KR102124328B1 - Micro-roughening composition for increasing adhesion of copper metal surface - Google Patents

Abstract

Provided is a composition for forming fine roughness for increasing adhesion on a copper surface at a low etch rate, including: an etchant containing at least one alkaline compound selected from a group consisting of alkali metal hydroxide, alkaline earth metal hydroxide, and ammonium hydroxide; a roughness increasing additive containing an aliphatic amine compound and an oxidizing agent; and water.

Description

Micro-roughening composition for increasing adhesion of copper metal surface

The technology disclosed herein relates to a composition for forming a fine roughness for improving adhesion of a copper metal surface, and more particularly, to a composition for forming a fine roughness capable of increasing the adhesion of a dry film by forming the fine roughness of a copper metal surface. .

Copper or copper alloy etching technology is used in a wide range of fields, and thus is an essential technology in electronic and electrical component manufacturing, such as ornaments, resource recovery, semiconductor manufacturing, and printed wiring board manufacturing. For etching, to remove contaminants or oxide films on the surface of copper or copper alloy, to flatten unevenness on the surface of copper or copper alloy, and to form a protective film on the surface of copper or copper alloy, such as when forming wiring patterns. For dissolving and removing the exposed portions of the copper or copper alloy that are not covered by the protective film, for dissolving the entire copper or copper alloy on the surface, and for adhering the resist or the like to roughen the surface of the copper or copper alloy. Etching has several purposes, such as things. Among them, soft etching is an etching method used to attach a resist such as a dry film by forming irregularities on the surface of copper.

In order to pattern a circuit on a printed circuit board in a printed circuit board process, a process of attaching an infrared photosensitive polymer film dry film to a substrate surface is required. In a printed circuit board such as a multilayer printed circuit board, in order to improve adhesion (adhesiveness) of a copper metal circuit to a dry film, it is necessary to form a fine surface roughness by etching the copper printed circuit board by an oxidative method. At this time, the soft etching is to increase the adhesion of the dry film to the substrate, and is a pre-treatment process performed before the dry film is attached to the substrate. Therefore, by performing the soft etching using the soft etching solution, it is possible to form a fine unevenness on the copper surface to increase the adhesion of the dry film attached to the patterning, and to obtain an effect of removing contaminants. As the soft etchant, a solution containing hydrogen peroxide-sulfuric acid is used, and an additive for controlling the etch rate can be additionally added to the solution so that etching can be effectively performed.

However, when soft etching is performed with the solution in a situation in which a fine wiring pattern is required due to the trend of weight reduction of a printed circuit board, it is difficult to control the amount of etching, and there is a limit in obtaining high adhesion between the substrate and the dry film. have.

Republic of Korea Patent Publication No. 1999-0045461

According to one aspect of the technology disclosed herein, in a fine roughness forming composition capable of forming a copper surface roughness at a low etch rate to increase adhesion to a dry film as a resist, alkali metal hydroxide, alkaline earth metal hydroxide and ammonium An etchant comprising at least one alkaline compound selected from the group consisting of hydroxides; An illuminance increasing additive comprising an aliphatic amine compound and an oxidizing agent; And it is provided a fine roughness-forming composition comprising water.

According to another aspect of the technology disclosed herein, (a) providing a copper substrate; (b) treating the copper substrate with a fine roughness forming composition to form irregularities on the surface; (c) washing and drying the copper substrate, wherein the fine roughness-forming composition comprises an etchant containing at least one alkaline compound selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides and ammonium hydroxide. ; An illuminance increasing additive comprising an aliphatic amine compound and an oxidizing agent; And it provides a method of roughening the surface of a copper substrate comprising water.

According to another aspect of the technology disclosed herein, (a) providing a copper substrate; (b) treating the copper substrate with a fine roughness forming composition to form irregularities on the surface; (c) washing and drying the copper substrate; And (d) attaching a dry film to the copper substrate, wherein the fine roughness-forming composition comprises at least one alkaline compound selected from the group consisting of alkali metal hydroxide, alkaline earth metal hydroxide and ammonium hydroxide. Etchant; An illuminance increasing additive comprising an aliphatic amine compound and an oxidizing agent; And a method for attaching a dry film to a copper substrate comprising water.

1 illustrates a mechanism in which roughness is formed on a copper surface with a fine roughness-forming composition according to one embodiment of the technology disclosed herein.
Figure 2 shows the expected results when forming the roughness on the copper surface with a fine roughness forming composition and a conventional soft etchant according to an embodiment of the technology disclosed herein.
3 illustrates a surface roughening process of a copper substrate according to one embodiment of the technology disclosed herein.
Figure 4 shows the results of Experimental Example 1 disclosed herein.
Figure 5 shows the results of Experimental Example 3 disclosed herein.

The present invention can be applied to various changes and can have various forms, and the embodiments are described in detail in the text. However, this is not intended to limit the present invention to a specific disclosure form, and it should be understood as including all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

In describing each drawing, similar reference numerals are used for similar components. Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from other components. The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, terms such as “comprises” or “consisting of” are intended to indicate the presence of features, numbers, steps, operations, components, parts or combinations thereof described in the specification, one or more other features. It should be understood that the existence or addition possibilities of fields or numbers, steps, actions, components, parts or combinations thereof are not excluded in advance.

According to one embodiment of the technology disclosed herein, a composition for forming a fine roughness to form copper surface roughness at a low etch rate is provided. The fine roughness-forming composition essentially includes an etchant (roughness-forming agent), a roughness increasing additive, and water.

The etchant may include an alkaline compound. The alkaline compound forms a base that enables low etching on the copper surface, and when copper is dissolved, may help in the ionization role. It can also increase the cleaning effect of the copper surface.

The alkaline compound may be at least one selected from the group consisting of alkali metal hydroxide, alkaline earth metal hydroxide and ammonium hydroxide. Examples of the alkaline compound, specifically, the group consisting of sodium hydroxide (NaOH), potassium hydroxide (KOH), ammonium hydroxide (NH ₄ OH), calcium hydroxide (Ca(OH) ₂ ) and barium hydroxide (Ba(OH) ₂ ) It may be one or more selected from.

The etchant containing the alkaline compound may be included in 5 to 30% by weight, preferably 10 to 20% by weight of the total fine roughness forming composition. Copper is stably dissolved within the above range, and fine roughness may be formed. If it is outside the above range, the etching rate may be increased or stains may be generated on the copper surface.

The roughness increasing additive includes an aliphatic amine compound and an oxidizing agent. The roughness increasing additive helps the oxidation reaction of the copper surface, and can form a uniform surface texture.

The aliphatic amine compound may contain 1 to 12 carbon atoms in the chain, and may preferably have a molecular weight of 60 to 200 g/mol. Specifically, the aliphatic amine compound may be at least one selected from the group consisting of alkanol amine compounds and diamines. The alkanol amine compound may have 1 to 3 -OH at the terminal. The diamine may have each terminal -NH ₂ and may include 0 to 3 -NH- in the middle of the chain. Examples of the aliphatic amine compound are specifically, monoethanol amine, diethanol amine, triethanol amine, propanol amine, dipropanol amine, tripropanol amine, isopropanol amine, diisopropanol amine, triisopropanol amine, N-ethylethanol amine, N-butylethanol amine, N-methylethanol amine, (2-aminoethoxy)-1-ethanol, aminoethylethanolamine, methyl diethanolamine, diethylaminoethanol, ethylene diamine, diethylene triamine and triethylene It may be two or more selected from the group consisting of tetraamines. Preferably, the aliphatic amine compound is a mixture of triethanol amine and ethylenediamine Can be

The oxidizing agent is a peroxide; Salts of chlorite, chlorate or perchlorate; Hypochlorite compounds; Persulfate compounds; Sodium perborate; Organic sulfonic acid; It may be one or more selected from the group consisting of a ferric compound and a cupric compound. Examples of the oxidizing agent may be specifically peroxide. Preferably, the oxidizing agent may be hydrogen peroxide.

The aliphatic amine compound can be used together with the oxidizing agent to improve copper surface roughness by increasing copper attack. Depending on the concentration of the oxidizing agent, the etching time may be about 1 to 10 minutes, and preferably 1 to 5 minutes. Fine roughness required in the above range can be formed.

The roughness increasing additive may be included in 1 to 20% by weight, preferably 5 to 10% by weight of the total fine roughness forming composition. In addition, based on the total weight of the aliphatic amine compound, the oxidizing agent may be included in 10 to 20% by weight. It is possible to form a uniform fine copper surface structure while exhibiting a low etching rate within the above range.

According to one embodiment of the technology disclosed herein, the fine roughness-forming composition may further include an etch inhibitor and an etch rate modifier.

The etch inhibitor may be included for the purpose of forming a uniform roughness on the copper surface. Specifically, when the etching inhibitor is included, organic substances are finely adsorbed on the copper surface to form a uniform roughness during etching, and it is possible to prevent excessive etching. The etching inhibitor may include an azole-based compound. The azole compounds are 5-amino-1H-tetrazole, 1H-tetrazole, 5-phenyl-1H-tetrazole, benzothiazole, sodium tolyltriazole, benzotriazole, imidazole, 3-amino-1, It may be one or more selected from the group consisting of 2,4-triazole sulfathiazole and carboxycitazole. Preferably, the azole-based compound may be benzotriazole.

The etch inhibitor may be included in an amount of 0.1 to 2% by weight, preferably 0.2 to 1% by weight of the total fine roughness forming composition. Improved fine roughness within the above range can be implemented to improve the adhesion (adhesion) of the dry film to the copper surface, and it is possible to prevent the phenomenon that the etching is rapidly increased even when the treatment time is increased. If it is out of the above range, the etching amount of copper may be reduced.

The etch rate modifier serves as an auxiliary of an etch inhibitor and may be included for the purpose of preventing excessive etching. The etch rate modifier may include an organic hydroxide-based compound. Examples of the organic hydroxide-based compound, specifically, may be tetraalkylammonium hydroxide. Preferably, the organic hydroxide-based compound is a group consisting of tetramethylammonium hydroxide, tetraethylammonium hydroxide, ethyltrimethylammonium hydroxide, dimethylpropylammonium hydroxide and tetrabutylammonium hydroxide It may be one or more selected.

The etch rate adjusting agent may be included in 1 to 10% by weight, preferably 2 to 6% by weight of the total fine roughness forming composition. Within the above range, while the auxiliary role of the etching inhibitor is smoothly performed, excessive etching may be prevented.

The water may be pure water, ultrapure water, or deionized water (DI water). The water may be included in 70 to 99% by weight, preferably 85 to 95% by weight of the total fine roughness forming composition.

According to one embodiment of the technology disclosed herein, the fine roughness forming composition may further include a surfactant and a water-miscible organic solvent.

The surfactant may be anionic, cationic or nonionic surfactant. Examples of such surfactants include, specifically, dodecyl sulfate sodium salt, sodium lauryl sulfate, dodecyl sulfate ammonium salt, secondary alkane sulfonate (SAS), alkyl phenol ethoxylate, fatty alcohol ethoxylate, fatty amine It may be one or more selected from the group consisting of toxlate and propylene oxide-ethylene oxide block copolymers.

The surfactant may be included in less than 2% by weight, preferably 0.001 to 1% by weight of the total fine roughness forming composition.

Examples of the water-miscible organic solvent are specifically, ethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, tripropylene glycol methyl ether, tripropylene glycol monobutyl ether, propylene glycol propyl ether, diethylene glycol It may be one or more selected from the group consisting of n-butyl ether, hexyloxypropylamine, poly(oxyethylene)diamine, dimethyl sulfoxide, tetrahydrofurfuryl alcohol, glycerol, benzyl alcohol and sulfoxide.

The water-miscible organic solvent may be included in 0.1 to 10% by weight of the total fine roughness forming composition.

According to one embodiment of the technology disclosed herein, when etching the copper surface with the fine roughness forming composition, it is possible to provide a low copper etching amount of 0.1 to 0.5 μm. In addition, the fine roughness forming composition may exhibit a low etch rate of 0.1 to 0.2 ㎛ / min. Within this range, a uniform fine surface structure and low surface roughness may be formed on the copper surface, and the copper surface area may be increased by the formed fine surface structure, thereby increasing adhesion to the dry film.

According to one embodiment of the technology disclosed herein, a mechanism for etching a copper surface with the fine roughness forming composition may be described in the following steps with reference to FIG. 1.

First, in step S1), -NH ₂ derived from the aliphatic amine compound included in the fine roughness-forming composition is regularly arranged and bonded to the copper surface. Next, in step S2), a functional group (R+) derived from an etch inhibitor bonds between -NH ₂ bound to the copper surface to maintain a form capable of forming a fine surface tissue. Subsequently, in step S3), a low etching of the copper surface is achieved through a cutting agent and an oxidizing agent. Due to the above steps, it is possible to realize a copper surface having a uniform and fine surface texture and roughness even at a low etch rate.

According to an embodiment of the technology disclosed in the present disclosure, when comparing the surface of the copper etching with a fine roughening composition and the case of etching the copper surface with a conventional soft etching solution, the results shown in FIG. 2 can be expected. . That is, referring to FIG. 2, the leftmost part is a copper cross section before etching, the center is a copper cross section after etching with a conventional soft etching solution, and the rightmost figure shows a copper cross section after etching with the fine roughness forming composition. will be. Based on the results of FIG. 2, when using the alkali-based fine roughness forming composition, it can be expected that the fine pattern shape will be maintained better than the conventional soft etchant.

When the copper surface is etched with the fine roughness forming composition as described above, roughness (irregularity) can be effectively formed on the copper surface without changing the overall pattern shape during the etching process. As a result, the adhesion of the dry film to the copper surface can be further improved. Specifically, the above-described fine roughness forming composition may include an alkaline etchant and an additive for increasing roughness to obtain a high adhesion result with a dry film while maintaining pattern formation at a low etch rate. In addition, it is possible to form a fine circuit by forming a fine roughness in the thin copper chemical layer or the copper electrode layer.

On the other hand, according to one embodiment of the technology disclosed in the present specification, there is provided a method for roughening the surface of a copper substrate capable of increasing adhesion to a dry film using the above-described fine roughness forming composition. The method of roughening the surface of the copper substrate may include (a) providing a copper substrate; (b) etching the copper substrate with a fine roughness forming composition to form irregularities on the surface; And (c) washing and drying the copper substrate (see FIG. 3).

The fine roughness-forming composition may include an etchant containing at least one alkaline compound selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides and ammonium hydroxides; An illuminance increasing additive comprising an aliphatic amine compound and an oxidizing agent; And water. Preferably, the fine roughness-forming composition comprises an etch inhibitor comprising an azole-based compound; And it may further include an etch rate modifier comprising an organic hydroxide-based compound.

The etchant, the roughness increasing additive, the etch inhibitor, the etch rate regulator and the detailed description of the water is already described above, so it will be omitted.

According to one embodiment of the technology disclosed herein, the step of (a) may further include the step of washing the copper substrate by degreasing, pickling or washing. This is for completely removing the holding component on the surface of the copper substrate and removing the excess surface oxide film. The pickling is intended to be cleaned by passing the copper substrate through the pickling treatment tank, whereby uniform electrodeposition and the like can be secured in the following process. For the pickling, a hydrochloric acid solution, a sulfuric acid solution, a sulfuric acid-hydrogen peroxide solution, or the like can be used. At this time, the concentration or temperature of the solution can be appropriately adjusted according to the characteristics of the production line.

After the step (b), an anti-tarnishing step may be further included to prevent oxidation and increase adhesion to the dry film. Through this, an organic coating layer layer may be formed on the surface of the copper substrate.

According to one embodiment of the technology disclosed herein, the etching thickness when etching the copper substrate using the fine roughness forming composition in step (b) may be 0.1 to 0.5 μm. In addition, the roughness formed on the surface of the etched copper substrate may be 0.1 to 0.5 μm as a Ra value, preferably 0.1 to 0.3 μm, and more preferably 0.1 to 0.2 μm. It is possible to prevent stains from occurring on the surface of the copper substrate while securing adhesion to the dry film within the above range.

In addition, according to an embodiment of the technology disclosed herein, a method for attaching a dry film to a copper substrate using the above-described fine roughness forming composition is provided. The method of attaching a dry film to the copper substrate includes (a) providing a copper substrate; (b) etching the copper substrate with a fine roughness forming composition to form irregularities on the surface; (c) washing and drying the copper substrate; And (d) attaching a dry film to the copper substrate. Since the detailed description of the fine roughness forming composition has already been described above, it will be omitted.

After the step (b), an anti-tarnishing step may be further included to prevent oxidation and increase adhesion to the dry film. Through this, an anti-corrosive coating layer formed of an organic coating layer may be formed on the surface of the copper substrate.

Hereinafter, the technology disclosed in the present specification will be described through specific embodiments, and this is for convenience of description of the presently disclosed technology, and the spirit of the disclosed technology is not limited thereto.

[Examples 1 to 7 and Comparative Examples 1 to 3]

A composition for forming a fine roughness having the composition (each component content unit: weight %) of Table 1 below was prepared.

division Etchant Illumination increasing additive Etch inhibitor Etch rate
Modulator water Aliphatic amine compounds Oxidizer Example 1 NaOH
10% Triethanol amine
5% H ₂ O ₂
5% 1H-tetrazol
0.5% TMAH
3% 76.5% Example 2 NaOH
10% Diethanolamine
5% H ₂ O ₂
3% Benzotriazole
0.5% TMAH
3% 78.5% Example 3 NaOH
5% Diethanolamine
2% H ₂ O ₂
3% 5-amino-1H-tetrazole
0.5% TMAH
3% 86.5% Example 4 NaOH
10% Diethanolamine
5% H ₂ O ₂
3% 5-amino-1H-tetrazole
0.5% TMAH
3% 78.5% Example 5 NaOH
15% Monoethanolamine
10% H ₂ O ₂
3% Sodium tolyltriazole
0.5% TMAH
3% 68.5% Example 6 KOH
15% Monoethanolamine
10% H ₂ O ₂
3% Sodium tolyltriazole
0.5% TMAH
3% 68.5% Example 7 NaOH
10% Monoethanolamine
5% H ₂ O ₂
3% Benzotriazole
0.7% TMAH
3% 78.3% Comparative Example 1 H ₂ SO ₄
3% - H ₂ O ₂
5% - - 92.0% Comparative Example 2 NaOH
15% - H ₂ O ₂
5% 1H-tetrazol
0.5% TMAH
3% 76.5% Comparative Example 3 NaOH
15% - H ₂ O ₂
3% Benzotriazole
0.5% TMAH
3% 78.5%

[Experimental Example 1] Evaluation of formation of fine roughness

A sample having a size of 30 μm (thickness) × 10 cm (horizontal) × 10 cm (vertical) consisting of chemical copper plating (Point 1) and electrolytic copper plating (Point 2) was used as the composition for forming fine roughness of Example 7 and Comparative Example 2. Each was etched using a spray device (pressure: 1.0-1.5 MPa). After etching, the surface of each specimen was checked with a scanning electron microscope (SME), and the results are shown in FIG. 4.

Referring to FIG. 4, it was confirmed that finer roughness (irregularity) was formed on the surface of the specimen etched with Example 7, which is the composition for forming fine roughness of the present invention, compared to the specimen etched with Comparative Example 2. This is to support the fact that the fine roughness-forming composition according to the present invention can form fine surface roughness.

[Experimental Example 2] Etch rate measurement

Copper samples of 10 cm (horizontal) x 10 cm (vertical) with the fine roughness-forming composition of Examples 1 to 7 and Comparative Examples 1 to 3 were etched with a spray device (pressure: 1.0-1.5 MPa) for 3 minutes, respectively. After washing and drying, the copper specimens were weighed respectively. Then, the etch rate (E/R) was calculated by Equation 1 below, and the results are shown in Table 2 below. In order to form a uniform fine roughness at a low etch rate, the etch rate was set to 0.3 µm or less.

[Equation 1]

Etch rate (㎛) = {Weight of copper specimen before etching (g)-weight of copper specimen after etching (g)}×10,000/{width (cm) of copper specimen × length (cm) of copper specimen ×2 (both sides) × Specific gravity of copper specimens}

[Experimental Example 3] Measurement of adhesion

Copper samples of 10 cm (horizontal) x 10 cm (vertical) with the fine roughness forming compositions of Examples 1 to 7 and Comparative Examples 1 to 3 were etched with a spray device (pressure: 1.0-1.5 MPa), respectively. At this time, the etching rate was 0.2 µm. Next, a 15 μm thick dry film was laminated on the surface of each etched copper specimen at a temperature of 110° C. and a pressure of 4 bar, and then exposed to 180 m/J to develop. Then, a 3M tape having a width of 18 mm and a length of 10 cm was attached to the developed dry film, and the tape was teared off with a constant force to evaluate the degree of dropping of the dry film from the surface of the copper specimen, and the results are shown in Table 2 below. Shown. At this time, the measurement criteria of the adhesion between the surface of the copper specimen and the dry film were as follows.

-×: Poor, 10% or more of dry film fell off

-○: Normal, 1~5% off of dry film

-◎: Good, no dry film fall

On the other hand, the surface of the copper specimen was etched with the fine roughness forming compositions of Examples 7, Comparative Examples 1 and 2, respectively, and the results of forming a fine pattern using a dry film are shown in FIG. 5.

division Etch rate (㎛) Adhesion measurement Example 1 0.45 ○ Example 2 0.62 ◎ Example 3 0.20 ○ Example 4 0.30 ○ Example 5 0.42 ◎ Example 6 0.38 ○ Example 7 0.20 ◎ Comparative Example 1 1.00 × Comparative Example 2 0.55 × Comparative Example 3 0.24 ×

Referring to Table 2, Examples 1 to 7, which are compositions for forming a fine roughness of the present invention, can form a uniform fine roughness on the surface of a copper specimen even at a low etch rate, thereby increasing adhesion to a dry film. I could confirm that.

Also, referring to FIG. 5, it was confirmed that a clear fine pattern was formed by Example 7, which is a fine roughness forming composition of the present invention.

Claims (12)

In the composition for forming a fine roughness to form a copper surface roughness at a low etch rate,
An etchant containing at least one alkaline compound selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides and ammonium hydroxides;
Illuminance increasing additives including aliphatic amine compounds and oxidizing agents;
water;
An etch inhibitor comprising an azole compound; And
It includes an etch rate regulator comprising an organic hydroxide-based compound,
The etchant is a fine roughness forming composition that is included in 5 to 30% by weight of the total fine roughness forming composition. delete According to claim 1,
The aliphatic amine compound is one or more selected from the group consisting of alkanol amine compounds and diamines fine roughness forming composition. According to claim 1,
The oxidizing agent is a peroxide; Salts of chlorite, chlorate or perchlorate; Hypochlorite compounds; Persulfate compounds; Sodium perborate; Organic sulfonic acid; Ferric compounds; And one or more selected from the group consisting of cupric compounds. According to claim 1,
The azole compound is 5-amino-1H-tetrazole, 1H-tetrazole, 5-phenyl-1H-tetrazole, benzothiazole, sodium tolyltriazole, benzotriazole, imidazole, 3-amino-1, Fine roughness forming composition which is at least one member selected from the group consisting of 2,4-triazole, sulfazazole and carboxycitazole. According to claim 1,
The organic hydroxide-based compound is at least one member selected from the group consisting of tetramethylammonium hydroxide, tetraethylammonium hydroxide and tetrabutylammonium hydroxide. (a) providing a copper substrate;
(b) etching the copper substrate with a fine roughness forming composition to form irregularities on the surface; And
(c) washing and drying the copper substrate,
The fine roughness-forming composition may include an etchant containing at least one alkaline compound selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides, and ammonium hydroxides; An illuminance increasing additive comprising an aliphatic amine compound and an oxidizing agent; water; An etch inhibitor comprising an azole compound; And an etch rate modifier comprising an organic hydroxide-based compound,
The etching agent is a method of roughening the surface of the copper substrate that is included in 5 to 30% by weight of the total fine roughness forming composition. The method of claim 7,
The method of roughening the surface of a copper substrate further comprising the step of washing the copper substrate before the step (a). The method of claim 7,
The method of roughening the surface of a copper substrate further comprising the step of rust-preventing after the step (b). The method of claim 7,
The etching thickness is 0.1 to 0.5 ㎛ surface roughness method of the copper substrate. delete (a) providing a copper substrate;
(b) etching the copper substrate with a fine roughness forming composition to form irregularities on the surface;
(c) washing and drying the copper substrate; And
(d) attaching a dry film to the copper substrate,
The fine roughness-forming composition may include an etchant containing at least one alkaline compound selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides and ammonium hydroxides; An illuminance increasing additive comprising an aliphatic amine compound and an oxidizing agent; water; An etch inhibitor comprising an azole compound; And an etch rate modifier comprising an organic hydroxide-based compound,
The etching agent is a method of attaching a dry film to a copper substrate, which is included in 5 to 30% by weight of the total fine roughness forming composition.

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