KR102404620B1 - Method for manufacturing micro etchant and wiring board - Google Patents

Abstract

The present invention is an acidic aqueous solution containing an inorganic acid, a cupric ion source, a halide ion source, and a polymer as a micro-etching agent for copper used for surface roughening of copper, wherein the polymer has an amino group or a quaternary It is a water-soluble polymer having an ammonium group-containing weight average molecular weight of 1000 or more, and when the molar concentration of the sulfate ion source is Cs (mol/L) and the molar concentration of the halide ion source is Ch (mol/L), 0 ≤ (Cs /Ch) ? 0.004, and the molar concentration of the halide ion source is 3.875 times or less of the molar concentration of the cupric ion source.

Description

Method for manufacturing micro etchant and wiring board

The present invention relates to a copper microetchant used for surface roughening of copper, and a method for manufacturing a wiring board.

A general multilayer wiring board is manufactured by laminating an inner-layer substrate having a conductive layer made of copper or a copper alloy or the like with another inner-layer substrate, copper foil, or the like via a prepreg. The conductive layers are electrically connected by a through hole called a through hole in which the hole wall is plated with copper. In order to improve the adhesiveness between a conductive layer and resin, such as a prepreg, or solder, the method of forming the fine uneven|corrugated shape on the surface of a conductive layer with a micro-etching agent (roughening agent) is used. When the microetchant is brought into contact with the metal surface, concavo-convex shapes are formed due to the difference in etching rate depending on the crystal orientation of the metal crystal grains or the difference in the etching rate between the metal crystal grains and the grain boundary portion, and the surface is roughened.

As microetchants for copper or copper alloys, organic acid microetchants (refer to Patent Literature 1), sulfuric acid-hydrogen peroxide microetchants (refer to Patent Literature 2), hydrochloric acid microetchants (refer to Patent Literature 3), etc. are known. have. Halogen, a polymer, a corrosion inhibitor, surfactant, etc. are added to these microetchants for the purpose of a roughening shape, adjustment of an etching rate, etc. Moreover, as a microetchant of copper or a copper alloy, the acidic aqueous solution containing an inorganic acid, a cupric ion source, a halide ion source, a sulfate ion source, and a polymer is known (refer patent document 4).

Patent Document 1: Japanese Patent Laid-Open No. 9-41163 Patent Document 2: Japanese Patent Laid-Open No. 2002-47583 Patent Document 3: WO2007/024312 pamphlet Patent Document 4: Japanese Patent Laid-Open No. 2017-150069

As a conductive layer of a printed wiring board, although rolled copper foil and electrolytic copper foil are mainly used, rolled copper and electrolytic copper differ in the microscopic shape of the surface. Further, the crystal properties of the two are significantly different. For this reason, when the kind of copper foil differs, the roughening shape formed in the surface according to an etching process may differ. In particular, since a rolled copper foil has large crystal grains and high uniformity of crystal plane orientation, there exists a tendency for an uneven|corrugated shape to be difficult to form. For this reason, in the conventional microetching agent, although the roughening shape excellent in adhesiveness with resin can be uniformly formed in surface on the surface of electrolytic copper foil, about a rolled copper foil, when an appropriate roughening shape is not formed, In some cases, cotton unevenness occurred. In such a case, it is necessary to change the microetching agent to be used according to the kind of copper foil, and problems, such as process control becoming complicated, arise.

Although the technique described in the said patent document 4 exhibits the outstanding roughening function, as a result of the present inventors examining in depth, it became clear that there was room for further improvement, especially in terms of the roughening shape after the roughening process of a rolled copper foil.

In view of the above, in the present invention, the difference in the roughening shape due to the difference in the crystallinity of copper is particularly small, and for any of the electrolytic copper and the rolled copper, a roughened shape with very good adhesion to a resin or the like can be formed. An object of the present invention is to provide a micro etchant.

In order to develop a micro-etchant capable of forming a roughened shape even with a rolled copper foil with excellent adhesion to a resin, etc., in particular, the present inventors paid attention to the ratio between the molar concentration of the sulfate ion source and the molar concentration of the halide ion source. As a result, the optimum ratio was found and the present invention was completed.

The present invention is an acidic aqueous solution containing an inorganic acid, a cupric ion source, a halide ion source, and a polymer as a copper microetchant used for surface roughening of copper, wherein the polymer has an amino group or a fourth It is a water-soluble polymer having a weight average molecular weight of 1000 or more containing a quaternary ammonium group, and when the molar concentration of the sulfate ion source is Cs (mol/L) and the molar concentration of the halide ion source is Ch (mol/L), 0 ≤ (Cs/Ch) ≤ 0.004 relates to a micro etchant characterized in that. Meanwhile, "copper" in the present specification includes copper and copper alloys. Further, the "copper layer" also includes a copper wiring pattern layer.

The micro-etchant according to the present invention includes an inorganic acid, a cupric ion source, a halide ion source, and a polymer as essential components, and may include a sulfate ion source as an optional component, but the molar concentration of the sulfate ion source It is designed so that 0 ≤ (Cs/Ch) ≤ 0.004 when Cs (mol/L) and the molar concentration of the halide ion source are Ch (mol/L). As shown in a scanning electron microscope photograph to be described later, the copper layer whose surface has been roughened by contacting the designed micro-etchant has fine irregularities formed on the entire surface, and has a roughened shape with high uniformity in the surface.

In the microetchant, the molar concentration of the cupric ion source is preferably 0.01 to 2 mol/L. Moreover, in the said microetchant, it is preferable that the molar concentration of the said halide ion source is 0.05-5 mol/L. Further, in the microetchant, it is preferable that the polymer has a weight concentration of 0.0005 to 2 g/L.

Further, the present invention provides a method for manufacturing a wiring board including a copper layer, comprising: a roughening treatment step of roughening the surface of the copper layer by contacting the surface of the copper layer with the micro-etchant according to any one of the above It relates to a method of manufacturing a wiring board, comprising:

In the manufacturing method of the said wiring board, it is preferable that the surface of the surface of the said copper layer contact with the said micro-etching agent consists of rolled copper. Further, in the method for manufacturing a wiring board, in the roughening treatment step, a replenishment solution comprising an inorganic acid, a halide ion source, and an acidic aqueous solution containing a polymer is added to the microetchant, and the replenishment solution in the replenishment solution The polymer is preferably a water-soluble polymer having an amino group or a quaternary ammonium group in the side chain and having a weight average molecular weight of 1000 or more.

ADVANTAGE OF THE INVENTION According to this invention, the roughening shape which is very excellent in adhesiveness with resin etc. also about rolled copper can be formed uniformly.

1A is a scanning electron microscope photograph (photographing angle 45°, magnification 5000 times) of the surface of rolled copper roughened by the micro-etchant of Example 1. FIG.
Fig. 1B is a scanning electron micrograph (photographing angle of 45°, magnification of 5000) of the surface of the electrolytic copper roughened with the micro-etchant of Example 1;
Fig. 2A is a scanning electron micrograph (photographing angle of 45°, magnification of 5000) of the surface of rolled copper roughened with the micro-etchant of Example 2;
Fig. 2B is a scanning electron micrograph (photographing angle of 45°, magnification of 5000) of the surface of the electrolytic copper roughened with the micro-etchant of Example 2;
3A is a scanning electron micrograph (photographing angle 45°, magnification 5000 times) of the surface of rolled copper roughened with the micro-etchant of Example 3. FIG.
Fig. 3B is a scanning electron micrograph (photographing angle of 45°, magnification of 5000) of the surface of the electrolytic copper roughened with the micro-etchant of Example 3;
Fig. 4A is a scanning electron micrograph (photographing angle of 45°, magnification of 5000) of the surface of rolled copper roughened by the micro-etchant of Example 4;
Fig. 4B is a scanning electron micrograph (photographing angle of 45°, magnification of 5000) of the surface of the electrolytic copper roughened with the micro-etchant of Example 4;
Fig. 5A is a scanning electron micrograph (photographing angle of 45°, magnification of 5000) of the surface of rolled copper roughened with the micro-etchant of Example 5;
Fig. 5B is a scanning electron micrograph (photographing angle of 45°, magnification of 5000) of the surface of the electrolytic copper roughened with the micro-etchant of Example 5;
6A is a scanning electron micrograph (photographing angle 45°, magnification 5000 times) of the surface of rolled copper roughened by the micro-etchant of Example 6. FIG.
Fig. 6B is a scanning electron micrograph (photographing angle of 45°, magnification of 5000) of the surface of the electrolytic copper roughened with the micro-etchant of Example 6.
Fig. 7A is a scanning electron micrograph (photographing angle of 45°, magnification of 5000) of the surface of rolled copper roughened with the micro-etchant of Example 7;
Fig. 7B is a scanning electron micrograph (photographing angle of 45°, magnification of 5000) of the surface of the electrolytic copper roughened by the micro-etchant of Example 7;
Fig. 8A is a scanning electron micrograph (photographing angle 45°, magnification 5000 times) of the surface of rolled copper roughened with the micro-etchant of Example 8;
Fig. 8B is a scanning electron microscope photograph (photographing angle of 45°, magnification of 5000) of the surface of the electrolytic copper roughened with the micro-etchant of Example 8;
Fig. 9 is a scanning electron microscope photograph (photographing angle of 45°, magnification of 5000) of the surface of rolled copper roughened with the micro-etchant of Example 9;
Fig. 10 is a scanning electron micrograph (photographing angle of 45°, magnification of 5000) of the surface of rolled copper roughened with the micro-etchant of Example 10;
Fig. 11 is a scanning electron microscope photograph (photographing angle of 45°, magnification of 5000) of the surface of rolled copper roughened with the micro-etchant of Example 11;
Fig. 12 is a scanning electron micrograph (photographing angle of 45°, magnification of 5000) of the surface of rolled copper roughened with the micro-etchant of Example 12;
Fig. 13 is a scanning electron micrograph (photographing angle of 45°, magnification of 5000) of the surface of rolled copper roughened with the micro-etchant of Example 13;
Fig. 14 is a scanning electron micrograph (photographing angle of 45°, magnification of 5000) of the surface of rolled copper roughened with the micro-etchant of Example 14;
Fig. 15A is a scanning electron micrograph (photographing angle of 45°, magnification of 5000) of the surface of rolled copper roughened with the micro-etchant of Comparative Example 1.
Fig. 15B is a scanning electron micrograph (photographing angle of 45°, magnification of 5000) of the surface of the electrolytic copper roughened with the micro-etchant of Comparative Example 1.
16A is a scanning electron micrograph (photographing angle 45°, magnification 5000 times) of the surface of rolled copper roughened with the micro-etchant of Comparative Example 2. FIG.
Fig. 16B is a scanning electron microscope photograph (photographing angle of 45°, magnification of 5000) of the surface of the electrolytic copper roughened with the micro-etchant of Comparative Example 2.
Fig. 17 is a scanning electron micrograph (photographing angle of 45°, magnification of 5000) of the surface of the rolled copper roughened with the micro-etchant of Comparative Example 3;
Fig. 18 is a scanning electron micrograph (photographing angle of 45°, magnification of 5000) of the surface of rolled copper roughened with the micro-etchant of Comparative Example 4.
19A is a scanning electron micrograph (photographing angle 45°, magnification 5000 times) of the surface of rolled copper roughened with the micro-etchant of Comparative Example 5;
19B is a scanning electron microscope photograph (photographing angle of 45°, magnification of 5000) of the surface of the electrolytic copper roughened with the micro-etchant of Comparative Example 5;
Fig. 20 is a scanning electron micrograph (photographing angle of 45°, magnification of 5000) of the surface of rolled copper roughened with the micro-etchant of Comparative Example 6.
Fig. 21 is a scanning electron micrograph (photographing angle of 45°, magnification of 5000) of the surface of rolled copper roughened with the micro-etchant of Comparative Example 7.
Fig. 22A is a scanning electron micrograph (photographing angle of 45°, magnification of 5000) of the surface of rolled copper roughened with the micro-etchant of Comparative Example 8;
22B is a scanning electron microscope photograph (photographing angle 45°, magnification 5000 times) of the surface of the electrolytic copper roughened with the micro-etchant of Comparative Example 8;
Fig. 23A is a scanning electron micrograph (photographing angle of 45°, magnification of 5000) of the surface of rolled copper roughened with the micro-etchant of Comparative Example 9;
Fig. 23B is a scanning electron microscope photograph (photographing angle of 45°, magnification of 5000) of the surface of the electrolytic copper roughened with the micro-etchant of Comparative Example 9;

The micro-etching agent of this invention is used in order to form a roughening shape on the surface of copper. The microetchant is an acidic aqueous solution containing an inorganic acid, a cupric ion source, a halide ion source, and a polymer as essential components, and may contain a sulfate ion source as an optional component, but the content of the sulfate ion source is reduced It is characterized in that it is designed within a specific range in relation to the ion source. Hereinafter, each component contained in the micro etchant of this invention is demonstrated.

<Copper Ion>

The cupric ion source is to generate cupric ions in an aqueous solution. The cupric ions act as an oxidizing agent for oxidizing copper. Examples of the cupric ion source include copper halides such as cupric chloride and cupric bromide; Inorganic acid salts, such as cupric sulfate and cupric nitrate; organic acid salts such as cupric formate and cupric acetate; cupric hydroxide; Cupric oxide etc. are mentioned. Since cupric halide produces cupric ions and halide ions in aqueous solution, it can be used as a thing having both a halide ion source and a cupric ion source. On the other hand, since cupric sulfate generates cupric ions, sulfate ions and hydrogen sulfate ions in aqueous solution, it can be used as a thing having both the action of a sulfate ion source and a cupric ion source, but its content is halide ion It needs to be designed within a certain range in relation to the circle. A cupric ion source can use 2 or more types together.

By increasing the concentration of the cupric ion source, the etching rate is maintained appropriately, and also for a copper layer having large copper crystal grains and high crystal plane orientation uniformity such as rolled copper, a uniform roughening shape over the entire surface. can be formed The molar concentration of the cupric ion source is preferably 0.01 mol/L or more. On the other hand, the molar concentration of the cupric ion source is the molar concentration of copper atoms contained in the cupric ion source, and is equivalent to the concentration of the cupric ion in the etching agent. While suppressing excessive etching, the molar concentration of the cupric ion source is preferably 2 mol/L or less from the viewpoint of maintaining the solubility of copper ions when the copper ion concentration increases with the progress of etching. As for the molar concentration of a cupric ion source, 0.1-1 mol/L is more preferable, and its 0.2-0.7 mol/L is still more preferable.

<Inorganic acid>

An acid has a function of dissolving the copper oxidized by cupric ion in aqueous solution, and also has a function of pH adjustment. While the solubility of oxidized copper improves by making pH of a microetchant low, there exists a tendency for precipitation of the other component when the copper ion density|concentration in a liquid rises with advancing of etching to be suppressed. From the viewpoint of keeping the pH of the micro-etchant low, an inorganic acid is used as the acid. As an inorganic acid, hydrohalic acids, such as hydrochloric acid and hydrobromic acid, and strong acids, such as sulfuric acid and nitric acid, are preferable. Hydrohalic acid can be used as a halide ion source and one having an acid action. On the other hand, sulfuric acid can be used as one having both the action of a sulfate ion source and an acid, but its content needs to be designed within a specific range in relation to the halide ion source. Among hydrohalic acids, hydrochloric acid (hydrogen chloride solution) is preferable.

An acid can use 2 or more types together, and can also use an organic acid in addition to an inorganic acid. From a viewpoint of suppressing precipitation of the other component when cupric ion concentration rises and improving stability of an etching agent, 3 or less are preferable and, as for pH of a microetchant, 2 or less are more preferable. It is preferable to adjust the density|concentration of the inorganic acid of a micro etchant so that pH may become the said range.

<Halide ion>

The halide ion source is one that generates halide ions in aqueous solution. The halide ion assists the dissolution of copper and has a function of forming the surface of the copper layer excellent in adhesion. As a halide ion, a chloride ion, a bromide ion, etc. can be illustrated. Especially, a viewpoint of forming the roughening shape excellent in adhesiveness uniformly to a chloride ion is preferable. Two or more types of halide ions may be included.

Examples of the halide ion source include hydrohalic acids such as hydrochloric acid and hydrobromic acid; and metal salts such as sodium chloride, calcium chloride, potassium chloride, ammonium chloride, potassium bromide, sodium bromide, copper chloride, copper bromide, zinc chloride, iron chloride, and tin bromide. A halide ion source can use 2 or more types together. As described above, the hydrohalic acid has both the functions of a halide ion source and an acid, and the copper halide has both a halide ion source and a cupric ion source.

From the viewpoint of promoting the formation of the roughened shape on the surface of the copper layer, the concentration of the halide ion in the microetchant, that is, the concentration of the halide ion ionized in the etchant, is preferably 0.05 mol/L or more. Although the upper limit in particular of the halide ion concentration is not restrict|limited, From a solubility viewpoint, 5 mol/L or less is preferable. As for the density|concentration of a halide ion, 0.5-3 mol/L is more preferable, and its 0.8-2 mol/L is still more preferable.

The molar concentration of the halide ion source is preferably 3 times or less of the molar concentration of the cupric ion source, and more preferably 1 to 3 times the molar concentration of the cupric ion source. By adjusting the concentration ratio between the halide ion source and the cupric ion source, a uniform roughened shape excellent in adhesion to a resin or the like tends to be easily formed with respect to both the electrolytic copper and the rolled copper.

<Sulphate ion source>

The sulfate ion source is to generate sulfate ions (SO ₄ ^2- ) and/or hydrogen sulfate ions (HSO ₄ ^- ) in aqueous solution. Examples of the sulfate ion source include sulfates such as potassium sulfate, sodium sulfate, calcium sulfate, magnesium sulfate, cupric sulfate (copper (II) sulfate), ferric sulfate, ammonium sulfate, sulfuric acid, sodium hydrogen sulfate, and the like. have. As described above, cupric sulfate has both the action of a sulfate ion source and a cupric ion source, and sulfuric acid has both the action of a sulfate ion source and an acid.

By the presence of sulfate ions and hydrogen sulfate ions, the pH in the liquid can be kept low and the stability of the aqueous solution can be improved. However, in the present invention, even when any of electrolytic copper and rolled copper is subjected to a roughening treatment, in order to obtain a roughened shape extremely excellent in adhesion to resin or the like, the molar concentration Cs (mol/L) of the sulfate ion source is reduced to halogen In relation to the molar concentration Ch (mol/L) of the cargo ion source, it is necessary to design in a specific range, specifically 0 ? (Cs/Ch) ? 0.004.

When (Cs/Ch) = 0, even if it is a case where any of electrolytic copper and rolled copper is roughened, the roughening shape excellent in adhesiveness with resin etc. can be obtained. Moreover, even if it is 0<(Cs/Ch)<=0.004, the roughening shape very excellent in the adhesiveness between electrolytic copper and rolled copper, resin, etc. can be obtained.

In the present invention, further by optimizing the molar concentration of the sulfate ion source in relation to the concentration of the cupric ion source, even when any of electrolytic copper and rolled copper is subjected to a roughening treatment, the roughness excellent in adhesion to resin, etc. A cotton shape can be obtained. When the concentration of the cupric ion source is Cco (mol/L), it is preferable to design 0 ≤ (Cs/Cco) ≤ 0.012. On the other hand, even if it is (Cs/Cco)=0, even if it is 0<(Cs/Ch)<=0.012, the roughening shape very excellent in the adhesiveness between electrolytic copper, rolled copper, resin, etc. can be obtained.

<Polymer>

The micro-etching agent of this invention contains the water-soluble polymer which has an amino group or a quaternary ammonium group in a side chain, and has a weight average molecular weight of 1000 or more. A polymer has the effect|action which forms the roughening shape excellent in adhesiveness with a halide ion. When a halide ion and the polymer which has an amino group or a quaternary ammonium group in a side chain coexist in a microetchant, fine unevenness|corrugation can be formed uniformly on the surface of rolled copper. From a viewpoint of forming a uniform roughening shape, 2000 or more are preferable and, as for the weight average molecular weight of a polymer, 5000 or more are more preferable. From a water-soluble viewpoint, 5 million or less are preferable and, as for the weight average molecular weight of a polymer, 2 million or less are more preferable. A weight average molecular weight is a value obtained by converting into polyethylene glycol by gel permeation chromatography (GPC) analysis.

As a polymer which has a quaternary ammonium group in a side chain, the polymer which has a repeating unit represented, for example by following formula (I) is mentioned.

In Formula (I), R ¹ to R ³ are each independently a chain or cyclic hydrocarbon group that may have a substituent, and two or more of R ¹ to R ³ may be bonded to each other to form a cyclic structure. . R ⁴ is a hydrogen atom or a methyl group, X ¹ is a single bond or a divalent linking group, and Y ⁻ is a counter anion.

As a specific example of the polymer which has a repeating unit represented by Formula (I), a quaternary ammonium salt type styrene polymer, a quaternary ammonium salt type aminoalkyl (meth)acrylate polymer, etc. are mentioned.

The polymer having a quaternary ammonium group in the side chain may have a repeating unit in which a carbon atom in the main chain and a quaternary ammonium group in the side chain form a cyclic structure so as to be represented by the following formula (II).

In Formula (II), R ⁵ and R ⁶ are a chain or cyclic hydrocarbon group which may have a substituent, and R ⁵ and R ⁶ may be bonded to each other to form a cyclic structure. m is an integer from 0 to 2. X ² and X ³ are each independently a single bond or a divalent linking group. As a specific example of the polymer which has a repeating unit of Formula (II), the quaternary ammonium salt type diallylamine polymer obtained by superposition|polymerization of the diallyldialkylammonium salt represented by Formula (IIa) is mentioned.

In the formula (IIa), R ⁷ and R ⁸ are each independently a hydrogen atom or a chain or cyclic hydrocarbon group which may have a substituent, preferably a hydrogen atom.

The quaternary ammonium group of the side chain may have a double bond between the nitrogen atom and the carbon atom, and the nitrogen atom of the quaternary ammonium group may be included as a constituent atom of the ring. In addition, two polymer chains may be bridge|crosslinked by a quaternary ammonium group like a repeating unit represented by following formula (III).

In the above formula (III), X ⁴ to X ⁷ are each independently a single bond or a divalent linking group.

Examples of the counter anion Z ^- of the quaternary ammonium salt include Cl ^- , Br ^- , I ^- , ClO ₄ ^- , BF ₄ ^- , CH ₃ COO ^- , PF ₆ ^- , HSO ₄ ^- , C ₂ H ₅ SO ₄ ^- can When X ¹ to X ⁷ is a divalent linking group, specific examples thereof include a methylene group, an alkylene group having 2 to 10 carbon atoms, an arylene group, a -CONH-R- group, a -COO-R- group (provided that R is and a single bond, a methylene group, an alkylene group having 2 to 10 carbon atoms, or an ether group having 2 to 10 carbon atoms (which is an alkyloxyalkyl group).

As a polymer which has an amino group in a side chain, the polymer which has a repeating unit represented, for example by following formula (IV) is mentioned.

In Formula (IV), R ¹¹ and R ¹² are each independently a hydrogen atom or a chain or cyclic hydrocarbon group which may have a substituent, and R ¹¹ and R ¹² may be bonded to each other to form a cyclic structure . R ¹³ is a hydrogen atom or a methyl group, and X ¹¹ is a single bond or a divalent linking group. The amino group may be any of primary, secondary, and tertiary, and may also form an ammonium salt. Examples of the counter anion of the ammonium salt include those described above as the counter anion Z ⁻ of the quaternary ammonium salt.

The polymer having an amino group in the side chain may have a repeating unit in which a carbon atom in the main chain and an amino group in the side chain form a cyclic structure, as represented by the following formula (V).

In the formula (V), R ¹⁴ is a hydrogen atom or a chain or cyclic hydrocarbon group which may have a substituent. m is an integer from 0 to 2. X ¹² and X ¹³ are each independently a single bond or a divalent linking group. As a specific example of the polymer which has a repeating unit of Formula (V), the diallylamine polymer obtained by superposition|polymerization of diallylamine or a diallylamine salt is mentioned.

When X ¹¹ to X ¹³ in the formulas (IV) and (V) are a divalent linking group, specific examples thereof include those described above as specific examples of X ¹ to X ⁷ .

The polymer including an amino group or a quaternary ammonium group in the side chain may be a copolymer. When the polymer is a copolymer, the copolymer may include a repeating unit containing an amino group or a quaternary ammonium group and a repeating unit containing neither an amino group nor a quaternary ammonium group. The arrangement of the repeating units in the copolymer is not particularly limited, and any of an alternating copolymer, a block copolymer, and a random copolymer may be used. When the copolymer is a block copolymer or a random copolymer, the ratio of the repeating unit containing an amino group or a quaternary ammonium group to the monomer units of the entire polymer is preferably 20 mol% or more, more preferably 30 mol% or more, , more preferably 40 mol% or more.

Examples of the repeating unit containing neither an amino group nor a quaternary ammonium group contained in the copolymer include structures derived from (meth)acrylic acid, (meth)alkyl acid alkyl, (meth)acrylic acid aminoalkyl, styrene derivative, sulfur dioxide, and the like. can The polymer having a structure derived from quaternary ammonium salt-type diallylamine represented by the general formula (II), and the polymer having a structure derived from diallylamine represented by the formula (IV) are the repeating copolymers. It is preferable to have a structural unit derived from sulfur dioxide represented by the following formula as a unit.

The polymer may have both an amino group and a quaternary ammonium group in the side chain. Moreover, a polymer can use 2 or more types together, and can also use together the polymer which has an amino group in a side chain, and the polymer which has a quaternary ammonium group in a side chain.

The concentration of the polymer in the microetchant is preferably 0.0005 to 2 g/L, more preferably 0.005 to 1 g/L, and furthermore 0.008 to 0.5 g/L from the viewpoint of forming the surface of the copper layer having excellent adhesion. It is preferred, and 0.01 to 0.2 g/L is particularly preferred.

<Other additives>

The micro-etching agent of this invention can be prepared by dissolving said each component in ion-exchange water etc. The micro etchant may contain components other than the above. For example, a nonionic surfactant as an antifoaming agent or a complexing agent such as pyridine may be added to improve copper dissolution stability. In addition, various additives can be added as needed. When adding an additive, the concentration of the additive in the micro-etchant is preferably about 0.0001 to 20% by weight.

When hydrogen peroxide is contained in the micro-etchant, copper dissolution by the oxidizing power of hydrogen peroxide advances, so the formation of a roughening shape in a copper layer with large copper crystal grains and high crystal plane orientation uniformity like rolled copper is hindered. there may be cases In addition, since it does not contain hydrogen peroxide, there is also an advantage that the concentration management of the solution and the waste liquid treatment can be simplified. For this reason, it is most preferable that the hydrogen peroxide concentration in a microetchant is 0. On the other hand, mixing of a trace amount of hydrogen peroxide contained in the raw material, etc. may be allowed. 0.1 weight% or less is preferable and, as for the hydrogen peroxide concentration of a micro etching agent, 0.01 weight% or less is more preferable.

[Use of micro etchant]

Said micro etchant can be widely used for roughening of the surface of a copper layer. Fine irregularities are uniformly formed on the surface of the treated copper layer, and adhesion to resins such as prepregs, plating resists, etching resists, soldering resists, electrodeposition resists and coverlays is good. Further, since the surface is excellent in solderability, it is particularly useful for manufacturing various wiring boards including those for pin grid arrays (PGAs) and ball grid arrays (BGAs). Moreover, it is useful also for the surface treatment of a lead frame.

The microetchant of the present invention has a small difference in the roughening shape due to the difference in the crystallinity of copper, and can form a roughened shape excellent in adhesion to a resin or the like for any of electrolytic copper and rolled copper. For this reason, even when the copper foil of a process object differs, it is not necessary to replace|exchange an etching agent, and the same etching agent can be used repeatedly.

[Method for manufacturing wiring board]

In manufacture of a wiring board, the surface of copper is roughened by making the surface of a copper layer contact the microetching agent mentioned above. When manufacturing a wiring board including a plurality of copper layers, only one of the plurality of copper layers may be treated with the micro-etchant, and two or more copper layers may be treated with the micro-etchant. While the conventional micro-etching agent is mainly used for surface roughening of an electrolytic copper foil, the above-mentioned micro-etching agent can form a uniform roughening shape on the surface also about any of electrolytic copper and rolled copper. For this reason, the micro-etching agent of this invention can be used suitably also for roughening of the copper layer which the surface of to-be-processed surface (surface made to contact with a micro-etching agent) consists of rolled copper.

In the roughening treatment, the method of bringing the microetchant into contact with the surface of the copper layer is not particularly limited, and for example, a method of spraying a microetchant on the surface of the copper layer to be treated or microetching the copper layer to be treated The method of being immersed in an agent, etc. are mentioned. In the case of spraying, it is preferable to set the temperature of the micro-etchant to 10 to 40°C, and to etch at a spray pressure of 0.03 to 0.3 MPa for 5 to 120 seconds. In the case of immersion, it is preferable to set the temperature of the microetchant to 10 to 40°C, and to etch under the conditions for 5 to 120 seconds. On the other hand, in the case of immersion, it is preferable to blow air into the microetchant by bubbling or the like in order to oxidize the cuprous ions generated in the microetchant by copper etching to cupric ions. When the microetchant does not substantially contain hydrogen peroxide, it is easy to treat the waste liquid after use, and can be treated by a general simple method using, for example, neutralization and a polymer coagulant.

Although the etching amount in a roughening process is not specifically limited, From a viewpoint of forming a uniform uneven|corrugated shape irrespective of copper crystallinity, 0.05 micrometer or more is preferable, and 0.1 micrometer or more is more preferable. When the etching amount is excessively large, problems such as disconnection due to complete etching of the copper layer or increase in resistance due to a decrease in the cross-sectional area of wiring may occur. For this reason, 5 micrometers or less are preferable and, as for etching amount, 3 micrometers or less are more preferable. On the other hand, "etched amount" refers to the average etching amount (dissolved amount) in the depth direction, and is calculated from the weight, specific gravity, and front projection area of the copper surface of copper dissolved by the micro etchant.

After the roughening treatment step, in order to remove the generated smut, it is preferable to wash the surface of the roughened copper layer with an acidic aqueous solution. As an acidic aqueous solution used for washing|cleaning, hydrochloric acid, sulfuric acid aqueous solution, nitric acid aqueous solution, etc. can be used. Hydrochloric acid is preferable because it has little influence on the roughening shape and also has high smut removability. From a viewpoint of smut removability, 0.3 to 35 weight% is preferable and, as for the acid concentration of an acidic aqueous solution, 1 to 10 weight% is more preferable. The washing|cleaning method is not specifically limited, The method of spraying an acidic aqueous solution on the roughened copper layer surface, the method of immersing the roughened copper layer in an acidic aqueous solution, etc. are mentioned. When spraying, it is preferable to set the temperature of the acidic aqueous solution to 15 to 35°C, and to wash under the conditions of 3 to 30 seconds at a spray pressure of 0.03 to 0.3 MPa. In the case of immersion, it is preferable to set the temperature of the acidic aqueous solution to 15 to 35°C, and to wash under the conditions for 3 to 30 seconds.

When using a microetchant continuously, it is preferable to roughen, adding a replenishment liquid. By performing a roughening process, adding a replenishment liquid, the density|concentration of each component in the micro-etching agent in a process can be maintained appropriately. The replenishment liquid is an aqueous solution containing an inorganic acid, a cupric ion source, a halide ion source, and the polymer. The addition amount of the replenishment liquid and the timing of the addition of the replenishment liquid can be appropriately set according to the concentration control range of each component and the like. Each component in the replenishment liquid is similar to the component contained in the micro-etchant described above. The concentration of each component in the replenishment solution is appropriately adjusted according to the initial concentration of the microetchant used for the treatment, and the like.

After the treatment with the microetchant, in order to further improve adhesion to the resin, it can be treated with an aqueous solution of azoles or an alcohol solution. Further, after the treatment with the microetchant, oxidation treatment called brown oxide treatment or black oxide treatment may be performed.

[Example]

Next, Examples of the present invention will be described together with Comparative Examples. On the other hand, the present invention is not interpreted as being limited to the following examples.

<Processing with micro-etchant>

As a test board|substrate, the base material which has rolled copper foil (JX metal, HA foil) was prepared. Each of these substrates was sprayed on the copper foil of the test substrate under a spray pressure of 0.1 MPa using each micro-etchant (30 ° C.) shown in Table 1, and the etching time was adjusted so that the etching amount of copper was 1.0 μm. Etched. Then, it washed with water, and the etching-treated surface was immersed in hydrochloric acid (hydrogen chloride concentration: 3.5 wt%) at a temperature of 25°C for 15 seconds. Thereafter, it was washed with water and dried.

In addition, as a test substrate, a glass fabric epoxy resin impregnated copper clad laminate (Hitachi Kasei, product name: MCL-E-67, 10 cm × 10 cm, thickness 0.2 mm) with an electrolytic copper foil having a thickness of 35 μm on both sides of an insulating substrate was placed on it. Etching, acid washing, washing with water and drying were carried out in the same manner as above, using the test substrate with 18 μm copper plating, and using the etching agents of Examples 1 to 8 and Comparative Examples 1 to 2, 5, and 8 to 9. carried out.

The details of polymers A to D shown in Tables 1 and 2 are as follows. These polymers were used so that the polymer concentration in an etching agent might become the compounding quantity shown in Table 1. Remainder of the compounding component of each etching agent shown in Table 1 and Table 2 is ion-exchange water.

Polymer A: Diallyldialkylammonium (quaternary ammonium) hydrochloride/sulfur dioxide alternating copolymer having the following repeating units (weight average molecular weight about 5000)

Polymer B: Diallylamine (secondary amine) hydrochloride/sulfur dioxide alternating copolymer having the following repeating units (weight average molecular weight about 5000)

Polymer C: Diallylamine (secondary amine) acetate/sulfur dioxide alternating copolymer having the following repeating units (weight average molecular weight about 5000)

Polymer D: Vinylpyrrolidone/N,N-dimethylaminoethylmethacrylamidediethylsulfate random copolymer having the following structure (weight average molecular weight about 800,000)

<Evaluation of uniformity of roughening by scanning electron microscope observation>

The surface of the copper layer of the test board|substrate after the said process was observed with the scanning electron microscope (SEM) (model JSM-7000F, Nippon Denshi Corporation). SEM observation images are shown in FIGS. 1 to 23 . Tables 1 and 2 show correspondences between Examples and Comparative Examples and SEM observation images. In Table 1 and Table 2, the rating of the roughening shape of the rolled copper surface according to the following reference|standard is also shown together.

<Evaluation criteria>

1: No unevenness is formed on the surface

2: Concave-convex formed on the surface but not roughened

3: Concave-convex is formed on the surface and is roughened, but the unevenness is large and there is roughening unevenness

4: A thing in which fine irregularities are formed on the entire surface

5: Fine unevenness is formed on the entire surface, and uniformity in the surface is high

When the micro-etching agent which concerns on Examples 1-14 is used for a roughening process, it turns out that the uniform roughening shape is formed in the surface of both rolled copper and electrolytic copper. In particular, in rolled copper, as Table 1 shows, it turns out that evaluation criteria are also generally high.

On the other hand, since the microetchant which concerns on the comparative example 1 is (Cs/Ch)=0.0042, when this is used for a roughening process, it turns out that a roughening shape is not favorable. Moreover, also about the microetching agent which concerns on Comparative Examples 2-5, since (Cs/Ch) is large, when these are used for a roughening process, it turns out that a roughening shape is not favorable.

Moreover, since the micro-etching agent which concerns on Comparative Examples 6-7 and 9 does not have a halide ion source, when these are used for a roughening process, it turns out that a roughening shape is not favorable.

Moreover, since the micro-etching agent which concerns on the comparative example 8 uses not an inorganic acid but an organic acid, when this is used for a roughening process, it turns out that a roughening shape is not favorable.

Claims (7)

As a copper microetchant used for surface roughening of copper,
an acidic aqueous solution containing an inorganic acid, a cupric ion source, a halide ion source, and a polymer;
It may include a sulfate ion source as the inorganic acid,
The polymer is a water-soluble polymer having a weight average molecular weight of 1000 or more including an amino group or a quaternary ammonium group in a side chain,
When the molar concentration of the sulfate ion source is Cs (mol/L) and the molar concentration of the halide ion source is Ch (mol/L), 0 ≤ (Cs/Ch) ≤ 0.004,
The molar concentration of the halide ion source is 1 to 3.875 times the molar concentration of the cupric ion source, the micro-etchant. According to claim 1,
The molar concentration of the cupric ion source is 0.01 to 2 mol/L, micro-etchant. 3. The method of claim 1 or 2,
The molar concentration of the halide ion source is 0.05 to 5 mol/L, micro etchant. According to claim 1,
The weight concentration of the polymer is 0.0005 to 2 g / L, micro etchant. A method of manufacturing a wiring board including a copper layer, the method comprising:
A method of manufacturing a wiring board, comprising a roughening treatment step of roughening the surface of the copper layer by contacting the surface of the copper layer with the micro-etchant of claim 1 . 6. The method of claim 5,
The method of manufacturing a wiring board, wherein the surface of the copper layer in contact with the micro-etchant is made of rolled copper. 6. The method of claim 5,
In the roughening treatment step, a replenishment solution consisting of an inorganic acid, a halide ion source, and an acidic aqueous solution containing a polymer is added to the micro-etchant,
The method for manufacturing a wiring board, wherein the polymer in the replenishment solution is a water-soluble polymer having an amino group or a quaternary ammonium group in a side chain and having a weight average molecular weight of 1000 or more.

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