JP2024077031A - Treatment liquid and laminate - Google Patents

Abstract

[Problem] To provide a treatment liquid capable of producing wiring with excellent wiring drawability and excellent electrical conductivity, and a laminate using the treatment liquid. [Solution] The treatment liquid of the present invention is a treatment liquid for forming a surface modified layer to be interposed between a copper plate and a resin layer, which contains a nitrogen-containing heterocyclic compound, the content of the nitrogen-containing heterocyclic compound being within the range of 1 to 1000 mass ppm, and the content ratio of nitrogen atoms to copper atoms measured by X-ray photoelectron spectroscopy (XPS) of the surface of the copper plate after the treatment liquid is applied to the copper plate and washed with water is within the range of 1 to 80%, and the content ratio of nitrogen atoms to copper atoms measured by X-ray photoelectron spectroscopy of the surface of the copper plate after the washing with water and after washing with an alkaline aqueous solution having a pH of 7 or more converted at 25°C is 55% or less. Furthermore, the content ratio of nitrogen atoms to copper atoms after washing with the alkaline aqueous solution is 95% or less of the content ratio of nitrogen atoms to copper atoms after the washing with water. [Selected Figure] Figure 1

Description

The present invention relates to a treatment liquid and a laminate, and in particular to a treatment liquid that has excellent wiring drawability and can produce wiring with excellent conductivity.

2. Description of the Related Art In recent years, with the advancement of the data society, there is a demand for printed wiring boards (also called "printed circuit boards") with high density and high definition wiring.
In the manufacturing process of a printed wiring board, a resin material such as an etching resist, a plating resist, a solder resist, a prepreg, etc. is bonded to the surface of a metal layer or a metal wiring. In the manufacturing process of a printed wiring board and in the product after the manufacturing, high adhesion is required between the metal layer and the resin layer.

Therefore, in order to increase the adhesion between the metal layer and the resin layer, a method is known in which a coating for improving adhesion between the metal layer and the resin layer is formed on the surface of the metal layer (see, for example, Patent Document 1). Also, a method is known in which a sulfur-containing compound and a nitrogen-containing compound (a compound containing a nitrogen-containing aromatic heterocycle) are incorporated into a photosensitive resin to increase adhesion (see, for example, Patent Document 2).

However, when a reagent containing a nitrogen-containing heterocycle as described above is applied to the surface of a metal such as a copper plate, the following problems arise.
(a) In the copper wiring etching step after applying a reagent containing a nitrogen-containing heterocycle and adhering a resin layer, if a certain amount of the nitrogen-containing heterocyclic compound remains, it adversely affects the drawing properties of the copper wiring.
(b) If the nitrogen-containing heterocyclic compound remains on the surface of the copper plate to a certain extent after the step of peeling off the resin layer, it adversely affects the electrical conductivity of the final product.
(c) If the nitrogen-containing heterocyclic compound penetrates into the copper plate after the reagent is applied to the surface of the copper plate, it will adversely affect the resistance, drawability and conductivity of the wiring thus produced.

JP 2017-203073 A JP 2020-34933 A

The present invention was made in consideration of the above problems and circumstances, and the problem to be solved is to provide a treatment liquid that has excellent wiring drawability and can produce wiring with excellent conductivity. Also, the present invention is to provide a laminate using the treatment liquid.

In the course of investigating the causes of the above problems in order to solve the above problems, the present inventors have found the following. It is important to set the content of the nitrogen-containing heterocyclic compound within a specific range, and to set the content ratio of nitrogen atoms to copper atoms on the copper plate surface after applying a treatment solution and rinsing with water, and the content ratio of the nitrogen atoms after rinsing with an alkaline aqueous solution, within specific ranges. Furthermore, it has been found that it is also important to make the content ratio of the nitrogen atoms after rinsing with an alkaline aqueous solution smaller than the content ratio of the nitrogen atoms after rinsing with water. This makes it possible to produce wiring that has excellent wiring drawability and excellent conductivity.
That is, the above-mentioned problems of the present invention are solved by the following means.

1. A treatment solution for forming a surface modification layer to be interposed between a copper plate and a resin layer,
Contains a nitrogen-containing heterocyclic compound,
The content of the nitrogen-containing heterocyclic compound is within the range of 1 to 1000 ppm by mass, and
the content ratio of nitrogen atoms to copper atoms of the copper plate measured by X-ray photoelectron spectroscopy (XPS) after the copper plate is applied and washed with water is within a range of 1 to 80%;
After the water washing and after cleaning with an alkaline aqueous solution having a pH of 7 or more converted at 25°C, the content ratio of nitrogen atoms to copper atoms measured by X-ray photoelectron spectroscopy (XPS) on the surface of the copper plate is 55% or less, and
a content ratio of nitrogen atoms to copper atoms, as measured by X-ray photoelectron spectroscopy (XPS) of the surface of the copper plate after cleaning with the alkaline aqueous solution, is 95% or less of a content ratio of nitrogen atoms to copper atoms, as measured by X-ray photoelectron spectroscopy (XPS) of the surface of the copper plate after rinsing with water.

2. The nitrogen-containing heterocyclic compound is a compound having a nitrogen-containing heterocycle and a functional group containing a nitrogen atom or an oxygen atom,
2. The treatment solution according to item 1, wherein the number of nitrogen atoms in the nitrogen-containing heterocycle is 2 to 4, and at least one of the nitrogen atoms is NH.

3. The treatment liquid according to item 2, wherein the functional group is any one of --COOH, --NH ₂ , --OH, --NHR and --NR ₂ , where R represents an alkyl group.

［式中、Ｗ_１～Ｗ_７は、炭素原子又は窒素原子を表し、Ｗ_１～Ｗ_７のうち２～４個が窒素原子を表し、少なくとも１つがＮＨを表す。
Ｙ_１～Ｙ_５は、炭素原子又は窒素原子を表し、Ｙ_１～Ｙ_５のうち２～４個が窒素原子を表し、少なくとも１つがＮＨを表す。
Ｚ_１は、－ＣＯＯＨ、－ＮＨ_２、－ＯＨ、－ＮＨＲ又は－ＮＲ_２を表す。Ｚ_２は、－ＣＯＯＨ、－ＯＨ、－ＮＨＲ又は－ＮＲ_２を表し、Ｒは、アルキル基を表す。
Ｌは、単結合、連結基表す。］ 4. The treatment liquid according to item 1, wherein the nitrogen-containing heterocyclic compound has a structure represented by the following general formula 1 or 2:

[In the formula, W ₁ to W ₇ represent a carbon atom or a nitrogen atom, two to four of W ₁ to W ₇ represent nitrogen atoms, and at least one represents NH.
Y ₁ to Y ₅ each represent a carbon atom or a nitrogen atom, and two to four of Y ₁ to Y ₅ represent nitrogen atoms, and at least one represents NH.
Z ₁ represents -COOH, -NH ₂ , -OH, -NHR or -NR _2. Z ₂ represents -COOH, -OH, -NHR or -NR ₂ , where R represents an alkyl group.
L represents a single bond or a linking group.

5. The treatment liquid according to item 1, which contains at least water or an alcohol.

6. The ratio of nitrogen atoms to copper atoms on the surface of the copper plate after the water washing is within the range of 5 to 65%, as measured by X-ray photoelectron spectroscopy (XPS); and
2. The treatment solution according to claim 1, wherein a content ratio of nitrogen atoms to copper atoms of the surface of the copper plate after cleaning with the alkaline aqueous solution is within a range of 0 to 35%, as measured by X-ray photoelectron spectroscopy (XPS).

7. The treatment solution according to item 1, wherein a content ratio of nitrogen atoms to copper atoms, as measured by X-ray photoelectron spectroscopy (XPS) on the surface of the copper plate after cleaning with the alkaline aqueous solution, is 85% or less of a content ratio of nitrogen atoms to copper atoms, as measured by X-ray photoelectron spectroscopy (XPS) on the surface of the copper plate after rinsing with water.

8. The treatment liquid according to item 1, wherein the content of the nitrogen-containing heterocyclic compound is within a range of 1 to 200 ppm by mass.

9. A laminate in which a surface modification layer and a resin layer are sequentially provided on a copper plate,
9. A laminate, wherein the surface modification layer is made of the treatment liquid according to any one of items 1 to 8.

According to the above-mentioned means of the present invention, it is possible to provide a treatment liquid capable of producing wiring having excellent wiring drawability and excellent electrical conductivity, and also to provide a laminate using the treatment liquid.
Although the mechanism by which the effects of the present invention are manifested or the mechanism by which the effects of the present invention are acted upon has not been clarified, it is speculated as follows.

In the wiring etching process for the copper plate after the resin layer has been formed, if a certain amount of nitrogen-containing heterocyclic compounds remain on the copper plate surface, it will hinder uniform etching and adversely affect the drawing properties of the wiring. Therefore, it is necessary to apply a treatment solution to the copper plate surface, rinse with water, and then reduce the amount of nitrogen-containing heterocyclic compounds on the copper plate surface to a certain amount or less. Therefore, the nitrogen atom content ratio to copper atoms, as measured by X-ray photoelectron spectroscopy (XPS) on the copper plate surface after the treatment solution is applied to the copper plate and rinsed with water, is set to a range of 1 to 80%.

In addition, if a certain amount of nitrogen-containing heterocyclic compounds remain on the copper plate surface after the resin layer peeling process using an alkaline aqueous solution, it will impair the uniformity of the resistance value of the produced wiring. As a result, it will have a negative effect on the conductivity of the final product, so it is necessary to keep the amount of nitrogen-containing heterocyclic compounds on the copper plate surface after washing with an alkaline aqueous solution below a certain amount. Therefore, the nitrogen atom content ratio to copper atoms measured by X-ray photoelectron spectroscopy (XPS) on the surface of the copper plate after applying the solution to the copper plate and washing with an alkaline aqueous solution of pH 7 or higher is set to 55% or less.

Furthermore, the content of the nitrogen-containing heterocyclic compound in the treatment liquid applied to the copper plate surface in the board wiring process does not increase. Therefore, if the ratio of nitrogen atoms to copper atoms after the water washing exceeds the ratio of nitrogen atoms to copper atoms after the alkaline aqueous solution washing, there is a possibility that the nitrogen-containing heterocyclic compound has penetrated into the copper plate. If the nitrogen-containing heterocyclic compound penetrates into the copper plate in this way, it will have an adverse effect on the drawability and conductivity of the wiring produced. Therefore, the content of the nitrogen-containing aromatic heterocyclic compound is set to a range of 1 to 1000 ppm by mass, and the content ratio of the nitrogen atoms after the alkaline aqueous solution washing is set to 95% or less of the content ratio of the nitrogen atoms after the water washing.

FIG. 1 is a schematic diagram showing the coordination state between a nitrogen atom present in the structure of a nitrogen-containing heterocyclic compound according to the present invention and an alkylamino group, which is a functional group. FIG. 1 is a diagram for explaining the orientation of a nitrogen-containing heterocyclic compound according to the present invention. Diagram showing the metal wiring pattern formation process (copper plate cleaning) A diagram showing the process of forming a metal wiring pattern (forming a surface modification layer) A diagram showing the process of forming a metal wiring pattern (forming a resist layer) A diagram showing the process of forming a metal wiring pattern (patterning of the resist layer) A diagram showing the process of forming a metal wiring pattern (etching of the surface modification layer and copper plate) A diagram showing the process of forming a metal wiring pattern (peeling off the resist layer)

The treatment liquid of the present invention is a treatment liquid for forming a surface modified layer to be interposed between a copper plate and a resin layer, comprising a nitrogen-containing heterocyclic compound, the content of the nitrogen-containing heterocyclic compound being within the range of 1 to 1000 mass ppm, and the treatment liquid is applied to the copper plate, and the content ratio of nitrogen atoms to copper atoms measured by X-ray photoelectron spectroscopy (XPS) of the surface of the copper plate after washing with water is within the range of 1 to 80%, and the content ratio of nitrogen atoms to copper atoms measured by X-ray photoelectron spectroscopy (XPS) of the surface of the copper plate after washing with water and after washing with an alkaline aqueous solution having a pH of 7 or more converted at 25 ° C. is 55% or less, and the content ratio of nitrogen atoms to copper atoms measured by X-ray photoelectron spectroscopy (XPS) of the surface of the copper plate after washing with the alkaline aqueous solution is 95% or less of the content ratio of nitrogen atoms to copper atoms measured by X-ray photoelectron spectroscopy (XPS) of the surface of the copper plate after washing with water.
This feature is a technical feature common to or corresponding to each of the following embodiments.

In one embodiment of the present invention, the nitrogen-containing heterocyclic compound is a compound having both a nitrogen-containing heterocycle and a functional group containing a nitrogen atom or an oxygen atom, and the number of nitrogen atoms in the nitrogen-containing heterocycle is preferably 2 to 4, at least one of which is NH. This allows the N atom of the NH to interact with Cu in the copper plate, forming a coordinate bond and improving adhesion to the copper plate.

It is preferable that the functional group is any one of -COOH, -NH ₂ , -OH, -NHR or -NR ₂ , with R representing an alkyl group. This allows the functional group to form a hydrogen bond or an ionic bond with a polar group present in the resin. As a result, the copper plate can adhere to the resin layer with an interaction force stronger than π-π interaction or van der Waals force. In addition, since the specific functional group is a water-soluble functional group, it is easy to control the content ratio of the nitrogen atoms on the copper plate surface after washing with water within the range of the present invention. As a result, this leads to improved adhesion between the copper plate and the resin layer.
In particular, it is preferable that the nitrogen-containing heterocyclic compound has a structure represented by the general formula 1 or 2, since the compound is water-soluble and easily soluble in an alkaline aqueous solution, and therefore the content ratio of the nitrogen atoms on the copper plate surface after washing with water and cleaning with an alkaline aqueous solution can be easily controlled within the range of the present invention.

It is preferable that the ratio of nitrogen atoms to copper atoms measured by X-ray photoelectron spectroscopy (XPS) on the surface of the copper plate after the water washing is within a range of 5 to 65%, and that the ratio of nitrogen atoms to copper atoms measured by X-ray photoelectron spectroscopy (XPS) on the surface of the copper plate after the alkaline aqueous solution washing is within a range of 0 to 35%. This results in excellent wiring drawability, improved uniformity in the resistance value of the produced wiring, and excellent conductivity of the final product.

The ratio of nitrogen atoms to copper atoms measured by X-ray photoelectron spectroscopy (XPS) on the surface of the copper plate after washing with the alkaline aqueous solution is preferably 85% or less of the ratio of nitrogen atoms to copper atoms measured by X-ray photoelectron spectroscopy (XPS) on the surface of the copper plate after washing with water. This confirms that the nitrogen-containing heterocyclic compound has not penetrated into the interior of the copper plate. This makes it possible to suppress adverse effects on the drawability and conductivity of the produced wiring, and ensures high wiring performance.

When the content of the nitrogen-containing heterocyclic compound is within the range of 1 to 200 ppm by mass, the nitrogen-containing heterocyclic compound does not adhere too much to the copper plate surface, and can be appropriately washed away by washing with water and an alkaline aqueous solution. Therefore, the content ratio of the nitrogen atoms on the copper plate surface can be controlled within the range of the present invention. As a result, the adhesion between the copper plate and the resin layer is further improved.

The laminate of the present invention is a laminate in which a surface modification layer and a resin layer are sequentially provided on a copper plate, and the surface modification layer is made of the treatment liquid. This allows for a laminate with wiring that is excellent in drawing properties and has excellent electrical conductivity.

The present invention, its components, and the form and mode for implementing the present invention are described below. Note that in this application, "~" is used to mean that the numerical values before and after it are included as the lower and upper limits.

[Treatment solution of the present invention]
The treatment liquid of the present invention is a treatment liquid for forming a surface modified layer to be interposed between a copper plate and a resin layer, comprising a nitrogen-containing heterocyclic compound, the content of the nitrogen-containing heterocyclic compound being within the range of 1 to 1000 mass ppm, and the treatment liquid is applied to the copper plate, and the content ratio of nitrogen atoms to copper atoms measured by X-ray photoelectron spectroscopy (XPS) of the surface of the copper plate after washing with water is within the range of 1 to 80%, and the content ratio of nitrogen atoms to copper atoms measured by X-ray photoelectron spectroscopy (XPS) of the surface of the copper plate after washing with water and after washing with an alkaline aqueous solution having a pH of 7 or more converted at 25 ° C. is 55% or less, and the content ratio of nitrogen atoms to copper atoms measured by X-ray photoelectron spectroscopy (XPS) of the surface of the copper plate after washing with the alkaline aqueous solution is 95% or less of the content ratio of nitrogen atoms to copper atoms measured by X-ray photoelectron spectroscopy (XPS) of the surface of the copper plate after washing with water.

The "treatment liquid" in the present invention refers to a liquid prepared by adding a nitrogen-containing heterocyclic compound for forming a surface modification layer to a solvent or the like.
In the present invention, the "treatment liquid" refers to a treatment liquid in which, under normal conditions, the nitrogen-containing heterocyclic compound absorbs light and the bonds within the molecule are not cleaved or the molecules are not polymerized together in a process for forming a surface modification layer, etc.

The treatment liquid of the present invention has a content of the nitrogen-containing heterocyclic compound in the range of 1 to 1000 ppm by mass based on the entire treatment liquid. The content is preferably in the range of 1 to 200 ppm by mass. When the content is in the range of 1 to 1000 ppm by mass, the nitrogen-containing heterocyclic compound does not adhere too much to the copper plate surface, and can be appropriately washed away by washing with water and an alkaline aqueous solution. Therefore, the content ratio of the nitrogen atoms on the copper plate surface can be controlled within the range of the present invention. As a result, the adhesion between the copper plate and the resin layer is further improved.
In addition to the adhesion, the nitrogen-containing heterocyclic compound can be appropriately washed away with an alkaline aqueous solution, improving the quality (conductivity) of the finished product.

<Ratio of Nitrogen Atoms to Copper Atoms Measured by X-ray Photoelectron Spectroscopy>
The treatment solution of the present invention is applied to a copper plate, and the surface of the copper plate after washing with water has a nitrogen atom content ratio (hereinafter also referred to as "X") relative to copper atoms in the range of 1 to 80%, as measured by X-ray photoelectron spectroscopy (XPS). The content ratio is more preferably in the range of 5 to 65%. When the content ratio is in the range of 1 to 80%, the amount of nitrogen-containing heterocyclic compound remaining on the copper plate surface can be minimized in the wiring etching step of the copper plate after the resin layer is formed. As a result, uniform etching is possible, and wiring drawing ability is excellent.

In addition, the treatment solution of the present invention has a nitrogen atom content ratio (hereinafter also referred to as "Y") to copper atoms of 55% or less, measured by X-ray photoelectron spectroscopy (XPS) on the surface of the copper plate after the water washing and after cleaning with an alkaline aqueous solution having a pH of 7 or more converted at 25°C. The content ratio is preferably within the range of 0 to 35%. When the content ratio is 55% or less, the amount of nitrogen-containing heterocyclic compounds remaining on the copper plate surface after the resin layer peeling process using an alkaline aqueous solution can be minimized. As a result, the electrical conductivity of the final product is good.

The ratio (%) of nitrogen atoms to copper atoms can be measured by X-ray photoelectron spectroscopy (hereinafter also referred to as XPS) and is a value expressed as (N atoms (atomic %) / Cu atoms (atomic %) x 100)%.

The XPS measurement conditions are as follows.
XPS measurement device: Quantera SXM (manufactured by ULVAC-PHI, Inc.)
X-ray source: monochromatic Al-Kα radiation, 100 μm, 25 W, 15 kV
Signal extraction angle: 45 degrees Analysis area: 500 μm x 500 μm
As a measurement method, first, a wide scan measurement was performed in the binding energy range from -20 eV to 1270 eV with a pass energy of 224 eV to determine what elements were detected.
Next, narrow scan measurements were performed on all the detected elements at a pass energy of 140 eV. Note that the wide scan and narrow scan were performed at different positions on the same sample.
As a quantification method, the surface element composition was quantified using analysis software MultiPak manufactured by ULVAC-PHI, Inc. The background of the spectrum of each element was obtained by the Shirley method for elements other than copper and the linear method for copper, and the surface element composition was obtained from the obtained peak area using the relative sensitivity coefficient method.
Then, from the obtained elemental composition, the content ratio of nitrogen atoms to copper atoms (N atoms (atomic %)/Cu atoms (atomic %)×100)%) was calculated.

The following methods can be used to adjust the nitrogen atom content ratio X to copper atom content on the surface of the copper plate after applying the treatment solution to the copper plate and rinsing with water to within the range of 1 to 80%.
(i) A specific nitrogen-containing heterocyclic compound described later is used.
(ii) The content of the nitrogen-containing heterocyclic compound is adjusted. Specifically, the content is adjusted to within the range of 1 to 1,000 ppm by mass, and preferably within the range of 1 to 200 ppm by mass.
If the concentration is within the range of 1 to 1000 ppm by mass, the nitrogen-containing heterocyclic compound does not adhere too much to the copper plate, and can be easily washed away by water.

(iii) Adjusting the water temperature during washing. Specifically, the water temperature is preferably within the range of 15 to 45° C., and more preferably within the range of 20 to 30° C. If the water temperature is within the range of 15 to 45° C., the nitrogen-containing heterocyclic compound will not remain too much on the copper plate surface after washing due to the water temperature being too low, and the nitrogen-containing heterocyclic compound will not be washed away too much due to high temperature.
(iv) After the treatment solution is applied to the copper plate, the time until washing with water is adjusted. Specifically, the time is preferably 500 hours or less, and more preferably 200 hours or less. By setting the time to 500 hours or less, it is possible to prevent the effective ingredient from deteriorating due to the time until washing with water being too long, and thus preventing the necessary amount of the effective ingredient from remaining after washing with water.

(v) Adjusting the magnesium ion concentration in the treatment solution. Specifically, the magnesium ion concentration is preferably 5 ppm by mass or less, more preferably 4 ppm by mass or less. By adjusting the magnesium ion concentration to 5 ppm by mass or less, it is possible to prevent the magnesium ions from reacting with the active ingredient and inhibiting the bond with copper due to an excessive amount of magnesium ions.
(vi) Adjusting the pH of the treatment solution. Specifically, the pH is preferably within the range of 5 to 10 at 25° C. If the pH is within this range, the active ingredients in the treatment solution are not affected and the bond with copper is not inhibited.

(vii) Adjust the sulfide ion concentration in the treatment solution. Specifically, it is preferable to set the sulfide ion concentration to 5 ppm by mass or less. By setting the sulfide ion concentration to 5 ppm by mass or less, it is possible to prevent an excessive amount of sulfide ions from reacting with the active ingredient and inhibiting the binding with copper.

In addition, the means for applying the treatment liquid to a copper plate and setting the nitrogen atom content ratio Y to copper atoms on the surface of the copper plate after washing with the alkaline aqueous solution to 55% or less include (i), (ii), and (v) to (vii) as described above for controlling the nitrogen atom content ratio after washing with water. Other examples include the following means.

(viii) Adjusting the temperature of the alkaline aqueous solution during washing. Specifically, the temperature of the solution is preferably within the range of 25 to 70° C., more preferably within the range of 35 to 60° C. If the temperature of the solution is within the range of 25 to 70° C., the nitrogen-containing heterocyclic compound will not remain excessively on the copper plate surface after washing due to an excessively low water temperature, and the nitrogen-containing heterocyclic compound will not remain on the copper plate surface due to a high temperature, causing redeposition.
(iX) The time from washing with water of the treatment solution to application of the alkaline aqueous solution is adjusted. Specifically, the time is preferably 500 hours or less, and more preferably 100 hours or less. By setting the time to 500 hours or less, it is possible to prevent the effective ingredient from deteriorating due to the time until alkaline washing being too long, and the nitrogen-containing heterocyclic compound from becoming difficult to wash off by alkaline washing.

Furthermore, the content ratio Y (%) of nitrogen atoms to copper atoms, measured by X-ray photoelectron spectroscopy (XPS) on the surface of the copper plate after cleaning with the alkaline aqueous solution, is 95% or less of the content ratio X of nitrogen atoms to copper atoms, measured by X-ray photoelectron spectroscopy (XPS) on the surface of the copper plate after washing with water. In other words, the value of "(Y/X)×100(%)" is 95% or less.
The value of "(Y/X) x 100(%)" is more preferably 85% or less, and the smaller the nitrogen atom content ratio Y after washing with an alkaline aqueous solution, the more preferable. This confirms that the nitrogen-containing heterocyclic compound has not penetrated into the copper plate. Therefore, it is possible to suppress adverse effects on the drawability and conductivity of the produced wiring, and ensure high wiring performance.

<Nitrogen-containing heterocyclic compound>
The nitrogen-containing heterocyclic compound (also referred to as "nitrogen-containing heterocyclic compound") contained in the treatment liquid of the present invention is a compound having both a nitrogen-containing heterocycle (nitrogen-containing heterocycle) and a functional group containing a nitrogen atom or an oxygen atom. The number of nitrogen atoms in the nitrogen-containing heterocycle is preferably 2 to 4, at least one of which is NH. When the treatment liquid contains such a nitrogen-containing heterocyclic compound, it interacts with copper in the copper plate, improving the adhesion between the copper plate and the resin layer.

The functional group containing a nitrogen atom or an oxygen atom is preferably, for example, any one of -COOH, -NH ₂ , -OH, -NHR, or -NR _2. The functional group is particularly preferably -COOH, -NH ₂ , or -NR _2. Here, R represents an alkyl group. Since the functional group is a water-soluble functional group, the performance after washing with water is improved.

It is particularly preferable that the nitrogen-containing heterocyclic compound has a structure represented by the following general formula 1 or 2. When the nitrogen-containing heterocyclic compound has this structure, it is easily soluble in water and in an alkaline aqueous solution, and the nitrogen atom content ratio on the copper plate surface is easily controlled to within the above-mentioned range.

In the formula, W ₁ to W ₇ represent a carbon atom or a nitrogen atom, 2 to 4 of W ₁ to W ₇ represent nitrogen atoms, and at least one represents NH. W ₁ to W ₇ form a condensed ring.
Y ₁ to Y ₅ each represent a carbon atom or a nitrogen atom, and 2 to 4 of Y ₁ to Y ₅ each represent a nitrogen atom, and at least one of them represents NH. Y ₁ to Y ₇ together form a condensed ring.
Z ₁ represents -COOH, -NH ₂ , -OH, -NHR or -NR _2. Z ₂ represents -COOH, -OH, -NHR or -NR ₂ , where R represents an alkyl group.
L represents a single bond or a linking group.

The linking group is composed of an atom or an atomic group including a carbon atom, a nitrogen atom, a sulfur atom, and an oxygen atom. Specific examples include -O-, -S-, -N(R)-, -CO-, and -SO ₂ -.
, alkylene groups (e.g., methylene, ethylene, propylene, 1,4-cyclohexylene, dodecylene, hexadecylene, 2-ethylhexylene, 2-hexyldecylene, etc.), arylene groups (e.g., phenylene, naphthylene, etc.), or combinations thereof. R represents a hydrogen atom, an alkyl group, or a cycloalkyl group.

The following are exemplary compounds that may be used as the nitrogen-containing heterocyclic compound of the present invention, but the nitrogen-containing heterocyclic compound of the present invention is not limited to these.

The treatment solution of the present invention may contain only one type of nitrogen-containing heterocyclic compound, or two or more types.

<Solvent>
The treatment liquid of the present invention contains the above-mentioned nitrogen-containing heterocyclic compound, and from the viewpoint of solubility, it is preferable that the treatment liquid contains at least water or an alcohol as a solvent.
Examples of the alcohol include methanol, ethanol, and 2-propanol.

The water used in the treatment liquid is preferably ion-exchanged water with few impurities. For example, the magnesium ion concentration in the water is preferably 5 ppm by mass or less, and more preferably 4 ppm by mass or less. Also, the sulfide ion concentration in the water is preferably 5 ppm by mass or less.
In this type of ion-exchanged water, the magnesium ion or sulfide ion concentration can be controlled by passing tap water containing a trace amount of magnesium ions or tap water containing a trace amount of sulfide ions through an ion exchange resin multiple times.
By using ion-exchanged water with fewer impurities, the wiring drawability and wiring conductivity can be improved.

The solvent may be water or alcohols in combination of two or more kinds.
Specifically, the mass ratio of water to alcohol is preferably within the range of 100:0 to 50:50, and more preferably within the range of 100:0 to 75:25.

The nitrogen-containing heterocyclic compound is preferably contained in the entire treatment liquid in a range of 1 to 1000 ppm by mass from the viewpoint of film-forming properties. It is particularly preferable to contain the compound in a range of 1 to 200 ppm by mass.

Furthermore, the treatment liquid of the present invention may contain other components in addition to those described above, but does not contain a polymer, polymerizable monomer or oligomer, i.e., does not contain a resin and consists only of non-polymerizable materials.
Examples of the other components include surfactants, preservatives, stabilizers, acids, bases, and pH adjusters.

[Laminate]
The laminate of the present invention is a laminate in which a surface modification layer and a resin layer are successively provided on a copper plate, and the surface modification layer is made of the treatment liquid described above.

The treatment liquid contains the nitrogen-containing heterocyclic compound, which is a compound having a nitrogen-containing heterocycle and a functional group containing a nitrogen atom or an oxygen atom, and the number of nitrogen atoms in the nitrogen-containing heterocycle is 2 to 4, at least one of which is NH.
The surface modification layer contains the nitrogen-containing heterocyclic compound, which causes interactions between the copper plate and the surface modification layer, and between the surface modification layer and the resin layer, thereby improving the adhesion between the copper plate and the resin layer.
In particular, it is preferable that the nitrogen-containing heterocyclic compound has a structure represented by the general formula 1 or 2 from the viewpoint of improving the adhesion between the copper plate and the resin layer.

In the laminate, it is preferable that the heterocycle of the nitrogen-containing heterocyclic compound is oriented in a direction approximately perpendicular to the copper plate, and the functional group of the nitrogen-containing heterocyclic compound is oriented in a direction approximately perpendicular to the resin layer. This allows the functional group to get closer to the resin layer, resulting in a stronger interaction, which is preferable in terms of improving adhesion.

The orientation of the nitrogen-containing heterocyclic compound is optimized by using, for example, quantum chemical calculation software Gaussian 16 (manufactured by Gaussian Corporation) and B3LYP (density functional theory) in DFT calculation.
The calculation is performed using SDD (Stuttgart/Dresden ECP) as the basis function for copper, and 6-31G(d) is used for the other elements. The initial position is determined as the position where the copper ion becomes stable in the space around the ligand in the Grid scan module of the software Material Science Suite manufactured by Schrodinger.

The optimal structure calculated above will be described with reference to FIG. 2, taking the exemplary compound (10) as an example. The interaction site between the exemplary compound (10) and copper (Cu) is taken as the axial direction. A center line X perpendicular to the axial direction is drawn at the center of the compound. In this case, it is preferable that the interaction site with copper (Cu) and the specific functional group are oriented on opposite sides of the center line X.

Specifically, when the optimized structure calculated above is presented in Winmostar, it is preferable that at least one angle selected from the copper atom (Cu) (reference number 101 in FIG. 2) - the nitrogen atom (N) (reference number 102 in FIG. 2) - the specific functional group (reference number 103 in FIG. 2) is 140° or more.
For example, in the exemplary compound (10), the angle formed by the copper atom--the nitrogen atom in the heterocyclic compound structure--the nitrogen atom at the terminal of the alkylamino group is 170°.
By orienting in this way, the nitrogen atom (N) interacting with copper in the condensed ring of the nitrogen-containing heterocyclic compound and the alkylamino group (N) of the functional group are present at diagonal corners of the molecular skeleton, so that the nitrogen atom (N) is perpendicular to the copper plate and the alkylamino group (N) of the specific functional group can approach the resin layer more closely, resulting in a stronger interaction (see FIG. 1).

The laminate of the present invention can be applied to, for example, printed circuit boards (printed wiring boards) or electronic devices.
The printed circuit board can be formed by a method for forming a metal wiring pattern by photolithography, as described below.
Examples of the electronic device include smartphones, tablet terminals, personal computers, servers, routers, communication base stations, display devices, and home appliances.

The configuration of the laminate of the present invention will be described below.
The laminate of the present invention is a laminate in which a surface modification layer and a resin layer are successively provided on a copper plate. That is, the copper plate and the surface modification layer are adjacent to each other, and the surface modification layer and the resin layer are adjacent to each other.

<Copper plate>
The copper plate is a layer containing copper as a main component. Here, the main component means a component contained in an amount of 50 mass % or more.

The copper plate preferably contains copper or a copper alloy as a main component.
The copper plate can be formed from a metal foil, by plating, or by a vacuum film forming method.

The thickness of the copper plate is not particularly limited, and may be, for example, a thickness that corresponds to the thickness of the metal wiring pattern to be formed.

In forming the metal wiring pattern, a metal-clad laminate in which a copper plate is formed on an insulating layer is used, so the laminate of the present invention preferably has an insulating layer under the copper plate. The insulating layer is not particularly limited, and a resin sheet or prepreg that is generally used as an insulating layer can be used.

The laminate having an insulating layer as described above corresponds to laminate 6 in FIG. 5, which shows the resist layer formation process described below.

<Surface modification layer>
The surface modification layer can be formed by cleaning the surface of the copper plate with an acid such as hydrochloric acid or formic acid, applying the treatment solution of the present invention to the surface of the copper plate, rinsing with water, and drying, as described below.

The thickness of the surface modification layer is not particularly limited, but from the viewpoint of the effects of the present invention, it is preferable that the thickness is within the range of 0.1 to 20 nm.

<Resin Layer>
The resin layer used in the present invention is not particularly limited, but examples thereof include thermoplastic resins such as acrylonitrile/styrene copolymer resin (AS resin), acrylonitrile/butadiene/styrene copolymer resin (ABS resin), fluororesin, polyamide, polyethylene, polyethylene terephthalate, polyvinylidene chloride, polyvinyl chloride, polycarbonate, polystyrene, polysulfone, polypropylene, cyclopolyolefin resin, and liquid crystal polymer, thermosetting resins such as epoxy resin, phenol resin, polyimide, polyurethane, bismaleimide-triazine resin, modified polyphenylene ether, and cyanate ester, and ultraviolet-curable resins such as ultraviolet-curable epoxy resin and ultraviolet-curable acrylic resin. These resins may be modified with a functional group, and may be reinforced with glass fiber, aramid fiber, or other fibers.

When the laminate of the present invention is a printed circuit board laminate, the resin layer may be a commercially available resin film or prepreg (a sheet-like fiber impregnated with a liquid resin). For example, resins containing fluororesins, cyclopolyolefin resins, liquid crystal polymers, epoxy resins, phenolic resins, polyimides, bismaleimide-triazine resins, modified polyphenylene ethers, and cyanate esters are preferably used.
In addition, when the laminate of the present invention forms wiring on a printed circuit board (when it is a metal wiring pattern), a commercially available liquid resist or dry film resist can be used for the resin layer. UV-curable epoxy resins containing alkali-soluble resins, UV-curable acrylic resins, and polyimides are preferably used.

The method for forming a metal wiring pattern according to the present invention is a method for forming a metal wiring pattern by photolithography. In addition, the method preferably includes a step of forming a surface modification layer between the copper plate and the resist using the treatment liquid of the present invention.

<Method of forming metal wiring pattern>
Specifically, the metal wiring pattern is formed by the following steps (A) to (F).
Step (A): A step of acid-cleaning a metal-clad laminate having a copper plate formed on an insulating layer. Step (B): A step of forming a surface-modified layer on the copper plate of the metal-clad laminate using the treatment liquid of the present invention. Step (C): A step of forming a resist layer containing a photosensitive resin on the surface-modified layer. Step (D): A step of patterning the resist layer by exposure and development. Step (E): A step of etching the surface-modified layer and the copper plate through the resist layer. Step (F): A step of peeling off the resist layer from the metal-clad laminate.

Each process will be explained using Figures 3 to 8.

In step (A), a metal-clad laminate 5 (see FIG. 3 ) in which a copper plate 2 is formed on an insulating layer 1 is subjected to acid washing, thereby removing dirt, antioxidants, oxide films, and the like adhering to the surface of the copper plate, which may hinder the interaction between the nitrogen-containing heterocyclic compound and the copper plate.
The acid cleaning is preferably performed by a dipping method or a spraying method. Examples of the acid used for cleaning include hydrochloric acid and formic acid. The hydrochloric acid (HCl) is preferably an aqueous solution of 1 to 10% by mass. In the case of the dipping method, the conditions are preferably a temperature of 25° C. and a dipping time of 1 to 10 minutes.

The insulating layer 1 is an insulating layer that serves as the base material for the metal wiring pattern. The insulating layer 1 is made of an insulating material such as resin, and may be a prepreg in which a base material such as paper or glass is impregnated with resin.

The copper plate 2 is the same as the copper plate in the laminate described above.

In step (B), a surface modification layer 3 is formed on the copper plate 2 of the metal-clad laminate 5 using the treatment liquid of the present invention (see FIG. 4). Specifically, the treatment liquid is applied to the copper plate 2 after acid cleaning to form the surface modification layer 3. There are no particular limitations on the thickness of the surface modification layer 3, but from the viewpoint of the effects of the present invention, it is preferable that the thickness is within the range of 0.1 to 20 nm.

Between step (B) and the next step (C), there is a step of washing the metal-clad laminate 5 on which the surface modification layer 3 has been formed with water. This allows the nitrogen atom content ratio to the copper atoms on the surface of the copper plate after washing to be within the range of 1 to 80%. In addition, the interaction with the copper plate is insufficient, and excess of the treatment liquid can be removed.

Here, the water washing temperature is preferably within a range of 15 to 45° C., and more preferably within a range of 20 to 30° C. Furthermore, the time from application of the treatment liquid to the copper plate until water washing is preferably within 500 hours, and more preferably within 200 hours. Furthermore, the time left after water washing is preferably within 500 hours, and more preferably within 100 hours.
As a method for washing with water, a shower is preferably used. The shower pressure is preferably 0.1 to 0.5 MPa, and the shower time is preferably 10 to 90 seconds.

In step (C), a resist layer 4 containing a photosensitive resin is formed on the surface modification layer 3 (see FIG. 5). The laminate 6 in this state includes the copper plate 2, the surface modification layer 3, and the resist layer 4, and thus corresponds to the laminate of the present invention.

The resist layer 4 is not particularly limited as long as it contains a photosensitive resin that can be patterned by photolithography, similar to the resist layer of the laminate. The resist layer 4 can be formed by laminating a dry film resist or applying a liquid resist material.

In step (D), the resist layer 4 is patterned by exposure and development (see FIG. 6). Specifically, the resist layer 4 is exposed using a photomask that can expose the resist layer 4 in any pattern. Thereafter, unnecessary portions of the resist layer 4 are dissolved and removed using a developer, thereby forming a pattern. It is preferable to wash the resist layer 4 with water after development.

The exposure conditions and development conditions are not particularly limited, and conventionally known conditions can be used. Since the development time also affects the work efficiency in the process, it is preferable to be able to pattern in a shorter time. The development time varies depending on the dry film used, but for example, 3 minutes or less is preferable, and 1 minute or less is more preferable.

In step (E), the surface modification layer 3 and the copper plate 2 are etched through the resist layer 4 (see FIG. 7). Specifically, the surface modification layer 3 and the copper plate 2 are dissolved by wet etching using an etching solution in the areas where the resist layer 4 has been removed. This results in patterning of the surface modification layer 3 and the copper plate 2.

The etching conditions are not particularly limited, and conventionally known conditions can be applied.

In step (F), the resist layer 4 is peeled off from the metal-clad laminate 5 (see FIG. 8). At this time, due to the effect of the present invention, the surface modification layer 3 is easily peeled off from the resist layer 4. Therefore, the surface modification layer 3 is likely to remain on the copper plate 2 of the metal-clad laminate 5, but the surface modification layer 3 may remain on the copper plate 2 or may be peeled off together with the resist layer 4.

The resist layer 4 is stripped using a stripping solution. The stripping solution is not particularly limited, and a conventionally known solution can be used. As the stripping solution, for example, an alkaline aqueous solution having a pH of 7 or more calculated at 25° C. is preferable, and examples thereof include an aqueous sodium hydroxide solution.
By cleaning and stripping using such a stripping solution, the ratio of nitrogen atoms to copper atoms on the surface of the copper plate after cleaning can be made 55% or less.

Here, the cleaning temperature (peeling temperature) with the alkaline aqueous solution is preferably within a range of 25 to 70° C., and more preferably within a range of 35 to 60° C. Furthermore, the time from application of the treatment liquid onto the copper plate to washing the treatment liquid with water until application of the alkaline aqueous solution is preferably within 500 hours, and more preferably within 100 hours. Furthermore, the time left after washing with the alkaline aqueous solution is preferably within 500 hours, and more preferably within 100 hours.
The washing method with the alkaline aqueous solution is not particularly limited, but immersion is preferred. The immersion time is preferably 20 to 120 seconds.

By carrying out the above steps, the metal wiring pattern 7 can be formed.

The method for forming a metal wiring pattern makes it possible to form a high-density, high-definition metal wiring pattern. Therefore, by attaching electronic components to the metal wiring pattern as required, a high-density, high-definition printed circuit board (printed wiring board) can be manufactured.

Method for forming a printed circuit board laminate
The method for forming a laminate (printed circuit board laminate) according to the present invention is a method for forming a resin layer on a copper plate, and includes a step of forming a surface modification layer between the copper plate and the resin layer using the treatment liquid of the present invention.
The copper plate may be solid or patterned, and the lamination method may be a known method such as hot pressing.
The resin layer may be a commercially available resin film or prepreg (a sheet-like fiber impregnated with a liquid resin). The resin layer may preferably be made of a resin containing a fluororesin, a cyclopolyolefin resin, a liquid crystal polymer, an epoxy resin, a phenolic resin, a polyimide, a bismaleimide-triazine resin, a modified polyphenylene ether, or a cyanate ester.
Before lamination, the bonding surface of the resin layer may be subjected to surface treatment such as corona treatment or plasma treatment.

The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these. In the following examples, unless otherwise specified, operations were performed at room temperature (25°C). Furthermore, unless otherwise specified, "%" and "parts" mean "% by mass" and "parts by mass", respectively.

<Preparation of Treatment Solution 1>
Tap water containing a trace amount of magnesium ions was passed through an ion exchange resin multiple times to control the magnesium ion concentration to 0.01 ppm by mass. Tap water containing a trace amount of sulfide ions was passed through an ion exchange resin multiple times to control the sulfide ion concentration to 0.01 ppm by mass.
The above-mentioned exemplary compound (10) (nitrogen-containing aromatic heterocyclic compound) was added to a solvent consisting of 90% by mass of purified ion-exchanged water and 10% by mass of ethanol so as to have a concentration of 100 ppm by mass. Further, hydrochloric acid and sodium hydroxide were added to the solvent so as to have a pH of 7 at 25° C., thereby preparing treatment liquid 1.

<Preparation of Processing Solutions 2 to 82>
Treatment solutions 2 to 82 were prepared in the same manner as in the preparation of treatment solution 1, except that the magnesium ion concentration, sulfide ion concentration, type and amount of compound added (content), and pH of the treatment solution at 25° C. were changed as shown in the table below.

Comparative Compound 1 and Comparative Compound 2 in the table below are as shown below. The other compounds are the compounds exemplified in the explanation of the nitrogen-containing heterocyclic compound according to the present invention.

<Formation of Metal Wiring Pattern (Laminate) 1>
The following steps (A) to (F) were carried out to form a metal wiring pattern 1.

<<Step (A)>>
A copper-clad laminate (R-1766 manufactured by Panasonic Corporation) having a copper plate formed on an insulating layer was washed with hydrochloric acid using a hydrochloric acid washing solution (CP-30 manufactured by Sanwa Chemical Industry Co., Ltd.) and a spray-type washing device. The copper plate after the hydrochloric acid washing was then rinsed with water.

<<Step (B)>>
The treatment solution 1 prepared above was applied to the copper plate of the copper-clad laminate that had been washed with hydrochloric acid and rinsed with water using a spray type applicator, and then the plate was rinsed with water.
The washing was performed using pure water and a shower at a shower pressure of 0.2 MPa for a shower time of 1 minute.
The water temperature during washing was 25° C., and the time for leaving the treatment solution after application until washing was 1 minute.
After washing with water, the surface was drained with a PVA roller and dried with an air knife at 80° C. to form a surface modified layer having a thickness of 5 nm.

<<Step (C)>>
A dry film resist (AK-4034 manufactured by Asahi Kasei Corporation) was laminated on the surface modification layer using a hot roll laminator under conditions of a roll temperature of 105° C., an air pressure of 0.35 MPa, and a lamination speed of 1.5 m/min to form a resist layer.
The dry film resist used (AK-4034 manufactured by Asahi Kasei Corporation) had a support made of a polyethylene terephthalate film on one side and a protective layer made of a polyethylene film on the other side. The lamination was performed by peeling off the protective layer while adhering the surface where the protective layer was located to the copper plate via the surface modification layer.

<<Step (D)>>
The resist layer was exposed to light using a chrome glass mask with a parallel light exposure machine (Oak Corp. HMW-801) at 60 mj/ ^cm2 , which is the recommended condition for dry film resist.
The support was peeled off from the exposed resist layer, and then the unexposed portion of the resist layer was dissolved and removed using a developer consisting of an aqueous solution of 1% by mass of sodium carbonate (Na ₂ CO ₃ ) and an alkali developer at 30° C. for 3 minutes (development time), followed by washing with water and development.
By the above operations, the resist layer was patterned.

<<Step (E)>>
The surface modification layer and the copper plate were etched by a dip method using an etching solution consisting of an aqueous solution of 2 mass % hydrochloric acid (HCl) and 2 mass % ferric chloride (FeCl ₃ ) at a temperature of 30° C. for a dip time of 1 minute.

<<Step (F)>>
In the alkaline aqueous solution cleaning process (resist layer peeling process), a stripping solution made of an aqueous sodium hydroxide (NaOH) solution was used. The aqueous sodium hydroxide solution was adjusted to have a pH of 13 at 25°C. The resist layer was peeled off from the copper-clad laminate under the conditions of a sodium hydroxide aqueous solution temperature of 50°C and an immersion time of 50 seconds. As a result, a metal wiring pattern 1 was obtained.
After rinsing with the treatment solution, the time until peeling (cleaning) with the aqueous sodium hydroxide solution was 20 minutes.

<Formation of Metal Wiring Patterns 2 to 82>
In the formation of the metal wiring pattern 1, the treatment liquid 1 was changed to the treatment liquids shown in the table below. Furthermore, the water temperature during washing with water, the liquid temperature during washing with an alkaline aqueous solution, the time from application of the treatment liquid to washing with water, and the time from washing with water to washing with an alkaline aqueous solution were also changed as shown in the table below, but metal wiring patterns 2 to 82 were formed in the same manner.
In addition, in each case of washing with an alkaline aqueous solution, an aqueous solution of sodium hydroxide (NaOH) was used, and the aqueous solution was adjusted to have a pH of 13 at 25°C.

<Ratio of Nitrogen Atoms to Copper Atoms After Washing with Water (X) and Ratio of Nitrogen Atoms to Copper Atoms After Washing with Alkaline Aqueous Solution (Y)>
In step (B), the ratio (X) of nitrogen atoms to copper atoms on the copper plate surface after coating with the treatment liquid and rinsing with water was measured by the above-mentioned XPS.
In step (F), the ratio (Y) of nitrogen atoms to copper atoms on the copper plate surface after washing with the alkaline aqueous solution was measured by the XPS described above. The results are shown in the table below.

The XPS measurement conditions are as follows.
XPS measurement device: Quantera SXM (manufactured by ULVAC-PHI, Inc.)
X-ray source: monochromatic Al-Kα radiation, 100 μm, 25 W, 15 kV
Signal extraction angle: 45 degrees Analysis area: 500 μm x 500 μm
As a measurement method, first, a wide scan measurement was performed in the binding energy range from -20 eV to 1270 eV with a pass energy of 224 eV to determine what elements were detected.
Next, narrow scan measurements were performed on all the detected elements at a pass energy of 140 eV. Note that the wide scan and narrow scan were performed at different positions on the same sample.
As a quantification method, the surface element composition was quantified using analysis software MultiPak manufactured by ULVAC-PHI, Inc. The background of the spectrum of each element was obtained by the Shirley method for elements other than copper and the linear method for copper, and the surface element composition was obtained from the obtained peak area using the relative sensitivity coefficient method.
Then, from the obtained elemental composition, the content ratio of nitrogen atoms to copper atoms (N atoms (atomic %)/Cu atoms (atomic %)×100)%) was calculated.

Furthermore, when the content ratio of nitrogen atoms to copper atoms after cleaning with an alkaline aqueous solution is (Y) (%) and the content ratio of nitrogen atoms to copper atoms after rinsing with water is (X) (%), the value of "(Y/X) x 100 (%)" is shown in the table below.

[evaluation]
<Wiring drawing ability>
After the above step (D) (development step), 100 randomly selected points were selected from the patterned wiring, and the thickness of the wiring at each point was measured using a VHX-5000 (manufactured by Keyence Corporation). From the measured thickness of each wiring, the variation was calculated by "(maximum line width - minimum line width) / average line width x 100 (%)". The calculated variation in wiring thickness was evaluated according to the following criteria, and the evaluations "AA" and "A" were deemed to be acceptable for practical use.
(standard)
AA: The variation in wiring thickness after development is 5% or less.
A: The variation in wiring thickness after development is greater than 5% and equal to or less than 8%.
B: The variation in wiring thickness after development is greater than 8%.

<Wiring Conductivity>
After the above step (F) (peeling off the resist layer with an aqueous sodium hydroxide solution), 100 random locations were selected from the formed wiring, and the impedance of the wiring at each location was measured using a ZA57630 (manufactured by Endo Scientific Co., Ltd.). From each measured impedance, the variation was calculated by "(maximum value - minimum value) / average impedance x 100 (%)". The calculated variation of the wiring impedance was evaluated according to the following criteria, and the evaluations "AA" and "A" were deemed to be acceptable for practical use.
(standard)
AA: The variation in wiring impedance after etching is 5% or less.
A: The variation in wiring impedance after etching is more than 5% and 8% or less.
B: The variation in wiring impedance after etching is greater than 8%.

As shown by the above results, the treatment solution of the present invention is found to have superior wiring drawing properties and wiring conductivity compared to the treatment solution of the comparative example.

Reference Signs List 1: Insulating layer 2: Copper plate 3: Surface modification layer 4: Resist layer 5: Metal-clad laminate 6: Laminate 7: Metal wiring pattern 10: Copper plate 20: Resin layer 30: Surface modification layer A: Center line

Claims (9)

A treatment solution for forming a surface modification layer to be interposed between a copper plate and a resin layer,
Contains a nitrogen-containing heterocyclic compound,
The content of the nitrogen-containing heterocyclic compound is within the range of 1 to 1000 ppm by mass, and
the content ratio of nitrogen atoms to copper atoms of the copper plate measured by X-ray photoelectron spectroscopy (XPS) after the copper plate is applied and washed with water is within a range of 1 to 80%;
After the water washing and after cleaning with an alkaline aqueous solution having a pH of 7 or more converted at 25°C, the content ratio of nitrogen atoms to copper atoms measured by X-ray photoelectron spectroscopy (XPS) on the surface of the copper plate is 55% or less, and
a content ratio of nitrogen atoms to copper atoms, as measured by X-ray photoelectron spectroscopy (XPS) of the surface of the copper plate after cleaning with the alkaline aqueous solution, is 95% or less of a content ratio of nitrogen atoms to copper atoms, as measured by X-ray photoelectron spectroscopy (XPS) of the surface of the copper plate after rinsing with water. the nitrogen-containing heterocyclic compound is a compound having a nitrogen-containing heterocycle and a functional group containing a nitrogen atom or an oxygen atom,
2. The treatment liquid according to claim 1, wherein the nitrogen-containing heterocycle contains 2 to 4 nitrogen atoms, at least one of which is NH. 3. The treatment liquid according to claim 2, wherein the functional group is any one of --COOH, _--NH.sub.2 , --OH, --NHR, and _--NR.sub.2 , where R represents an alkyl group. The treatment liquid according to claim 1 , wherein the nitrogen-containing heterocyclic compound has a structure represented by the following general formula 1 or 2:

[In the formula, W ₁ to W ₇ represent a carbon atom or a nitrogen atom, two to four of W ₁ to W ₇ represent nitrogen atoms, and at least one represents NH.
Y ₁ to Y ₅ each represent a carbon atom or a nitrogen atom, and two to four of Y ₁ to Y ₅ represent nitrogen atoms, and at least one represents NH.
Z ₁ represents -COOH, -NH ₂ , -OH, -NHR or -NR _2. Z ₂ represents -COOH, -OH, -NHR or -NR ₂ , where R represents an alkyl group.
L represents a single bond or a linking group. The treatment liquid according to claim 1 , which contains at least water or an alcohol. The ratio of nitrogen atoms to copper atoms measured by X-ray photoelectron spectroscopy (XPS) on the surface of the copper plate after the water washing is within the range of 5 to 65%, and
2. The treatment solution according to claim 1, wherein a content ratio of nitrogen atoms to copper atoms of the surface of the copper plate after cleaning with the alkaline aqueous solution is within a range of 0 to 35%, as measured by X-ray photoelectron spectroscopy (XPS). 2. The treatment solution according to claim 1, wherein a content ratio of nitrogen atoms to copper atoms, as measured by X-ray photoelectron spectroscopy (XPS) of the surface of the copper plate after cleaning with the alkaline aqueous solution, is 85% or less of a content ratio of nitrogen atoms to copper atoms, as measured by X-ray photoelectron spectroscopy (XPS) of the surface of the copper plate after rinsing with water. 2. The treatment liquid according to claim 1, wherein the content of the nitrogen-containing heterocyclic compound is within a range of 1 to 200 ppm by mass. A laminate in which a surface modification layer and a resin layer are sequentially provided on a copper plate,
A laminate, wherein the surface modification layer is made of the treatment liquid according to any one of claims 1 to 8.

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