JP2011014654A - Copper foil for printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide copper foil for printed wiring boards that is satisfactory in both the adhesion to an insulating substrate and etching performance, and that is low in the manufacturing cost.SOLUTION: The copper foil for printed wiring boards includes a copper foil base material and a coating layer for coating at least one portion of the surface of the copper foil base material. The coating layer is composed of an Ni-Mn alloy layer containing Ni and Mn and a Cr layer, stacked successively from the surface of the copper foil base material, the Cr layer and the Ni-Mn alloy layer have Cr, and Ni and Mn by coating amounts of 15-210 μg/dmat 20-440 μg/dm, respectively, and the Ni-Mn alloy layer has Mn by 15-75 wt.%.

Description

  The present invention relates to a copper foil for a printed wiring board, and more particularly to a copper foil for a flexible printed wiring board.

  Printed wiring boards have made great progress over the last half century and are now used in almost all electronic devices. In recent years, with the increasing needs for miniaturization and higher performance of electronic devices, higher density mounting of components and higher frequency of signals have progressed, and conductor patterns have become finer (fine pitch) and higher frequency than printed circuit boards. Response is required.

  In general, a printed wiring board is manufactured through a process of forming a copper-clad laminate by bonding an insulating substrate to a copper foil and then forming a conductor pattern on the surface of the copper foil by etching. Therefore, the copper foil for printed wiring boards is required to have adhesiveness and etching properties with an insulating substrate.

  As a technique for improving the adhesion to an insulating substrate, a surface treatment for forming irregularities on a copper foil surface called a roughening treatment is generally performed. For example, by using a copper sulfate acidic plating bath on the M surface (rough surface) of the electrolytic copper foil, a large number of coppers are electrodeposited in a dendritic or small spherical shape to form fine irregularities, and the adhesion is improved by the anchoring effect. There is. After the roughening treatment, a chromate treatment, a treatment with a silane coupling agent, or the like is generally performed in order to further improve the adhesive properties.

  A method of forming a metal layer or alloy layer of tin, chromium, copper, iron, cobalt, zinc, nickel or the like on the surface of the copper foil is also known.

  However, the method of improving adhesiveness by roughening treatment is disadvantageous for fine line formation. That is, when the conductor interval is narrowed by fine pitch, the roughened portion may remain on the insulating substrate after the circuit is formed by etching, which may cause insulation deterioration. In order to prevent this, if an attempt is made to etch the entire roughened surface, a long etching time is required, and a predetermined wiring width cannot be maintained.

  In the method of providing, for example, a Ni layer or a Ni—Cr alloy layer on the surface of the copper foil, there is much room for improvement in the basic characteristic of adhesion to the insulating substrate. For example, a method of providing a Cr layer on a copper foil surface provides relatively high adhesiveness, but is poor in etching property, and after etching for forming a conductor pattern, Cr remains on the insulating substrate surface. "Is likely to occur.

  Therefore, in recent years, a first metal layer is formed on the surface of the copper foil, and a Cr layer having good adhesiveness with an insulating substrate is formed on the first metal layer as the second metal layer with good etching properties. Research and development have been conducted on a technique for simultaneously obtaining good adhesion to an insulating substrate and good etching property by forming the thin film to such a degree.

As such a technique, for example, in Patent Document 1, in a surface-treated copper foil for a polyimide-based flexible copper-clad laminate, a Ni layer containing Ni in an amount of 0.03 to 3.0 mg / dm ² or / and Ni By providing a Cr layer or / and a Cr alloy layer containing 0.03 to 1.0 mg / dm ^{2 as} a Cr treatment on the alloy layer as a surface treatment layer, a high peel strength can be obtained between the polyimide resin layer and the alloy layer. It is described that a copper foil for a polyimide-based flexible copper-clad laminate having excellent insulation reliability, etching characteristics when forming a wiring pattern, and bending characteristics can be obtained.

JP 2006-222185 A

  However, as described in Patent Document 1, those in which a large amount of Ni is present in the coating layer on the surface of the copper foil have relatively high adhesion to the insulating substrate and etching properties, but there is still room for improvement. Yes. In addition, when a coating layer containing a large amount of Ni is formed by sputtering, a magnetic target is used. However, the magnetic target has a problem that it is disadvantageous in terms of cost because of its poor use efficiency and short life.

  Then, this invention makes it a subject to provide the copper foil for printed wiring boards which is excellent in both the adhesiveness with an insulated substrate, and etching property, and whose manufacturing cost is favorable. Moreover, this invention makes it another subject to provide the manufacturing method of such copper foil for printed wiring boards.

Conventionally, it is understood that by providing a Ni layer and a Cr layer with an extremely thin thickness in order on the surface of a copper foil base material, it is possible to obtain good etching properties at the same time while obtaining good adhesion with an insulating substrate. was there. On the other hand, as a result of intensive studies to provide a copper foil for a printed wiring board having high adhesiveness and etching properties with an insulating substrate, the present inventors have sequentially formed a Ni-Mn alloy layer and a copper foil base surface. It has been found that when a Cr layer is uniformly provided with an ultrathin thickness on the order of nanometers, a copper foil coating layer having better adhesion to an insulating substrate and excellent etching properties can be obtained.
In that case, the heat resistance that can withstand long-term use, and the surface-treated metal reacts with corrosive gas and moisture during the manufacturing process from copper foil surface treatment to copper clad laminate formation. It has also been found that the corrosion resistance for preventing the quality from deteriorating is improved. Here, although etching property and corrosion resistance are performances which are contrary to each other, according to the present invention, it has also been found that the balance between the two becomes good.
Furthermore, it discovered that the use efficiency of the sputtering target at the time of manufacture improved, and manufacturing cost could be reduced by adjusting the component of each metal element in a Ni-Mn alloy layer.

The present invention completed on the basis of the above knowledge is, in one aspect, a copper foil for a printed wiring board provided with a copper foil substrate and a coating layer covering at least a part of the surface of the copper foil substrate, The coating layer is composed of a Ni—Mn alloy layer containing Ni and Mn and a Cr layer, which are sequentially laminated from the surface of the copper foil base, and the Cr layer has a Cr content of 15 to 210 μg / dm ² , and the Ni— The total amount of Ni and Mn is present in the Mn alloy layer at a coating amount of ²⁰ to 440 μg / dm ² , and 15 to 75% by weight of Mn is present in the Ni—Mn alloy layer.

In one embodiment of the copper foil for printed wiring boards according to the present invention, the Cr layer has a Cr of 18 to 100 μg / dm ² , and the Ni—Mn alloy layer has a total of Ni and Mn of 85 to 260 μg / dm. Each is present at a coverage of ² .

In another embodiment of the copper foil for printed wiring boards according to the present invention, Ni is present in the Ni-Mn alloy layer at a coverage of Ni of 15 to 430 μg / dm ² and Mn of 10 to 220 μg / dm ² , respectively. To do.

  In yet another embodiment of the copper foil for printed wiring board according to the present invention, the maximum thickness is 0.5 to 8.0 nm and the minimum thickness is the maximum thickness when the cross section of the coating layer is observed with a transmission electron microscope. 80% or more.

  In yet another embodiment of the copper foil for printed wiring board according to the present invention, the atomic concentration (%) of chromium in the depth direction (x: unit nm) obtained from the depth direction analysis from the surface by XPS. F (x), oxygen atomic concentration (%) as g (x), copper atomic concentration (%) as h (x), nickel atomic concentration (%) as i (x), manganese When j (x) is the atomic concentration (%) of carbon and k (x) is the atomic concentration (%) of carbon, 区間 h (x) dx / (∫f (x) in the interval [0, 1.0] dx + ∫g (x) dx + ∫h (x) dx + ∫i (x) dx + ∫j (x) dx + ∫k (x) dx) is 1.0% or less.

In yet another embodiment of the copper foil for printed wiring board according to the present invention, the depth direction (x: unit nm) of metal chromium and oxide chromium obtained from the depth direction analysis from the surface by XPS. If the atomic concentration (%) is f ₁ (x) and f ₂ (x), respectively, 0 ≦ ∫f ₁ (x) dx / ∫f ₂ (x) dx ≦ 1 in the interval [0, 1.0] 0.0 and 0.1 ≦ ∫f ₁ (x) dx / ∫f ₂ (x) dx ≦ 1.0 in the interval [1.0, 2.5].

In yet another embodiment of the copper foil for printed wiring boards according to the present invention, when a heat treatment equivalent to polyimide curing is performed, the surface of the coating layer is analyzed and obtained from a depth direction analysis from the surface by XPS. The atomic concentration (%) of chromium in the depth direction (x: unit nm) is f (x), the atomic concentration (%) of oxygen is g (x), and the atomic concentration (%) of copper is h (x ), The atomic concentration (%) of nickel is i (x), the atomic concentration (%) of manganese is j (x), and the atomic concentration (%) of carbon is k (x), the interval [0, 1 .0], ∫h (x) dx / (∫f (x) dx + ∫g (x) dx + ∫h (x) dx + ∫i (x) dx + ∫j (x) dx + ∫k (x) dx) is 5.0% or less.
Here, “heat treatment equivalent to polyimide curing” refers to heat treatment to the extent that the polyimide adhered to the coating layer is cured, and specifically represents heat treatment at a temperature of about 350 ° C. for about 30 minutes to several hours. .

In yet another embodiment of the copper foil for printed wiring boards according to the present invention, when a heat treatment equivalent to polyimide curing is performed, the surface of the coating layer is analyzed and obtained from a depth direction analysis from the surface by XPS. Assuming that atomic concentrations (%) in the depth direction (x: unit nm) of metallic chromium and oxide chromium are f ₁ (x) and f ₂ (x), respectively, 0 in the interval [0, 1.0] 1 ≦ ∫f ₁ (x) dx / ∫f ₂ (x) dx ≦ 1.0 is satisfied, and in the interval [1.0, 2.5], 0.1 ≦ ［f ₁ (x) dx / ∫ f ₂ (x) dx ≦ 1.0 is satisfied.

  In yet another embodiment of the copper foil for printed wiring board according to the present invention, the copper foil is subjected to a heat treatment equivalent to polyimide curing, and when the surface of the coating layer is analyzed, the depth from the surface by XPS The atomic concentration (%) of chromium in the depth direction (x: unit nm) obtained from the direction analysis is f (x), the atomic concentration (%) of oxygen is g (x), and the atomic concentration of copper (%) ) Is h (x), the atomic concentration (%) of nickel is i (x), the atomic concentration (%) of manganese is j (x), and the atomic concentration (%) of carbon is k (x), In the interval [0, 1.0], ∫h (x) dx / (∫f (x) dx + ∫g (x) dx + ∫h (x) dx + ∫i (x) dx + ∫j (x ) dx + ∫k (x) dx) is 5.0% or less.

In yet another embodiment of the copper foil for printed wiring board according to the present invention, the copper foil is subjected to a heat treatment equivalent to polyimide curing, and when the surface of the coating layer is analyzed, the depth from the surface by XPS Assuming that atomic concentrations (%) in the depth direction (x: unit nm) of the chromium metal oxide and the chromium oxide obtained from the direction analysis are f ₁ (x) and f ₂ (x), respectively, the intervals [0, 1.. 0], 0.1 ≦ ∫f ₁ (x) dx / ∫f ₂ (x) dx ≦ 1.0 is satisfied, and in the interval [1.0, 2.5], 0.1 ≦ ∫f ₁ ( x) dx / ∫f ₂ (x) dx ≦ 1.0 is satisfied.

  In yet another embodiment of the copper foil for printed wiring boards according to the present invention, a polyamic acid solution, which is a polyimide precursor, is applied on the coating layer so as to have a dry body of 25 μm, and is 120 ° C. in an air dryer. A polyimide is formed on the coating layer through a process of imidizing in 30 minutes and a process of imidizing in 350 ° C for 30 minutes in a high-temperature heating furnace in which a nitrogen flow rate is set to 10 L / min. When the polyimide film is peeled from the coating layer according to the 90 ° peeling method (JIS C 6471 8.1) after being left in a high temperature environment in an air atmosphere for 168 hours, the cross section of the coating layer is observed with a transmission electron microscope. The maximum thickness is 0.5 to 8.0 nm, and the minimum thickness is 70% or more of the maximum thickness.

  In yet another embodiment of the copper foil for printed wiring board according to the present invention, the copper foil for printed wiring board formed on the insulating substrate via the coating layer, after peeling the insulating substrate from the coating layer When analyzing the surface of the coating layer, the atomic concentration (%) of chromium obtained from the depth analysis from the surface by XPS is f (x), the atomic concentration (%) of oxygen is g (x), The surface layer where the atomic concentration (%) of copper is h (x), the atomic concentration (%) of nickel is i (x), the atomic concentration (%) of manganese is j (x), and the chromium concentration is maximum. If the distance from F is F, in the interval [0, F], ∫h (x) dx / (∫f (x) dx + ∫g (x) dx + ∫h (x) dx + ∫i (x) dx + ∫j (x) dx) is 5.0% or less.

In yet another embodiment of the copper foil for printed wiring board according to the present invention, the copper foil for printed wiring board formed on the insulating substrate via the coating layer, after peeling the insulating substrate from the coating layer When analyzing the surface of the coating layer, the atomic concentration (%) of chromium obtained from the depth direction analysis by XPS is defined as f (x), and the atomic concentration (%) of metallic chromium is defined as f ₁ (x). Where the atomic concentration (%) of chromium oxide is f ₂ (x), and the distances from the surface layer where the chromium and nickel concentrations are maximum are F and I, respectively, in the interval [0, F], 0. 1 ≦ ∫f ₁ (x) dx / ∫f ₂ (x) dx ≦ 1.0, and in the section [F, I], 0.1 ≦ ∫f ₁ (x) dx / ∫f ₂ (x) dx ≦ 1.0.

  In yet another embodiment of the copper foil for printed wiring board according to the present invention, the copper foil base material is a rolled copper foil.

  In another embodiment of the copper foil for printed wiring boards according to the present invention, the printed wiring board is a flexible printed wiring board.

  In another aspect of the present invention, at least a part of the surface of the copper foil base material is formed by sputtering to form a Ni-Mn alloy layer having a thickness of 0.3 to 5.0 nm and a Cr layer having a thickness of 0.2 to 3.0 nm. It is a manufacturing method of the copper foil for printed wiring boards including covering sequentially.

  In still another aspect, the present invention is a copper clad laminate including the copper foil according to the present invention.

  In one embodiment of the copper clad laminate according to the present invention, the copper foil has a structure bonded to polyimide.

  In yet another aspect, the present invention is a printed wiring board made of the copper clad laminate according to the present invention.

  A copper foil for a printed wiring board is obtained that is excellent in both adhesion to an insulating substrate and etching property, suitable for fine pitch, and has good manufacturing cost.

Example No. 9 is a TEM photograph (cross section) of No. 9 copper foil (sputter rising). Example No. 9 is a TEM photograph (cross section) of No. 9 copper foil (after heat treatment equivalent to polyimide varnish curing). Example No. It is a depth profile by XPS of No. 9 copper foil (sputtering rise). Example No. 9 is a depth profile by XPS of No. 9 copper foil (after heat treatment equivalent to polyimide varnish curing). Example No. It is a depth profile by XPS when the chromium of No. 9 copper foil (sputtering rise) is isolate | separated into metal chromium and oxide chromium. Example No. It is a depth profile by XPS when the chromium of No. 9 copper foil (after heat processing equivalent to polyimide varnish hardening) is isolate | separated into metal chromium and oxide chromium.

(Copper foil base material)
Although there is no restriction | limiting in particular in the form of the copper foil base material which can be used for this invention, Typically, it can use with the form of rolled copper foil or electrolytic copper foil. In general, the electrolytic copper foil is produced by electrolytic deposition of copper from a copper sulfate plating bath onto a drum of titanium or stainless steel, and the rolled copper foil is produced by repeating plastic working and heat treatment with a rolling roll. Rolled copper foil is often used for applications that require flexibility.
In addition to high-purity copper such as tough pitch copper and oxygen-free copper, which are usually used as conductor patterns for printed wiring boards, for example, Sn-containing copper, Ag-containing copper, Cr, Zr or Mg are added as the copper foil base material It is also possible to use a copper alloy such as a copper alloy, a Corson copper alloy to which Ni, Si and the like are added. In addition, when the term “copper foil” is used alone in this specification, a copper alloy foil is also included.

  There is no restriction | limiting in particular also about the thickness of the copper foil base material which can be used for this invention, What is necessary is just to adjust to the thickness suitable for printed wiring boards suitably. For example, it can be set to about 5 to 100 μm. However, for the purpose of forming a fine pattern, it is 30 μm or less, preferably 20 μm or less, and typically about 6 to 20 μm.

  The copper foil substrate used in the present invention is preferably not roughened. Conventionally, the surface roughening treatment is performed by applying irregularities of the order of μm on the surface by special plating, and the adhesion to the resin is given by the physical anchor effect. On the other hand, fine pitch and high frequency electrical characteristics are considered to be smooth foils, and roughened foils work in a disadvantageous direction. Further, since the roughening process is omitted, there is an effect of improving economy and productivity. Therefore, the foil used in the present invention is a foil that is not specially roughened.

(Coating layer)
At least a part of the surface of the copper foil base material is sequentially coated with a Ni—Mn alloy layer and a Cr layer. The Ni—Mn alloy layer and the Cr layer constitute a coating layer. Although there is no restriction | limiting in particular in the location to coat | cover, It is common to set it as the location where adhesion | attachment with an insulated substrate is planned. Adhesion with the insulating substrate is improved by the presence of the coating layer. In general, the adhesive force between a copper foil and an insulating substrate tends to decrease when placed in a high temperature environment, which is considered to be caused by thermal diffusion of copper to the surface and reaction with the insulating substrate. In this invention, the thermal diffusion of copper can be prevented by previously providing the Ni-Mn alloy layer excellent in copper diffusion prevention on the copper foil base material. Further, the adhesion with the insulating substrate can be further improved by providing the Cr layer, which has better adhesion with the insulating substrate than the Ni-Mn alloy layer, on the Ni-Mn alloy layer. Since the thickness of the Cr layer can be reduced by virtue of the presence of the Ni—Mn alloy layer, the adverse effect on the etching property can be reduced. In addition, the adhesiveness referred to in the present invention is the adhesiveness after being placed under high temperature (heat resistance) and the adhesiveness after being placed under corrosive gas or high humidity (in addition to the usual adhesiveness) Corrosion resistance and moisture resistance).

  In the copper foil for printed wiring boards according to the present invention, the coating layer is extremely thin and has a uniform thickness. The reason why the adhesiveness with the insulating substrate has been improved by such a configuration is not clear, but the Cr single layer coating that is extremely excellent in adhesiveness with the resin as the outermost surface on the Ni-Mn alloy coating This is presumed to be because the single layer coating structure having high adhesiveness is maintained even after the high temperature thermal history during imidization (about 30 minutes to several hours at about 350 ° C.). Further, it is considered that the etching property is improved by making the coating layer extremely thin and reducing the amount of Cr used as a two-layer structure of a Ni—Mn alloy and Cr.

  Specifically, the coating layer according to the present invention has the following configuration.

(1) Identification of Cr, Ni—Mn alloy coating layer In the present invention, at least a part of the surface of the copper foil material is coated in the order of the Ni—Mn alloy layer and the Cr layer. These coating layers are identified by sputtering argon from the surface layer with a surface analyzer such as XPS or AES, performing chemical analysis in the depth direction, and identifying the Ni-Mn alloy layer and Cr layer by the presence of each detection peak. Can do. Moreover, the order of covering from the position of each detection peak can be confirmed.

(2) Amount of deposition On the other hand, since these Ni—Mn alloy layers and Cr layers are very thin, it is difficult to evaluate the thickness accurately with XPS and AES. For this reason, in the present invention, the thickness of the Ni—Mn alloy layer and the Cr layer is evaluated by the weight of the coated metal per unit area. In the Cr layer according to the present invention, Cr is present in a coverage of 15 to 210 μg / dm ² , and in the Ni—Mn alloy layer, the total amount of Ni and Mn is present in a coverage of ²⁰ to 440 μg / dm ² . When Cr is less than 15 μg / dm ² , sufficient peel strength cannot be obtained, and when Cr exceeds 210 μg / dm ² , the etching property tends to be significantly lowered. When the sum of Ni and Mn is less than 20 μg / dm ² , sufficient peel strength cannot be obtained, and when the sum of Ni and Mn exceeds 440 μg / dm ² , the etching property tends to be significantly reduced. The coverage of Cr is preferably 18-100 μg / dm ² , and the total coverage of Ni and Mn is preferably 85-260 μg / dm ² .

In the Ni—Mn alloy layer, Ni is present at a coating amount of 15 to 430 μg / dm ² and Mn is 10 to 220 μg / dm ² . When Ni is less than 15 μg / dm ² , sufficient heat resistance cannot be obtained, and when Ni exceeds 430 μg / dm ² , the target use efficiency decreases due to magnetism, which is disadvantageous in terms of cost. If Mn is less than 10 μg / dm ² , sufficient corrosion resistance cannot be obtained, and if Mn exceeds 220 μg / dm ² , the amount of Ni becomes too small and sufficient heat resistance cannot be obtained. The coating amount of Ni in the Ni—Mn alloy layer is preferably 75 to 220 μg / dm ² , and the coating amount of Mn is preferably 15 to 40 μg / dm ² .

  When sputtering a pure Ni layer, pure Ni is used as a target. However, this pure Ni target has strong magnetism, and sputtering by magnetron sputtering or the like is inefficient in use of the target, which is disadvantageous in terms of cost. On the other hand, the Ni-Mn alloy layer according to the present invention contains 15 to 75% by weight of Mn. If Mn in the Ni—Mn alloy layer is less than 15% by weight, the target use efficiency is poor because the magnetism is strong. When Mn in the Ni—Mn alloy layer exceeds 75% by weight, the amount of Ni decreases correspondingly, resulting in poor heat resistance. Further, the corrosion resistance increases as Mn increases until the Mn content reaches 75% by weight, but becomes constant at 75% by weight or more. Mn in the Ni—Mn alloy layer is preferably 25 to 55% by weight, more preferably 30 to 50% by weight.

(3) Observation by Transmission Electron Microscope (TEM) When the cross section of the coating layer according to the present invention is observed by a transmission electron microscope, the maximum thickness is 0.5 to 8.0 nm, preferably 0.75 to 4. The coating layer has a thickness of 5 nm and a minimum thickness of 80% or more, preferably 85% or more of the maximum thickness, and very little variation. This is because when the coating layer thickness is less than 0.5 nm, the peel strength is greatly deteriorated in the heat resistance test and the moisture resistance test, and when the thickness exceeds 8.0 nm, the etching property decreases. When the minimum value of the thickness is 80% or more of the maximum value, the thickness of the coating layer is very stable and hardly changes after the heat test. Observation by TEM makes it difficult to find a clear boundary between the Ni—Mn alloy layer and the Cr layer in the coating layer, and it looks like a single layer (see FIGS. 1 and 2). According to the study results of the present inventors, the coating layer found by TEM observation is considered to be a layer mainly composed of Cr, and the Ni—Mn alloy layer is considered to exist on the copper foil base material side. Therefore, in the present invention, the thickness of the coating layer when observed by TEM is defined as the thickness of the coating layer that looks like a single layer. However, although there may be a part where the boundary of the coating layer is unclear depending on the observation part, such a part is excluded from the thickness measurement part.

  Since the structure of the present invention suppresses the diffusion of Cu, it is considered to have a stable thickness. The copper foil of the present invention adheres to the polyimide film, and even after the resin is peeled off after undergoing a heat resistance test (standing at 168 hours in a high temperature environment at 150 ° C. in an air atmosphere), the thickness of the coating layer is almost the same. Without change, the maximum thickness is 0.5 to 8.0 nm, and even at the minimum thickness, 70% or more, preferably 75% of the maximum thickness can be maintained.

(4) Oxidation state of coating layer surface First, in order to increase the adhesive strength, it is desirable that the inner copper is not diffused on the outermost surface of the coating layer (in the range of 0 to 1.0 nm from the surface). Therefore, in the copper foil for printed wiring boards according to the present invention, when heat treatment equivalent to polyimide curing is performed, the depth direction (x: unit nm) of chromium obtained from the depth direction analysis from the surface by XPS. The atomic concentration (%) is f (x), the oxygen atomic concentration (%) is g (x), the copper atomic concentration (%) is h (x), and the nickel atomic concentration (%) is i ( x), if the atomic concentration (%) of manganese is j (x), and if the atomic concentration (%) of carbon is k (x), then in the interval [0, 1.0], に お い て h (x) dx / ( ∫f (x) dx + ∫g (x) dx + ∫h (x) dx + ∫i (x) dx + ∫j (x) dx + ∫k (x) dx) is 5.0% or less Is preferred.

In addition, on the outermost surface of the coating layer, both chromium and chromium oxide are present. However, although chromium is preferable in terms of preventing the diffusion of copper inside and ensuring adhesion, it is better. In order to obtain a good etching property, chromium oxide is preferable. Therefore, in order to achieve both the etching property and the adhesive strength, when heat treatment equivalent to polyimide curing is performed, the depth direction of metal chromium and oxide chromium obtained from the depth direction analysis from the surface by XPS (x : Unit nm) where the atomic concentration (%) is f ₁ (x) and f ₂ (x), respectively, in the interval [0, 1.0], 0.1 ≦ ∫f ₁ (x) dx / ∫f ₂ (x) dx ≦ 1.0 is preferably satisfied.

On the other hand, at a depth of 1.0 to 2.5 nm immediately below the outermost surface of the coating layer, it is desirable that the oxygen concentration is small and chromium is present in a metallic state. This is because chromium has a higher ability to prevent diffusion of copper in the metal state than the oxidized state, and can improve heat resistance. However, from the viewpoint of the cost associated with strict control of oxygen and the fact that some oxygen is present on the outermost surface and chromium is oxidized, the etching property is better. It is not realistic to disappear. Therefore, the copper foil for printed wiring boards according to the present invention has a total chromium and oxygen depth direction (x: unit) obtained from a depth direction analysis from the surface by XPS when heat treatment equivalent to polyimide curing is performed. nm) atomic concentration (%) is f (x) and g (x), respectively, in the interval [1.0, 2.5], 0.1 ≦ ∫f ₁ (x) dx / ∫f ₂ ( x) It is preferable that dx ≦ 1.0.

  In order to obtain the structure as described above, when the surface of the coating layer immediately after forming the coating layer by sputtering is analyzed, the depth direction (x: obtained from the depth direction analysis from the surface by XPS) The atomic concentration (%) of chromium (unit: nm) is f (x), the atomic concentration (%) of oxygen is g (x), the atomic concentration (%) of copper is h (x), and the atomic concentration of nickel (%) Is i (x), atomic concentration (%) of manganese is j (x), and atomic concentration (%) of carbon is k (x). (x) dx / (∫f (x) dx + ∫g (x) dx + ∫h (x) dx + ∫i (x) dx + ∫j (x) dx + ∫k (x) dx) is 1 It is preferably 0.0% or less.

Furthermore, when the surface of the coating layer immediately after forming the coating layer by sputtering was analyzed, the depth direction of metal chromium and oxide chromium (x: unit nm) obtained from the depth direction analysis from the surface by XPS If the atomic concentration (%) is f ₁ (x) and f ₂ (x), respectively, 0 ≦ ∫f ₁ (x) dx / ∫f ₂ (x) dx ≦ 1 in the interval [0, 1.0] 0.0 and satisfying 0.1 ≦ ２．５f ₁ (x) dx / ∫f ₂ (x) dx ≦ 1.0 in the interval [1.0, 2.5].

Moreover, when analyzing the surface of the coating layer after peeling the insulating substrate from the coating layer with respect to the copper foil for a printed wiring board attached to the insulating substrate via the coating layer, the depth direction from the surface by XPS The atomic concentration (%) of chromium obtained from the analysis is f (x), the atomic concentration (%) of oxygen is g (x), the atomic concentration (%) of copper is h (x), and nickel atoms If the concentration (%) is i (x), the atomic concentration (%) of manganese is j (x), and the distance from the surface layer where the chromium concentration is maximum is F, h (x) dx / (∫f (x) dx + ∫g (x) dx + ∫h (x) dx + ∫i (x) dx + ∫j (x) dx) is 5.0% or less 0.1 ≦ ∫f ₁ (x) dx / ∫f ₂ (x) dx ≦ 1.0 is desirable.

Moreover, when analyzing the surface of the coating layer after peeling the insulating substrate from the coating layer with respect to the copper foil for a printed wiring board attached to the insulating substrate via the coating layer, the depth direction from the surface by XPS The atomic concentration (%) of chromium obtained from the analysis is f (x), the atomic concentration (%) of chromium metal is f ₁ (x), and the atomic concentration (%) of chromium oxide is f ₂ (x). Assuming that the distances from the surface layer where the concentrations of chromium and nickel are maximum are F and I, respectively, 0.1 ≦ ∫f ₁ (x) dx / ∫f ₂ (x) dx in the interval [F, I] It is preferable that ≦ 1.0.

  As the above-mentioned “heat treatment equivalent to polyimide curing”, specifically, the heating time for resin curing is usually about 250 to 450 ° C. for about 10 to 60 minutes. Time.

The chromium concentration and the oxygen concentration are calculated from the peak intensities of the Cr2p orbit and O1s orbit obtained from the depth direction analysis from the surface by XPS, respectively. The distance in the depth direction (x: unit nm) is a distance calculated from the sputtering rate in terms of SiO ₂ . The chromium concentration is the total value of the oxide chromium concentration and the metal chromium concentration, and can be analyzed separately by the oxide chromium concentration and the metal chromium concentration.

(Method for producing copper foil according to the present invention)
The copper foil for printed wiring boards according to the present invention can be formed by a sputtering method. That is, at least a part of the surface of the copper foil base material is formed by sputtering to a thickness of 0.3 to 5.0 nm, preferably 0.3 to 4.0 nm, more preferably 0.5 to 3.0 nm. It can manufacture by coat | covering in order with an alloy layer and the Cr layer of thickness 0.2-3.0 nm, Preferably 0.4-2.0 nm, More preferably, 0.5-1.0 nm. When such an extremely thin film is laminated by electroplating, the thickness varies, and the peel strength tends to decrease after the heat and humidity resistance test.
The thickness here is not the thickness determined by the XPS or TEM described above, but the thickness derived from the film formation rate of sputtering. The deposition rate under a certain sputtering condition can be measured from the relationship between the sputtering time and the sputtering thickness by performing sputtering of 0.1 μm (100 nm) or more. Once the deposition rate under the sputtering conditions can be measured, the sputtering time is set according to the desired thickness. Sputtering may be performed continuously or batchwise, and the coating layer can be uniformly laminated with a thickness as defined in the present invention. Examples of the sputtering method include a direct current magnetron sputtering method.

(Manufacture of printed wiring boards)
A printed wiring board (PWB) can be manufactured according to a conventional method using the copper foil according to the present invention. Below, the example of manufacture of a printed wiring board is shown.

  First, a copper-clad laminate is manufactured by bonding a copper foil and an insulating substrate. The insulating substrate on which the copper foil is laminated is not particularly limited as long as it has characteristics applicable to a printed wiring board. For example, paper base phenolic resin, paper base epoxy resin, synthetic fiber for rigid PWB Use cloth base epoxy resin, glass cloth / paper composite base epoxy resin, glass cloth / glass non-woven composite base epoxy resin, glass cloth base epoxy resin, etc., use polyester film, polyimide film, etc. for FPC I can do things.

  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 and heating and pressing the surfaces having the prepreg and the copper foil coating layer.

  In the case of a flexible printed wiring board (FPC), a surface having a polyimide film or polyester film and a copper foil coating layer can be bonded using an epoxy or acrylic adhesive (three-layer structure). In addition, as a method without using an adhesive (two-layer structure), a polyimide varnish (polyamic acid varnish), which is a polyimide precursor, is applied to a surface having a copper foil coating layer, and imidized by heating. And a lamination method in which a thermoplastic polyimide is applied on a polyimide film, a surface having a copper foil coating layer is superimposed thereon, and heated and pressed. In the casting method, it is also effective to apply an anchor coating material such as thermoplastic polyimide in advance before applying the polyimide varnish.

  The effect of the copper foil according to the present invention is prominent when an FPC is produced by adopting a casting method. That is, when the copper foil and the resin are to be bonded without using an adhesive, the copper foil is particularly required to adhere to the resin, but the copper foil according to the present invention is bonded to the resin, particularly to the polyimide. It can be said that it is suitable for the production of a copper clad laminate by a casting method.

  The copper-clad laminate according to 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, single-sided PWB, double-sided PWB, multilayer It can be applied to PWB (3 layers or more), and can be applied to rigid PWB, flexible PWB (FPC), and rigid flex PWB from the viewpoint of the type of insulating substrate material.

  The process for producing a printed wiring board from a copper clad laminate may be performed by a method well known to those skilled in the art. By spraying on the copper foil surface, the unnecessary copper foil can be removed to form a conductor pattern, and then the etching resist can be peeled and removed to expose the conductor pattern.

  EXAMPLES Examples of the present invention will be described below, but these are provided for better understanding of the present invention and are not intended to limit the present invention.

  As the copper foil base material, a rolled copper foil (C1100 made by Nikko Metal) having a thickness of 17 μm and a non-roughened treated foil of electrolytic copper foil were prepared. The surface roughness (Rz) of the rolled copper foil and the electrolytic copper foil was 0.7 μm and 1.5 μm, respectively.

On one side of this copper foil, a thin oxide film adhering to the surface of the copper foil base material in advance under the following conditions was removed by reverse sputtering, and a Ni—Mn alloy layer and a Cr layer were sequentially formed. The thickness of the coating layer was changed by adjusting the film formation time.
-Equipment: Batch type sputtering equipment (ULVAC, Model MNS-6000)
・ Achieving vacuum: 1.0 × 10 ⁻⁵ Pa
・ Sputtering pressure: 0.2 Pa
・ Reverse sputtering power: RF100W
·target:
Ni—Mn alloy layer = Ni—Mn alloys having various target compositions and alloy compositions shown in Table 1 below. The target composition and the coating alloy composition are not necessarily the same because the sputtering rate differs depending on the constituent elements.
For Cr layer = Cr (purity 3N)
Sputtering output: 2.5 W / cm ²
Film formation rate: About 2.0 μm was formed for each target at an output of 2.5 W / cm ² , the thickness was measured with a three-dimensional measuring device, and the sputtering rate per unit time was calculated.
-Target usage efficiency: The life of the target was defined as the time until the backing plate was exposed. The difference between "target weight before use" and "target weight used until target life" is "target usage", and "target usage" is divided by "target weight before use" Was defined as “target usage efficiency”. This “target usage efficiency” was calculated for each target.

Further, Comparative Example No. described later. In Nos. 14 and 15, Ni electroplating and chromate treatment were sequentially performed under the following conditions.
(1) Ni plating / plating bath: nickel sulfamate (110 g / L as Ni ²⁺ ), H ₃ BO ₃ (40 g / L)
・ Current density: 1.0 A / dm ²
・ Bath temperature: 55 ℃
(2) Chromate treatment / plating bath: CrO ₃ (1 g / L), Zn (powder 0.4 g), Na ₃ SO ₄ (10 g / L)
Current density: 2.0 A / dm ²
・ Bath temperature: 55 ℃

A polyimide film was bonded to the copper foil provided with the coating layer by the following procedure.
(1) Using an applicator on a copper foil of 7 cm × 7 cm, Ube Industries-made U varnish-A (polyimide varnish) was applied to a dry body to a thickness of 25 μm.
(2) The resin-coated copper foil obtained in (1) is dried at 120 ° C. for 30 minutes in an air dryer.
(3) Resin curing by heating at 350 ° C. for 30 minutes in a high-temperature heating furnace with a nitrogen flow rate set to 10 L / min.

  In addition to the polyimide film adhesion test, as a “heating test”, the polyimide film was not bonded to the copper foil provided with the coating layer, but was directly heated at 350 ° C. in a nitrogen atmosphere for 2 hours.

<Measurement of adhesion amount>
A coating layer on the surface of a 50 mm × 50 mm copper foil was dissolved in a mixed solution of HNO ₃ (2 wt%) and HCl (5 wt%), and the concentration of each metal in the solution was measured with an ICP emission spectroscopic analyzer (SII The amount of metal (μg / dm ² ) per unit area was calculated by quantification using Nanotechnology Co., Ltd. (SFC-3100). Each sample was measured five times, and the average value was defined as the amount of adhesion.
<Measurement by XPS>
The operating conditions of XPS when creating the depth profile of the coating layer are shown below.
・ Device: XPS measuring device (ULVAC-PHI, Model 5600MC)
・ Achieving vacuum: 4.5 × 10 ⁻⁷ Pa
X-ray: Monochromatic AlKα, X-ray output 210 W, detection area 800 μmφ, angle between sample and detector 45 °
Ion beam: ion species Ar ⁺ , acceleration voltage 3 kV, sweep area 3 mm × 3 mm, sputtering rate 2.0 nm / min (SiO ₂ conversion)
In the XPS measurement results, separation of chromium oxide and metallic chromium was performed using analysis software Multi Pak V7.3.1 manufactured by ULVAC.
・ Measurement is after film formation by sputtering, heat treatment (350 ° C. × 120 minutes) severer than polyimide curing conditions (350 ° C. × 30 minutes) at the time of adhesive strength measurement, and film after peeling of insulating substrate Was analyzed.
<Measurement by TEM>
The measurement conditions of TEM when the coating layer is observed by TEM are shown below. The thickness shown in the table is the thickness of the entire coating layer reflected in the observation field, and the maximum and minimum values of the thickness between 50 nm are measured for one field. The minimum value was determined, and the maximum value and the ratio of the minimum value to the maximum value were determined as a percentage. Also, in the table, the TEM observation result after “heat resistance test” means that after the polyimide film is adhered on the coating layer of the test piece by the above procedure, the test piece is placed in the following high-temperature environment and obtained. It is a TEM image after peeling a polyimide film from a piece according to 90 degree peeling method (JIS C6471 8.1). FIGS. 1 and 2 exemplarily show respective observation photographs immediately after sputtering by TEM and after heat treatment equivalent to polyimide varnish curing.
-Equipment: TEM (Hitachi, Ltd., model H9000NAR)
・ Acceleration voltage: 300 kV
-Magnification: 300,000 times-Observation field: 60 nm x 60 nm

<Adhesion evaluation>
For the copper foil laminated with polyimide as described above, the peel strength was immediately after lamination (normal state), after being left in a high-temperature environment at a temperature of 150 ° C. in an air atmosphere for 168 hours (heat resistance), and at a temperature of 40 ° C. relative The measurement was performed under three conditions: after being allowed to stand for 96 hours in a high humidity environment with a humidity of 95% air (humidity resistance). Moreover, after performing the corrosion resistance test based on (JIS Z 2371) with respect to the copper foil before laminating | stacking a polyimide, the polyimide was laminated | stacked as mentioned above and the peel strength was measured (corrosion resistance). The peel strength was measured according to the 90 ° peeling method (JIS C 6471 8.1).

<Etching evaluation>
A tape was affixed to the coating layer and etched using an etching solution (copper chloride dihydrate, ammonium chloride, aqueous ammonia, liquid temperature 50 ° C.). Etching residues (Cr, Ni, Mn) remaining on the tape after the treatment were quantified with an ICP emission spectroscopic analyzer and evaluated according to the following criteria.
×: Etching residue is 140 μg / dm ² or more Δ: Etching residue is 70 μg / dm ² or more and less than 140 μg / dm ² ○: Etching residue is less than 70 μg / dm ²

  Measurement conditions and measurement results are shown in Tables 1 and 2. SP / SP indicates that both the Ni-Mn alloy and Cr were coated by sputtering. In Tables 1 and 2, no. Examples 1 to 13 are examples according to the present invention. 14-23 are comparative examples.

(Evaluation of Examples)
As shown in Tables 1 and 2, Example No. Nos. 1 to 13 all have good peel strength and etching properties. For reference, Example No. 3 and 4 show depth profiles obtained by XPS after the heat treatment corresponding to the spatter rising and polyimide varnish curing for No. 9 copper foil. Furthermore, Example No. FIGS. 5 and 6 show depth profiles obtained by XPS when chromium after heat treatment corresponding to the spatter rising and polyimide varnish hardening is separated into metal chromium and oxide chromium, respectively.
In addition, Example No. All of the Ni-Mn targets used in Nos. 1 to 13 had good target use efficiency and were 35 to 40%.

(Evaluation of comparative example)
Comparative Example No. Nos. 14 and 15 were obtained by forming a coating layer with wet plating and chromate, and various peel strengths were poor.
Comparative Example No. No. 16 was a Ni layer formed in place of the Ni—Mn alloy layer, and the corrosion resistance was poor.
Comparative Example No. No. 17 had Mn in the Ni—Mn alloy layer of less than 15% by weight, and the corrosion resistance was poor.
Comparative Example No. No. 18 had a total of Ni and Mn of the Ni—Mn alloy layer exceeding 440 μg / dm ² , and the etching property was poor.
Comparative Example No. No. 19 had a Ni—Mn alloy layer with a total of Ni and Mn exceeding 440 μg / dm ² and had poor etching properties.
Comparative Example No. No. 20 had Mn in the Ni-Mn alloy layer exceeding 75% by weight, and the heat resistance was poor.
Comparative Example No. No. 21 had a Cr layer with Cr of more than 210 μg / dm ² and poor etching properties.
Comparative Example No. No. 22 had Cr of less than 15 μg / dm ² in the Cr layer, and various peel strengths were poor.
Comparative Example No. No. 23 had a total of Ni and Mn of the Ni—Mn alloy layer of less than 20 μg / dm ² and had poor heat resistance, corrosion resistance, and moisture resistance.
Comparative Example No. The usage efficiencies of the Ni or Ni-Mn targets used in 16 and 17 were 5 and 10%, respectively, and were lower than in the examples. Comparative Example No. The usage efficiency of the Ni-Mn target used in 18-23 was 40%, respectively, which was equivalent to the example.

1, 2 Thickness of coating layer during TEM observation

Claims (19)

A copper foil for a printed wiring board comprising a copper foil substrate and a coating layer covering at least a part of the surface of the copper foil substrate, the coating layer being laminated in order from the copper foil substrate surface, It is composed of a Ni-Mn alloy layer containing Ni and Mn and a Cr layer,
The Cr layer has a Cr content of 15 to 210 μg / dm ² , and the Ni—Mn alloy layer has a total amount of Ni and Mn of 20 to 440 μg / dm ² , respectively.
A copper foil for printed wiring board, wherein Mn is present in the Ni-Mn alloy layer in an amount of 15 to 75% by weight. ^2. The printed wiring board according to claim 1, wherein the Cr layer has a Cr coating amount of 18 to 100 μg / dm ² , and the Ni—Mn alloy layer has a total amount of Ni and Mn of 85 to 260 μg / dm ² . Copper foil. The copper foil for printed wiring boards according to claim 1, wherein Ni is present in the Ni-Mn alloy layer at a coating amount of 15 to 430 µg / dm ² and Mn of 10 to 220 µg / dm ² , respectively.   The printed wiring board according to any one of claims 1 to 3, wherein when the cross section of the coating layer is observed with a transmission electron microscope, the maximum thickness is 0.5 to 8.0 nm, and the minimum thickness is 80% or more of the maximum thickness. Copper foil.   The atomic concentration (%) of chromium in the depth direction (x: unit nm) obtained from the depth direction analysis by XPS is f (x), and the atomic concentration (%) of oxygen is g (x). The atomic concentration (%) of copper is h (x), the atomic concentration (%) of nickel is i (x), the atomic concentration (%) of manganese is j (x), and the atomic concentration of carbon (%) K (x) in the interval [0, 1.0], ∫h (x) dx / (∫f (x) dx + ∫g (x) dx + ∫h (x) dx + ∫i (x The copper foil for printed wiring boards according to any one of claims 1 to 4, wherein dx + ∫j (x) dx + + k (x) dx) is 1.0% or less. When the atomic concentration (%) in the depth direction (x: nm) of metallic chromium and oxide chromium obtained from the depth direction analysis by XPS is f ₁ (x) and f ₂ (x), respectively. In the interval [0, 1.0], 0 ≦ ∫f ₁ (x) dx / ∫f ₂ (x) dx ≦ 1.0 is satisfied, and in the interval [1.0, 2.5], 0.1 The copper foil for a printed wiring board according to any one of claims 1 to 5, wherein ≦ ∫f ₁ (x) dx / ∫f ₂ (x) dx ≦ 1.0 is satisfied.   When the surface of the coating layer was analyzed when heat treatment equivalent to polyimide curing was performed, the atomic concentration (%) of chromium in the depth direction (x: unit nm) obtained from the depth direction analysis from the surface by XPS was expressed as f. (x), atomic concentration (%) of oxygen as g (x), atomic concentration (%) of copper as h (x), atomic concentration (%) of nickel as i (x), manganese atoms If the concentration (%) is j (x) and the carbon atomic concentration (%) is k (x), in the interval [0, 1.0], ∫h (x) dx / (区間 f (x) dx + 7. (g) (x) dx + (h) x (x) dx + (i) (x) dx + (j) dx + (k) (x) dx) is 5.0% or less. The copper foil for printed wiring boards according to one item. When the surface of the coating layer is analyzed when heat treatment equivalent to polyimide curing is performed, the atomic concentration in the depth direction (x: unit nm) of chromium metal and chromium oxide obtained from the depth direction analysis from the surface by XPS (%) Are f ₁ (x) and f ₂ (x), respectively, in the interval [0, 1.0], 0.1 ≦ ∫f ₁ (x) dx / ∫f ₂ (x) dx ≦ 1 0 and in the interval [1.0, 2.5], 0.1 ≦ ∫f ₁ (x) dx / ∫f ₂ (x) dx ≦ 1.0 is satisfied. The copper foil for printed wiring boards of description.   When heat treatment equivalent to polyimide curing is performed and the surface of the coating layer is analyzed, the atomic concentration (%) of chromium in the depth direction (x: unit nm) obtained from the depth direction analysis from the surface by XPS F (x), oxygen atomic concentration (%) as g (x), copper atomic concentration (%) as h (x), nickel atomic concentration (%) as i (x), manganese When j (x) is the atomic concentration (%) of carbon and k (x) is the atomic concentration (%) of carbon, 区間 h (x) dx / (∫f (x) in the interval [0, 1.0] dx + ∫g (x) dx + ∫h (x) dx + ∫i (x) dx + ∫j (x) dx + ∫k (x) dx) is 5.0% or less. The copper foil for printed wiring boards as described in any one of Claims. When heat treatment equivalent to polyimide curing is performed and the surface of the coating layer is analyzed, the depth direction of metal chromium and oxide chromium (x: unit nm) obtained from the depth direction analysis from the surface by XPS Assuming that the atomic concentration (%) is f ₁ (x) and f ₂ (x), respectively, 0.1 ≦ ∫f ₁ (x) dx / ∫f ₂ (x) dx in the interval [0, 1.0] ≦ 1.0 is satisfied, and 0.1 ≦ ∫f ₁ (x) dx / ∫f ₂ (x) dx ≦ 1.0 is satisfied in the interval [1.0, 2.5]. A copper foil for printed wiring boards according to claim 1.   A polyamic acid solution, which is a polyimide precursor, is applied on the coating layer to a dry body of 25 μm, imidized at 120 ° C. for 30 minutes in an air dryer, and a nitrogen flow rate set to 10 L / min. A polyimide film is formed on the coating layer through a process of imidization at 350 ° C. for 30 minutes in a heating furnace, and then left at a temperature of 150 ° C. in a high-temperature environment under an air atmosphere for 168 hours, and then the polyimide film is 90 ° When the cross section of the coating layer after peeling from the coating layer according to the peeling method (JIS C 6471 8.1) is observed with a transmission electron microscope, the maximum thickness is 0.5 to 8.0 nm, and the minimum thickness is 70, which is the maximum thickness. It is% or more. The copper foil for printed wiring boards as described in any one of Claims 1-10.   When analyzing the surface of the coating layer after peeling the insulating substrate from the coating layer for the copper foil for printed wiring board formed on the insulating substrate via the coating layer, it is obtained from the depth direction analysis from the surface by XPS. The atomic concentration (%) of chromium is f (x), the atomic concentration (%) of oxygen is g (x), the atomic concentration (%) of copper is h (x), and the atomic concentration of nickel (% ) Is i (x), the atomic concentration (%) of manganese is j (x), and the distance from the surface layer where the chromium concentration is maximum is F, in the interval [0, F], ∫h (x ) dx / (∫f (x) dx + ∫g (x) dx + ∫h (x) dx + ∫i (x) dx + ∫j (x) dx) is 5.0% or less The copper foil for printed wiring boards as described in any one of -11. When analyzing the surface of the coating layer after peeling the insulating substrate from the coating layer for the copper foil for printed wiring board formed on the insulating substrate via the coating layer, it is obtained from the depth direction analysis from the surface by XPS. The atomic concentration (%) of the obtained chromium is f (x), the atomic concentration (%) of the metallic chromium is f ₁ (x), the atomic concentration (%) of the chromium oxide is f ₂ (x), and the chromium Assuming that the distances from the surface layer where the nickel and nickel concentrations are maximum are F and I, respectively, 0.1 ≦ (f ₁ (x) dx / ∫f ₂ (x) dx ≦ 1. The printed wiring according to any one of claims 1 to 12, wherein 0 is 0 and 0.1≤∫f ₁ (x) dx / ∫f ₂ (x) dx≤1.0 in the interval [F, I]. Copper foil for plates.   A copper foil base material is a rolled copper foil, The copper foil for printed wiring boards as described in any one of Claims 1-13.   A printed wiring board is a flexible printed wiring board, Copper foil for printed wiring boards as described in any one of Claims 1-14.   Printed wiring comprising sequentially covering at least a part of the surface of a copper foil base material with a Ni-Mn alloy layer having a thickness of 0.3 to 5.0 nm and a Cr layer having a thickness of 0.2 to 3.0 nm by sputtering. Manufacturing method of copper foil for board.   The copper clad laminated board provided with the copper foil as described in any one of Claims 1-15.   The copper clad laminate according to claim 17, wherein the copper foil has a structure bonded to polyimide.   A printed wiring board made of the copper-clad laminate according to claim 17 or 18.