TW201912839A - Microetching agent and method of manufacturing wiring board - Google Patents

Abstract

This microetching agent contains an inorganic acid, cupric ions, halide ions, and a water-soluble cationic polymer which contains a quaternary ammonium group in a side chain, while having a weight average molecular weight of 1,000 or more. The molar concentration of the halide ions is 5 to 100 times the molar concentration of the cupric ions in this microetching agent. It is preferable that the pH of this microetching agent is 2 or less. By using this microetching agent, a copper surface is able to be provided with a roughened shape that exhibits excellent adhesion to a resin and the like even if the amount of etching is low.

Description

   Micro-etching agent and manufacturing method of wiring board   

The invention relates to a copper micro-etching agent and a method for manufacturing a wiring board.

When manufacturing a printed wiring board, in order to improve the adhesion between the copper surface and resin materials such as solder resist, the copper surface is roughened with a micro-etching agent (roughening agent). As the micro-etching agent for copper or copper alloy, organic acid-based micro-etching agents (for example, Patent Document 1) and inorganic acid-based micro-etching agents (for example, Patent Document 2) are known. These micro-etching agents include an acid and an oxidizing agent, and in addition, halogens, polymers, ammonium salts, amines, surfactants, and the like are added to adjust the roughening shape, etching rate, and the like.

[Prior Technical Literature]

[Patent Literature]

Patent Document 1: WO2014 / 017115.

Patent Document 2: WO2007 / 024312.

[Technical solutions]

In the roughening using a micro-etching agent, the larger the etching amount, the more roughening is performed, and therefore, there is a tendency for the adhesion to the resin and the like to be improved. On the other hand, if the copper wiring is roughened with a micro-etching agent, the line may become thinner as the etching progresses, and defects such as increased resistance or disconnection may occur. Along with the narrowing of the wiring (fine wiring), the influence of the thinning of the wiring becomes significant, so a micro-etching agent capable of achieving high adhesion with a low etching amount is required.

The organic acid-based micro-etching agent of Patent Document 1 can form a roughened shape excellent in adhesion with a solder resist or the like on the copper surface even if the etching amount is 1 μm or less. However, since the organic acid-based micro-etching agent contains organic acid, ammonium salt, etc. in a high concentration, dedicated drainage and waste liquid treatment equipment is required, which is hardly versatile.

Patent Document 2 describes that a hydrochloric acid-based micro-etching agent containing polyethylenimine can form a roughened shape excellent in adhesion with a solder resist or the like on a copper surface at an etching amount of about 1.5 μm. Compared with organic acid-based etchant, inorganic acid-based etchant has the advantage of easy drainage and waste liquid treatment. However, in order to use an inorganic acid-based etchant to ensure adhesion to the resin, it is necessary to increase the amount of etching compared to the case of using an organic acid-based etchant.

In view of the above circumstances, an object of the present invention is to provide an inorganic acid-based micro-etching agent that can form a roughened shape with excellent adhesion to resin or the like on a copper surface even at a low etching amount.

The invention relates to a copper micro-etching agent, which is used for copper surface roughening. In addition, "copper" in this specification includes copper and copper alloy. In addition, "copper layer" also includes a copper wiring pattern layer. The micro-etching agent of the present invention is an inorganic acid-based micro-etching agent containing inorganic acid, copper ion, halide ion and cationic polymer. The cationic polymer is a water-soluble polymer containing a quaternary ammonium group in the side chain and having a weight average molecular weight of 1,000 or more. The molar concentration of the halide ion in the micro-etching agent is 5 to 100 times that of the copper ion. The pH of the micro-etching agent is preferably 2 or less. The weight concentration of copper ions is preferably 50 times to 2000 times the weight concentration of the polymer.

Furthermore, the present invention relates to a method of manufacturing a wiring board, which manufactures a wiring board including a copper layer. The method of manufacturing a wiring board includes a step of roughening the micro-etching agent by contacting the copper surface (roughening treatment step). In the roughening treatment step, in order to maintain the composition of the micro-etching agent within a predetermined range, a replenishing solution may be added to the micro-etching agent. The etching amount in the roughening treatment is, for example, 1 μm or less. In addition, the "etching amount" refers to the average etching amount (dissolving amount) in the depth direction, and is calculated based on the weight and specific gravity of copper dissolved by the micro-etching agent and the front projection area of the copper surface. The following "etching amount" is also the same.

According to the present invention, even with a low etching amount, a roughened shape excellent in adhesion with resin or the like can be formed on the copper surface.

Fig. 1 is a scanning electron microscope photograph of the copper surface treated by the solution of preparation 1.

Fig. 2 is a scanning electron microscope photograph of the copper surface treated with the solution of preparation 2.

Fig. 3 is a scanning electron microscope photograph of the copper surface treated by the preparation of the solution of 3.

Fig. 4 is a scanning electron microscope photograph of the copper surface treated by the preparation of the solution of 8.

Fig. 5 is a scanning electron microscope photograph of the copper surface treated by the preparation of the solution of 9.

Fig. 6 is a scanning electron microscope photograph of the copper surface treated by the preparation of 10 solutions.

Fig. 7 is a scanning electron microscope photograph of the copper surface treated by the preparation of the solution of 11.

Fig. 8 is a scanning electron microscope photograph of the copper surface treated by the preparation of the solution of 12.

Fig. 9 is a scanning electron microscope photograph of the copper surface treated by the preparation of the 13 solution.

FIG. 10 is a scanning electron microscope photograph of the copper surface treated by the preparation of the 18 solution.

FIG. 11 is a scanning electron microscope photograph of the copper surface treated with the solution of 19.

FIG. 12 is a scanning electron microscope photograph of the copper surface treated by the preparation of the 20 solution.

Fig. 13 is a scanning electron microscope photograph of the copper surface treated by the preparation of the solution of 21.

Fig. 14 is a scanning electron microscope photograph of the copper surface treated by the preparation of the 22 solution.

Fig. 15 is a scanning electron microscope photograph of the copper surface treated with the solution of 23.

Fig. 16 is a scanning electron microscope photograph of the copper surface treated by the preparation of the 24 solution.

Fig. 17 is a scanning electron microscope photograph of the copper surface treated by the preparation of the 25 solution.

Fig. 18 is a scanning electron microscope photograph of the copper surface treated by the preparation of the 26 solution.

FIG. 19 is a scanning electron microscope photograph of the copper surface treated by the preparation of 27 solution.

FIG. 20 is a photograph of the surface of the test piece of the evaluation result A in the solder heat resistance test.

FIG. 21 is a photograph of the surface of the test piece of the evaluation result B in the solder heat resistance test.

FIG. 22 is a photograph of the surface of the test piece of the evaluation result X in the solder heat resistance test.

[Composition of Micro Etching Agent]

The micro-etching agent of the present invention is used for roughening the surface of copper. The micro-etching agent is an acidic aqueous solution containing inorganic acids, copper ions, halide ions, and polymers. Hereinafter, each component contained in the micro-etching agent of the present invention will be described.

<Copper ion>

The copper ion system acts as an oxidizing agent for oxidizing copper. Examples of the copper ion source prepared in the micro-etching agent include: copper halide such as copper chloride and copper bromide; inorganic acid salts such as copper sulfate and copper nitrate; organic acid salts such as copper formate and copper acetate; copper hydroxide; Copper oxide, etc. Copper halide generates copper ions and halide ions in an aqueous solution, so it can be used as a substance having both the halide ion source and the copper ion source. As the copper ion source, copper halide, copper oxide, or inorganic acid salt is preferred. In addition, the composition in the case where copper oxide and a halogenated hydrogen acid such as hydrochloric acid coexist is the same as the case in which copper halide is dissolved. The copper oxide is preferably a copper oxide that dissolves quickly and easily in an acid, and is more preferably a soluble copper oxide used in "a copper plating solution using an insoluble anode".

The copper ion concentration of the micro-etching agent is preferably 0.0005 moles / L to 0.5 moles / L, more preferably 0.001 moles / L to 0.3 moles / L, and further preferably 0.005 moles / L to 0.2 moles / L below. By adjusting the copper ion concentration, the etching rate becomes an appropriate range, so it is easy to control the etching amount.

<Inorganic acid>

The acid has a function of dissolving copper oxidized by copper ions in an aqueous solution, and also has a function of adjusting pH. The pH of the microetching agent is preferably 2 or less, more preferably 1.5 or less, and still more preferably 1 or less. That is, when it is convenient to increase the concentration of copper ions in the solution as the etching progresses, if the pH is within the above range, precipitation of copper hydroxide or the like can also be suppressed. Therefore, the stability of the solution is high, and a roughened shape with excellent adhesion to resin or the like can be formed on the copper surface.

From the viewpoint of keeping the pH of the micro-etching agent low, an inorganic acid is used as the acid. Compared with organic acids, inorganic acids are less likely to coordinate with copper ions in aqueous solutions. Therefore, by using an inorganic acid, it is possible to appropriately maintain the role of copper ions in the micro-etching agent as an oxidizing agent. The inorganic acid is preferably a strong acid such as halogenated hydrogen acid such as hydrochloric acid or hydrobromic acid, sulfuric acid or nitric acid. The hydrogen halide acid can be used as a substance having both the halide ion source and the acid. Therefore, the micro-etching agent of the present invention preferably contains a halogenated hydrogen acid as an inorganic acid. Among the halogenated hydrogen acids, hydrochloric acid (hydrogen chloride aqueous solution) is preferred. Two or more acids can be used in combination, and a small amount of organic acids can be used in addition to inorganic acids. The acid concentration of the micro-etching agent is preferably adjusted so that the pH falls within the above range.

<Halide ion>

The halide ion has the function of assisting the dissolution of copper and forming the surface of the copper layer with excellent adhesion. Examples of the halide ion include chloride ion and bromide ion. Among them, from the viewpoint of uniformly forming a roughened shape excellent in adhesion, chloride ion is preferable. The microetching agent may contain two or more kinds of halide ions.

Examples of the halide ion source prepared in the micro-etching agent include hydrogen halide acids such as hydrochloric acid and hydrobromic acid; sodium chloride, calcium chloride, potassium chloride, ammonium chloride, potassium bromide, sodium bromide, Copper chloride, copper bromide, zinc chloride, ferric chloride, tin bromide and other metal salts. Two or more halide ion sources can be used in combination. As described above, the hydrogen halide acid has the functions of both the halide ion source and the acid, and the copper halide has the functions of both the halide ion source and the copper ion source.

From the viewpoint of promoting the formation of a roughened shape on the copper surface, the concentration of halide ions in the micro-etching agent is preferably 0.005 mol / L to 10 mol / L, more preferably 0.05 mol / L to 5 mol Ear / L, and further preferably 0.1 mole / L to 3 mole / L. By setting the halide ion concentration to the above range, there is a tendency to promote the dissolution of cuprous ions generated by the oxidation of copper in the solution and to suppress the generation of contaminants on the surface of the copper layer. Furthermore, as described below, the micro-etching agent contains an excess of halide ions relative to copper ions. Therefore, the appropriate range of the halide ion concentration is set according to the copper ion concentration.

<Polymer>

The micro-etching agent of the present invention contains a water-soluble polymer having a quaternary ammonium group on the side chain and a weight average molecular weight of 1,000 or more. Together with the halide ion, the polymer has the effect of forming a roughened shape with excellent adhesion. In the micro-etching agent, copper ions and halide ions coexist with a polymer having a quaternary ammonium group on the side chain, whereby fine irregularities can be uniformly formed on the surface of copper. From the viewpoint of forming a uniform roughened shape, the weight average molecular weight of the polymer is preferably 2,000 or more, and more preferably 3,000 or more. From the viewpoint of water solubility, the weight average molecular weight of the polymer is preferably 5 million or less, and more preferably 2 million or less. The weight average molecular weight is a value obtained by gel permeation chromatography (GPC; gel permeation chromatography) analysis and conversion using polyethylene glycol.

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

In formula (I), R ¹ to R ³ are each independently a chain or cyclic hydrocarbon group which 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 Z ^- 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 (meth) acrylate aminoalkyl ester polymer, and the like.

The polymer having a quaternary ammonium group in the side chain may also be a polymer having 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 as shown in the following formula (II).

In the above formula (II), R ⁵ and R ⁶ are chain or cyclic hydrocarbon groups 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 having a repeating unit of formula (II), a quaternary ammonium salt type diallyl obtained by polymerization of diallyl dialkyl ammonium salt represented by formula (IIa) can be cited Amine polymer.

In the above 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 also have a double bond between the nitrogen atom and the carbon atom. Quaternary ammonium salts as the counter anion Z ^{-, include: Cl -, Br -, I} -, ClO 4 -, BF 4 -, CH 3 COO -, PF 6 -, HSO 4 -, C 2 H 5 SO 4 ^- . When X ¹ to X ⁷ are divalent linking groups, specific examples of the divalent linking group include methylene groups, alkylene groups having 2 to 10 carbon atoms, aryl groups, and -CONH-R -Group, -COO-R- group (wherein R is a single bond, methylene group, alkylene group having 2 to 10 carbon atoms, or ether group (alkoxyalkyl group) having 2 to 10 carbon atoms), etc.

The polymer containing a quaternary ammonium group on the side chain may also be a copolymer. When the polymer is a copolymer, the copolymer may also include a repeating unit containing a quaternary ammonium group and a repeating unit not containing a quaternary ammonium group. The arrangement of the repeating units in the copolymer is not particularly limited, and may be any of alternating copolymers, block copolymers, and random copolymers. When the copolymer is a block copolymer or a random copolymer, the ratio of the repeating unit containing quaternary ammonium groups to the monomer unit of the entire polymer is preferably 20 mole% or more, more preferably 30 mole Ear% or more, and more preferably 40 mole% or more. Examples of the repeating unit not containing a quaternary ammonium group include (meth) acrylic acid, alkyl (meth) acrylate, aminoalkyl (meth) acrylate, (meth) acrylamide, and benzene. Structures of ethylene derivatives, sulfur dioxide, etc.

In the above Patent Document 2, low molecular weight polyethylenimine is used as the polymer of the inorganic acid-based micro-etching agent, but even if a low molecular weight polyethylenimine having a molecular weight of less than 1,000 is used, it cannot The amount forms a fine roughened shape. The aforementioned Patent Document 1 describes an example of using a high molecular weight polyethylenimine as a polymer of an organic acid-based micro-etching agent. The micro-etching agent of the present invention mainly uses an inorganic acid as an acid, so the pH is low. Polyethylenimine having a cationic group in the main chain is unstable under strong acidity, and it is difficult to form a fine roughened shape. In contrast, cationic polymers containing quaternary ammonium groups in the side chain are also stable under strong acidity below pH 1 and contribute to the formation of fine roughened shapes.

From the viewpoint of forming the surface of the copper layer excellent in adhesion, the concentration of the polymer in the micro-etching agent is preferably 0.0002 g / L to 0.2 g / L, more preferably 0.001 g / L to 0.04 g / L, and It is preferably 0.004 g / L to 0.02 g / L. In addition, as described below, the appropriate range of the polymer concentration in the micro-etching agent is set according to the copper ion concentration.

<Ratio of each component>

One of the characteristics of the micro-etching agent of the present invention is that it contains an excessive amount of halide ions relative to copper ions. The halide ion concentration (molar concentration) of the micro-etching agent is preferably 5 times or more of the copper ion concentration, more preferably 7 times or more, and still more preferably 10 times or more. Since the micro-etching agent contains an excessive amount of halide ions relative to copper ions, even at a low etching amount, it is possible to form a roughened shape with excellent adhesion to resin or the like on the copper surface. From the viewpoint of forming a uniform roughened shape, the halide ion concentration is preferably 100 times or less the copper ion concentration, more preferably 70 times or less, and still more preferably 50 times or less.

In an etchant containing halide ions and copper ions as an oxidant, metallic copper is oxidized and copper ions are reduced, thereby generating cuprous ions. Since the solubility of cuprous halide such as copper chloride (I) is small, insoluble contaminants are deposited on the copper surface. On the other hand, since one cuprous ion and four halide ions form a soluble complex, if there is an excessive amount of halogen, the cuprous halide quickly re-dissolves. That is, in the presence of excessive halogen, it is possible to suppress the accumulation of contaminants on the copper surface, so that each component constituting the micro-etching agent can easily contact the metal copper surface. It is considered that in such an environment, the effect of the above-mentioned cationic polymer is easily exhibited, and even with a low etching amount, it is easy to form fine irregularities excellent in adhesion with the resin.

From the viewpoint of improving the surface shape formation effect using the cationic polymer, the weight concentration of copper ions in the etchant is preferably 50 times to 2000 times the weight concentration of the cationic polymer, more preferably 100 times to 1500 Times, and more preferably 200 times to 1000 times.

<Other additives>

The micro-etching agent of the present invention can be prepared by dissolving the aforementioned components in ion-exchanged water or the like. The microetching agent may contain components other than the above. For example, for the purpose of homogenization of roughening, a nonionic surfactant may also be added. Nonionic surfactants also function as defoamers. In addition, various additives may be added as needed. When using these additives, the concentration of the additives in the microetching agent is preferably about 0.0001% by weight to 20% by weight.

[Use of micro-etching agent]

The above micro-etchants can be widely used for roughening the surface of the copper layer. It forms fine irregularities uniformly on the surface of the treated copper, and has good adhesion to resins such as prepreg, anti-plating layer, anti-etching layer, solder resist, anti-electrodeposition layer, and covering layer. In addition, since the roughened copper surface is also excellent in solderability, it is particularly useful when manufacturing various wiring substrates including a pin grid array (PGA) or ball grid array (BGA). Furthermore, it is also useful for the surface treatment of a lead frame.

In particular, the micro-etching agent of the present invention can form a surface with excellent adhesion at a low etching amount, so for printed wiring boards requiring fine copper wiring, fan-out wafer level packages (FOWLP; Fan-out wafer level package) 1. The large-scale integrated circuit (LSI; large scale integration) rewiring copper layer, etc., is useful for improving the adhesion, and helps to suppress the high resistance or disconnection of copper wiring.

[Manufacturing method of wiring board]

When manufacturing a wiring board, the copper surface is roughened by contacting the above-mentioned micro-etching agent with the copper surface. In the case of manufacturing a wiring board including multiple copper layers, only one of the plurality of copper layers may be processed using the above-mentioned micro-etching agent, or two or more copper layers may be processed using the above-mentioned micro-etching agent.

In the roughening process, the method of contacting the micro-etching agent with the copper surface is not particularly limited. For example, a method of spraying the micro-etching agent on the surface of the copper layer to be treated, or immersing the copper layer to be treated by micro-etching The method in the agent. In the case of spraying, it is preferable to perform etching under the conditions of a microetching agent temperature of 10 ° C. to 40 ° C., a spray pressure of 0.03 MPa to 0.3 MPa, and 5 seconds to 120 seconds. In the case of performing the immersion, it is preferable to perform the etching under the conditions of the micro-etching agent at a temperature of 10 ° C. to 40 ° C. for 5 seconds to 120 seconds. In addition, in the case of immersion, in order to oxidize the cuprous ions generated in the micro-etching agent by copper etching to copper ions, it is preferable to add the micro-etching agent by bubbling etc. Blow in the air. The waste liquid after the use of the micro-etching agent of the present invention is easy to handle, for example, it can be processed by a simple method such as neutralization with an alkali and a polymer coagulant.

The L ^* value of the copper surface after roughening treatment with a micro etchant is preferably 70 or less, and more preferably 65 or less. The L ^* value is the brightness L ^* in the L ^* a ^* b ^* color space (JIS Z 8781-4), which is measured by the method described in the examples described later. The untreated copper foil has metallic luster and L ^* is about 80 to 90. Regarding the roughened copper foil, the incident light diffusely reflects in multiple directions, and the reflection is repeated to attenuate. Therefore, if the copper foil is roughened to form a fine uneven shape, the L ^* value tends to become smaller.

The L ^* value of the copper surface can be controlled within the above range by adjusting the preparation ratio or etching amount of the micro-etching agent. In one embodiment of the present invention, the blending ratio or etching amount (etching time) of the micro-etching agent may be adjusted so that the L ^* value on the surface of the copper layer falls within the above range. For example, after roughening the surface of the copper layer with a micro-etching agent, the L ^* value of the surface of the copper layer after roughening can be monitored while controlling the amount of replenishment solution or the time point of replenishment solution to be described later .

The amount of etching in the roughening treatment is not particularly limited. From the viewpoint of improving the adhesion with the resin, the etching amount is preferably 0.05 μm or more, and more preferably 0.1 μm or more. In the pretreatment of the solder resist coating step of the printed wiring board that requires fine wiring, if the etching amount is too large, it may cause disconnection due to the complete etching of the copper layer, or due to the reduction in the cross-sectional area of the wiring Bad conditions such as increased resistance. Therefore, the etching amount is preferably 1 μm or less, more preferably 0.7 μm or less, and still more preferably 0.5 μm or less.

In the case where the micro-etching agent is continuously used, the roughening treatment may be performed while adding the replenishing liquid. By performing the roughening treatment while adding the replenishing liquid, the concentration of each component in the micro-etching agent during the treatment can be maintained to be appropriate. The replenishing liquid is preferably an aqueous solution containing components (acid, halide ion, and the aforementioned polymer) that decrease with the progress of etching. A copper ion source such as copper oxide may also be included in the replenisher. The addition amount of the replenishing liquid or the time point of the replenishing liquid can be appropriately set according to the concentration management range of each component. Each component in the replenishing solution is the same as the component contained in the above-mentioned micro-etching agent. The concentration of each component in the replenishing solution can be appropriately adjusted according to the initial concentration of the microetching agent used for the treatment and the like. The composition of the replenishing solution may be the same as the bath solution (micro-etching solution before use).

After the roughening treatment step, the roughened surface can also be washed with an acidic aqueous solution. As the acidic aqueous solution for washing, hydrochloric acid, sulfuric acid aqueous solution, nitric acid aqueous solution, etc. can be used. In terms of less influence on the roughened shape and high detergency, hydrochloric acid is preferred. The acid concentration of the acidic aqueous solution is preferably 0.3% by weight to 35% by weight, and more preferably 1% by weight to 10% by weight. The cleaning method is not particularly limited, and examples include a method of spraying an acidic aqueous solution on the surface of the roughened copper layer, or a method of immersing the roughened copper layer in the acidic aqueous solution.

After the treatment with the micro-etching agent, in order to further improve the adhesion with the resin, it can also be treated with an azole aqueous solution or an alcohol solution. In addition, after treatment with a micro-etching agent, oxidation treatment such as brown oxide treatment or black oxide treatment may also be performed.

[Example]

Next, an embodiment of the present invention will be described. Furthermore, the present invention is not limited to the following examples and explained.

[Preparation of Micro Etching Agent]

According to the formulation shown in Table 1-1 to Table 1-2, a solution (microetching agent) was prepared. The details of Polymer A to Polymer I are as follows. These polymers are used in such a way that the concentration in the solution becomes the formulated amount shown in the table.

Polymer A: Vinylpyrrolidone-N, N-dimethylaminoethylmethacrylamide diethyl sulfate random copolymer (weight average molecular weight about 800,000) having the following structure.

Polymer B: a diallyldimethylammonium hydrochloride-sulfur dioxide alternating copolymer having the following repeating units (weight average molecular weight about 5000).

Polymer C: Acrylamide-dimethylaminoethyl acrylate methyl chloride quaternary salt copolymer (weight average molecular weight about 2 million).

Polymer D: dimethyl quaternary methacrylate sulfate dimethyl quaternary salt polymer (weight average molecular weight about 300,000).

Polymer E: polymer of diallyl dimethyl ammonium chloride (weight average molecular weight about 300,000).

Polymer F: poly (oxyethyleneoxypropylene (5E.O., 5P.O.)) glycol monoether (number average molecular weight about 510).

Polymer G: Polyethylenimine (weight average molecular weight about 70,000).

Polymer H: Polyethylenimine (weight average molecular weight about 300).

Polymer I: polyoxyethylene-polyoxypropylene block polymer adduct of ethylenediamine represented by the following formula.

The remaining part of the formulated ingredients in the table is ion-exchanged water. In formulation 26, formic acid (pKa = 3.75) was added as organic acid in formulation 2, and the volume was adjusted to 1 L with ion-exchanged water, and 48% sodium hydroxide aqueous solution was added dropwise to adjust to pH 3.75 (same as pKa of organic acid PH). In the preparation 27, acetic acid (pKa = 4.76) was added to the preparation 2 as an organic acid, and the volume was adjusted to 1 L with ion-exchanged water, and a 48% sodium hydroxide aqueous solution was added dropwise to adjust to pH 4.76. These solutions contain hydrochloric acid as an inorganic acid, but since they are adjusted to a pH region where the organic acid salt exhibits buffer energy, they have substantially the same composition as the organic acid-based etchant. In addition, the pH of the solutions of the formulation 1 to the formulation 25 using only inorganic acids are all 1.0 or less.

[Treatment of copper using micro-etching agent]

Prepare a test board consisting of a copper clad laminate impregnated with glass cloth epoxy resin impregnated with 35 μm thick copper foil on both sides of an insulating substrate (manufactured by Hitachi Chemical Co., Ltd., product name: MCL-E -67, 10cm × 10cm, thickness 0.2mm), 18μm copper plating. Next, each micro-etching agent (30 ° C) shown in Table 1-1 to Table 1-5 was sprayed onto the surface of the copper plating layer of the above test substrate under a spray pressure of 0.10 MPa to become 0.5 μm. The etching amount is adjusted by adjusting the etching time. Then, it was washed with water, and the etching surface was immersed in hydrochloric acid (hydrogen chloride concentration: 3.5% by weight) at a temperature of 30 ° C. for 10 seconds, then washed with water and dried.

Using a scanning electron microscope (SEM; scanning electron microscopy) (model JSM-7000F, manufactured by JEOL Ltd.), the surface of the copper layer of the test substrate after the treatment was observed. The SEM observation images are shown in FIGS. 1 to 19. The correspondence between the preparation of each solution and the SEM observation image is shown in Table 1-1 and Table 1-2.

<Adhesion Evaluation by Solder Heat Resistance Test>

A prepreg impregnated with glass cloth epoxy resin (manufactured by Hitachi Chemical Co., Ltd.) was laminated on the etched surface of the test substrate after drying by lamination (pressing pressure: 30 MPa, temperature: 170 ° C., time: 60 minutes). , Product name: GEA-67N, thickness 0.1mm). Then, the peripheral part of the laminated substrate was cut out to prepare a test piece. The test piece was left in an environment of 120 ° C (relative humidity: 100%) for 2 hours, and then immersed in a molten solder bath at 230 ° C for 30 seconds. Visually observe each test piece after immersion, and evaluate the test piece with no bulging at all as A (refer to FIG. 20), and the area with bulging within 10% of the surface is evaluated as B (refer to FIG. 21) The test piece that swelled out over 10% of the surface was evaluated as X (see FIG. 22). The results are shown in Table 1-1 and Table 1-2. In addition, if the adhesion between the copper foil and the resin is good, no bulging is observed.

<Roughened surface evaluation based on L ^* value>

For the etched surface of the test substrate after drying, arbitrarily select 3 locations, and measure the L ^* value using a color difference meter (model: CR-10) manufactured by Konica Minolta, and calculate the L ^* value average value. The results are shown in Table 1-1 and Table 1-2.

According to the results in Table 1-1 and Table 1-2, there is a correlation between the L ^* value of the roughened copper surface and the solder heat resistance test result. The smaller the L ^* value, the better the solder heat resistance and the copper The better the adhesion between the surface and the resin.

In the formulations 1 to 3 using the polymer A, the L ^* value of the copper surface after roughening was 55 or less, and a roughened shape excellent in adhesion with the resin was formed (see FIGS. 1 to 3). In the formulations 1 to 3, the concentration difference of each component is large. However, since the molar concentration ratio of halogen to copper ions and the weight concentration ratio of copper ions to polymers are within a predetermined range, it can be considered that the same roughened shape is formed.

In Blend 4 to Blend 7, the L ^* value of the roughened copper surface is 65 or less. On the other hand, in the formulations 13 to 17 (see FIG. 9), the L ^* value of the roughened copper surface is larger than the formulations 1 to 11 and the formation of the roughened shape is insufficient.

From these results, it can be seen that by adjusting the compounding ratio of the halide ion, the copper ion, and the polymer, even at a low etching amount of about 0.5 μm, a roughened shape excellent in adhesiveness with the resin can be formed.

In the formulations 8 to 11 (refer to FIGS. 4 to 7) including the polymer B to the polymer E instead of the polymer A, the L ^* value of the roughened copper surface is 65 as well as the formulation 1 to the formulation 7 the following. On the other hand, in the formulation 12 (refer to FIG. 8) of the un-formulated polymer and the formulation 20 and formulation 21 (refer to FIGS. 12 and 13) including the polymer G (high molecular weight polyethylenimine), the surface was Roughening, but the L ^* value of the roughened copper surface is larger than that of Blending 1 to Blending 11, and the formation of the roughening shape is insufficient.

Formula 18, Formula 19 (see Figure 10 and Figure 11) containing polymer F (non-ionic surfactant without quaternary ammonium salt) and Formula H containing low molecular weight polyethylenimine In Blend 22 and Blend 23 (Figures 14 and 15), at any polymer concentration, the surface was hardly roughened, showing a larger L ^* value than Blend 12 without polymer. In the formulation 24 and formulation 25 of Polymer I (derivative polymer of ethylenediamine), the copper surface was not roughened at any polymer concentration.

From these results, it can be seen that when a polymer having a quaternary ammonium group in the side chain is used, and an inorganic acid-based solution containing a copper ion, a halide ion, and a polymer compound ratio within a predetermined range is used, it is particularly possible A fine uneven shape with excellent adhesion is formed on the copper surface.

The L ^* value of the roughened copper surface is adjusted to the buffered pH (the same pH as the pKa of the organic acid) of the organic acid solution of the adjustment 26 and the adjustment 27 by adding an organic acid, compared with the adjustment 1 to the adjustment 11 Large, insufficiently formed roughened shapes. One reason for the insufficient formation of the roughened shape is that the pH is high and the solubility of copper ions generated by etching is low. In addition, it is considered that organic acids are easily coordinated to copper ions. Therefore, in the solutions of Preparation Example 26 and Preparation Example 27, the effective concentration of copper ions is reduced, and the balance between the concentration of copper ions and halide ions is destroyed. full.

Claims (8)

    A micro-etching agent, a copper micro-etching agent for roughening the surface of copper, and containing inorganic acids, copper ions, halide ions, and cationic polymers; the aforementioned cationic polymers contain four levels on the side chain A water-soluble polymer with an ammonium group and a weight average molecular weight of 1000 or more; the molar concentration of halide ions is 5 to 100 times the molar concentration of copper ions; the pH is 2 or less.         The micro-etching agent as described in claim 1, wherein the molar concentration of copper ions is 0.001 mol / L to 0.5 mol / L.         The micro-etching agent as described in claim 1 or 2, wherein the molar concentration of the halide ion is 0.01 mol / L to 10 mol / L.         The micro-etching agent according to claim 1 or 2, wherein the weight concentration of the aforementioned polymer is 0.0005 g / L to 0.5 g / L.         The micro-etching agent as described in claim 1 or 2, wherein the weight concentration of copper ions is 50 times to 2000 times the weight concentration of the aforementioned polymer.         A method of manufacturing a wiring board, which manufactures a wiring board including a copper layer, and has a roughening process step of contacting the copper surface with a micro-etching agent as described in any one of claims 1 to 5 The copper surface is roughened.         The method of manufacturing a wiring board according to claim 6, wherein the average etching amount in the depth direction when the copper surface is roughened is 1 μm or less.         The method of manufacturing a wiring board according to claim 6 or 7, wherein in the roughening treatment step, a replenishing liquid is added to the micro-etching agent, and the replenishing liquid is composed of a mineral acid, halide ion, and polymer. Acidic aqueous solution composition; The polymer in the replenishment solution is a water-soluble polymer containing a quaternary ammonium group in the side chain and having a weight average molecular weight of 1,000 or more.