KR20240079145A - Surface modifier and manufacturing method of printed wiring board - Google Patents

Abstract

The object of the present invention is to provide a surface modifier that can further improve the adhesion between a metal layer and a resin layer, and a method of manufacturing a printed wiring board using the surface modifier.
The surface modifier of the present invention is a surface modifier that forms a surface modification layer between a metal layer and a resin layer, and is characterized in that the absorbance change rate Z, obtained by the following formula A, is in the range of 5 to 30%.
Formula AZ[％]=(XY)/X×100
[Let the absorbance of the surface modifier before application be the absorbance X. Let the absorbance of the excess surface modifier not adhere to the copper plate after application to the copper plate be the absorbance Y. Each absorbance adopts the absorbance at the maximum absorption within the 300 to 800 nm wavelength range of the absorption spectrum obtained by spectrophotometric measurement.]

Description

Surface modifier and manufacturing method of printed wiring board {SURFACE MODIFIER AND MANUFACTURING METHOD OF PRINTED WIRING BOARD}

The present invention relates to a surface modifier and a method of manufacturing a printed wiring board.

More specifically, it relates to a surface modifier that can further improve the adhesion between the metal layer and the resin layer, and a method of manufacturing a printed wiring board using the surface modifier.

In recent years, with the advancement of data socialization, printed wiring boards (also referred to as “printed boards”) with high-density and high-precision wiring have been required. In the manufacturing process of a printed wiring board, resin materials such as etching resist, plating resist, soldering resist, and prepreg are bonded to the surface of the metal layer or metal wiring. In the manufacturing process of a printed wiring board and the product after manufacturing, high adhesion is required between the metal layer and the resin layer.

Therefore, conventionally, in order to increase the adhesion between the metal layer and the resin layer, the surface of the metal layer was roughened and adhesion was performed by the anchor effect. However, the surface of the roughened metal layer may cause transmission loss for short-wavelength radio waves used in communication technologies such as 5G and 6G. Therefore, there is a demand for a technique to increase the adhesion between the metal layer and the resin layer without roughening the surface of the metal layer.

As a method of increasing the adhesion between the metal layer and the resin layer without roughening the surface of the metal layer, the following techniques are known. Patent Document 1 discloses a method of forming an adhesion-improving film on the surface of a metal layer to improve adhesion with a resin layer. Patent Document 2 discloses a method of improving adhesion by including a sulfur-containing compound and a nitrogen-containing compound in a photosensitive resin. Patent Document 3 discloses a method of improving the adhesion between the metal and the resin by forming an organic film on the surface of the metal using a treatment liquid containing a nitrogen-containing compound having an amino group.

However, in these techniques, although the adhesion between the metal layer and the resin layer is improved to some extent, sufficient adhesion has not yet been obtained.

Japanese Patent Publication No. 2017-203073 Japanese Patent Publication No. 2020-34933 Japanese Patent Publication No. 2008-274311

The present invention was made in consideration of the above problems and situations, and the problem to be solved is to provide a surface modifier that can further improve the adhesion between the metal layer and the resin layer, and a method of manufacturing a printed wiring board using the surface modifier.

In order to solve the above problem, the present inventor studied the causes of the above problem and found that a surface modifier whose absorbance change rate before and after application to the metal layer is within a specific range has a high performance in improving the adhesion between the metal layer and the resin layer. After finding out, we arrived at the present invention.

That is, the above-described problem regarding the present invention is solved by the following means.

1. It is a surface modifier that forms a surface modification layer between the metal layer and the resin layer.

The absorbance change rate Z calculated by the following formula A is within the range of 5 to 30%.

A surface modifier characterized in that.

Formula A Z[%]=(X-Y)/X×100

[Let the absorbance of the surface modifier before application be the absorbance X. Let the absorbance of the excess surface modifier not adhere to the copper plate after application to the copper plate be the absorbance Y. Each absorbance adopts the absorbance at the maximum absorption within the 300 to 800 nm wavelength range of the absorption spectrum obtained by spectrophotometric measurement.]

2. The absorbance change rate Z is in the range of 10 to 30%

A surface modifier characterized in that.

3. The absorbance change rate Z is in the range of 15 to 25%

A surface modifier characterized in that.

4. Contains an adsorbent compound,

The adsorbent compound is a nitrogen-containing compound.

A surface modifier characterized in that.

5. Contains an adsorbent compound and a solvent compound,

The adsorbent compound is a nitrogen-containing compound,

The solvent compound is water or alcohol.

A surface modifier characterized in that.

6. Contains adsorbent compounds and solvent compounds,

The adsorbent compound is a nitrogen-containing heterocyclic compound,

The solvent compound is water or alcohol.

A surface modifier characterized in that.

7. Contains adsorbent compounds and solvent compounds,

The adsorbent compound is a nitrogen-containing heterocyclic compound having at least one of a 6-5 fused ring, a 5-5 fused ring, and a 5-membered ring,

The solvent compound is water or alcohol.

A surface modifier characterized in that.

8. Contains adsorbent compounds and solvent compounds,

The adsorbent compound is a nitrogen-containing heterocyclic compound having a structure represented by the following general formula W, general formula X, or general formula Y,

The solvent compound is water or alcohol.

A surface modifier characterized in that.

[In General Formula W, Rn ₁ and Rn ₂ each independently represent an alkyl group. L represents a linking group. W ₁ to W ₇ each independently represent a carbon atom or a nitrogen atom, at least two of which are nitrogen atoms, one of which is NH, and W ₁ to W ₇ form a condensed ring. m represents an integer greater than 1.]

[In General Formula X, X ₁ to X ₅ each independently represent a nitrogen atom or CR ₁ . R ₁ each independently represents a hydrogen atom, an aryl group, a heteroaryl group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an amino group, a cyano group, a thiol group, a carbonyl group, a halogeno group, a trifluoromethyl group, or a hydroxy group, It may also have a substituent.]

[In General Formula Y, Rn ₁ and Rn ₂ each independently represent an alkyl group. L represents a linking group. Y ₁ to Y ₅ each independently represent a carbon atom or a nitrogen atom, at least two of which are nitrogen atoms, one of which is NH, and Y ₁ to Y ₅ form a heterocycle. m represents an integer greater than 1.]

9. A method of manufacturing a printed wiring board,

Having a process of applying the surface modifier according to any one of claims 1 to 8 on a metal layer to form a surface modification layer with a thickness of 15 nm or less.

A method of manufacturing a printed wiring board, characterized in that.

10. The surface modification layer has a thickness of 5 nm or less.

The manufacturing method of the printed wiring board according to claim 9, characterized in that.

11. The metal layer is a layer containing copper or a copper alloy as its main component.

The manufacturing method of the printed wiring board according to claim 9, characterized in that.

By the means of the present invention, it is possible to provide a surface modifier capable of further improving the adhesion between the metal layer and the resin layer, and a method for manufacturing a printed wiring board using the surface modifier.

The mechanism of expression or action of the effect of the present invention is not clear, but is estimated as follows.

In a surface modification layer composed of many adsorbent compounds laminated, cohesive failure occurs within the layer, so the adhesion between the metal layer and the resin layer cannot be sufficiently improved. Therefore, ideally the surface modification layer is a monomolecular layer of an adsorbent compound. If the adsorption power of the adsorbent compound to the metal layer is too strong, it becomes too laminated on the metal layer, making it impossible to form a monomolecular layer or a layer close to it. On the other hand, even if the adsorption power of the adsorbent compound to the metal layer is too weak, the amount of adsorption becomes too small, making it impossible to sufficiently form a surface modification layer. Therefore, the adsorption power of the adsorbent compound contained in the surface modifier is preferably appropriate because it forms a monomolecular layer or a layer close to this.

Here, the surface modifier of the present invention is characterized in that the absorbance change rate Z, obtained by the following formula A, is in the range of 5 to 30%.

Formula A Z[%]=(X-Y)/X×100

[Let the absorbance of the surface modifier before application be the absorbance X. Let the absorbance of the excess surface modifier not adhere to the copper plate after application to the copper plate be the absorbance Y. Each absorbance adopts the absorbance at the maximum absorption within the 300 to 800 nm wavelength range of the absorption spectrum obtained by spectrophotometric measurement.]

This absorbance change rate Z is a parameter that serves as an index of the adsorption power of the adsorbent compound in the surface modifier. When a surface modifier is applied to a copper plate, a portion of the adsorbent compound contained in the surface modifier adheres to the copper plate. Depending on the amount of the adsorbent compound attached, the content of the adsorbent compound in the surface modifier after application decreases, and the absorbance of the surface modifier accordingly decreases. The stronger the adsorption power of the adsorbent compound, the greater the amount of adsorption due to application, and the greater the decrease in absorbance, so the absorbance change rate Z of the surface modifier increases. The absorbance change rate Z of the surface modifier changes not only depending on the type of adsorbent compound, but also depending on the content of the adsorbent compound or other components. The present inventor has found that the adsorption power of the adsorbent compound is appropriate as long as it is a surface modifier that exhibits an absorbance change rate Z within the range of 5 to 30%. The surface modifier of the present invention can improve the adhesion between the metal layer and the resin layer to a high level because the adsorption power of the adsorbent compound is adequate by satisfying this condition.

1 is a diagram showing the formation process of a metal wiring pattern (metal clad laminate)
2 is a diagram showing the formation process of a metal wiring pattern (formation of a surface modification layer)
3 is a diagram showing the formation process of a metal wiring pattern (formation of a resist layer)
4 is a diagram showing the formation process of a metal wiring pattern (patterning of a resist layer).
5 is a diagram showing the formation process of a metal wiring pattern (etching of the surface modification layer and metal layer)
6 is a diagram showing the formation process of a metal wiring pattern (resist layer peeling).

The surface modifier of the present invention is a surface modifier that forms a surface modification layer between a metal layer and a resin layer, and is characterized in that the absorbance change rate Z obtained by the above formula A is in the range of 5 to 30%.

This feature is a technical feature common to or corresponding to the following embodiments.

As an embodiment of the surface modifier of the present invention, the absorbance change rate Z is preferably within the range of 10 to 30%, and more preferably within the range of 15 to 25%. As a result, the amount of adsorption of the component contained in the surface modifier to the surface of the metal layer becomes more appropriate, making it easier to form a monomolecular layer. Therefore, the adhesion between the metal layer and the resin layer can be further improved.

An embodiment of the surface modifier of the present invention preferably contains an adsorbent compound, and the adsorbent compound is a nitrogen-containing compound.

Nitrogen-containing compounds have a high adhesion improvement because nitrogen atoms tend to interact strongly with the metal layer.

An embodiment of the surface modifier of the present invention preferably contains an adsorbent compound and a solvent compound, the adsorbent compound is a nitrogen-containing compound, and the solvent compound is water or alcohol. Water or alcohol easily dissolve nitrogen-containing compounds.

An embodiment of the surface modifier of the present invention preferably contains an adsorbent compound and a solvent compound, the adsorbent compound is a nitrogen-containing heterocyclic compound, and the solvent compound is water or alcohol. Nitrogen-containing heterocyclic compounds have a higher adhesion improvement because not only nitrogen atoms tend to interact strongly with the metal layer, but also heterocyclic structural portions tend to strongly interact with the resin layer.

As an embodiment of the surface modifier of the present invention, it contains an adsorbent compound and a solvent compound, and the adsorbent compound is a nitrogen-containing heterocyclic compound having at least one of a 6-5 fused ring, a 5-5 fused ring, and a 5-membered ring, It is preferable that the solvent compound is water or alcohol. These nitrogen-containing heterocyclic compounds have higher adhesion improvement.

In an embodiment of the surface modifier of the present invention, it contains an adsorbent compound and a solvent compound, and the adsorbent compound is a nitrogen-containing heterocyclic compound having a structure represented by the following general formula W, general formula X, or general formula Y, It is preferable that the solvent compound is water or alcohol. As a result, these nitrogen-containing heterocyclic compounds have higher adhesion improvement properties.

A method for manufacturing a printed wiring board of the present invention is characterized by comprising the step of applying the surface modifier of the present invention on a metal layer to form a surface modification layer with a thickness of 15 nm or less.

As an embodiment of the method for manufacturing a printed wiring board of the present invention, it is preferable that the thickness of the surface modification layer is 5 nm or less. Thereby, the adhesion between the metal layer and the resin layer can be further improved.

As an embodiment of the method for manufacturing a printed wiring board of the present invention, it is preferable that the metal layer is a layer containing copper or a copper alloy as a main component from the viewpoint of processability and conductivity.

Hereinafter, a detailed description will be given of the present invention, its components, and forms and aspects for carrying out the present invention. In addition, in this application, “to” is used to include the numerical values described before and after as the lower limit and the upper limit.

[Overview of surface modifiers]

The surface modifier of the present invention is a surface modifier that forms a surface modification layer between a metal layer and a resin layer, and the surface modifier is characterized in that the absorbance change rate Z calculated by the following formula A is in the range of 5 to 30%.

Formula A Z[%]=(X-Y)/X×100

[Let the absorbance of the surface modifier before application be the absorbance X. Let the absorbance of the excess surface modifier not adhere to the copper plate after application to the copper plate be the absorbance Y. Each absorbance adopts the absorbance at the maximum absorption within the 300 to 800 nm wavelength range of the absorption spectrum obtained by spectrophotometric measurement.]

Specifically, the absorbance The absorbance X can be specifically obtained by the following method. First, the content of the adsorbent compound in the surface modifier is measured. If the content is less than 20 ppm by mass, the solvent is evaporated and concentrated, and the content is adjusted to 20 ppm by mass. When the content exceeds 20 ppm by mass, the surface modifier is diluted with ion-exchanged water to adjust the content to 20 ppm by mass, regardless of the type of solvent it contains. The absorption spectrum is obtained by spectrophotometry using a surface modifier with the content of the adsorbent compound adjusted to 20 mass ppm. The absorbance at the maximum absorption within the wavelength range of 300 to 800 nm in the absorption spectrum is taken as absorbance

The absorbance Y can be specifically obtained by the following method. First, 100 mL of the surface modifier whose content of the adsorbent compound was adjusted to 20 mass ppm by the above method is applied to a 10 cm x 10 cm copper plate for 1 minute while circulating with a spray device. This spray device uses a structure in which the excess surface modifier that does not adhere to the copper plate circulates through a tank and is applied repeatedly. The spray pressure for application is 0.2 MPa, and the application temperature is 25°C. After application for 1 minute, the surface modifier remaining in the tank of the spray device is taken out. An absorption spectrum is obtained from the extracted surface modifier by spectrophotometry. The absorbance at the maximum absorption within the wavelength range of 300 to 800 nm in the absorption spectrum is taken as absorbance Y.

The surface modifier of the present invention preferably has an absorbance change rate Z in the range of 10 to 30%, and more preferably in the range of 15 to 25%. As a result, the amount of adsorption of the component contained in the surface modifier to the surface of the metal layer becomes more appropriate, making it easier to form a monomolecular layer. Therefore, the adhesion between the metal layer and the resin layer can be further improved.

[Ingredients of surface modifier]

The surface modifier of the present invention preferably contains at least an adsorbent compound and a solvent compound.

The adsorbent compound is a compound that can improve the adhesion between the metal layer and the resin layer by forming a surface modification layer. The adsorbent compound is preferably adsorbed on the surface of the metal layer to form a surface modification layer. Adsorption to the surface of the metal layer is preferably chemical adsorption.

The adsorbent compound is preferably non-photosensitive. “Non-photosensitive” refers to the property of absorbing light and not cleaving intramolecular bonds or polymerizing molecules under normal conditions in the process of forming the surface modification layer.

The adsorbent compound is preferably a nitrogen-containing compound. Nitrogen-containing compounds have a high adhesion improvement because nitrogen atoms tend to interact strongly with the metal layer.

The adsorbent compound is more preferably a nitrogen-containing heterocyclic compound. Nitrogen-containing heterocyclic compounds have a higher adhesion improvement because not only nitrogen atoms tend to interact strongly with the metal layer, but also heterocyclic structural portions tend to strongly interact with the resin layer.

From the viewpoint of adhesion improvement, the adsorbent compound is more preferably a nitrogen-containing heterocyclic compound having at least one of a 6-5 fused ring, a 5-5 fused ring, and a 5-membered ring.

From the viewpoint of improving adhesion, the adsorbent compound is more preferably a nitrogen-containing heterocyclic compound having a structure represented by the following general formula W, general formula X, or general formula Y. Among these, nitrogen-containing heterocyclic compounds having a structure represented by the following general formula W or Y are more preferable.

[In General Formula W, Rn ₁ and Rn ₂ each independently represent an alkyl group. L represents a linking group. W ₁ to W ₇ each independently represent a carbon atom or a nitrogen atom, at least two of which are nitrogen atoms, one of which is NH, and W ₁ to W ₇ form a condensed ring. m represents an integer greater than 1.]

It is more preferable that m represents an integer of 1 to 4.

The nitrogen-containing heterocyclic compound having a structure represented by the general formula W more preferably has a structure represented by the following general formula 1 from the viewpoint of improved adhesion.

[In General Formula 1, Rn ₁ and Rn ₂ each independently represent an alkyl group. L represents a linking group. R ₁ represents a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group, and may also have a substituent. R ₂ represents an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a carboxyl group, an ester group, an amide group, a heteroaryl group, or a halogeno group. n each represents an integer from 0 to 4. m represents an integer of 1 or more. When having a plurality of substituents R ₂ , each substituent R ₂ may be the same or different from each other. In addition, when having a plurality of n, each n may be the same or different from each other, and when having a plurality of m, each m may be the same or different from each other.]

Examples of the substituent that R ₁ may have include an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a carboxyl group, an ester group, an amide group, a heteroaryl group, or a halogeno group (halogen atom).

R ₂ more preferably represents an alkyl group, an aryl group, an alkoxy group, or an aryloxy group.

It is more preferable that m represents an integer of 1 to 4.

The nitrogen-containing heterocyclic compound having a structure represented by General Formula 1 more preferably has a structure represented by the following General Formula 5 from the viewpoint of improved adhesion.

[In General Formula 5, Rn ₁ and Rn ₂ each independently represent an alkyl group. L represents a linking group. R ₂ represents an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a carboxyl group, an ester group, an amide group, a heteroaryl group, or a halogeno group (halogen atom). n each represents an integer from 0 to 4. m represents an integer of 1 or more. When having multiple substituents R ₂ , each substituent R ₂ may be the same or different from each other.]

Rn ₁ and Rn ₂ more preferably represent an alkyl group having 1 to 6 carbon atoms.

R ₂ more preferably represents an alkyl group, an aryl group, an alkoxy group, or an aryloxy group.

It is more preferable that m represents an integer of 1 to 4.

[In General Formula X, X ₁ to X ₅ each independently represent a nitrogen atom or CR ₁ . R ₁ each independently represents a hydrogen atom, an aryl group, a heteroaryl group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an amino group, a cyano group, a thiol group, a carbonyl group, a halogeno group, a trifluoromethyl group, or a hydroxy group, It may also have a substituent.]

CR ₁ preferably has an aryl group or heteroaryl group. It is more preferable that the aryl group or heteroaryl group is substituted with an alkyl group, an alkoxy group, or a carbonyl group.

It is more preferable that X ₁ , X ₂ and X ₄ CR ₁ are represented, and X ₃ and X ₅ represent a nitrogen atom.

[In General Formula Y, Rn ₁ and Rn ₂ each independently represent an alkyl group. L represents a linking group. Y ₁ to Y ₅ each independently represent a carbon atom or a nitrogen atom, at least two of which are nitrogen atoms, one of which is NH, and Y ₁ to Y ₅ form a heterocycle. m represents an integer greater than 1.]

It is more preferable that m represents an integer of 1 to 4.

The nitrogen-containing heterocyclic compound having a structure represented by general formula Y more preferably has a structure represented by the following general formulas 2 to 4 from the viewpoint of improved adhesion.

[In General Formulas 2 to 4, Rn ₁ and Rn ₂ each independently represent an alkyl group. L represents a linking group. R ₁ represents a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group, and may also have a substituent. R ₂ represents an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a carboxyl group, an ester group, an amide group, a heteroaryl group, or a halogeno group. n each represents an integer from 0 to 4. m represents an integer of 1 or more. When having a plurality of substituents R ₂ , each substituent R ₂ may be the same or different from each other. In addition, when having a plurality of n, each n may be the same or different from each other, and when having a plurality of m, each m may be the same or different from each other.]

Examples of the substituent that R ₁ may have include an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a carboxyl group, an ester group, an amide group, a heteroaryl group, or a halogeno group (halogen atom).

R ₂ more preferably represents an alkyl group, an aryl group, an alkoxy group, or an aryloxy group.

It is more preferable that m represents an integer of 1 to 4.

Examples of nitrogen-containing compounds are listed below. The nitrogen-containing compounds according to the present invention are not limited to these.

The adsorbent compound contained in the surface modifier of the present invention may be one type or two or more types.

From the viewpoint of solubility, the surface modifier of the present invention preferably contains at least water or alcohol as a solvent compound. Water is not particularly limited, but from the viewpoint of reducing the content of impurities, ion-exchanged water, distilled water, pure water, etc. are preferable. Examples of alcohols include methanol, ethanol, and 2-propanol. As a solvent compound, two or more types of water or alcohol may be used in combination.

The mass ratio of water and alcohol is preferably within the range of 100:0 to 50:50, and more preferably within the range of 100:0 to 75:25. This makes it easier to form a monomolecular layer of the adsorbent compound.

The concentration of the adsorbent compound is preferably in the range of 0.001 to 0.01 mass%, more preferably in the range of 0.001 to 0.004 mass%, and even more preferably in the range of 0.001 to 0.002 mass%, relative to the total surface modifier. This makes it easier to form a monomolecular layer of the adsorbent compound.

The surface modifier may contain components other than those mentioned above. Other ingredients include surfactants, preservatives, stabilizers, acids, bases, pH adjusters, etc.

The magnesium ion concentration of the surface modifier is preferably 5 mass ppm or less. Additionally, the sulfide ion concentration of the surface modifier is preferably 5 mass ppm or less. These can prevent the adsorbent compound from reacting with magnesium ions or sulfide ions, making it difficult for the adsorbent compound to react with the metal layer.

[Manufacturing method of printed wiring board]

The surface modifier of the present invention can be used in the production of printed wiring boards. Specifically, it can be used when attaching an etching resist (resin layer) for forming a metal wiring pattern to a metal plate (metal layer) before pattern formation in the manufacture of a printed wiring board. Additionally, in the manufacture of printed wiring boards, it can be used when adhering a resin sheet (resin layer) such as a resin film or prepreg to a metal plate (metal layer) that may or may not be patterned.

One embodiment of the method for manufacturing a printed wiring board of the present invention includes a step of applying the surface modifier of the present invention on a metal layer to form a surface modification layer. One embodiment of the method for manufacturing a printed wiring board of the present invention further includes a step of forming a resin layer on the formed surface modification layer.

Metals used in the metal layer include, for example, gold, silver, platinum, zinc, palladium, rhodium, osmium, ruthenium, iridium, copper, nickel, cobalt, iron, tin, chromium, titanium, tantalum, tungsten, indium, aluminum, Metals such as lead and molybdenum, or alloys thereof can be used. Among these, from the viewpoint of processability and conductivity, those containing copper or a copper alloy as the main component are preferable. “Main component” refers to a component contained in an amount of 50% by mass or more.

The metal layer can be formed using metal foil, plating, or a vacuum film forming method.

The thickness of the metal layer is not particularly limited, and may be set according to the thickness of the metal wiring pattern to be formed, for example.

In the method for manufacturing a printed wiring board of the present invention, the metal layer to which the surface modifier is applied may be the metal layer of a metal-clad laminate in which a metal layer is formed on an insulating layer. In this case, the insulating layer of the metal-clad laminate is, for example, a resin sheet or prepreg.

The surface modification layer can be formed by applying the surface modifier of the present invention on a metal layer and drying it.

The thickness of the surface modification layer is not particularly limited, but from the viewpoint of improved adhesion, it is preferably 15 nm or less, more preferably 10 nm or less, and even more preferably 5 nm or less.

The resin contained in the resin layer is not particularly limited, but includes acrylonitrile/styrene copolymer resin (AS resin), acrylonitrile/butadiene/styrene copolymer resin (ABS resin), fluororesin, polyamide, polyethylene, polyethylene terephthalate, Thermoplastic resins such as polyvinylidene chloride, polyvinyl chloride, polycarbonate, polystyrene, polysulfone, polypropylene, cyclopolyolefin resin, liquid crystal polymer, epoxy resin, phenol resin, polyimide, polyurethane, bismaleimide, etc. Thermosetting resins such as triazine resin, modified polyphenylene ether, and cyanate ester, or ultraviolet curable resins such as ultraviolet curable epoxy resin and ultraviolet curable acrylic resin. These resins may be modified with functional groups or may be reinforced with glass fibers, aramid fibers, other fibers, etc.

When the resin layer is an etching resist, for example, an ultraviolet-curable epoxy resin containing an alkali-soluble resin, an ultraviolet-curable acrylic resin, or polyimide are preferably used. The etching resist is not particularly limited as long as it contains a photosensitive resin capable of patterning by photolithography. The etching resist may be a dry film resist or a liquid resist. Additionally, the etching resist may be of a negative type in which the portion exposed to light becomes a pattern, or may be of a positive type in which the portion not exposed to light becomes a pattern.

When the resin layer is a resin film or prepreg, for example, fluororesin, cyclopolyolefin resin, liquid crystal polymer, epoxy resin, phenol resin, polyimide, bismaleimide/triazine resin, modified polyphenylene ether, cyanate ester. A resin containing is preferably used.

Below, an example of a method for forming a metal wiring pattern using the surface modifier of the present invention is shown.

In the manufacture of a printed wiring board, a metal wiring pattern can be formed, for example, by carrying out the following processes (A) to (F).

Process (A): Process of acid washing a metal clad laminate in which a metal layer is formed on an insulating layer.

Process (B): Process of forming a surface modification layer using the surface modifier of the present invention on the metal layer of the metal clad laminate.

Step (C): Step of forming a resist layer containing a photosensitive resin on the surface modification layer.

Process (D): Process of patterning the resist layer by exposure and development

Process (E): A process of etching the surface modification layer and the metal layer through the resist layer.

Process (F): Process of peeling the resist layer from the metal clad laminate.

Each process will be explained using Figures 1 to 6.

In step (A), the metal clad laminate 5 (see Fig. 1) in which the metal layer 2 is formed on the insulating layer 1 is acid washed. As a result, it is possible to remove contamination, antioxidants, oxide films, etc. attached to the metal surface, which inhibit the interaction between the surface modifier and the metal layer. The pickling solution is not particularly limited, and conventionally known ones can be used. Additionally, you may wash with water after acid washing.

The insulating layer 1 is an insulating layer that serves as a base material for a printed wiring board. The insulating layer 1 may contain an insulating material such as resin, and may be a prepreg obtained by impregnating a base material such as paper or glass with the resin.

In step (B), the surface modification layer 3 is formed on the metal layer 2 of the metal clad laminate 5 using the surface modifier of the present invention (see Fig. 2). Specifically, a surface modifier is applied on the metal layer 2 to form the surface modification layer 3.

Between the step (B) and the next step (C), it is preferable to have a step of washing the metal-clad laminate 5 on which the surface modification layer 3 is formed. Thereby, excess surface modifier resulting from insufficient interaction with the metal layer can be removed.

In step (C), a resist layer 4 containing a photosensitive resin is formed on the surface modification layer 3 (see Fig. 3). The laminate 6 in this state includes a metal layer 2, a surface modification layer 3, and a resist layer 4.

For the resist layer 4, the etching resist described above can be used. The resist layer 4 can be formed by bonding dry film resist or applying a liquid resist material.

In step (D), the resist layer 4 is patterned by exposure and development (see Fig. 4). Specifically, the resist layer 4 is exposed using a photomask capable of exposing the resist layer 4 in an arbitrary pattern, and then the unnecessary portion of the resist layer 4 is dissolved using a developer. Patterning by removing. It is desirable to wash with water after development.

Exposure conditions and development conditions are not particularly limited, and conventionally known ones can be applied.

In step (E), the surface modification layer 3 and the metal layer 2 are etched through the resist layer 4 (see Fig. 5). Specifically, the surface modification layer 3 and the metal layer 2 are patterned by dissolving the surface modification layer 3 and the metal layer 2 in the portion where the resist layer 4 was removed by wet etching using an etching liquid. do.

Etching conditions are not particularly limited, and conventionally known ones can be applied.

In step (F), the resist layer 4 is peeled from the metal-clad laminate 5 (see Fig. 6). At this time, the surface modification layer 3 may remain on the metal layer 2 or may be peeled off together with the resist layer 4.

The method of peeling the resist layer 4 is not particularly limited, but it is preferable to peel using a stripping liquid. The stripping solution is not particularly limited, and conventionally known ones can be applied.

Through the above steps, the metal wiring pattern 7 can be formed.

In this method of forming a metal wiring pattern, the adhesion between the metal layer and the resist layer in step (E) is high by using the surface modifier of the present invention with high adhesion improvement. As a result, it is possible to prevent the etching liquid from seeping between the metal layer and the resist layer, and it becomes possible to form a high-density and high-precision metal wiring pattern. Therefore, it becomes possible to manufacture a high-density and high-precision printed circuit board by installing necessary electronic components on a printed wiring board having the metal wiring pattern.

[Example]

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these. Additionally, in the following examples, unless otherwise specified, operations were performed at room temperature (25°C). In addition, unless otherwise specified, “%” and “part” mean “% by mass” and “part by mass”, respectively.

<Preparation of surface modifier>

A solvent was prepared by mixing ion-exchanged water and ethanol in the mass ratio shown in Table 1. To this solvent, the adsorbent compound shown in Table 1 was added so that the content was 0.002% by mass (20 ppm by mass). In this way, each surface modifier (inventions 1 to 16, comparative examples 1 to 6) was prepared. The structure of the adsorbent compound is as shown below.

The magnesium ion concentration, pH, and sulfide ion concentration of each surface modifier were measured according to the industrial water test method of JIS K 0101. The measurement results are as shown in Table 1.

<Formation of metal wiring pattern (no water washing treatment after application of surface modifier)>

The following steps (A) to (F) were performed to form a metal wiring pattern.

[Process (A)]

A 10 cm x 10 cm copper clad laminate (R-1766 manufactured by Panasonic Corporation) with a metal layer formed on the insulating layer was acid washed. For acid washing, an acid washing liquid (CP-30 manufactured by Sanwa Chemical Industry Co., Ltd.) and a spray-type washing device were used. Next, the copper clad laminate was washed with water.

[Process (B)]

100 mL of a surface modifier was applied to the metal layer of the acid-washed and water-washed copper clad laminate for 1 minute while circulating with a spray device. This spray device is structured so that the excess surface modifier that does not adhere to the copper clad laminate circulates through a tank and is repeatedly applied. The spray pressure for application was 0.2 MPa, and the application temperature was 25°C. After application of the surface modifier, without water washing, the metal layer was dried with a PVA roller and dried with an air knife at 80°C to form a surface modification layer.

Additionally, in order to determine the absorbance change rate Z, the absorbance X and absorbance Y of the surface modifier were measured before and after process (B). First, before application, the absorbance X of the surface modifier was measured. Additionally, after application, the surface modifier remaining in the tank of the spray device was taken out and the absorbance Y of the surface modifier was measured. For each absorbance, the absorbance at the maximum absorption within the 300 to 800 nm wavelength range of the absorption spectrum obtained by spectrophotometric measurement was adopted. For the spectrophotometric measurement, a spectrophotometer U-3900H (manufactured by Hitachi High-Tech) was used. The absorbance change rate Z calculated from the measured absorbance

Formula A Z[%]=(X-Y)/X×100

[Process (C)]

On the formed surface modification layer, a dry film resist (AK-4034 manufactured by Asahi Kasei) was laminated using a hot roll laminator to form a resist layer. The laminate conditions were a roll temperature of 105°C, an air pressure of 0.35 MPa, and a laminate speed of 1.5 m/min. The dry film resist used has a support containing a polyethylene terephthalate film on one side, and a protective layer containing a polyethylene film on the other side. Laminating was performed by peeling off the protective layer and bonding the surface where the protective layer was to the metal layer through a surface modification layer.

[Process (D)]

Using a chrome glass mask, the resist layer was exposed to light using a parallel light exposure machine (HMW-801 manufactured by Oak Co., Ltd.). For the exposure conditions, 60 mj/cm ² , which is the recommended condition for dry film resist, was adopted. The mask pattern was used to form 100 lines with a line/space of 50 ㎛/50 ㎛. The support was peeled from the resist layer after exposure. Thereafter, the unexposed portion of the resist layer was dissolved and removed under conditions of 30°C using a developer containing a 1% by mass aqueous solution of sodium carbonate (Na ₂ CO ₃ ) and an alkaline developer. Next, the resist layer was washed with water and developed. Through the above operation, the resist layer was patterned.

[Process (E)]

By the dip method, the surface modification layer and the metal layer were etched under the conditions of a temperature of 30°C and a dip time of 1 minute. An aqueous solution containing 2% by mass of hydrochloric acid (HCl) and 2% by mass of ferric chloride (FeCl ₃ ) was used as the etching solution.

[Process (F)]

The resist layer was peeled from the copper clad laminate under conditions of a temperature of 50°C using a stripping solution containing a 3% by mass aqueous solution of sodium hydroxide (NaOH).

<Formation of metal wiring pattern (with water washing treatment after application of surface modifier)>

A metal wiring pattern was formed by selecting and using some of the prepared surface modifiers in the same manner as the above steps (A) to (F) except that step (B) was changed as follows.

In step (B), the application of the surface modifier was carried out in the same manner as above. After application of the surface modifier, water was applied using a spray device for 50 seconds as a water washing treatment. The application spray pressure of water was 0.2 MPa, and the application temperature was 25°C.

Next, the metal layer was dried with a PVA roller and dried with an air knife at 80°C to form a surface modification layer. The thickness of this surface modification layer was as shown in Table 2.

<Resist adhesion>

The formed metal wiring pattern was observed under a microscope, and resist adhesion was evaluated based on the following criteria. The higher the resist adhesion, the more it is possible to prevent the etchant from seeping between the metal layer and the resist layer, and the higher the survival rate of the metal wiring. The evaluation results were as shown in Table 2.

AA: The residual rate of metal wiring is 99% or more.

A: The survival rate of the metal wiring is 97% or more and less than 99%.

B: The residual ratio of the metal wiring is 95% or more and less than 97%.

C: The residual rate of metal wiring is less than 95%.

<Close fluctuation>

Ten metal wiring patterns were similarly formed, and the resist adhesion of each was evaluated. Based on the evaluation results of the adhesion of 10 resists, the adhesion variation was evaluated according to the following criteria. The evaluation results were as shown in Table 2.

A: In all 10, the evaluation results are the same.

B: 1 out of 10, the evaluation results are different.

C: More than 2 out of 10, the evaluation results are different.

From the above results, it can be confirmed that the surface modifier of the present invention can further improve the adhesion between the metal layer and the resin layer compared to the surface modifier of the comparative example.

1: Insulating layer
2: Metal layer
3: Surface modification layer
4: Resist layer
5: Metal clad laminate
6: Laminate
7: Metal wiring pattern

Claims (11)

It is a surface modifier that forms a surface modification layer between the metal layer and the resin layer.
The absorbance change rate Z calculated by the following formula A is within the range of 5 to 30%.
A surface modifier characterized in that.
Formula AZ[%]=(XY)/X×100
[Let the absorbance of the surface modifier before application be the absorbance X. Let the absorbance of the excess surface modifier not adhere to the copper plate after application to the copper plate be the absorbance Y. Each absorbance adopts the absorbance at the maximum absorption within the 300 to 800 nm wavelength range of the absorption spectrum obtained by spectrophotometric measurement.] The method of claim 1, wherein the absorbance change rate Z is in the range of 10 to 30%.
A surface modifier characterized in that. The method of claim 1, wherein the absorbance change rate Z is in the range of 15 to 25%.
A surface modifier characterized in that. 2. The method of claim 1, comprising an adsorbent compound,
The adsorbent compound is a nitrogen-containing compound.
A surface modifier characterized in that. The method of claim 1, comprising an adsorbent compound and a solvent compound,
The adsorbent compound is a nitrogen-containing compound,
The solvent compound is water or alcohol.
A surface modifier characterized in that. The method of claim 1, comprising an adsorbent compound and a solvent compound,
The adsorbent compound is a nitrogen-containing heterocyclic compound,
The solvent compound is water or alcohol.
A surface modifier characterized in that. The method of claim 1, comprising an adsorbent compound and a solvent compound,
The adsorbent compound is a nitrogen-containing heterocyclic compound having at least one of a 6-5 fused ring, a 5-5 fused ring, and a 5-membered ring,
The solvent compound is water or alcohol.
A surface modifier characterized in that. The method of claim 1, comprising an adsorbent compound and a solvent compound,
The adsorbent compound is a nitrogen-containing heterocyclic compound having a structure represented by the following general formula W, general formula X, or general formula Y,
The solvent compound is water or alcohol.
A surface modifier characterized in that.

[In General Formula W, Rn ₁ and Rn ₂ each independently represent an alkyl group. L represents a linking group. W ₁ to W ₇ each independently represent a carbon atom or a nitrogen atom, at least two of which are nitrogen atoms, one of which is NH, and W ₁ to W ₇ form a condensed ring. m represents an integer greater than 1.]

[In General Formula X, X ₁ to X ₅ each independently represent a nitrogen atom or CR ₁ . R ₁ each independently represents a hydrogen atom, an aryl group, a heteroaryl group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an amino group, a cyano group, a thiol group, a carbonyl group, a halogeno group, a trifluoromethyl group, or a hydroxy group, It may also have a substituent.]

[In General Formula Y, Rn ₁ and Rn ₂ each independently represent an alkyl group. L represents a linking group. Y ₁ to Y ₅ each independently represent a carbon atom or a nitrogen atom, at least two of which are nitrogen atoms, one of which is NH, and Y ₁ to Y ₅ form a heterocycle. m represents an integer greater than 1.] It is a manufacturing method of a printed wiring board,
Having a process of applying the surface modifier according to any one of claims 1 to 8 on a metal layer to form a surface modification layer with a thickness of 15 nm or less.
A method of manufacturing a printed wiring board, characterized in that. The method of claim 9, wherein the surface modification layer has a thickness of 5 nm or less.
A method of manufacturing a printed wiring board, characterized in that. The method of claim 9, wherein the metal layer is a layer containing copper or a copper alloy as a main component.
A method of manufacturing a printed wiring board, characterized in that.

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