Additive for electroplating solution, electroplating solution, electroplating method, and method for manufacturing metal layer

Abstract

Provided is an additive for an electroplating solution, the additive containing a reaction product between at least one type of epoxy compound (a1) represented by general formula (1) and at least one type of tertiary amine compound (a2).　[Chemical 1] (In the formula, L1 and L2 each independently denote a hydrogen atom, an alkyl group having 1-5 carbons, or a group represented by general formulas (L-1) to (L-3), and n denotes an integer of 1-5.)　[Chemical 2] (In the formula, m1 to m3 each independently denote an integer of 1-5, and * denotes a bond.)

Description

Additive for electrolytic plating solution, electrolytic plating solution, electrolytic plating method, and method for producing metal layer

[0001] The present invention relates to an additive for an electrolytic plating solution containing a reaction product of an epoxy compound having a specific structure and a tertiary amine compound, an electrolytic plating solution containing the additive for an electrolytic plating solution, an electrolytic plating method using the electrolytic plating solution, and a method for producing a metal layer using the electrolytic plating method.

[0002] Conventionally, techniques for filling patterns such as grooves and holes with metal have been used to form fine wiring, through silicon vias (TSVs), and bumps in highly integrated electronic circuits. Electroplating is one of the most common metal filling techniques, and electrolytic copper plating, which fills copper as the metal, is particularly well-known. Conventional electrolytic copper plating has been problematic in that the thickness of the filled copper layer is not uniform and voids are formed inside the grooves and holes, resulting in poor circuit connections. To address these issues, additives such as levelers and inhibitors have been introduced into the electrolytic copper plating solution, which act to increase the filling rate and improve thickness uniformity, thereby enabling copper to be filled.

[0003] Common additives used in electroplating solutions include polyethyleneimine, polyaniline, polyacrylamide, polyvinylpyridine, polyvinylimidazole, polyvinylpyrrolidone, and polyacrylamide. For example, Patent Document 1 discloses polyvinylpyrrolidone as a leveling agent used in an aqueous electroplating solution for embedding fine copper wiring. Patent Document 2 discloses polyethyleneimine as a leveling agent used in a copper plating solution for forming a copper film. Patent Document 3 discloses polyethyleneimine as a leveling agent used in a non-cyanide acidic silver plating bath. It is also known to use a reaction product of an epoxy compound and an amine compound as an additive for electroplating solutions in order to obtain a metal layer with a highly uniform thickness. For example, Patent Document 4 discloses a reaction product of 1,4-butanediol diglycidyl ether and 2,4-dimethylimidazole as a leveling agent. Patent Document 5 discloses a reaction product of glycerol diglycidyl ether and imidazole. Furthermore, Patent Document 6 discloses a reaction product of 1,4-butanediol diglycidyl ether with N-methylaniline or diphenylamine.

[0004] International Publication No. 2011 / 001847 JP 2014-185390 A JP 2007-327127 A JP 2011-190260 A JP 2017-36500 A JP 2017-61487 A

[0005] However, when a metal layer is formed by an electrolytic plating method using an electrolytic plating solution containing the leveling agent described in Patent Documents 1 to 6, the embedding rate and thickness uniformity of the metal layer are not sufficient.

[0006] Therefore, an object of the present invention is to provide an additive for an electroplating solution that can form a metal layer with a high embedding rate and high thickness uniformity.

[0007] As a result of extensive investigations, the present inventors have found that the above-mentioned problems can be solved by using a compound obtained by reacting an epoxy compound having a specific structure with a tertiary amine compound as an additive for an electroplating solution, and have arrived at the present invention.

[0008] That is, the present invention provides an additive for an electroplating solution containing a reaction product of at least one epoxy compound (a1) represented by the following general formula (1) and at least one tertiary amine compound (a2):

[0009]

[0010] (In the formula, L 1 and L 2 each independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a group represented by the following general formulas (L-1) to (L-3), and n represents an integer of 1 to 5.

[0011]

[0012] (In the formula, m 1 ~m 3 each independently represents an integer of 1 to 5, and * represents a bond.

[0013] The present invention is an electroplating solution containing the above-mentioned additive for electroplating solutions.

[0014] The present invention is an electrolytic plating method using the above electrolytic plating solution.

[0015] The present invention is a method for producing a metal layer using the above electrolytic plating method.

[0016] According to the present invention, an additive for an electroplating solution can be provided that is capable of forming a metal layer with a high embedding rate and a highly uniform thickness.

[0017] FIG. 2 is a schematic cross-sectional view of a substrate after a copper layer has been formed on the surface of the substrate by an electrolytic plating method in an evaluation test.

[0018] <Additive for Electroplating Solution> The additive for electroplating solution of the present invention contains a reaction product of at least one epoxy compound (a1) represented by the above general formula (1) and at least one tertiary amine compound (a2).

[0019] In the above general formula (1), L 1 and L 2 each independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a group represented by any one of the general formulae (L-1) to (L-3) above; and n represents an integer of 1 to 5.

[0020] Specific examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group.

[0021] In the above general formulae (L-1) to (L-3), m 1 , m 2 and m 3 each independently represents an integer of 1 to 5, and * represents a bond.

[0022] From the viewpoint of being able to form a metal layer with a high embedding rate and a high uniformity in thickness, 1 is preferably a group represented by general formula (L-3). From the viewpoint of being able to form a metal layer with a high embedding rate and a high uniformity in thickness, L 2 is preferably a group represented by general formula (L-2) or (L-3), and more preferably a group represented by general formula (L-3). From the viewpoint of being able to form a metal layer with a high embedding rate and a high uniformity in thickness, n is preferably an integer of 1 to 3, and more preferably an integer of 1 to 2. From the viewpoint of being able to form a metal layer with a high embedding rate and a high uniformity in thickness, m 1 , m 2 and m 3 is preferably an integer of 1 to 3, and more preferably an integer of 1 or 2.

[0023] Preferred specific examples of the epoxy compound (a1) represented by the general formula (1) include the following epoxy compounds No. 1 to No. 16.

[0024]

[0025]

[0026] Among these epoxy compounds (a1), the epoxy compound No. 13 (triglycidyl isocyanurate) is more preferred from the viewpoint of being able to form a metal layer with a higher embedding rate and a more uniform thickness.

[0027] As the tertiary amine compound (a2), well-known general tertiary amine compounds can be used, and specific examples include trialkylamine compounds and azole compounds. Specific examples of trialkylamine compounds include trimethylamine, triethylamine, tripropylamine, tributylamine, dimethylethylamine, and diethylmethylamine. Specific examples of azole compounds include pyrrole, imidazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole, pyrazole, oxazole, isoxazole, thiazole, isothiazole, oxadiazole, thiadiazole, dihydrooxazole, tetrahydrooxazole (oxazolidine), dihydroisoxazole, tetrahydroisoxazole (isoxazolidine), dihydrothiazole, tetrahydrothiazole (thiazolidine), dihydroisothiazole, tetrahydroisothiazole (isothiazolidine), dihydrooxadiazole, tetrahydrooxazole (oxaz ...isothiazole, tetrahydrooxadiazole, tetrahydrooxazole (oxazolidine), dihydroisothiazole, tetrahydroisothiazole (isothiazolidine), dihydroisothiazole, tetrahydrooxadiazole, tetrahydrooxazole (oxazolidine), dihydroisothiazole, tetrahydroisothiazole (isothiazolidine), dihydroisothiazole, tetrahydrooxadiazole, tetrahydrooxazole (oxazolidine), dihydro Examples of such an alkyl benzoate include hydroxadiazole (oxadiazolidine), dihydrothiadiazole, tetrahydrothiadiazole (thiadiazolidine), isoindole, indazole, benzoxazole, benzothiazole, benzimidazole, benzothiadiazole, benzotriazole, dihydroindazole, perhydroindazole, dihydrobenzoxazole, perhydrobenzoxazole, dihydrobenzothiazole, perhydrobenzothiazole, dihydrobenzimidazole, perhydrobenzimidazole, tetrahydrobenzimidazole, and benzisoxazole.

[0028] From the viewpoint of being able to form a metal layer having a high embedding rate and a high uniformity in thickness, the tertiary amine compound (a2) is preferably an azole compound, more preferably an azole compound selected from the group consisting of imidazole, pyrazole, isothiazole, isoxazole, 1,2,3-triazole, 1,2,4-triazole, and benzimidazole, even more preferably imidazole or benzimidazole, and most preferably imidazole.

[0029] The reaction product contained in the electroplating solution additive of the present invention is produced by reacting at least one epoxy compound (a1) represented by the general formula (1) with at least one tertiary amine compound (a2). The epoxy compound (a1) represented by the general formula (1) may be used alone or in combination of two or more. The tertiary amine compound (a2) may be used alone or in combination of two or more. The production method is not particularly limited except for the reaction of component (a1) with component (a2). For example, the reaction product can be obtained by mixing component (a1) with component (a2) in an aqueous diethylene glycol solution, heating, stirring, filtering, and then removing the solvent. From the viewpoint of reducing unreacted materials, the heating temperature is preferably 50 to 200°C, more preferably 70 to 150°C. From the viewpoint of reducing unreacted materials, the heating time is preferably 30 minutes to 10 hours, more preferably 1 to 5 hours.

[0030] From the viewpoint of being able to form a metal layer having a large embedding rate and a high uniformity in thickness, the molar ratio of the component (a1) to the total of the component (a1) and the component (a2) [component (a1) / (component (a1)+component (a2)] is preferably 0.05 to 0.95, more preferably 0.1 to 0.8, and most preferably 0.2 to 0.6.

[0031] By using an electroplating method that uses an electroplating solution containing the additive for electroplating solution of the present invention, which contains the above-mentioned reaction product, it is possible to form a metal layer on a substrate with a high embedment rate and high thickness uniformity. In particular, by using an electroplating method that uses an electroplating solution containing the additive for electroplating solution of the present invention, it is possible to form a metal layer with a high embedment rate and high thickness uniformity even on a substrate having a fine structure (e.g., grooves or holes) on the surface. Furthermore, when added to an electroplating copper plating solution, the additive for electroplating solution of the present invention is particularly suitable as an additive for an electrolytic copper plating solution because the copper layer obtained has a very high embedment rate and very high thickness uniformity.

[0032] <Electrolytic Plating Solution> Next, the electrolytic plating solution of the present invention will be described. The electrolytic plating solution of the present invention is an aqueous solution containing the above-mentioned electrolytic plating solution additive as an essential active ingredient. From the viewpoint of further enhancing the effects of the present invention, the concentration of the electrolytic plating solution additive in the electrolytic plating solution is preferably 1 mg / L to 1000 mg / L, more preferably 10 mg / L to 500 mg / L, and even more preferably 20 mg / L to 300 mg / L.

[0033] The electroplating solution of the present invention may contain, as components other than the above-mentioned electroplating solution additive, metal salts serving as metal supply sources, electrolytes, chloride ion sources, plating accelerators, plating suppressors, etc., similar to conventionally known electroplating solutions.

[0034] The metal of the metal salt used in the electrolytic plating solution of the present invention is not particularly limited as long as it is a metal that can be used to form a film by an electrolytic plating method, and examples thereof include copper, tin, silver, etc. In particular, when the electrolytic plating solution additive of the present invention is used in an electrolytic copper plating solution, the thickness of the obtained copper layer becomes more uniform, which is preferable. Examples of copper salts that can be added to the electrolytic copper plating solution include copper sulfate, copper acetate, copper fluoroborate, and copper nitrate.

[0035] Examples of inorganic acids that serve as electrolytes in the electroplating solution of the present invention include sulfuric acid, phosphoric acid, nitric acid, hydrogen halides, sulfamic acid, boric acid, and fluoroboric acid.

[0036] The electrolytic plating solution of the present invention is preferably used as a copper sulfate and sulfuric acid-based electrolytic copper plating solution because the resulting copper layer has excellent surface smoothness. In this case, the concentration of copper sulfate (as CuSO4.5H2O) in the electrolytic plating solution is preferably 10 g / L to 300 g / L, more preferably 100 g / L to 250 g / L, from the viewpoint of plating speed. The concentration of sulfuric acid in the electrolytic plating solution is preferably 30 g / L to 400 g / L, more preferably 50 g / L to 200 g / L, from the viewpoint of plating speed.

[0037] Furthermore, in order to form a metal layer having a uniform thickness and a smooth surface, a chloride ion source can be used in the electroplating solution of the present invention. The chloride ion source in the electroplating solution is preferably blended to a concentration of 5 mg / L to 200 mg / L, more preferably 20 mg / L to 150 mg / L. The chloride ion source is not particularly limited, but examples thereof include NaCl and HCl.

[0038] Furthermore, the electroplating solution of the present invention may contain a plating accelerator (brightener) such as an organic compound containing elemental sulfur and its salt compound. Examples of the plating accelerator include compounds represented by the following general formulas (2) to (4).

[0039] XO3S-R-SH (2) XO3S-Ar-S-S-Ar-SO3X (3)

[0040] In the above general formula (2), R is an optionally substituted alkyl group, preferably an alkyl group having 1 to 6 carbon atoms, and more preferably an alkyl group having 1 to 4 carbon atoms. In the above general formula (3), Ar is an optionally substituted aryl group, for example, an optionally substituted phenyl group or naphthyl group. In the above general formulas (2) and (3), X is a counter ion, for example, sodium or potassium.

[0041]

[0042] In the above general formula (4), R 11 and R 12 each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 9 carbon atoms which may have a substituent having 1 to 3 carbon atoms, or an aryl group having 1 to 3 carbon atoms which may have a substituent; M represents an alkali metal, ammonium, or a monovalent organic ammonium; and α represents a number from 1 to 7.

[0043] Among the above plating accelerators, sodium 3,3'-dithiobis(1-propanesulfonate) (hereinafter sometimes referred to as SPS) is preferred because it is highly effective in accelerating the formation of a metal layer.

[0044] From the viewpoint of being able to form a metal layer with a high embedding rate and high thickness uniformity, the concentration of the plating accelerator in the electroplating solution is preferably 1 mg / L to 1000 mg / L, more preferably 5 mg / L to 500 mg / L, and even more preferably 30 mg / L to 300 mg / L.

[0045] Furthermore, it is preferable to incorporate a plating inhibitor into the electroplating solution of the present invention. Examples of plating inhibitors that can be used include oxygen-containing high molecular weight organic compounds, specifically polyethylene glycol, polypropylene glycol, polyoxyethylene-polyoxypropylene random copolymers, and polyoxyethylene-polyoxypropylene block copolymers, with polyethylene glycol being particularly preferred. To enhance the effects of the present invention, these oxygen-containing high molecular weight organic compounds preferably have a molecular weight of 500 to 100,000, more preferably 1,000 to 10,000. Polyethylene glycol with a molecular weight of 1,000 to 10,000 is particularly preferred. From the same perspective, the concentration of the oxygen-containing high molecular weight organic compound in the electroplating solution is preferably 20 mg / L to 5,000 mg / L, more preferably 50 mg / L to 3,000 mg / L.

[0046] The electrolytic plating solution of the present invention may contain any of the other additives known to be suitable for use in plating solutions, provided that they do not impair the effects of the present invention.

[0047] Examples of other additives include anthraquinone derivatives, cationic surfactants, nonionic surfactants, anionic surfactants, amphoteric surfactants, alkanesulfonic acids, alkanesulfonate salts, alkanesulfonate esters, hydroxyalkanesulfonic acids, hydroxyalkanesulfonate salts, hydroxyalkanesulfonate esters, hydroxyalkanesulfonic acid organic acid esters, etc. From the viewpoint of being able to form a metal layer with a high embedment rate and high thickness uniformity, the concentration of other additives in the electroplating solution is preferably 0.1 mg / L to 500 mg / L, more preferably 0.5 mg / L to 100 mg / L.

[0048] <Electrolytic Plating Method> Next, an electrolytic plating method using the electrolytic plating solution of the present invention will be described. The electrolytic plating method of the present invention may be carried out in the same manner as conventional electrolytic plating methods, except that the electrolytic plating solution of the present invention is used as the electrolytic plating solution. Here, an electrolytic copper plating method for forming a copper layer on a substrate will be described.

[0049] The electrolytic plating bath is, for example, a paddle stirring type plating apparatus, and the substrate is immersed in the electrolytic copper plating bath containing the electrolytic copper plating solution of the present invention in a plating tank. The substrate is, for example, a Si substrate with a copper seed layer and a resist pattern formed thereon using a photoresist.

[0050] In this case, the temperature of the electrolytic copper plating bath is, for example, 10°C to 70°C, preferably 20°C to 50°C, from the viewpoint of being able to form a metal layer with a high embedding rate and high uniformity in thickness, and the current density is 1 A / dm 2 ~70 A / dm 2 , preferably 2 A / dm 2 ~50 A / dm 2 , more preferably 5 A / dm 2 ~30 A / dm 2 The electrolytic plating solution can be stirred by air stirring, rapid liquid flow stirring, mechanical stirring using a stirring blade, or the like.

[0051] By filling the openings of the resist pattern with copper under the conditions described above, a copper layer with excellent thickness uniformity can be formed on the substrate.

[0052] Plated products produced using the electrolytic plating method of the present invention are not particularly limited, and examples thereof include a wide range of products such as automotive industry materials (heat sinks, carburetor parts, fuel injectors, cylinders, various valves, engine internals, etc.), electronics industry materials (contacts, circuits, semiconductor packages, printed circuit boards, thin film resistors, capacitors, hard disks, magnetic materials, lead frames, nuts, magnets, resistors, stems, computer parts, electronic components, laser oscillators, optical memory elements, optical fibers, filters, thermistors, heating elements, high-temperature heating elements, varistors, magnetic heads, various sensors (gas, temperature, humidity, light, speed, etc.), MEMS, etc.), precision equipment (copying machine parts, optical equipment parts, watch parts, etc.), aviation and marine materials (hydraulic equipment, screws, engines, turbines, etc.), chemical industry materials (balls, gates, plugs, checks, etc.), various molds, machine tool parts, vacuum equipment parts, etc. The electrolytic plating method of the present invention is preferably used for electronic industrial materials that require particularly fine patterns, and is more preferably used in the manufacture of semiconductor packages and printed circuit boards, such as those typified by TSV formation and bump formation, with semiconductor packages being even more preferred.

[0053] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0054] Synthesis of Additives for Electroplating Solutions Examples 1 to 10 At room temperature, a 10% diethylene glycol aqueous solution (20 g) was mixed with component (a1) and component (a2) in the molar ratios shown in Table 1 in a 200 mL four-neck flask. The amount of component (a2) charged was 1.6 g, and the amount of component (a1) charged was adjusted in accordance with the molar ratio shown in Table 1. The mixture was then stirred under an argon atmosphere, heated to 95°C using an oil bath, and stirred while maintaining that temperature. Heating was stopped after 3 hours, and the mixture was stirred at room temperature for 12 hours. 1 The completion of the reaction was confirmed by H-NMR, and the mixture was filtered through a PTFE filter. The solvent was then removed under slightly reduced pressure using an oil bath to obtain the electroplating solution additives of Examples 1 to 10.

[0055]

[0056] Comparative Examples 1 to 9 At room temperature, a 10% diethylene glycol aqueous solution (20 g) was mixed with an epoxy compound and an amine compound in the molar ratios shown in Table 2 in a 200 mL four-neck flask. The amount of the amine compound charged was 1.6 g, and the amount of the epoxy compound charged was adjusted in accordance with the molar ratios shown in Table 2. The mixture was then stirred under an argon atmosphere, heated to 95°C using an oil bath, and stirred while maintaining that temperature. Heating was stopped after 3 hours, and the mixture was stirred at room temperature for 12 hours. 1 The completion of the reaction was confirmed by H-NMR, and the mixture was filtered through a PTFE filter. The solvent was then removed under slightly reduced pressure using an oil bath to obtain the electroplating solution additives of Comparative Examples 1 to 9.

[0057]

[0058] <Preparation of Electrolytic Plating Solution> [Examples 11 to 22] Electrolytic plating solution additives were mixed into a solution containing 160 g / L of copper sulfate pentahydrate, 140 g / L of sulfuric acid, 50 mg / L of hydrogen chloride, and 100 mg / L of SPS to give concentrations shown in Table 3, thereby preparing the electrolytic plating baths of Examples 11 to 22.

[0059]

[0060] Comparative Examples 10 to 18 Electroplating baths for Comparative Examples 10 to 18 were prepared by mixing additives for electroplating solutions to concentrations shown in Table 4 into a solution containing 160 g / L of copper sulfate pentahydrate, 140 g / L of sulfuric acid, 50 mg / L of hydrogen chloride, and 100 mg / L of SPS.

[0061]

[0062] <Formation of Metal Layer (Copper Layer) by Electroplating> [Examples 23 to 34 and Comparative Examples 19 to 27] A copper-seeded silicon wafer in which a via hole with a diameter of 20 μm and a height of 10 μm was formed was plated with the electroplating baths of Examples 11 to 22 and the electroplating baths of Comparative Examples 10 to 18 at a cathode current density of 3 A / dm 2Electrolytic copper plating was performed under the following conditions: 1000 kJ / cm2, bath temperature 25°C, plating time 10 minutes. The cross-sections of the vias on the resulting silicon wafers were observed with a scanning electron microscope to evaluate the via embedment ratio. The embedment ratio is the embedment ratio of the copper-plated surface from the bottom of the via, with the copper-plated surface in the via-free area taken as the standard. Next, under the same plating conditions, electrolytic plating was performed on a resist pattern wafer containing a mixture of 30 μm and 75 μm hole diameters. After the resist was stripped, the plating thickness of the resulting plated pattern was observed with a laser microscope (Keyence Corporation, model number: VK-9700). As shown in FIG. 1 , the difference 6 (ΔH) between the height 4 (H1) of the first metal layer 1 and the height 5 (H2) of the second metal layer 2 formed on the surface of the substrate 3 was measured to evaluate thickness uniformity. The results are shown in Tables 5 and 6.

[0063]

[0064]

[0065] The results in Tables 5 and 6 show that when a metal layer is formed by the electrolytic plating method using the electrolytic plating baths of Examples 11 to 22, a metal layer with a higher embedment ratio can be formed than when the electrolytic plating baths of Comparative Examples 10 to 18 are used.

[0066] In Tables 5 and 6, the smaller the ΔH value, the more excellent the thickness uniformity of the metal layer formed. The results in Tables 5 and 6 show that when a metal layer was formed by the electrolytic plating method using the electrolytic plating baths of Examples 11 to 22, the ΔH values ​​were smaller than when the electrolytic plating baths of Comparative Examples 10 to 18 were used, and therefore it was found that a metal layer with excellent thickness uniformity could be formed. In particular, when a metal layer was formed by the electrolytic plating method using the electrolytic plating baths of Examples 11, 12, 15, 16, and 20, it was found that a metal layer with even more excellent thickness uniformity could be formed. In particular, it was found that when a metal layer was formed by the electrolytic plating method using the electrolytic plating bath of Example 11, a metal layer with particularly excellent thickness uniformity could be formed.

[0067] As explained above, it was found that when a metal layer is formed on a substrate to be plated by an electroplating method using an electroplating solution containing the electroplating bath additive of the present invention, a metal layer with a high embedment rate and a highly uniform thickness can be formed. In particular, it was confirmed that when an electroplating bath containing the electroplating bath additive of Example 1 is used, a metal layer with a high embedment rate and a particularly high uniformity of thickness can be formed.

[0068] 1 First metal layer (width 30 μm) 2 Second metal layer (width 75 μm) 3 Base 4 Height of first metal layer (H1) 5 Height of second metal layer (H2) 6 Difference in height between first metal layer 1 and second metal layer 2 (ΔH)

Claims

1. An additive for an electrolytic plating solution containing a reaction product of at least one epoxy compound (a1) represented by the following general formula (1) and at least one tertiary amine compound (a2). (In the formula, m 1 ~m 3 each independently represents an integer of 1 to 5, and * represents a bond.) 2. The additive for electrolytic plating solution according to claim 1, wherein the epoxy compound (a1) is triglycidyl isocyanurate.

3. The additive for electrolytic plating solution according to claim 1 or 2, wherein the tertiary amine compound (a2) is an azole compound.

4. The additive for electrolytic plating solution according to claim 3, wherein the azole compound is selected from the group consisting of imidazole, pyrazole, isothiazole, isoxazole, 1,2,3-triazole, 1,2,4-triazole, and benzimidazole.

5. The additive for electrolytic plating solution according to any one of claims 1 to 4, wherein the molar ratio of the epoxy compound (a1) to the total of the epoxy compound (a1) and the tertiary amine compound (a2) is 0.05 to 0.

95.

6. An electrolytic plating solution containing the additive for electrolytic plating solution according to any one of claims 1 to 5.

7. An electrolytic plating method using the electrolytic plating solution according to claim 6.

8. A method for manufacturing a metal layer using the electrolytic plating method according to claim 7.