds

  A zinc alloy plating layer such as zinc-nickel alloy plating may be formed instead of the zinc plating layer, and a rust prevention layer may be formed on the outermost surface by chromate treatment or application of a silane coupling agent. Good.

  In the surface-treated copper foil of the present invention, the ratio C / A of the surface area A and the convex volume C is controlled by adjusting the current density of the roughened particles and the plating time as described above. . When the plating process is performed at a high current density, small rough particles are obtained, and when the plating process is performed at a low current density, large rough particles are obtained. Since the number of particles formed under these conditions is determined by the plating time, the convex volume C is determined by a combination of the current density and the plating time.

[Ratio C / A of surface area A of copper foil surface and convex volume C]
In the surface-treated copper foil of the present invention, the ratio C / A between the surface area A obtained when the surface is viewed in plan and the convex volume C of the surface is 2.11 to 23.91 on at least one surface. Is controlled. With such a configuration, the peel strength is increased and the resin is satisfactorily bonded to the resin, and the transparency of the resin after the copper foil is removed by etching is increased. As a result, alignment and the like when mounting an IC chip through a positioning pattern that is visible through the resin are facilitated. When the ratio C / A is less than 2.11 μm, the roughening treatment on the surface of the copper foil becomes insufficient, causing a problem that the resin cannot be sufficiently bonded. On the other hand, if the ratio C / A is more than 23.91 μm, the unevenness of the resin surface after the copper foil is removed by etching increases, resulting in a problem that the transparency of the resin becomes poor. The ratio C / A is more preferably from 2.95 to 21.42 μm, and even more preferably from 10.54 to 13.30 μm.
Here, the “surface area A obtained when the surface is viewed in plan” is the sum of the surface areas of the portions that become peaks or the valleys based on a certain height (threshold).
Further, the “surface convex volume C” is the sum of the volume of a part that becomes a peak or a part that becomes a valley based on a certain height (threshold).

[Average roughness of copper foil surface Rz]
The surface-treated copper foil of the present invention may be a non-roughened copper foil or a roughened copper foil on which roughened particles are formed, and the average roughness Rz of the TD on the roughened surface is 0.20-0. It is preferably 64 μm. With such a configuration, the peel strength becomes higher, the resin adheres well to the resin, and the transparency of the resin after the copper foil is removed by etching becomes higher. As a result, alignment and the like when mounting an IC chip through a positioning pattern that is visible through the resin can be made easier. When the average roughness Rz of TD is less than 0.20 μm, the roughening treatment on the surface of the copper foil may be insufficient, and there may be a problem that the resin cannot be sufficiently adhered. On the other hand, if the average roughness Rz of TD exceeds 0.64 μm, the unevenness of the resin surface after the copper foil is removed by etching may be increased, resulting in a problem that the transparency of the resin becomes poor. There is a fear. The average roughness Rz of the TD on the treated surface is more preferably 0.40 to 0.62 μm, still more preferably 0.46 to 0.55 μm.

In order to further improve the visibility effect of the present invention, the roughness (Rz) and the glossiness of the TD on the treated side surface of the copper foil before the surface treatment may be controlled. Specifically, the surface roughness (Rz) of TD of the copper foil before the surface treatment is preferably 0.20 to 0.55 μm, more preferably 0.20 to 0.42 μm. As such copper foil, rolling is performed by adjusting the oil film equivalent of the rolling oil (high gloss rolling), rolling is performed by adjusting the surface roughness of the rolling roll, or chemical polishing such as chemical etching or It can be produced by electropolishing in a phosphoric acid solution. Thus, it is easy to control the surface roughness (Rz) and the surface area of the copper foil after the treatment by setting the TD surface roughness (Rz) and the glossiness of the copper foil before the treatment within the above range. Can do.
Moreover, it is preferable that the 60 degree glossiness of TD is 400-710%, and, as for the copper foil before surface treatment, it is more preferable that it is 500-710%. If the 60 degree gloss of MD of the copper foil before the surface treatment is less than 400%, the transparency of the above resin may be worse than the case of 400% or more, and if it exceeds 710%, it will be manufactured. There is a risk that it will become difficult.
High gloss rolling can be performed by setting the oil film equivalent defined by the following formula to 13,000 to 24000 or less.
Oil film equivalent = {(rolling oil viscosity [cSt]) × (sheet feeding speed [mpm] + roll peripheral speed [mpm])} / {(roll biting angle [rad]) × (yield stress of material [kg / mm ² ])}
The rolling oil viscosity [cSt] is a kinematic viscosity at 40 ° C.
In order to set the oil film equivalent to 13,000 to 24,000, a known method such as using a low-viscosity rolling oil or slowing a sheet passing speed may be used.
The surface roughness of the rolling roll can be, for example, 0.01 to 0.25 μm in terms of arithmetic average roughness Ra (JIS B0601). When the value of the arithmetic average roughness Ra of the rolling roll is large, the TD roughness (Rz) on the surface of the copper foil before the surface treatment becomes large, and the 60-degree glossiness of the TD on the surface of the copper foil before the surface treatment is Tend to be lower. Further, when the value of the arithmetic average roughness Ra of the rolling roll is small, the TD roughness (Rz) of the surface of the copper foil before the surface treatment becomes small, and the TD 60 degree gloss of the surface of the copper foil before the surface treatment becomes small. Tend to be higher.
Chemical polishing is performed over a long period of time using an etching solution such as sulfuric acid-hydrogen peroxide-water system or ammonia-hydrogen peroxide-water system at a concentration lower than usual.

[Slope of brightness curve]
The surface-treated copper foil of the present invention is bonded to both sides of the polyimide base resin, then the copper foil on both sides is removed by etching, and a printed matter on which a line-shaped mark is printed is laid under the exposed polyimide substrate. Then, when the printed matter is photographed with a CCD camera through the polyimide substrate, the brightness at each observation point is measured along the direction perpendicular to the direction in which the observed line-shaped mark extends about the image obtained by photographing. In the produced observation point-lightness graph, the difference between the top average value Bt and the bottom average value Bb of the lightness curve generated from the end of the mark to the portion where the mark is not drawn is ΔB (ΔB = Bt−Bb), In the observation point-lightness graph, the intersection closest to the line-shaped mark among the intersections of the lightness curve and Bt is t1, and Bt is determined from the intersection of the lightness curve and Bt. In the depth range up to 0.1ΔB as a reference, when the intersection closest to the line mark is t2 among the intersections of the lightness curve and 0.1ΔB, Sv defined by the equation (1) is 3 .5 or more.
Sv = (ΔB × 0.1) / (t1-t2) (1)
In the observation position-lightness graph, the horizontal axis represents position information (pixel × 0.1), and the vertical axis represents the value of brightness (gradation).
Here, “top average value Bt of the lightness curve”, “bottom average value Bb of the lightness curve”, and “t1”, “t2”, and “Sv” described later will be described with reference to the drawings.
FIGS. 1A and 1B are schematic views for defining Bt and Bb when the mark width is about 0.3 mm. When the mark width is about 0.3 mm, a V-shaped brightness curve may be obtained as shown in FIG. 1A, or a brightness curve having a bottom as shown in FIG. 1B. . In any case, the “top average value Bt of the lightness curve” indicates the average value of lightness when measured at 5 locations (a total of 10 locations on both sides) at 30 μm intervals from the positions 50 μm away from the end positions on both sides of the mark. . On the other hand, the “bottom average value Bb of the lightness curve” indicates the minimum value of lightness at the tip of the V-shaped valley when the lightness curve is V-shaped as shown in FIG. When it has the bottom of (b), the value of the center part of about 0.3 mm is shown.
FIG. 2 is a schematic diagram that defines t1, t2, and Sv. “T1 (pixel × 0.1)” is a value indicating an intersection point closest to the line-shaped mark among intersection points of the lightness curve and Bt and a position of the intersection point (value on the horizontal axis of the observation point-lightness graph) ). “T2 (pixel × 0.1)” is the line-shaped mark among the intersections of the lightness curve and 0.1ΔB in the depth range from the intersection of the lightness curve and Bt to 0.1ΔB with reference to Bt. And the value (the value on the horizontal axis of the observation point-brightness graph) indicating the position of the intersection closest to. At this time, regarding the slope of the brightness curve indicated by the line connecting t1 and t2, Sv (gradation / pixel × 0.1) calculated by 0.1 ΔB in the y-axis direction and (t1−t2) in the x-axis direction. ). One pixel on the horizontal axis corresponds to a length of 10 μm. Further, Sv is measured on both sides of the mark, and a small value is adopted. Further, when the shape of the lightness curve is unstable and there are a plurality of the “intersections between the lightness curve and Bt”, the intersection closest to the mark is adopted.
In the image taken by the CCD camera, the brightness is high at the portion where the mark is not attached, but the brightness decreases as soon as the end of the mark is reached. If the visibility of the polyimide substrate is good, such a lowered state of brightness is clearly observed. On the other hand, if the visibility of the polyimide substrate is poor, the lightness does not suddenly drop from “high” to “low” in the vicinity of the mark end, but the state of decline is slow and the state of lightness decline is unclear. End up.
Based on such knowledge, the present invention is based on such a polyimide substrate from which the surface-treated copper foil of the present invention is bonded and removed, and a mark printed matter is placed under the polyimide substrate and photographed with a CCD camera over the polyimide substrate. The inclination of the lightness curve near the mark end portion drawn in the observation point-lightness graph obtained from the image is controlled. More specifically, the difference between the top average value Bt and the bottom average value Bb of the lightness curve is ΔB (ΔB = Bt−Bb), and the line of the intersections of the lightness curve and Bt in the observation point-lightness graph. In the depth range from the intersection of the lightness curve and Bt to 0.1 ΔB with reference to Bt, the value indicating the position of the intersection closest to the shape mark (the value on the horizontal axis of the observation point-lightness graph) is t1. When the value indicating the position of the intersection closest to the line-shaped mark among the intersections of the lightness curve and 0.1ΔB (the observation point—the value on the horizontal axis of the lightness graph) is t2, the above equation (1) Sv defined by is 3.5 or more. According to such a configuration, the discrimination power of the mark over the polyimide by the CCD camera is improved without being affected by the type and thickness of the substrate resin. For this reason, it is possible to produce a polyimide substrate with excellent visibility, and the positioning accuracy by marking when performing a predetermined treatment on the polyimide substrate in an electronic substrate manufacturing process or the like is improved, thereby improving the yield. can get. Sv is preferably 3.9 or more, more preferably 4.5 or more, even more preferably 5.0 or more, and even more preferably 5.5 or more. The upper limit of Sv is not particularly limited, but is, for example, 70 or less, 30 or less, 15 or less, and 10 or less. According to such a configuration, the boundary between the mark and the non-mark portion becomes clearer, the positioning accuracy is improved, the error due to the mark image recognition is reduced, and the alignment can be performed more accurately.

[Area ratio of copper foil surface]
The ratio B / A between the three-dimensional surface area B and the two-dimensional surface area A on the surface treatment side of the copper foil greatly affects the transparency of the resin. That is, if the surface roughness Rz is the same, the smaller the ratio B / A, the better the transparency of the resin. For this reason, as for the surface-treated copper foil of this invention, it is preferable that the said ratio B / A is 1.0-1.7, and it is more preferable that it is 1.0-1.6. Here, the ratio B / A between the three-dimensional surface area B and the two-dimensional surface area A of the surface on the surface treatment side is, for example, when the surface is roughened, and the surface area B of the roughened particles and the copper foil are copper. It can also be referred to as the ratio B / A to the area A obtained when viewed in plan from the foil surface side.

  By controlling the current density and plating time of the surface treatment during the surface treatment such as the formation of roughened particles, the surface state of the copper foil after the surface treatment and the form and formation density of the roughened particles are determined. Rz, glossiness, and area ratio B / A of the copper foil surface can be controlled.

  The surface-treated copper foil of the present invention can be bonded to a resin substrate from the surface-treated surface side to produce a laminate. The resin substrate is not particularly limited as long as it has characteristics applicable to a printed wiring board or the like. For example, a paper base phenol resin, a paper base epoxy resin, a synthetic fiber cloth base epoxy resin for rigid PWB Glass cloth / paper composite base material epoxy resin, glass cloth / glass nonwoven fabric composite base material epoxy resin and glass cloth base material epoxy resin, etc. are used, polyester film, polyimide film, liquid crystal polymer (LCP) film, Teflon for FPC (Registered trademark) film or the like can be used.

In the case of the rigid PWB, a prepreg is prepared by impregnating a base material such as a glass cloth with a resin and curing the resin to a semi-cured state. It can be carried out by superposing a copper foil on the prepreg from the opposite surface of the coating layer and heating and pressing. In the case of FPC, it is laminated on a copper foil under high temperature and high pressure without using an adhesive on a substrate such as a polyimide film, or a polyimide precursor is applied, dried, cured, etc. A laminated board can be manufactured by performing.
The thickness of the polyimide base resin is not particularly limited, but generally 25 μm or 50 μm can be mentioned.

  The laminate of the present invention can be used for various printed wiring boards (PWB) and is not particularly limited. For example, from the viewpoint of the number of layers of the conductor pattern, the single-sided PWB, the double-sided PWB, and the multilayer PWB (3 It is applicable to rigid PWB, flexible PWB (FPC), and rigid flex PWB from the viewpoint of the type of insulating substrate material.

(Laminated board and printed wiring board positioning method using the same)
A method for positioning the laminate of the surface-treated copper foil and the resin substrate of the present invention will be described. First, a laminate of a surface-treated copper foil and a resin substrate is prepared. As a specific example of the laminate of the surface-treated copper foil and the resin substrate according to the present invention, at least one of a main substrate, an attached circuit substrate, and a resin substrate such as polyimide used for electrically connecting them. In an electronic device composed of a flexible printed circuit board with copper wiring formed on the surface, a laminated board manufactured by accurately positioning the flexible printed circuit board and crimping it to the wiring ends of the main circuit board and the attached circuit board Is mentioned. That is, in this case, the laminate is a laminate in which the wiring end portions of the flexible printed circuit board and the main body substrate are bonded together by pressure bonding, or the wiring edge portions of the flexible printed circuit board and the circuit board are bonded together by pressure bonding. Laminated board. The laminated board has a mark formed of a part of the copper wiring and a separate material. The position of the mark is not particularly limited as long as it can be photographed by photographing means such as a CCD camera through the resin constituting the laminated plate.

  In the laminated plate thus prepared, when the above-described mark is photographed by the photographing means through the resin, the position of the mark can be detected satisfactorily. And the position of the said mark can be detected in this way, and based on the position of the said detected mark, the positioning of the laminated board of surface-treated copper foil and a resin substrate can be performed favorably. Similarly, when a printed wiring board is used as the laminated board, the photographing means can detect the position of the mark well by such a positioning method, and the printed wiring board can be positioned more accurately.

  Therefore, when one printed wiring board and another printed wiring board are connected, it is considered that the connection failure is reduced and the yield is improved. In addition, as a method of connecting one printed wiring board and another printed wiring board, connection via soldering or anisotropic conductive film (ACF), anisotropic conductive paste (Anisotropic Conductive Paste, A known connection method such as connection via ACP) or connection via a conductive adhesive can be used. In the present invention, the “printed wiring board” includes a printed wiring board, a printed circuit board, and a printed board on which components are mounted. Also, it is possible to manufacture a printed wiring board in which two or more printed wiring boards are connected by connecting two or more printed wiring boards according to the present invention, and at least one printed wiring board according to the present invention. One printed wiring board of the present invention or a printed wiring board not corresponding to the printed wiring board of the present invention can be connected, and an electronic apparatus can be manufactured using such a printed wiring board. In the present invention, “copper circuit” includes copper wiring. Furthermore, the printed wiring board of the present invention may be connected to a component to produce a printed wiring board. Further, at least one printed wiring board of the present invention is connected to another printed wiring board of the present invention or a printed wiring board not corresponding to the printed wiring board of the present invention. A printed wiring board in which two or more printed wiring boards are connected may be manufactured by connecting two or more printed wiring boards and components. Here, as “components”, connectors, LCDs (Liquid Crystal Display), electronic components such as glass substrates used in LCDs, ICs (Integrated Circuits), LSIs (Large scale integrated circuits), VLSIs (Very Large scale circuits). ), Electronic components including semiconductor integrated circuits such as ULSI (Ultra-Large Scale Integrated Circuit) (for example, IC chip, LSI chip, VLSI chip, ULSI chip), components for shielding electronic circuits, and covers on printed wiring boards, etc. Examples of the parts necessary to fix the are included.

The positioning method according to the embodiment of the present invention may include a step of moving a laminated board (including a laminated board of copper foil and a resin substrate and a printed wiring board). In the moving process, for example, it may be moved by a conveyor such as a belt conveyor or a chain conveyor, may be moved by a moving device provided with an arm mechanism, or may be moved by floating a laminated plate using gas. It may be moved by a moving means, a moving device or moving means (including a roller or a bearing) that moves a laminated plate by rotating an object such as a substantially cylindrical shape, a moving device or moving means that uses hydraulic pressure as a power source, Moving devices and moving means powered by air pressure, moving devices and moving means powered by motors, gantry moving linear guide stages, gantry moving air guide stages, stacked linear guide stages, linear motor drive stages, etc. It may be moved by a moving device or moving means having a stage. Moreover, you may perform the movement process by a well-known moving means.
The positioning method according to the embodiment of the present invention may be used for a surface mounter or a chip mounter.
Moreover, the printed wiring board which has the circuit provided on the resin board and the said resin board may be sufficient as the laminated board of the surface treatment copper foil and the resin board which are positioned in this invention. In that case, the mark may be the circuit.

In the present invention, “positioning” includes “detecting the position of a mark or an object”. In the present invention, “alignment” includes “after detecting the position of a mark or object, moving the mark or object to a predetermined position based on the detected position”.
In the printed wiring board, the circuit on the printed wiring board is used as a mark instead of the mark on the printed material, and the Sv value can be measured by photographing the circuit through a resin with a CCD camera. Also, for copper-clad laminates, after copper was etched into a line shape, the lined copper was used as a mark instead of a printed mark, and the lined copper was photographed with a CCD camera through the resin. Thus, the value of Sv can be measured.

  As Examples 1-8 and Comparative Examples 1-5, each copper foil was prepared, and the plating process was performed on the conditions of Table 2 as surface treatment on one surface. Moreover, the thing which does not perform a roughening process was also prepared. “No” in the “Roughening treatment” column of “Surface treatment” in Table 2 indicates that the surface treatment is not a roughening treatment, and “Yes” indicates that the surface treatment is a roughening treatment.

In addition, the rolled copper foil ("Tough pitch copper" in the "Kind" column of Table 1 indicates that it is a rolled copper foil) was produced as follows. After manufacturing a predetermined copper ingot and performing hot rolling, annealing and cold rolling of a 300-800 degreeC continuous annealing line were repeated, and the rolled sheet of 1-2 mm thickness was obtained. This rolled plate was annealed and recrystallized in a continuous annealing line at 300 to 800 ° C., and finally cold-rolled to the thickness shown in Table 1 to obtain a copper foil. “Tough pitch copper” in Table 1 indicates tough pitch copper standardized in JIS H3100 C1100.
Table 1 shows the points of the copper foil preparation process before the surface treatment. “High gloss rolling” means that the final cold rolling (cold rolling after the final recrystallization annealing) was performed at the value of the oil film equivalent. In addition, about Example 1, 2, the copper foil whose thickness of copper foil is 6 micrometers, 12 micrometers, and 35 micrometers was also manufactured.

Various evaluation was performed as follows about each sample of the Example and comparative example which were produced as mentioned above.
(1) Measurement of surface roughness (Rz);
About the copper foil after the surface treatment of each Example and Comparative Example, the surface roughness of the ten-point average roughness was measured in accordance with JIS B0601-1994 using a contact roughness meter Surfcoder SE-3C manufactured by Kosaka Laboratory Ltd. The surface was measured. Measurement standard length 0.8mm, evaluation length 4mm, cut-off value 0.25mm, feed rate 0.1mm / sec. The measurement position was changed 10 times in the direction (TD), and the value of 10 measurements was obtained.
In addition, the surface roughness (Rz) was calculated | required similarly about the copper foil before surface treatment.

(2) Measurement of the ratio C / A between the surface area A of the copper foil surface and the convex volume C;
About the surface treatment surface of the copper foil after the surface treatment of each Example and Comparative Example, the surface area A and the convex volume C obtained when viewed in a plane with an Olympus laser microscope OLS4000 were measured, and the ratio C / A was calculated. The value was determined from the conditions of an evaluation area of 647 μm × 646 μm and a cutoff value of zero. In addition, the measurement environmental temperature of the surface area A and convex part volume C obtained when it planarly views with a laser microscope was 23-25 degreeC.

(3) Area ratio of copper foil surface (B / A);
About the surface treatment surface of the copper foil after surface treatment of each Example and a comparative example, the measuring method by a laser microscope was used for the surface area of the copper foil surface. About the copper foil after the surface treatment of each Example and Comparative Example, an area equivalent to 647 μm × 646 μm at a magnification of 20 times of the treated surface using a Olympus laser microscope OLS4000 (surface area obtained when viewed in plan) A (actual data) Then, the three-dimensional surface area B at 417,953 μm ² ) was measured, and the calculation was performed by the method of three-dimensional surface area B ÷ two-dimensional surface area A = area ratio (B / A). In addition, the measurement environmental temperature of the three-dimensional surface area B with a laser microscope was 23-25 degreeC.

(4) Glossiness;
Incidence in a direction perpendicular to the rolling direction or the traveling direction of the electrolytic copper foil in the electrolytic copper foil manufacturing apparatus using a gloss meter PG-1 manufactured by Nippon Denshoku Industries Co., Ltd. conforming to JIS Z8741 The glossiness at an angle of 60 degrees was measured for the copper foil before the surface treatment.

(5) Inclination of brightness curve The copper foil was bonded to both sides of a polyimide film (50 μm Kaneka thickness, PIXIO for two-layer copper-clad laminate), and the copper foil was removed by etching (ferric chloride aqueous solution). A sample film was prepared. Subsequently, a printed material on which a line-shaped black mark is printed is laid under the sample film, the printed material is photographed with a CCD camera through the sample film, and the observed line-shaped mark is observed on the image obtained by photographing. In the observation point-lightness graph created by measuring the lightness at each observation point along the direction perpendicular to the direction of extension, the inclination (angle) of the lightness curve that occurs from the end of the mark to the part where the mark is not drawn It was measured. FIG. 3 is a schematic diagram showing the configuration of the photographing apparatus used at this time and the method of measuring the inclination of the brightness curve.
Further, ΔB, t1, t2, and Sv were measured by the following photographing apparatus as shown in FIG. One pixel on the horizontal axis corresponds to a length of 10 μm.
The photographing device has a CCD camera, a stage (white) on which a polyimide substrate is placed with a marked paper underneath, an illumination power source that irradiates light onto the photographing portion of the polyimide substrate, and a paper with a mark to be photographed. A transporter (not shown) for transporting the evaluation polyimide substrate placed below onto the stage is provided. The main specifications of the camera are as follows:
・ Photographing device: Sheet inspection device Mujken manufactured by Nireco Corporation
CCD camera: 8192 pixels (160 MHz), 1024 gradation digital (10 bits)
・ Power supply for lighting: High-frequency lighting power supply (power supply unit x 2)
・ Lighting: Fluorescent lamp (30W)
For the lightness shown in FIG. 3, 0 means “black”, lightness 255 means “white”, and the gray level from “black” to “white” (black and white shading, gray scale) Is divided into 256 gradations for display.

(6) Visibility (resin transparency);
The copper foil was bonded to both sides of a polyimide film (Kaneka thickness 50 μm), and the copper foil was removed by etching (ferric chloride aqueous solution) to prepare a sample film. A printed material (black circle with a diameter of 6 cm) was attached to one surface of the obtained resin layer, and the visibility of the printed material was judged from the opposite surface through the resin layer. “◎” indicates that the outline of the black circle of the printed material is clear when the length is 90% or more of the circumference, and “Clear” indicates that the outline of the black circle is clear when the length is 80% or more and less than 90% of the circumference. “O” (passed above), a black circle with a clear outline of 0 to less than 80% of the circumference and a broken outline were evaluated as “x” (failed).

(7) Peel strength (adhesive strength);
Based on IPC-TM-650, the normal peel strength was measured with a tensile tester Autograph 100, and a normal peel strength of 0.7 N / mm or more could be used for laminated substrates. In addition, the sample which bonded the surface treatment surface of the surface-treated copper foil which concerns on the Example and comparative example of this invention and the polyimide film with a thickness of 50 micrometers made from Kaneka was used for the measurement of this peel strength. At the time of measurement, the polyimide film is affixed to a hard substrate (stainless steel plate or synthetic resin plate (which does not have to be deformed during peel strength measurement)) with double-sided tape or with an instantaneous adhesive. Fixed by attaching. The unit of the peel strength value in the table is N / mm.

(8) Solder heat resistance evaluation;
Copper foil was bonded to both surfaces of a polyimide film (Kaneka thickness 50 μm). About the obtained double-sided laminated board, the test coupon based on JISC6471 was created. The prepared test coupon was exposed to high temperature and high humidity of 85 ° C. and 85% RH for 48 hours, and then floated in a solder bath at 300 ° C. to evaluate solder heat resistance. After the solder heat resistance test, at the interface between the copper foil roughening surface and the polyimide resin adhesion surface, the area where the interface discolored due to blistering in an area of 5% or more of the copper foil area in the test coupon is x (failed), area When the color change was less than 5%, the case was evaluated as ◯, and the case where no color change occurred was evaluated as ◎.

(9) Yield Copper foil was bonded to both sides of a polyimide film (Kaneka thickness 50 μm), and the copper foil was etched (ferric chloride aqueous solution) to create an FPC with a circuit width of L / S 30 μm / 30 μm. . After that, an attempt was made to detect a 20 μm × 20 μm square mark with a CCD camera through polyimide. “◎” when 9 times or more out of 10 times can be detected, “◯” when 7 to 8 times can be detected, “△” when 6 times can be detected, and when 5 times or less can be detected. Is “×”.
In the printed wiring board or the copper-clad laminate, the above-mentioned (1) surface roughness (Rz) and (2) the surface area of the copper foil surface are obtained by dissolving and removing the resin. Measurement of ratio C / A of A and convex part volume C, (3) Area ratio (A / B) of the copper foil surface can be measured.
Tables 1 and 2 show the conditions and evaluation of the above tests.

(Evaluation results)
In Examples 1 to 8, the ratio C / A between the surface area A obtained when the surface is viewed in plan and the convex volume C of the surface is in the range of 2.11 to 23.91, and Sv is The visibility, peel strength, solder heat resistance evaluation, and yield were good. In addition, the copper foils manufactured for Examples 1 and 2 and having thicknesses of 6 μm, 12 μm, and 35 μm had the same results as in Examples 1 and 2 having a thickness of 18 μm. That is, the ratio of the surface area A obtained when the surfaces of the copper foils manufactured for Examples 1 and 2 having a thickness of 6 μm, 12 μm, and 35 μm in plan view to the convex volume C of the surface C / A was in the range of 2.11 to 23.91, Sv was 3.5 or more, and visibility, peel strength, solder heat resistance evaluation and yield were good.
In Comparative Example 1, the ratio C / A between the surface area A obtained when the surface was viewed in plan and the convex volume C of the surface was less than 2.11, and the peel strength and solder heat resistance were poor. .
In Comparative Examples 2, 3 and 5, the ratio C / A between the surface area A obtained when the surface is viewed in plan and the convex volume C of the surface exceeds 23.91, and Sv is less than 3.5. Yes, visibility was poor. In Comparative Example 4, Sv was less than 3.5, and the visibility was poor.
FIG. 4 shows (a) Comparative Example 1, (b) Example 1, (c) Example 2, (d) Example 3, (e) Example 4, and (f) in the Rz evaluation. The SEM observation photograph on the copper foil surface of Example 5, (g) Example 6, (h) Example 7, (i) Example 8, (j) Comparative Example 2, (k) Comparative Example 3 is shown, respectively.

Also shows the production conditions of Ru electrodeposition Kaidohaku for use in the present invention are shown below.
<Electrolyte composition>
Copper: 90-110 g / L
Sulfuric acid: 90-110 g / L
Chlorine: 50-100ppm
Leveling agent 1 (bis (3sulfopropyl) disulfide): 10 to 30 ppm
Leveling agent 2 (amine compound): 10 to 30 ppm
As the amine compound, an amine compound having the following chemical formula can be used.

Such ternary copper - cobalt - general bath and plating conditions for forming the nickel alloy plating are as follows:
Plating bath composition: Cu 10-20 g / L, Co 1-10 g / L, Ni 1-10 g / L
pH: 1-4
Temperature: 30-50 ° C
Current density D _k : 35 to 40 A / dm ²
Plating time: 1.0 to 1.7 seconds

In addition, cobalt - conditions of the nickel alloy plating are as follows:
Plating bath composition: Co 1-20 g / L, Ni 1-20 g / L
pH: 1.5-3.5
Temperature: 30-80 ° C

Conditions of the zinc plating is as follows:
Plating bath composition: Zn 100 to 300 g / L
pH: 3-4
Temperature: 50-60 ° C

To further enhance the effect of the visibility of the invention, to control the roughness (Rz) and gloss of the TD process side of the surface of the copper foil before surface treatment. Specifically, the TD surface roughness (Rz) of the copper foil before the surface treatment is 0 . 20~0.55μm, it is good Mashiku is 0.20~0.42μm. As such copper foil, rolling is performed by adjusting the oil film equivalent of the rolling oil (high gloss rolling), rolling is performed by adjusting the surface roughness of the rolling roll, or chemical polishing such as chemical etching or It prepared by electrolytic polishing of phosphoric acid solution. Thus, it is easy to control the surface roughness (Rz) and the surface area of the copper foil after the treatment by setting the TD surface roughness (Rz) and the glossiness of the copper foil before the treatment within the above range. Can do.
Further, the copper foil before surface treatment, 60 degree gloss of TD is 400 to 710%, and even good preferable and from 500 to 710%. If the 60 degree gloss of MD of the copper foil before the surface treatment is less than 400%, the transparency of the above resin may be worse than the case of 400% or more, and if it exceeds 710%, it will be manufactured. There is a risk that it will become difficult.
High gloss rolling can be performed by setting the oil film equivalent defined by the following formula to 13,000 to 24000 or less.
Oil film equivalent = {(rolling oil viscosity [cSt]) × (sheet feeding speed [mpm] + roll peripheral speed [mpm])} / {(roll biting angle [rad]) × (yield stress of material [kg / mm ² ])}
The rolling oil viscosity [cSt] is a kinematic viscosity at 40 ° C.
In order to set the oil film equivalent to 13,000 to 24,000, a known method such as using a low-viscosity rolling oil or slowing a sheet passing speed may be used.
The surface roughness of the rolling roll can be, for example, 0.01 to 0.25 μm in terms of arithmetic average roughness Ra (JIS B0601). When the value of the arithmetic average roughness Ra of the rolling roll is large, the TD roughness (Rz) on the surface of the copper foil before the surface treatment becomes large, and the 60-degree glossiness of the TD on the surface of the copper foil before the surface treatment is Tend to be lower. Further, when the value of the arithmetic average roughness Ra of the rolling roll is small, the TD roughness (Rz) of the surface of the copper foil before the surface treatment becomes small, and the TD 60 degree gloss of the surface of the copper foil before the surface treatment becomes small. Tend to be higher.
Chemical polishing is performed over a long period of time using an etching solution such as sulfuric acid-hydrogen peroxide-water system or ammonia-hydrogen peroxide-water system at a concentration lower than usual.

  The present invention relates to a surface-treated copper foil and a laminate using the surface-treated copper foil, and in particular, a surface-treated copper foil suitable for a field where transparency of the remaining resin after etching the copper foil is required, and a laminate using the same. Regarding the board.

  In a small electronic device such as a smartphone or a tablet PC, a flexible printed wiring board (hereinafter referred to as FPC) is adopted because of easy wiring and light weight. In recent years, with the enhancement of functions of these electronic devices, the signal transmission speed has been increased, and impedance matching has become an important factor in FPC. As a measure for impedance matching with respect to an increase in signal capacity, a resin insulation layer (for example, polyimide) serving as a base of an FPC has been increased in thickness. In addition, the demand for higher wiring density has further increased the number of FPC layers. On the other hand, processing such as bonding to a liquid crystal substrate and mounting of an IC chip is performed on the FPC, but the alignment at this time is the resin insulation remaining after etching the copper foil in the laminate of the copper foil and the resin insulating layer The visibility of the resin insulation layer is important because it is performed through a positioning pattern that is visible through the layer.

  Moreover, the copper clad laminated board which is a laminated board of copper foil and a resin insulating layer can also be manufactured even if it uses the rolled copper foil by which roughening plating was given to the surface. This rolled copper foil usually uses tough pitch copper (oxygen content of 100 to 500 ppm by weight) or oxygen-free copper (oxygen content of 10 ppm by weight or less) as a raw material, and after hot rolling these ingots, It is manufactured by repeating cold rolling and annealing to a thickness.

As such a technique, for example, in Patent Document 1, a polyimide film and a low-roughness copper foil are laminated, and a light transmittance at a wavelength of 600 nm of the film after copper foil etching is 40% or more, a haze value. An invention relating to a copper clad laminate having (HAZE) of 30% or less and an adhesive strength of 500 N / m or more is disclosed.
Further, Patent Document 2 has an insulating layer in which a conductive layer made of electrolytic copper foil is laminated, and the light transmittance of the insulating layer in the etching region when the circuit is formed by etching the conductive layer is 50% or more. In a flexible printed wiring board for chip-on-flex (COF), the electrolytic copper foil has a rust-proofing layer made of a nickel-zinc alloy on an adhesive surface bonded to an insulating layer, and the surface roughness (Rz) of the adhesive surface ) Is 0.05 to 1.5 μm, and the specular gloss at an incident angle of 60 ° is 250 or more, and an invention relating to a flexible printed wiring board for COF is disclosed.
Moreover, in patent document 3, in the processing method of the copper foil for printed circuits, after the roughening process by copper-cobalt-nickel alloy plating on the surface of copper foil, a cobalt-nickel alloy plating layer is formed, and also zinc-nickel An invention relating to a method for treating a copper foil for printed circuit, characterized by forming an alloy plating layer is disclosed.

JP 2004-98659 A WO2003 / 096776 Japanese Patent No. 2849059

In Patent Document 1, a low-roughness copper foil obtained by improving adhesion with an organic treatment agent after blackening treatment or plating treatment is broken due to fatigue in applications where flexibility is required for a copper-clad laminate. May be inferior in resin transparency.
Moreover, in patent document 2, the roughening process is not made and the adhesive strength of copper foil and resin is low and inadequate in uses other than the flexible printed wiring board for COF.
Furthermore, in the processing method described in Patent Document 3, Cu-Co-Ni fine processing on the copper foil was possible, but the resin after bonding the copper foil with the resin and removing it by etching was excellent. Transparency is not realized.
The present invention provides a surface-treated copper foil that adheres well to a resin and is excellent in the transparency of a resin after the copper foil is removed by etching, and a laminate using the same.

  As a result of intensive studies, the present inventors have obtained a copper foil in which the ratio C / A between the surface area A obtained when the surface is viewed in plan and the convex volume C on the surface is controlled within a predetermined range by surface treatment. An observation point-brightness obtained from an image of the mark portion obtained by placing the printed matter with the mark on the polyimide substrate removed from the processing surface side and pasting the polyimide substrate through the polyimide substrate. Paying attention to the slope of the brightness curve near the mark edge drawn in the graph, controlling the slope of the brightness curve is not affected by the type of substrate resin film or the thickness of the substrate resin film, It has been found that it affects the resin transparency after etching.

The present invention completed on the basis of the above knowledge is, in one aspect, surface treatment is performed on at least one surface, and a surface area A obtained when viewing the surface on which the surface treatment is performed, A surface-treated copper foil having a ratio C / A to the convex volume C of the surface of 2.11 to 23.91, wherein both surfaces of the polyimide resin substrate are formed from the surface side where the surface treatment is performed on the copper foil. Then, the copper foils on both sides are removed by etching, and a printed matter on which a line-shaped mark is printed is laid under the exposed polyimide substrate, and the printed matter is photographed with a CCD camera through the polyimide substrate. The observation point-brightness group is obtained by measuring the brightness at each observation point along the direction perpendicular to the direction in which the observed line-shaped mark extends for the image obtained by the photographing. The difference between the top average value Bt and the bottom average value Bb of the brightness curve generated from the end of the mark to the portion where the mark is not drawn is ΔB (ΔB = Bt−Bb), and the observation point-lightness graph , The value indicating the position of the intersection closest to the line-shaped mark among the intersections of the lightness curve and Bt is t1, and the depth range from the intersection of the lightness curve and Bt to 0.1 ΔB with reference to Bt , When the value indicating the position of the intersection closest to the line-shaped mark among the intersections of the lightness curve and 0.1 ΔB is t2, Sv defined by the following equation (1) is 3.5 or more It becomes.
Sv = (ΔB × 0.1) / (t1-t2) (1)

  In another embodiment of the surface-treated copper foil according to the present invention, the ratio C / A is 2.95 to 21.42.

  In still another embodiment of the surface-treated copper foil according to the present invention, Sv defined by the formula (1) in the brightness curve is 3.9 or more.

  In still another embodiment of the surface-treated copper foil according to the present invention, Sv defined by the formula (1) in the brightness curve is 5.0 or more.

  In still another embodiment of the surface-treated copper foil according to the present invention, the TD ten-point average roughness Rz of the surface is 0.20 to 0.64 μm.

  In still another embodiment of the surface-treated copper foil according to the present invention, the TD ten-point average roughness Rz of the surface is 0.40 to 0.62 μm.

  In still another embodiment of the surface-treated copper foil according to the present invention, the ratio B / A between the three-dimensional surface area B of the surface and the two-dimensional surface area (surface area obtained when the surface is viewed in plan) A is 1 0.0 to 1.7.

  In still another embodiment of the surface-treated copper foil according to the present invention, the B / A is 1.0 to 1.6.

  In still another aspect, the present invention is a laminated plate configured by laminating the surface-treated copper foil of the present invention and a resin substrate.

  In still another aspect, the present invention is a printed wiring board using the surface-treated copper foil of the present invention.

  In still another aspect, the present invention is an electronic device using the printed wiring board of the present invention.

  In still another aspect, the present invention is a method of manufacturing a printed wiring board in which two or more printed wiring boards are connected by connecting two or more printed wiring boards of the present invention.

  In yet another aspect, the present invention includes a step of connecting at least one printed wiring board of the present invention and another printed wiring board of the present invention or a printed wiring board not corresponding to the printed wiring board of the present invention, This is a method for manufacturing a printed wiring board in which two or more printed wiring boards are connected.

  In still another aspect, the present invention is an electronic apparatus using one or more printed wiring boards to which at least one printed wiring board of the present invention is connected.

  In still another aspect, the present invention is a method for manufacturing a printed wiring board, including at least a step of connecting the printed wiring board of the present invention and a component.

  In yet another aspect of the present invention, the step of connecting at least one printed wiring board of the present invention to another printed wiring board of the present invention or a printed wiring board not corresponding to the printed wiring board of the present invention, and A method of manufacturing a printed wiring board having two or more printed wiring boards connected, comprising at least a step of connecting a printed wiring board of the present invention or a printed wiring board having two or more printed wiring boards of the present invention connected thereto and a component. It is.

  ADVANTAGE OF THE INVENTION According to this invention, the surface-treated copper foil excellent in transparency of resin after adhere | attaching resin favorably and removing copper foil by an etching, and a laminated board using the same can be provided.

It is a schematic diagram which defines Bt and Bb. It is a schematic diagram which defines t1, t2, and Sv. It is a schematic diagram showing the structure of an imaging device and the measuring method of the inclination of a lightness curve in the case of evaluation of the lightness curve inclination. It is a SEM observation photograph of the copper foil surface of the comparative example 1 in the case of Rz evaluation. It is a SEM observation photograph of the copper foil surface of Example 1 in the case of Rz evaluation. It is a SEM observation photograph of the copper foil surface of Example 2 in the case of Rz evaluation. It is a SEM observation photograph of the copper foil surface of Example 3 in the case of Rz evaluation. It is a SEM observation photograph of the copper foil surface of Example 4 in the case of Rz evaluation. It is a SEM observation photograph on the copper foil surface of Example 5 in the case of Rz evaluation. It is a SEM observation photograph of the copper foil surface of Example 6 in the case of Rz evaluation. It is a SEM observation photograph of the copper foil surface of Example 7 in the case of Rz evaluation. It is a SEM observation photograph of the copper foil surface of Example 8 in the case of Rz evaluation. It is a SEM observation photograph of the copper foil surface of the comparative example 2 in the case of Rz evaluation. It is a SEM observation photograph of the copper foil surface of the comparative example 3 in the case of Rz evaluation.

[Form and manufacturing method of surface-treated copper foil]
The copper foil used in the present invention is useful for a copper foil used by making a laminate by bonding to a resin substrate and removing it by etching.
The copper foil used in the present invention may be either an electrolytic copper foil or a rolled copper foil. Usually, the surface of the copper foil that adheres to the resin substrate, that is, the surface on the surface treatment side, has the shape of the surface of the copper foil after degreasing for the purpose of improving the peel strength of the copper foil after lamination. A roughening treatment for performing electrodeposition may be performed. Although the electrolytic copper foil has irregularities at the time of manufacture, the irregularities can be further increased by enhancing the convex portions of the electrolytic copper foil by roughening treatment. In the present invention, this roughening treatment can be performed by copper-cobalt-nickel alloy plating, copper-nickel-phosphorus alloy plating, or the like. Ordinary copper plating or the like may be performed as a pretreatment before roughening, and ordinary copper plating or the like may be performed as a finishing treatment after roughening in order to prevent electrodeposits from dropping off. The content of treatment may be somewhat different between the rolled copper foil and the electrolytic copper foil .
The copper foil used in the present invention may be subjected to a roughening treatment, or the roughening treatment may be omitted and a heat-resistant plating layer or a rust-proof plating layer may be applied to the surface. As a treatment for omitting the roughening treatment and applying a heat-resistant plating layer or a rust-proof plating layer to the surface, a plating treatment using a Ni plating bath under the following conditions can be used.
・ Ni: 20g / L
-PH: 2.5
・ Bath temperature: 40 ℃
The thickness of the copper foil used in the present invention is not particularly limited, but is, for example, 1 μm or more, 2 μm or more, 3 μm or more, 5 μm or more, for example, 3000 μm or less, 1500 μm or less, 800 μm or less, 300 μm or less, 150 μm or less. 100 μm or less, 70 μm or less, 50 μm or less, or 40 μm or less.
The rolled copper foil that can be used in the present invention contains one or more elements such as Ag, Sn, In, Ti, Zn, Zr, Fe, P, Ni, Si, Te, Cr, Nb, V, and B. Copper alloy foil is also included. When the concentration of the above elements increases (for example, 10% by mass or more in total), the conductivity may decrease. The conductivity of the rolled copper foil is preferably 50% IACS or more, more preferably 60% IACS or more, and still more preferably 80% IACS or more.

Moreover, the manufacturing conditions of the electrolytic copper foil used for this invention are shown below.
<Electrolyte composition>
Copper: 90-110 g / L
Sulfuric acid: 90-110 g / L
Chlorine: 50-100ppm
Leveling agent 1 (bis (3sulfopropyl) disulfide): 10 to 30 ppm
Leveling agent 2 (amine compound): 10 to 30 ppm
As the amine compound, an amine compound having the following chemical formula can be used.

(In the above chemical formula, R ₁ and R ₂ are selected from the group consisting of a hydroxyalkyl group, an ether group, an aryl group, an aromatic substituted alkyl group, an unsaturated hydrocarbon group, and an alkyl group.)

<Production conditions>
Current density: 70 to 100 A / dm ²
Electrolyte temperature: 50-60 ° C
Electrolyte linear velocity: 3-5 m / sec
Electrolysis time: 0.5 to 10 minutes

Copper as roughening treatment - cobalt - nickel alloy plating, by electrolytic plating, coating weight is to be the 15~40mg / dm ² of copper -100~3000μg / dm ² of cobalt -100~1500μg / dm ² of nickel It can be carried out so as to form a ternary alloy layer. If the amount of deposited Co is less than 100 μg / dm ² , the heat resistance may deteriorate and the etching property may deteriorate. When the amount of Co deposition exceeds 3000 μg / dm ² , it is not preferable when the influence of magnetism must be taken into account, etching spots may occur, and acid resistance and chemical resistance may deteriorate. If the Ni adhesion amount is less than 100 μg / dm ² , the heat resistance may deteriorate. On the other hand, when the Ni adhesion amount exceeds 1500 μg / dm ² , the etching residue may increase. A preferable Co adhesion amount is 1000 to 2500 μg / dm ² , and a preferable nickel adhesion amount is 500 to 1200 μg / dm ² . Here, the etching stain means that Co remains without being dissolved when etched with copper chloride, and the etching residue means that Ni remains without being dissolved when alkaline etching is performed with ammonium chloride. It means that.

The general bath and plating conditions for forming such ternary copper-cobalt-nickel alloy plating are as follows:
Plating bath composition: Cu 10-20 g / L, Co 1-10 g / L, Ni 1-10 g / L
pH: 1-4
Temperature: 30-50 ° C
Current density Dk: 35 to 40 A / dm ²
Plating time: 1.0 to 1.7 seconds

After the roughening treatment, a cobalt-nickel alloy plating layer of nickel having an adhesion amount of 200 to 3000 μg / dm ² and cobalt-100 to 700 μg / dm ² can be formed on the roughened surface. This treatment can be regarded as a kind of rust prevention treatment in a broad sense. This cobalt-nickel alloy plating layer needs to be performed to such an extent that the adhesive strength between the copper foil and the substrate is not substantially reduced. If the amount of cobalt adhesion is less than 200 μg / dm ² , the heat-resistant peel strength is lowered, and the oxidation resistance and chemical resistance may be deteriorated. As another reason, if the amount of cobalt is small, the treated surface becomes reddish, which is not preferable. When the cobalt deposition amount exceeds 3000μg / dm ^2, it is not preferable in cases where it is necessary to taken into account the influence of the magnetic, may etching stain may occur, also sometimes acid resistance and chemical resistance are deteriorated. A preferable cobalt adhesion amount is 500 to 2500 μg / dm ² . On the other hand, if the nickel adhesion amount is less than 100 μg / dm ² , the heat-resistant peel strength is lowered, and the oxidation resistance and chemical resistance may be deteriorated. When nickel exceeds 1300 microgram / dm < ² >, alkali etching property will worsen. A preferable nickel adhesion amount is 200 to 1200 μg / dm ² .

The conditions for cobalt-nickel alloy plating are as follows:
Plating bath composition: Co 1-20 g / L, Ni 1-20 g / L
pH: 1.5-3.5
Temperature: 30-80 ° C

According to the present invention, a zinc plating layer having an adhesion amount of 30 to 250 μg / dm ² is further formed on the cobalt-nickel alloy plating. If the zinc adhesion amount is less than 30 μg / dm ² , the heat deterioration rate improving effect may be lost. On the other hand, when the zinc adhesion amount exceeds 250 μg / dm ² , the hydrochloric acid deterioration rate may be extremely deteriorated. Preferably, the zinc adhesion amount is 30 to 240 μg / dm ² , more preferably 80 to 220 μg / dm ² .

The galvanizing conditions are as follows:
Plating bath composition: Zn 100 to 300 g / L
pH: 3-4
Temperature: 50-60 ° C

  A zinc alloy plating layer such as zinc-nickel alloy plating may be formed instead of the zinc plating layer, and a rust prevention layer may be formed on the outermost surface by chromate treatment or application of a silane coupling agent. Good.

  In the surface-treated copper foil of the present invention, the ratio C / A of the surface area A and the convex volume C is controlled by adjusting the current density of the roughened particles and the plating time as described above. . When the plating process is performed at a high current density, small rough particles are obtained, and when the plating process is performed at a low current density, large rough particles are obtained. Since the number of particles formed under these conditions is determined by the plating time, the convex volume C is determined by a combination of the current density and the plating time.

[Ratio C / A of surface area A of copper foil surface and convex volume C]
In the surface-treated copper foil of the present invention, the ratio C / A between the surface area A obtained when the surface is viewed in plan and the convex volume C of the surface is 2.11 to 23.91 on at least one surface. Is controlled. With such a configuration, the peel strength is increased and the resin is satisfactorily bonded to the resin, and the transparency of the resin after the copper foil is removed by etching is increased. As a result, alignment and the like when mounting an IC chip through a positioning pattern that is visible through the resin are facilitated. When the ratio C / A is less than 2.11 μm, the roughening treatment on the surface of the copper foil becomes insufficient, causing a problem that the resin cannot be sufficiently bonded. On the other hand, if the ratio C / A is more than 23.91 μm, the unevenness of the resin surface after the copper foil is removed by etching increases, resulting in a problem that the transparency of the resin becomes poor. The ratio C / A is more preferably from 2.95 to 21.42 μm, and even more preferably from 10.54 to 13.30 μm.
Here, the “surface area A obtained when the surface is viewed in plan” is the sum of the surface areas of the portions that become peaks or the valleys based on a certain height (threshold).
Further, the “surface convex volume C” is the sum of the volume of a part that becomes a peak or a part that becomes a valley based on a certain height (threshold).

[Average roughness of copper foil surface Rz]
The surface-treated copper foil of the present invention may be a non-roughened copper foil or a roughened copper foil on which roughened particles are formed, and the average roughness Rz of the TD on the roughened surface is 0.20-0. It is preferably 64 μm. With such a configuration, the peel strength becomes higher, the resin adheres well to the resin, and the transparency of the resin after the copper foil is removed by etching becomes higher. As a result, alignment and the like when mounting an IC chip through a positioning pattern that is visible through the resin can be made easier. When the average roughness Rz of TD is less than 0.20 μm, the roughening treatment on the surface of the copper foil may be insufficient, and there may be a problem that the resin cannot be sufficiently adhered. On the other hand, if the average roughness Rz of TD exceeds 0.64 μm, the unevenness of the resin surface after the copper foil is removed by etching may be increased, resulting in a problem that the transparency of the resin becomes poor. There is a fear. The average roughness Rz of the TD on the treated surface is more preferably 0.40 to 0.62 μm, still more preferably 0.46 to 0.55 μm.

In order to further improve the visibility effect of the present invention, the TD roughness (Rz) and glossiness of the surface of the copper foil before the surface treatment on the treatment side are controlled. Specifically, the TD surface roughness (Rz) of the copper foil before the surface treatment is 0.20 to 0.55 μm, preferably 0.20 to 0.42 μm. As such copper foil, rolling is performed by adjusting the oil film equivalent of the rolling oil (high gloss rolling), rolling is performed by adjusting the surface roughness of the rolling roll, or chemical polishing such as chemical etching or It is prepared by electropolishing in a phosphoric acid solution. Thus, it is easy to control the surface roughness (Rz) and the surface area of the copper foil after the treatment by setting the TD surface roughness (Rz) and the glossiness of the copper foil before the treatment within the above range. Can do.
The copper foil before the surface treatment has a TD 60-degree glossiness of 400 to 710%, preferably 500 to 710%. If the 60 degree gloss of MD of the copper foil before the surface treatment is less than 400%, the transparency of the above resin may be worse than the case of 400% or more, and if it exceeds 710%, it will be manufactured. There is a risk that it will become difficult.
High gloss rolling can be performed by setting the oil film equivalent defined by the following formula to 13,000 to 24000 or less.
Oil film equivalent = {(rolling oil viscosity [cSt]) × (sheet feeding speed [mpm] + roll peripheral speed [mpm])} / {(roll biting angle [rad]) × (yield stress of material [kg / mm ² ])}
The rolling oil viscosity [cSt] is a kinematic viscosity at 40 ° C.
In order to set the oil film equivalent to 13,000 to 24,000, a known method such as using a low-viscosity rolling oil or slowing a sheet passing speed may be used.
The surface roughness of the rolling roll can be, for example, 0.01 to 0.25 μm in terms of arithmetic average roughness Ra (JIS B0601). When the value of the arithmetic average roughness Ra of the rolling roll is large, the TD roughness (Rz) on the surface of the copper foil before the surface treatment becomes large, and the 60-degree glossiness of the TD on the surface of the copper foil before the surface treatment is Tend to be lower. Further, when the value of the arithmetic average roughness Ra of the rolling roll is small, the TD roughness (Rz) of the surface of the copper foil before the surface treatment becomes small, and the TD 60 degree gloss of the surface of the copper foil before the surface treatment becomes small. Tend to be higher.
Chemical polishing is performed over a long period of time using an etching solution such as sulfuric acid-hydrogen peroxide-water system or ammonia-hydrogen peroxide-water system at a concentration lower than usual.

[Slope of brightness curve]
The surface-treated copper foil of the present invention is bonded to both sides of the polyimide base resin, then the copper foil on both sides is removed by etching, and a printed matter on which a line-shaped mark is printed is laid under the exposed polyimide substrate. Then, when the printed matter is photographed with a CCD camera through the polyimide substrate, the brightness at each observation point is measured along the direction perpendicular to the direction in which the observed line-shaped mark extends about the image obtained by photographing. In the produced observation point-lightness graph, the difference between the top average value Bt and the bottom average value Bb of the lightness curve generated from the end of the mark to the portion where the mark is not drawn is ΔB (ΔB = Bt−Bb), In the observation point-lightness graph, the intersection closest to the line-shaped mark among the intersections of the lightness curve and Bt is t1, and Bt is determined from the intersection of the lightness curve and Bt. In the depth range up to 0.1ΔB as a reference, when the intersection closest to the line mark is t2 among the intersections of the lightness curve and 0.1ΔB, Sv defined by the equation (1) is 3 .5 or more.
Sv = (ΔB × 0.1) / (t1-t2) (1)
In the observation position-lightness graph, the horizontal axis represents position information (pixel × 0.1), and the vertical axis represents the value of brightness (gradation).
Here, “top average value Bt of the lightness curve”, “bottom average value Bb of the lightness curve”, and “t1”, “t2”, and “Sv” described later will be described with reference to the drawings.
FIGS. 1A and 1B are schematic views for defining Bt and Bb when the mark width is about 0.3 mm. When the mark width is about 0.3 mm, a V-shaped brightness curve may be obtained as shown in FIG. 1A, or a brightness curve having a bottom as shown in FIG. 1B. . In any case, the “top average value Bt of the lightness curve” indicates the average value of lightness when measured at 5 locations (a total of 10 locations on both sides) at 30 μm intervals from the positions 50 μm away from the end positions on both sides of the mark. . On the other hand, the “bottom average value Bb of the lightness curve” indicates the minimum value of lightness at the tip of the V-shaped valley when the lightness curve is V-shaped as shown in FIG. When it has the bottom of (b), the value of the center part of about 0.3 mm is shown.
FIG. 2 is a schematic diagram that defines t1, t2, and Sv. “T1 (pixel × 0.1)” is a value indicating an intersection point closest to the line-shaped mark among intersection points of the lightness curve and Bt and a position of the intersection point (value on the horizontal axis of the observation point-lightness graph) ). “T2 (pixel × 0.1)” is the line-shaped mark among the intersections of the lightness curve and 0.1ΔB in the depth range from the intersection of the lightness curve and Bt to 0.1ΔB with reference to Bt. And the value (the value on the horizontal axis of the observation point-brightness graph) indicating the position of the intersection closest to. At this time, regarding the slope of the brightness curve indicated by the line connecting t1 and t2, Sv (gradation / pixel × 0.1) calculated by 0.1 ΔB in the y-axis direction and (t1−t2) in the x-axis direction. ). One pixel on the horizontal axis corresponds to a length of 10 μm. Further, Sv is measured on both sides of the mark, and a small value is adopted. Further, when the shape of the lightness curve is unstable and there are a plurality of the “intersections between the lightness curve and Bt”, the intersection closest to the mark is adopted.
In the image taken by the CCD camera, the brightness is high at the portion where the mark is not attached, but the brightness decreases as soon as the end of the mark is reached. If the visibility of the polyimide substrate is good, such a lowered state of brightness is clearly observed. On the other hand, if the visibility of the polyimide substrate is poor, the lightness does not suddenly drop from “high” to “low” in the vicinity of the mark end, but the state of decline is slow and the state of lightness decline is unclear. End up.
Based on such knowledge, the present invention is based on such a polyimide substrate from which the surface-treated copper foil of the present invention is bonded and removed, and a mark printed matter is placed under the polyimide substrate and photographed with a CCD camera over the polyimide substrate. The inclination of the lightness curve near the mark end portion drawn in the observation point-lightness graph obtained from the image is controlled. More specifically, the difference between the top average value Bt and the bottom average value Bb of the lightness curve is ΔB (ΔB = Bt−Bb), and the line of the intersections of the lightness curve and Bt in the observation point-lightness graph. In the depth range from the intersection of the lightness curve and Bt to 0.1 ΔB with reference to Bt, the value indicating the position of the intersection closest to the shape mark (the value on the horizontal axis of the observation point-lightness graph) is t1. When the value indicating the position of the intersection closest to the line-shaped mark among the intersections of the lightness curve and 0.1ΔB (the observation point—the value on the horizontal axis of the lightness graph) is t2, the above equation (1) Sv defined by is 3.5 or more. According to such a configuration, the discrimination power of the mark over the polyimide by the CCD camera is improved without being affected by the type and thickness of the substrate resin. For this reason, it is possible to produce a polyimide substrate with excellent visibility, and the positioning accuracy by marking when performing a predetermined treatment on the polyimide substrate in an electronic substrate manufacturing process or the like is improved, thereby improving the yield. can get. Sv is preferably 3.9 or more, more preferably 4.5 or more, even more preferably 5.0 or more, and even more preferably 5.5 or more. The upper limit of Sv is not particularly limited, but is, for example, 70 or less, 30 or less, 15 or less, and 10 or less. According to such a configuration, the boundary between the mark and the non-mark portion becomes clearer, the positioning accuracy is improved, the error due to the mark image recognition is reduced, and the alignment can be performed more accurately.

[Area ratio of copper foil surface]
The ratio B / A between the three-dimensional surface area B and the two-dimensional surface area A on the surface treatment side of the copper foil greatly affects the transparency of the resin. That is, if the surface roughness Rz is the same, the smaller the ratio B / A, the better the transparency of the resin. For this reason, as for the surface-treated copper foil of this invention, it is preferable that the said ratio B / A is 1.0-1.7, and it is more preferable that it is 1.0-1.6. Here, the ratio B / A between the three-dimensional surface area B and the two-dimensional surface area A of the surface on the surface treatment side is, for example, when the surface is roughened, and the surface area B of the roughened particles and the copper foil are copper. It can also be referred to as the ratio B / A to the area A obtained when viewed in plan from the foil surface side.

  By controlling the current density and plating time of the surface treatment during the surface treatment such as the formation of roughened particles, the surface state of the copper foil after the surface treatment and the form and formation density of the roughened particles are determined. Rz, glossiness, and area ratio B / A of the copper foil surface can be controlled.

  The surface-treated copper foil of the present invention can be bonded to a resin substrate from the surface-treated surface side to produce a laminate. The resin substrate is not particularly limited as long as it has characteristics applicable to a printed wiring board or the like. For example, a paper base phenol resin, a paper base epoxy resin, a synthetic fiber cloth base epoxy resin for rigid PWB Glass cloth / paper composite base material epoxy resin, glass cloth / glass nonwoven fabric composite base material epoxy resin and glass cloth base material epoxy resin, etc. are used, polyester film, polyimide film, liquid crystal polymer (LCP) film, Teflon for FPC (Registered trademark) film or the like can be used.

In the case of the rigid PWB, a prepreg is prepared by impregnating a base material such as a glass cloth with a resin and curing the resin to a semi-cured state. It can be carried out by superposing a copper foil on the prepreg from the opposite surface of the coating layer and heating and pressing. In the case of FPC, it is laminated on a copper foil under high temperature and high pressure without using an adhesive on a substrate such as a polyimide film, or a polyimide precursor is applied, dried, cured, etc. A laminated board can be manufactured by performing.
The thickness of the polyimide base resin is not particularly limited, but generally 25 μm or 50 μm can be mentioned.

  The laminate of the present invention can be used for various printed wiring boards (PWB) and is not particularly limited. For example, from the viewpoint of the number of layers of the conductor pattern, the single-sided PWB, the double-sided PWB, and the multilayer PWB (3 It is applicable to rigid PWB, flexible PWB (FPC), and rigid flex PWB from the viewpoint of the type of insulating substrate material.

(Laminated board and printed wiring board positioning method using the same)
A method for positioning the laminate of the surface-treated copper foil and the resin substrate of the present invention will be described. First, a laminate of a surface-treated copper foil and a resin substrate is prepared. As a specific example of the laminate of the surface-treated copper foil and the resin substrate according to the present invention, at least one of a main substrate, an attached circuit substrate, and a resin substrate such as polyimide used for electrically connecting them. In an electronic device composed of a flexible printed circuit board with copper wiring formed on the surface, a laminated board manufactured by accurately positioning the flexible printed circuit board and crimping it to the wiring ends of the main circuit board and the attached circuit board Is mentioned. That is, in this case, the laminate is a laminate in which the wiring end portions of the flexible printed circuit board and the main body substrate are bonded together by pressure bonding, or the wiring edge portions of the flexible printed circuit board and the circuit board are bonded together by pressure bonding. Laminated board. The laminated board has a mark formed of a part of the copper wiring and a separate material. The position of the mark is not particularly limited as long as it can be photographed by photographing means such as a CCD camera through the resin constituting the laminated plate.

  In the laminated plate thus prepared, when the above-described mark is photographed by the photographing means through the resin, the position of the mark can be detected satisfactorily. And the position of the said mark can be detected in this way, and based on the position of the said detected mark, the positioning of the laminated board of surface-treated copper foil and a resin substrate can be performed favorably. Similarly, when a printed wiring board is used as the laminated board, the photographing means can detect the position of the mark well by such a positioning method, and the printed wiring board can be positioned more accurately.

  Therefore, when one printed wiring board and another printed wiring board are connected, it is considered that the connection failure is reduced and the yield is improved. In addition, as a method of connecting one printed wiring board and another printed wiring board, connection via soldering or anisotropic conductive film (ACF), anisotropic conductive paste (Anisotropic Conductive Paste, A known connection method such as connection via ACP) or connection via a conductive adhesive can be used. In the present invention, the “printed wiring board” includes a printed wiring board, a printed circuit board, and a printed board on which components are mounted. Also, it is possible to manufacture a printed wiring board in which two or more printed wiring boards are connected by connecting two or more printed wiring boards according to the present invention, and at least one printed wiring board according to the present invention. One printed wiring board of the present invention or a printed wiring board not corresponding to the printed wiring board of the present invention can be connected, and an electronic apparatus can be manufactured using such a printed wiring board. In the present invention, “copper circuit” includes copper wiring. Furthermore, the printed wiring board of the present invention may be connected to a component to produce a printed wiring board. Further, at least one printed wiring board of the present invention is connected to another printed wiring board of the present invention or a printed wiring board not corresponding to the printed wiring board of the present invention. A printed wiring board in which two or more printed wiring boards are connected may be manufactured by connecting two or more printed wiring boards and components. Here, as “components”, connectors, LCDs (Liquid Crystal Display), electronic components such as glass substrates used in LCDs, ICs (Integrated Circuits), LSIs (Large scale integrated circuits), VLSIs (Very Large scale circuits). ), Electronic components including semiconductor integrated circuits such as ULSI (Ultra-Large Scale Integrated Circuit) (for example, IC chip, LSI chip, VLSI chip, ULSI chip), components for shielding electronic circuits, and covers on printed wiring boards, etc. Examples of the parts necessary to fix the are included.

The positioning method according to the embodiment of the present invention may include a step of moving a laminated board (including a laminated board of copper foil and a resin substrate and a printed wiring board). In the moving process, for example, it may be moved by a conveyor such as a belt conveyor or a chain conveyor, may be moved by a moving device provided with an arm mechanism, or may be moved by floating a laminated plate using gas. It may be moved by a moving means, a moving device or moving means (including a roller or a bearing) that moves a laminated plate by rotating an object such as a substantially cylindrical shape, a moving device or moving means that uses hydraulic pressure as a power source, Moving devices and moving means powered by air pressure, moving devices and moving means powered by motors, gantry moving linear guide stages, gantry moving air guide stages, stacked linear guide stages, linear motor drive stages, etc. It may be moved by a moving device or moving means having a stage. Moreover, you may perform the movement process by a well-known moving means.
The positioning method according to the embodiment of the present invention may be used for a surface mounter or a chip mounter.
Moreover, the printed wiring board which has the circuit provided on the resin board and the said resin board may be sufficient as the laminated board of the surface treatment copper foil and the resin board which are positioned in this invention. In that case, the mark may be the circuit.

In the present invention, “positioning” includes “detecting the position of a mark or an object”. In the present invention, “alignment” includes “after detecting the position of a mark or object, moving the mark or object to a predetermined position based on the detected position”.
In the printed wiring board, the circuit on the printed wiring board is used as a mark instead of the mark on the printed material, and the Sv value can be measured by photographing the circuit through a resin with a CCD camera. Also, for copper-clad laminates, after copper was etched into a line shape, the lined copper was used as a mark instead of a printed mark, and the lined copper was photographed with a CCD camera through the resin. Thus, the value of Sv can be measured.

  As Examples 1-8 and Comparative Examples 1-5, each copper foil was prepared, and the plating process was performed on the conditions of Table 2 as surface treatment on one surface. Moreover, the thing which does not perform a roughening process was also prepared. “No” in the “Roughening treatment” column of “Surface treatment” in Table 2 indicates that the surface treatment is not a roughening treatment, and “Yes” indicates that the surface treatment is a roughening treatment.

In addition, the rolled copper foil ("Tough pitch copper" in the "Kind" column of Table 1 indicates that it is a rolled copper foil) was produced as follows. After manufacturing a predetermined copper ingot and performing hot rolling, annealing and cold rolling of a 300-800 degreeC continuous annealing line were repeated, and the rolled sheet of 1-2 mm thickness was obtained. This rolled plate was annealed and recrystallized in a continuous annealing line at 300 to 800 ° C., and finally cold-rolled to the thickness shown in Table 1 to obtain a copper foil. “Tough pitch copper” in Table 1 indicates tough pitch copper standardized in JIS H3100 C1100.
Table 1 shows the points of the copper foil preparation process before the surface treatment. “High gloss rolling” means that the final cold rolling (cold rolling after the final recrystallization annealing) was performed at the value of the oil film equivalent. In addition, about Example 1, 2, the copper foil whose thickness of copper foil is 6 micrometers, 12 micrometers, and 35 micrometers was also manufactured.

Various evaluation was performed as follows about each sample of the Example and comparative example which were produced as mentioned above.
(1) Measurement of surface roughness (Rz);
About the copper foil after the surface treatment of each Example and Comparative Example, the surface roughness of the ten-point average roughness was measured in accordance with JIS B0601-1994 using a contact roughness meter Surfcoder SE-3C manufactured by Kosaka Laboratory Ltd. The surface was measured. Measurement standard length 0.8mm, evaluation length 4mm, cut-off value 0.25mm, feed rate 0.1mm / sec. The measurement position was changed 10 times in the direction (TD), and the value of 10 measurements was obtained.
In addition, the surface roughness (Rz) was calculated | required similarly about the copper foil before surface treatment.

(2) Measurement of the ratio C / A between the surface area A of the copper foil surface and the convex volume C;
About the surface treatment surface of the copper foil after the surface treatment of each Example and Comparative Example, the surface area A and the convex volume C obtained when viewed in a plane with an Olympus laser microscope OLS4000 were measured, and the ratio C / A was calculated. The value was determined from the conditions of an evaluation area of 647 μm × 646 μm and a cutoff value of zero. In addition, the measurement environmental temperature of the surface area A and convex part volume C obtained when it planarly views with a laser microscope was 23-25 degreeC.

(3) Area ratio of copper foil surface (B / A);
About the surface treatment surface of the copper foil after surface treatment of each Example and a comparative example, the measuring method by a laser microscope was used for the surface area of the copper foil surface. About the copper foil after the surface treatment of each Example and Comparative Example, an area equivalent to 647 μm × 646 μm at a magnification of 20 times of the treated surface using a Olympus laser microscope OLS4000 (surface area obtained when viewed in plan) A (actual data) Then, the three-dimensional surface area B at 417,953 μm ² ) was measured, and the calculation was performed by the method of three-dimensional surface area B ÷ two-dimensional surface area A = area ratio (B / A). In addition, the measurement environmental temperature of the three-dimensional surface area B with a laser microscope was 23-25 degreeC.

(4) Glossiness;
Incidence in a direction perpendicular to the rolling direction or the traveling direction of the electrolytic copper foil in the electrolytic copper foil manufacturing apparatus using a gloss meter PG-1 manufactured by Nippon Denshoku Industries Co., Ltd. conforming to JIS Z8741 The glossiness at an angle of 60 degrees was measured for the copper foil before the surface treatment.

(5) Inclination of brightness curve The copper foil was bonded to both sides of a polyimide film (50 μm Kaneka thickness, PIXIO for two-layer copper-clad laminate), and the copper foil was removed by etching (ferric chloride aqueous solution). A sample film was prepared. Subsequently, a printed material on which a line-shaped black mark is printed is laid under the sample film, the printed material is photographed with a CCD camera through the sample film, and the observed line-shaped mark is observed on the image obtained by photographing. In the observation point-lightness graph created by measuring the lightness at each observation point along the direction perpendicular to the direction of extension, the inclination (angle) of the lightness curve that occurs from the end of the mark to the part where the mark is not drawn It was measured. FIG. 3 is a schematic diagram showing the configuration of the photographing apparatus used at this time and the method of measuring the inclination of the brightness curve.
Further, ΔB, t1, t2, and Sv were measured by the following photographing apparatus as shown in FIG. One pixel on the horizontal axis corresponds to a length of 10 μm.
The photographing device has a CCD camera, a stage (white) on which a polyimide substrate is placed with a marked paper underneath, an illumination power source that irradiates light onto the photographing portion of the polyimide substrate, and a paper with a mark to be photographed. A transporter (not shown) for transporting the evaluation polyimide substrate placed below onto the stage is provided. The main specifications of the camera are as follows:
・ Photographing device: Sheet inspection device Mujken manufactured by Nireco Corporation
CCD camera: 8192 pixels (160 MHz), 1024 gradation digital (10 bits)
・ Power supply for lighting: High-frequency lighting power supply (power supply unit x 2)
・ Lighting: Fluorescent lamp (30W)
For the lightness shown in FIG. 3, 0 means “black”, lightness 255 means “white”, and the gray level from “black” to “white” (black and white shading, gray scale) Is divided into 256 gradations for display.

(6) Visibility (resin transparency);
The copper foil was bonded to both sides of a polyimide film (Kaneka thickness 50 μm), and the copper foil was removed by etching (ferric chloride aqueous solution) to prepare a sample film. A printed material (black circle with a diameter of 6 cm) was attached to one surface of the obtained resin layer, and the visibility of the printed material was judged from the opposite surface through the resin layer. “◎” indicates that the outline of the black circle of the printed material is clear when the length is 90% or more of the circumference, and “Clear” indicates that the outline of the black circle is clear when the length is 80% or more and less than 90% of the circumference. “O” (passed above), a black circle with a clear outline of 0 to less than 80% of the circumference and a broken outline were evaluated as “x” (failed).

(7) Peel strength (adhesive strength);
Based on IPC-TM-650, the normal peel strength was measured with a tensile tester Autograph 100, and a normal peel strength of 0.7 N / mm or more could be used for laminated substrates. In addition, the sample which bonded the surface treatment surface of the surface-treated copper foil which concerns on the Example and comparative example of this invention and the polyimide film with a thickness of 50 micrometers made from Kaneka was used for the measurement of this peel strength. At the time of measurement, the polyimide film is affixed to a hard substrate (stainless steel plate or synthetic resin plate (which does not have to be deformed during peel strength measurement)) with double-sided tape or with an instantaneous adhesive. Fixed by attaching. The unit of the peel strength value in the table is N / mm.

(8) Solder heat resistance evaluation;
Copper foil was bonded to both surfaces of a polyimide film (Kaneka thickness 50 μm). About the obtained double-sided laminated board, the test coupon based on JISC6471 was created. The prepared test coupon was exposed to high temperature and high humidity of 85 ° C. and 85% RH for 48 hours, and then floated in a solder bath at 300 ° C. to evaluate solder heat resistance. After the solder heat resistance test, at the interface between the copper foil roughening surface and the polyimide resin adhesion surface, the area where the interface discolored due to blistering in an area of 5% or more of the copper foil area in the test coupon is x (failed), area When the color change was less than 5%, the case was evaluated as ◯, and the case where no color change occurred was evaluated as ◎.

(9) Yield Copper foil was bonded to both sides of a polyimide film (Kaneka thickness 50 μm), and the copper foil was etched (ferric chloride aqueous solution) to create an FPC with a circuit width of L / S 30 μm / 30 μm. . After that, an attempt was made to detect a 20 μm × 20 μm square mark with a CCD camera through polyimide. “◎” when 9 times or more out of 10 times can be detected, “◯” when 7 to 8 times can be detected, “△” when 6 times can be detected, and when 5 times or less can be detected. Is “×”.
In the printed wiring board or the copper-clad laminate, the above-mentioned (1) surface roughness (Rz) and (2) the surface area of the copper foil surface are obtained by dissolving and removing the resin. Measurement of ratio C / A of A and convex part volume C, (3) Area ratio (A / B) of the copper foil surface can be measured.
Tables 1 and 2 show the conditions and evaluation of the above tests.

(Evaluation results)
In Examples 1 to 8, the ratio C / A between the surface area A obtained when the surface is viewed in plan and the convex volume C of the surface is in the range of 2.11 to 23.91, and Sv is The visibility, peel strength, solder heat resistance evaluation, and yield were good. In addition, the copper foils manufactured for Examples 1 and 2 and having thicknesses of 6 μm, 12 μm, and 35 μm had the same results as in Examples 1 and 2 having a thickness of 18 μm. That is, the ratio of the surface area A obtained when the surfaces of the copper foils manufactured for Examples 1 and 2 having a thickness of 6 μm, 12 μm, and 35 μm in plan view to the convex volume C of the surface C / A was in the range of 2.11 to 23.91, Sv was 3.5 or more, and visibility, peel strength, solder heat resistance evaluation and yield were good.
In Comparative Example 1, the ratio C / A between the surface area A obtained when the surface was viewed in plan and the convex volume C of the surface was less than 2.11, and the peel strength and solder heat resistance were poor. .
In Comparative Examples 2, 3 and 5, the ratio C / A between the surface area A obtained when the surface is viewed in plan and the convex volume C of the surface exceeds 23.91, and Sv is less than 3.5. Yes, visibility was poor. In Comparative Example 4, Sv was less than 3.5, and the visibility was poor.
FIG. 4 shows (a) Comparative Example 1, (b) Example 1, (c) Example 2, (d) Example 3, (e) Example 4, and (f) in the Rz evaluation. The SEM observation photograph on the copper foil surface of Example 5, (g) Example 6, (h) Example 7, (i) Example 8, (j) Comparative Example 2, (k) Comparative Example 3 is shown, respectively.

Claims (16)

Surface treatment is performed on at least one surface, and a surface area A obtained when the surface on which the surface treatment is performed is viewed in plan and a convex volume C on the surface on which the surface treatment is performed A surface-treated copper foil having a ratio C / A of 2.11 to 23.91,
After bonding the copper foil to both sides of the polyimide resin substrate from the surface side where the surface treatment is performed, the copper foil on both sides is removed by etching,
When a printed matter on which a line-shaped mark is printed is laid under the exposed polyimide substrate, and the printed matter is photographed with a CCD camera through the polyimide substrate,
For the image obtained by the photographing, an observation point-brightness graph prepared by measuring the brightness of each observation point along the direction perpendicular to the direction in which the observed line-shaped mark extends,
The difference between the top average value Bt and the bottom average value Bb of the brightness curve generated from the end of the mark to the part where the mark is not drawn is ΔB (ΔB = Bt−Bb). The value indicating the position of the intersection closest to the line-shaped mark among the intersections of the curve and Bt is t1, and the brightness is within a depth range from the intersection of the brightness curve and Bt to 0.1 ΔB with reference to Bt. Surface where Sv defined by the following equation (1) is 3.5 or more when the value indicating the position of the intersection closest to the line-shaped mark among the intersections of the curve and 0.1 ΔB is t2. Treated copper foil.
Sv = (ΔB × 0.1) / (t1-t2) (1)   The surface-treated copper foil according to claim 1, wherein the ratio C / A is 2.95 to 21.42.   The surface-treated copper foil of Claim 1 or 2 from which Sv defined by (1) Formula in the said brightness curve becomes 3.9 or more.   The surface-treated copper foil in any one of Claims 1-3 from which Sv defined by (1) Formula in the said brightness curve becomes 5.0 or more.   The surface-treated copper foil according to any one of claims 1 to 4, wherein a ten-point average roughness Rz of TD on the surface is 0.20 to 0.64 µm.   The surface-treated copper foil according to claim 5, wherein the ten-point average roughness Rz of the surface TD is 0.40 to 0.62 µm.   The ratio B / A between the three-dimensional surface area B of the surface and the two-dimensional surface area (surface area obtained when the surface is viewed in plan) A is 1.0 to 1.7. The surface-treated copper foil of description.   The surface-treated copper foil according to claim 7, wherein the B / A is 1.0 to 1.6.   The laminated board comprised by laminating | stacking the surface treatment copper foil and resin substrate in any one of Claims 1-8.   The printed wiring board using the surface-treated copper foil in any one of Claims 1-8.   The electronic device using the printed wiring board of Claim 10.   A method for manufacturing a printed wiring board in which two or more printed wiring boards are connected by connecting two or more printed wiring boards according to claim 10.   It includes at least a step of connecting at least one printed wiring board according to claim 10 to another printed wiring board according to claim 10 or a printed wiring board not corresponding to the printed wiring board according to claim 10. A method of manufacturing a printed wiring board in which two or more printed wiring boards are connected.   An electronic device using one or more printed wiring boards to which at least one printed wiring board according to claim 12 is connected.   A method for producing a printed wiring board, comprising at least a step of connecting the printed wiring board according to claim 10 and a component. Connecting at least one printed wiring board according to claim 10 to another printed wiring board according to claim 10 or a printed wiring board not corresponding to the printed wiring board according to claim 10, and
A printed wiring board having two or more printed wiring boards connected, comprising at least a step of connecting a printed wiring board according to claim 10 or two or more printed wiring boards according to claim 13 and a component. A method of manufacturing a wiring board.