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

Abstract

According to the present invention, it is possible to provide an aqueous composition for etching, the aqueous composition containing an oxidizing agent, an acid, and a corrosion inhibitor, the aqueous composition having a pH of 0-3. Preferably, the aqueous composition contains 0.001 to 20 mass% of the oxidizing agent, 0.1 to 50 mass% of the acid, and 0.00001 to 5.0 mass% of the corrosion inhibitor, based on the total amount of the aqueous composition, based on the total amount of the aqueous composition.

Description

Technical Field

[0001] The present invention relates to an aqueous composition for etching, and particularly to an aqueous composition for etching capable of selectively etching a layer containing copper or a copper alloy. Further, the present invention relates to an etching method using a specific aqueous composition for etching and a method for manufacturing a semiconductor substrate. Background Art

[0002] In the formation of wirings on a semiconductor substrate, etching solutions for etching a layer containing copper, a copper alloy, etc. are known (for example, Patent Documents 1 and 2).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: International Publication No. 2017 / 188108

[0006] Patent Document 2: International Publication No. 2020 / 105605 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] When using a known etching solution, for example, the end portions mainly composed of a layer containing copper, a copper alloy, etc. of a semiconductor substrate having a bump structure are over-etched, and problems such as undercut occur. Therefore, it is necessary to provide an aqueous composition for etching capable of selectively etching a copper-containing layer and having excellent performance in suppressing undercut.

[0009] Solutions to the Problems

[0010] The present inventors conducted intensive studies on the above problems, and as a result, found that the following aqueous composition for etching can solve the above problems. The present invention provides the following aqueous composition for etching, etc.

[0011] [1] An aqueous composition, which is an aqueous composition for etching,

[0012] The aqueous composition contains an oxidizing agent, an acid, and a corrosion inhibitor,

[0013] The pH of the aqueous composition is 0 or more and 3 or less.

[0014] [2] The aqueous composition according to the above [1], which contains:

[0015] The oxidizing agent in an amount of 0.001 to 20% by mass based on the total amount of the aqueous composition,

[0016] The acid in an amount of 0.1 to 50% by mass based on the total amount of the aqueous composition,

[0017] The corrosion inhibitor in an amount of 0.00001 to 5.0% by mass based on the total amount of the aqueous composition.

[0018] [3] The aqueous composition according to the above [1], wherein the corrosion inhibitor comprises at least any one of (i) a nitrogen-containing heterocyclic compound, (ii) a cationic surfactant or a salt thereof, and (iii) an alkyl sulfate / alkyl sulfonic acid or a salt thereof.

[0019] [4] The aqueous composition according to the above [3], wherein the content of the (i) nitrogen-containing heterocyclic compound is 0.01 to 5.0% by mass based on the total amount of the aqueous composition,

[0020] the content of the (ii) cationic surfactant or a salt thereof is 0.00001 to 0.2% by mass based on the total amount of the aqueous composition, or

[0021] the content of the (iii) alkyl sulfate / alkyl sulfonic acid or a salt thereof is 0.001 to 2.0% by mass based on the total amount of the aqueous composition.

[0022] [5] The aqueous composition according to the above [3], wherein the (i) nitrogen-containing heterocyclic compound comprises at least a nitrogen-containing 5-membered ring compound.

[0023] [6] The aqueous composition according to the above [3], wherein the (ii) cationic surfactant is selected from the group consisting of at least one of an ammonium salt represented by the following formula (4) and a heteroaryl salt having a substituted or unsubstituted alkyl group having 10 to 30 carbon atoms,

[0024]

[0025] In the above formula (4),

[0026] R 6 is a substituted or unsubstituted alkyl group having 10 to 30 carbon atoms, a substituted or unsubstituted alkyl(poly)heteroalkylene group having 10 to 30 carbon atoms, or a substituted or unsubstituted aryl(poly)heteroalkylene group having 10 to 30 carbon atoms,

[0027] 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,

[0028] X - is a halide ion, a hydroxide ion, an organic sulfonate ion, a tetrafluoroborate anion, or a hexafluorophosphate anion.

[0029] [7] The aqueous composition according to [3] above, wherein the (iii) alkyl sulfate / alkyl sulfonic acid or its salt has an alkyl group with at least 6 to 30 carbon atoms.

[0030] [8] The aqueous composition according to [1] above, wherein the acid contains an inorganic acid other than nitric acid.

[0031] [9] The aqueous composition according to [8] above, wherein the acid contains at least phosphoric acid.

[0032]

[10] The aqueous composition according to [1] above, wherein the oxidizing agent contains at least hydrogen peroxide.

[0033]

[11] An etching method, which includes the following steps: etching the seed layer of a semiconductor substrate having a seed layer containing copper with the aqueous composition according to any one of [1] to

[10] above.

[0034]

[12] The etching method according to

[11] above, wherein the semiconductor substrate further has: a layer that is laminated in contact with the seed layer and contains a metal with a greater ionization tendency than copper.

[0035]

[13] A method for manufacturing a semiconductor substrate, which includes the following steps: etching the seed layer of a semiconductor substrate having a seed layer containing copper with the aqueous composition according to any one of [1] to

[10] above.

[0036]

[14] The method for manufacturing a semiconductor substrate according to

[13] above, wherein the semiconductor substrate further has: a layer that is laminated in contact with the seed layer and contains a metal with a greater ionization tendency than copper.

[0037] Effects of the Invention

[0038] According to the present invention, an aqueous composition can be provided that selectively etches a layer containing copper, copper alloy, etc., and has an excellent effect of suppressing undercut. And according to the present invention, an etching method and a method for manufacturing a semiconductor substrate using the aqueous composition can be provided. Description of the Drawings

[0039] Figure 1 It is a schematic diagram showing the side of the semiconductor substrate before the etching treatment for evaluation in the examples and comparative examples.

[0040] Figure 2 It is shown Figure 1 A partially enlarged schematic diagram of the semiconductor substrate.

[0041] Figure 3 It is a diagram schematically showing the amount of undercut generated by the etching treatment in the examples and comparative examples. DETAILED DESCRIPTION

[0042] The aqueous etching composition and the like of the present invention will be specifically described below, but the present invention is not limited thereto and various modifications are possible without departing from the gist of the present invention.

[0043] <1. Aqueous composition for etching>

[0044] The aqueous composition of the present invention contains at least an oxidant, an acid, and a corrosion inhibitor, and the pH of the aqueous composition is 0 to 3. The aqueous composition preferably contains 0.001 to 20% by mass of the oxidant based on the total amount of the aqueous composition, 0.1 to 50% by mass of the acid based on the total amount of the aqueous composition, and 0.00001 to 5.0% by mass of the corrosion inhibitor based on the total amount of the aqueous composition.

[0045] According to a preferred embodiment of the present invention, for the aqueous composition of the present invention, as a wiring material, when comprising one or more selected from the group consisting of nickel and nickel alloys and comprising one or more selected from the group consisting of tin, tin alloys, gold and gold alloys, it is possible to selectively etch copper and copper alloys while suppressing the dissolution of these metals. It should be noted that the so-called "nickel alloy" in this specification is not particularly limited as long as one or more metal elements or non-metallic elements are added to nickel and have the properties of a metal. The same is true for "tin alloy", "gold alloy" and "copper alloy".

[0046] Examples of the objects to be etched using the aqueous composition of the present invention include: a laminate preferably comprising a layer mainly composed of copper and a layer mainly composed of nickel or a nickel alloy; a laminate comprising a layer mainly composed of copper, a layer mainly composed of nickel or a nickel alloy, and a layer mainly composed of tin, a tin alloy, gold or a gold alloy, etc.

[0047] [1-1. Components of aqueous etching composition]

[0048] Hereinafter, each component contained in the aqueous composition of the present invention will be described in detail.

[0049] 1-1(A) Oxidant

[0050] The oxidizing agent is mainly a component that oxidizes copper. Examples of the oxidizing agent include peroxyacids, halogen oxygen-containing acids, and salts thereof. Examples of the aforementioned peroxyacids include hydrogen peroxide, persulfuric acid, percarbonic acid, perphosphoric acid, peracetic acid, perbenzoic acid, and meta-chloroperbenzoic acid. Examples of the aforementioned halogen oxygen-containing acids include chlorine oxygen-containing acids such as hypochlorous acid, chlorous acid, chloric acid, and perchloric acid; bromine oxygen-containing acids such as hypobromous acid, bromous acid, bromic acid, and perbromic acid; iodine oxygen-containing acids such as hypoiodous acid, iodous acid, iodic acid, and periodic acid; and the like. As the above-mentioned salt, alkali metal salts such as lithium salts, sodium salts, potassium salts, rubidium salts, and cesium salts of the above-mentioned peroxyacids or halogen-containing acids; alkaline earth metal salts such as beryllium salts, magnesium salts, calcium salts, strontium salts, and barium salts of the above-mentioned peroxyacids or halogen-containing acids; metal salts such as aluminum salts, copper salts, zinc salts, and silver salts of the above-mentioned peroxyacids or halogen-containing acids; ammonium salts of the above-mentioned peroxyacids or halogen-containing acids, etc. Among these oxidants, hydrogen peroxide is preferred. In general, considering the viewpoints of availability and operability, it is preferred to use an aqueous solution of hydrogen peroxide as an oxidant.

[0051] The concentration of the oxidant in the aqueous composition is preferably 0.001 to 20% by mass, more preferably 0.1 to 10.0% by mass, further preferably 0.02 to 5.0% by mass, particularly preferably 0.1 to 3% by mass, 0.5 to 2.0% by mass, or 0.5 to 1.5% by mass, relative to the total mass of the aqueous composition. By adjusting the concentration of the oxidant to such an aqueous composition, a good etching rate can be achieved, and unnecessary dissolution of the wiring material can be suppressed.

[0052] 1-1(B) Acid

[0053] The acid in the aqueous composition mainly acts as an etchant for copper and copper alloys oxidized by the oxidant. Phosphoric acid (H 3 PO 4 ), phosphonic acid (H 3 PO 3 ), pyrophosphate (H 4 P 2 O 7 ), metaphosphoric acid (HPO 3 ) and other phosphoric acids; sulfuric acid, hydrochloric acid, hydrofluoric acid, hydrobromic acid, hydroiodic acid, nitric acid, etc. Among these acids, phosphoric acids are preferably used, and phosphoric acid is particularly preferably used.

[0054] In addition, etching equipment exposed to nitric acid for a long period of time may also be corroded, and therefore it is preferable to use an inorganic acid other than nitric acid and nitrous acid, or to use an inorganic acid excluding at least nitric acid as the acid component.

[0055] The acid in the aqueous composition preferably contains 50% or more of phosphoric acids or phosphoric acid, based on the total mass of the acid, more preferably contains 70% or more of phosphoric acids or phosphoric acid, further preferably contains 90% or more of phosphoric acids or phosphoric acid, and it is particularly preferred to use only phosphoric acids or phosphoric acid as the acid.

[0056] The concentration of the acid in the aqueous composition is preferably 0.1 to 50% by mass, more preferably 1.0 to 30% by mass, further preferably 3.0 to 20% by mass, and particularly preferably 5.0 to 10% by mass. If the concentration of the acid is adjusted to an aqueous composition within the above range, the aqueous composition will have a good etching rate and can suppress unnecessary dissolution of the wiring material.

[0057] 1-1(C) Corrosion Inhibitors

[0058] The corrosion inhibitor in the aqueous composition can effectively inhibit corrosion of a layer containing a metal such as nickel having a greater ionization tendency than copper by reacting with the surface of copper, nickel, etc. or adsorbing on the surface, and can effectively inhibit contact corrosion in particular, and can also inhibit excessive etching, i.e., side corrosion, of a layer containing copper, etc. The corrosion inhibitor preferably contains at least any one of (i) a nitrogen-containing heterocyclic compound, (ii) a cationic surfactant, and (iii) an alkyl sulfuric acid / alkyl sulfonic acid or a salt thereof.

[0059] The total concentration of the corrosion inhibitor in the aqueous composition is preferably 0.00001 to 5.0 mass %, more preferably 0.0001 to 3.0 mass %, further preferably 0.0005 to 1.0 mass %, and particularly preferably 0.001 to 0.2 mass %, based on the total amount of the aqueous composition. When the concentration of the corrosion inhibitor is adjusted to the aqueous composition within the above range, the corrosion of the layer containing a metal such as nickel having a greater ionization tendency than copper can be effectively suppressed, especially the contact corrosion can be effectively suppressed, and the over-etching, i.e., the side etching of the layer containing copper can be suppressed.

[0060] (i) Nitrogen-containing heterocyclic compounds

[0061] The (i) nitrogen-containing heterocyclic compound preferably used as a corrosion inhibitor preferably contains 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 an alkyl group having 1 to 6 carbon atoms, an amino group, and a substituted amino group, and the substituted amino group has one or more substituents selected from the group consisting of an alkyl group having 1 to 6 carbon atoms and a phenyl group. In addition, the nitrogen-containing heterocyclic compound may also contain a ring other than the nitrogen-containing 5-membered ring, such as an aliphatic ring having 5 to 30 carbon atoms, an aromatic ring having 6 to 30 carbon atoms, etc., and these rings may also be condensed rings with the nitrogen-containing 5-membered ring. For example, the nitrogen-containing 5-membered ring compound is one or more selected from the group consisting of pyrrole, pyrazole, imidazole, triazole, and tetrazole. The nitrogen-containing 5-membered ring compound may be only one kind or a combination of two or more kinds.

[0062] Examples of the nitrogen-containing five-membered ring compound include compounds represented by the following formula (1), formula (2) or formula (3):

[0063]

[0064] [In formula (1) to formula (3), R 1 , R 2 , R 3 , R 4 and R 5 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,

[0065] R 2 With 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,

[0066] R 4 With R 5 They 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.]

[0067] 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.

[0068] As the alkyl group having 1 to 6 carbon atoms, linear or branched alkyl groups and cycloalkyl groups can be cited. As the linear or branched alkyl group, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, etc. can be cited. As the cycloalkyl group, cycloalkyl groups having 3 to 6 carbon atoms can be cited, for example, cyclopropyl, cyclopentyl, cyclohexyl, etc. can be cited. Among these, methyl or ethyl is preferred, and methyl is particularly preferred.

[0069] The substituted amino group is not particularly limited as long as it is an 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. The alkyl group having 1 to 6 carbon atoms is as described above.

[0070] Preferred specific examples of nitrogen-containing 5-membered ring compounds include 5-methyltetrazole, 5-aminotetrazole, 1,2,4-triazole, 1,2,3-triazole, and tetrazole. Among these, one or more selected from the group consisting of 1,2,4-triazole, 3-amino-1,2,4-triazole, 5-methyltetrazole, and 5-aminotetrazole are particularly preferred.

[0071] In addition to the compounds represented by the above formulae (1) to (3), pyrrole, pyrazole, and compounds containing the above R in their ring skeletons are also preferred. 1 ~R 5 Compounds having the substituents shown.

[0072] In addition, as (i) nitrogen-containing heterocyclic compounds, compounds other than nitrogen-containing 5-membered ring compounds are preferred. For example, as nitrogen-containing 6-membered ring compounds, pyridine, pyrazine, pyrimidine, pyridazine, triazine, tetrazine, pentazine, hexazine, and the ring skeletons of these compounds containing the above R 1 ~R 5 Compounds having the substituents shown.

[0073] (i) The nitrogen-containing heterocyclic compound may be used alone or in combination of two or more.

[0074] The concentration of the (i) nitrogen-containing heterocyclic compound in the aqueous composition is, for example, 0.0001 to 5.0% by mass, preferably 0.01 to 5.0% by mass, more preferably 0.05 to 2.0% by mass, further preferably 0.07 to 1.0% by mass, and particularly preferably 0.1 to 0.5% by mass, based on the total amount of the aqueous composition.

[0075] (ii) Cationic surfactant

[0076] The (ii) cationic surfactant preferably used as the corrosion inhibitor preferably includes an alkyl-containing quaternary ammonium hydroxide or a salt thereof, and an alkyl-containing heteroaryl hydroxide or a salt thereof.

[0077] Preferred specific examples of the alkyl-containing ammonium hydroxide or its salt are represented by the following formula (4).

[0078]

[0079] In the above formula (4), R 6It 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.

[0080] The alkyl group having 4 to 30 carbon atoms is not particularly limited, and examples thereof include butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, docosyl, tetracosyl, hexacosyl, octacosyl, and triacontyl.

[0081] When a substituted or unsubstituted alkyl group having 4 to 30 carbon atoms has a substituent (substituted alkyl group having 4 to 30 carbon atoms), the substituent is not particularly limited, and examples thereof include halogen atoms such as fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms; 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; nitro groups, and the like. It should be noted that the number of substituents may be one, or two or more. Furthermore, a substituted alkyl group having 4 to 30 carbon atoms means that the total number of carbon atoms of the substituent group and the alkyl group is 4 to 30. That is, in order to make the total number of carbon atoms of the substituent group fall within the above range, an alkyl group having 4 or more carbon atoms (for example, an alkyl group having 4 to 13 carbon atoms such as butyl, hexyl, octyl, decyl, and dodecyl) may be included.

[0082] The alkyl (poly) heteroalkylene group having 4 to 30 carbon atoms is composed of -(C n H 2n -Z-) m -R 3 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), and is preferably an oxygen atom (O). R 7 The alkyl group having 1 to 30 carbon atoms includes methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and eicosyl.

[0083] 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 group is not particularly limited, and examples thereof include halogen atoms such as fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms; 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; nitro groups, etc. It should be noted that the substituent group usually replaces R 7hydrogen atom. Moreover, the substituent may be 1 or may have 2 or more. Furthermore, a substituted alkyl (poly) heteroalkylene group having 4 to 30 carbon atoms means that the total number of carbon atoms of the substituent group and the alkyl (poly) heteroalkylene group is 4 to 30. That is, in order to make the total number of carbon atoms of the substituent group fall within the above range, the substituted alkyl (poly) heteroalkylene group having 4 to 30 carbon atoms may include an alkyl (poly) heteroalkylene group having 4 or more carbon atoms (for example, a group having an alkyl group having 4 to 13 carbon atoms such as butyl, hexyl, octyl, decyl, and dodecyl).

[0084] The aryl (poly) heteroalkylene group having 4 to 30 carbon atoms is composed of -(C n H 2n -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 is an aryl group having 6 to 18 carbon atoms, and examples thereof include phenyl, naphthyl, anthracenyl, and the like.

[0085] When the substituted or unsubstituted aryl (poly) heteroalkylene group having 4 to 30 carbon atoms has a substituent (substituted aryl (poly) heteroalkylene group having 4 to 30 carbon atoms), the substituent is not particularly limited, and examples thereof include halogen atoms such as fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms; 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 propoxy; hydroxyl; cyano; nitro, and the like. It should be noted that the substituent group usually replaces the hydrogen atom of Ar. In addition, the substituent group may be one or may have two or more. Furthermore, the substituted aryl (poly) heteroalkylene group having 4 to 30 carbon atoms means that the total number of carbon atoms of the substituent group and the number of carbon atoms of the aryl (poly) heteroalkylene group is 4 to 30. That is, in the substituted aryl (poly) heteroalkylene group having 4 to 30 carbon atoms, in order to make the total carbon number of the substituents fall within the above range, an aryl (poly) heteroalkylene group having 4 or more carbon atoms (for example, a group having an alkyl group having 4 to 13 carbon atoms such as butyl, hexyl, octyl, decyl, and dodecyl) may be included.

[0086] In one embodiment, R 6 It 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, further 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 p-(1,1,3,3-tetramethylbutyl)phenylbis(oxyethylene) (p-CH3 C(CH 3 ) 2 CH 2 C(CH 3 ) 2 -Ph-(OC 2 H 4 ) 2 -)base.

[0087] In another embodiment, R 6 Preferably, it is 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 further preferably, it is dodecyl, tetradecyl, hexadecyl, octadecyl, p-(1,1,3,3-tetramethylbutyl)phenylbis(oxyethylene) (p-CH 3 C(CH 3 ) 2 CH 2 C(CH 3 ) 2 -Ph-(OC 2 H 4 ) 2 -) group, particularly preferably hexadecyl, octadecyl, p-(1,1,3,3-tetramethylbutyl)phenylbis(oxyethylene) (p-CH 3 C(CH 3 ) 2 CH 2 C(CH 3 ) 2 -Ph-(OC 2 H 4 ) 2 -) group, most preferably p-(1,1,3,3-tetramethylbutyl)phenylbis(oxyethylene) (p-CH 3 C(CH 3 ) 2 CH 2 C(CH 3 ) 2 -Ph-(OC 2 H 4 ) 2 -)base.

[0088] In addition, R 7 Each 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.

[0089] The alkyl group having 1 to 30 carbon atoms is not particularly limited, and examples thereof include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, nonadecyl, and eicosyl.

[0090] When a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms has a substituent (substituted alkyl group having 1 to 30 carbon atoms), the substituent includes halogen atoms such as fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms; 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; cyano; nitro, etc. It should be noted that the substituent may be 1 or may have 2 or more. In addition, 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.

[0091] The aryl group having 6 to 30 carbon atoms is not particularly limited, and examples thereof include phenyl, naphthyl, and biphenyl.

[0092] When a substituted or unsubstituted aryl group having 6 to 30 carbon atoms has a substituent (substituted aryl group having 6 to 30 carbon atoms), the substituent includes halogen atoms such as fluorine atoms, chlorine atoms, bromine atoms, 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 propoxy; hydroxyl; cyano; nitro, etc. It should be noted that the substituent may be 1 or may have 2 or more. In addition, a substituted aryl group having 6 to 30 carbon atoms means that the total number of carbon atoms of the substituent and the number of carbon atoms of the alkyl group is 6 to 30.

[0093] Among these, R 7 Preferably, it is a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, more preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, a hexyl group, an octyl group, a decyl group, a dodecyl group, a tetradecyl group, a hexadecyl group, an octadecyl group, a benzyl group, a hydroxymethyl group, or a 2-hydroxyethyl group, further preferably a methyl group, an ethyl group, a benzyl group, or a 2-hydroxyethyl group, particularly preferably a methyl group or a benzyl group, and most preferably a methyl group. In another embodiment, R 7 It is preferably an alkyl group having 1 to 10 carbon atoms substituted by an aryl group having 6 to 20 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms substituted by a phenyl group, further preferably a benzyl group or a phenylethyl group, and particularly preferably a benzyl group.

[0094] X is a halide ion (fluoride ion, chloride ion, bromide ion, iodide ion, etc.), a hydroxide ion, an organic sulfonate ion (methanesulfonate ion, p-toluenesulfonate ion, etc.), a tetrafluoroborate anion, or a hexafluorophosphate anion. Among these, X is preferably a halide ion, and more preferably a chloride ion or a bromide ion.

[0095] As R6 Specific examples of the ammonium salt represented by the formula (1) 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; and ammonium salts having a tetradecyltrimethylammonium bromide. , benzyldimethyltetradecylammonium chloride and the like ammonium salts having a tetradecyl group; hexadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium p-toluenesulfonate, hexadecyltrimethylammonium hydroxide, ethylhexadecyldimethylammonium chloride, ethylhexadecyldimethylammonium bromide, benzyldimethylhexadecylammonium chloride and the like ammonium salts having a hexadecyl group; trimethyloctadecylammonium chloride, trimethyloctadecylammonium bromide, dimethyldioctadecylammonium chloride, dimethyldioctadecylammonium bromide, benzyldimethyloctadecylammonium chloride and the like ammonium salts having an octadecyl group.

[0096] As R 6 Specific examples of the ammonium salt represented by the formula (1) which is a substituted or unsubstituted alkyl (poly) heteroalkylene group having 4 to 30 carbon atoms include trimethylpropyldi(oxyethylene)ammonium chloride and trimethylpropyloxyethylenethioethyleneammonium chloride.

[0097] As R 6 Specific examples of the ammonium salt represented by the formula (1) 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.

[0098] In one embodiment, regarding the ammonium salt represented by the above formula (1), R 6 is a substituted or unsubstituted aryl (poly) heteroalkylene group having 4 to 30 carbon atoms, R 7 At least one of them is a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, and more preferably R 6 is a substituted or unsubstituted aryl (poly) heteroalkylene group having 8 to 20 carbon atoms, R 7 At least one of them is a substituted or unsubstituted aryl group having 6 to 15 carbon atoms, and more preferably R 6 is a substituted or unsubstituted aryl (poly) heteroalkylene group having 10 to 18 carbon atoms, R 7 At least one of the aryl groups is a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, and benzyldimethyl-2-{2-[4-(1,1,3,3-tetramethylbutyl)phenoxy]ethoxy}ethylammonium chloride (benzethonium chloride) is particularly preferred.

[0099] Furthermore, the heteroaryl salt having a substituted or unsubstituted alkyl group having 4 to 30 carbon atoms is not particularly limited, and examples thereof include salts of heteroaryl cations in which at least one nitrogen atom of a substituted or unsubstituted nitrogen atom-containing heteroaryl ring is bonded to a substituted or unsubstituted alkyl group having 4 to 30 carbon atoms.

[0100] The nitrogen atom-containing heteroaryl ring is not particularly limited, and examples thereof include rings of imidazole, pyrazole, oxazole, isoxazole, thiazole, isothiazole, pyridine, pyrazine, pyridazine, pyrimidine, quinoline, and isoquinoline.

[0101] At this time, when the nitrogen-containing heteroaryl ring has a substituent, examples of the substituent include halogen atoms such as fluorine, chlorine, bromine, and iodine atoms; 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; cyano; nitro, and the like.

[0102] The alkyl group having 4 to 30 carbon atoms is not particularly limited, and examples thereof include butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, docosyl, tetracosyl, hexacosyl, octacosyl, and triacontyl.

[0103] When a substituted or unsubstituted alkyl group having 4 to 30 carbon atoms has a substituent (substituted alkyl group having 4 to 30 carbon atoms), the substituent includes halogen atoms such as fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms; 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; cyano; nitro, etc. It should be noted that the substituent may be one or may have two or more. In addition, a substituted alkyl group having 4 to 30 carbon atoms means that the total number of carbon atoms of the substituent and the alkyl group is 4 to 30. That is, in order to make the total number of carbon atoms of the substituents fall within the above range, 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 butyl, hexyl, octyl, decyl, and dodecyl).

[0104] Among 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, further preferably dodecyl, tetradecyl, hexadecyl, and octadecyl, and particularly preferably dodecyl, tetradecyl, and hexadecyl groups are considered to be able to suppress side etching.

[0105] The counter anion of the 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; hexafluorophosphate anion, etc. Among these, the counter anion is preferably a halide ion, and more preferably a chloride ion or a bromide ion.

[0106] Specific examples of the heteroaryl salt 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-methylimidazolium chloride, 1-dodecyl-3-methylimidazolium bromide, 1-tetradecyl-3-methylimidazolium chloride, 1-tetradecyl-3-methylimidazolium bromide, imidazolium salts such as 3-methylimidazolium bromide, 1-hexadecyl-3-methylimidazolium chloride, 1-hexadecyl-3-methylimidazolium bromide, 1-octadecyl-3-methylimidazolium chloride, and 1-octadecyl-3-methylimidazolium bromide; oxazolium salts such as 3-butyloxazolium chloride, 3-hexyloxazolium chloride, 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-decyl Thiazolium chloride, 3-dodecylthiazolium chloride, 3-tetradecylthiazolium chloride, 3-hexadecylthiazolium chloride, 3-octadecylthiazolium chloride and the like thiazolium salts; 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 the like pyridinium salts; 1-butylpyrimidinium chloride, 1-hexylpyrimidinium chloride, 1 Pyrimidinium salts such as 1-octylpyrimidinium chloride, 1-decylpyrimidinium chloride, 1-dodecylpyrimidinium chloride, 1-tetradecylpyrimidinium chloride, 1-hexadecylpyrimidinium chloride, and 1-octadecylpyrimidinium chloride; quinolinium salts such as butylquinolinium chloride, hexylquinolinium chloride, octylquinolinium chloride, decylquinolinium chloride, dodecylquinolinium chloride, tetradecylquinolinium chloride, hexadecylquinolinium chloride, and octadecylquinolinium chloride; isoquinolinium salts such as decylisoquinolinium chloride, dodecylisoquinolinium chloride, tetradecylisoquinolinium chloride, hexadecylisoquinolinium chloride, and octadecylisoquinolinium chloride. Furthermore, these may also be used as hydrates.

[0107] Among these, the cationic surfactant (ii) is preferably an ammonium salt represented by formula (4) (where R 6is 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, a pyridinium salt having a substituted or unsubstituted alkyl group having 8 to 20 carbon atoms, and more preferably 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, 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, a pyridinium salt having a substituted or unsubstituted alkyl group having 10 to 18 carbon atoms, and more preferably 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, R 7 at least one of which is 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, a pyridinium salt having a substituted or unsubstituted alkyl group having 12 to 18 carbon atoms, and particularly preferably 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, R 7 at least one of which is a substituted or unsubstituted aryl group having 6 to 12 carbon atoms), a pyridinium salt having a substituted or unsubstituted alkyl group having 12 to 16 carbon atoms, and most preferably benzethonium chloride and benzethonium bromide.

[0108] It should be noted that the above-mentioned (ii) cationic surfactant or its salt may be used alone or in combination of two or more thereof. That is, in a preferred embodiment, (ii) cationic surfactant or its salt preferably comprises an ammonium salt selected from the group consisting of: 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 more preferably contains at least one selected from the group consisting of an ammonium salt represented by the formula (4) (wherein, R 6 is a substituted or unsubstituted aryl (poly) heteroalkylene group having 16 to 20 carbon atoms, R 7 at least one of the group consisting of an imidazolium salt having a substituted or unsubstituted alkyl group having 10 to 16 carbon atoms, and a pyridinium salt having a substituted or unsubstituted alkyl group having 10 to 16 carbon atoms, and more preferably an ammonium salt selected from the group consisting of: 6 is a substituted or unsubstituted aryl (poly) heteroalkylene group having 18 to 20 carbon atoms, R 7At least one of the group consisting of 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, and particularly preferably an ammonium salt selected from the group consisting of an ammonium salt represented by the formula (4) (wherein R 6 is a substituted or unsubstituted aryl (poly) heteroalkylene group having 18 to 20 carbon atoms, R 7 At least one of which is a substituted or unsubstituted aryl group having 6 to 12 carbon atoms), and at least one of the group consisting of a pyridinium salt having a substituted or unsubstituted alkyl group having 10 to 14 carbon atoms, and most preferably at least one selected from the group consisting of benzethonium chloride and benzethonium bromide.

[0109] Preferred specific examples of the cationic surfactant (ii) include dodecylpyridinium chloride, benzyldimethylhexadecylammonium chloride, benzethonium chloride, 1-hexadecyl-3-methylimidazolium chloride, octyltrimethylammonium chloride, etc. The cationic surfactant (ii) may be used alone or in combination of two or more.

[0110] The concentration of the (ii) cationic surfactant or its salt 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 %, further preferably 0.0007 to 0.03 mass %, particularly preferably 0.001 to 0.01 mass %, based on the total amount of the aqueous composition.

[0111] (iii) Alkyl sulfuric acid / alkyl sulfonic acid or its salt

[0112] The type of (iii) alkylsulfonic acid or its salt (hereinafter also referred to as alkylsulfonic acid, etc.) in the aqueous composition is not particularly limited, but the aqueous composition preferably contains at least alkylsulfonic acid, etc. having an alkyl group with 6 to 30 carbon atoms.

[0113] (iii) Alkylsulfuric acid / alkylsulfonic acid etc. may have an aryl group having 6 to 20 carbon atoms, preferably an alkyl group having 8 to 20 carbon atoms and / or an aryl group having 6 to 16 carbon atoms, more preferably an alkyl group having 10 to 16 carbon atoms and / or an aryl group having 6 to 12 carbon atoms.

[0114] Preferred specific examples of (iii) alkyl sulfuric acid / alkyl sulfonic acid or its salt include dodecyl sulfuric acid, sodium dodecyl sulfate, ammonium dodecyl sulfate, dodecylbenzenesulfonic acid such as 4-dodecylbenzenesulfonic acid, sodium dodecylbenzenesulfonate, ammonium dodecylbenzenesulfonate, etc. (iii) alkyl sulfuric acid / alkyl sulfonic acid may be used alone or in combination of two or more.

[0115] The concentration of (iii) alkyl sulfuric acid / alkyl sulfonic acid etc. in the aqueous composition is, for example, 0.001 to 2.0% by mass, preferably 0.002 to 1.0% by mass, more preferably 0.005 to 0.5% by mass, further preferably 0.007 to 0.05% by mass, further preferably 0.007 to 0.03% by mass, particularly preferably 0.008 to 0.02% by mass, based on the total amount of the aqueous composition.

[0116] (D) Additives

[0117] The aqueous composition may contain, as additive (D), a hydrogen peroxide stabilizer, an organic solvent, a surfactant other than a cationic surfactant and an alkylsulfonic acid / alkylsulfonic acid or a salt thereof, a chelating agent, a defoaming agent, an acid other than (B), a base, a silicon-containing compound, etc. In particular, as a hydrogen peroxide stabilizer, a known compound such as alcohols, urea, phenylurea, organic carboxylic acids, organic phosphonic acids, and organic phosphoric acids may be appropriately added.

[0118] [Other ingredients]

[0119] The aqueous composition of the present invention may contain, in addition to the above-mentioned components, water and, if necessary, one or more of various additives generally used in aqueous compositions, within a range not impairing the effects of the aqueous composition of the present invention.

[0120] As water, water from which metal ions, organic impurities, particles, etc. have been removed by distillation, ion exchange treatment, filtration treatment, various adsorption treatments, etc. is preferred, pure water is more preferred, and ultrapure water is particularly preferred. The content of water in the aqueous composition can be appropriately adjusted according to the content of other components in the aqueous composition, etc., and is not particularly limited. The content of the water is, for example, 70 to 99% by mass, preferably 75 to 98% by mass, and more preferably 85 to 95% by mass, relative to the total mass of the aqueous composition.

[0121] The aqueous composition is preferably a dissolving liquid, and preferably does not contain solid particles such as abrasive particles.

[0122] In the aqueous composition, the total content of the oxidizing agent of component (A), the acid of component (B), the corrosion inhibitor of component (C) and water, or the total content of the additive further including component (D), is preferably 70 to 100% by mass, more preferably 85 to 100% by mass, further preferably 90 to 100% by mass, and particularly preferably 95 to 100% by mass, relative to the total mass of the aqueous composition.

[0123] [1-2. Properties and performance of aqueous etching composition]

[0124] The pH value in the aqueous composition is in the range of 0.0 to 3.0, and the pH value is preferably 0.3 to 3.0, more preferably 0.5 to 2.0, further preferably 0.7 to 1.8, and particularly preferably 0.7 to 1.4.

[0125] The aqueous composition exhibits an excellent side corrosion inhibition effect. Specifically, for the lower side of the plating layer containing a metal having an ionization tendency greater than copper, such as nickel, or a nickel alloy, i.e., a seed layer formed on the substrate side, which contains copper or a copper alloy, for example, a seed layer substantially formed of a copper alloy, side corrosion mainly caused by excessive etching of the end portion can be effectively prevented. Specifically, in the measurement method described later, the side corrosion can be suppressed to 1.5 μm or less, more preferably to 1.0 μm or less, and further preferably to 0.7 μm or less.

[0126] [1-3. Preparation of aqueous composition]

[0127] The aqueous composition can be prepared by uniformly stirring component (A), component (B), component (C), component (D) and water, and further other components as required. The stirring method of these components is not particularly limited, and a stirring method commonly used in the preparation of an aqueous composition can be adopted.

[0128] [1-4. Use of aqueous composition]

[0129] The aqueous composition can be used for etching copper and copper alloys. In particular, in the packaging applications of the new generation of DRAM memory, NAND memory, etc., when the material for the process using bumps contains one or more selected from the group consisting of nickel and nickel alloys and optionally one or more selected from the group consisting of tin, tin alloys, gold and gold alloys, it can be suitably used as an aqueous composition that inhibits the dissolution of these metals and selectively etches at least one selected from copper and copper alloys.

[0130] <2. Etching method>

[0131] The etching method of the present invention is a method mainly for semiconductor substrates, and includes the following steps: using the aqueous composition to etch the seed layer of an intermediate product having a seed layer of a semiconductor substrate containing copper. The semiconductor substrate to be etched by the etching method preferably has a layer on the upper side of the seed layer that is stacked in contact with the seed layer and contains a metal with a greater ionization tendency than copper.

[0132] The use temperature of the aqueous composition in the etching process is not particularly limited, and is preferably a temperature of 10 to 50°C, more preferably 20 to 45°C, and further preferably 25 to 40°C. If the temperature of the aqueous composition is above 10°C, the etching rate will be good, so excellent production efficiency can be obtained. On the other hand, if the temperature of the aqueous composition is below 50°C, the liquid composition change will be suppressed, and the etching conditions can be kept fixed. The etching rate will increase by increasing the temperature of the aqueous composition, but the optimal processing temperature can be appropriately determined based on the consideration of suppressing the composition change of the aqueous composition (decomposition of hydrogen peroxide) to a small extent.

[0133] In addition, the etching treatment time is not particularly limited, preferably 10 to 600 seconds, more preferably 30 to 120 seconds. The treatment time can be appropriately selected according to various conditions such as the surface state of the etching object, the concentration of the aqueous composition, the temperature and the treatment method. For example, in the etching treatment of a seed layer formed by a copper alloy or the like stacked immediately below a plating layer whose main component is a metal such as nickel with a greater ionization tendency than copper, the time until the color of the seed layer disappears and only remains in the area overlapping with the plating layer (appropriate etching time (also called JET)) is used as the treatment time.

[0134] There is no particular limitation on the method of contacting the aqueous composition with the etching object. For example, the aqueous composition may be contacted with the etching object in the form of dripping (single-wafer spinning process) or spraying, or a wet etching method such as a method of impregnating the etching object with the aqueous composition. In the present invention, any method may be used.

[0135] <3. Method for manufacturing semiconductor substrate>

[0136] The method for manufacturing a semiconductor substrate of the present invention includes at least the above-mentioned etching step. Furthermore, the method for manufacturing a semiconductor substrate may include the following step.

[0137] That is, the following steps may be included:

[0138] A step of preparing a semiconductor substrate having a surface thereof having a copper seed layer including one or more selected from the group consisting of copper and copper alloys;

[0139] forming a resist pattern having an opening pattern exposing a portion of the copper seed layer;

[0140] A step of forming a metal layer A and a metal layer B in this order, the metal layer A comprising one or more selected from the group consisting of nickel and a nickel alloy, and the metal layer B comprising one or more selected from the group consisting of tin, a tin alloy, gold, and a gold alloy, on the surface of the copper seed layer exposed in the opening portion of the opening pattern of the resist pattern; and

[0141] Step of removing the above-mentioned resist pattern.

[0142] Moreover, in the method for manufacturing a semiconductor substrate, it is necessary to include: a step of bringing the exposed portion of the copper seed layer where the metal layer A and the metal layer B are not formed, which is generated in the step of removing the above-mentioned resist pattern, into contact with the aqueous composition and etching the exposed portion of the copper seed layer.

[0143] Examples

[0144] Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

[0145] [Example 1]

[0146] By adding (A) hydrogen peroxide (H 2 O 2 ), (B) phosphoric acid as an inorganic acid, and (C) corrosion inhibitor 1,2,4-triazole to pure water and stirring, a cleaning composition for a semiconductor substrate was produced. At this time, the addition rates of hydrogen peroxide, phosphoric acid, and 1,2,4-triazole were 0.75% by mass, 8% by mass, and 0.2% by mass, respectively, with respect to the total mass of the cleaning composition for a semiconductor substrate. In addition, the pH of the cleaning composition for a semiconductor substrate was 0.9. Regarding the pH, the pH of the pretreatment agent at 23°C was measured using a bench-type pH meter (F-71) and a pH electrode (9615S-10D) manufactured by Horiba, Ltd.

[0147] [Examples 2 to 13, Comparative Example 1, and Reference Example 1]

[0148] Except for changing to the added components and the like as shown in Table 1 below, the aqueous compositions in Examples 2 to 13, Comparative Example 1, and Reference Example 1 were produced in the same manner as in Example 1.

[0149] [Table 1]

[0150]

[0151] [Evaluation Method]

[0152] The Cu J.E.T (Just Etching Time) and the Cu side etching amount of the cleaning compositions for a semiconductor substrate produced in Examples 1 to 13, Comparative Example 1, and Reference Example 1 were evaluated.

[0153] (Samples for Evaluation)

[0154] In each of the examples, comparative examples, etc., those having Figure 1A semiconductor substrate 10 having a structure of is used as an evaluation substrate. The semiconductor substrate 10 includes an upper SnAg layer 14, a Ni layer 16 stacked below the SnAg layer 14, and a Cu layer 12 stacked below the Ni layer 16. Furthermore, in the semiconductor substrate 10, a Ti layer 18 is stacked on the lower side of the Cu layer 12, and the Ti layer 18 is provided above the substrate 20.

[0155] In the embodiments and comparative examples, Figure 1 and Figure 1 The enlarged image of the area enclosed by the dotted quadrilateral Figure 2 As shown, 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. It should be noted that Figure 1 The cylindrical bumps shown have a diameter of 12.5 μm and a height of 9 μm.

[0156] (Evaluation of JET in Etching of Cu Layer)

[0157] The evaluation samples were cut into 1 cm × 1 cm pieces (impregnation treatment area: 1 cm 2 ) size. Then, in 50 g of the aqueous composition for etching a semiconductor substrate prepared in Examples 1 to 13, Comparative Example 1 and Reference Example 1, the evaluation sample was impregnated at 25° C. for a predetermined time while being stirred at 350 rpm with a stirrer. During the impregnation treatment, the evaluation sample was held with tweezers and impregnated in a state where it was located on the stirrer.

[0158] When evaluating sample impregnation, the following time was defined as Cu JET and measured: the time from the start of impregnation (etching treatment) to the time required for the color of the substrate surface to change from orange to silver by visual observation, that is, the time required until it can be judged that the color of the seed layer disappears and only remains in the area overlapping with the plating layer.

[0159] (Cu side erosion amount)

[0160] In the semiconductor substrate etching compositions manufactured in Examples 1 to 13, Comparative Example 1, and Reference Example 1, an evaluation sample was subjected to an infiltration treatment while being stirred with a magnetic stirrer at 350 rpm for 1.5 times the Cu J.E.T. time at 25°C. In a FIB (focused ion beam) apparatus (Helios G4 UX (manufactured by Thermo scientific)), the processed evaluation sample was processed in such a manner that a circle became a semi-circle when observing the bump from above. Then, an SEM image of the processed evaluation sample was obtained using Helios G4 UX (manufactured by Thermo scientific). In the SEM image, the distance in the horizontal direction from the Ni end face to the Cu end face was defined as the Cu undercut amount and measured.

[0161] As shown in Table 1, it was confirmed that in the case of using the aqueous compositions of Examples 1 to 13, corrosion of nickel and the tin - silver alloy was inhibited, and copper was selectively etched.

[0162] On the other hand, in Comparative Example 1 and the like, in which the composition group deviated from the range defined in the present invention, since contact corrosion occurred in the nickel plating layer 16 (refer to Figure 2 and Figure 3 ), the undercut amount of the Cu layer 12 increased.

[0163] That is, as schematically shown in Figure 3 (a), in the intermediate 10a of the semiconductor substrate of the example, contact corrosion in the end region below the lower metal layer (plating) 16a was prevented, and undercut at the end of the Cu seed layer 12a was suppressed. In contrast, as shown in Figure 3 (b), in the intermediate 10b of the semiconductor substrate of the comparative example, contact corrosion occurred in the end region below the lower metal layer (plating) 16b, and as the contact corrosion progressed, undercut at the end of the Cu seed layer 12b also expanded.

[0164] Industrial Applicability

[0165] The aqueous composition of the present invention can be preferably used for forming wirings on a semiconductor substrate. According to a preferred embodiment of the present invention, dissolution of wiring materials containing nickel, nickel alloys, etc. is inhibited, copper and copper alloys are selectively etched, and undercut of the seed layer of copper and copper alloys can be prevented.

[0166] Description of Reference Numerals

[0167] 10: Semiconductor substrate

[0168] 10a: Semiconductor substrate in the example

[0169] 10b: Semiconductor substrate in the comparative example

[0170] 12: Cu layer (seed layer)

[0171] 12a: Cu layer in the example

[0172] 12b: Cu layer in the comparative example

[0173] 14: SnAg layer (upper metal layer)

[0174] 16: Ni layer (lower metal layer)

[0175] 16a: Ni layer in the example

[0176] 16b: Ni layer in the comparative example

[0177] 18: Ti layer (barrier metal layer)

[0178] 18a: Ti layer in the example

[0179] 18b: Ti layer in the comparative example

[0180] 20: Substrate

Claims

1. An aqueous composition, which is an aqueous composition for etching, The aqueous composition contains an oxidizing agent, an acid, and a corrosion inhibitor, The pH of the aqueous composition is 0 or more and 3 or less.

2. The aqueous composition according to claim 1, which contains: The oxidizing agent in an amount of 0.001 to 20% by mass based on the total amount of the aqueous composition, The acid in an amount of 0.1 to 50% by mass based on the total amount of the aqueous composition, The corrosion inhibitor in an amount of 0.00001 to 5.0% by mass based on the total amount of the aqueous composition.

3. The aqueous composition according to claim 1, wherein, The corrosion inhibitor contains at least any one of (i) a nitrogen-containing heterocyclic compound, (ii) a cationic surfactant or its salt, and (iii) an alkyl sulfate / alkyl sulfonic acid or its salt.

4. The aqueous composition according to claim 3, wherein, The content of the (i) nitrogen-containing heterocyclic compound is 0.01 to 5.0% by mass based on the total amount of the aqueous composition, The content of the (ii) cationic surfactant or its salt is 0.00001 to 0.2% by mass based on the total amount of the aqueous composition, or The content of the (iii) alkyl sulfate / alkyl sulfonic acid or its salt is 0.001 to 2.0% by mass based on the total amount of the aqueous composition.

5. The aqueous composition according to claim 3, wherein, The (i) nitrogen-containing heterocyclic compound contains at least a nitrogen-containing 5-membered ring compound.

6. The aqueous composition according to claim 3, wherein, The (ii) cationic surfactant is selected from at least one of the ammonium salts represented by the following formula (4) and heteroaryl salts having a substituted or unsubstituted alkyl group with 10 to 30 carbon atoms, In the above formula (4), R 6 is a substituted or unsubstituted alkyl group having 10 to 30 carbon atoms, a substituted or unsubstituted alkyl(poly)heteroalkylene group having 10 to 30 carbon atoms, or a substituted or unsubstituted aryl(poly)heteroalkylene group having 10 to 30 carbon atoms, R 7 Each independently is 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, X - is a halide ion, a hydroxide ion, an organic sulfonate ion, a tetrafluoroborate anion, or a hexafluorophosphate anion.

7. The aqueous composition according to claim 3, wherein, The (iii) alkyl sulfate / alkyl sulfonic acid or its salt has at least an alkyl group with 6 to 30 carbon atoms.

8. The aqueous composition according to claim 1, wherein, The acid contains an inorganic acid other than nitric acid.

9. The aqueous composition according to claim 8, wherein, The acid contains at least phosphoric acid.

10. The aqueous composition according to claim 1, wherein, The oxidizing agent contains at least hydrogen peroxide.

11. An etching method, which includes the following steps: etching the seed layer of a semiconductor substrate having a seed layer containing copper using the aqueous composition according to any one of claims 1 to 10.

12. The etching method according to claim 11, wherein, The semiconductor substrate further has: a layer that is laminated in contact with the seed layer and contains a metal having a greater ionization tendency than copper.

13. A method for manufacturing a semiconductor substrate, which includes the following steps: etching the seed layer of a semiconductor substrate having a seed layer containing copper using the aqueous composition according to any one of claims 1 to 10.

14. The method for manufacturing a semiconductor substrate according to claim 13, wherein, The semiconductor substrate further has a layer that is laminated in contact with the seed layer and contains a metal having a greater ionization tendency than copper.

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