Aqueous composition, etching method using same, and method for manufacturing semiconductor substrate

Abstract

The present invention relates to an aqueous etching composition suitable for use in forming wiring on a semiconductor substrate having a copper-containing seed layer and an iron alloy-containing layer. The aqueous composition of the present invention is an aqueous composition for etching the copper-containing seed layer and the iron alloy-containing layer in forming wiring on a semiconductor substrate, and is characterized by comprising (A) hydrogen peroxide and (B) an organic acid, with a mass ratio (A) / (B) of (A) hydrogen peroxide to (B) organic acid in the range of 0.04 to 20, and a pH value of 0.5 to 5.0.

Description

[Technical Field]

[0001] The present invention relates to an aqueous composition capable of selectively etching a copper-containing seed layer in forming wiring on a semiconductor substrate having the copper-containing seed layer and an iron-alloy-containing layer, and also to an etching method and a method for manufacturing a semiconductor substrate using the aqueous composition. [Background technology]

[0002] In the formation of wiring on a semiconductor substrate, etching solutions for etching layers containing copper or copper alloys are known (for example, Patent Documents 1 to 3). In addition, in the formation of wiring on a semiconductor substrate, bumps containing nickel are generally used, but in recent years, bumps containing nickel and iron alloys have been attracting attention (for example, Non-Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2011 / 074589 [Patent Document 2] International Publication No. 2017 / 188108 [Patent Document 3] International Publication No. 2020 / 105605 [Non-patent literature]

[0004] [Non-Patent Document 1] J.-K. Koo and J.-H. Lee, Materials Transactions, Vol. 58, No.2 (2017) pp. 148-151 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventionally, no aqueous etching composition is known that can selectively etch copper or copper alloys while suppressing etching of iron alloys. It is desired to provide an aqueous etching composition that is suitable for use in forming wiring on a semiconductor substrate having a copper-containing seed layer and an iron alloy-containing layer. [Means for solving the problem]

[0006] The present inventors provide the following aqueous composition, an etching method using the same, and a method for producing a semiconductor substrate.

[0007] [1] An aqueous composition for etching a copper-containing seed layer in forming wiring on a semiconductor substrate having the copper-containing seed layer and a layer containing an iron alloy, comprising: (A) hydrogen peroxide and (B) organic acid, and the mass ratio (A) / (B) of (A) hydrogen peroxide to (B) organic acid is in the range of 0.04 to 20; An aqueous composition having a pH value of 0.5 to 5.0. [2] The aqueous composition according to [1], comprising, based on the total amount of the aqueous composition, (A) 0.5 to 30 mass % of hydrogen peroxide and (B) 1 to 50 mass % of an organic acid. [3] The aqueous composition according to [1] or [2] above, wherein the mass ratio (A) / (B) of (A) hydrogen peroxide to (B) organic acid is in the range of 0.04 to 10. [4] The aqueous composition according to any one of [1] to [3], wherein the contents of (A) hydrogen peroxide, (B) organic acid, and (C) water are 95 mass% or more based on the total amount of the aqueous composition. [5] The aqueous composition according to any one of the above [1] to [4], which contains a corrosion inhibitor selected from the group consisting of (i) a nitrogen-containing heterocyclic compound and (ii) a cationic surfactant. [6] An etching method for forming wiring on a semiconductor substrate having a copper-containing seed layer and an iron alloy-containing layer, the method comprising the step of etching the copper-containing seed layer using the aqueous composition according to any one of [1] to [5]. [7] A method for manufacturing a semiconductor substrate, in forming wiring on a semiconductor substrate having a copper-containing seed layer and an iron alloy-containing layer, comprising a step of etching the copper-containing seed layer using the aqueous composition described in any one of [1] to [5] above. [8] A kit for use in the etching method described in [6] above, comprising (a) a first solution containing hydrogen peroxide and (b) a second solution containing an organic acid, which are not mixed with each other, and in which the first solution and the second solution are mixed together at the time of use to prepare the aqueous composition. [9] A kit for use in the method for manufacturing a semiconductor substrate according to [7] above, comprising (a) a first solution containing hydrogen peroxide and (b) a second solution containing an organic acid, which are not mixed with each other, and in which the first solution and the second solution are mixed together at the time of use to prepare the aqueous composition. [Effects of the Invention]

[0008] According to the present invention, there is provided an aqueous composition for etching a copper-containing seed layer, which is suitably used for forming wiring on a semiconductor substrate having a copper-containing seed layer and a layer containing an iron alloy. Furthermore, according to the present invention, there are provided an etching method and a method for manufacturing a semiconductor substrate using the aqueous composition. Conventionally, in forming wiring on a semiconductor substrate, the copper-containing seed layer may be excessively etched, mainly at its edges, resulting in undercutting. However, preferred embodiments of the present invention are also excellent in suppressing undercutting. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing an example of a side surface of a semiconductor substrate before etching (a stacked body having a layer containing an iron alloy). [Figure 2] FIG. 1 is a schematic diagram showing the side surface of a semiconductor substrate (a laminate not having a layer containing an iron alloy) before etching treatment used in evaluations in Examples and Comparative Examples. [Figure 3] 3 is an enlarged schematic view showing a part of the semiconductor substrate of FIG. 2. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] The aqueous composition of the present invention will be specifically described below, but the present invention is not limited thereto and various modifications are possible within the scope of the present invention.

[0011] <1.Aqueous composition> The aqueous composition of the present invention contains at least (A) hydrogen peroxide and (B) organic acid, with the mass ratio (A) / (B) of (A) hydrogen peroxide to (B) organic acid being in the range of 0.04 to 20, and the pH value being 0.5 to 5.0. The aqueous composition of the present invention preferably contains 0.5 to 30 mass% of (A) hydrogen peroxide and 1 to 50 mass% of (B) organic acid, based on the total mass of the aqueous composition.

[0012] According to a preferred embodiment of the present invention, when the aqueous composition of the present invention contains one or more iron alloys as wiring materials, it is capable of selectively etching copper or copper alloys while suppressing dissolution of these metals. According to another preferred embodiment of the present invention, when the aqueous composition contains one or more iron alloys, one or more nickel and nickel alloys, and one or more tin, tin alloys, gold, and gold alloys, it is capable of selectively etching copper and copper alloys while suppressing dissolution of these metals. In this specification, the term "copper alloy" is not particularly limited as long as it is obtained by adding one or more metallic or non-metallic elements to copper and has metallic properties. Similarly, the term "iron alloy" is not particularly limited as long as it is obtained by adding one or more metallic or non-metallic elements to iron and has metallic properties. The same applies to "nickel alloy," "tin alloy," and "gold alloy." In this specification, the copper concentration of the copper alloy is preferably 50 to 99.99 mass%, more preferably 60 to 99.99 mass%, even more preferably 70 to 99.99 mass%, and particularly preferably 80 to 99.99 mass%. Metal atoms other than copper contained in the copper alloy include zinc, tin, lead, aluminum, and nickel. Examples of copper alloys that are preferably used include brass, bronze, cupronickel, nickel silver, and beryllium copper. The iron concentration of the iron alloy is preferably 20 to 90 mass%, more preferably 20 to 80 mass%, even more preferably 30 to 60 mass%, and particularly preferably 35 to 65 mass%, or 40 to 60 mass%. Nickel, cobalt, etc. are preferably used as metal atoms other than iron contained in the iron alloy. Examples of preferred iron alloys include nickel-iron alloys (NiFe) and cobalt-iron alloys (CoFe). In this specification, a "nickel alloy" is an alloy that does not fall under the category of an iron alloy and contains nickel as a main component. The same applies to a "tin alloy" and a "gold alloy."

[0013] Preferred examples of materials to be etched with the aqueous composition of the present invention include laminates of a copper-containing seed layer and a layer containing an iron alloy; laminates of a copper-containing seed layer, a layer containing an iron alloy, and a layer containing nickel or a nickel alloy; and laminates of a copper-containing seed layer, a layer containing an iron alloy, a layer containing nickel or a nickel alloy, and a layer containing tin, a tin alloy, gold, or a gold alloy.

[0014] In this specification, the term "copper-containing seed layer" refers to a metal layer containing copper or a copper alloy, which serves as a base layer for forming wiring on a semiconductor substrate. The copper-containing seed layer is preferably formed by sputtering, electroless plating, or the like. The "iron alloy-containing layer" is formed on the seed layer and is used as a wiring material for a semiconductor substrate, for example, as one of the metal layers constituting a bump of the semiconductor substrate. The iron alloy-containing layer is preferably formed by electrolytic plating or the like. The "layer containing nickel or a nickel alloy," the "layer containing tin or a tin alloy," and the "layer containing gold or a gold alloy" are also formed on the seed layer and, together with the layer containing an iron alloy, are used as wiring materials for a semiconductor substrate, for example, as one of the metal layers constituting a bump on a semiconductor substrate. These layers are preferably formed by electrolytic plating or the like.

[0015] An example of an etching target using the aqueous composition of the present invention is a semiconductor substrate 10 having the structure shown in Fig. 1. The semiconductor substrate 10 is a semiconductor substrate before etching, and includes an upper tin-silver alloy (SnAg) layer 14, a nickel-iron alloy (NiFe) layer 15 laminated below the SnAg layer 14, a nickel (Ni) layer 16 laminated below the NiFe layer 15, and a copper (Cu) layer 12 as a seed layer laminated below the Ni layer 16. Furthermore, as shown in Fig. 1, the semiconductor substrate 10 may have a titanium (Ti) layer 18 laminated below the Cu layer 12 as a barrier metal layer, with the Ti layer 18 being provided on a substrate 20.

[0016] Each component contained in the aqueous composition of the present invention will be described in detail below.

[0017] (A) Hydrogen peroxide In the aqueous composition of the present invention, hydrogen peroxide acts primarily as an oxidizing agent that oxidizes copper. The hydrogen peroxide contained in the aqueous composition is usually used as an aqueous solution of appropriate concentration, mixed with other components. The concentration of hydrogen peroxide in the aqueous hydrogen peroxide solution is not particularly limited and may be, for example, 10 to 90%, and is preferably 35 to 60%, which is in line with industrial standards. Hydrogen peroxide may contain up to about 0.01% by mass of a stabilizer, and acceptable stabilizers include sulfuric acid, phosphoric acid, etc. There are no limitations on the manufacturing process or source of hydrogen peroxide, and for example, hydrogen peroxide manufactured by the anthraquinone method can be used.

[0018] The content of hydrogen peroxide is preferably 0.5 to 30 mass%, more preferably 1.0 to 27 mass%, even more preferably 1.5 to 25 mass%, and particularly preferably 2.0 to 22 mass%, 2.5 to 20 mass%, or 3.0 to 20 mass%, based on the total amount of the aqueous composition. The lower limit of the hydrogen peroxide content may be, for example, 0.5 mass%, 1.0 mass%, 1.5 mass%, 2.0 mass%, 2.5 mass%, 3.0 mass%, etc., based on the total amount of the aqueous composition, and the upper limit may be, for example, 30 mass%, 25 mass%, 20 mass%, 15 mass%, 10 mass%, 5 mass%, etc., based on the total amount of the aqueous composition. The range of the hydrogen peroxide content can be selected from a range that combines the above-mentioned lower limit and upper limit. When the content of hydrogen peroxide is within the above range, a good etching rate for the copper-containing seed layer can be achieved, and unnecessary dissolution of the wiring material can be suppressed.

[0019] (B)Organic acid In the aqueous compositions of the present invention, the organic acid acts primarily as an etchant for copper oxidized by hydrogen peroxide. The organic acid is not particularly limited as long as it is an organic compound having a carboxyl group. Examples of the organic acid include aliphatic carboxylic acids, aromatic carboxylic acids, and amino acids. Among them, aliphatic carboxylic acids and aromatic carboxylic acids are preferred, and one or more selected from the group consisting of aliphatic carboxylic acids having 1 to 12 carbon atoms and aromatic carboxylic acids having 6 to 16 carbon atoms are more preferred.

[0020] Examples of aliphatic carboxylic acids include formic acid, acetic acid, propionic acid, lactic acid, glycolic acid, diglycolic acid, pyruvic acid, oxaloacetic acid, oxalic acid, malonic acid, butyric acid, hydroxybutyric acid, tartaric acid, succinic acid, malic acid, maleic acid, fumaric acid, valeric acid, glutaric acid, itaconic acid, adipic acid, caproic acid, citric acid, propanetricarboxylic acid, trans-aconitic acid, enanthic acid, caprylic acid, nonanoic acid, capric acid, lauric acid, myristic acid, palmitic acid, sorbic acid, iminodiacetic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraaminehexaacetic acid, and diaminocyclohexanetetraacetic acid. These can be used alone or in combination of two or more.

[0021] Examples of aromatic carboxylic acids include benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, mandelic acid, 2-methylbenzoic acid, 3-methylbenzoic acid, 4-methylbenzoic acid, 2-ethylbenzoic acid, 3-ethylbenzoic acid, 4-ethylbenzoic acid, salicylic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2-chlorobenzoic acid, 3-chlorobenzoic acid, 4-chlorobenzoic acid, 2-fluorobenzoic acid, 3-fluorobenzoic acid, 4-fluorobenzoic acid, 2-cyanobenzoic acid, 3-cyanobenzoic acid, and 4-cyanobenzoic acid. Nitrobenzoic acid, 2-nitrobenzoic acid, 3-nitrobenzoic acid, 4-nitrobenzoic acid, 2,3-dimethylbenzoic acid, 3,4-dimethylbenzoic acid, 3,5-dimethylbenzoic acid, 2,5-dimethylbenzoic acid, 2,6-dimethylbenzoic acid, 2-hydroxy-3-methylbenzoic acid, 2-hydroxy-4-methylbenzoic acid, 2-hydroxy-5-methylbenzoic acid, 2-hydroxy-6-methylbenzoic acid, 3-hydroxy-2-methylbenzoic acid, 3-hydroxy-4-methylbenzoic acid, 3-hydroxy-5-methylbenzoic acid Acid, 3-hydroxy-6-methylbenzoic acid, 4-hydroxy-2-methylbenzoic acid, 4-hydroxy-3-methylbenzoic acid, 2-methoxybenzoic acid, 3-methoxybenzoic acid, 4-methoxybenzoic acid, 2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 3,6-dihydroxybenzoic acid, 2,4,5-trimethylbenzoic acid, 2,4,6-trimethylbenzoic acid Examples of suitable hydroxycarboxylic acids include 1-naphthalenecarboxylic acid, 2-naphthalenecarboxylic acid, 1-hydroxy-2-naphthalenecarboxylic acid, 6-hydroxy-1-naphthalenecarboxylic acid, 6-hydroxy-2-naphthalenecarboxylic acid, 2-hydroxy-1-naphthalenecarboxylic acid, 3-hydroxy-2-naphthalenecarboxylic acid, 1,4-dihydroxy-2-naphthalenecarboxylic acid, 1-anthracenecarboxylic acid, 2-anthracenecarboxylic acid, 9-anthracenecarboxylic acid, gallic acid, mellitic acid, and cinnamic acid. These can be used alone or in combination of two or more.

[0022] As the organic acid, either an aliphatic carboxylic acid or an aromatic carboxylic acid may be used alone, or both an aliphatic carboxylic acid and an aromatic carboxylic acid may be used. Among these, the organic acid is preferably an aliphatic carboxylic acid, more preferably citric acid, lactic acid, malonic acid, or a combination of two or more of these, and even more preferably citric acid, lactic acid, or a combination of these.

[0023] The content of the organic acid is preferably 1 to 50 mass%, more preferably 3 to 45 mass%, even more preferably 5 to 40 mass%, and particularly preferably 7 to 35 mass%, 8 to 32 mass%, or 10 to 30 mass%, based on the total amount of the aqueous composition. The lower limit of the organic acid content may be, for example, 1.0 mass%, 2.0 mass%, 3.0 mass%, 4.0 mass%, 5.0 mass%, 6.0 mass%, 7.0 mass%, 8.0 mass%, 9.0 mass%, 10.0 mass%, etc., based on the total amount of the aqueous composition, and the upper limit may be, for example, 50 mass%, 45 mass%, 40 mass%, 35 mass%, 30 mass%, 25 mass%, 20 mass%, or 15 mass%, based on the total amount of the aqueous composition. The range of the organic acid content can be selected from a range that combines the above-mentioned lower and upper limits. When the content of the organic acid is within the above range, a good etching rate for the copper-containing seed layer can be achieved, and unnecessary dissolution of the wiring material can be suppressed.

[0024] In the aqueous composition of the present invention, the mass ratio (A) / (B) of (A) hydrogen peroxide to (B) organic acid is 0.04 to 20, preferably 0.04 to 10, more preferably 0.04 to 8, even more preferably 0.04 to 6, and particularly preferably 0.06 to 4. The lower limit of the mass ratio (A) / (B) may be, for example, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, or 0.1, and the upper limit may be, for example, 20, 15, 14, 13, 12, 11, 10, 10.0, 9, 9.0, 8, 8.0, 7, 7.0, 6, 6.0, 5, 5.0, 4, 4.0, 3, 3.0, 2, 2.0, 1, 1.0, etc. The range of the hydrogen peroxide content can be selected from a range that combines the above-mentioned lower and upper limits. When the mass ratio (A) / (B) is within the above range, it is possible to selectively etch the copper-containing seed layer while suppressing etching of the iron alloy.

[0025] (C)Water The water contained in the aqueous composition of the present invention is preferably water from which metal ions, organic impurities, particles, etc. have been removed by distillation, ion exchange treatment, filtration, various adsorption treatments, etc., and pure water is more preferred, with ultrapure water being particularly preferred. The water content in the aqueous composition is adjusted appropriately depending on the contents of other components in the aqueous composition, and is not particularly limited, but is, for example, 40 to 98 mass %, preferably 50 to 95 mass %, and more preferably 60 to 90 mass % based on the total amount of the aqueous composition.

[0026] In the aqueous composition of the present invention, the total content of (A) hydrogen peroxide, (B) organic acid, and (C) water is preferably 95 mass% or more, more preferably 96 mass% or more, even more preferably 97 mass% or more, and particularly preferably 98 mass% or more, 99 mass% or more, or 99.5 mass% or more, based on the total amount of the aqueous composition.

[0027] (D) Corrosion inhibitors The aqueous composition of the present invention may further contain a corrosion inhibitor as needed. In the aqueous composition, the corrosion inhibitor can form a corrosion-resistant layer on the surface of metals such as copper, copper alloys, iron alloys, or nickel by reacting with or adsorbing to the surface. This may effectively suppress corrosion, particularly galvanic corrosion, of layers containing metals with a higher ionization tendency than copper, such as iron alloys or nickel. The corrosion inhibitor also has the effect of suppressing undercutting, which is excessive etching of a copper-containing seed layer. Suitable corrosion inhibitors include, for example, (i) nitrogen-containing heterocyclic compounds and (ii) cationic surfactants. These may be used alone or in combination.

[0028] The total content of the corrosion inhibitors is preferably 0.00001 to 5.0 mass%, more preferably 0.0001 to 3.0 mass%, even more preferably 0.0005 to 1.0 mass%, and particularly preferably 0.001 to 0.5 mass%, based on the total amount of the aqueous composition. An aqueous composition with the corrosion inhibitor content adjusted within the above range can suppress undercutting, which is excessive etching of the copper-containing layer.

[0029] (i) Nitrogen-containing heterocyclic compound The nitrogen-containing heterocyclic compound preferably contains at least a nitrogen-containing five-membered ring compound. The nitrogen-containing five-membered ring compound may have one or more substituents selected from the group consisting of alkyl groups having 1 to 6 carbon atoms, amino groups, and substituted amino groups having one or more substituents selected from the group consisting of alkyl groups having 1 to 6 carbon atoms and phenyl groups. The nitrogen-containing heterocyclic compound may also contain a ring other than the nitrogen-containing five-membered ring, such as an aliphatic ring having 5 to 30 carbon atoms or an aromatic ring having 6 to 30 carbon atoms, or these rings may be fused with the nitrogen-containing five-membered ring. The nitrogen-containing five-membered ring compound is, for example, one or more selected from the group consisting of pyrrole, pyrazole, imidazole, triazole, and tetrazole. The nitrogen-containing five-membered ring compound may be a single compound or a combination of two or more compounds.

[0030] The nitrogen-containing five-membered ring compound is preferably a compound represented by the following formula (1), formula (2), or formula (3): [ka] [In formulas (1) to (3), R 1 , R 2 , R 3 , R 4 and R 5 are each independently selected from the group consisting of (a) a hydrogen atom, (b) an alkyl group having 1 to 6 carbon atoms, (c) an amino group, and (d) a substituted amino group having one or more substituents selected from the group consisting of an alkyl group having 1 to 6 carbon atoms and a phenyl group, or R 2 and R 3 may be bonded to each other to form an aliphatic ring having 5 to 30 carbon atoms or an aromatic ring having 6 to 30 carbon atoms, R 4 and R 5 may be bonded to each other to form an aliphatic ring having 5 to 30 carbon atoms or an aromatic ring having 6 to 30 carbon atoms.] Examples of the compound include compounds represented by the following formula: The aliphatic ring preferably has 6 to 24 carbon atoms, more preferably 6 to 16 or 8 to 12 carbon atoms, and the aromatic ring preferably has 6 to 24 carbon atoms, more preferably 6 to 16 or 8 to 12 carbon atoms.

[0031] Examples of the alkyl group having 1 to 6 carbon atoms include a linear or branched alkyl group and a cycloalkyl group. Examples of the linear or branched alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, and an n-hexyl group. Examples of the cycloalkyl group include a cycloalkyl group having 3 to 6 carbon atoms, such as a cyclopropyl group, a cyclopentyl group, and a cyclohexyl group. Among these, a methyl group or an ethyl group is preferred, and a methyl group is particularly preferred.

[0032] The substituted amino group is not particularly limited as long as it has one or more substituents selected from the group consisting of alkyl groups having 1 to 6 carbon atoms and phenyl groups. The alkyl groups having 1 to 6 carbon atoms are as described above.

[0033] Preferred specific examples of the nitrogen-containing five-membered ring compound include 5-methyltetrazole, 5-aminotetrazole, 1,2,4-triazole, 3-amino-1,2,4-triazole, 1,2,3-triazole, tetrazole, and benzotriazole (1,2,3-benzotriazole). Among these, one or more selected from the group consisting of 1,2,4-triazole, 3-amino-1,2,4-triazole, 5-methyltetrazole, 5-aminotetrazole, and 1,2,3-benzotriazole are particularly preferred. In addition to those represented by the above formulas (1) to (3), pyrrole, pyrazole, and compounds having the above R 1 ~R 5 Preferably, the alkyl group contains a substituent represented by the following formula:

[0034] In addition, examples of nitrogen-containing heterocyclic compounds include those other than nitrogen-containing five-membered ring compounds, such as nitrogen-containing six-membered ring compounds, such as pyridine, pyrazine, pyrimidine, pyridazine, triazine, tetrazine, pentazidine, and hexazine, and compounds having the above-mentioned R 1 ~R 5 Preferably, the alkyl group contains a substituent represented by the following formula: The nitrogen-containing heterocyclic compound may be used alone or in combination of two or more kinds.

[0035] The content of the nitrogen-containing heterocyclic compound in the aqueous composition is, for example, 0.0001 to 5.0 mass%, preferably 0.01 to 5.0 mass%, more preferably 0.05 to 2.0 mass%, even more preferably 0.07 to 1.0 mass%, and particularly preferably 0.1 to 0.5 mass%, based on the total amount of the aqueous composition.

[0036] (ii) Cationic surfactants The cationic surfactant preferably includes an alkyl group-containing quaternary ammonium hydroxide or a salt thereof, and an alkyl group-containing heteroaryl hydroxide or a salt thereof. (a) Alkyl-containing quaternary ammonium hydroxide or its salt A preferred example of the alkyl group-containing quaternary ammonium hydroxide or a salt thereof is represented by the following formula (4). [ka]

[0037] In the above formula (4), R 6 is a substituted or unsubstituted alkyl group having 4 to 30 carbon atoms, a substituted or unsubstituted alkyl(poly)heteroalkylene group having 4 to 30 carbon atoms, or a substituted or unsubstituted aryl(poly)heteroalkylene group having 4 to 30 carbon atoms.

[0038] The alkyl group having 4 to 30 carbon atoms is not particularly limited, and examples thereof include a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a dodecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an icosyl group, a docosyl group, a tetracosyl group, a hexacosyl group, an octacosyl group, and a triacontyl group.

[0039] When a substituted or unsubstituted alkyl group having 4 to 30 carbon atoms has a substituent (a substituted alkyl group having 4 to 30 carbon atoms), the substituent is not particularly limited, but examples thereof include halogen atoms such as fluorine, chlorine, bromine, and iodine; aryl groups having 6 to 20 carbon atoms such as a phenyl group and a naphthyl group; alkoxy groups having 1 to 6 carbon atoms such as a methoxy group, an ethoxy group, and a propyloxy group; a hydroxy group; a cyano group; and a nitro group. The number of substituents may be one or more. Furthermore, a substituted alkyl group having 4 to 30 carbon atoms means that the total number of carbon atoms in the substituent and the alkyl group is 4 to 30. In other words, the substituted alkyl group having 4 to 30 carbon atoms may include an alkyl group having 4 or more carbon atoms (for example, an alkyl group having 4 to 13 carbon atoms such as a butyl group, a hexyl group, an octyl group, a decyl group, or a dodecyl group) so that the total number of carbon atoms in the substituents falls within the above-mentioned range.

[0040] The alkyl(poly)heteroalkylene group having 4 to 30 carbon atoms is -(C n H 2n -Z-) m -R 8 In this case, n is independently 1 to 5, preferably 1 to 3, and more preferably 1 to 2. m is independently 1 to 5, and preferably 1 to 2. Z is independently an oxygen atom (O), a sulfur atom (S), or a phosphorus atom (P), and preferably an oxygen atom (O). R 8 is an alkyl group having 1 to 30 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, and an icosyl group.

[0041] When the substituted or unsubstituted alkyl(poly)heteroalkylene group having 4 to 30 carbon atoms has a substituent (substituted alkyl(poly)heteroalkylene group having 4 to 30 carbon atoms), the substituent is not particularly limited, but examples thereof include halogen atoms such as fluorine atom, chlorine atom, bromine atom, and iodine atom; aryl groups having 6 to 20 carbon atoms such as phenyl group and naphthyl group; alkoxy groups having 1 to 6 carbon atoms such as methoxy group, ethoxy group, and propyloxy group; hydroxy group; cyano group; and nitro group. The substituent is usually R 8 and a hydrogen atom of the alkyl(poly)heteroalkylene group is substituted with the hydrogen atom of the substituent. The group may have one or more substituents. Furthermore, a substituted alkyl(poly)heteroalkylene group having 4 to 30 carbon atoms means that the total number of carbon atoms in the substituent and the alkyl(poly)heteroalkylene group is 4 to 30. That is, a substituted alkyl(poly)heteroalkylene group having 4 to 30 carbon atoms can include an alkyl(poly)heteroalkylene group having 4 or more carbon atoms (for example, an alkyl group having 4 to 13 carbon atoms, such as a butyl group, hexyl group, octyl group, decyl group, or dodecyl group) so that the total number of carbon atoms in the substituents falls within the above-mentioned range.

[0042] The aryl(poly)heteroalkylene group having 4 to 30 carbon atoms is -(C n H 2n -Z-) m -Ar. In this case, each n is independently 1 to 5, preferably 1 to 3, and more preferably 1 or 2. m is 1 to 5, and preferably 1 or 2. Each Z is independently an oxygen atom (O), a sulfur atom (S), or a phosphorus atom (P), and preferably an oxygen atom (O). Ar is an aryl group having 6 to 18 carbon atoms, such as a phenyl group, a naphthyl group, or an anthracenyl group.

[0043] When a substituted or unsubstituted aryl(poly)heteroalkylene group having 4 to 30 carbon atoms has a substituent (a substituted aryl(poly)heteroalkylene group having 4 to 30 carbon atoms), the substituent is not particularly limited, but examples thereof include halogen atoms such as fluorine, chlorine, bromine, and iodine; alkyl groups having 1 to 10 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, and 1,1,3,3-tetramethylbutyl; alkoxy groups having 1 to 6 carbon atoms such as methoxy, ethoxy, and propyloxy; hydroxy groups; cyano groups; and nitro groups. The substituents typically replace hydrogen atoms in Ar. The number of substituents may be one or more. Furthermore, a substituted aryl(poly)heteroalkylene group having 4 to 30 carbon atoms means that the total number of carbon atoms in the substituent and the aryl(poly)heteroalkylene group is 4 to 30. That is, a substituted aryl(poly)heteroalkylene group having 4 to 30 carbon atoms can contain an aryl(poly)heteroalkylene group having 4 or more carbon atoms (for example, an aryl(poly)heteroalkylene group having an alkyl group having 4 to 13 carbon atoms, such as a butyl group, a hexyl group, an octyl group, a decyl group, or a dodecyl group) so that the total carbon number of the substituents falls within the above-mentioned range.

[0044] In one embodiment, R 6 is preferably a substituted or unsubstituted alkyl(poly)heteroalkylene group having 4 to 30 carbon atoms or a substituted or unsubstituted aryl(poly)heteroalkylene group having 4 to 30 carbon atoms, more preferably a substituted or unsubstituted aryl(poly)heteroalkylene group having 6 to 20 carbon atoms, even more preferably a substituted or unsubstituted aryl(poly)heteroalkylene group having 8 to 20 carbon atoms, particularly preferably a substituted or unsubstituted aryl(poly)heteroalkylene group having 10 to 18 carbon atoms, and most preferably a p-(1,1,3,3-tetramethylbutyl)phenyldi(oxyethylene) (p-CHC(CH)CHC(CH)-Ph-(O-CH)-) group.

[0045] In another embodiment, R6 is preferably a substituted or unsubstituted alkyl group having 4 to 25 carbon atoms or a substituted or unsubstituted aryl(poly)heteroalkylene group having 4 to 25 carbon atoms, more preferably a substituted or unsubstituted alkyl group having 6 to 20 carbon atoms or a substituted or unsubstituted aryl(poly)heteroalkylene group having 6 to 20 carbon atoms, and is preferably a dodecyl group, a tetradecyl group, a hexadecyl group, an octadecyl group, p-(1,1,3,3-tetramethylbutyl)phenyldi(oxyethylene)(p-CH3C(CH3)2CH2C(C More preferred is a p-(1,1,3,3-tetramethylbutyl)phenyldi(oxyethylene) (p-CHC(CH)CHC(CH)-Ph-(O-CH)-) group, with a hexadecyl group, an octadecyl group, or a p-(1,1,3,3-tetramethylbutyl)phenyldi(oxyethylene) (p-CHC(CH)CHC(CH)-Ph-(O-CH)-) group being particularly preferred, and a p-(1,1,3,3-tetramethylbutyl)phenyldi(oxyethylene) (p-CHC(CH)CHC(CH)-Ph-(O-CH)-) group being most preferred.

[0046] Also, R 7 are each independently a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms.

[0047] Examples of the alkyl group having 1 to 30 carbon atoms include, but are not limited to, 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, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a dodecyl group, a tetradecyl group, a hexadecyl group, an octadecyl group, a nonadecyl group, and an icosyl group.

[0048] When a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms has a substituent (a substituted alkyl group having 1 to 30 carbon atoms), examples of the substituent include halogen atoms such as fluorine atom, chlorine atom, bromine atom, and iodine atom; aryl groups having 6 to 20 carbon atoms such as phenyl group and naphthyl group; alkoxy groups having 1 to 6 carbon atoms such as methoxy group, ethoxy group, and propyloxy group; hydroxy group; cyano group; and nitro group. The number of substituents may be one or two or more. Furthermore, a substituted alkyl group having 1 to 30 carbon atoms means that the total number of carbon atoms of the substituent and the alkyl group is 1 to 30.

[0049] The aryl group having 6 to 30 carbon atoms is not particularly limited, but examples thereof include a phenyl group, a naphthyl group, and a biphenyl group.

[0050] When a substituted or unsubstituted aryl group having 6 to 30 carbon atoms has a substituent (a substituted aryl group having 6 to 30 carbon atoms), examples of the substituent include halogen atoms such as fluorine, chlorine, bromine, and iodine atoms; alkyl groups having 1 to 10 carbon atoms such as methyl, ethyl, propyl, and isopropyl; alkoxy groups having 1 to 6 carbon atoms such as methoxy, ethoxy, and propyloxy; hydroxy groups; cyano groups; and nitro groups. The number of substituents may be one or more. A substituted aryl group having 6 to 30 carbon atoms means that the total number of carbon atoms in the substituent and the alkyl group is 6 to 30.

[0051] Of these, R 7 is preferably a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, more preferably a methyl group, ethyl group, propyl group, isopropyl group, hexyl group, octyl group, decyl group, dodecyl group, tetradecyl group, hexadecyl group, octadecyl group, benzyl group, hydroxymethyl group, or 2-hydroxyethyl group, even more preferably a methyl group, ethyl group, benzyl group, or 2-hydroxyethyl group, particularly preferably a methyl group or a benzyl group, and most preferably a methyl group. 7is preferably an alkyl group having 1 to 10 carbon atoms substituted with an aryl group having 6 to 20 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms substituted with a phenyl group, further preferably a benzyl group or a phenylethyl group, and particularly preferably a benzyl group.

[0052] X is a halide ion (fluoride ion, chloride ion, bromide ion, iodide ion, etc.), hydroxide ion, organic sulfonate ion (methanesulfonate ion, p-toluenesulfonate ion, etc.), tetrafluoroborate anion, or hexafluorophosphate anion. Of these, X is preferably a halide ion, and more preferably a chloride ion or bromide ion.

[0053] R 6Specific examples of the ammonium salt represented by formula (4) in which is a substituted or unsubstituted alkyl group having 4 to 30 carbon atoms include ammonium salts having a butyl group, such as butyltrimethylammonium bromide and benzyldimethylbutylammonium chloride; ammonium salts having a hexyl group, such as hexyltrimethylammonium bromide and benzyldimethylhexylammonium chloride; ammonium salts having an octyl group, such as octyltrimethylammonium bromide and benzyldimethyloctylammonium chloride; ammonium salts having a decyl group, such as decyltrimethylammonium bromide and benzyldimethyldecylammonium chloride; ammonium salts having a dodecyl group, such as dodecyltrimethylammonium bromide and benzyldimethyldodecylammonium chloride; tetradecyltrimethylammonium bromide and benzyldimethyldodecylammonium chloride; ammonium salts having a tetradecyl group, such as benzyldimethyltetradecylammonium chloride; ammonium salts having a hexadecyl group, such as hexadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium p-toluenesulfonate, hexadecyltrimethylammonium hydroxide, ethylhexadecyldimethylammonium chloride, ethylhexadecyldimethylammonium bromide, and benzyldimethylhexadecylammonium chloride; and ammonium salts having an octadecyl group, such as trimethyloctadecylammonium chloride, trimethyloctadecylammonium bromide, dimethyldioctadecylammonium chloride, dimethyldioctadecylammonium bromide, and benzyldimethyloctadecylammonium chloride.

[0054] R 6 Specific examples of the ammonium salt represented by formula (4), in which is a substituted or unsubstituted alkyl(poly)heteroalkylene group having 4 to 30 carbon atoms, include trimethylpropyldi(oxyethylene)ammonium chloride and trimethylpropyloxyethylenethioethyleneammonium chloride.

[0055] R 6Specific examples of the ammonium salt represented by formula (4), in which is a substituted or unsubstituted aryl(poly)heteroalkylene group having 4 to 30 carbon atoms, include benzyldimethyl-2-{2-[4-(1,1,3,3-tetramethylbutyl)phenoxy]ethoxy}ethylammonium chloride (benzethonium chloride) and benzyldimethylphenyldi(oxyethylene)ammonium chloride.

[0056] In one embodiment, the ammonium salt represented by the formula (4) is R 6 is a substituted or unsubstituted aryl (poly) heteroalkylene group having 4 to 30 carbon atoms, and R 7 At least one of R is preferably a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, 6 is a substituted or unsubstituted aryl (poly) heteroalkylene group having 8 to 20 carbon atoms, and R 7 It is more preferable that at least one of R is a substituted or unsubstituted aryl group having 6 to 15 carbon atoms, 6 is a substituted or unsubstituted aryl (poly) heteroalkylene group having 10 to 18 carbon atoms, and R 7 It is more preferable that at least one of the groups is a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, and it is particularly preferable that the group is benzyldimethyl-2-{2-[4-(1,1,3,3-tetramethylbutyl)phenoxy]ethoxy}ethylammonium chloride (benzethonium chloride).

[0057] (b) alkyl group-containing heteroaryl hydroxide or its salt Specific preferred examples of alkyl group-containing heteroaryl hydroxides or salts thereof include heteroaryl hydroxides or salts thereof having a substituted or unsubstituted alkyl group having 4 to 30 carbon atoms. The salt of a heteroaryl having a substituted or unsubstituted alkyl group having 4 to 30 carbon atoms preferably contains a substituted or unsubstituted nitrogen atom-containing heteroaryl ring, and particularly preferred examples include salts of a heteroaryl cation in which at least one nitrogen atom of the substituted or unsubstituted nitrogen atom-containing heteroaryl ring is bonded to a substituted or unsubstituted alkyl group having 4 to 30 carbon atoms.

[0058] The nitrogen atom-containing heteroaryl ring is not particularly limited, but examples thereof include imidazole, pyrazole, oxazole, isoxazole (isoxazole), thiazole, isothiazole, pyridine, pyrazine, pyridazine, pyrimidine, quinoline, and isoquinoline rings.

[0059] When the nitrogen atom-containing heteroaryl ring has a substituent other than a substituted or unsubstituted alkyl group having 4 to 30 carbon atoms, examples of the substituent include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom; an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group, or an isopropyl group; an aryl group having 6 to 20 carbon atoms such as a phenyl group or a naphthyl group; an alkoxy group having 1 to 6 carbon atoms such as a methoxy group, an ethoxy group, or a propyloxy group; a hydroxy group; a cyano group; and a nitro group.

[0060] The alkyl group having 4 to 30 carbon atoms is not particularly limited, and examples thereof include a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a dodecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an icosyl group, a docosyl group, a tetracosyl group, a hexacosyl group, an octacosyl group, and a triacontyl group.

[0061] When a substituted or unsubstituted alkyl group having 4 to 30 carbon atoms has a substituent (a substituted alkyl group having 4 to 30 carbon atoms), examples of the substituent include halogen atoms such as fluorine, chlorine, bromine, and iodine; alkyl groups having 1 to 4 carbon atoms such as methyl, ethyl, propyl, and isopropyl; aryl groups having 6 to 20 carbon atoms such as phenyl and naphthyl; alkoxy groups having 1 to 6 carbon atoms such as methoxy, ethoxy, and propyloxy; hydroxy groups; cyano groups; and nitro groups. The group may have one or more substituents. Furthermore, a substituted alkyl group having 4 to 30 carbon atoms means that the total number of carbon atoms in the substituent and the alkyl group is 4 to 30. In other words, the substituted alkyl group having 4 to 30 carbon atoms may contain an alkyl group having 4 or more carbon atoms (for example, an alkyl group having 4 to 13 carbon atoms such as a butyl group, hexyl group, octyl group, decyl group, and dodecyl group) so that the total number of carbon atoms in the substituent falls within the above-mentioned range.

[0062] Of these, the substituted or unsubstituted alkyl group having 4 to 30 carbon atoms is preferably a substituted or unsubstituted alkyl group having 8 to 20 carbon atoms, more preferably an alkyl group having 12 to 18 carbon atoms, still more preferably a dodecyl group, a tetradecyl group, a hexadecyl group, or an octadecyl group, and from the viewpoint of suppressing undercut of the copper-containing seed layer, a dodecyl group, a tetradecyl group, or a hexadecyl group is particularly preferred.

[0063] The counter anion of a heteroaryl cation having a substituted or unsubstituted alkyl group having 4 to 30 carbon atoms is not particularly limited, and examples thereof include halide ions such as fluoride ion, chloride ion, bromide ion, and iodide ion; hydroxide ion; organic sulfonate ions such as methanesulfonate ion and p-toluenesulfonate ion; tetrafluoroborate anion; and hexafluorophosphate anion. Among these, the counter anion is preferably a halide ion, and more preferably a chloride ion or a bromide ion.

[0064] Specific examples of heteroaryl salts having a substituted or unsubstituted alkyl group having 4 to 30 carbon atoms include 1-butyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium bromide, 1-hexyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium bromide, 1-octyl-3-methylimidazolium chloride, 1-octyl-3-methylimidazolium bromide, 1-decyl-3-methylimidazolium chloride, 1-decyl-3-methylimidazolium bromide, 1-dodecyl-3 imidazolium salts such as 1-methylimidazolium chloride, 1-dodecyl-3-methylimidazolium bromide, 1-tetradecyl-3-methylimidazolium chloride, 1-tetradecyl-3-methylimidazolium bromide, 1-hexadecyl-3-methylimidazolium chloride, 1-hexadecyl-3-methylimidazolium bromide, 1-octadecyl 3-methylimidazolium chloride, and 1-octadecyl 3-methylimidazolium bromide; 3-butyloxazolium chloride, and 3-hexyloxazolium chloride, Oxazolium salts such as 3-octyloxazolium chloride, 3-decyloxazolium chloride, 3-dodecyloxazolium chloride, 3-tetradecyloxazolium chloride, 3-hexadecyloxazolium chloride, and 3-octadecyloxazolium chloride; 3-butylthiazolium chloride, 3-hexylthiazolium chloride, 3-octylthiazolium chloride, 3-decylthiazolium chloride, 3-dodecylthiazolium chloride, 3-tetradecylthiazolium chloride, and 3-hexadecylthiazolium thiazolium salts such as 1-butylpyridinium chloride, 1-hexylpyridinium chloride, 1-octylpyridinium chloride, 1-decylpyridinium chloride, 1-dodecylpyridinium chloride, 1-tetradecylpyridinium chloride, 1-tetradecylpyridinium bromide, 1-hexadecylpyridinium chloride, 1-hexadecylpyridinium bromide, 1-octadecylpyridinium chloride, 1-octadecylpyridinium bromide, and other pyridinium salts;Pyrimidinium salts such as 1-butylpyrimidinium chloride, 1-hexylpyrimidinium chloride, 1-octylpyrimidinium chloride, 1-decylpyrimidinium chloride, 1-dodecylpyrimidinium chloride, 1-tetradecylpyrimidinium chloride, 1-hexadecylpyrimidinium chloride, and 1-octadecylpyrimidinium chloride; butylquinolinium chloride, hexylquinolinium chloride, and octylquinolinium chloride Examples of quinolinium salts include quinolinium chloride, decylquinolinium chloride, dodecylquinolinium chloride, tetradecylquinolinium chloride, hexadecylquinolinium chloride, and octadecylquinolinium chloride; and isoquinolinium salts include decylisoquinolinium chloride, dodecylisoquinolinium chloride, tetradecylisoquinolinium chloride, hexadecylisoquinolinium chloride, and octadecylisoquinolinium chloride. These may also be used as hydrates.

[0065] Among these, (ii) the cationic surfactant is an ammonium salt represented by formula (4) (wherein R 6 is a substituted or unsubstituted alkyl group having 8 to 20 carbon atoms, or a substituted or unsubstituted aryl(poly)heteroalkylene group having 8 to 20 carbon atoms), an imidazolium salt having a substituted or unsubstituted alkyl group having 8 to 20 carbon atoms, or a pyridinium salt having a substituted or unsubstituted alkyl group having 8 to 20 carbon atoms, and an ammonium salt represented by formula (4) (wherein R 6 is a substituted or unsubstituted aryl (poly) heteroalkylene group having 12 to 20 carbon atoms, and R 7 is a substituted or unsubstituted aryl group having 6 to 12 carbon atoms), an imidazolium salt having a substituted or unsubstituted alkyl group having 10 to 18 carbon atoms, or a pyridinium salt having a substituted or unsubstituted alkyl group having 10 to 18 carbon atoms, and an ammonium salt represented by formula (4) (wherein R 6 is a substituted or unsubstituted aryl(poly)heteroalkylene group having 12 to 18 carbon atoms, and R 7is a substituted or unsubstituted aryl group having 6 to 12 carbon atoms), an imidazolium salt having a substituted or unsubstituted alkyl group having 12 to 18 carbon atoms, or a pyridinium salt having a substituted or unsubstituted alkyl group having 12 to 18 carbon atoms, and an ammonium salt represented by formula (4) (wherein R 6 is a substituted or unsubstituted aryl (poly) heteroalkylene group having 12 to 16 carbon atoms, and R 7 Particularly preferred are pyridinium salts having a substituted or unsubstituted alkyl group having 12 to 16 carbon atoms), at least one of which is a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, and most preferred are benzethonium chloride and benzethonium bromide.

[0066] The cationic surfactant (ii) may be used alone or in combination of two or more. That is, in a preferred embodiment, the cationic surfactant (ii) is an ammonium salt represented by formula (4) (wherein R 6 is a substituted or unsubstituted alkyl group having 10 to 20 carbon atoms, or a substituted or unsubstituted aryl (poly) heteroalkylene group having 10 to 20 carbon atoms), an imidazolium salt having a substituted or unsubstituted alkyl group having 10 to 20 carbon atoms, and a pyridinium salt having a substituted or unsubstituted alkyl group having 10 to 20 carbon atoms, and the ammonium salt represented by formula (4) (wherein R 6 is a substituted or unsubstituted aryl(poly)heteroalkylene group having 16 to 20 carbon atoms, and R 7 more preferably, the compound contains at least one selected from the group consisting of an ammonium salt represented by formula (4) (wherein R 6 is a substituted or unsubstituted aryl (poly) heteroalkylene group having 18 to 20 carbon atoms, and R 7and more preferably, the compound contains at least one selected from the group consisting of an ammonium salt represented by formula (4) (wherein R 6 is a substituted or unsubstituted aryl (poly) heteroalkylene group having 18 to 20 carbon atoms, and R 7 It is particularly preferred that the compound contains at least one selected from the group consisting of pyridinium salts having a substituted or unsubstituted alkyl group having 10 to 14 carbon atoms, at least one of which is a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, and most preferably at least one selected from the group consisting of benzethonium chloride and benzethonium bromide.

[0067] (ii) Specific preferred examples of the cationic surfactant include dodecylpyridinium chloride, benzyldimethylhexadecylammonium chloride, benzethonium chloride, 1-hexadecyl-3-methylimidazolium chloride, octyltrimethylammonium chloride, etc. (ii) The cationic surfactant may be used alone or in combination of two or more.

[0068] The content of (ii) the cationic surfactant in the aqueous composition is, for example, 0.00001 to 0.2 mass%, preferably 0.0001 to 0.1 mass%, more preferably 0.0005 to 0.08 mass%, even more preferably 0.0007 to 0.03 mass%, and particularly preferably 0.001 to 0.01 mass%, based on the total amount of the aqueous composition.

[0069] (E) Additives In addition to the above components, the aqueous composition of the present invention may further contain additives such as a hydrogen peroxide stabilizer, an organic solvent, a surfactant other than a cationic surfactant, a chelating agent, an antifoaming agent, an alkali, a silicon-containing compound, etc., within the scope of not impairing the effects of the aqueous composition of the present invention. For example, known hydrogen peroxide stabilizers such as alcohols, urea, phenylurea, organic carboxylic acids, organic phosphonic acids, and organic phosphoric acids may be added as appropriate. Furthermore, known alkalis such as potassium hydroxide, lithium hydroxide, cesium hydroxide, triethylamine, ammonia, tetramethylammonium hydroxide, ethanolamine, and 1-amino-2-propanol may be added as appropriate. These additives may be used alone or in combination of two or more.

[0070] The pH value of the aqueous composition of the present invention is in the range of 0.5 to 5.0, preferably 0.8 to 4.0, more preferably 1.0 to 3.5, even more preferably 1.2 to 3.2, and particularly preferably 1.5 to 3.0, 1.8 to 3.0, 2.0 to 3.0, or 2.5 to 3.0. The pH value of the aqueous composition can be adjusted by adding an alkali. Preferred examples of the alkali are as described above.

[0071] From the viewpoint of suppressing etching of the layer containing an iron alloy and suppressing undercutting of the seed layer containing copper, the aqueous composition of the present invention preferably does not contain an inorganic acid, or if it contains an inorganic acid, the content of the inorganic acid is preferably less than 0.5 mass % based on the total amount of the aqueous composition, and more preferably less than 0.1 mass %.

[0072] The aqueous composition of the present invention is preferably a solution, and preferably does not contain solid particles such as abrasive particles.

[0073] The aqueous composition of the present invention can selectively etch copper or copper alloys while suppressing etching of iron alloys, and therefore can be suitably used as an aqueous composition for etching a copper-containing seed layer in the formation of wiring on a semiconductor substrate having a copper-containing seed layer and an iron alloy-containing layer. According to a preferred embodiment, the aqueous composition of the present invention is also excellent in the effect of suppressing undercut caused by excessive etching of the edge of a copper-containing seed layer, etc. Specifically, in the measurement method described below, the undercut of the copper-containing seed layer can be suppressed to preferably 0.5 μm or less, more preferably 0.4 μm or less, and even more preferably 0.35 μm or less.

[0074] The aqueous composition of the present invention can be prepared by uniformly stirring (A) hydrogen peroxide, (B) an organic acid, and (C) water, and, if necessary, one or more of (D) a corrosion inhibitor and (E) an additive. The method for stirring these components is not particularly limited, and any stirring method commonly used in the preparation of aqueous compositions can be used.

[0075] The aqueous composition of the present invention is suitable for use as an aqueous composition for etching a copper-containing seed layer in the formation of interconnects on a semiconductor substrate having a copper-containing seed layer and an iron alloy-containing layer. The aqueous composition of the present invention is particularly suitable for use in packaging applications such as next-generation DRAMs and NAND flash memories, where an iron alloy is included as an interconnect material for processes using bumps. The aqueous composition of the present invention is capable of selectively etching copper or copper alloys while suppressing dissolution of the iron alloy, thereby enabling selective etching of the copper-containing seed layer in the formation of interconnects on a semiconductor substrate having a copper-containing seed layer and an iron alloy-containing layer. Furthermore, according to a preferred embodiment, the aqueous composition of the present invention is suitable for use in the above applications, where the interconnect material includes, in addition to an iron alloy, one or more metals selected from the group consisting of nickel, nickel alloys, tin, tin alloys (including SnAg, etc.), gold, and gold alloys, or where the barrier metal layer includes titanium and titanium alloys, while suppressing dissolution of these metals.

[0076] <2. Etching method> The etching method of the present invention comprises the step of etching a copper-containing seed layer using the aqueous composition described above in the formation of wiring on a semiconductor substrate having the copper-containing seed layer and a layer containing an iron alloy.

[0077] The temperature at which the aqueous composition is used in the etching step is not particularly limited, but is preferably 10 to 50°C, more preferably 20 to 45°C, and even more preferably 20 to 40°C. If the temperature of the aqueous composition is 10°C or higher, the etching rate is good, resulting in excellent production efficiency. On the other hand, if the temperature of the aqueous composition is 50°C or lower, changes in the liquid composition can be suppressed, and etching conditions can be maintained constant. Increasing the temperature of the aqueous composition increases the etching rate, but the optimal treatment temperature can be determined appropriately, taking into consideration factors such as minimizing changes in the composition of the aqueous composition (decomposition of hydrogen peroxide).

[0078] The etching time is not particularly limited, but is preferably 10 to 150 seconds, more preferably 30 to 120 seconds. The etching time may be appropriately selected depending on various conditions, such as the surface condition of the object to be etched, the concentration of the aqueous composition, the temperature, and the processing method. For example, in the etching of a copper-containing seed layer, the processing time can be set to the moment when the color of the exposed seed layer disappears (just etching time (JET)). If necessary, the processing time may be set longer than JET.

[0079] The method for contacting the aqueous composition with the etching target, a laminate having a copper-containing seed layer and an iron alloy-containing layer (i.e., a semiconductor substrate before etching), is not particularly limited. For example, wet etching methods such as contacting the etching target by dropping (single-wafer spin processing) or spraying the aqueous composition, or immersing the etching target in the aqueous composition, can be used. Either method may be used in the present invention.

[0080] 3. Manufacturing method of semiconductor substrate The method for manufacturing a semiconductor substrate of the present invention includes at least the etching step described above. providing a semiconductor substrate having a seed layer thereon comprising copper; forming a resist pattern having an opening pattern exposing a portion of the seed layer; forming a metal layer A containing one or more metals selected from the group consisting of nickel and nickel alloys, a metal layer B containing one or more metals selected from the group consisting of iron alloys, and a metal layer C containing one or more metals selected from the group consisting of tin, tin alloys, gold, and gold alloys, in this order, on a surface of the seed layer exposed in an opening of the opening pattern of the resist pattern; removing the resist pattern; and the step of contacting the exposed portion of the seed layer, on which metal layer A, metal layer B, and metal layer C are not formed, obtained in the step of removing the resist pattern, with an aqueous composition to etch the exposed portion of the seed layer. An example of an etching target in the etching step is a semiconductor substrate 10 (semiconductor substrate before etching) having the structure shown in Fig. 1. In the method for manufacturing a semiconductor substrate of the present invention, the metal layer only needs to include metal layer B, and metal layer A and metal layer C are optionally provided.

[0081] <4. Kit> According to one aspect of the present invention, there is provided a kit for use in "2. Etching method" above, the kit comprising (a) a first solution containing hydrogen peroxide and (b) a second solution containing an organic acid, in a mutually unmixed state, and wherein the first solution and the second solution are mixed at the time of use to prepare the aqueous composition. According to another aspect of the present invention, there is provided a kit for use in "3. Method for manufacturing a semiconductor substrate," which comprises (a) a first solution containing hydrogen peroxide and (b) a second solution containing an organic acid, in a mutually unmixed state, and in which the first solution and the second solution are mixed at the time of use to prepare the aqueous composition.

[0082] [First solution] The first solution contains hydrogen peroxide and may further contain water, a stabilizer, and the like, as needed.

[0083] The hydrogen peroxide, water, and stabilizer used are those described above.

[0084] In a preferred embodiment, the first solution comprises hydrogen peroxide and water.

[0085] [Second solution] The second solution contains an organic acid, and may further contain water, a corrosion inhibitor, an additive, etc., as needed.

[0086] The organic acid, water, corrosion inhibitor, and additives used are those described above.

[0087] In a preferred embodiment, the second solution comprises an organic acid and water. In another preferred embodiment, the second solution comprises an organic acid, a corrosion inhibitor, and water. In another preferred embodiment, the second solution contains an organic acid, an additive, and water. In another preferred embodiment, the second solution comprises an organic acid, a corrosion inhibitor, an additive, and water.

[0088] According to the kit of the present invention, the first solution containing hydrogen peroxide and the second solution containing an organic acid are kept in a state where they are not mixed with each other, thereby preventing the decomposition reaction between the organic acid and hydrogen peroxide.

[0089] When used, the kit can be used to prepare an aqueous composition by mixing the first solution and the second solution, which can be used in the above-mentioned semiconductor substrate manufacturing method or the above-mentioned etching method, etc. In this case, in order to adjust the composition of the final composition, at least one selected from the group consisting of hydrogen peroxide, an organic acid, a corrosion inhibitor, water, and an additive, preferably water, can be further added together with the first solution and the second solution. [Example]

[0090] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0091] [Example 1] An aqueous composition for etching semiconductor substrates was prepared by adding (A) hydrogen peroxide (H2O2), (B) citric acid, and (C) ammonia to pure water and stirring. The addition rates of hydrogen peroxide, citric acid, and ammonia were 3 mass%, 10 mass%, and 0.4 mass%, respectively, based on the total amount of the aqueous composition. The pH of the aqueous composition was 2.7. The pH of the aqueous composition was measured at 23°C using a benchtop pH meter (F-71) and a pH electrode (9615S-10D) manufactured by Horiba, Ltd.

[0092] [Examples 2 to 11] The components and amounts added were changed as shown in Table 1 to prepare aqueous compositions for etching semiconductor substrates.

[0093] [Comparative Examples 1 to 11] The components and amounts added were changed as shown in Table 2 to prepare aqueous compositions for etching semiconductor substrates.

[0094] [evaluation] The aqueous compositions produced in Examples 1 to 11 and Comparative Examples 1 to 11 were evaluated for copper just etching time (Cu JET), the amount of dissolved iron (Fe) in the aqueous composition after treatment with a nickel-iron alloy (NiFe) foil, and the amount of copper (Cu) undercut.

[0095] [Evaluation sample] In each example and comparative example, a semiconductor substrate 10 (semiconductor substrate before etching) having the structure shown in Fig. 2 was used as an evaluation substrate. The semiconductor substrate 10 includes an upper tin-silver alloy (SnAg) layer 14, a nickel (Ni) layer 16 laminated below the SnAg layer 14, and a copper (Cu) layer 12 laminated below the Ni layer 16. Furthermore, in the semiconductor substrate 10, a titanium (Ti) layer 18 is laminated below the Cu layer 12, and the Ti layer 18 is provided on a substrate 20. Here, the SnAg layer 14 is a layer made of a tin alloy containing 97 mass % of tin (Sn). In each example and comparative example, a semiconductor substrate 10 was used, which was provided with a Cu layer 12 (thickness: 0.2 μm) as a seed layer, a SnAg layer 14 (thickness: 6 μm) as an upper metal layer, a Ni layer 16 (thickness: 3 μm) as a lower metal layer (plating layer), and a Ti layer 18 (thickness: 0.1 μm) as a barrier metal layer, as shown in Fig. 2 and Fig. 3, which is an enlarged view of the area enclosed by the dashed square in Fig. 2. The diameter of the cylindrical bump shown in Fig. 2 was 12.5 μm, and the height was 9 μm.

[0096] [Evaluation of JET in Cu layer etching] The evaluation sample was 1cm x 1cm (immersion treatment area: 1cm 2 ) size. Next, the evaluation sample was immersed in 50 g of each of the aqueous compositions produced in Examples 1 to 11 and Comparative Examples 1 to 11 for a predetermined time at 27° C. while being stirred with a stirrer at 350 rpm. During the immersion treatment, the evaluation sample was held with tweezers and positioned above the stirrer.

[0097] When the evaluation sample was immersed, the time required from the start of immersion (etching process) until the color of the substrate surface visually changed from orange to silver, i.e., the time required until the color of the copper-containing seed layer disappeared, was defined and measured as Cu JET.

[0098] [Amount of dissolved Fe in aqueous composition after NiFe foil treatment] 42 Invar foil (manufactured by Nilaco Corporation, 0.05 × 100 × 300 mm, containing 57% Fe by mass) was placed on a 1 cm × 1 cm (immersion treatment area: 1 cm 2 ) to prepare NiFe foil samples.

[0099] A NiFe foil sample was immersed in 10 g of each of the aqueous compositions produced in Examples 1 to 11 and Comparative Examples 1 to 11 at 27°C for 10 minutes. The aqueous composition after immersion was diluted 10 to 20 times with a 1% by mass aqueous solution of nitric acid to prepare a measurement sample. The Fe concentration in the measurement sample was measured using an Avio200 (PerkinElmer) ICP optical emission spectrometer (ICP-OES). The amount of dissolved Fe is preferably 100 μg / L or less, more preferably 50 μg / L or less, and even more preferably 30 μg / L or less.

[0100] [Cu undercut amount] Evaluation samples were immersed in the aqueous compositions prepared in Examples 1 to 11 and Comparative Examples 1 to 11 at 27°C for twice the time required for Cu JET (100% OE (overetching)) while stirring at 350 rpm with a stirrer. The evaluation samples after the immersion treatment were processed in a Helios G4 UX (Thermo Scientific) FIB (focused ion beam) device so that the bumps changed from circular to semicircular when observed from above. SEM images of the processed evaluation samples were then obtained using the Helios G4 UX (Thermo Scientific). The horizontal distance from the Ni end face to the Cu end face in the SEM image was defined as the Cu undercut amount and measured. The amount of Cu undercut is preferably 0.5 μm or less, more preferably 0.4 μm or less, and even more preferably 0.35 μm or less.

[0101] [Table 1] [Table 2]

[0102] As shown in Table 1, it was confirmed that the copper-containing seed layer was selectively etched while suppressing corrosion of the iron alloy when the aqueous compositions of Examples 1 to 11 were used. It was also confirmed that the amount of undercut in the Cu layer 12 was suppressed when the aqueous compositions of Examples 1 to 11 were used. On the other hand, when the mass ratio of hydrogen peroxide to organic acid exceeded the range specified in the present invention, etching copper took too long, making it unsuitable for etching a copper-containing seed layer (Comparative Examples 4 and 5).Furthermore, when the pH range exceeded the range specified in the present invention, the amount of undercut in the Cu layer 12 increased (Comparative Example 6). Furthermore, when inorganic acids such as phosphoric acid, sulfuric acid, nitric acid, and hydrochloric acid were used as the acid instead of organic acids, the amount of undercut in the Cu layer 12 increased (Comparative Examples 1 to 3 and 7 to 9). [Explanation of symbols]

[0103] 10. Semiconductor substrate 12 Cu layer (seed layer) 14 SnAg layer (upper metal layer) 15 NiFe layer (intermediate metal layer) 16 Ni layer (lower metal layer) 18 Ti layer (barrier metal layer) 20 PCB

Claims

1. 1. An aqueous composition for etching a copper-containing seed layer in forming wiring on a semiconductor substrate having the copper-containing seed layer and a layer containing an iron alloy, comprising: containing (A) hydrogen peroxide and (B) an organic acid, wherein the mass ratio (A) / (B) of the (A) hydrogen peroxide to the (B) organic acid is in the range of 0.04 to 20; An aqueous composition having a pH value of 0.5 to 5.

0.

2. 2. The aqueous composition according to claim 1, comprising, based on the total amount of the aqueous composition, 0.5 to 30% by mass of (A) hydrogen peroxide and 1 to 50% by mass of (B) an organic acid.

3. 2. The aqueous composition according to claim 1, wherein the mass ratio (A) / (B) of (A) hydrogen peroxide to (B) organic acid is in the range of 0.04 to 10.

4. 2. The aqueous composition according to claim 1, wherein the contents of (A) hydrogen peroxide, (B) organic acid, and (C) water are 95 mass% or more based on the total amount of the aqueous composition.

5. 10. The aqueous composition of claim 1, comprising a corrosion inhibitor selected from the group consisting of (i) a nitrogen-containing heterocyclic compound, and (ii) a cationic surfactant.

6. 6. An etching method for forming wiring on a semiconductor substrate having a copper-containing seed layer and an iron alloy-containing layer, the method comprising the step of etching the copper-containing seed layer using the aqueous composition according to claim 1.

7. 6. A method for manufacturing a semiconductor substrate, in which wiring is formed on the semiconductor substrate having a copper-containing seed layer and a layer containing an iron alloy, the method comprising the step of etching the copper-containing seed layer using the aqueous composition according to claim 1.

8. 7. A kit for use in the etching method of claim 6, comprising (a) a first solution containing hydrogen peroxide and (b) a second solution containing an organic acid, in a mutually unmixed state, and wherein the first solution and the second solution are mixed together at the time of use to prepare the aqueous composition.

9. 8. A kit for use in the method for manufacturing a semiconductor substrate according to claim 7, comprising (a) a first solution containing hydrogen peroxide and (b) a second solution containing an organic acid, which are not mixed with each other, and in which the first solution and the second solution are mixed together at the time of use to prepare the aqueous composition.

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