Etching solution, substrate processing method, and semiconductor device manufacturing method

Abstract

The present invention provides: an etching solution of which the etching properties with respect to SiOCN-containing materials have been suppressed and the etching properties with respect to SiGe-containing materials are good; a substrate processing method; and a semiconductor device manufacturing method. The etching solution according to the present invention comprises a specific compound having an acidic group and a basic group.

Description

Etching solution, substrate processing method, and semiconductor device manufacturing method

[0001] The present invention relates to an etching solution, a method for treating a substrate, and a method for manufacturing a semiconductor device.

[0002] As semiconductor devices become increasingly miniaturized, there is an increasing demand for highly efficient and accurate etching or cleaning processes using etchants during semiconductor device manufacturing processes. In particular, when multiple materials exist on a substrate, it is desirable to be able to selectively remove a specific material.

[0003] For example, Patent Document 1 describes an etching composition useful for selectively removing silicon germanium (SiGe) from a semiconductor substrate as an intermediate step in a multi-step semiconductor manufacturing process, which comprises: "at least one fluorine-containing acid, wherein the at least one fluorine-containing acid comprises hydrofluoric acid or hexafluorosilicic acid; at least one oxidizing agent; at least one catalyst comprising sulfuric acid, sulfonic acid, or phosphonic acid; at least one organic acid or anhydride thereof, wherein the at least one organic acid comprises formic acid, acetic acid, propionic acid, or butyric acid; at least one polymerized naphthalenesulfonic acid or a salt thereof; and at least one amine, wherein the at least one amine is represented by the formula (I): N-R １ R ２ R ３ (In the formula, R １ is OH or NH ２ C1-C8 alkyl optionally substituted with R ２ is H, or C1-C8 alkyl optionally substituted with OH, and R ３ is a C1-C8 alkyl optionally substituted with OH."

[0004] U.S. Pat. No. 1,182,0929

[0005] In some applications, in a workpiece containing silicon oxycarbon nitride (SiOCN) and silicon germanium (SiGe), it may be necessary to selectively etch (remove) at least a portion of the SiGe-containing material while suppressing etching of the SiOCN-containing material. The present inventors have studied the composition specifically disclosed in Patent Document 1 and found that it is difficult to improve the etching ability of the SiGe-containing material while suppressing etching ability of the SiOCN-containing material.

[0006] Therefore, an object of the present invention is to provide an etching solution that suppresses etching ability for SiOCN-containing materials and improves etching ability for SiGe-containing materials, as well as a substrate processing method and a semiconductor device manufacturing method.

[0007] As a result of extensive research into solving the above problems, the present inventors have found that the problems can be solved by the following configuration.

[0008] [1] An etching solution containing a specific compound having an acidic group and a basic group. [2] The etching solution according to [1], wherein the specific compound has a repeating unit A having an acidic group and a repeating unit B having a basic group, and the content ratio B / A, where A mol % is the content of the repeating unit A relative to all repeating units of the specific compound and B mol % is the content of the repeating unit B relative to all repeating units of the specific compound, is greater than 2 and not more than 50. [3] The etching solution according to [2], wherein the content ratio B / A is 5 to 50. [4] The etching solution according to any one of [1] to [3], wherein the weight-average molecular weight of the specific compound is 5,000 to 30,000. [5] The etching solution according to any one of [1] to [4], wherein the specific compound has an acidic group capable of dissociating in the etching solution at a rate of 1% or more. [6] The etching solution according to any one of [2] to [5], wherein the repeating unit A is a repeating unit having a sulfonic acid group. [7] The etching solution according to any one of [2] to [6], wherein the repeating unit B is a repeating unit having at least one group selected from the group consisting of a tertiary amino group and a quaternary ammonium base. [8] The etching solution according to any one of [2] to [7], wherein the repeating unit B has a quaternary ammonium base. [9] The etching solution according to any one of [1] to [8], wherein the etching solution contains an etchant compound.

[10] The etching solution according to [9], wherein the etchant compound contains a fluoride ion source.

[11] The etching solution according to any one of [1] to

[10] , wherein the content of the specific compound is 0.001 to 0.3 mass% with respect to the total mass of the etching solution.

[12] The etching solution according to any one of [1] to

[11] , wherein the etching solution is applied to a substrate having a silicon oxycarbonitride content.

[13] The etching solution according to any one of [1] to

[12] , wherein the etching solution is applied to a substrate having a silicon germanium content.

[14] The etching solution according to any one of [1] to

[13] , which is applied to a substrate having a silicon oxycarbonitride content and a silicon germanium content.

[15] A method for treating a substrate, comprising contacting a substrate having a silicon oxycarbon nitride-containing material and a silicon germanium-containing material with the etching solution according to any one of [1] to

[14] , and removing at least a portion of the silicon germanium-containing material contained in the substrate.

[16] A method for manufacturing a semiconductor device, comprising using the etching solution according to any one of [1] to

[14] .

[0009] According to the present invention, it is possible to provide an etching solution that suppresses etching of SiOCN-containing materials and improves etching of SiGe-containing materials, as well as a substrate processing method and a semiconductor device manufacturing method.

[0010] The present invention will be described in detail below. The following description of the constituent elements may be based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the upper and lower limits. In this specification, the upper or lower limit of a numerical range described in a stepwise manner may be replaced with the upper or lower limit of another stepwise manner. In this specification, the upper or lower limit of a numerical range described in a stepwise manner may be replaced with a value shown in the Examples. In this specification, each component may be a single substance corresponding to the component, or two or more substances may be used in combination. When two or more substances are used in combination for each component, the content of that component refers to the total content of the substances used in combination, unless otherwise specified.

[0011] In this specification, "(meth)acrylate" is a notation representing "acrylate" or "methacrylate", "(meth)acrylic" is a notation representing "acrylic" or "methacrylic", "(meth)acryloyl" is a notation representing "acryloyl" or "methacryloyl", and "(meth)acrylic acid" is a notation representing "acrylic acid" or "methacrylic acid".

[0012] In this specification, the term "SiOCN-containing material" refers to a material containing Si, O, C, and N elements, and is preferably a material composed essentially of only Si, O, C, and N elements. The term "substantially" means that the total content of Si, O, C, and N elements is 90 atomic % or more relative to the total atoms of the material. A material composed essentially of only Si, O, C, and N elements may contain other elements (e.g., B, P, etc.) as long as the total content of Si, O, C, and N elements is within the above range. The total content of Si, O, C, and N elements in the SiOCN-containing material is preferably 90 to 100 mass %, more preferably 99 to 100 mass %, and even more preferably 99.9 to 100 mass %, relative to the total mass of the SiOCN-containing material.

[0013] As used herein, the term "SiGe-containing material" refers to a material containing Si and Ge elements, and is preferably a material substantially composed of only Si and Ge elements. The term "substantially" means that the total content of Si and Ge elements is 90 atomic % or more relative to the total atoms of the material. A material substantially composed of only Si and Ge elements may contain other elements (e.g., C, N, O, B, and P) as long as the total content of Si and Ge elements is within the above range. The total content of Si and Ge elements in the SiGe-containing material is preferably 90 to 100 mass %, more preferably 99 to 100 mass %, and even more preferably 99.9 to 100 mass %, relative to the total mass of the SiGe-containing material. In the SiGe-containing material, the content of Ge elements (Ge / (Si+Ge)) relative to the total content of Si and Ge elements is preferably 60 atomic % or less, more preferably 50 atomic % or less, and even more preferably 45 atomic % or less. The lower limit of the content of Ge element relative to the total content of Si element and Ge element is preferably 5 atomic % or more, and more preferably 25 atomic % or more.

[0014] Unless otherwise specified, each component of the etching solution described in this specification may be ionized in the etching solution or may form a salt.

[0015] [Etching Solution] The etching solution of the present invention is an etching solution containing a specific compound having an acidic group and a basic group.

[0016] As described above, the etching solution of the present invention suppresses etching properties for SiOCN-containing materials and improves etching properties for SiGe-containing materials. The reason why these effects are exhibited is not clear in detail, but the inventors speculate as follows. Note that the following speculation does not limit the mechanism by which the effects are obtained. In other words, even if the effects are obtained by a mechanism other than the following, it is included in the scope of the present invention. First, the SiOCN-containing material is etched by SiO ２ and Si ３ N ４ Since the basic group in the specific compound has the element of SiO ２ The acidic group in the specific compound acts as an inhibitor of Si ３ N ４ It is believed that the specific compound has an acidic group and a basic group in one molecule, and therefore exhibits its inhibitory function while suppressing the formation of precipitates (polyion complexes) that accompany the combined use of an acidic compound and a basic compound, thereby suppressing the etching ability of SiOCN-containing materials and improving the etching ability of SiGe-containing materials.

[0017] The specific compounds and optional components contained in the etching solution of the present invention will be described in detail below.

[0018] [Specific Compound] As described above, the specific compound contained in the etching solution of the present invention is a compound having an acidic group and a basic group. The specific compound is not particularly limited as long as it has an acidic group and a basic group, but is preferably a polymer having a repeating unit A having an acidic group and a repeating unit B having a basic group.

[0019] For the reasons that etching properties for SiOCN-containing materials are further suppressed and etching properties for SiGe-containing materials are improved (hereinafter also abbreviated as "reasons for the superior effects of the present invention"), the content ratio B / A, where A mol % is the content of the repeating unit A relative to all repeating units of the specific compound and B mol % is the content ratio of the repeating unit B relative to all repeating units of the specific compound, is preferably more than 2 and not more than 50, more preferably 5 to 50, and even more preferably 8 to 35. The total content of the repeating unit A and the repeating unit B is not particularly limited, but is preferably 90 to 100 mol %, more preferably 95 to 100 mol %, relative to all repeating units of the specific compound.

[0020] When the specific compound has a repeating unit, the upper limit of the weight-average molecular weight of the specific compound is not particularly limited, but from the viewpoint of achieving better effects of the present invention, it is preferably 100,000 or less, more preferably 80,000 or less, even more preferably 50,000 or less, and particularly preferably 30,000 or less. Also, the lower limit of the weight-average molecular weight is not particularly limited, but from the viewpoint of achieving better effects of the present invention, it is preferably 500 or more, more preferably 800 or more, even more preferably 1,500 or more, and particularly preferably 5,000 or more. In this specification, the weight average molecular weight of a compound having a molecular weight distribution is defined as a polystyrene-equivalent value measured by GPC (Gel Permeation Chromatography) measurement using a GPC apparatus (Prominence UFLC manufactured by Shimadzu Corporation) [eluent: tetrahydrofuran, flow rate (sample injection amount): 50 μL, column: TSKgel GMHxL, TSKgel G4000HxL, TSKgel G2000HxL manufactured by Tosoh Corporation, column temperature: 40° C., flow rate: 1.0 mL / min, detector: differential refractive index detector].

[0021] <Acidic Group> The acidic group is not particularly limited, but examples thereof include a sulfonic acid group (—SO ３ H), phosphonic acid group (-PO ３ H ２ ), phosphinic acid group (-PO ２ H ２ ), phosphate group (-PO４ H ２ ), a carboxylic acid group (—COOH), and a phenolic hydroxy group.

[0022] In the present invention, the effect of the present invention is more excellent because, among others, the specific compound dissociates in the etching solution by 1% or more (proton (H ＋ It is preferable that the specific compound has acidic groups capable of releasing an acid dissociation constant (e.g., releasing an acid dissociation constant). Here, "acidic groups capable of dissociating" refers to acidic groups that dissociate in the etching solution due to the effects of pH, ionic strength, temperature, or the like. Furthermore, "dissociating at least 1%" means that 1% or more of the total number of acidic groups possessed by the specific compound dissociates, and in this specification, this is simply determined by the following discriminant (1): (pH of the etching solution of the present invention) ≥ (pKa of the acidic group possessed by the specific compound) - 2 ... Discriminant (1) For example, when the pH of the etching solution of the present invention is 1.0, if the acid dissociation constant of the acidic group possessed by the specific compound is 3.0 or less, the above discriminant (1) is satisfied, and therefore it can be said that the specific compound has acidic groups capable of dissociating at least 1% in the etching solution.

[0023] As described above, the specific compound preferably has a repeating unit A having an acidic group. The number of acidic groups contained in the repeating unit A of the specific compound is preferably 1 to 6, more preferably 1 or 2, and even more preferably 1. Examples of the repeating unit A include repeating units derived from sulfonic acid group-containing monomers such as styrenesulfonic acid (preferably p-styrenesulfonic acid), 2-acrylamido-2-methylpropanesulfonic acid, sulfonic acid-modified vinyl alcohol, 3-allyloxy-2-hydroxy-1-propanesulfonic acid, and naphthalenesulfonic acid, as well as carboxylic acid group-containing monomers such as acrylic acid and maleic acid. These may be used alone or in combination of two or more. In the present invention, it is preferable that the repeating unit A is a repeating unit having a sulfonic acid group, because this provides better effects of the present invention.

[0024] Examples of the repeating unit A include a repeating unit represented by the following formula (b).

[0025]

[0026] In formula (b), R ｂ１ , R ｂ２ and R ｂ３ each independently represents a hydrogen atom, an alkyl group, or a functional group having an acidic group. ｂ represents a single bond or a (k+1)-valent linking group. A represents an acidic group. k represents an integer of 1 to 4. When multiple acidic groups are present in formula (b), the multiple acidic groups may be the same or different.

[0027] The alkyl group may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group is preferably 1 to 12, more preferably 1 to 6, and even more preferably 1 to 3. Examples of the functional group having an acidic group include -L in formula (b). ｂ -(A) ｋ Examples of the group include a group represented by the following formula: ｂ , A and k will be described in detail later. ｂ１ , R ｂ２ and R ｂ３ is preferably a hydrogen atom, a methyl group, an ethyl group, or a carboxy group, and more preferably a hydrogen atom, a methyl group, or a carboxy group. ｂ１ , R ｂ２ and R ｂ３ It is preferred that one of represents a hydrogen atom, a methyl group or a carboxylic acid group, and the remaining two each represent a hydrogen atom.

[0028] L ｂ The (k+1)-valent linking group represented by the formula (I) is not particularly limited as long as it is a group having a valence corresponding to the number of A, and examples thereof include an optionally substituted di- to pentavalent aliphatic hydrocarbon group, an optionally substituted di- to pentavalent aromatic hydrocarbon group, an optionally substituted di- to pentavalent aromatic heterocyclic group, -O-, -CO-, -SO ２ -, -NR Ｌ -, -N<, and groups formed by combining these. Ｌ The definition of R ＮWhen k is 1, the divalent linking group may be a divalent aliphatic hydrocarbon group, a divalent aromatic hydrocarbon group, a divalent aromatic heterocyclic group, —O—, —CO—, —SO ２ -, -NR Ｌ -, and groups formed by combining these. As the divalent aliphatic hydrocarbon group, an alkylene group having 1 to 6 carbon atoms (preferably 1 to 3 carbon atoms) is preferred. L ｂ is more preferably a single bond, a methylene group, or a phenylene group.

[0029] Specific examples of the acidic group represented by A are as described above. k is preferably an integer of 1 to 3, and more preferably 1 or 2.

[0030] <Basic Group> The basic group is not particularly limited, and examples thereof include nitrogen-containing groups. Examples of the nitrogen-containing group include an amino group (—NR Ｎ ２ ), quaternary ammonium base (-N ＋ R Ｎ ３ ), a hydrazine group, a guanidine group, and a nitrogen-containing heterocyclic group. Ｎ R each independently represents a hydrogen atom or an organic group (a group containing at least one carbon atom). Ｎ The number of carbon atoms in the organic group represented by the formula (I) is preferably 1 to 10, more preferably 1 to 6, and still more preferably 1 to 3. Examples of the nitrogen-containing heterocyclic group include nitrogen-containing aromatic heterocyclic groups such as a pyrrole group, an imidazole group, a pyrazole group, an oxazolyl group, a triazole group, a benzimidazole group, a benztriazole group, a pyridyl group, and a triazine group, and nitrogen-containing aliphatic heterocyclic groups such as a pyrrolidinyl group, a piperidinyl group, and a piperazinyl group.

[0031] As described above, the specific compound preferably has a repeating unit B having a basic group. The number of basic groups contained in the repeating unit B of the specific compound is preferably 1 to 6, more preferably 1 or 2, and even more preferably 1. In the present invention, for reasons of better effects of the present invention, the repeating unit B is preferably a repeating unit having at least one group selected from the group consisting of a tertiary amino group and a quaternary ammonium base, and more preferably a repeating unit B having a quaternary ammonium base. When the basic group is a tertiary amino group or a quaternary ammonium base, the number of carbon atoms contained in the tertiary amino group or the quaternary ammonium base is preferably 1 to 20, more preferably 1 to 15, and even more preferably 1 to 10. Examples of the repeating unit B include repeating units derived from quaternized dialkylaminoalkyl (meth)acrylate monomers such as N,N-dimethylaminoethyl methacrylate diethyl sulfate and N,N-dimethylacrylamide; diallyl quaternary ammonium salt monomers such as diallyldimethylammonium chloride, diallylamine amide sulfate, methyldiallylamine and diallylmethylethylammonium ethyl sulfate; and monomers such as vinylimidazolium trichloride, cationized vinyl alcohol, vinylpyrrolidone, vinylcaprolactam, (meth)acrylamidopropyl trimethylammonium chloride, alkylacrylamide, alkylaminoalkylacrylamide, dimethylaminohydroxypropylethylenetriamine and methacryloylethyltrimethylammonium chloride. These may be used alone or in combination of two or more.

[0032] The repeating unit B is preferably a repeating unit represented by general formula (1-a) or a repeating unit represented by general formula (1-b).

[0033]

[0034] In general formula (1-a), L １ａ and L ２ａ each independently represents a single bond or a methylene group. １ａ is a single bond, L２ａ is a methylene group, and L １ａ is a methylene group, L ２ａ is a single bond. １ａ is preferably a single bond, and L ２ａ is preferably a methylene group.

[0035] In general formula (1-a), X represents a group represented by formula (X1) or a group represented by formula (X2). * represents a bonding position. In formula (X1) and formula (X2), R １ａ represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a hydroxyl group, or an aralkyl group having 7 to 10 carbon atoms. The alkyl group having 1 to 10 carbon atoms which may have a hydroxyl group may be linear, branched, or cyclic, and examples thereof include alkyl groups having 1 to 4 carbon atoms which may have a hydroxyl group, of which methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 2-hydroxybutyl, 3-hydroxybutyl, 4-hydroxybutyl, or cyclohexyl groups are preferred. Examples of aralkyl groups having 7 to 10 carbon atoms include benzyl, methylbenzyl, naphthylmethyl, and phenethyl groups. R １ａ Among these, a hydrogen atom, a methyl group, an ethyl group, or a benzyl group is preferable as the aryl group.

[0036] D － represents a monovalent anion. － Examples of the monovalent anion represented by the formula (I) include a halide ion (e.g., a chloride ion), a sulfate ion, a nitrate ion, an acetate ion, a methyl sulfate ion, an ethyl sulfate ion, a sulfamate ion, and a hydroxide ion.

[0037] In general formula (1-b), L １ｂ and L ２ｂ each independently represents a single bond or a methylene group. １ｂ is a single bond, L ２ｂ is a methylene group, and L １ｂ is a methylene group, L ２ｂis a single bond. １ｂ is preferably a single bond, and L ２ｂ is preferably a methylene group.

[0038] In general formula (1-b), R １ｂ and R ２ｂ each independently represents an alkyl group having 1 to 10 carbon atoms which may have a hydroxyl group, or an aralkyl group having 7 to 10 carbon atoms. Specific examples and preferred embodiments of the alkyl group having 1 to 10 carbon atoms which may have a hydroxyl group and the aralkyl group having 7 to 10 carbon atoms are １ａ These are the same as the specific examples and preferred embodiments of the alkyl group having 1 to 10 carbon atoms and optionally having a hydroxyl group, and the aralkyl group having 7 to 10 carbon atoms, represented by the following formula:

[0039] In general formula (1-b), D － represents a monovalent anion. － Examples of the monovalent anion represented by the formula (1-a) include D － Examples of the monovalent anion include the ions exemplified above.

[0040] In general formula (1-b), R １ｂ , R ２ｂ and D － Examples of the combination of D are shown in Examples 1 to 5 below, and among them, Examples 1, 5 and 6 are preferred. － The chloride ion represented by the formula (I) may be replaced by an anion selected from bromide, iodide, methyl sulfate and ethyl sulfate.

[0041] Example 1: R １ｂ =R ２ｂ = methyl group, D － = Chloride ion Example 2: R １ｂ =R ２ｂ = ethyl group, D － = chloride ion Example 3: R １ｂ =R ２ｂ = propyl group, D － = chloride ion Example 4: R １ｂ =R ２ｂ = butyl group, D － = chloride ion Example 5: R １ｂ = ethyl group, R２ｂ = benzyl group, D － = chloride ion Example 6: R １ｂ = methyl group, R ２ｂ = ethyl group, D － = Ethyl sulfate ion

[0042] The repeating unit B may be a repeating unit represented by general formula (1-c).

[0043]

[0044] In general formula (1-c), Y represents a group represented by formula (Y1) or a group represented by formula (Y2). * represents a bonding position. L represents a single bond or a divalent linking group. Examples of the divalent linking group include a divalent aliphatic hydrocarbon group, a divalent aromatic hydrocarbon group, a divalent aromatic heterocyclic group, -O-, -CO-, and -SO ２ -, -NR Ｌ -, -P(=O)(-O － )- and groups formed by combining these. Ｌ The definition of R Ｎ It is the same as R １ｃ and R ２ｃ each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a hydroxyl group, or an aralkyl group having 7 to 10 carbon atoms. Specific examples and preferred embodiments of the alkyl group having 1 to 10 carbon atoms which may have a hydroxyl group and the aralkyl group having 7 to 10 carbon atoms are １ａ These are the same as the specific examples and preferred embodiments of the alkyl group having 1 to 10 carbon atoms and optionally having a hydroxyl group, and the aralkyl group having 7 to 10 carbon atoms, represented by the following formula: － represents a monovalent anion. － Examples of the monovalent anion represented by the formula (1-a) include D － Examples of the monovalent anion include the ions exemplified above.

[0045] In the present invention, the content of the specific compound is preferably 0.001 to 0.3 mass%, more preferably 0.003 to 0.1 mass%, and even more preferably 0.01 to 0.06 mass%, relative to the total mass of the etching solution, for reasons why the effects of the present invention are more excellent.

[0046] [Etchant Compound] The etching solution of the present invention preferably contains an etchant compound to enhance the effects of the present invention. The etchant compound is not particularly limited, and chemical solutions of acids, alkalis, or alkali metal salts can be used as appropriate. Examples of acids include hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, hydrogen peroxide, and acetic acid. Examples of alkalis include caustic soda and caustic potash. Examples of alkali metal salts include alkali metal silicates such as sodium metasilicate, sodium silicate, potassium metasilicate, and potassium silicate; alkali metal carbonates such as sodium carbonate and potassium carbonate; alkali metal aluminates such as sodium aluminate and potassium aluminate; alkali metal aldonic acid salts such as sodium gluconate and potassium gluconate; and alkali metal hydrogen phosphates such as sodium diphosphate, potassium diphosphate, sodium triphosphate, and potassium triphosphate.

[0047] <Fluoride Ion Source> In the present invention, the etchant compound preferably contains a fluoride ion source, because the effects of the present invention are more excellent. Here, the fluoride ion source is a fluoride ion source that generates fluoride ions (F － ) or a compound capable of releasing a fluoride ion source. The fluoride ion source may be in the form of a fluoride ion or a fluorine-containing ion. Examples of fluorine-containing ions include bifluoride ions (HF ２ － ), SiF ６ ２－ , TiF ６ ２－ , ZrF ６ ２－ , P.F. ６ － , and BF ４ －The fluoride ion source is often a salt of a fluoride ion or a fluorine-containing ion with a cation. Preferred cations contained in the fluoride ion source include H ＋ , Li ＋ , Na ＋ , K. ＋ , and N.H. ４ ＋ are mentioned, and H ＋ is preferred.

[0048] Examples of fluoride ion sources include hydrofluoric acid (HF) and ammonium fluoride (NH ４ F), hexafluorosilicic acid and its salts (H ２ SiF ６ , Na ２ SiF ６ etc.), fluoroboric acid and its salts (KBF ４ , N.H. ４ BF ４ etc.), fluoroboric acid, hexafluorotitanic acid (H ２ TiF ６ ), hexafluorozirconate (H ２ ZrF ６ ), hexafluorophosphate (HPF ６ ), and hexafluoroboric acid (HBF ４ ) are exemplified, hydrofluoric acid or ammonium fluoride is preferred, and hydrofluoric acid is more preferred.

[0049] The etchant compound may be used alone or in combination of two or more. The content of the etchant compound is preferably 0.005 to 10.0 mass %, more preferably 0.01 to 5.0 mass %, and even more preferably 0.1 to 1.0 mass %, relative to the total mass of the etching solution, because this provides better effects of the present invention. As the etchant compound (particularly, a fluoride ion source), a solution containing a fluoride ion source may be used. When a solution containing a fluoride ion source is used as the etchant compound, the content of the etchant compound is the content of the fluoride ion source contained in the solution.

[0050] [Oxidizing Agent] The etching solution of the present invention preferably contains an oxidizing agent. The lower limit of the standard oxidation-reduction potential of the oxidizing agent is not particularly limited, but is preferably 1.0 V or more, more preferably 1.3 V or more, and even more preferably 1.5 V or more. The upper limit of the standard oxidation-reduction potential of the oxidizing agent is not particularly limited, but is preferably 4.0 V or less, more preferably 2.5 V or less. The standard oxidation-reduction potential is based on a standard hydrogen electrode.

[0051] Examples of the oxidizing agent include hydrogen peroxide, and peroxides such as peracetic acid, performic acid, perpropionic acid, and salts thereof; perhalogen acid compounds such as periodic acid, perchloric acid, and salts thereof; oxide halides such as iodic acid, chloric acid, hypochlorous acid, and salts thereof; nitric acid compounds such as nitric acid, cerium nitrate, and iron nitrate; persulfates, persulfates, persulfates, peroxodisulfate, peroxodisulfate; persulfides; percarbonates; perboric acid and salts thereof; permanganates; isocyanuric acid compounds such as isocyanuric acid, trichloroisocyanuric acid, and salts thereof; cerium compounds; and ferricyanides such as potassium ferricyanide. Peroxides or perhalogen acid compounds are preferred, and peroxides are more preferred. The periodic acid includes metaperiodic acid (HIO ４ ), and orthoperiodic acid (H ５ IO ６ ) are included. Among them, the oxidizing agent is preferably periodic acid (standard oxidation-reduction potential 1.6 V), hydrogen peroxide (standard oxidation-reduction potential 1.8 V), peracetic acid (standard oxidation-reduction potential 1.4 V), performic acid, or perpropionic acid, with hydrogen peroxide being more preferred. Note that the etching solution may contain a component resulting from a reaction between the oxidizing agent and a solvent described below. For example, when the etching solution contains hydrogen peroxide, an acidic compound (e.g., sulfuric acid), and acetic acid, part of the hydrogen peroxide may react with the acetic acid to generate peracetic acid, and the peracetic acid may function as the oxidizing agent.

[0052] The oxidizing agent may be used alone or in combination of two or more. The content of the oxidizing agent is preferably 0.01 to 10 mass %, more preferably 0.1 to 10 mass %, and still more preferably 3.0 to 10 mass %, relative to the total mass of the etching solution.

[0053] [Solvent] The etching solution of the present invention preferably contains a solvent. Examples of the solvent include water and an organic solvent. The organic solvent is preferably a water-soluble organic solvent. The water-soluble organic solvent refers to an organic solvent having a solubility in water (100 g) at 25°C of 20 g / 100 g or more. For reasons of superior effects of the present invention, the solvent preferably contains a water-soluble organic solvent, and more preferably contains water and a water-soluble organic solvent.

[0054] Examples of organic solvents include alcohol-based solvents, carboxylic acid-based solvents, ether-based solvents, sulfoxide-based solvents, ester-based solvents, ketone-based solvents, sulfone-based solvents, amide-based solvents, and nitrile-based solvents. Of these, solvents selected from the group consisting of alcohol-based solvents, carboxylic acid-based solvents, ether-based solvents, and sulfoxide-based solvents are preferred, and carboxylic acid-based solvents are more preferred.

[0055] Examples of alcohol solvents include methanol, ethanol, 1-propanol, 2-propanol, t-butyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol, 2-pentanol, t-pentyl alcohol, hexanol, 3-methoxy-3-methyl-1-butanol, 3-methoxy-1-butanol, 1-methoxy-2-butanol, allyl alcohol, propargyl alcohol, 2-butenyl alcohol, 3-butenyl alcohol, 4-penten-2-ol, tetrahydrofurfuryl alcohol, furfuryl alcohol, and and benzyl alcohol, and polyols such as glycerin, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 2-methyl-1,3-propanediol, 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2,3-butanediol, hexylene glycol, pinacol, and 1,3-cyclopentanediol.

[0056] Examples of carboxylic acid solvents include formic acid, acetic acid, and propionic acid.

[0057] Examples of ether solvents include dialkyl ethers such as diethyl ether, diisopropyl ether, dibutyl ether, t-butyl methyl ether, and cyclohexyl methyl ether; glycol ethers such as ethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, tetraethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, triethylene glycol diethyl ether, tetraethylene glycol diethyl ether, ethylene glycol dimethyl ether, triethylene glycol dimethyl ether, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, diethylene glycol monomethyl ether, diethylene glycol propyl ether, diethylene glycol monobutyl ether, diethylene glycol monoethyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, and triethylene glycol monobutyl ether; and cyclic ethers such as tetrahydrofuran and 1,4-dioxane.

[0058] An example of a sulfoxide solvent is dimethyl sulfoxide (DMSO).

[0059] Examples of ester solvents include chain esters such as ethyl acetate, butyl acetate, ethyl lactate, methyl 3-methoxypropanoate, propylene glycol monomethyl ether acetate, ethylene glycol monoacetate, diethylene glycol monoacetate, ethylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol diacetate, and propylene glycol diacetate, and cyclic esters such as propylene carbonate, ethylene carbonate, and diethyl carbonate.

[0060] Examples of solvents other than those mentioned above include ketone solvents such as acetone, dimethyl ketone (propanone), cyclobutanone, cyclopentanone, cyclohexanone, methyl ethyl ketone (2-butanone), 5-hexanedione, methyl isobutyl ketone, 1,4-cyclohexanedione, 1,3-cyclohexanedione, and cyclohexanone; amide solvents such as N-methyl-2-pyrrolidone, N,N-dimethylformamide, 1-methyl-2-pyrrolidone, 2-pyrrolidinone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, formamide, N-methylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpropanamide, and hexamethylphosphoric triamide; sulfone solvents such as sulfolane, 3-methylsulfolane, and 2,4-dimethylsulfolane; and nitrile solvents such as acetonitrile.

[0061] The water-soluble organic solvent preferably contains at least one selected from the group consisting of formic acid, acetic acid, propionic acid, and ethylene glycol monobutyl ether (EGBE), more preferably contains at least one selected from the group consisting of acetic acid, propionic acid, and EGBE, and even more preferably contains acetic acid.

[0062] The solvent may be used alone or in combination of two or more. The lower limit of the solvent content is not particularly limited, but is preferably 60% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, relative to the total mass of the etching solution. The upper limit of the solvent content is not particularly limited, but is less than 100% by mass, preferably 99.5% by mass or less, and more preferably 99% by mass or less, relative to the total mass of the etching solution. When the etching solution of the present invention contains a water-soluble organic solvent, the lower limit of the water-soluble organic solvent content is not particularly limited, but is preferably 30% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more, relative to the total mass of the etching solution. The upper limit of the water-soluble organic solvent content is not particularly limited, but is preferably 95% by mass or less, more preferably less than 90% by mass, and even more preferably 80% by mass or less, relative to the total mass of the etching solution.

[0063] [Other Additives] The etching solution of the present invention may contain additives other than the above-mentioned components. Examples of other additives include basic compounds, acidic compounds, surfactants, antifoaming agents, and unsaturated compounds. Note that all of these components are compounds different from the above-mentioned etchant compound, specific compound, and oxidizing agent.

[0064] <Basic Compound> The etching solution may contain a basic compound. Examples of the basic compound include organic basic compounds and inorganic basic compounds. Examples of the organic basic compound include amine compounds, quaternary ammonium salts, amine oxide compounds, nitro compounds, nitroso compounds, oxime compounds, ketoxime compounds, aldoxime compounds, lactam compounds, and isocyanide compounds. Note that the organic basic compound is a compound different from the heterocyclic compound described above. Examples of the inorganic basic compound include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkaline earth metal hydroxides, and ammonia or salts thereof.

[0065] The content of the basic compound is not particularly limited, but is preferably 0.1 to 20 mass %, more preferably 0.5 to 10 mass %, based on the total mass of the etching solution.

[0066] <Acidic Compound> The etching solution may contain an acidic compound. Examples of the acidic compound include inorganic acidic compounds. Examples of the inorganic acidic compound include hydrochloric acid, sulfuric acid, phosphoric acid, boric acid, and phosphonic acid, and sulfuric acid is preferred.

[0067] The content of the acidic compound is not particularly limited, but is preferably 0.1 to 10 mass %, more preferably 0.5 to 5 mass %, based on the total mass of the etching solution.

[0068] <Surfactant> The etching solution may contain a surfactant. The surfactant is not particularly limited as long as it is a compound having a hydrophilic group and a hydrophobic group (lipophilic group) in one molecule, and examples thereof include nonionic surfactants, cationic surfactants, and anionic surfactants. The surfactant often has at least one hydrophobic group selected from the group consisting of an aliphatic hydrocarbon group, an aromatic hydrocarbon group, and a combination thereof. The total carbon number of the surfactant is preferably 16 to 100.

[0069] Examples of the nonionic surfactant include ester-type nonionic surfactants, ether-type nonionic surfactants, and ester-ether-type nonionic surfactants, and ether-type nonionic surfactants are preferred. Examples of the nonionic surfactant include the compounds exemplified in paragraph

[0126] of WO 2022 / 044893, the contents of which are incorporated herein by reference.

[0070] Examples of cationic surfactants include primary to tertiary alkylamine salts (e.g., monostearyl ammonium chloride, distearyl ammonium chloride, and tristearyl ammonium chloride), and modified aliphatic polyamines (e.g., polyethylene polyamine).

[0071] Examples of anionic surfactants include sulfonic acid surfactants having a sulfonic acid group, sulfate ester surfactants having a sulfate ester group, and carboxylic acid surfactants having a carboxylic acid group. Examples of anionic surfactants include the compounds exemplified in paragraphs

[0116] to

[0123] of WO 2022 / 044893, the contents of which are incorporated herein by reference.

[0072] <Antifoaming Agent> The etching solution may contain an antifoaming agent. Surfactants may cause foaming depending on how they are used. Therefore, it is preferable that an etching solution containing a surfactant contains an antifoaming agent that suppresses the generation of foaming, shortens the lifespan of the generated foam, and suppresses the residual foam. The antifoaming agent is not particularly limited as long as it does not impair the effects of the present invention, and examples thereof include silicone-based antifoaming agents, acetylene diol-based antifoaming agents, fatty acid ester-based antifoaming agents, and long-chain aliphatic alcohol-based antifoaming agents. Among these, silicone-based antifoaming agents are preferred because of their superior effect of suppressing residual foam. It should be noted that the antifoaming agent does not include compounds contained in the above-mentioned surfactants.

[0073] <Unsaturated Compound> The etching solution may contain an unsaturated compound. The unsaturated compound is a compound containing a carbon-carbon unsaturated bond, and is preferably a compound containing a carbon-carbon double bond. The unsaturated compound preferably has at least one structure selected from the group consisting of a carboxylic acid group, an amide group, a hydroxy group, an ester bond, and an ether bond, and more preferably has at least one structure selected from the group consisting of a carboxylic acid group and a polyalkylene glycol structure. Examples of unsaturated compounds include unsaturated fatty acids such as linoleic acid, oleic acid, and sorbic acid, polyalkylene glycol alkenylene ethers such as polyoxyethylene oleyl ether, polyalkylene glycol unsaturated fatty acid esters such as polyethylene glycol oleate and polyethylene glycol linoleate, sorbitol unsaturated fatty acid esters such as sorbitol tetraoleate, sorbitol trioleate, sorbitol dioleate, and sorbitol monooleate, sorbitan unsaturated fatty acid esters such as sorbitan monooleate and sorbitan trioleate, oleamide, ethylene glycol monoallyl ether, allyl methyl ether, glycerol α,α'-diallyl ether, pentaerythritol tetraallyl ether, ethylene glycol monovinyl ether, maleic acid, 3-phenyl-2-propen-1-ol, and 1,2-epoxy-5-hexene.

[0074] The content of the unsaturated compound is preferably 0.001 to 10 mass %, more preferably 0.005 to 5 mass %, based on the total mass of the etching solution.

[0075] [Physical Properties of Etching Solution] <Turbidity> The turbidity of the etching solution is preferably less than 10 NTU, and more preferably 0.01 or more and less than 10 NTU. Here, the turbidity of the etching solution is determined by directly measuring the chemical solution of the present invention using a turbidity meter (TN-100IR, manufactured by Thermo Scientific) to measure the transmitted light (parallel light from an LED light source) attenuated by the turbidity substance and calculating the ratio to the incident light. Note that formagine turbidity (NTU) is used as the unit of measurement for turbidity.

[0076] <pH> The pH of the etching solution is preferably 0.5 to 9, more preferably 1 to 7. The pH of the etching solution can be measured using a known pH meter by a method in accordance with JIS Z8802-1984. The measurement temperature is 25°C.

[0077] <Metal Content> The content (measured as ion concentration) of metals (e.g., metal elements Fe, Co, Na, Cu, Mg, Mn, Li, Al, Cr, Ni, Zn, Sn, and Ag) contained as impurities in the etching solution is preferably 5 mass ppm or less, more preferably 1 mass ppm or less. In particular, the metal content is more preferably a value lower than 1 mass ppm, that is, a mass ppb order or less, particularly preferably 100 mass ppb or less, and most preferably less than 10 mass ppb. The lower limit is preferably 0.

[0078] <Insoluble Particles> The etching solution of the present invention preferably contains substantially no insoluble particles. The term "insoluble particles" refers to particles of inorganic solids or organic solids that do not dissolve in the etching solution and ultimately exist as particles. The term "substantially free of insoluble particles" refers to a measurement composition obtained by diluting the etching solution 10,000 times with a solvent contained in the etching solution, and the number of particles with a particle size of 50 nm or more contained in 1 mL of the measurement composition is 40,000 or less. The number of particles contained in the measurement composition can be measured in the liquid phase using a commercially available particle counter. Commercially available particle counters include those manufactured by Rion Corporation and PMS. A representative example of the former is the KS-19F, and a representative example of the latter is the Chem20. To measure larger particles, instruments such as the KS-42 series and the LiQuilaz II S series can be used. Examples of insoluble particles include particles of inorganic solids such as silica (including colloidal silica and fumed silica), alumina, zirconia, ceria, titania, germania, manganese oxide, and silicon carbide; and particles of organic solids such as polystyrene, polyacrylic resin, and polyvinyl chloride. Methods for removing insoluble particles from the etching solution include purification treatments such as filtering. In addition, it is preferable that the etching solution does not contain abrasive grains.

[0079] <Coarse Particles> The etching solution may contain coarse particles, but the content thereof is preferably low. Coarse particles refer to particles having a diameter (particle size) of 1 μm or more when the particle shape is considered as a sphere. The coarse particles contained in the etching solution include particles such as dust, dirt, organic solids, and inorganic solids contained as impurities in the raw material, as well as particles such as dust, dirt, organic solids, and inorganic solids brought in as contaminants during preparation of the etching solution, and these particles ultimately remain as particles in the etching solution without dissolving.

[0080] The content of coarse particles in the etching solution is preferably 100 or less, more preferably 50 or less, particles having a particle size of 1 μm or more per mL of the etching solution. The lower limit is preferably 0 or more, more preferably 0.01 or more, per mL of the etching solution. The content of coarse particles present in the etching solution can be measured in the liquid phase using a commercially available measuring device that uses a laser as a light source and is a liquid-borne particle measuring method based on light scattering.

[0081] [Method for Producing Etching Solution] The etching solution of the present invention can be produced by a known method.

[0082] [Solution Preparation Step] Examples of methods for preparing the etching solution include a method of mixing the above-mentioned components. The order and / or timing of mixing the above-mentioned components are not particularly limited, and examples include a method of sequentially adding a specific compound and, if necessary, optional components to a container containing a solvent, and then stirring and mixing. Alternatively, the solution may be prepared by adjusting the pH of the mixed solution by adding a pH adjuster. Furthermore, when adding each component to a container, they may be added all at once, or may be added in multiple divided portions.

[0083] The etching solution may be prepared using a known agitator or disperser as the agitator and a stirring method. Examples of the agitator include an industrial mixer, a portable agitator, a mechanical stirrer, and a magnetic stirrer. Examples of the disperser include an industrial disperser, a homogenizer, an ultrasonic disperser, and a bead mill.

[0084] The mixing of the components in the etching solution preparation step, the purification treatment described below, and the storage of the produced etching solution are preferably carried out at 40° C. or lower, more preferably at 30° C. or lower. The lower limit is preferably 5° C. or higher, more preferably 10° C. or higher. By preparing, treating, and / or storing the etching solution within the above temperature range, the performance can be stably maintained for a long period of time.

[0085] The etching solution of the present invention may be prepared as a kit in which the raw materials are divided into a plurality of parts. When the etching solution of the present invention is prepared as a kit, the raw materials may be mixed in a predetermined ratio at the time of use or before use to obtain the etching solution of the present invention. The etching solution may also be prepared as a concentrated solution. In this case, a diluted solution obtained by diluting with a dilution liquid before use is used. In other words, the kit may include the etching solution in the form of a concentrated solution and the dilution liquid.

[0086] <Purification> It is preferable to perform a purification treatment in advance on one or more of the raw materials used to prepare the etching solution. Furthermore, if necessary, the etching solution may also be purified. The degree of purification is preferably such that the raw materials have a purity of 99% by mass or more, and more preferably such that the purity of the stock solution has a purity of 99.9% by mass or more. The upper limit is preferably 99.9999% by mass or less.

[0087] Examples of purification methods include passing the raw material through an ion exchange resin or a reverse osmosis membrane (RO membrane), reprecipitation, distillation of the raw material, and filtering. Any filter conventionally used for filtration can be used without particular limitations. Examples of materials constituting the filter include filters made of fluororesins such as polytetrafluoroethylene (PTFE) and tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA), polyamide resins such as nylon, polyallylsulfone (PAS), and polyolefin resins (including high-density or ultra-high molecular weight) such as polyethylene and polypropylene (PP). Among these materials, materials selected from the group consisting of polyethylene, polypropylene (including high-density polypropylene), fluororesins (including PTFE and PFA), and polyamide resins (including nylon) are preferred, with fluororesin filters being more preferred. Filtering the raw material using filters made of these materials effectively removes highly polar contaminants that are likely to cause defects.

[0088] The purification treatment may be carried out by combining two or more of the above purification methods, or may be carried out multiple times.

[0089] <Container> The container for storing the etching solution, concentrated solution, or kit described above is not particularly limited, and any known container can be used as long as corrosiveness by the solution is not a problem. Specific examples of the container include the "Clean Bottle" series manufactured by Aicello Chemical Co., Ltd. and the "Pure Bottle" manufactured by Kodama Resin Industry Co., Ltd. In addition, for the purpose of preventing impurities from being mixed (contaminated) into the raw materials and etching solution, it is also preferable to use a multilayer container whose inner wall has a six-layer structure made of six types of resin, or a multilayer container whose inner wall has a seven-layer structure made of six types of resin. Examples of such containers include, but are not limited to, the containers described in JP 2015-123351 A. In addition, the containers exemplified in paragraphs

[0121] to

[0124] of WO 2022 / 004217 can also be used as containers, and the contents of these containers are incorporated herein by reference.

[0090] The interior of these containers is preferably cleaned before filling with the etching solution. The liquid used for cleaning is preferably one that has a reduced amount of metal impurities. After production, the etching solution may be bottled in a container such as a gallon bottle or a coated bottle, and then transported and stored.

[0091] To prevent changes in the components of the etching solution during storage, the container may be filled with an inert gas (such as nitrogen or argon) with a purity of 99.99995% by volume or higher. Gases with low water content are particularly preferred. The etching solution may be transported and stored at room temperature, or the temperature may be controlled to a range of -20°C to 20°C to prevent deterioration.

[0092] The method for producing the etching solution may further include a static elimination step of eliminating static electricity from the etching solution.

[0093] [Uses] The etching solution of the present invention is used for processing semiconductor substrates. More specifically, it is preferably used for semiconductor devices. "For semiconductor devices" means that it is used during the manufacture of semiconductor devices. The etching solution can be used in the manufacturing process of semiconductor devices, for example, to treat SiOCN-containing materials, SiGe-containing materials, Si-containing materials, insulating films, resist films, anti-reflective films, etching residues, and ashing residues (hereinafter simply referred to as "residues") present on a substrate. The etching solution may also be used for processing semiconductor substrates after chemical mechanical polishing. The etching solution of the present invention is preferably applied to substrates containing at least one of SiOCN-containing materials and SiGe-containing materials, and more preferably to substrates containing both SiOCN-containing materials and SiGe-containing materials. Therefore, the etching solution of the present invention can be suitably used as a solution (etching solution) for removing at least a portion of the SiGe-containing materials from a substrate containing SiOCN-containing materials and SiGe-containing materials.

[0094] [Method for Manufacturing a Semiconductor Device] The method for manufacturing a semiconductor device of the present invention uses the etching solution of the present invention described above. Specifically, a preferred example is a substrate processing method in which a substrate having SiOCN-containing and SiGe-containing materials (hereinafter also simply referred to as "workpiece") is contacted with the etching solution of the present invention to remove at least a portion of the SiGe-containing materials in the substrate. By contacting the workpiece with the etching solution, the etching ability of the SiOCN-containing materials in the workpiece is suppressed, and the SiGe-containing materials in the workpiece are selectively removed (etched). Methods for contacting the workpiece with the etching solution include, for example, immersing the workpiece in the etching solution contained in a tank, spraying the etching solution on the workpiece, flowing the etching solution on the workpiece, and combinations thereof. Immersing the workpiece in the etching solution is preferred.

[0095] The treatment time for contacting the etching solution can be adjusted as appropriate. The treatment time (contact time between the etching solution and the object to be treated) is preferably 0.5 to 60 minutes, more preferably 1 to 20 minutes. The temperature of the etching solution during treatment is preferably 10 to 100°C, more preferably 15 to 60°C.

[0096] The method for manufacturing a semiconductor device of the present invention may include other process steps in addition to the process of contacting an etching solution, such as processes for forming structures such as metal wiring, gate structures, source structures, drain structures, insulating films, ferromagnetic layers, and nonmagnetic layers (e.g., layer formation, etching, chemical mechanical polishing, and modification), resist formation, exposure, and removal, heat treatment, cleaning, and inspection.

[0097] The above processing method may be performed at any stage of the back end process (BEOL: Back end of the line), middle process (MOL: Middle of the line), or front end process (FEOL: Front end of the line), and is preferably performed in the front end process or middle process.

[0098] The present invention will be described in more detail below with reference to the following examples. The materials, amounts used, ratios, treatment details, and treatment procedures shown in the following examples can be modified as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the following examples. Furthermore, all of the components used in the examples and comparative examples were classified as semiconductor grade or equivalent high purity grade.

[0099] [Preparation of Etching Solution] Acetic acid, hydrogen peroxide, sulfuric acid, and water were mixed to the values ​​shown in the table below, and the mixture was stirred for 68 hours. Next, the specific compound, hydrogen fluoride, water, and other optional components were added to the resulting mixture in this order to the values ​​shown in the table below, and the mixture was stirred to prepare the etching solutions of each Example and Comparative Example. The components used in preparing the etching solutions are as follows:

[0100] [Fluoride ion source] HF (hydrogen fluoride)

[0101] [Oxidizing agent] Hydrogen peroxide (H ２ O ２ , standard redox potential 1.8 V)

[0102] [Specific Compounds] The structural formulas of polymers E1 to E10 used as specific compounds are shown below. For each polymer, the weight average molecular weight (Mw) and the content ratio (n / m, molar ratio) of repeating unit A to repeating unit B are also shown below.

[0103]

[0104] Polymer E1: n / m = 3 / 2 Polymer E2: n / m = 2.1 / 1 Polymer E3: n / m = 8 / 2 Polymer E4: n / m = 5 / 1 Polymer E5: n / m = 9 / 1 Polymer E6: Mw = 13,000, n / m = 19 / 1 Polymer E7: Mw = 14,000, n / m = 29 / 1 Polymer E8: Mw = 15,000, n / m = 39 / 1 Polymer E9: Mw = 15,000, n / m = 50 / 1 Polymer E10: Mw = 15,000, n / m = 80 / 1

[0105] The structural formulae of polymers C1 to C4 used as specific compounds are shown below. The weight average molecular weight and the content ratio (k / l, molar ratio) of repeating unit A and repeating unit B for each polymer are also shown below.

[0106]

[0107] Polymer C1: k / l = 8 / 2 Polymer C2: k / l = 9 / 1 Polymer C3: Mw = 31,000, k / l = 19 / 1 Polymer C4: Mw = 35,000, k / l = 39 / 1

[0108] [Other ingredients] Acetic acid (solvent) Sulfuric acid, deionized water (DIW, solvent) Takesurf A-47-Q (Takemoto Oil & Fat Co., Ltd.) N-(3-aminopropyl)diethanolamine

[0109] [Evaluation] [Solubility] Each of the prepared etching solutions was evaluated for the solubility of SiGe-containing materials, Si-containing materials, and SiO2-containing materials according to the following procedure. ２ The solubility of the inclusions, SiN-containing substances and SiOCN-containing substances was evaluated according to the following criteria.

[0110] Specifically, first, a substrate on which silicon germanium (Si:Ge=75:25 (element ratio)) is laminated to a thickness of 50 nm, a substrate on which polysilicon (Si) is laminated to a thickness of 100 nm, and a substrate on which silicon oxide (SiO ２ A substrate on which a 100 nm thick SiGe film, a substrate on which a 100 nm thick silicon nitride (SiN) film, and a substrate on which a 100 nm thick silicon oxycarbon nitride (SiOCN) film were laminated were fabricated, and each of these substrates was cut into a 2 x 2 cm square to fabricate test specimens. Each test specimen was immersed in the etching solution (25°C) of the example or comparative example for 2 minutes. Before and after the immersion, the SiGe film, the Si film, and the SiO ２ The thicknesses of the SiN film, SiGe film, and SiOCN film were measured using an optical film thickness meter, Ellipsometer M-2000 (manufactured by J.A. Woollam). The dissolution rate (Å / min) of each film when using each etching solution was calculated from the measured change in film thickness before and after immersion. The solubility of each film in each etching solution was evaluated based on the calculated dissolution rate of each film, according to the following evaluation criteria. The results are shown in Table 1 below. Note that if the evaluation criteria for solubility in a SiGe film are A or B and the evaluation criteria for solubility in a SiOCN film are A or B, it can be said that the etching ability for SiOCN-containing materials is suppressed and the etching ability for SiGe-containing materials is good. <Evaluation criteria for solubility in SiGe film> A: Dissolution rate is 30 Å / min or more B: Dissolution rate is 5 Å / min or more but less than 30 Å / min C: Dissolution rate is less than 5 Å / min <Evaluation criteria for solubility in Si film> A: Dissolution rate is less than 7 Å / min B: Dissolution rate is 7 Å / min or more but less than 15 Å / min C: Dissolution rate is 15 Å / min or more <SiO ２Evaluation criteria for solubility in SiN films> A: Dissolution rate less than 2 Å / min B: Dissolution rate 2 Å / min or more but less than 6 Å / min C: Dissolution rate 6 Å / min or more <Evaluation criteria for solubility in SiN films> A: Dissolution rate less than 1 Å / min B: Dissolution rate 1 Å / min or more but less than 3 Å / min C: Dissolution rate 3 Å / min or more <Evaluation criteria for solubility in SiOCN films> A: Dissolution rate less than 0.1 Å / min B: Dissolution rate 0.1 Å / min or more but less than 0.5 Å / min C: Dissolution rate 0.5 Å / min or more

[0111] [Turbidity] The turbidity of each etching solution prepared by the above procedure was measured using a turbidity meter (TN-100IR manufactured by Thermo Scientific) and evaluated based on the following evaluation criteria. The specific measurement method is as described above.

[0112] (Evaluation criteria) A: Turbidity is less than 5 NTU B: Turbidity is 5 NTU or more and less than 10 NTU C: Turbidity is 10 NTU or more

[0113] [Stability] The stability of the etching solution over time was evaluated based on the presence or absence of precipitation after storage for 1 day and 14 days in an environment of 25° C. The presence or absence of precipitation in the etching solution was confirmed visually.

[0114] [Results] The composition of each etching solution and the evaluation results are shown in the table below. Note that the content of each component in the table is based on mass.

[0115]

[0116] The results shown in Table 1 above indicate that an etching solution that does not contain a specific compound having an acidic group and a basic group cannot suppress the etching ability of an SiOCN-containing material (Comparative Example 1).In contrast, it was found that an etching solution that contains the specific compound suppresses the etching ability of an SiOCN-containing material and exhibits good etching ability of an SiGe-containing material (Examples 1 to 14).

[0117] Furthermore, from a comparison between Examples 9 and 1, it was confirmed that when the compound has a repeating unit A having an acidic group and a repeating unit B having a basic group, and the content ratio B / A, where A mol % is the content of the repeating unit A and B mol % is the content of the repeating unit B relative to all repeating units in the compound, is greater than 2, the turbidity of the etching solution is superior, and from a comparison between Examples 1 to 3 and 9 to 11, it was confirmed that when the content ratio B / A is 5 or more, the turbidity of the etching solution is even superior. From a comparison between Examples 2 to 4 and 12 to 13, it was confirmed that when the content ratio B / A is 35 or less, the solubility of the Si film, SiO ２ It was confirmed that at least one of the solubility of the SiN film and the solubility of the SiOCN film was superior. From a comparison between Examples 13 and 14, it was confirmed that the solubility of the SiN film was superior when the content ratio B / A was 50 or less.

Claims

An etching solution containing a specific compound having an acidic group and a basic group. 　 the specific compound has a repeating unit A having an acidic group and a repeating unit B having a basic group, 2. The etching solution according to claim 1, wherein a content ratio B / A, where A mol % is the content of the repeating unit A relative to all repeating units of the specific compound and B mol % is the content of the repeating unit B relative to all repeating units of the specific compound, is greater than 2 and 50 or less.

3. The etching solution according to claim 2, wherein the content ratio B / A is 5 to 50.

2. The etching solution according to claim 1, wherein the specific compound has a weight average molecular weight of 5,000 to 30,000. 　 The etching solution according to claim 1 , wherein the specific compound has an acidic group capable of dissociating in the etching solution in an amount of 1% or more. 　 The etching solution according to claim 2 , wherein the repeating unit A is a repeating unit having a sulfonic acid group.

3. The etching solution according to claim 2, wherein the repeating unit B is a repeating unit having at least one group selected from the group consisting of a tertiary amino group and a quaternary ammonium salt group. 　 The etching solution according to claim 2 , wherein the repeating unit B has a quaternary ammonium salt group. 　 The etching solution of claim 1 , wherein the etching solution comprises an etchant compound. 　 The etching solution of claim 9 , wherein the etchant compound comprises a source of fluoride ions. 　 The etching solution according to claim 10, wherein the content of the specific compound is 0.001 to 0.3 mass % with respect to the total mass of the etching solution.

10. The etching solution of claim 1 applied to a substrate having silicon oxycarbonitride inclusions.

10. The etching solution of claim 1 applied to a substrate having silicon germanium content.

10. The etching solution of claim 1 applied to a substrate having silicon oxycarbonitride content and silicon germanium content. 　 A method for treating a substrate, comprising contacting a substrate having a silicon oxycarbon nitride-containing material and a silicon germanium-containing material with the etching solution according to any one of claims 1 to 14, and removing at least a portion of the silicon germanium-containing material contained in the substrate. 　 A method for manufacturing a semiconductor device, using the etching solution according to any one of claims 1 to 14.

Images