KR20110063804A - Copper foil for printed wiring boards - Google Patents

Abstract

∫f₁(x)dx/∫f₂(x)dx

1.0 을 만족한다.The copper foil for printed wiring boards which is excellent in both adhesiveness with an insulated substrate, and etching property, and is suitable for fine pitch formation is provided. The copper foil for printed wiring boards is equipped with a copper foil base material and the coating layer which coat | covers at least one part of the copper foil base material surface. The coating layer consists of an intermediate | middle layer which consists of a single metal, or an alloy, and a Cr layer laminated | stacked in order from the copper foil base material surface. Cr is present in the coating layer at a coating amount of 18 to 180 µg / dm ² , and the atomic concentration (%) of the metal chromium in the depth direction (x: unit nm) obtained from the depth direction analysis from the surface by XPS is determined by f _1. (x), the atomic concentration (%) of chromium oxide is f ₂ (x), the atomic concentration (%) of all chromium is f (x), and (f (x) = f ₁ (x) + f ₂ (x)), the atomic concentration (%) of nickel is g (x), the atomic concentration (%) of copper is h (x), and the atomic concentration (%) of oxygen is i (x). When the atomic concentration (%) of carbon is j (x) and the sum of the atomic concentrations of other metals is k (x), ∫h (x) dx / (∫f in the section [0, 1.0]). (x) dx + ∫g (x) dx + ∫h (x) dx + ∫i (x) dx + ∫j (x) dx + ∫k (x) dx) is 10% or less, and ∫f ₂ (x) dx / ( ∫f (x) dx + ∫g (x) dx + ∫h (x) dx + ∫i (x) dx + ∫j (x) dx + ∫k (x) dx) is 20% or more, and in the interval [1.0, 2.5] In 0.1

∫f ₁ (x) dx / ∫f ₂ (x) dx

Satisfies 1.0

Description

Copper foil for printed wiring board {COPPER FOIL FOR PRINTED WIRING BOARDS}

This invention relates to the copper foil for printed wiring boards, and especially relates to the copper foil for flexible printed wiring boards.

Printed wiring boards have made great progress over this half century, reaching today's use in virtually any electronic device. In recent years, with the increase in demand for miniaturization and high performance of electronic devices, high-density mounting of high-frequency components and high frequency of signals have progressed, and thus, printed circuit boards are required to have a finer conductor pattern (fine pitch) or higher frequency response. .

A printed wiring board is generally manufactured by adhering an insulated substrate to copper foil, making it a copper clad laminated board, and forming a conductor pattern on the copper foil surface by etching. Therefore, adhesiveness and etching property with an insulated substrate are calculated | required by the copper foil for printed wiring boards.

As a technique of improving the adhesiveness with an insulated substrate, it is common to perform the surface treatment which forms an unevenness | corrugation on the copper foil surface called a roughening process. For example, a copper sulfate acid plating bath is used on the M surface (rough surface) of an electrolytic copper foil to electrodeposit a large amount of copper in a resin shape or a globular shape to form fine irregularities, thereby improving adhesiveness by the anchoring effect. There is a way. After the roughening treatment, a chromate treatment, a treatment with a silane coupling agent or the like is generally performed to further improve the adhesive properties.

Moreover, the method of forming metal layers or alloy layers, such as tin, chromium, copper, iron, cobalt, zinc, nickel, on the smooth copper foil surface in which the roughening process is not performed is also known.

Since polyimide is often used for the insulated substrate adhere | attached to copper foil, the method of coat | covering the copper foil surface with chromium with high adhesive strength with a polyimide is common.

Moreover, as a surface treatment with respect to the smooth copper foil surface, the 1st metal layer which prevents the diffusion of Cu atom with respect to a polyimide layer is formed, and the adhesiveness with an insulating substrate as a 2nd metal layer on the said 1st metal layer is carried out. By forming a good Cr layer thinly to a good etching property, the technique which seeks to acquire the favorable adhesiveness with an insulating substrate and a favorable etching property simultaneously is researched and developed. This is because when the Cu atom or the Cu oxide diffuses to the polyimide side, the polyimide layer near the adhesive interface becomes brittle and becomes a starting point of peeling.

As a method of coating a chromium layer on the copper foil surface, there exist a wet processing method, a dry processing method, etc. Among these, as a method of coating a chromium layer on the surface by a wet treatment, a method of forming a Zn layer or a Zn alloy layer on the copper foil surface, and further forming a chromate layer on the layer, and Zn on the copper foil surface There is a method of forming a layer that does not contain and not forming a chromate layer on the layer. The former example is disclosed by patent document 1, and the latter example is disclosed by patent document 2. As shown in FIG. In the case of forming a chromate layer on the Zn layer or a Zn alloy layer, in between the Cr ^{+ 6} and a solution of Zn Zn or Zn alloy layer is a layer metathesis up, the hydroxides of Cr are precipitated. In this method, Cr is precipitated in the hydroxide state. For this reason, the valence of the precipitated Cr is not zero, but has three sides which are considered to be excellent in adhesiveness with a polyimide.

In addition, Patent Document 3 discloses a method using a dry process. Patent Literature 3 forms a Ni-Cr alloy layer on the surface of the copper foil, and forms an oxide layer having a predetermined thickness on the surface of the alloy layer, so that the surface of the copper foil is smooth and the adhesiveness with the resin substrate is low even when the anchor effect is low. This large increase is described. Then, a Ni-Cr alloy layer having a thickness of 1 to 100 nm is deposited on the surface, and a Cr oxide layer having a thickness of 0.5 to 6 nm is formed on the surface of the alloy layer, and the average surface roughness (Rz) JIS of the outermost surface is The copper foil for printed wiring boards of 2.0 micrometers or less is disclosed.

Japanese Laid-Open Patent Publication 2005-344174 Japanese Unexamined Patent Publication No. 2007-007937 Japanese Unexamined Patent Publication No. 2007-207812

In the various conventional techniques mentioned above, the method of improving adhesiveness by a roughening process is disadvantageous from a viewpoint of circuit formation of a fine pitch. That is, when the conductor spacing is narrowed by fine pitching, the roughening treatment part remains on the insulating substrate after the circuit formation by etching, and there is a fear of causing insulation deterioration. In order to prevent this, trying to etch the whole roughening surface requires a long etching time and it becomes impossible to maintain a predetermined wiring width.

From the viewpoint of adhesive strength, the method of laminating the polyimide on the smooth copper foil surface is disadvantageous compared to the method of laminating the polyimide on the roughened surface. On the surface of the roughening treatment, the adhesive strength is obtained by the anchor effect, whereas when the roughening treatment is not performed, the anchoring effect is not obtained, and the Cu atoms diffuse into the polyimide, thereby making the polyimide layer near the interface weak. It is because this part becomes a starting point of peeling.

In the dry process, for example, the method of forming the Ni layer and the Ni-Cr alloy layer has a great room for improvement in the basic property of adhesion with an insulating substrate. It it does not have the electronic adhesive of the preferred Cr ³⁺ as polyimide is present, the latter is caused to lower the ratio of the Cr ^{+ 3,} because the coexistence with Ni coating.

In the method of forming the Cr layer by dry treatment, a relatively high adhesive strength is obtained at room temperature. When the laminate is subjected to a thermal history, if the layer thickness is thin, Cu atoms derived from copper foil diffuse the Cr layer and It penetrates into a mid layer, and adhesive strength deteriorates. On the other hand, when the Cr layer is thick enough to prevent diffusion of Cu atoms, the etching property of the surface treatment layer is inferior. This is a phenomenon called "etching residue" in which Cr remains on the insulating substrate after the etching process is performed to form a circuit pattern.

Moreover, the surface treatment layer of patent documents 1 and 2 is formed by electroplating. At this time, the copper foil itself acts as an electrode of the electrochemical reaction. Since the surface of copper foil has unevenness | corrugation, such as an oil pit, and the inclusion of several 100 nm exists in the vicinity of the surface, the said part has the flow of an electron, and the ultra-thin surface treatment layer has a uniform thickness. It is difficult to form the resin and make it compatible with the adhesiveness and the etching property with the polyimide.

In addition, in order to attach Cr effective for adhesion with the polyimide to the copper foil surface, it is necessary to form a chromate layer on the Zn layer or the Zn alloy layer, but as described in Patent Document 1, the chromate layer on the Ni-Zn alloy layer The present inventors found that the concentration of chromium oxide in the vicinity of the bonding interface was lowered and high adhesive strength could not be obtained when the was formed. In addition, there is a limit to the amount of deposition of Cr because the case does not form a chromate layer on the Zn layer or the Zn alloy layer as described in Patent Document 2, can be used for a substitution reaction between Zn and Cr ^{+ 6.}

Then, an object of this invention is to provide the copper foil for printed wiring boards which is excellent in both adhesiveness and etching property with an insulated substrate, and is suitable for fine pitch formation.

Conventionally, it was a general understanding that thinning the coating layer lowers the adhesive strength. However, as a result of earnestly examining the present inventors, when the Cr layer is uniformly formed with a nanometer-class ultra-thin thickness, the concentration of oxide Cr near the bonding interface can be made higher than that of the wet plating, and the excellent insulating substrate and The adhesiveness of was obtained. By making thickness extremely thin, the usage-amount of Cr with low etching property is reduced and it is advantageous for etching property from a uniform point of a coating layer. Moreover, by forming the layer which prevents the diffusion of Cu atoms directly under Cr mentioned above, it is possible to provide a copper clad laminated substrate that can withstand harsh use environments.

∫f₁(x)dx/∫f₂(x)dx

1.0 을 만족하는 프린트 배선판용 동박이다.This invention completed based on the above knowledge, In one aspect, the copper foil base material and the copper foil for printed wiring boards provided with the coating layer which coat | covers at least one part of the copper foil base material surface, A coating layer is laminated | stacked sequentially from the copper foil base material surface. Composed of a single layer or an alloy of a metal, and a Cr layer, wherein the coating layer has Cr in a coating amount of 18 to 180 µg / dm ² , and the depth direction (x) obtained from the depth direction analysis from the surface by XPS. : Atomic concentration (%) of metal chromium in unit nm) is f ₁ (x), and atomic concentration (%) of oxide chromium is f ₂ (x) To, and is a, and an atomic concentration (%) of total chromium to f (x) (f (x) = f ₁ (x) + f ₂ (x)), nickel atom concentration (%) by g (x) , The atomic concentration (%) of copper is h (x), the atomic concentration (%) of oxygen is i (x), the atomic concentration (%) of carbon is j (x), and other metals If the sum of the atomic concentrations 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 10% or less, and ∫f ₂ (x) dx / (∫f (x) dx + ∫g (x) dx + ∫h (x) dx + ∫i (x) dx + ∫j (x) dx + ∫k (x) dx) is 20% or more, and 0.1 in the interval [1.0, 2.5]

∫f ₁ (x) dx / ∫f ₂ (x) dx

Copper foil for printed wiring boards which satisfy 1.0.

In one Embodiment of the copper foil for printed wiring boards which concerns on this invention, Cr exists in the coating amount of 30-45 g / dm <^2> .

In another embodiment of the copper foil for printed wiring boards which concerns on this invention, Cr exists in the coating amount of 36-90 microgram / dm <^2> .

In another embodiment of the copper foil for printed wiring boards which concerns on this invention, Cr exists in the coating amount of 36-75 microgram / dm <^2> .

In another embodiment of the copper foil for printed wiring boards which concerns on this invention, an intermediate | middle layer contains at least any 1 type of Ni, Mo, Ti, Zn, Co, V, Sn, Mn, and Cr.

In another embodiment of the copper foil for printed wiring boards which concerns on this invention, the coating layer is an intermediate | middle layer consisting of any 1 type of Ni, Mo, Ti, Zn, and Co laminated in order from the copper foil base material surface, and Cr layer In the intermediate layer, any one of Ni, Mo, Ti, Zn and Co is present in a coating amount of 15 to 1030 µg / dm ² .

In another embodiment of the copper foil for printed wiring boards which concerns on this invention, Ni is 15-440 microgram / dm <^2> , Ni is 25-1030 microgram / dm <^2> , Ti is 15-140 microgram / dm <^2> , Zn is present in a coating amount of 15 to 750 μg / dm ² or Co of 25 to 1030 μg / dm ² .

In another embodiment of the copper foil for printed wiring boards which concerns on this invention, the coating layer is an alloy of at least any 2 types of Ni, Zn, V, Sn, Mn, Cr, and Cu laminated | stacked in order from the copper foil base material surface. It consists of the intermediate | middle layer comprised and the Cr layer, and in this intermediate | middle layer, any two species of Ni, Zn, V, Sn, Mn, and Cr exist in 20-1700 microgram / dm <^2> of coating amount.

In another embodiment of the copper foil for printed wiring boards which concerns on this invention, an intermediate | middle layer is comprised from Ni and Ni alloy which consists of any 1 type of Zn, V, Sn, Mn, and Cr.

In still another embodiment of a copper foil for printed wiring board according to the present invention, the intermediate layer, the coating amount is 15 ~ 1000 ㎍ / dm ² of Ni, and 5 ~ 750 ㎍ / dm ² is made of a Zn Ni-Zn alloy, the total coating Ni-V alloy consisting of Ni and V having an amount of 20 to 600 µg / dm ² , Ni-Sn alloy consisting of Ni and Sn having a total coating amount of 18 to 450 µg / dm ² , and coating amount of 15 to 450 µg / dm ² It is composed of Ni and 5 ~ 200 ㎍ / dm ² of Ni-Mn alloy, the coating 20 ~ 440 ㎍ / dm ² of Ni, and 5 ~ 110 ㎍ / dm Ni- Cr alloy comprising ² was the Cr amount is made of Mn.

In another embodiment of the copper foil for printed wiring boards which concerns on this invention, an intermediate | middle layer is comprised from Cu and Cu alloy which consists of any 1 type or 2 types of Zn and Ni.

In still another embodiment of a copper foil for printed wiring board according to the present invention, the intermediate layer, the coating amount of the Zn 15 ~ 750 ㎍ / dm ² of Cu-Zn alloy, Ni-coated amount of 15 ~ 440 ㎍ / dm ² of Cu- A Ni alloy or a Cu-Ni-Zn alloy having a Ni coating amount of 15 to 1000 µg / dm ² and a Zn coating amount of 5 to 750 µg / dm ² .

In another embodiment of the copper foil for printed wiring boards which concerns on this invention, when the cross section of a coating layer is observed with a transmission electron microscope, the maximum thickness is 0.5-12 nm and the minimum thickness is 80% or more of the maximum thickness.

∫f₁(x)dx/∫f₂(x)dx

1.0 을 만족한다. In another embodiment of the copper foil for printed wiring boards which concerns on this invention, when the heat processing corresponded to polyimide hardening, the metal of the depth direction (x: unit nm) obtained from the depth direction analysis from the surface by XPS The atomic concentration (%) of chromium is f ₁ (x), the atomic concentration (%) of oxide chromium is f ₂ (x), and the atomic concentration (%) of all chromium is f (x) (f (x) = f ₁ (x) + f ₂ (x)), the atomic concentration (%) of nickel is g (x), the atomic concentration (%) of copper is h (x), and the atomic concentration of oxygen If (%) is i (x), the atomic concentration (%) of carbon is j (x), and the sum of the atomic concentrations of the other metals 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 10% or less , ∫f ₂ (x) dx / (∫f (x) dx + ∫g (x) dx + ∫h (x) dx + ∫i (x) dx + ∫j (x) dx + ∫k (x) dx) is 20% this Phase and 0.1 in the interval [1.0, 2.5]

∫f ₁ (x) dx / ∫f ₂ (x) dx

Satisfies 1.0

∫f₁(x)dx/∫f₂(x)dx

1.0 을 만족한다. In another embodiment of the copper foil for printed wiring boards which concerns on this invention, it is the copper foil for printed wiring boards which heat-processed corresponded to polyimide hardening, The depth direction (x: unit obtained from the depth direction analysis from the surface by XPS) Nm), the atomic concentration (%) of metal chromium is f ₁ (x), the atomic concentration (%) of oxide chromium is f ₂ (x), and the atomic concentration (%) of all chromium is f (x) (F (x) = f ₁ (x) + f ₂ (x)), the atomic concentration (%) of nickel is g (x), the atomic concentration (%) of copper is h (x), If the atomic concentration (%) of oxygen is i (x), the atomic concentration (%) of carbon is j (x), and the sum of the atomic concentrations of other metals 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) 10% or less, ∫f ₂ (x) dx / (∫f (x) dx + ∫g (x) dx + ∫h (x) dx + ∫i (x) dx + ∫j ( x) dx + ∫k (x) dx) is 20% or more, and is 0.1 in the interval [1.0, 2.5].

∫f ₁ (x) dx / ∫f ₂ (x) dx

Satisfies 1.0

∫f₁(x)dx/∫f₂(x)dx

1.0 이고, ∫h(x)dx/(∫f(x)dx＋∫g(x)dx＋∫h(x)dx＋∫i(x)dx＋∫j(x)dx＋∫k(x)dx) 가 10 ％ 이하를 만족한다.In another embodiment of the copper foil for printed wiring boards which concerns on this invention, when analyzing the surface of the coating layer after peeling an insulating substrate from a coating layer with respect to the copper foil for printed wiring boards with which the insulation substrate was formed through the coating layer, The atomic concentration (%) of the metal chromium in the depth direction (x: unit nm) obtained from the depth direction analysis from the surface by the surface is set to f ₁ (x), and the atomic concentration (%) of the oxide chromium is set to f ₂ (x). Let the atomic concentration (%) of all chromium be f (x) (f (x) = f ₁ (x) + f ₂ (x)), and the atomic concentration (%) of nickel be g (x), Atomic concentration (%) of copper is h (x), Atomic concentration (%) of oxygen is i (x), Atomic concentration (%) of carbon is j (x), and atoms of other metals If the sum of the concentrations is k (x) and the distance from the surface layer where the concentration of the metal chromium is maximum is F, the interval is in the range [0, F]. Standing 0.1

∫f ₁ (x) dx / ∫f ₂ (x) dx

1.0 and ∫h (x) dx / (∫f (x) dx + ∫g (x) dx + ∫h (x) dx + ∫i (x) dx + ∫j (x) dx + ∫k (x) dx) is 10 It satisfies% or less.

In another embodiment of the copper foil for printed wiring boards which concerns on this invention, a copper foil base material is a rolled copper foil.

In another embodiment of the copper foil for printed wiring boards which concerns on this invention, a printed wiring board is a flexible printed wiring board.

This invention is another one side. WHEREIN: It is the copper clad laminated board provided with the copper foil which concerns on this invention.

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

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

ADVANTAGE OF THE INVENTION According to this invention, the copper foil for printed wiring boards which is excellent in both adhesiveness with an insulating substrate and etching property, and suitable for fine pitch formation is obtained. Moreover, this invention is applicable also to the technique of laminating | stacking resin, such as a polyimide or polyamide, in a metal bath for an electromagnetic shield, a high frequency shield, and insulation.

1 is a TEM image (cross section) of a copper foil (after film formation) of Example 1. FIG.
It is a depth profile by XPS of the copper foil (after heat processing corresponded to polyimide varnish hardening) of Example 17.
It is a depth profile by XPS of the copper foil (after electroplating) of the comparative example 29.
It is a depth profile by XPS of the copper foil (after electroplating) of the comparative example 30.

Carrying out the invention  Form for

(Copper foil mention)

Although there is no restriction | limiting in particular in the form of the copper foil base material which can be used for this invention, It can typically be used in the form of a rolled copper foil and an electrolytic copper foil. Generally, an electrolytic copper foil is manufactured by electrolytically depositing copper on a titanium or stainless steel drum from a copper sulfate plating bath, and a rolled copper foil is manufactured by repeating plastic working and heat processing by a rolling roll. Rolled copper foil is often applied to the application which requires flexibility.

As the material of the copper foil base material, for example, copper containing Sn-containing copper, Ag-containing copper, Cr, Zr, or Mg, in addition to high-purity copper such as tough pitch copper or oxygen-free copper, which is usually used as a conductor pattern of a printed wiring board. Copper alloys, such as a Coleson-type copper alloy which added the alloy, Ni, and Si etc., can also be used. In addition, when using the term "copper foil" independently in this specification, a copper alloy foil shall also be 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 suitably to the thickness suitable for a printed wiring board. For example, it can be about 5-100 micrometers. However, when aiming at formation of a fine pattern, it is 30 micrometers or less, Preferably it is 20 micrometers or less, and is typically about 5-20 micrometers.

It is preferable that the copper foil base material used for this invention is not roughened. Conventionally, the case which forms a micrometer grade unevenness | corrugation on the surface by special plating, performs surface roughening process, and has adhesiveness with resin by the physical anchor effect was common. On the other hand, the fine pitch and the high frequency electrical characteristics are considered to be a smooth foil, and act in an unfavorable direction in the roughened foil. Moreover, since a roughening process process is abbreviate | omitted, there exists also the effect of economical efficiency and productivity improvement. Therefore, the foil used by this invention is foil which does not give a roughening process in particular.

(Coating layer)

The coating layer is formed in at least one part of the copper foil base material surface. Although there is no restriction | limiting in particular in the point to coat | cover, It is common to set it as the point where adhesion | attachment with an insulating substrate is intended. The presence of the coating layer improves the adhesion to the insulating substrate. The coating layer consists of an intermediate | middle layer and Cr layer laminated | stacked in order from the copper foil base material surface. It is preferable that an intermediate | middle layer contains at least any 1 type of Ni, Mo, Ti, Zn, Co, V, Sn, Mn, and Cr. The intermediate layer may be composed of a single metal, and is preferably composed of any one of Ni, Mo, Ti, Zn and Co, for example. The intermediate layer may be made of an alloy, for example, preferably composed of at least any two kinds of alloys of Ni, Zn, V, Sn, Mn, Cr, and Cu. Moreover, the intermediate | middle layer may be comprised with Ni, Ni alloy which consists of any 1 type of Zn, V, Sn, Mn, and Cr, and is comprised with Cu, Cu alloy which consists of any 1 type or 2 types of Zn and Ni. You may be. In general, the adhesion between the copper foil and the insulating substrate tends to be lowered when placed under a high temperature environment, which is thought to occur by copper thermally diffusing to the surface and reacting with the insulating substrate. In this invention, thermal diffusion of copper can be prevented by forming the said intermediate | middle layer excellent in copper diffusion prevention on a copper foil base material beforehand. Here, among the various intermediate layers formed to prevent the diffusion of copper, the Cu alloy layer contains copper that is not intended to diffuse on the surface, but since copper is alloyed, there is no diffusion to the surface, and it has good adhesion. At the same time, the etching property is not adversely affected.

Moreover, by forming the Cr layer which is excellent in adhesiveness with an insulating substrate rather than the said intermediate | middle layer on this intermediate | middle layer, adhesiveness with an insulating substrate can be improved further. Since the thickness of the Cr layer can be made thin due to the presence of the intermediate layer, the adverse effect on the etching property can be reduced. In addition, the adhesiveness referred to in this invention also refers to the adhesiveness (heat resistance) after putting under high temperature, and the adhesiveness (moisture resistance) after putting under high humidity in addition to the adhesiveness in a steady state.

In the copper foil for printed wiring boards which concerns on this invention, a coating layer is extremely thin and thickness is uniform. Although it is not clear why such a structure improves the adhesiveness with an insulating substrate, after forming the Cr single layer film which is very excellent in adhesiveness with resin as an outermost surface on an intermediate | middle layer, after high temperature heat processing at the time of imidation (about 350 degreeC) 30 minutes to several hours), it is presumed to be because the single-layer coating structure having high adhesion is maintained. Moreover, it is thought that etching property improved by reducing the usage-amount of Cr by making a coating layer into ultra-thin, and making into a two layer structure of an intermediate | middle layer and a Cr layer.

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

(1) Identification of coating layer

In the present invention, at least part of the surface of the copper foil material is coated in the order of the intermediate layer and the Cr layer. The identification of these coating layers can be carried out by argon sputtering from the surface layer with a surface analysis apparatus such as XPS or AES, conducting chemical analysis in the depth direction, and identifying the intermediate layer and the Cr layer depending on the presence of each detection peak. Moreover, the order which coat | covered from the position of each detection peak can be confirmed.

(2) adhesion amount

On the other hand, since these intermediate | middle layers and Cr layers are very thin, it is difficult to evaluate exact thickness with XPS and AES. Therefore, in this invention, the thickness of an intermediate | middle layer and a Cr layer shall be evaluated by the weight of the coating metal per unit area. Cr exists in the coating layer which concerns on this invention in the coating amount of 18-180 microgram / dm <^2> . If Cr is less than 18 µg / dm ^2, sufficient peel strength is not obtained. If Cr is more than 180 µg / dm ² , the etching property tends to be significantly lowered. The coating amount of Cr is preferably 30 to 145 μg / dm ² , more preferably 36 to 90 μg / dm ² , still more preferably 36 to 75 μg / dm ² .

Moreover, when the intermediate | middle layer consists of any 1 type of Ni, Mo, Ti, Zn, and Co, in the intermediate | middle layer, the coating amount of 15-1030 microgram / dm <^2> in any one species of Ni, Mo, Ti, Zn, and Co is carried out. It is preferable to exist as. At this time, sufficient peeling strength is not obtained when the coating amount is less than 15 µg / dm ² , and when it exceeds 1030 µg / dm ² , the etching property tends to be significantly lowered.

In this case, the intermediate layer has 15 to 440 µg / dm ² of Ni, 25 to 1030 µg / dm ^{2 of} Mo, 15 to 140 µg / dm ^{2 of} Ti, 15 to 750 µg / dm ^{2 of} Zn, or 25 to Co. It is preferable to exist in the coating amount of -1030 microgram / dm <^2> .

Moreover, when an intermediate | middle layer consists of at least 2 types of alloys of Ni, Zn, V, Sn, Mn, Cr, and Cu, At least 2 of Ni, Zn, V, Sn, Mn, Cr is contained in the intermediate | middle layer. It is preferable that the species exists at a coating amount of 20 to 1700 µg / dm ² . At this time, sufficient peeling strength is not obtained when the coating amount is less than 20 µg / dm ² , and when it exceeds 1700 µg / dm ² , the etching property tends to be significantly lowered.

Moreover, when an intermediate | middle layer is comprised from Ni and the Ni alloy which consists of any 1 type of Zn, V, Sn, Mn, and Cr, the intermediate | middle layer has Ni and 5-750 which are 15-1000 micrograms / dm <^2> of coating amounts. is made of a Zn ㎍ / dm ² Ni-Zn alloy, the total coating amount of 20 ~ 600 ㎍ / dm ² in the amount of Ni-V alloy, the total coating made of Ni and V 18 ~ 450 ㎍ / dm ² is composed of Ni and Sn Ni-Sn alloy, Ni-Mn alloy consisting of Ni having a coating amount of 15 to 450 μg / dm ² and Mn of 5 to 200 μg / dm ² , Ni having a coating amount of 20 to 440 μg / dm ² and 5 to 110 μg / it is composed of Ni-Cr alloy consisting dm ² of Cr is preferred.

Moreover, when an intermediate | middle layer consists of Cu and Cu alloy which consists of any 1 type or 2 types of Zn and Ni, the intermediate | middle layer has Cu-Zn alloy whose Ni coating amount is 15-750 microgram / dm <^2> , Ni It is preferable that a Cu-Ni alloy having a coating amount of 15 to 440 µg / dm ² or a Cu-Ni-Zn alloy having a Ni coating amount of 15 to 1000 µg / dm ² and a Zn coating amount of 5 to 750 µg / dm ² is preferred. Do.

(3) Observation by transmission electron microscope (TEM)

When the cross section of the coating layer which concerns on this invention is observed with the transmission electron microscope, the maximum thickness is 0.5 nm-12 nm, Preferably it is 1.0-2.5 nm, The minimum thickness is 80% or more of the maximum thickness, Preferably it is 85% As mentioned above, it is a coating layer with very little dispersion | variation. This is because, in the heat resistance test and the moisture resistance test, when the coating layer thickness is less than 0.5 nm, the deterioration of the peel strength is large, and when the thickness exceeds 12 nm, the etching property is lowered. When the minimum value of the thickness is 80% or more of the maximum value, the thickness of this coating layer is very stable and hardly changes even after the heat resistance test. In the observation by TEM, the clear boundary between the intermediate layer and the Cr layer in the coating layer is difficult to find, and looks like a monolayer (see FIG. 1). According to the examination result of this inventor, it is thought that the coating layer learned by TEM observation is a layer mainly having Cr, and an intermediate | middle layer exists in the copper foil base material side. Therefore, in the present invention, the thickness of the coating layer in the case of TEM observation is defined as the thickness of the coating layer which looks like a single layer. However, depending on the observation point, there may be a place where the boundary of the coating layer is unclear, and such a point is excluded from the measurement point of the thickness.

Since diffusion of Cu is suppressed by the structure of this invention, it is considered to have a stable thickness. The copper foil of this invention adhere | attaches a polyimide film, and after peeling resin after passing through a heat resistance test (168 hours left in a high-temperature environment in air atmosphere at a temperature of 150 degreeC), the thickness of a coating layer hardly changes, but the maximum thickness Is 0.5 to 12 nm, and 80% of the maximum thickness can be maintained even at the minimum thickness.

(4) oxidation state of the coating layer surface

First, it is preferable that internal copper is not diffused in the coating layer outermost surface (range of 0 to 1.0 nm from the surface) to increase the adhesive strength. Therefore, in the copper foil for printed wiring board according to the present invention, a depth direction (x: unit ㎚) obtained from the depth-wise analysis from the surface by XPS, and the atomic concentration (%) of metal chromium to f ₁ (x), oxide The atomic concentration (%) of chromium is f ₂ (x), the atomic concentration (%) of all chromium is f (x) (f (x) = f ₁ (x) + f ₂ (x)), and nickel Let the atomic concentration (%) of g be (x), the atomic concentration (%) of copper be h (x), the atomic concentration (%) of oxygen be i (x), and the atomic concentration (%) of carbon. ) Is j (x) and the sum of the atomic concentrations of the other metals is k (x), where ∫h (x) dx / (∫f (x) dx + ∫g ( It is preferable to make x) dx + ∫h (x) dx + ∫i (x) dx + ∫j (x) dx + ∫k (x) dx) 10% or less.

In addition, when a heat treatment corresponding to the polyimide cured, the depth direction (x: unit ㎚) obtained from the depth-wise analysis from the surface by XPS, and the atomic concentration (%) of metal chromium to f ₁ (x) , The atomic concentration (%) of oxide chromium is f ₂ (x), and the atomic concentration (%) of all chromium is f (x) (f (x) = f ₁ (x) + f ₂ (x)) The atomic concentration (%) of nickel is g (x), the atomic concentration (%) of copper is h (x), the atomic concentration (%) of oxygen is i (x), and the atomic concentration of carbon. When (%) is j (x) and the sum of the atomic concentrations of other metals is k (x), ∫h (x) dx / (∫f (x) dx + ∫) in the interval [0, 1.0] It is preferable that g (x) dx + ∫h (x) dx + ∫i (x) dx + ∫j (x) dx + ∫k (x) dx) is 10% or less.

Moreover, when analyzing the surface of the coating layer after peeling an insulating substrate from the coating layer with respect to the copper foil for printed wiring boards with which the insulation substrate was formed through the coating layer, the depth direction (x: unit obtained from the depth direction analysis from the surface by XPS) Nm), the atomic concentration (%) of metal chromium is f ₁ (x), the atomic concentration (%) of oxide chromium is f ₂ (x), and the atomic concentration (%) of all chromium is f (x) (F (x) = f ₁ (x) + f ₂ (x)), the atomic concentration (%) of nickel is g (x), the atomic concentration (%) of copper is h (x), The atomic concentration (%) of oxygen is i (x), the atomic concentration (%) of carbon is j (x), the sum of the atomic concentrations of other metals is k (x), and the concentration of metal chromium If the distance from the surface layer where F is the maximum is F, then ∫h (x) dx / (∫f (x) dx + ∫g (x) dx + ∫h (x) dx + ∫i () in the interval [0, F]. x) dx + ∫j (x) dx + ∫k (x) dx) is 10 Or less are preferred.

∫f₁(x)dx/∫f₂(x)dx

1.0 을 만족하는 것이 바람직하다.On the outermost surface of the coating layer, chromium contains both metal chromium and chromium oxide. Although chromium is preferable from the viewpoint of preventing diffusion of copper inside and securing adhesion, chromium is preferable in obtaining good etching properties. Oxides are preferred. Therefore, in achieving both the etching property and the adhesive force, the atomic concentration (%) of the metal chromium in the depth direction (x: unit nm) obtained from the depth direction analysis from the surface by XPS is assumed to be f ₁ (x). The atomic concentration (%) of chromium is f ₂ (x), the atomic concentration (%) of all chromium is f (x) (f (x) = f ₁ (x) + f ₂ (x)), and nickel Let the atomic concentration (%) of g be (x), the atomic concentration (%) of copper be h (x), the atomic concentration (%) of oxygen be i (x), and the atomic concentration (%) of carbon. ) Is j (x) and the sum of the atomic concentrations of the other metals is k (x), where ∫f ₂ (x) dx / (∫f (x) dx + ∫g in the interval [0, 1.0] (x) dx + ∫i (x) dx + ∫j (x) dx + ∫k (x) dx) is 20% or more, and 0.1 in the interval [1.0, 2.5]

∫f ₁ (x) dx / ∫f ₂ (x) dx

It is preferable to satisfy 1.0.

∫f₁(x)dx/∫f₂(x)dx

1.0 을 만족하는 것이 바람직하다.In addition, when a heat treatment corresponding to the polyimide cured, the depth direction (x: unit ㎚) obtained from the depth-wise analysis from the surface by XPS, and the atomic concentration (%) of metal chromium to f ₁ (x) , The atomic concentration (%) of oxide chromium is f ₂ (x), and the atomic concentration (%) of all chromium is f (x) (f (x) = f ₁ (x) + f ₂ (x)) The atomic concentration (%) of nickel is g (x), the atomic concentration (%) of copper is h (x), the atomic concentration (%) of oxygen is i (x), and the atomic concentration of carbon. When (%) is j (x) and the sum of other metal atom concentrations is k (x), ∫f ₂ (x) dx / (∫f (x) dx + ∫) in the interval [0, 1.0] g (x) dx + ∫h (x) dx + ∫i (x) dx + ∫j (x) dx + ∫k (x) dx) is 20% or more and 0.1 in the interval [1.0, 2.5]

∫f ₁ (x) dx / ∫f ₂ (x) dx

It is preferable to satisfy 1.0.

∫f₁(x)dx/∫f₂(x)dx

1.0 을 만족하는 것이 바람직하다.In addition, the thermal treatment corresponding to the polyimide cured as a copper foil for printed circuit board, a depth direction (x: unit ㎚) obtained from the depth-wise analysis from XPS surface atomic concentration (%) of metal chromium of f a ₁ (x) The atomic concentration (%) of oxide chromium is f ₂ (x), the atomic concentration (%) of all chromium is f (x), and (f (x) = f ₁ (x) + f ₂ (x)). ), The atomic concentration (%) of nickel is g (x), the atomic concentration (%) of copper is h (x), the atomic concentration (%) of oxygen is i (x), and the atom of carbon If the concentration (%) is j (x) and the sum of the atomic concentrations of the other metals is k (x), ∫f ₂ (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 20% or more and 0.1 in the interval [1.0, 2.5]

∫f ₁ (x) dx / ∫f ₂ (x) dx

It is preferable to satisfy 1.0.

The chromium concentration and the oxygen concentration are respectively calculated from the peak intensities of the Cr2p orbit and the O1s orbit obtained from the depth direction analysis from the surface by XPS. In addition, the depth direction: the distance (x units n) to be taken as the distance calculated by the sputter rate of the SiO ₂ equivalent. The chromium concentration is the total value of the oxide concentration and the metal chromium concentration, and can be analyzed by separating the concentration of the oxide chromium and the metal chromium concentration.

(Manufacturing method of copper foil which concerns on this invention)

The copper foil for printed wiring boards which concerns on this invention can be formed by sputtering method. That is, by the sputtering method, at least a part of the surface of the copper foil substrate is 0.25-5.0 nm thick, preferably 0.3-4.0 nm, more preferably 0.5-3.0 nm intermediate layer and 0.25-2.5 nm thick, preferably 0.4- It can manufacture by covering in order with the Cr layer which is 2.0 nm, More preferably, it is 0.5-1.0 nm. When such an ultrathin film is laminated by electroplating, a deviation occurs in a desired thickness, and the peel strength is likely to decrease after the heat and moisture resistance test.

The thickness here is not the thickness determined by the above-mentioned XPS or TEM, but the thickness derived from the film formation rate of sputtering. The film-forming speed | rate under any sputtering conditions can sputter | spatter 0.1 micrometer (100 nm) or more, and can measure it from the relationship between sputter time and sputter | spatter thickness. If the film-forming speed | rate under the said sputtering conditions can be measured, a sputter time is set according to thickness. In addition, sputter | spatter may be performed in either a continuous or a batch, and can coat | coat a coating layer uniformly at the thickness prescribed | regulated by this invention. As a sputtering method, a direct current magnetron sputtering method is mentioned.

(Manufacture of a printed wiring board)

The printed wiring board (PWB) can be manufactured according to a conventional method using the copper foil which concerns on this description. Below, the manufacture example of a printed wiring board is shown.

First, copper foil and an insulated substrate are bonded together and a copper clad laminated board is manufactured. The insulating substrate on which copper foil is laminated is not particularly limited as long as it has a property applicable to a printed wiring board. For example, a paper-based phenol resin, a paper-based epoxy resin, a synthetic fiber cloth-based epoxy resin, a glass cloth for a rigid PWB A polyester film, a polyimide film, etc. can be used for FPC, using a cloth, paper composite base material epoxy resin, a glass cloth, a glass nonwoven fabric composite base material epoxy resin, and a glass cloth base material epoxy resin.

When the bonding method is for a rigid PWB, a prepreg in which a resin such as a glass cloth is impregnated with a resin and cured to a semi-cured state is prepared. It can carry out by superposing the surface which has a prepreg and the coating layer of copper foil, and heat-pressing.

In the case of flexible printed wiring boards (FPC), the surface which has a coating layer of a polyimide film or a polyester film and copper foil can be adhere | attached using an epoxy type or an acrylic adhesive (3 layer structure). Moreover, as a method (two-layered structure) which does not use an adhesive agent, the casting method which apply | coats the polyimide varnish (polyamic acid varnish) which is a precursor of a polyimide to the surface which has a coating layer of copper foil, and imidates by heating, The lamination method which apply | coats a thermoplastic polyimide on a mid film, superimposes the surface which has a coating layer of copper foil on it, and heat-presses is mentioned. In the casting method, it is also effective to apply an anchor coat material such as thermoplastic polyimide in advance before applying the polyimide varnish.

The effect of the copper foil which concerns on this invention is remarkable when the FPC is manufactured using the casting method. That is, in order to adhere | attach copper foil and resin without using an adhesive agent, the adhesiveness of copper foil with respect to resin is especially required, Since the copper foil which concerns on this invention is excellent in adhesiveness with resin, especially polyimide, It can be said that it is suitable for manufacture of the copper clad laminated board by a law.

The copper clad laminated board which concerns on this invention can be used for various printed wiring boards (PWB), Although it does not restrict | limit especially, For example, it applies to single-sided PWB, double-sided PWB, multilayer PWB (3 or more layers) from a viewpoint of the number of layers of a conductor pattern. It can be applied to a rigid PWB, a flexible PWB (FPC), and a rigid flex PWB from the viewpoint of the type of insulating substrate material.

The process of manufacturing a printed wiring board from a copper clad laminated board may use the method well-known to those skilled in the art, For example, an etching resist is apply | coated to the copper foil surface of a copper clad laminated board only as a conductive pattern, and an unnecessary copper foil is sprayed by spraying an etching liquid on the copper foil surface. Can be removed to form a conductor pattern, and then the etching resist can be peeled and removed to expose the conductor pattern.

Example

Hereinafter, although the Example of this invention is shown, these are provided in order to understand this invention better, and it does not intend that this invention is limited.

(Example 1: Examples 1 to 44)

As the copper foil base materials of Examples 1-6 and 8-44, the rolled copper foil (Nico Metal Co., Ltd. product C1100) of thickness 18micrometer was prepared. The surface roughness (Rz) of the rolled copper foil was 0.7 µm. Moreover, the roughening process electrolytic copper foil of thickness 18micrometer was prepared as the copper foil base material of Example 7. The surface roughness (Rz) of the electrolytic copper foil was 1.5 µm.

Various single substances (a-e) used for sputtering used the thing of 3N purity. Moreover, various alloys (f-1) were manufactured in the following procedures. First, the element of the composition shown to Table 1 (alloy component [mass%] of a sputtering target) is added to electric copper or nickel, and the ingot was cast in the high frequency melting furnace, and it hot-rolled at 600-900 degreeC. Furthermore, after homogenizing annealing at 500-850 degreeC for 3 hours, the oxide layer of the surface layer was removed and it used as the target for sputtering.

About the single side | surface of this copper foil, the intermediate | middle layer and Cr layer are ordered by removing the thin oxide film previously adhering to the surface of copper foil base material on the following conditions with reverse sputter | spatter, and sputtering the target of a-1 and Cr monolayer. It was formed as it was. The thickness of the coating layer was changed by adjusting the film formation time.

Apparatus: Batch-type sputtering apparatus (R.D., type MNS-6000)

Reach Vacuum: 1.0 × 10 ^-5

Sputtering pressure: 0.2 kPa

Reverse sputter power: 100 W

Target:

  Intermediate layer = a to 1

  For Cr layer = Cr (purity 3 N)

Sputtering Power: 50 W

Film-forming speed: About 0.2 micrometer was formed into a film for each target for fixed time, the thickness was measured with the three-dimensional measuring instrument, and the sputter rate per unit time was computed.

The polyimide film was adhere | attached on the copper foil which formed the coating layer in the following procedures.

(1) Ube Hungsan-made U varnish-A (polyimide varnish) was apply | coated so that it might be 25 micrometers in a dry body using an applicator with respect to the copper foil of 7 cm * 7 cm.

(2) The copper foil with resin obtained by (1) was dried by air at 130 degreeC for 30 minutes in air.

(3) Imidization in 350 degreeC for 30 minutes in the high temperature heating furnace which set the nitrogen flow volume to 10 l / min.

Moreover, separately from the adhesion test of the said polyimide film, as a "heat resistance test", it heated at 350 degreeC for 2 hours as it is in nitrogen atmosphere, without sticking a polyimide film to the copper foil in which the coating layer was formed.

<Measurement of adhesion amount>

50 ㎜ × 50 ㎜ of the film of the copper foil surface was dissolved in a mixed solution of HNO ₃ (2 wt%) and HCl (5 wt%), firing the metal concentration in the solution ICP spectrometer (SI child, nano It was quantified by SFC-3100 manufactured by Technology Co., Ltd., and the amount of metal (μg / dm ² ) per unit area was calculated. In the present invention, the deposition amount of Cu and other metals when the Cu alloy is targeted, and the deposition amount of Cr and other metals when the Cr alloy is targeted are formed on the Ti foil under the same conditions. Analytical values were used.

<Measurement by XPS>

The operation conditions of XPS at the time of creating the depth profile of a coating layer are shown below.

Device: XPS Measuring Device (Albac Paisa, Type 5600MC)

Reach Vacuum: 3.8 × 10 ^-7 ㎩

X-ray: Monochrome AlKα or non-monochrome MgKα, X-ray output 300 W, detection area 800 μmφ, angle 45 ° between sample and detector

Ion line: Ion species Ar ⁺ , acceleration voltage 3 kW, sweep area 3 mm x 3 mm, sputtering rate 2.0 nm / min (SiO ₂ equivalent)

In the measurement result of XPS, separation of chromium oxide and metal chromium is carried out by Alk. 3. It was carried out using 1.

After the film formation by sputter | spatter, the conditions which performed heat processing (350 degreeC * 120 minutes) of severe conditions than the polyimide hardening conditions (350 degreeC * 30 minutes) at the time of adhesive strength analysis, and the film after peeling an insulating substrate were analyzed. .

<Measurement by TEM>

The measurement conditions of TEM when the coating layer was observed by TEM are shown below. The thickness shown in the table mentioned later measures the maximum value and minimum value of the thickness between 50 nm with respect to 1 view | sight for the thickness of the whole coating layer reflected in an observation visual field, and calculate | requires the maximum value and minimum value of the 3 visual fields chosen arbitrarily, The ratio of the minimum value to the maximum value was obtained as a percentage. In addition, after TEM observation result of "after a heat test" in a table | surface adhere | attaches a polyimide film on the coating layer of a test piece by the said procedure, it puts a test piece under the following high temperature environment, and peels a polyimide film 90 degrees from the obtained test piece. TEM image after peeling according to the method (JIS C 6471 8.1). In FIG. 1, the observation photograph after film-forming by TEM of Example 17 is shown by way of example. The middle cannot be confirmed from FIG. This is because the corresponding part is made of a copper alloy layer and is indistinguishable from the copper foil which is a base material. Confirmed in FIG. 1 is assumed to be a Cr layer. In the present invention, the thickness of only the layer having a clear boundary with the base metal was measured.

Device: TEM (Hitachi Corporation, Model H9000NAR)

Acceleration voltage: 300 ㎸

Magnification: 300000 times

Observation Field of View: 60 nm x 60 nm

<Adhesive evaluation>

About copper foil which laminated | stacked the polyimide as mentioned above, after peeling a peeling strength (state) immediately after lamination for 168 hours in the high temperature environment under 150 degreeC of air atmosphere (heat resistance), and 40 degreeC of temperature, 95% of relative humidity. It was measured under three conditions of (moisture resistance) after being left for 96 hours in a high humidity environment under an air atmosphere. Peel strength was measured according to the 90 ° peeling method (JIS C 6471 8.1).

Etchability Evaluation

The white tape was affixed on the coating layer of the copper foil manufactured as mentioned above, and it immersed for 7 minutes in etching liquid (copper chloride dihydrate, ammonium chloride, ammonia water, liquid temperature of 50 degreeC). Then, the metal component of the etching residue adhered to the tape was quantified by the ICP emission spectroscopy apparatus, and the following references | standards evaluated.

X: etching residue is 140 µg / dm ² or more

(Triangle | delta): An etching residue is 70 microgram / dm <^2> or more and less than 140 microgram / dm <^2> .

(Circle): Etch residue is less than 70 microgram / dm <^2> .

(Example 2: Comparative Examples 1 to 28)

Sputtering time was changed to the single side | surface of the rolled copper foil base material used in Example 1, and the film of the thickness of the table | surface mentioned later was formed. The polyimide film was adhere | attached on the copper foil which formed the coating layer in the same procedure as Example 1.

(Example 3: Comparative Example 29)

On one side of the rolled copper foil base material used in Example 1, Ni-Zn plating treatment, chromate treatment, and silane coupling agent treatment taught in JP-A-2005-344174 were performed under the following conditions, respectively.

(Ni-Zn plating treatment)

Nickel Sulfate 1.5 g / L (Ni equivalent)

Zinc pyrophosphate 0.5 g / l (Zn equivalent)

200 g / l potassium pyrrole phosphate

PH 9

Bath temperature 40 ℃

Current density 5 A / dm ²

[Chromate processing]

CrO ₃ 1 g / ℓ

Bath temperature 35 ° C

Current density 8 A / dm ²

[Silane coupling agent treatment]

5 g / L solution of γ-aminopropyltriethoxysilane

(Example 4: Comparative Example 30)

On one side of the rolled copper foil base material used in Example 1, Ni plating treatment, chromate treatment, and silane coupling agent treatment taught in JP-A-2007-007937 were performed under the following conditions, respectively.

[Ni plating process]

_{· NiSO 4 / 7H 2 O 300} g / ℓ ( as by Ni ^{+ 2)}

H ₃ BO ₃ 40 g / ℓ

Bath temperature 25 ℃

Current density 1.0 A / dm ²

[Chromate processing]

CrO ₃ 1 g / ℓ

Bath temperature 25 ℃

Current density 2.0 A / dm ²

[Silane coupling agent treatment]

Apply 0.3% solution of 3-aminopropyltriethoxysilane

Each measurement result of Examples 1-4 is shown to Tables 2-7.

Examples 1-3 and 6-44 all have favorable peel strength and etching property. In addition, although Examples 4 and 5 had a little inferior etching property compared with the Example mentioned above, peeling strength was favorable.

Moreover, the depth profile by XPS of the copper foil (after heat processing corresponded to polyimide varnish hardening) of Example 17 is shown in FIG. In the Cr layer, an oxide Cr layer exists in the surface layer, and a layer of metal Cr exists immediately below it. Since the distances from the surface layer in which the concentrations of the oxides Cr and the metal Cr are maximum are different from each other, it can be said that both are separated into two layers. Within the range of 1 nm from the surface layer, unlike electroplating, the atomic concentration ratio of the oxide Cr exceeded 20%. In other examples, the atomic concentration ratio of the oxide Cr was in excess of 20% in the vicinity of the surface layer. Moreover, also in any Example, the diffusion of Cu atom to the surface layer was not confirmed. It is assumed that this is an effect of forming an intermediate layer for preventing diffusion of Cu atoms directly under the Cr layer.

In Comparative Example 1, the coating amount of Cr was less than 18 µg / dm ² , and the peel strength was poor.

Comparative Example 2 is the coating amount of Cr 180 ㎍ / dm ² It was excess and the etching property was bad.

In Comparative Examples 3 to 28, the coating amount of Cr was in the range of 18 to 180 µg / dm ² , but various peeling strength or etching properties were poor due to the coating amount related to various elements used in the intermediate layer.

In Comparative Examples 29 and 30, the heat resistance and the moisture resistant peel strength were poor, respectively. It is presumed that the amount of trivalent Cr in the range of 0-1 nm was small from the surface layer from the depth profile by XPS of the copper foil of the comparative examples 20 and 30 shown to FIG. 3 and 4.

Claims (21)

As a copper foil for printed wiring boards which provided the copper foil base material and the coating layer which coat | covers at least one part of the copper foil base material surface,
The coating layer consists of an intermediate | middle layer which consists of a single metal, or an alloy, and a Cr layer laminated | stacked in order from the copper foil base material surface,
Cr is present in the coating layer at a coating amount of 18 to 180 µg / dm ² ,
The atomic concentration (%) of the metal chromium in the depth direction (x: unit nm) obtained from the depth direction analysis from the surface by XPS is set to f ₁ (x), and the atomic concentration (%) of the oxide chromium is f ₂ (x). ), The atomic concentration (%) of all chromium is f (x), (f (x) = f ₁ (x) + f ₂ (x)), and the atomic concentration (%) of nickel is g (x). The atomic concentration (%) of copper is h (x), the atomic concentration (%) of oxygen is i (x), the atomic concentration (%) of carbon is j (x), and other metals. If the sum of the atomic concentrations of is k (x), then 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 10% or less, and ∫f ₂ (x) dx / (∫f (x) dx + ∫g (x) dx + ∫h (x) dx + ∫ i (x) dx + ∫j (x) dx + ∫k (x) dx) is 20% or more, and is 0.1 in the interval [1.0, 2.5].

∫f ₁ (x) dx / ∫f ₂ (x) dx

Copper foil for printed wiring boards satisfying 1.0. The copper foil for printed wiring boards of Claim 1 in which Cr exists in the coating amount of 30-145 microgram / dm <^2> . The copper foil for printed wiring boards of Claim 2 in which Cr exists in the coating amount of 36-90 microgram / dm <^2> . The copper foil for printed wiring boards of Claim 3 in which Cr exists in the coating amount of 36-75 microgram / dm <^2> . The copper foil for printed wiring boards of any one of Claims 1-4 in which an intermediate | middle layer contains at least any 1 type of Ni, Mo, Ti, Zn, Co, V, Sn, Mn, and Cr. The coating layer is comprised from the intermediate | middle layer consisting of any 1 type of Ni, Mo, Ti, Zn, and Co laminated in order from the surface of copper foil base material, and Cr layer, The intermediate | middle layer contains Ni, Mo, Copper foil for printed wiring boards in which any one of Ti, Zn, and Co exists in the coverage of 15-1030 microgram / dm <^2> . The method of claim 6, wherein the intermediate layer is, Ni is ^{15 ~ 440 ㎍ / dm 2,} Mo is ^{25 ~ 1030 ㎍ / dm 2,} Ti is ^{15 ~ 140 ㎍ / dm 2,} Zn is 15 ~ 750 ㎍ / dm ^2, or Copper foil for printed wiring boards which Co exists in the coating amount of 25-1030 microgram / dm <^2> . The coating layer is composed of an intermediate layer composed of at least any two alloys of Ni, Zn, V, Sn, Mn, Cr, and Cu, and a Cr layer, which are laminated in order from the surface of the copper foil base material. Copper foil for printed wiring boards which two or more of Ni, Zn, V, Sn, Mn, and Cr exist in an intermediate | middle layer in 20-1700 microgram / dm <^2> of coating amounts. The copper foil for printed wiring boards of Claim 8 in which an intermediate | middle layer consists of Ni and Ni alloy which consists of any 1 type of Zn, V, Sn, Mn, and Cr. The Ni-Zn alloy according to claim 9, wherein the intermediate layer is made of Ni having a coating amount of 15 to 1000 µg / dm ² and Zn having 5 to 750 µg / dm ² , Ni having a total coating amount of 20 to 600 µg / dm ² , and Ni-V alloy consisting of V, Ni-Sn alloy consisting of Ni and Sn having a total coating amount of 18 to 450 µg / dm ² , Ni having a coating amount of 15 to 450 µg / dm ² , and Mn of 5 to 200 µg / dm ² Copper foil for printed wiring boards which consists of a Ni-Mn alloy which consists of Ni, the Ni-Cr alloy which consists of Ni whose coverage is 20-440 microgram / dm <^2> , and Cr which is 5-110 microgram / dm <^2> . The copper foil for printed wiring boards of Claim 8 in which an intermediate | middle layer consists of Cu and Cu alloy which consists of any 1 type or 2 types of Zn and Ni. The Cu-Zn alloy having a coating amount of Zn of 15 to 750 µg / dm ² , the Cu-Ni alloy having a Ni coating amount of 15 to 440 µg / dm ² , or the Ni coating amount of 15 to 1000 µg according to claim 11. / dm ² Copper foil for printed wiring boards which consists of Cu-Ni-Zn alloy whose Zn coating amount is 5-750 microgram / dm <^2> . The copper foil for printed wiring boards of any one of Claims 1-12 whose maximum thickness is 0.5-12 nm and the minimum thickness is 80% or more of the maximum thickness, when the cross section of a coating layer is observed with a transmission electron microscope. The atom of the metal chromium in the depth direction (x: unit nm) obtained from the depth direction analysis from the surface by XPS, when performing heat processing corresponded to polyimide hardening in any one of Claims 1-13. Let concentration (%) be f ₁ (x), atomic concentration (%) of oxide chromium be f ₂ (x), atomic concentration (%) of all chromium be f (x) (f (x) = f ₁ (x) + f ₂ (x)), the atomic concentration (%) of nickel is g (x), the atomic concentration (%) of copper is h (x), and the atomic concentration (%) of oxygen Is i (x), the atomic concentration (%) of carbon is j (x), and the sum of the atomic concentrations of other metals is k (x), ∫h ( x) dx / (∫f (x) dx + ∫g (x) dx + ∫h (x) dx + ∫i (x) dx + ∫j (x) dx + ∫k (x) dx) is 10% or less, and ∫f ₂ (x) dx / (∫f (x) dx + ∫g (x) dx + ∫h (x) dx + ∫i (x) dx + ∫j (x) dx + ∫k (x) dx) is 20% or more, In the interval [1.0, 2.5] 0.1

∫f ₁ (x) dx / ∫f ₂ (x) dx

Copper foil for printed wiring boards satisfying 1.0. The copper foil for printed wiring boards in which heat processing corresponded to polyimide hardening was given, The depth direction (x: unit nm) obtained from the depth direction analysis from the surface by XPS. The atomic concentration (%) of metal chromium is f ₁ (x), the atomic concentration (%) of oxide chromium is f ₂ (x), and the atomic concentration (%) of all chromium is f (x) ( f (x) = f ₁ (x) + f ₂ (x)), the atomic concentration (%) of nickel is g (x), the atomic concentration (%) of copper is h (x), and the atom of oxygen If the concentration (%) is i (x), the atomic concentration (%) of carbon is j (x), and the sum of the atomic concentrations of other metals 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 10% or less ∫f ₂ (x) dx / (∫f (x) dx + ∫g (x) dx + ∫h (x) dx + ∫i (x) dx + ∫j (x) dx + ∫k (x) dx) is 20 % Or more , 0.1 in the interval [1.0, 2.5]

∫f ₁ (x) dx / ∫f ₂ (x) dx

Copper foil for printed wiring boards satisfying 1.0. The copper foil for printed wiring boards in which the insulated substrate was formed through the coating layer, and when the surface of the coating layer after peeling an insulating substrate from the coating layer was analyzed from the surface by XPS in any one of Claims 1-15. The atomic concentration (%) of the metal chromium in the depth direction (x: unit nm) obtained from the depth direction analysis of is set to f ₁ (x), and the atomic concentration (%) of the oxide chromium is set to f ₂ (x), The atomic concentration (%) of chromium is f (x) (f (x) = f ₁ (x) + f ₂ (x)), the atomic concentration (%) of nickel is g (x), and the atom of copper The concentration (%) is h (x), the atomic concentration (%) of oxygen is i (x), the atomic concentration (%) of carbon is j (x), and the sum of the atomic concentrations of other metals. Is k (x) and the distance from the surface layer where the concentration of the metal chromium is maximum is F, 0.1 in the interval [O, F].

∫f ₁ (x) dx / ∫f ₂ (x) dx

1.0 and ∫h (x) dx / (∫f (x) dx + ∫g (x) dx + ∫h (x) dx + ∫i (x) dx + ∫j (x) dx + ∫k (x) dx) is 10 Copper foil for printed wiring boards which satisfy | fills% or less. The copper foil for printed wiring boards of any one of Claims 1-16 whose copper foil base material is a rolled copper foil. The copper foil for printed wiring boards of any one of Claims 1-17 whose printed wiring board is a flexible printed wiring board. The copper clad laminated board provided with the copper foil in any one of Claims 1-18. The copper clad laminate according to claim 19, wherein the copper foil has a structure in which the copper foil is bonded to the polyimide. The printed wiring board which used the copper clad laminated board of Claim 19 or 20 as a material.

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