CN113170585B

CN113170585B - Microetching agent and method for producing wiring board

Info

Publication number: CN113170585B
Application number: CN202080005956.4A
Authority: CN
Inventors: 松本启佑; 谷口真依; 四辻智美; 漆畑薰
Original assignee: MEC Co Ltd
Current assignee: MEC Co Ltd
Priority date: 2020-06-02
Filing date: 2020-12-14
Publication date: 2023-04-04
Anticipated expiration: 2040-12-14
Also published as: KR102404620B1; KR20210151835A; CN113170585A

Abstract

The microetching agent is a copper microetching agent for roughening the surface of copper, and is an acidic aqueous solution containing an inorganic acid, a copper (II) ion source, a halide ion source, and a polymer, wherein the polymer is a water-soluble polymer having a weight-average molecular weight of 1000 or more and containing an amino group or a quaternary ammonium group in a side chain, the molar concentration of the sulfate ion source is 0 to 0.004, and the molar concentration of the halide ion source is 3.875 times or less the molar concentration of the copper (II) ion source, wherein Cs (mol/L) is the molar concentration of the sulfate ion source, and Ch (mol/L) is the molar concentration of the halide ion source.

Description

Microetching agent and method for producing wiring board

Technical Field

The present invention relates to a copper microetching agent for roughening a copper surface and a method for manufacturing a wiring board.

Background

Generally, a multilayer wiring board is manufactured by laminating and pressing an inner layer substrate having a conductive layer made of copper, a copper alloy, or the like, with another inner layer substrate, a copper foil, or the like, via a prepreg. The conductive layers are electrically connected to each other through via holes, which are plated with copper on the walls of the via holes and are called through holes. In order to improve the adhesion between the conductive layer and a resin such as a prepreg or a solder, a method of forming a fine uneven shape on the surface of the conductive layer by using a microetching agent (roughening agent) is used. When the metal surface is brought into contact with the microetching agent, the surface is roughened by forming irregularities due to a difference in etching rate caused by the crystal orientation of the metal crystal grains or a difference in etching rate between the metal crystal grains and the grain boundary portion.

As microetching agents for copper or copper alloys, organic acid type microetching agents (see patent document 1), sulfuric acid-hydrogen peroxide type microetching agents (see patent document 2), hydrochloric acid type microetching agents (see patent document 3), and the like are known. These microetching agents are added with halogen, polymer, anticorrosive agent, surfactant, and the like in order to adjust the roughened shape, etching rate, and the like. Further, as a microetching agent for copper or a copper alloy, an acidic aqueous solution containing an inorganic acid, a copper (II) ion source, a halide ion source, a sulfate ion source, and a polymer is known (see patent document 4).

[ Prior art documents ]

[ patent document ]

Patent document 1: japanese patent laid-open publication No. 9-41163

Patent document 2: japanese patent laid-open publication No. 2002-47583

Patent document 3: specification of WO2007/024312

Patent document 4: japanese laid-open patent publication No. 2017-150069

Disclosure of Invention

[ problem to be solved by the invention ]

As the conductive layer of the printed wiring board, a rolled copper foil and an electrolytic copper foil are mainly used, but the rolled copper and the electrolytic copper have different surface microscopic shapes. In addition, the two copper species also have a large difference in their crystallographic characteristics. Therefore, if the copper foil is different in type, the roughened shape formed on the surface by the etching treatment may be different. In particular, since the rolled copper foil has large crystal grains and high uniformity of crystal plane orientation, it tends to be difficult to form a concave-convex shape. Therefore, although the roughened shape excellent in adhesion to the resin can be uniformly formed in the upper surface of the electrolytic copper foil by the microetching agent of the related art, the rolled copper foil may not be formed into an appropriate roughened shape or may have unevenness in roughening. In this case, the microetching agent used needs to be changed depending on the type of the copper foil, and therefore, there is a problem that the process control becomes complicated.

Although the technique described in patent document 4 exhibits an excellent roughening function, the present inventors have conducted extensive studies and have found that there is room for further improvement in the roughened shape of a rolled copper foil after roughening treatment.

In view of the above circumstances, an object of the present invention is to provide a microetching solution which has extremely small difference in roughened shape due to difference in crystallinity of copper and can form a roughened shape having extremely excellent adhesion to a resin or the like for both electrolytic copper and rolled copper.

[ means for solving the problems ]

The present inventors have studied the ratio of the molar concentration of a sulfate ion source to the molar concentration of a halide ion source, and found the optimum ratio, in order to develop a microetching agent capable of forming a roughened shape having extremely excellent adhesion to a resin or the like even for a rolled copper foil, and have completed the present invention.

The invention relates to a microetching agent for copper, which is used for roughening the surface of copper, and is characterized in that the microetching agent is an acidic aqueous solution containing an inorganic acid, a copper (II) ion source, a halide ion source and a polymer, wherein the polymer is a water-soluble polymer having a weight-average molecular weight of 1000 or more and containing an amino group or a quaternary ammonium group in a side chain, 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), the Cs/Ch is 0 to 0.004. In addition, "copper" in the present specification includes copper and copper alloys. Further, the "copper layer" also includes a copper wiring pattern layer.

The microetching agent of the present invention comprises an inorganic acid, a copper (II) ion source, a halide ion source, and a polymer as essential components, and may further comprise a sulfate ion source as optional components, and is designed so that 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. Ltoreq. Cs/Ch.ltoreq.0.004 is provided. The copper layer having a roughened surface by contacting with the microetching agent designed in this manner has fine irregularities formed on the entire surface and a roughened shape having high in-plane uniformity, as shown in a scanning electron micrograph described below.

In the microetching solution, the molar concentration of the copper (II) ion source is preferably 0.01 to 2 (mol/L). In the microetching solution, the halide ion source preferably has a molar concentration of 0.05 to 5 (mol/L). In the microetching solution, the weight concentration of the polymer is preferably 0.0005 to 2 (g/L).

The present invention also relates to a method for manufacturing a wiring board including a copper layer, the method including a roughening treatment step of bringing a surface of the copper layer into contact with the microetching agent according to any one of the above embodiments to roughen the surface of the copper layer.

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

[ technical effects of the invention ]

According to the present invention, even in rolled copper, a roughened shape having extremely excellent adhesion to a resin or the like can be uniformly formed.

Drawings

Fig. 1A is a scanning electron microscope photograph (45 ° angle and 5000 × magnification) of the rolled copper surface after roughening treatment with the microetching agent of example 1.

FIG. 1B is a scanning electron micrograph (at an angle of 45 ℃ and at a magnification of 5000X) of the surface of the electrolytic copper after roughening treatment with the microetching agent of example 1.

Fig. 2A is a scanning electron microscope photograph (45 ° angle, 5000 × magnification) of the rolled copper surface after roughening treatment with the microetching agent of example 2.

FIG. 2B is a scanning electron micrograph (at an angle of 45 ℃ and at a magnification of 5000X) of the surface of the electrolytic copper roughened with the microetching agent of example 2.

Fig. 3A is a scanning electron microscope photograph (45 ° angle, 5000 × magnification) of the rolled copper surface after roughening treatment with the microetching agent of example 3.

FIG. 3B is a scanning electron micrograph (at 45 ℃ angle and at 5000 Xmagnification) of the surface of the electrolytic copper roughened with the microetching agent of example 3.

Fig. 4A is a scanning electron microscope photograph (45 ° angle, 5000 × magnification) of the rolled copper surface after roughening treatment with the microetching agent of example 4.

FIG. 4B is a scanning electron micrograph (at an angle of 45 ℃ and at a magnification of 5000X) of the surface of the electrolytic copper after roughening treatment with the microetching agent of example 4.

Fig. 5A is a scanning electron microscope photograph (45 ° angle, 5000 × magnification) of the rolled copper surface after roughening treatment with the microetching agent of example 5.

FIG. 5B is a scanning electron micrograph (at an angle of 45 ℃ and at a magnification of 5000X) of the surface of the electrolytic copper after roughening treatment with the microetching agent of example 5.

Fig. 6A is a scanning electron micrograph (at 45 ° and at 5000 × magnification) of the rolled copper surface after roughening treatment with the microetching agent of example 6.

FIG. 6B is a scanning electron micrograph (at 45 ℃ angle and at 5000 Xmagnification) of the surface of the electrolytic copper roughened with the microetching agent of example 6.

Fig. 7A is a scanning electron microscope photograph (45 ° angle, 5000 × magnification) of the rolled copper surface after roughening treatment with the microetching agent of example 7.

FIG. 7B is a scanning electron micrograph (at an angle of 45 ℃ and at a magnification of 5000X) of the surface of the electrolytic copper after roughening treatment with the microetching agent of example 7.

Fig. 8A is a scanning electron microscope photograph (45 ° angle, 5000 × magnification) of the rolled copper surface after roughening treatment with the microetching agent of example 8.

FIG. 8B is a scanning electron micrograph (at 45 ℃ angle, 5000 times magnification) of an electrolytic copper surface roughened with the microetching agent of example 8.

FIG. 9 is a scanning electron micrograph (at an angle of 45 ℃ and at a magnification of 5000X) of a rolled copper surface after roughening treatment with the microetching agent of example 9.

FIG. 10 is a scanning electron micrograph (at an angle of 45 ℃ and at a magnification of 5000X) of a rolled copper surface after roughening treatment with the microetching agent of example 10.

FIG. 11 is a scanning electron micrograph (at an angle of 45 ℃ and at a magnification of 5000X) of a rolled copper surface roughened with the microetching agent of example 11.

Fig. 12 is a scanning electron microscope photograph (45 ° angle and 5000 × magnification) of the rolled copper surface after roughening treatment with the microetching agent of example 12.

FIG. 13 is a scanning electron micrograph (at an angle of 45 ℃ and at a magnification of 5000X) of a rolled copper surface after roughening treatment with the microetching agent of example 13.

FIG. 14 is a scanning electron microscope photograph (angle 45 ℃ and magnification 5000 times) of a rolled copper surface after roughening treatment with the microetching agent of example 14.

Fig. 15A is a scanning electron microscope photograph (45 ° angle and 5000 × magnification) of the rolled copper surface after roughening treatment with the microetching agent of comparative example 1.

FIG. 15B is a scanning electron micrograph (at an angle of 45 ℃ C. And at a magnification of 5000 ℃ C.) of the electrolytic copper surface after roughening treatment with the microetching agent of comparative example 1.

Fig. 16A is a scanning electron microscope photograph (angle of 45 ° and magnification of 5000 ×) of the rolled copper surface after roughening treatment with the microetching agent of comparative example 2.

FIG. 16B is a scanning electron micrograph (at an angle of 45 ℃ and at a magnification of 5000X) of the surface of the electrolytic copper after roughening treatment with the microetching agent of comparative example 2.

FIG. 17 is a scanning electron micrograph (at an angle of 45 ℃ and at a magnification of 5000X) of a rolled copper surface roughened with the microetching agent of comparative example 3.

FIG. 18 is a scanning electron microscope photograph (at an angle of 45 ℃ and a magnification of 5000X) of a rolled copper surface roughened with the microetching agent of comparative example 4.

Fig. 19A is a scanning electron microscope photograph (45 ° angle, 5000 × magnification) of the rolled copper surface after roughening treatment with the microetching agent of comparative example 5.

FIG. 19B is a scanning electron microscope photograph (45 ℃ angle. And 5000 Xmagnification) of the surface of the electrolytic copper after roughening treatment with the microetching agent of comparative example 5.

FIG. 20 is a scanning electron micrograph (at an angle of 45 ℃ C. And at a magnification of 5000 times) of a rolled copper surface roughened with the microetching agent of comparative example 6.

FIG. 21 is a scanning electron microscope photograph (at an angle of 45 ℃ and a magnification of 5000X) of a rolled copper surface roughened with the microetching agent of comparative example 7.

Fig. 22A is a scanning electron microscope photograph (45 ° angle and 5000 × magnification) of the rolled copper surface after roughening treatment with the microetching agent of comparative example 8.

FIG. 22B is a scanning electron micrograph (at an angle of 45 ℃ C. And at a magnification of 5000 times) of an electrolytic copper surface roughened with the microetching agent of comparative example 8.

Fig. 23A is a scanning electron microscope photograph (45 ° angle and 5000 × magnification) of the rolled copper surface after roughening treatment with the microetching agent of comparative example 9.

FIG. 23B is a scanning electron micrograph (at an angle of 45 ℃ C. And at a magnification of 5000 times) of an electrolytic copper surface after roughening treatment with the microetching agent of comparative example 9.

Detailed Description

The microetching agent of the present invention is used for forming a roughened shape on the surface of copper. The microetching agent is an acidic aqueous solution containing an inorganic acid, a copper (II) ion source, a halide ion source and a polymer as essential components, and may further contain a sulfate ion source as an optional component, but is characterized in that the content of the sulfate ion source is designed to be within a specific range based on the relationship with the halide ion source. Hereinafter, each component contained in the microetching agent of the present invention will be described.

< copper (II) ion >

The copper (II) ion source is a substance that generates copper (II) ions in an aqueous solution. Copper (II) ions function as an oxidizing agent for oxidizing copper. Examples of the copper (II) ion source include: copper halides such as copper (II) chloride and copper (II) bromide; inorganic acid salts such as copper (II) sulfate and copper (II) nitrate; organic acid salts such as copper (II) formate and copper (II) acetate; copper (II) hydroxide; copper (II) oxide, and the like. Since copper (II) halide generates copper (II) ions and halide ions in an aqueous solution, it can be used as a substance having the functions of a halide ion source and a copper (II) ion source. Further, since copper (II) sulfate generates copper (II) ions, sulfate ions and hydrogen sulfate ions in an aqueous solution, it can be used as a substance having the functions of a sulfate ion source and a copper (II) ion source, but its content must be designed within a specific range based on the relationship with a halide ion source. Two or more copper (II) ion sources may be used simultaneously.

By increasing the concentration of the copper (II) ion source, the etching rate can be appropriately maintained, and a uniform roughened shape can be formed on the entire surface of a copper layer having large copper crystal grains and high uniformity of crystal plane orientation, such as rolled copper. The molar concentration of the copper (II) ion source is preferably 0.01 (mol/L) or more. The molar concentration of the copper (II) ion source is equal to the molar concentration of copper atoms contained in the copper (II) ion source, and is equal to the concentration of copper (II) ions in the etchant. The molar concentration of the copper (II) ion source is preferably 2 (mol/L) or less in terms of suppressing over-etching and maintaining the solubility of copper ions when the copper ion concentration increases as etching proceeds. The molar concentration of the copper (II) ion source is more preferably 0.1 to 1 (mol/L), and still more preferably 0.2 to 0.7 (mol/L).

< inorganic acid >

The acid has a function of dissolving copper oxidized by copper (II) ions in an aqueous solution, and a function of adjusting pH. The following tendency is exhibited: by lowering the pH of the microetching solution, the solubility of oxidized copper can be improved, and the deposition of other components can be suppressed when the copper ion concentration in the solution increases as the etching proceeds. In terms of maintaining a low microetching agent pH, an inorganic acid is used as the acid. The inorganic acid is preferably a hydrohalic acid such as hydrochloric acid or hydrobromic acid, or a strong acid such as sulfuric acid or nitric acid. The halogen acid can be used as a substance having the function of a halide ion source and an acid. Further, sulfuric acid can be used as a substance having the functions of a sulfate ion source and an acid, but its content must be designed within a specific range based on the relationship with a halide ion source. Among the halogen acids, hydrochloric acid (aqueous hydrogen chloride solution) is preferable.

Two or more kinds of acids may be used at the same time, and in addition to the inorganic acid, an organic acid may be used. The pH of the microetching solution is preferably 3 or less, more preferably 2 or less, from the viewpoint of suppressing precipitation of other components when the copper (II) ion concentration is increased to improve the stability of the etching solution. The concentration of the inorganic acid of the microetching agent is preferably adjusted in such a manner that the pH is within the range.

< halide ion >

A halide ion source is a substance that generates halide ions in an aqueous solution. The halide ion has a function of assisting the dissolution of copper to form a copper layer surface excellent in adhesion. Examples of the halide ion include chloride ion and bromide ion. Among them, chloride ions are preferable in terms of uniformly forming a roughened shape excellent in adhesion. Two or more kinds of halide ions may be contained.

As the halide ion source, there can be mentioned: 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. Two or more halide ion sources may be used simultaneously. As described above, the hydrohalic acid has the functions of a halide ion source and an acid, and the copper halide has the functions of a halide ion source and a copper (II) ion source.

The concentration of halide ions in the microetching solution (i.e., the concentration of halide ions released in the etching solution) is preferably 0.05 (mol/L) or more in terms of promoting the formation of roughened shapes on the surface of the copper layer. The upper limit of the halide ion concentration is not particularly limited, but it is preferably 5 (mol/L) or less in terms of solubility. The concentration of the halide ion is more preferably 0.5 to 3 (mol/L), and still more preferably 0.8 to 2 (mol/L).

The molar concentration of the halide ion source is preferably 3 times or less, more preferably 1 to 3 times the molar concentration of the copper (II) ion source. By adjusting the concentration ratio of the halide ion source to the copper (II) ion source, it is likely that electrolytic copper and rolled copper will be formed into a uniform roughened shape having excellent adhesion to a resin or the like.

< sulfate ion Source >

The sulfate ion source is used for generating sulfate ions (SO) in aqueous solution ₄ ^2- ) And/or hydrogen sulfate ions (HSO) ₄ ^- ) The substance (1). As the sulfate ion source, there can be mentioned: sulfates such as potassium sulfate, sodium sulfate, calcium sulfate, magnesium sulfate, copper sulfate (II), iron sulfate (III), and ammonium sulfate; or sulfuric acid, sodium bisulfate, and the like. As described above, copper (II) sulfate has the functions of a sulfate ion source and a copper (II) ion source, and sulfuric acid has the functions of a sulfate ion source and an acid.

The existence of sulfate ions and hydrogen sulfate ions can keep lower pH value in the solution, thereby improving the stability of the aqueous solution. In the present invention, when roughening treatment is performed on either electrolytic copper or rolled copper, the molar concentration Cs (mol/L) of the sulfate ion source must be designed to be in a specific range based on the relationship with the molar concentration Ch (mol/L) of the halide ion source, specifically, 0 ≦ Cs/Ch ≦ 0.004 in order to obtain a roughened shape having extremely excellent adhesion to a resin or the like.

When (Cs/Ch) =0, when any one of electrolytic copper and rolled copper is subjected to roughening treatment, a roughened shape extremely excellent in adhesion to a resin or the like can be obtained. Furthermore, even if 0 < (Cs/Ch) > 0.004 or less, a roughened shape extremely excellent in adhesion between electrolytic copper and rolled copper and a resin or the like can be obtained.

In the present invention, the molar concentration of the sulfate ion source is optimized based on the relationship with the concentration of the copper (II) ion source, and thus, when any one of electrolytic copper and rolled copper is subjected to roughening treatment, a roughened shape extremely excellent in adhesion to a resin or the like can be obtained. When the concentration of the copper (II) ion source is Cco (mol/L), it is preferably 0 to 0.012 (Cs/Cco). In addition, when (Cs/Cco) =0, 0 < (Cs/Ch) ≦ 0.012, a roughened shape extremely excellent in adhesion of electrolytic copper and rolled copper to a resin or the like can be obtained.

< Polymer >

The microetching agent of the present invention contains 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. The polymer has an effect of forming a roughened shape having excellent adhesion together with halide ions. By causing the microetching agent to contain both a halide ion and a polymer having an amino group or a quaternary ammonium group in a side chain, fine irregularities can be uniformly formed on the surface of rolled copper. The weight average molecular weight of the polymer is preferably 2000 or more, more preferably 5000 or more, from the viewpoint of forming uniform roughened shapes. From the viewpoint of water solubility, the weight average molecular weight of the polymer is preferably 500 ten thousand or less, and more preferably 200 ten thousand or less. The weight average molecular weight is a value obtained by analyzing by Gel Permeation Chromatography (GPC) in terms of polyethylene glycol.

Examples of the polymer having a quaternary ammonium group in a side chain include a polymer having a repeating unit represented by the following formula (I).

[ chemical formula 1]

In the formula (I), R ¹ ～R ³ Each independently is a chain or cyclic hydrocarbon group which may have a substituent, R ¹ ～R ³ Two or more of them may be bonded to each other to form a ring structure. R ⁴ Is a hydrogen atom or a methyl group, X ¹ Is a single bond or a divalent linking group, Y ^- Is a counter anion.

Specific examples of the polymer having a repeating unit represented by formula (I) include a quaternary ammonium salt type styrene polymer, a quaternary ammonium salt type aminoalkyl (meth) acrylate polymer, and the like.

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

[ chemical formula 2]

In the formula (II), R ⁵ And R ⁶ Is a chain or cyclic hydrocarbon group which may have a substituent, R ⁵ And R ⁶ May be bonded to each other to form a ring structure. m is an integer of 0 to 2. X ² And X ³ Each independently a single bond or a divalent linking group. Specific examples of the polymer having the repeating unit of formula (II) include quaternary ammonium salt type diallylamine polymers obtained by polymerization of diallyldialkylammonium salts represented by formula (IIa).

[ chemical formula 3]

In the formula (IIa), R ⁷ And R ⁸ Each independently represents a hydrogen atom or a chain or cyclic hydrocarbon group which may have a substituent, and is 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, or may contain the nitrogen atom of the quaternary ammonium group as a ring-constituting atom. Further, as in the case of the repeating unit represented by the following formula (III), the two polymer chains may be crosslinked by a quaternary ammonium group.

[ chemical formula 4]

In said formula (III), X ⁴ ～X ⁷ Each independently a single bond or a divalent linking group.

Counter anions Z as quaternary ammonium salts ^- Examples thereof include: cl ^- 、Br ^- 、I ^- 、ClO ₄ ^- 、BF ₄ ^- 、CH ₃ COO ^- 、PF ₆ ^- 、HSO ₄ ^- 、C ₂ H ₅ SO ₄ ^- . At X ¹ ～X ⁷ In the case of a divalent linking group, as specific examples thereof, there can be cited: methylene, alkylene having 2 to 10 carbon atoms, arylene, -CONH-R-group, -COO-R-group (wherein, R represents a single bond, a methylene group, an alkylene group having 2 to 10 carbon atoms, an ether group (alkoxyalkyl) having 2 to 10 carbon atoms, or the like.

Examples of the polymer having an amino group in a side chain include a polymer having a repeating unit represented by the following formula (IV).

[ chemical formula 5]

In the formula (IV), R ¹¹ And R ¹² Each independently represents a hydrogen atom or a linear or cyclic hydrocarbon group which may have a substituent, R ¹¹ And R ¹² May be bonded to each other to form a ring structure. R ¹³ Is a hydrogen atom or a methyl group, X ¹¹ Is a single bond or a divalent linking group. The amino group may be any of a primary amino group, a secondary amino group, and a tertiary amino group, and may form an ammonium salt. As the counter anion of the ammonium salt, there may be mentioned the counter anion Z mentioned above as the quaternary ammonium salt ^- The anion is described.

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

[ chemical formula 6]

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 of 0 to 2. X ¹² And X ¹³ Each independently a single bond or a divalent linking group.As a specific example of the polymer having the repeating unit of formula (V), a diallylamine polymer obtained by polymerization of diallylamine or a diallylamine salt is cited.

X in the formulae (IV) and (V) ¹¹ ～X ¹³ In the case of a divalent linking group, as a specific example thereof, the foregoing is exemplified by X ¹ ～X ⁷ The groups recited in the specific examples of (a).

The polymer having an amino group or a quaternary ammonium group in a side chain may also be a copolymer. In the case where the polymer is a copolymer, the copolymer may contain "a repeating unit having an amino group or a quaternary ammonium group" and "a repeating unit not containing any of an amino group and a quaternary ammonium group". The arrangement of the repeating units in the copolymer is not particularly limited, and may be any of an alternating copolymer, a block copolymer, and a random copolymer. When the copolymer is a block copolymer or a random copolymer, the proportion 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, and still more preferably 40 mol% or more.

Examples of the "repeating unit not containing any of an amino group and a quaternary ammonium group" contained in the copolymer include structures derived from (meth) acrylic acid, an alkyl (meth) acrylate, an aminoalkyl (meth) acrylate, a styrene derivative, sulfur dioxide, and the like. The polymer having a structure derived from a quaternary ammonium salt type diallylamine represented by the general formula (II) and the polymer having a structure derived from a diallylamine represented by the general formula (IV) preferably have a sulfur dioxide-derived structural unit represented by the following formula as a repeating unit of a copolymer.

[ chemical formula 7]

The polymer may have an amino group and a quaternary ammonium group in a side chain. Further, two or more kinds of the polymers may be used simultaneously, and a polymer having an amino group in a side chain and a polymer having a quaternary ammonium group in a side chain may be used simultaneously.

The concentration of the polymer in the microetching solution is preferably 0.0005 to 2g/L, more preferably 0.005 to L g/L, still more preferably 0.008 to 0.5g/L, and particularly preferably 0.01 to 0.2g/L, in order to form a copper layer surface having excellent adhesion.

< other additives >

The microetching agent of the present invention can be prepared by dissolving the respective components in ion-exchanged water or the like. The microetching agent may contain components other than the above-described components. For example, a nonionic surfactant as an antifoaming agent or a complexing agent such as pyridine for improving the dissolution stability of copper may be added. Other various additives may be added as required. When these additives are added, the concentration of the additives in the microetching solution is preferably about 0.0001 to 20% by weight.

If the microetching agent contains hydrogen peroxide, the copper dissolves due to the oxidizing power of the hydrogen peroxide, and therefore, the formation of a roughened shape on a copper layer having large copper crystal grains and high crystal plane orientation uniformity, such as rolled copper, may be inhibited. In addition, the absence of hydrogen peroxide has the advantage of enabling simplified concentration management of the solution or waste liquid treatment. Therefore, the hydrogen peroxide concentration in the microetching agent is most preferably 0. On the other hand, the mixing of a trace amount of hydrogen peroxide contained in the raw material can be tolerated. The hydrogen peroxide concentration of the microetching agent is preferably 0.1 wt% or less, and more preferably 0.01 wt% or less.

[ use of microetching agent ]

The microetching agent can be widely used for roughening the surface of the copper layer. Fine irregularities are uniformly formed on the surface of the copper layer after the treatment, and the copper layer has good adhesion to resins such as a prepreg, a plating resist, a solder resist, a plating resist, and a cover lay. Further, the surface of the copper layer after the treatment is excellent in solderability, and therefore, is particularly useful for manufacturing various wiring boards including those for Pin Grid Array (PGA) and Ball Grid Array (BGA). Further, the present invention is also useful in surface treatment of lead frames.

The microetching agent of the present invention has a small difference in roughened shape due to a difference in crystallinity of copper, and can form a roughened shape having excellent adhesion to a resin or the like for both electrolytic copper and rolled copper. Therefore, even when the copper foil to be processed is different, the same etchant can be used repeatedly without replacing the etchant.

[ method for manufacturing Wiring Board ]

In the production of the wiring board, the surface of the copper layer is roughened by bringing the surface of the copper layer into contact with the microetching agent. In the case of manufacturing a wiring board including a plurality of copper layers, only one of the plurality of copper layers may be treated with the microetching solution, or two or more copper layers may be treated with the microetching solution. The microetching agent of the prior art is mainly used for surface roughening of the electrolytic copper foil, and on the contrary, the microetching agent can form a uniform roughened shape on the surface for either of the electrolytic copper and the rolled copper. Therefore, the microetching solution of the present invention is also suitable for roughening of a copper layer made of rolled copper on the surface of a surface to be treated (a surface in contact with the microetching solution).

In the roughening treatment, a method of bringing the surface of the copper layer into contact with the microetching agent is not particularly limited, and examples thereof include a method of spraying the microetching agent onto the surface of the copper layer to be treated, a method of immersing the copper layer to be treated in the microetching agent, and the like. When spraying, it is preferable to perform etching under conditions of a microetching agent temperature of 10 to 40 ℃, a spraying pressure of 0.03 to 0.3MPa, and a spraying time of 5 to 120 seconds. In the case of immersion, the etching is preferably performed under conditions where the temperature of the microetching agent is 10 to 40 ℃ for 5 to 120 seconds. In the case of immersion, it is preferable to blow air into the microetching agent by bubbling (bubbling) or the like in order to oxidize copper (I) ions generated in the microetching agent by etching copper into copper (II) ions. When the microetching agent does not substantially contain hydrogen peroxide, it is easy to treat the waste liquid after use, and for example, it can be treated by a conventional and simple method using neutralization or a polymer flocculant.

The etching amount in the roughening treatment is not particularly limited, and is preferably 0.05 μm or more, more preferably 0.1 μm or more, in terms of forming a uniform uneven shape regardless of the crystallinity of copper. If the etching amount is too large, there may be problems such as disconnection due to complete etching of the copper layer, or increase in resistance due to reduction in the cross-sectional area of the wiring. Therefore, the etching amount is preferably 5 μm or less, more preferably 3 μm or less. The "etching amount" means an average etching amount (dissolved amount) in the depth direction, and can be calculated from the weight and specific gravity of copper dissolved by the microetching agent and the front projection area of the copper surface.

After the roughening treatment step, the roughened copper layer surface is preferably cleaned with an acidic aqueous solution in order to remove the generated stain. As the acidic aqueous solution used for the cleaning, hydrochloric acid, an aqueous sulfuric acid solution, an aqueous nitric acid solution, and the like can be used. Hydrochloric acid is preferable in terms of its small influence on the roughened shape and high stain removability. The acid concentration of the acidic aqueous solution is preferably 0.3 to 35% by weight, more preferably 1 to 10% by weight, in terms of stain-removing property. The cleaning method is not particularly limited, and examples thereof include: a method of spraying an acidic aqueous solution on the roughened copper layer surface, a method of immersing the roughened copper layer in an acidic aqueous solution, or the like. When spraying, it is preferable to wash the surface of the substrate at an acidic aqueous solution temperature of 15 to 35 ℃ and a spraying pressure of 0.03 to 0.3MPa for 3 to 30 seconds. In the case of immersion, it is preferable to wash the substrate at an acidic aqueous solution temperature of 15 to 35 ℃ for 3 to 30 seconds.

When the microetching agent is continuously used, it is preferable to perform the roughening treatment while adding the replenishment liquid. By performing the roughening treatment while adding the replenishment liquid, the concentration of each component in the microetching agent during the treatment can be appropriately maintained. The make-up solution is an aqueous solution comprising a mineral acid, a source of copper (II) ions, a source of halide ions and the polymer. The amount of the replenishment liquid to be added or the timing of addition of the replenishment liquid may be appropriately set in accordance with the concentration control range of each component. The components in the replenishment liquid are the same as those contained in the microetching solution. The concentration of each component in the replenishment liquid may be appropriately adjusted depending on the initial concentration of the microetching agent used for the treatment.

After the treatment with the microetching agent, the resin may be treated with an aqueous or alcoholic azole solution in order to further improve the adhesion to the resin. Further, after the treatment with the microetching agent, an oxidation treatment called a brown oxide treatment or a black oxide treatment may be performed.

[ examples ]

Next, examples of the present invention will be described together with comparative examples. Furthermore, the present invention is not to be construed as being limited by the following examples.

< treatment with microetching solution >

A base material having a rolled copper foil (HA foil, manufactured by JX metal) was prepared as a test substrate. For each of these substrates, each microetching agent (30 ℃) shown in table 1 was used, and sprayed onto the copper foil of the test substrate under a spray pressure of 0.1MPa, and etching was performed with the etching time adjusted so that the etching amount of copper was 1.0 μm. Then, the etched surface was washed with water, immersed in hydrochloric acid (hydrogen chloride concentration: 3.5 wt%) at 25 ℃ for 15 seconds, washed with water, and dried.

As the test substrate, the following substrates were used: a substrate obtained by copper plating 18 μm thick on a glass cloth epoxy resin-impregnated copper-clad laminate (product name: MCL-E-67, 10 cm. Times.10 cm, thickness 0.2mm, manufactured by Hitachi chemical Co., ltd.) having electrolytic copper foils of 35 μm thick attached to both surfaces of an insulating base material was subjected to etching, acid cleaning, water cleaning and drying in the same manner as described above using the etching agents of examples 1 to 8 and comparative examples 1 to 2, 5 and 8 to 9.

The details of the polymers a to D shown in tables 1 and 2 are as follows. These polymers were used in such a manner that the concentration of the polymers in the etchant was the blending amount shown in table 1. The balance of the composition of each etchant shown in tables 1 and 2 was ion-exchanged water.

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

[ chemical formula 8]

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

[ chemical formula 9]

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

[ chemical formula 10]

Polymer D: random copolymer of vinylpyrrolidone-N, N-dimethylaminoethylmethacrylamide diethyl sulfate having the following structure (weight average molecular weight: about 80 ten thousand)

[ chemical formula 11]

< evaluation of uniformity of roughening by observation with a scanning electron microscope >

The surface of the copper layer of the treated test substrate was observed with a Scanning Electron Microscope (SEM) (model JSM-7000F, manufactured by japan electronics). SEM observation images are shown in fig. 1 to 25. The SEM observation images of each example, comparative example, and the corresponding are shown in tables 1 and 2. The scores of the roughened shapes of the rolled copper surfaces obtained based on the following criteria are shown in tables 1 and 2.

< evaluation criteria >

1: the surface is not uneven

2: the surface is formed with concave-convex but not roughened

3: the surface is roughened with irregularities, but the irregularities are large and the roughening is uneven

4: forming fine irregularities on the entire surface

5: fine unevenness is formed on the entire surface and in-plane uniformity is high

TABLE 1

/>

From this, it is understood that when the roughening treatment was performed using the microetching agent of examples 1 to 14, a uniform roughened shape was formed on the surface of both of the rolled copper and the electrolytic copper. In particular, for rolled copper, as shown in table 1, it is understood that the evaluation score is also high as a whole.

TABLE 2

From this, on the other hand, since the microetching agent of comparative example 1 has (Cs/Ch) =0.0042, the roughened shape is not good when used for the roughening treatment. It is also clear that the microetching agents of comparative examples 2 to 5 have large (Cs/Ch) and therefore, when used for roughening treatment, the roughened shape is not good.

It is also clear that the microetching agents of comparative examples 6 to 7 and 9 do not have a halide ion source, and therefore, when used for roughening treatment, the roughened shape is not good.

Further, it is understood that since the microetching agent of comparative example 8 uses an organic acid instead of an inorganic acid, the roughened shape is not good when used for the roughening treatment.

Claims

1. A microetching agent for copper, which is used for roughening the surface of copper,

characterized in that it is an acidic aqueous solution containing an inorganic acid, a copper (II) ion source, a halide ion source and a polymer, and

the polymer is a water-soluble polymer with a side chain containing amino or quaternary ammonium group and a weight average molecular weight of more than 1000,

as the inorganic acid, a sulfate ion source may be contained,

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 3.875 times or less than the molar concentration of the copper (II) ion source, and

the concentration of halide ions in the microetching solution is 0.5 to 3 (mol/L).

2. The microetching agent according to claim 1, wherein the molar concentration of the copper (II) ion source is 0.01 to 2 (mol/L).

3. The microetching agent according to claim 1, wherein the halide ion source has a molar concentration of 0.05 to 5 (mol/L).

4. The microetching agent according to claim 2, wherein the halide ion source has a molar concentration of 0.05 to 5 (mol/L).

5. The microetching agent according to any one of claims 1 to 4, wherein the polymer has a concentration by weight of 0.0005 to 2 (g/L).

6. A method for manufacturing a wiring board including a copper layer,

characterized in that it comprises a roughening treatment step of bringing the surface of a copper layer into contact with the microetching agent according to any one of claims 1 to 5 to roughen the surface of the copper layer.

7. The method of manufacturing a wiring board according to claim 6, wherein a surface of the copper layer on a surface in contact with the microetching agent is formed of rolled copper.

8. The method for manufacturing a wiring substrate according to claim 6 or 7, wherein in the roughening treatment step, a replenishment solution comprising an acidic aqueous solution containing an inorganic acid, a halide ion source and a polymer is added to the microetching agent

The polymer in the replenishment solution is a water-soluble polymer having a weight-average molecular weight of 1000 or more and containing an amino group or a quaternary ammonium group in a side chain.