Aqueous components, etching methods using the same, and methods for manufacturing semiconductor substrates

Abstract

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

Description

Technical Field

[0001] This invention relates to an aqueous composition capable of selectively etching the copper-containing seed layer during wiring formation of a semiconductor substrate having a copper-containing seed layer and an iron-containing alloy layer. Furthermore, this invention relates to an etching method using the aforementioned aqueous composition and a method for manufacturing a semiconductor substrate. Prior Technology

[0002] In the fabrication of wiring on semiconductor substrates, etching solutions are known for etching layers containing copper or copper alloys (e.g., Patent Documents 1 to 3). Furthermore, while nickel-containing bumps are generally used in the fabrication of wiring on semiconductor substrates, bumps containing nickel and iron alloys have gained attention in recent years (e.g., Non-Patent Document 1). [Previous Technical Documents] [Patent Literature]

[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 Literature 1] J.-K. Koo and J.-H. Lee, Materials Transactions, Vol. 58, No.2 (2017) pp. 148-151 Summary of the Invention

[0005] [The problem that the invention aims to solve] Previously, water-based etching compositions that inhibit the etching of ferroalloys while selectively etching copper or copper alloys were unknown. There is a need for a water-based etching composition suitable for forming wiring in semiconductor substrates with copper-containing seed layers and ferroalloy-containing layers. [Methods for solving problems]

[0006] The inventors of this case provide the following aqueous composition, etching method using the same, and method for manufacturing semiconductor substrate, etc.

[0007] [1] An aqueous composition for etching the copper-containing seed layer in the wiring formation of a semiconductor substrate having a copper-containing seed layer and an iron-containing alloy layer. The aqueous component contains (A) hydrogen peroxide and (B) organic acid, with the mass ratio of (A) hydrogen peroxide to (B) organic acid ranging from 0.04 to 20. The pH value is 0.5~5.0. [2] As described in [1] above, the aqueous composition includes (A) 0.5 to 30% by mass of hydrogen peroxide and (B) 1 to 50% by mass of organic acid, based on the total amount of the aqueous composition. [3] As described in [1] or [2] above, the mass ratio of (A) hydrogen peroxide to (B) organic acid (A) / (B) is in the range of 0.04 to 10. [4] The aqueous composition of any one of [1] to [3] above, wherein, based on the total amount of the aqueous composition, the content of (A) hydrogen peroxide, (B) organic acid and (C) water is 95% or more by mass. [5] The aqueous composition of any of [1] to [4] above includes a corrosion inhibitor selected from the group consisting of (i) nitrogen-containing heterocyclic compounds and (ii) cationic surfactants. [6] An etching method comprising the following steps: In the wiring formation of a semiconductor substrate having a copper-containing seed layer and an iron-containing alloy layer, the copper-containing seed layer is etched using an aqueous composition as described in any of [1] to [5] above. [7] A method for manufacturing a semiconductor substrate, comprising the following steps: In the wiring formation of a semiconductor substrate having a copper-containing seed layer and an iron-containing alloy layer, the copper-containing seed layer is etched using an aqueous composition as described in any of [1] to [5] above. [8] A kit for use in the etching method described above [6], wherein the kit contains (a) a first solution containing hydrogen peroxide and (b) a second solution containing an organic acid in an unmixed state, and the first solution and the second solution are mixed when used to prepare the aqueous composition. [9] A kit for use in the manufacturing method of a semiconductor substrate as described above [7], wherein the kit contains (a) a first solution containing hydrogen peroxide and (b) a second solution containing an organic acid in an unmixed state, and the first solution and the second solution are mixed when used to prepare the aqueous composition. [Effects of the Invention]

[0008] According to the present invention, an aqueous composition suitable for etching a copper-containing seed layer formed by wiring of a semiconductor substrate having a copper-containing seed layer and an iron-containing alloy layer can be provided. Furthermore, according to the present invention, an etching method using the aqueous composition and a method for manufacturing a semiconductor substrate can be provided. In the past, during the wiring formation of semiconductor substrates, the ends of the copper-containing seed layer were sometimes over-etched, resulting in undercut. However, according to the preferred embodiment of the present invention, the performance of suppressing undercut is also excellent. Simple Explanation of the Diagram

[0009] [Figure 1] is a schematic diagram showing an example of the side surface of a semiconductor substrate before etching (a stack with an iron alloy layer). [Figure 2] is a schematic diagram showing the side of the semiconductor substrate before etching treatment used in the evaluation of the embodiments and comparative examples (a stack without an iron alloy layer). [Figure 3] is a schematic diagram showing a portion of the semiconductor substrate in Figure 2. Implementation

[0010] The following description focuses on the aqueous components of the present invention, but the present invention is not limited thereto, and various modifications can be made without departing from its concept.

[0011] <1. Aqueous components> The aqueous composition of the present invention comprises at least (A) hydrogen peroxide and (B) an organic acid, wherein the mass ratio of (A) hydrogen peroxide to (B) organic acid (A) / (B) is in the range of 0.04 to 20, and the pH value is 0.5 to 5.0. Preferably, the aqueous composition of the present invention, based on the total amount of the aqueous composition, comprises 0.5 to 30% by mass of (A) hydrogen peroxide and 1 to 50% by mass of (B) organic acid.

[0012] According to a preferred embodiment of the present invention, when the aqueous composition of the present invention contains one or more selected from the group consisting of ferroalloys used as wiring materials, it can suppress the dissolution of such metals while selectively etching copper or copper alloys. According to another preferred embodiment of the present invention, when the composition contains one or more selected from the group consisting of ferroalloys, one or more selected from the group consisting of nickel and nickel alloys, and one or more selected from the group consisting of tin, tin alloys, gold and gold alloys, it can suppress the dissolution of such metals while selectively etching copper and copper alloys. Furthermore, the term "copper alloy" in this specification is not particularly limited as long as copper contains one or more metallic or non-metallic elements and possesses metallic properties. Similarly, the term "ferroalloy" is not particularly limited as long as iron contains one or more metallic or non-metallic elements and possesses metallic properties. The same applies to "nickel alloys," "tin alloys," and "gold alloys." In this specification, the preferred copper concentration of the copper alloy is 50-99.99% by mass, more preferably 60-99.99% by mass, even more preferably 70-99.99% by mass, and most preferably 80-99.99% by mass. Other metal atoms besides copper in the copper alloy should preferably be zinc, tin, lead, aluminum, nickel, etc. Suitable copper alloys include, for example, brass, bronze, cupronickel, nickel silver, beryllium copper, etc. The preferred iron concentration of ferroalloys is 20-90% by mass, more preferably 20-80% by mass, even more preferably 30-60% by mass, and even more preferably 35-65% by mass, or 40-60% by mass. Other metal atoms besides iron in the ferroalloy should preferably be nickel or cobalt. For example, nickel-iron alloys (NiFe) and cobalt-iron alloys (CoFe) are suitable. Furthermore, in this specification, "nickel alloy" refers to an alloy that is not an iron alloy and contains nickel as its main component. The same applies to "tin alloy" and "gold alloy".

[0013] The objects etched using the aqueous composition of the present invention can preferably include a stack of layers containing a copper seed layer and an iron alloy layer; a stack of layers containing a copper seed layer, an iron alloy layer, and a nickel or nickel alloy layer; and a stack of layers containing a copper seed layer, an iron alloy layer, a nickel or nickel alloy layer, and a tin, tin alloy, gold, or gold alloy layer.

[0014] Furthermore, in this specification, "copper-containing seed layer" refers to a metal layer containing copper or a copper alloy, which serves as the substrate layer in the wiring formation of the semiconductor substrate. The copper-containing seed layer is preferably formed using sputtering or electroless plating methods. The "iron alloy layer" is formed on top of the seed layer and serves as a wiring material for a semiconductor substrate, for example, as one of the raised metal layers of the semiconductor substrate. The iron alloy layer is preferably formed using electroplating or similar methods. The "nickel-containing or nickel alloy-containing layer", "tin-containing or tin alloy-containing layer", and "gold-containing or gold alloy-containing layer" are also formed on the seed layer and, together with the iron alloy-containing layer, are used as wiring materials for the semiconductor substrate, for example, as one of the raised metal layers of the semiconductor substrate. These layers are preferably formed by electroplating or the like.

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

[0016] The following provides a detailed description of each component contained in the aqueous composition of the present invention.

[0017] (A) Hydrogen peroxide In the aqueous composition of this invention, hydrogen peroxide primarily functions as an oxidizing agent for copper oxidation. The hydrogen peroxide contained in the aqueous composition is typically used in the form of an aqueous solution of appropriate concentration mixed with other components. The concentration of hydrogen peroxide in the aqueous solution is not particularly limited; for example, it can be 10-90%, but 35%-60% is preferred according to industrial specifications. Hydrogen peroxide may contain up to about 0.01% by mass of a stabilizer. Permissible stabilizers include, for example, sulfuric acid and phosphoric acid. The manufacturing steps and processes of hydrogen peroxide are not limited to; for example, hydrogen peroxide produced using the anthraquinone process may be used.

[0018] The hydrogen peroxide content, based on the total amount of the aqueous components, is preferably 0.5-30% by mass, more preferably 1.0-27% by mass, even more preferably 1.5-25% by mass, and even more preferably 2.0-22% by mass, 2.5-20% by mass, or 3.0-20% by mass, etc. Furthermore, the lower limit of hydrogen peroxide content is based on the total amount of aqueous components, and can be, for example, 0.5% by mass, 1.0% by mass, 1.5% by mass, 2.0% by mass, 2.5% by mass, or 3.0% by mass. The upper limit, also based on the total amount of aqueous components, can be, for example, 30% by mass, 25% by mass, 20% by mass, 15% by mass, 10% by mass, or 5% by mass. The range of hydrogen peroxide content can be selected by combining the above lower and upper limits. If the hydrogen peroxide content is within the above range, a good etching rate can be achieved for the copper-containing seed layer, while suppressing unnecessary dissolution of the wiring material.

[0019] (B) Organic acids In the aqueous composition of this invention, the organic acid mainly functions as an etchant for copper oxidized by hydrogen peroxide. Organic acids are not particularly limited to any organic compound containing a carboxyl group. Examples of organic acids include aliphatic carboxylic acids, aromatic carboxylic acids, and amino acids. Among these, aliphatic and aromatic carboxylic acids are preferred, and it is even more preferable to select one or more from the group consisting of aliphatic carboxylic acids with 1 to 12 carbon atoms and aromatic carboxylic acids with 6 to 16 carbon atoms.

[0020] Aliphatic carboxylic acids, for example, include formic acid, acetic acid, propionic acid, lactic acid, glycolic acid, diethanolic acid, pyruvic acid, oxalic acid, malonic acid, butyric acid, hydroxybutyric acid, tartaric acid, succinic acid, malic acid, maleic acid, fumaric acid, valeric acid, glutaric acid, itconic acid, adipic acid, hexanoic acid, citric acid, propane tricarboxylic acid, trans-aconic acid, heptanoic acid, caprylic acid, nonanoic acid, decanoic acid, lauric acid, myristic acid, palmitic acid, sorbic acid, iminodiacetic acid, ethylenediamine-4-acetic acid, diethylenetriamine-5-acetic acid, triethylenetetramine-6-acetic acid, and diaminocyclohexane-4-acetic acid, etc. These can be used in one or in combination of two or more.

[0021] Aromatic carboxylic acids, for example, 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, and 2-cyanobenzoic acid. 3-Cyanobenzic acid, 4-Cyanobenzic 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 Formic acid, 3-hydroxy-4-methylbenzoic acid, 3-hydroxy-5-methylbenzoic 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 Benzoic acid, 3,6-dihydroxybenzoic acid, 2,4,5-trimethylbenzoic acid, 2,4,6-trimethylbenzoic acid, 1-naphthylcarboxylic acid, 2-naphthylcarboxylic acid, 1-hydroxy-2-naphthylcarboxylic acid, 6-hydroxy-1-naphthylcarboxylic acid, 6-hydroxy-2-naphthylcarboxylic acid, 2-hydroxy-1-naphthylcarboxylic acid, 3-hydroxy-2-naphthylcarboxylic acid, 1,4-dihydroxy-2-naphthylcarboxylic acid, 1-anthracarboxylic acid, 2-anthracarboxylic acid, 9-anthracarboxylic acid, gallic acid, benzohexacarboxylic acid, and cinnamic acid, etc. These can be used in one or in combination of two or more.

[0022] Organic acids may be used, either aliphatic carboxylic acids or aromatic carboxylic acids, or both aliphatic carboxylic acids and aromatic carboxylic acids. Among them, aliphatic carboxylic acids are preferred organic acids, citric acid, lactic acid, malonic acid, and combinations of two or more of these are even better, and combinations of citric acid, lactic acid, and these are even better.

[0023] The content of organic acids, based on the total amount of aqueous components, is preferably 1-50% by mass, more preferably 3-45% by mass, even more preferably 5-40% by mass, and even more preferably 7-35% by mass, 8-32% by mass, or 10-30% by mass, etc. Furthermore, the lower limit of the organic acid content is based on the total amount of the aqueous components, and can be, for example, 1.0% by mass, 2.0% by mass, 3.0% by mass, 4.0% by mass, 5.0% by mass, 6.0% by mass, 7.0% by mass, 8.0% by mass, 9.0% by mass, or 10.0% by mass. The upper limit, based on the total amount of the aqueous components, can be, for example, 50% by mass, 45% by mass, 40% by mass, 35% by mass, 30% by mass, 25% by mass, 20% by mass, or 15% by mass. The range of organic acid content can be selected by combining the above lower and upper limits. If the content of organic acid is within the above range, a good etching rate for the copper-containing seed layer can be achieved, while suppressing unnecessary dissolution of wiring materials.

[0024] In the aqueous composition of the present invention, the mass ratio of (A) hydrogen peroxide to (B) organic acid (A) / (B) is 0.04~20, preferably 0.04~10, more preferably 0.04~8, even more preferably 0.04~6, and even more preferably 0.06~4. The lower limit of the mass ratio (A) / (B) can be, for example, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, or 0.1, etc., and the upper limit can 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 hydrogen peroxide content can be selected from the range formed by combining the above lower and upper limits. If the mass ratio (A) / (B) is within the above range, the etching of the iron alloy will be suppressed, while the copper-containing seed layer can be selectively etched.

[0025] (C) Water The water contained in the aqueous composition of this invention is preferably water from which metal ions, organic impurities, particles, etc., have been removed by distillation, ion exchange treatment, filtration treatment, various adsorption treatments, etc., and pure water is preferred, especially ultrapure water. The water content in the aqueous composition can be appropriately adjusted according to the content of other components in the aqueous composition, and there is no particular limitation, but based on the total amount of the aqueous composition, for example, it is 40~98% by mass, preferably 50~95% by mass, and more preferably 60~90% by mass.

[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% by mass or more, more preferably 96% by mass or more, even more preferably 97% by mass or more, and even more preferably 98% by mass or more, 99% by mass or more, or 99.5% by mass or more, based on the total amount of the aqueous composition.

[0027] (D) Corrosion Inhibitor The aqueous composition of this invention may also include corrosion inhibitors as needed. In the aqueous composition, the corrosion inhibitor primarily forms an anti-corrosion layer on the surface through reaction with or adsorption onto the surface of metals such as copper, copper alloys, ferroalloys, or nickel. This can effectively inhibit corrosion of layers containing metals with a higher ionization tendency than copper, such as ferroalloys and nickel, especially galvanic corrosion. Furthermore, the corrosion inhibitor also inhibits excessive etching, i.e., undercutting, of copper-containing seed layers. For example, (i) nitrogen-containing heterocyclic compounds and (ii) cationic surfactants are suitable corrosion inhibitors. These may be a single agent or a combination of two or more.

[0028] The total content of corrosion inhibitors, based on the total amount of aqueous components, is preferably 0.00001~5.0% by mass, more preferably 0.0001~3.0% by mass, even more preferably 0.0005~1.0% by mass, and even more preferably 0.001~0.5% by mass. Adjusting the content of corrosion inhibitors to the aqueous components within the above range can suppress excessive etching, i.e., undercutting, of the copper-containing layer.

[0029] (i) Nitrogen-containing heterocyclic compounds Nitrogen-containing heterocyclic compounds, preferably comprising at least a nitrogen-containing 5-membered ring compound. The nitrogen-containing 5-membered ring compound may also have one or more substituents selected from the group consisting of a substituted amino group having one or more substituents selected from the group consisting of alkyl, amino, alkyl, and phenyl groups having 1 to 6 carbon atoms. Furthermore, the nitrogen-containing heterocyclic compound may also contain rings other than the nitrogen-containing 5-membered ring, such as aliphatic rings having 5 to 30 carbon atoms, aromatic rings having 6 to 30 carbon atoms, etc., and may also contain condensed rings of such rings and the nitrogen-containing 5-membered ring. The nitrogen-containing 5-membered ring compound, for example, is selected from one or more of the group consisting of pyrrole, pyrazole, imidazole, triazole, and tetraazole. The nitrogen-containing 5-membered ring compound may be only one type, or may consist of two or more types.

[0030] Nitrogen-containing 5-membered ring compounds, preferably those shown in formula (1), formula (2) or formula (3): [Chemistry 1] In formulas (1) to (3), R1, R2, R3, R4 and R5 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 alkyl groups having 1 to 6 carbon atoms and phenyl groups, or R2 and R3 can also bond with each other to form an aliphatic ring with 5 to 30 carbon atoms or an aromatic ring with 6 to 30 carbon atoms. R4 and R5 can also bond with each other to form an aliphatic ring with 5 to 30 carbon atoms or an aromatic ring with 6 to 30 carbon atoms. The number of carbon atoms in the aforementioned aliphatic rings is preferably 6 to 24, more preferably 6 to 16 or 8 to 12, and the number of carbon atoms in the aromatic rings is preferably 6 to 24, more preferably 6 to 16 or 8 to 12.

[0031] Alkyl groups having 1 to 6 carbon atoms can include straight-chain or branched alkyl groups and cycloalkyl groups. Examples of straight-chain or branched alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, dibutyl, tributyl, n-pentyl, n-hexyl, etc. Examples of cycloalkyl groups having 3 to 6 carbon atoms include cyclopropyl, cyclopentyl, cyclohexyl, etc. Among these, methyl or ethyl is preferred, with methyl being particularly preferred.

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

[0033] Preferred examples of nitrogen-containing 5-membered ring compounds include 5-methyltetrazole, 5-aminotetrazole, 1,2,4-triazole, 3-amino-1,2,4-triazole, 1,2,3-triazole, and tetrazolium and benzotriazole (1,2,3-benzotriazole). Among these, it is particularly preferred to select one or more from the group consisting of 1,2,4-triazole, 3-amino-1,2,4-triazole, 5-methyltetrazole, 5-aminotetrazole and 1,2,3-benzotriazole. In addition to those represented by formulas (1) to (3) above, pyrrole, pyrazole, and compounds whose cyclic skeleton contains the substituents shown by R1 to R5 above are preferred.

[0034] Furthermore, nitrogen-containing heterocyclic compounds are those other than nitrogen-containing 5-membered ring compounds. For example, regarding nitrogen-containing 6-membered ring compounds, pyridine, pyrimidine, pyrimidine, triazine, tetraazine, pentaazine, hexaazine, and compounds whose ring skeleton contains the substituents shown in R1 to R5 above are preferred. Nitrogen-containing heterocyclic compounds can be of only one type or a combination of two or more types.

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

[0036] (ii) Cationic surfactants Cationic surfactants, preferably including alkyl-containing quadrivalent ammonium hydroxides or their salts, and alkyl-containing heteroaryl hydroxides or their salts. (a) Alkyl-containing fourth-order ammonium hydroxides or their salts A preferred example of an alkyl-containing fourth-order ammonium hydroxide or its salt is represented by the following formula (4). [Chemistry 2]

[0037] In formula (4) above, R6 refers to substituted or unsubstituted alkyl groups with 4 to 30 carbon atoms, substituted or unsubstituted alkyl (poly)hexaalkyl groups with 4 to 30 carbon atoms, or substituted or unsubstituted aryl (poly)hexaalkyl groups with 4 to 30 carbon atoms.

[0038] Alkyl groups with 4 to 30 carbon atoms, without particular limitation, can be listed as butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, decadecyl, hexadecyl, heptyl, octadecyl, decylene, didecyl, didecylene ...

[0039] When a substituted or unsubstituted alkyl group has 4 to 30 carbon atoms, the substituent is not particularly limited, and examples include halogen atoms such as fluorine, chlorine, bromine, and iodine; aryl groups with 6 to 20 carbon atoms such as phenyl and naphthyl; alkoxy groups with 1 to 6 carbon atoms such as methoxy, ethoxy, and propoxy; hydroxyl groups; cyano groups; and nitro groups. Furthermore, there may be one or more substituents. Also, "substituted alkyl group with 4 to 30 carbon atoms" means that the total number of carbon atoms in the substituent and the alkyl group is 4 to 30. That is, among the substituted alkyl groups with 4 to 30 carbon atoms, the total number of carbon atoms in the substituent is within the above range, and may include alkyl groups with 4 or more carbon atoms (e.g., alkyl groups with 4 to 13 carbon atoms such as butyl, hexyl, octyl, decyl, and dodecyl).

[0040] Alkyl (poly)hexaalkyl groups with 4 to 30 carbon atoms are represented as -(CnH2n-Z-)m-R8. In this case, n is independently 1 to 5, preferably 1 to 3, and more preferably 1 to 2. m is 1 to 5, preferably 1 to 2. Z is independently an oxygen atom (O), a sulfur atom (S), or a phosphorus atom (P), preferably an oxygen atom (O). Examples of R8 alkyl groups with 1 to 30 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, decadecyl, hexadecyl, hexadecyl, heptadeca, octadecyl, nonadecadecyl, and icosyl.

[0041] When a substituted or unsubstituted alkyl (poly)hexaalkyl group with 4 to 30 carbon atoms has a substituent (substituted alkyl (poly)hexaalkyl group with 4 to 30 carbon atoms), the substituent is not particularly limited and can include halogen atoms such as fluorine, chlorine, bromine, and iodine; aryl groups with 6 to 20 carbon atoms such as phenyl and naphthyl; alkoxy groups with 1 to 6 carbon atoms such as methoxy, ethoxy, and propoxy; hydroxyl groups; cyano groups; and nitro groups. Furthermore, the substituent is usually a hydrogen atom replacing R8. There can be one substituent or two or more. Moreover, substituted alkyl (poly)hexaalkyl group with 4 to 30 carbon atoms means that the total number of carbon atoms in the substituent and the alkyl (poly)hexaalkyl group is 4 to 30. That is, among the substituted alkyl (poly)hexaalkyl groups having 4 to 30 carbon atoms, the total number of carbon atoms of the substituents is within the above range, and may include alkyl (poly)hexaalkyl groups having 4 or more carbon atoms (e.g., alkyl groups having 4 to 13 carbon atoms such as butyl, hexyl, octyl, decyl, and dodecyl).

[0042] Aryl (poly)hexaalkyl groups with 4 to 30 carbon atoms are represented by -(CnH2n-Z-)m-Ar. In this case, n is independently 1 to 5, preferably 1 to 3, and more preferably 1 to 2. m is 1 to 5, preferably 1 to 2. Z is independently an oxygen atom (O), a sulfur atom (S), or a phosphorus atom (P), preferably an oxygen atom (O). Ar refers to aryl groups with 6 to 18 carbon atoms, such as phenyl, naphthyl, and anthracene.

[0043] When a substituted or unsubstituted aryl (poly)hexaalkyl group with 4 to 30 carbon atoms has a substituent (substituted aryl (poly)hexaalkyl group with 4 to 30 carbon atoms), the substituent is not particularly limited and can include halogen atoms such as fluorine, chlorine, bromine, and iodine; alkyl groups with 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 with 1 to 6 carbon atoms such as methoxy, ethoxy, and propoxy; hydroxyl; cyano; and nitro. Furthermore, the substituent is usually a hydrogen atom replacing Ar. There can be one substituent or two or more substituents. Moreover, substituted aryl (poly)hexaalkyl group with 4 to 30 carbon atoms means that the total number of carbon atoms in the substituent and the aryl (poly)hexaalkyl group is 4 to 30. That is, among the substituted aryl (poly)hexaalkyl groups with 4 to 30 carbon atoms, the total number of carbon atoms of the substituents is within the above range, and may include aryl (poly)hexaalkyl groups with 4 or more carbon atoms (for example, alkyl groups with 4 to 13 carbon atoms such as butyl, hexyl, octyl, decyl, and dodecyl).

[0044] In one embodiment, R6 is preferably a substituted or unsubstituted alkyl (poly)hexaalkyl group with 4 to 30 carbons, or a substituted or unsubstituted aryl (poly)hexaalkyl group with 4 to 30 carbons, more preferably a substituted or unsubstituted aryl (poly)hexaalkyl group with 6 to 20 carbons, even more preferably a substituted or unsubstituted aryl (poly)hexaalkyl group with 8 to 20 carbons, and especially preferably a substituted or unsubstituted aryl (poly)hexaalkyl group with 10 to 18 carbons, with (1,1,3,3-tetramethylbutyl)phenyldi(oxyethyl)(p-CH3C(CH3)2CH2C(CH3)2-Ph-(O-C2H4)2-) group being the most suitable.

[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)hexaalkyl group having 4 to 25 carbon atoms, and even more preferably a substituted or unsubstituted alkyl group having 6 to 20 carbon atoms, or a substituted or unsubstituted aryl (poly)hexaalkyl group having 6 to 20 carbon atoms. Dodecyl, tetradecyl, hexadecyl, octadecyl, and p-(1,1,3,3-tetramethylbutyl)phenyldi(oxyethyl) (p-CH3C(CH3)2CH2C(CH3)) 2-Ph-(O-C2H4)2-) group is preferred, hexadecyl, octadecyl, and p-(1,1,3,3-tetramethylbutyl)phenyldi(oxyethyl))(p-CH3C(CH3)2CH2C(CH3)2-Ph-(O-C2H4)2-) group are especially preferred, and p-(1,1,3,3-tetramethylbutyl)phenyldi(oxyethyl))(p-CH3C(CH3)2CH2C(CH3)2-Ph-(O-C2H4)2-) group is the best.

[0046] Furthermore, each of R7 is 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] Alkyl groups having 1 to 30 carbon atoms, without particular limitation, including methyl, ethyl, propyl, isopropyl, butyl, isobutyl, dibutyl, tributyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecimal, octadecyl, nonadecimal, icosyl, etc.

[0048] When a substituted or unsubstituted alkyl group has 1 to 30 carbon atoms, the substituents can include halogen atoms such as fluorine, chlorine, bromine, and iodine; aryl groups with 6 to 20 carbon atoms such as phenyl and naphthyl; alkoxy groups with 1 to 6 carbon atoms such as methoxy, ethoxy, and propoxy; hydroxyl groups; cyano groups; and nitro groups. Furthermore, there can be one or more substituents. "Substituent alkyl group with 1 to 30 carbon atoms" means that the total number of carbon atoms in the substituent and the alkyl group is 1 to 30.

[0049] Aryl groups with 6 to 30 carbon atoms are not particularly limited; examples include phenyl, naphthyl, and biphenyl.

[0050] When a substituted or unsubstituted aryl group has 6 to 30 carbon atoms, the substituents (for substituted aryl groups with 6 to 30 carbon atoms) can include halogen atoms such as fluorine, chlorine, bromine, and iodine; alkyl groups with 1 to 10 carbon atoms such as methyl, ethyl, propyl, and isopropyl; alkoxy groups with 1 to 6 carbon atoms such as methoxy, ethoxy, and propoxy; hydroxyl groups; cyano groups; and nitro groups. Furthermore, there can be one or more substituents. Also, "substituted aryl group with 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, R7 is preferably a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, with methyl, ethyl, propyl, isopropyl, hexyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, benzyl, hydroxymethyl, and 2-hydroxyethyl being more preferred, methyl, ethyl, benzyl, and 2-hydroxyethyl being even more preferred, methyl and benzyl being particularly preferred, and methyl being the best. In another embodiment, R7 is preferably an alkyl group having 1 to 10 carbon atoms substituted with an aryl group having 6 to 20 carbon atoms, with alkyl groups having 1 to 5 carbon atoms substituted with a phenyl group being more preferred, with benzyl and phenylethyl being even more preferred, and benzyl being particularly preferred.

[0052] The following are considered suitable ion types: X-series halide ions (fluoride, chloride, bromide, iodide, etc.), hydroxide ions, organic sulfonic acid ions (methanesulfonate, p-toluenesulfonate, etc.), tetrafluoroborate anion, and hexafluorophosphate anion. Among these, halogen ions are preferred, with chloride and bromide ions being even more desirable.

[0053] R6 represents specific examples of ammonium salts of formula (4) with substituted or unsubstituted alkyl groups having 4 to 30 carbon atoms, such as butyltrimethylammonium bromide, benzyl dimethylbutylammonium chloride, etc., which contain a butyl group; hexyltrimethylammonium bromide, benzyl dimethylhexylammonium chloride, etc., which contain a hexyl group; octyltrimethylammonium bromide, benzyl dimethyloctylammonium chloride, etc., which contain an octyl group; decyltrimethylammonium bromide, benzyl dimethyldecylammonium chloride, etc., which contain a decyl group; dodecyltrimethylammonium bromide, benzyl dimethyl dodecylammonium chloride, etc., which contain a dodecyl group; bromide Ammonium salts containing the decyl group include tetradecyltrimethylammonium salt and benzyldimethyltetradecylammonium chloride; ammonium salts containing the decyl group include hexadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, hexadecyltrimethyl-p-toluenesulfonate ammonium salt, hexadecyltrimethylammonium hydroxide, ethylhexadecyldimethylammonium chloride, ethylhexadecyldimethylammonium bromide, and benzyldimethylhexadecylammonium chloride; and ammonium salts containing the octadecyl group include trimethyloctadecylammonium chloride, trimethyloctadecylammonium bromide, dimethyldioctadecylammonium chloride, dimethyldioctadecylammonium bromide, and benzyldimethyloctadecylammonium chloride.

[0054] R6 is a specific example of an ammonium salt represented by formula (4) of a substituted or unsubstituted alkyl (poly)hexaalkyl group having 4 to 30 carbon atoms, such as trimethylpropyl di(oxyethyl)ammonium chloride, trimethylpropyl oxyethylthioethylammonium chloride, etc.

[0055] R6 is an ammonium salt represented by formula (4) of a substituted or unsubstituted aryl (poly)hexaalkyl group having 4 to 30 carbon atoms. Examples include benzyl dimethyl-2-{2-[4-(1,1,3,3-tetramethylbutyl)phenoxy]ethoxy}ethyl ammonium salt (benzoxonine chloride), benzyl dimethylphenyl di(oxyethyl) ammonium salt, etc.

[0056] In one embodiment, the ammonium salt represented by formula (4) above is preferably a substituted or unsubstituted aryl (poly)hexaalkyl group of R6 with 4 to 30 carbons, preferably a substituted or unsubstituted aryl group of R7 with 6 to 30 carbons, preferably a substituted or unsubstituted aryl (poly)hexaalkyl group of R6 with 8 to 20 carbons, preferably a substituted or unsubstituted aryl group of R7 with 6 to 15 carbons, preferably a substituted or unsubstituted aryl (poly)hexaalkyl group of R6 with 10 to 18 carbons, preferably a substituted or unsubstituted aryl group of R7 with 6 to 12 carbons, and especially preferably benzyl dimethyl-2-{2-[4-(1,1,3,3-tetramethylbutyl)phenoxy]ethoxy}ethylammonium salt (benzoxonine chloride).

[0057] (b) Alkyl-containing heteroaryl hydroxides or their salts Preferred examples of heteroaryl hydroxides containing alkyl groups or their salts may be listed as heteroaryl hydroxides or their salts having substituted or unsubstituted alkyl groups having 4 to 30 carbon atoms. Salts of heteroaryl groups having substituted or unsubstituted alkyl groups having 4 to 30 carbon atoms are preferred, preferably heteroaryl rings containing substituted or unsubstituted nitrogen atoms, and salts of heteroaryl cations formed by bonding at least one nitrogen atom of the substituted or unsubstituted nitrogen-containing heteroaryl ring to a substituted or unsubstituted alkyl group having 4 to 30 carbon atoms are even more preferred.

[0058] The aforementioned nitrogen-containing heteroaromatic rings are not particularly limited and can include imidazole, pyrazole, succinazole, isoxazole, thiazole, isothiazole, pyridine, pyridine, pyrazine, pyrazine, pyrimidine, quinoline, isoquinoline, etc.

[0059] Substituents in a nitrogen-containing heteroaromatic ring when it has a substituent other than a substituted or unsubstituted alkyl group having 4 to 30 carbon atoms 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 propoxy; hydroxyl groups; cyano groups; and nitro groups.

[0060] Alkyl groups with 4 to 30 carbon atoms, without particular limitation, can be listed as butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, decadecyl, hexadecyl, heptyl, octadecyl, decylene, didecyl, didecylene ...

[0061] When a substituted or unsubstituted alkyl group has 4 to 30 carbon atoms, the substituents can include halogen atoms such as fluorine, chlorine, bromine, and iodine; alkyl groups with 1 to 4 carbon atoms such as methyl, ethyl, propyl, and isopropyl; aryl groups with 6 to 20 carbon atoms such as phenyl and naphthyl; alkoxy groups with 1 to 6 carbon atoms such as methoxy, ethoxy, and propoxy; hydroxyl groups; cyano groups; and nitro groups. Furthermore, there can be one or more substituents. Also, "substituted alkyl group with 4 to 30 carbon atoms" means that the total number of carbon atoms of the substituents and the alkyl group is 4 to 30. That is, among the substituted alkyl groups with 4 to 30 carbon atoms, those whose total number of carbon atoms of the substituents falls within the above range can include alkyl groups with 4 or more carbon atoms (e.g., alkyl groups with 4 to 13 carbon atoms such as butyl, hexyl, octyl, decyl, and dodecyl).

[0062] Among these, substituted or unsubstituted alkyl groups with 4 to 30 carbon atoms are preferred, substituted or unsubstituted alkyl groups with 8 to 20 carbon atoms are even more preferred, alkyl groups with 12 to 18 carbon atoms are even more preferred, and dodecyl, tetradecyl, hexadecyl, and octadecyl are even more preferred. Considering the view that they can suppress the undercut of copper-containing seed layers, dodecyl, tetradecyl, and hexadecyl are especially preferred.

[0063] The relative anions of heteroaryl cations having substituted or unsubstituted alkyl groups with 4 to 30 carbon atoms are not particularly limited, and examples include halide ions such as fluoride ions, chloride ions, bromide ions, and iodide ions; hydroxide ions; organic sulfonic acid ions such as methanesulfonate ions and p-toluenesulfonate ions; tetrafluoroborate anions; and hexafluorophosphate anions. Among these, halide ions are preferred, and chloride ions and bromide ions are even more preferred.

[0064] Specific examples of heteroaryl salts having substituted or unsubstituted alkyl groups 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-methylimidazolium chloride, 1-dodecyl-3-methylimidazolium bromide, 1-tetradecyl-3-methylimidazolium chloride, and 1-tetradecyl-3-methylimidazolium bromide. Imidazolium salts include 1-hexadecimal-3-methylimidazolium chloride, 1-hexadecimal-3-methylimidazolium bromide, 1-octadecyl-3-methylimidazolium chloride, and 1-octadecyl-3-methylimidazolium bromide; 3-butyl acezoline chloride, 3-hexyl acezoline chloride, 3-octyl acezoline chloride, 3-decyl acezoline chloride, 3-dodecyl acezoline chloride, 3-tetradecyl acezoline chloride, 3-hexadecimal acezoline chloride, and 3-octadecyl acezoline chloride; and 3-butylthiazoline chloride, 3-hexylthiazoline chloride, 3-octylthiazoline chloride, and 3-... Thiazoleonium salts including decylthiazolium chloride, 3-dodecylthiazolium chloride, 3-tetradecylthiazolium chloride, 3-hexadecathiazolium chloride, and 3-octadecylthiazolium chloride; pyridineonium salts including 1-butylpyridinium chloride, 1-hexylpyridinium chloride, 1-octylpyridinium chloride, 1-decylpyridinium chloride, 1-dodecylpyridinium chloride, 1-tetradecylpyridinium chloride, 1-tetradecylpyridinium bromide, 1-hexadecathiazolium chloride, 1-hexadecathiazolium bromide, 1-octadecylpyridinium chloride, and 1-octadecylpyridinium bromide; pyridineonium salts including 1-butylpyrimidineonium chloride and 1-hexadecathiazolium chloride. Pyrimidine onion salts such as 1-octylpyrimidine onion salt, 1-decylpyrimidine onion salt, 1-dodecylpyrimidine onion salt, 1-tetradecylpyrimidine onion salt, 1-hexadecylpyrimidine onion salt, and 1-octadecylpyrimidine onion salt; quinoline onion salts such as butylquinoline onion salt, hexylquinoline onion salt, octylquinoline onion salt, decylquinoline onion salt, dodecylquinoline onion salt, tetradecylquinoline onion salt, hexadecylquinoline onion salt, and octadecylquinoline onion salt; and isoquinoline onion salts such as decyl isoquinoline onion salt, dodecyl isoquinoline onion salt, tetradecyl isoquinoline onion salt, hexadecyl isoquinoline onion salt, and octadecyl isoquinoline onion salt. Furthermore, these can also be used in the form of hydrates.

[0065] Of these, (ii) the cationic surfactant is preferably an ammonium salt represented by formula (4) (here, R6 is a substituted or unsubstituted alkyl group having 8 to 20 carbons, or a substituted or unsubstituted aryl (poly)hexaalkyl group having 8 to 20 carbons), an imidazolium salt having a substituted or unsubstituted alkyl group having 8 to 20 carbons, or a pyridinium salt having a substituted or unsubstituted alkyl group having 8 to 20 carbons, and preferably an ammonium salt represented by formula (4) (here, R6 is a substituted or unsubstituted aryl (poly)hexaalkyl group having 12 to 20 carbons, and at least one of R7 is a substituted or unsubstituted aryl group having 6 to 12 carbons), an imidazolium salt having a substituted or unsubstituted alkyl group having 10 to 18 carbons, or a substituted or unsubstituted alkyl group having 10 to 18 carbons. Alkyl pyridinium salts are preferred, ammonium salts represented by formula (4) (where R6 is a substituted or unsubstituted aryl (poly)hexaalkyl group having 12 to 18 carbons, and at least one of R7 is a substituted or unsubstituted aryl group having 6 to 12 carbons), imidazolium salts having substituted or unsubstituted alkyl groups having 12 to 18 carbons, pyridinium salts having substituted or unsubstituted alkyl groups having 12 to 18 carbons are even more preferred, ammonium salts represented by formula (4) (where R6 is a substituted or unsubstituted aryl (poly)hexaalkyl group having 12 to 16 carbons, and at least one of R7 is a substituted or unsubstituted aryl group having 6 to 12 carbons), pyridinium salts having substituted or unsubstituted alkyl groups having 12 to 16 carbons are particularly preferred, benzoxonine chloride and benzoxonine bromide are the best.

[0066] Furthermore, the above-mentioned cationic surfactant (ii) can be used in combination with only one type or in combination with two or more types. That is, in a preferred embodiment, (ii) the cationic surfactant comprises at least one selected from the group consisting of an ammonium salt represented by formula (4) (here, R6 is a substituted or unsubstituted alkyl group having 10 to 20 carbons, or a substituted or unsubstituted aryl (poly)hexaalkyl group having 10 to 20 carbons), an imidazolium salt having a substituted or unsubstituted alkyl group having 10 to 20 carbons, and a pyridinium salt having a substituted or unsubstituted alkyl group having 10 to 20 carbons, preferably comprising an ammonium salt represented by formula (4) (here, R6 is a substituted or unsubstituted aryl (poly)hexaalkyl group having 16 to 20 carbons, and at least one of R7 is a substituted or unsubstituted aryl group having 6 to 12 carbons), an imidazolium salt having a substituted or unsubstituted alkyl group having 10 to 16 carbons, and a pyridinium salt having a substituted or unsubstituted alkyl group having 10 to 16 carbons, preferably comprising the group consisting of an ammonium salt represented by formula (4) (here, R6 is a substituted or unsubstituted aryl (poly)hexaalkyl group having 16 to 20 carbons, and at least one of R7 is a substituted or unsubstituted aryl group having 6 to 12 carbons), an imidazolium salt having a substituted or unsubstituted alkyl group having 10 to 16 carbons, and a pyridinium salt having a substituted or unsubstituted alkyl group having 10 to 16 carbons). At least one of the following is preferred: a salt of ammonium salt represented by formula (4) (where R6 is a substituted or unsubstituted aryl (poly)hexaalkyl group having 18 to 20 carbon atoms, and at least one of R7 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 14 carbon atoms, and a pyridinium salt having a substituted or unsubstituted alkyl group having 10 to 14 carbon atoms. It is preferred to include at least one of the following groups consisting of ammonium salts represented by formula (4) (where R6 is a substituted or unsubstituted aryl (poly)hexaalkyl group having 18 to 20 carbon atoms, and at least one of R7 is a substituted or unsubstituted aryl group having 6 to 12 carbon atoms) and pyridinium salts having substituted or unsubstituted alkyl groups having 10 to 14 carbon atoms, and most preferably to include at least one of the following groups consisting of benzoxanine chloride and benzoxanine bromide.

[0067] (ii) Preferred examples of cationic surfactants include dodecylpyridinium chloride, benzyldimethylhexadecanium chloride, benzylpyridinium chloride, 1-hexadecanium-3-methylimidazolium chloride, and octyltrimethylammonium chloride. (ii) Cationic surfactants may be a single type or a combination of two or more types.

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

[0069] (E) Additives The aqueous composition of the present invention may, in addition to the above-mentioned components, also include additives such as hydrogen peroxide stabilizers, organic solvents, surfactants other than cationic surfactants, chelating agents, defoamers, alkalis, and silicon-containing compounds, without impairing the effectiveness of the aqueous composition of the present invention. For example, alcohols, urea, phenylurea, organic carboxylic acids, organophosphonic acids, organophosphates, and other known substances can be added as hydrogen peroxide stabilizers. Alternatively, potassium hydroxide, lithium hydroxide, cesium hydroxide, triethylamine, ammonia, tetramethylammonium hydroxide, ethanolamine, 1-amino-2-propanol, and other known bases may be added as appropriate. These additives may be a single type or a combination of two or more.

[0070] The pH value of the aqueous component of this 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 even more preferably in the range of 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 component can be adjusted by adding an alkali. Preferred alkalis are as described above.

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

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

[0073] According to the aqueous composition of the present invention, since it inhibits the etching of ferroalloys and can selectively etch copper or copper alloys, the aqueous composition of the present invention is suitable for use as an aqueous composition for etching the copper-containing seed layer in the wiring formation of semiconductor substrates having a copper-containing seed layer and an ferroalloy-containing layer. According to a preferred embodiment, the aqueous composition of the present invention also exhibits excellent suppression of undercutting caused by excessive etching of the ends of the copper-containing seed layer. Specifically, in the measurement method described later, it is preferable to suppress the undercut of the copper-containing seed layer to below 0.5 μm, more preferably to below 0.4 μm, and even more preferably to below 0.35 μm.

[0074] The aqueous composition of the present invention can be prepared by uniformly stirring one or more of (A) hydrogen peroxide, (B) organic acid, and (C) water, and (D) corrosion inhibitor and (E) additive as needed. There are no particular limitations on the stirring method used for these components; any stirring method commonly used in the preparation of aqueous compositions can be employed.

[0075] The aqueous composition of the present invention is suitable for use as the aforementioned aqueous composition for etching the copper-containing seed layer in the wiring formation of a semiconductor substrate having a copper-containing seed layer and an iron alloy layer. The aqueous composition of the present invention is particularly suitable for use in packaging of next-generation DRAM, NAND flash memory, etc., for applications involving iron alloys used as wiring materials with raised treatments. According to the aqueous composition of the present invention, since the dissolution of the iron alloy is suppressed, and copper or copper alloys can be selectively etched, the aforementioned copper-containing seed layer can be selectively etched in the wiring formation of a semiconductor substrate having a copper-containing seed layer and an iron alloy layer. Furthermore, according to a preferred embodiment, the aqueous composition of the present invention, in the above-mentioned uses, optionally includes one or more components selected from the group consisting of nickel, nickel alloys, tin, tin alloys (including SnAg, etc.), gold and gold alloys, in addition to iron alloys used as wiring materials, and includes titanium and titanium alloys as barrier metal layers, etc., and is suitable for use as an aqueous composition that inhibits the dissolution of such metals and selectively etches copper or copper alloys.

[0076] <2. Etching Method> The etching method of the present invention includes the following steps: using the above-mentioned aqueous composition, etching the aforementioned copper-containing seed layer in the wiring formation of a semiconductor substrate having a copper-containing seed layer and an iron-containing alloy layer.

[0077] There are no particular restrictions on the operating temperature of the aqueous component in the etching process, but a temperature of 10~50℃ is preferable, more preferably 20~45℃, and even more preferably 20~40℃. If the temperature of the aqueous component is above 10℃, the etching rate becomes good, thus achieving excellent production efficiency. On the other hand, if the temperature of the aqueous component is below 50℃, changes in the liquid composition are suppressed, keeping the etching conditions constant. Increasing the temperature of the aqueous component will increase the etching rate, but it is also important to consider minimizing changes in the composition of the aqueous component (decomposition of hydrogen peroxide), and thus, an optimal processing temperature should be determined appropriately.

[0078] Furthermore, there are no particular restrictions on the etching time, but 10-150 seconds is preferable, and 30-120 seconds is even better. The processing time can be appropriately selected based on various conditions such as the surface condition of the object being etched, the concentration of the aqueous components, the temperature, and the processing method. For example, in the etching of a copper-containing seed layer, the processing time can be set until the moment the color of the exposed seed layer disappears (the exact etching time, also known as JET). Depending on the needs, the processing time can also be set to be longer than JET.

[0079] There is no particular limitation on the method for contacting the laminate containing a copper seed layer and an iron alloy layer (i.e., the semiconductor substrate before etching) with the aqueous composition. For example, wet etching methods can be used, such as contacting the aqueous composition with the etched object by dripping (single-piece spin processing) or spraying, or immersing the etched object in the aqueous composition. In this invention, any of these methods can be used.

[0080] <3. Manufacturing Method of Semiconductor Substrate> The method for manufacturing a semiconductor substrate of the present invention includes at least the above-described etching step. In one embodiment, the method for manufacturing a semiconductor substrate of the present invention includes the following steps: The step of preparing a semiconductor substrate with a copper-containing seed layer on its surface; The step of forming a resist pattern with an opening pattern that exposes a portion of the seed layer; The surface of the seed layer exposed in the opening of the resist pattern is formed by arranging the following steps in sequence: forming a metal layer A selected from the group consisting of nickel and nickel alloys, a metal layer B selected from the group consisting of iron alloys, and a metal layer C selected from the group consisting of tin, tin alloys, gold and gold alloys; The steps to remove the above-mentioned resist pattern; and The step of etching the exposed portion of the seed layer, which is the seed layer without metal layers A, B, and C obtained in the step of removing the resist pattern, is brought into contact with the aqueous composition. An example of the etching object in the above etching step can be a semiconductor substrate 10 (semiconductor substrate before etching) having the structure shown in FIG1. ​​Furthermore, in the semiconductor substrate manufacturing method of the present invention, as far as the metal layer is concerned, metal layer B is sufficient, while metal layer A and metal layer C can be optionally provided.

[0081] <4 sets> According to one aspect of the present invention, a kit is provided for use in the aforementioned "2. Etching method", wherein the kit contains (a) a first solution containing hydrogen peroxide and (b) a second solution containing an organic acid in an unmixed state, and the first solution and the second solution are mixed during use to prepare the aforementioned aqueous composition. Furthermore, according to another aspect of the present invention, a kit is provided for use in the aforementioned "3. Method for manufacturing a semiconductor substrate", wherein the kit contains (a) a first solution containing hydrogen peroxide and (b) a second solution containing an organic acid in an unmixed state, and the first solution and the second solution are mixed during use to prepare the aforementioned aqueous composition.

[0082] [1st solution] The first solution contains hydrogen peroxide. Additionally, water, stabilizers, etc., may be added as needed.

[0083] Hydrogen peroxide, water, and stabilizers can be used.

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

[0085] [Second solution] The second solution contains organic acids. Furthermore, depending on the need, it may also contain water, corrosion inhibitors, additives, etc.

[0086] Organic acids, water, corrosion inhibitors, and additives can be used as described above.

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

[0088] According to the kit of the present invention, by setting the first solution containing hydrogen peroxide and the second solution containing organic acid to an unmixed state, the decomposition reaction of organic acid and hydrogen peroxide can be prevented.

[0089] In use, the aforementioned kit is used, and an aqueous composition is prepared by mixing the first solution and the second solution. This composition can be used in the aforementioned semiconductor substrate manufacturing method or the aforementioned etching method, etc. In order to adjust the composition of the final composition, water should be further added to the first solution, the second solution, and at least one selected from the group consisting of hydrogen peroxide, organic acid, corrosion inhibitor, water, and additives. [Example]

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

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

[0092] [Examples 2-11] The added components and amounts were modified as shown in Table 1 to manufacture an aqueous composition for etching semiconductor substrates.

[0093] [Comparative Examples 1-11] The added components and amounts were modified as shown in Table 2 to manufacture an aqueous composition for etching semiconductor substrates.

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

[0095] [Evaluation Sample] In all embodiments and comparative examples, the semiconductor substrate 10 (the semiconductor substrate before etching) having the structure shown in FIG2 is used as an evaluation substrate. The semiconductor substrate 10 includes an upper tin-silver alloy (SnAg) layer 14, a nickel (Ni) layer 16 stacked under the SnAg layer 14, and a copper (Cu) layer 12 stacked under the Ni layer 16. Furthermore, in the semiconductor substrate 10, a titanium (Ti) layer 18 is stacked below the Cu layer 12, and the Ti layer 18 is disposed on the substrate 20. Here, SnAg layer 14 is a layer composed of a tin alloy containing 97% by mass of tin (Sn). In each embodiment and comparative example, as shown in FIG. 3, an enlarged view of the area enclosed by the four corners of the dashed lines in FIG. 2, a semiconductor substrate 10 is used, which is 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. Furthermore, the cylindrical protrusion shown in FIG. 2 has a diameter of 12.5 μm and a height of 9 μm.

[0096] Evaluation of JET in Cu layer etching The evaluation sample was cut into 1cm × 1cm pieces (impregnation treatment area: 1cm2). Then, in 50g of the aqueous composition prepared in Examples 1-11 and Comparative Examples 1-11 respectively, the evaluation sample was impregnated at 27°C for a predetermined time and 350rpm using a stir bar. During the impregnation process, the evaluation sample was held with tweezers and impregnated while positioned above the stir bar.

[0097] When evaluating sample immersion, the time required for the color of the substrate surface to change from orange to silver, which is the time required until the color of the copper seed layer disappears, is defined as Cu JET and is used for measurement, starting from the start time of immersion (etching process).

[0098] [Fe solubility in the aqueous composition after NiFe foil treatment] A 1cm × 1cm (impregnation area: 1cm2) sample of NiFe foil was cut from a 42 Invar foil (manufactured by Nilaco AG, 0.05×100×300mm, Fe content 57% by mass).

[0099] In each of Examples 1-11 and Comparative Examples 1-11, 10 g of the aqueous composition was used to immerse NiFe foil samples at 27°C for 10 minutes. The immersed aqueous composition was then diluted 10-20 times with a 1% (w / w) nitric acid aqueous solution to prepare the test sample. The Fe concentration in the test sample was determined using an Avio200 (PerkinElmer) ICP-OES system. The Fe solubility should preferably be below 100 μg / L, more preferably below 50 μg / L, and even more preferably below 30 μg / L.

[0100] [Cu bottom cutting amount] Using the aqueous compositions manufactured in Examples 1-11 and Comparative Examples 1-11, evaluation samples were immersed in a stirred solution at 27°C for twice the Cu JET time (100% OE (over-etching)) and 350 rpm. The treated evaluation samples were then processed in a FIB (Focused Ion Beam) apparatus (Helios G4 UX, Thermo Scientific) to change the protrusion from a circle to a semi-circle when viewed from above. SEM images of the processed evaluation samples were then obtained using the Helios G4 UX (Thermo Scientific). In the SEM images, the horizontal distance from the Ni end face to the Cu end face was defined as the Cu undercut and was measured. The Cu undercut depth should preferably be below 0.5 μm, more preferably below 0.4 μm, and even more preferably below 0.35 μm.

[0101] [Table 1] [Table 2]

[0102] As shown in Table 1, it was confirmed that the use of the aqueous compositions of Examples 1 to 11 suppressed the corrosion of the ferroalloy and selectively etched the copper-containing seed layer. Furthermore, it was confirmed that the use of the aqueous compositions of Examples 1 to 11 suppressed the undercut of the Cu layer 12. On the other hand, when the mass ratio of hydrogen peroxide to organic acid exceeds the range specified in this invention, the etching of copper is time-consuming and unsuitable for etching copper-containing seed layers (Comparative Examples 4 and 5). Furthermore, when the pH range exceeds the range specified in this invention, the undercut of Cu layer 12 becomes larger (Comparative Example 6). Furthermore, regarding acids, when inorganic acids such as phosphoric acid, sulfuric acid, nitric acid, and hydrochloric acid are used instead of organic acids, the undercut of Cu layer 12 will increase (Comparative Examples 1-3 and 7-9).

[0103] 10: Semiconductor substrate 12: Cu layer (seed layer) 14: SnAg layer (top metal layer) 15: NiFe layer (intermediate metal layer) 16: Ni layer (underlying metal layer) 18: Ti layer (barrier metal layer) 20:Substrate

Claims

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

0.

2. As in claim 1, the aqueous component, wherein, Based on the total amount of the aqueous component, it contains (A) 0.5 to 30% by mass of hydrogen peroxide and (B) 1 to 50% by mass of organic acid.

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

4. As in claim 1, the aqueous composition, wherein, Based on the total amount of the aqueous components, the content of (A) hydrogen peroxide, (B) organic acids and (C) water is 95% by mass or more.

5. The aqueous composition of claim 1 includes a corrosion inhibitor selected from the group consisting of (i) nitrogen-containing heterocyclic compounds and (ii) cationic surfactants.

6. An etching method comprising the following steps: In the wiring formation of a semiconductor substrate having a copper-containing seed layer and an iron-containing alloy layer, etching the copper-containing seed layer using an aqueous composition of any one of claims 1 to 5.

7. A method for manufacturing a semiconductor substrate, comprising the following steps: In the wiring formation of a semiconductor substrate having a copper-containing seed layer and an iron-containing alloy layer, etching the copper-containing seed layer using an aqueous composition as described in any one of claims 1 to 5.

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

9. A kit for use in a method of manufacturing a semiconductor substrate as claimed in claim 7, the kit containing (a) a first solution containing hydrogen peroxide and (b) a second solution containing an organic acid in an unmixed state, and the first solution and the second solution are mixed upon use to prepare the aqueous composition.

Images