Composition, and semiconductor substrate manufacturing method and etching method using same

Abstract

Provided is a composition capable of selectively removing silicon while suppressing damage to silicon oxide. This composition contains: a quaternary ammonium compound; and at least one cationic surfactant selected from the group consisting of an aryl group-containing cationic surfactant and a heteroaryl group-containing cationic surfactant.

Description

Composition, and method for manufacturing and etching semiconductor substrate using the same

[0001] The present invention relates to a composition, and a method for producing and etching a semiconductor substrate using the same.

[0002] 2. Description of the Related Art In recent years, electronic devices have become smaller and more functional, and this has led to a demand for smaller and more functional semiconductor substrates.

[0003] For example, in the gate electrode constituting the semiconductor substrate of a metal oxide semiconductor field effect transistor (MOSFET), a combination of silicon oxide and polysilicon has conventionally been used for the gate insulating film and gate electrode. However, in recent years, from the viewpoint of realizing high-speed operation and low power consumption, a combination of a high dielectric constant (High-k) insulator and a metal gate is being preferably adopted for the gate insulating film and gate electrode.

[0004] Known methods for manufacturing semiconductor substrates having such high dielectric constant (High-k) insulators and metal gates include the "gate-first method," in which the gate electrode is formed before the source / drain formation, and the "gate-last method," in which the gate electrode is formed after the source / drain formation. Of these, the gate-last method is preferably adopted because it is easier to obtain desired transistor characteristics.

[0005] In the gate-last method, for example, a semiconductor substrate is manufactured by the following method. First, a sacrificial insulating film made of silicon oxide and a sacrificial gate electrode made of polysilicon are formed, followed by impurity implantation and high-temperature annealing to form extension regions. Next, insulating sidewalls are formed, followed by impurity implantation and high-temperature annealing to form source / drain regions. After silicide is formed on the source / drain surfaces, an interlayer insulating film is deposited. Next, the sacrificial gate electrode made of polysilicon is selectively removed, followed by selectively removing at least a portion of the sacrificial insulator made of silicon oxide. Because the sacrificial insulator is very thin (e.g., 5 nm or less), removing the sacrificial gate electrode and the sacrificial insulator separately according to their purpose can prevent adverse effects on surrounding regions. By depositing a high-k insulator in the removed sacrificial insulator region and a metal gate in the removed sacrificial gate electrode region, respectively, a semiconductor substrate having a high-k insulator and a metal gate can be manufactured.

[0006] Thus, in the manufacture of a semiconductor substrate, when the substrate contains a silicon region containing silicon and a silicon oxide region containing silicon oxide, for example, when the substrate contains a sacrificial gate electrode made of polysilicon and a sacrificial insulating film made of silicon oxide, a method is needed to selectively remove silicon while suppressing damage to the silicon oxide.

[0007] As a method for selectively removing silicon, for example, Patent Document 1 describes an invention relating to an etching solution. The etching solution contains water, at least one quaternary ammonium hydroxide compound, optionally at least one alkanolamine compound, at least one water-miscible organic solvent, a specific nitrogen-containing compound, and optionally a surfactant. In this regard, Patent Document 1 describes that the etching solution is suitable for selectively removing polysilicon over silicon oxide from microelectronic devices.

[0008] Japanese Patent Application Laid-Open No. 2020-88391

[0009] In this situation, a new method is needed that can selectively remove silicon while suppressing damage to silicon oxide.

[0010] The present invention includes, for example, the following aspects.

[0011] [1] A composition comprising a quaternary ammonium compound and at least one cationic surfactant selected from the group consisting of aryl group-containing cationic surfactants and heteroaryl group-containing cationic surfactants. [2] The aryl group-containing cationic surfactant is represented by the following formula (1): [In the formula, R １ is a substituted or unsubstituted alkyl group having 10 to 30 carbon atoms, and R ２ are each independently a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, A is a single bond or a substituted or unsubstituted alkylene group having 1 to 6 carbon atoms, Ar is a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, and X － is a halide ion, hydroxide ion, sulfate ion, hydrogen sulfate ion, sulfite ion, thiosulfate ion, nitrate ion, phosphate ion, monohydrogen phosphate ion, dihydrogen phosphate ion, carbonate ion, hydrogen carbonate ion, or carboxylate ion. １ [4] The composition according to the above [2], wherein the heteroaryl group-containing cationic surfactant is represented by the following formula (2) or (3): [In the formula, R ３ is a substituted or unsubstituted alkyl group having 10 to 30 carbon atoms, and R ４ is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and R ５ are each independently a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, －is a halide ion, hydroxide ion, sulfate ion, hydrogen sulfate ion, sulfite ion, thiosulfate ion, nitrate ion, phosphate ion, monohydrogen phosphate ion, dihydrogen phosphate ion, carbonate ion, bicarbonate ion, or carboxylate ion. [5] R ３ is a substituted or unsubstituted alkyl group having 14 to 20 carbon atoms. [6] The composition according to any one of [1] to [5] above, further comprising an organic solvent. [7] The composition according to [6] above, wherein the organic solvent comprises at least one selected from the group consisting of alkanolamines, aprotic polar solvents, monoalcohols, and polyhydric alcohols. [8] The composition according to any one of [1] to [7] above, wherein the quaternary ammonium compound comprises tetramethylammonium hydroxide (TMAH). [9] A method for producing a semiconductor substrate, comprising a silicon etching step of contacting a semiconductor substrate comprising a silicon region containing silicon and a silicon oxide region containing silicon oxide with the composition according to any one of [1] to [8] above.

[10] A method for etching a semiconductor substrate, comprising a silicon etching step of contacting a semiconductor substrate comprising a silicon region containing silicon and a silicon oxide region containing silicon oxide with the composition according to any one of [1] to [8] above.

[0012] According to the present invention, a composition and the like are provided that can selectively remove silicon while suppressing damage to silicon oxide.

[0013] 1 is a schematic diagram of a semiconductor substrate (before etching) in a manufacturing process of a MOSFET by the gate-last method.

[0014] Hereinafter, embodiments of the present invention will be described in detail.

[0015] <Composition> The composition according to the present invention contains a quaternary ammonium compound and at least one cationic surfactant selected from the group consisting of aryl group-containing cationic surfactants and heteroaryl group-containing cationic surfactants.

[0016] The composition according to the present invention can selectively remove silicon while suppressing damage to silicon oxide (hereinafter, this may be referred to as high silicon / silicon oxide etching selectivity). Possible reasons for this result include, for example, that the cationic surfactant adsorbs more quickly to the silicon oxide surface than to the silicon surface, thereby making it easier to prevent etching of silicon oxide; or that the π-π interaction of the aryl and / or heteroaryl groups of the cationic surfactant allows the cationic surfactant to stably adsorb to the silicon oxide surface, thereby enhancing the effect of preventing etching of silicon oxide. It should be noted that cases in which the composition according to the present invention exhibits the effects of the present invention for reasons other than those described above are also included within the scope of the present invention.

[0017] [Quaternary Ammonium Compound] The quaternary ammonium compound has the function of removing silicon.

[0018] The quaternary ammonium compound is not particularly limited, but examples thereof include quaternary ammonium compounds represented by the following formula (4).

[0019]

[0020] In the above formula, R ６ are each independently an alkyl group having 1 to 6 carbon atoms or a hydroxyalkyl group having 1 to 6 carbon atoms.

[0021] Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, and a butyl group.

[0022] Examples of the hydroxyalkyl group having 1 to 6 carbon atoms include a hydroxymethyl group, a hydroxyethyl group, and a hydroxypropyl group.

[0023] R ６ is preferably an alkyl group having 1 to 3 carbon atoms or a hydroxyalkyl group having 1 to 3 carbon atoms, more preferably a methyl group, an ethyl group, a hydroxymethyl group or a hydroxyethyl group, further preferably a methyl group or an ethyl group, and particularly preferably a methyl group.

[0024] Specific examples of the quaternary ammonium compound represented by formula (4) include tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, 2-hydroxyethyltrimethylammonium hydroxide (choline), 2-hydroxyethyltriethylammonium hydroxide, 2-hydroxyethyltripropylammonium hydroxide, 2-hydroxypropyltrimethylammonium hydroxide, 2-hydroxypropyltriethylammonium hydroxide, 2-hydroxypropyltripropylammonium hydroxide, dimethylbis(2-hydroxyethyl)ammonium hydroxide, diethylbis(2-hydroxyethyl)ammonium hydroxide, dipropylbis(2-hydroxyethyl)ammonium hydroxide, tris(2-hydroxyethyl)methylammonium hydroxide, tris(2-hydroxyethyl)ethylammonium hydroxide, tris(2-hydroxyethyl)propylammonium hydroxide, tetrakis(2-hydroxyethyl)ammonium hydroxide, and tetrakis(2-hydroxypropyl)ammonium hydroxide. Among these, the quaternary ammonium compound preferably contains at least one of tetramethylammonium hydroxide (TMAH) and tetraethylammonium hydroxide (TEAH), and more preferably contains tetramethylammonium hydroxide (TMAH) from the viewpoint of increasing the amount of silicon etched. The above-mentioned quaternary ammonium compounds may be used alone or in combination of two or more.

[0025] The content of the quaternary ammonium compound is preferably 0.1 to 20 mass%, more preferably 0.2 to 10 mass%, even more preferably 0.5 to 5 mass%, still more preferably 0.8 to 3 mass%, and particularly preferably 1 to 2.5 mass%, relative to the total mass of the composition.

[0026] [Cationic Surfactant] The cationic surfactant has the function of improving the silicon / silicon oxide etching selectivity of the composition according to the present invention.

[0027] The cationic surfactant is at least one cationic surfactant selected from the group consisting of aryl group-containing cationic surfactants and heteroaryl group-containing cationic surfactants. The cationic surfactant has properties that make it easy to introduce into the semiconductor substrate manufacturing process. Specifically, when the cationic surfactant is adsorbed onto a semiconductor substrate, such as a silicon oxide film, it can be removed by heating. For example, in the semiconductor substrate manufacturing process, steps (e.g., chemical vapor adsorption (CVD), ashing, dry etching, etc.) performed after silicon etching removal using the composition can be performed under high-temperature conditions, thereby removing the cationic surfactant that may remain during the process. Furthermore, since the cationic surfactant contains an aryl group and a heteroaryl group, it can absorb ultraviolet and visible light (e.g., near-ultraviolet light of 250 to 300 nm). Therefore, the cationic surfactant contained in the manufactured composition can be detected by liquid chromatography using a reverse-phase column, an ultraviolet-visible spectrophotometer, or the like, facilitating analysis of the concentration of the cationic surfactant in the composition.

[0028] (Aryl Group-Containing Cationic Surfactant) The aryl group-containing cationic surfactant is not particularly limited, but is preferably an aryl group-containing cationic surfactant represented by the following formula (1).

[0029]

[0030] In the above formula, R １ is a substituted or unsubstituted alkyl group having 10 to 30 carbon atoms.

[0031] Examples of the alkyl group having 10 to 30 carbon atoms include, but are not limited to, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, and an icosyl group.

[0032] The alkyl group having 10 to 30 carbon atoms may have a substituent. Examples of the substituent include, but are not limited to, an alkoxy group having 1 to 6 carbon atoms, such as a methoxy, ethoxy, or propyloxy group; a hydroxy group; a cyano group; and a nitro group. The alkyl group may have one or more substituents.

[0033] R １ is preferably a substituted or unsubstituted alkyl group having 10 to 20 carbon atoms, and from the viewpoint of increasing silicon / silicon oxide etching selectivity, is more preferably a substituted or unsubstituted alkyl group having 10 to 15 carbon atoms, is further preferably a dodecyl group, a tridecyl group, a tetradecyl group, or a pentadecyl group, and is particularly preferably a tridecyl group, a tetradecyl group, or a pentadecyl group.

[0034] R ２ are each independently a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms.

[0035] The alkyl group having 1 to 6 carbon atoms is not particularly limited, but examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, and a butyl group.

[0036] The alkyl group having 1 to 6 carbon atoms may have a substituent. Examples of the substituent include, but are not limited to, an alkoxy group having 1 to 6 carbon atoms, such as a methoxy, ethoxy, or propyloxy group; a hydroxy group; a cyano group; and a nitro group. The alkyl group may have one or more substituents.

[0037] R ２ is preferably a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, more preferably a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms, further preferably a methyl group or an ethyl group, and particularly preferably a methyl group.

[0038] A is a single bond or a substituted or unsubstituted alkylene having 1 to 6 carbon atoms.

[0039] The alkylene having 1 to 6 carbon atoms is not particularly limited, but examples thereof include methylene, ethylene, propylene, isopropylene, and butylene.

[0040] The alkylene having 1 to 6 carbon atoms may have a substituent. Examples of the substituent include, but are not limited to, an alkoxy group having 1 to 6 carbon atoms, such as a methoxy, ethoxy, or propyloxy group; a hydroxy group; a cyano group; and a nitro group. The alkylene may have one or more substituents.

[0041] A is preferably a single bond, or a substituted or unsubstituted alkylene having 1 to 4 carbon atoms, more preferably a single bond, or a substituted or unsubstituted alkylene having 1 to 3 carbon atoms, still more preferably a single bond, methylene, or ethylene, and particularly preferably methylene.

[0042] Ar is a substituted or unsubstituted aryl group having 6 to 30 carbon atoms.

[0043] The aryl group having 6 to 30 carbon atoms is not particularly limited, but examples thereof include a phenyl group, a naphthyl group, and an anthracenyl group.

[0044] The aryl group having 6 to 30 carbon atoms may have a substituent. Examples of the substituent include, but are not limited to, alkyl groups having 1 to 10 carbon atoms such as methyl, ethyl, propyl, isopropyl, and butyl; alkoxy groups having 1 to 6 carbon atoms such as methoxy, ethoxy, and propyloxy; hydroxy groups; cyano groups; and nitro groups. The number of substituents may be one or more.

[0045] Ar is preferably a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, more preferably a substituted or unsubstituted phenyl group or a substituted or unsubstituted naphthyl group, still more preferably a substituted or unsubstituted phenyl group, and particularly preferably a phenyl group.

[0046] X －is a halide ion (fluoride ion, chloride ion, bromide ion, iodide ion), hydroxide ion, sulfate ion, hydrogen sulfate ion, sulfite ion, thiosulfate ion, nitrate ion, phosphate ion, monohydrogen phosphate ion, dihydrogen phosphate ion, carbonate ion, hydrogen carbonate ion, or carboxylate ion. － is preferably a halide ion or a hydroxide ion, more preferably a halide ion, further preferably a chloride ion or a bromide ion, and particularly preferably a chloride ion.

[0047] Specific examples of aryl group-containing cationic surfactants include benzyl dimethyl decyl ammonium chloride, benzyl dimethyl dodecyl ammonium chloride, benzyl dimethyl tetradecyl ammonium chloride (BDMTDA), benzyl dimethyl hexadecyl ammonium chloride (BDMHDA), benzyl dimethyl octadecyl ammonium chloride, benzyl dimethyl decyl ammonium bromide, benzyl dimethyl dodecyl ammonium bromide, benzyl dimethyl tetradecyl ammonium bromide, and benzyl dimethyl hexadecyl ammonium chloride. ammonium bromide, benzyldimethyloctadecylammonium bromide, benzyldiethyldecylammonium chloride, benzyldiethyldodecylammonium chloride, benzyldiethyltetradecylammonium chloride, benzyldiethylhexadecylammonium chloride, benzyldiethyloctadecylammonium chloride, benzylethylmethyldecylammonium chloride, benzylethylmethyldodecylammonium chloride, benzylethylmethyltetradecylammonium chloride, benzylethylmethylhexadecylammonium ammonium chloride, benzylethylmethyloctadecylammonium chloride, dimethylphenyldecylammonium chloride, dimethylphenyldodecylammonium chloride, dimethylphenyltetradecylammonium chloride, dimethylphenylhexadecylammonium chloride, dimethylphenyloctadecylammonium chloride, diethylphenyldecylammonium chloride, diethylphenyldodecylammonium chloride, diethylphenyltetradecylammonium chloride, diethylphenylhexadecylammonium chloride, diethylphenyloctadecylammonium chloride, ethylmethylphenyldecylammonium chloride, ethylmethylphenyldodecylammonium chloride, ethylmethylphenyltetradecylammonium chloride, ethylmethylphenylhexadecylammonium chloride, ethylmethylphenyloctadecylammonium chloride, dimethylnaphthyldecylammonium chloride, dimethylnaphthyldodecylammonium chloride, dimethylnaphthyltetradecylammonium chloride, dimethylnaphthylhexadecylammonium chloride,Examples of the ammonium chloride include dimethyl naphthyloctadecyl ammonium chloride, diethyl naphthyldecyl ammonium chloride, diethyl naphthyldodecyl ammonium chloride, diethyl naphthyltetradecyl ammonium chloride, diethyl naphthylhexadecyl ammonium chloride, diethyl naphthyloctadecyl ammonium chloride, ethyl methyl naphthyldecyl ammonium chloride, ethyl methyl naphthyldodecyl ammonium chloride, ethyl methyl naphthyltetradecyl ammonium chloride, ethyl methyl naphthylhexadecyl ammonium chloride, and ethyl methyl naphthyloctadecyl ammonium chloride. Among these, the aryl group-containing cationic surfactants are benzyl dimethyl dodecyl ammonium chloride, benzyl dimethyl tetradecyl ammonium chloride (BDMTDA), benzyl dimethyl hexadecyl ammonium chloride (BDMHDA), benzyl dimethyl dodecyl ammonium bromide, benzyl dimethyl tetradecyl ammonium bromide, benzyl dimethyl hexadecyl ammonium bromide, benzyl diethyl dodecyl ammonium chloride, benzyl diethyl tetradecyl ammonium chloride, benzyl diethyl hexadecyl ammonium chloride, benzyl ethyl methyl dodecyl ammonium chloride, benzyl ethyl methyl tetradecyl ammonium chloride, and benzyl ethyl methyl hexadecyl ammonium chloride. are preferred, benzyl dimethyl dodecyl ammonium chloride, benzyl dimethyl tetradecyl ammonium chloride (BDMTDA), benzyl dimethyl dodecyl ammonium bromide, benzyl dimethyl tetradecyl ammonium bromide, benzyl diethyl dodecyl ammonium chloride, benzyl diethyl tetradecyl ammonium chloride, benzyl ethyl methyl dodecyl ammonium chloride, and benzyl ethyl methyl tetradecyl ammonium chloride are more preferred, and benzyl dimethyl tetradecyl ammonium chloride (BDMTDA), benzyl dimethyl tetradecyl ammonium bromide, benzyl diethyl tetradecyl ammonium chloride, and benzyl ethyl methyl tetradecyl ammonium chloride are even more preferred.

[0048] (Heteroaryl Group-Containing Cationic Surfactant) The heteroaryl group-containing cationic surfactant is not particularly limited, but is preferably a heteroaryl group-containing cationic surfactant represented by the following formula (2) or (3).

[0049]

[0050] In the above formula, R ３ is a substituted or unsubstituted alkyl group having 10 to 30 carbon atoms. In this case, the substituted or unsubstituted alkyl group having 10 to 30 carbon atoms is １ Among these, R ３ is preferably a substituted or unsubstituted alkyl group having 10 to 20 carbon atoms, and from the viewpoint of increasing silicon / silicon oxide etching selectivity, is more preferably a substituted or unsubstituted alkyl group having 14 to 20 carbon atoms, is further preferably a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, or an icosyl group, and is particularly preferably a tetradecyl group, a pentadecyl group, a hexadecyl group, or a heptadecyl group.

[0051] R ４ is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms. In this case, the substituted or unsubstituted alkyl group having 1 to 6 carbon atoms is the same as the above R ２ Among these, R ４ is preferably a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, more preferably a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms, further preferably a methyl group or an ethyl group, and particularly preferably a methyl group.

[0052] R ５ are each independently a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms. In this case, the substituted or unsubstituted alkyl group having 1 to 6 carbon atoms is ２ Among these, R ５is preferably a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom, a methyl group, or an ethyl group, even more preferably a hydrogen atom or a methyl group, and particularly preferably a hydrogen atom.

[0053] X － is a halide ion, hydroxide ion, sulfate ion, hydrogen sulfate ion, sulfite ion, thiosulfate ion, nitrate ion, phosphate ion, monohydrogen phosphate ion, dihydrogen phosphate ion, carbonate ion, hydrogen carbonate ion, or carboxylate ion. － is the same as that described in the above formula (1).

[0054] Specific examples of heteroaryl group-containing cationic surfactants include 1-dodecyl-3-methylimidazolium chloride (DMI), 1-tetradecyl-3-methylimidazolium chloride, 1-hexadecyl-3-methylimidazolium chloride (HDMI), 1-octadecyl-3-methylimidazolium chloride, 1-dodecyl-3-methylimidazolium bromide, 1-tetradecyl-3-methylimidazolium bromide, 1-hexadecyl-3-methylimidazolium bromide, 1-octadecyl-3-methylimidazolium bromide, 1-dodecyl-3-ethylimidazolium chloride, 1-tetradecyl-3-ethylimidazolium chloride, 1-hexadecyl-3-ethylimidazolium chloride, and 1-octadecyl-3-ethylimidazolium chloride. Imidazolyl group-containing cationic surfactants represented by formula (2): 1-dodecyl-3-methylpyrazolyl chloride, 1-tetradecyl-3-methylpyrazolyl chloride, 1-hexadecyl-3-methylpyrazolyl chloride, 1-octadecyl-3-methylpyrazolyl chloride, 1-dodecyl-3-methylpyrazolyl bromide, 1-tetradecyl-3-methylpyrazolyl bromide, 1-hexadecyl-3-methylpyrazolyl bromide, 1-octadecyl-3-methylpyrazolyl bromide, 1-dodecyl-3-ethylpyrazolyl chloride, 1-tetradecyl-3-ethylpyrazolyl chloride, 1-hexadecyl-3-ethylpyrazolyl chloride, 1-octadecyl-3-ethylpyrazolyl chloride, and the like.Among these, the heteroaryl group-containing cationic surfactant is preferably an imidazolyl group-containing cationic surfactant represented by formula (2), and examples thereof include 1-tetradecyl-3-methylimidazolium chloride, 1-hexadecyl-3-methylimidazolium chloride (HDMI), 1-octadecyl-3-methylimidazolium chloride, 1-tetradecyl-3-methylimidazolium bromide, 1-hexadecyl-3-methylimidazolium bromide, and 1-octadecyl-3-methylimidazolium chloride. Tadecyl-3-methylimidazolium bromide, 1-tetradecyl-3-ethylimidazolium chloride, 1-hexadecyl-3-ethylimidazolium chloride, and 1-octadecyl-3-ethylimidazolium chloride are more preferred, and 1-hexadecyl-3-methylimidazolium chloride (HDMI), 1-hexadecyl-3-methylimidazolium bromide, and 1-hexadecyl-3-ethylimidazolium chloride are even more preferred.

[0055] The above-mentioned cationic surfactants may be used alone or in combination of two or more kinds.

[0056] The content of the cationic surfactant is preferably 0.00001 to 1 mass %, more preferably 0.0001 to 1 mass %, and even more preferably 0.001 to 0.5 mass %, relative to the total mass of the composition. From the viewpoint of increasing silicon / silicon oxide etching selectivity, the content is particularly preferably 0.008 to 0.5 mass %, and most preferably 0.01 to 0.04 mass %.

[0057] [Other Surfactants] The composition of the present invention may further contain other surfactants. Examples of other surfactants include other cationic surfactants, anionic surfactants, nonionic surfactants, and amphoteric surfactants.

[0058] The other cationic surfactant is a cationic surfactant other than the above-mentioned aryl group-containing cationic surfactant and heteroaryl group-containing cationic surfactant.The other cationic surfactant is not particularly limited, but includes decyltrimethylammonium chloride, dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, octadecyltrimethylammonium chloride, decyltrimethylammonium bromide, dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide (HDTMA), octadecyltrimethylammonium bromide, decyltriethylammonium chloride, dodecyltriethylammonium chloride, tetradecyltriethylammonium bromide (HDTMA), octadecyltrimethylammonium bromide, decyltriethylammonium chloride, dodecyltriethylammonium chloride, tetradecyltriethylammonium bromide, tetradecyltriethylammonium bromide (HDTMA), octadecyltrimethylammonium bromide, decyltriethylammonium chloride, dodecyltriethylammonium chloride, tetradecyltriethylammonium bromide, tetradecyltriethylammonium bromide (HDTMA), octadecyltrimethylammonium bromide, decyltriethylammonium chloride, tetradecyltriethylammonium bromide ... Examples of the ammonium chloride include decyl ammonium chloride, hexadecyl triethyl ammonium chloride, octadecyl triethyl ammonium chloride, decyl dimethyl ethyl ammonium chloride, dodecyl dimethyl ethyl ammonium chloride, tetradecyl dimethyl ethyl ammonium chloride, hexadecyl dimethyl ethyl ammonium chloride, octadecyl dimethyl ethyl ammonium chloride, decyl diethyl methyl ammonium chloride, dodecyl diethyl methyl ammonium chloride, tetradecyl diethyl methyl ammonium chloride, hexadecyl diethyl methyl ammonium chloride, and octadecyl diethyl methyl ammonium chloride.

[0059] Examples of anionic surfactants include, but are not limited to, alkyl sulfates such as sodium decylbenzenesulfonate, sodium decylbenzenesulfonate, sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium hexadecyl sulfate, and sodium octadecyl sulfate; alkyl benzene sulfonates such as sodium decylbenzenesulfonate, sodium dodecylbenzenesulfonate, sodium tetradecylbenzenesulfonate, sodium hexadecylbenzenesulfonate, and sodium octadecylbenzenesulfonate; and alkyl polyoxyethylene sulfates such as polyoxyethylene decyl ether sodium sulfate, polyoxyethylene dodecyl ether sodium sulfate, polyoxyethylene tetradecyl ether sodium sulfate, polyoxyethylene hexadecyl ether sodium sulfate, and polyoxyethylene octadecyl ether sodium sulfate.

[0060] Examples of nonionic surfactants include, but are not limited to, glycerin fatty acid esters such as glycerin caprate, glycerin laurate, glycerin myristate, glycerin palmitate, and glycerin stearate; and polyoxyethylene ether fatty acid esters such as polysorbate 20 (Tween 20), polysorbate 60 (Tween 60), and polysorbate 80 (Tween 80).

[0061] The amphoteric surfactant is not particularly limited, but examples thereof include cocamidopropyl betaine, cocamidopropyl hydroxysultaine, and ethylene oxide alkylamine.

[0062] The above-mentioned other surfactants may be used alone or in combination of two or more.

[0063] [Acidic Compound] The composition of the present invention may contain an acidic compound, which has the function of adjusting the pH of the composition.

[0064] The acidic compound is not particularly limited, but includes inorganic acidic compounds and organic acidic compounds.

[0065] The inorganic acidic compound is not particularly limited, but examples thereof include hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, and phosphoric acid.

[0066] The organic acidic compound is not particularly limited, but examples thereof include methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, acetic acid, citric acid, and lactic acid.

[0067] The above-mentioned acidic compounds may be used alone or in combination of two or more. The amount of the acidic compound added is preferably an amount that allows the pH of the composition to reach the desired value.

[0068] [Water] The composition may contain water. Water has a function of dispersing the quaternary ammonium compound, the cationic surfactant, etc. In a preferred embodiment, the composition contains water.

[0069] The water content is preferably 10 to 99.9% by mass, more preferably 15 to 99% by mass, based on the total mass of the composition.

[0070] [Organic Solvent] The composition according to the present invention may contain an organic solvent. The solvent has the function of dispersing the quaternary ammonium compound, the cationic surfactant, etc., and the function of improving the silicon / silicon oxide etching selectivity of the composition according to the present invention. In a preferred embodiment, the composition preferably further contains an organic solvent.

[0071] The organic solvent is not particularly limited, but examples thereof include alkanolamines, aprotic polar solvents, monoalcohols, polyhydric alcohols, ethers, glycol ethers, and the like.

[0072] The alkanolamine is not particularly limited, but examples thereof include monomethanolamine, monoethanolamine (MEA), N-methylethanolamine, N-ethylethanolamine, N-cyclohexylethanolamine, N-(2-aminoethyl)ethanolamine, O-(2-hydroxyethyl)ethanolamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, diethanolamine, N-methyldiethanolamine, N-ethyldimethanolamine, diisopropanolamine, triethanolamine, and triisopropanolamine.

[0073] The aprotic polar solvent is not particularly limited, but examples thereof include dimethyl sulfoxide (DMSO), dimethylformamide (DMA), diethylformamide (DEA), dimethylacetamide, N-methylpyrrolidone, acetonitrile, and hexamethylphosphoric triamide.

[0074] The monoalcohol is not particularly limited, but examples thereof include methanol, ethanol, propanol, isopropyl alcohol (IPA), 1-butanol, tert-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, and 1-decanol.

[0075] The polyhydric alcohol is not particularly limited, and examples thereof include ethylene glycol (EG), propylene glycol, neopentyl glycol, 1,2-hexanediol, 1,6-hexanediol, 2-ethylhexane-1,3-diol, glycerin, etc. In this specification, "polyhydric" means divalent or higher, preferably divalent, trivalent, or tetravalent, more preferably divalent or trivalent, and even more preferably divalent.

[0076] The ether is not particularly limited, but examples thereof include dimethyl ether, diethyl ether, tetrahydrofuran, and 1,4-dioxane.

[0077] The glycol ether is not particularly limited, but examples thereof include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol n-butyl ether (2-butoxyethanol), ethylene glycol monophenyl ether (phenyl glycol), propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol n-propyl ether, propylene glycol n-butyl ether, propylene glycol phenyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monophenyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol n-propyl ether, dipropylene glycol n-butyl ether, tripropylene glycol monomethyl ether, tripropylene glycol n-propyl ether, tripropylene glycol n-butyl ether, and dipropylene glycol dimethyl ether.

[0078] Of these, the organic solvent preferably contains at least one selected from the group consisting of alkanolamines, aprotic polar solvents, monoalcohols, and polyhydric alcohols, more preferably contains at least one selected from the group consisting of alkanolamines, aprotic polar solvents, and polyhydric alcohols, and from the viewpoint of increasing silicon / silicon oxide etching selectivity, it is even more preferable that it contains at least one selected from the group consisting of alkanolamines and aprotic polar solvents, even more preferably contains an alkanolamine, particularly preferably contains at least one selected from the group consisting of monomethanolamine, monoethanolamine (MEA), N-methylethanolamine, N-ethylethanolamine, N-cyclohexylethanolamine, N-(2-aminoethyl)ethanolamine, O-(2-hydroxyethyl)ethanolamine, N,N-dimethylethanolamine, and N,N-diethylethanolamine, and most preferably contains at least one selected from monomethanolamine and monoethanolamine (MEA). In one embodiment, the organic solvent preferably contains at least one selected from the group consisting of monomethanolamine, monoethanolamine (MEA), dimethyl sulfoxide (DMSO), methanol, ethanol, propanol, isopropyl alcohol (IPA), ethylene glycol (EG), and propylene glycol; more preferably contains at least one selected from monoethanolamine (MEA), dimethyl sulfoxide (DMSO), isopropyl alcohol (IPA), and ethylene glycol (EG); still more preferably contains at least one selected from monoethanolamine (MEA), dimethyl sulfoxide (DMSO), and ethylene glycol (EG); from the viewpoint of increasing silicon / silicon oxide etching selectivity, it is particularly preferable that the organic solvent contains at least one selected from monoethanolamine (MEA) and dimethyl sulfoxide (DMSO), and most preferably contains monoethanolamine (MEA).

[0079] The organic solvents described above may be used alone or in combination of two or more kinds.

[0080] The content of the organic solvent is preferably 5 to 90 mass %, more preferably 15 to 85 mass %, relative to the total mass of the composition. From the viewpoint of increasing silicon / silicon oxide etching selectivity, the content is further preferably 40 to 80 mass %, and particularly preferably 55 to 75 mass %.

[0081] In one embodiment, the total solvent content of the composition is preferably 80 to 99.9% by mass, more preferably 85 to 99.5% by mass, and even more preferably 90 to 99% by mass, relative to the total mass of the composition. In this specification, the term "total solvent content" refers to the water content when the composition contains only water as a solvent, the organic solvent content when the composition contains only an organic solvent as a solvent, and the combined content of water and organic solvent when the composition contains both water and an organic solvent as solvents.

[0082] [Physical Properties of Composition] The pH of the composition according to the present invention is preferably 8 or higher, more preferably 10 or higher, even more preferably 13 or higher, particularly preferably 13 to 16, and most preferably 13 to 14. A pH of 8 or higher is preferred because it increases the silicon / silicon oxide etching selectivity. When the pH of the composition is 8 or higher, i.e., when the composition is basic, a difference in the surface potential (ζ potential) of silicon and silicon oxide may occur when the composition comes into contact. Specifically, since the silicon oxide surface has more silanol groups (—SiOH) than the silicon surface, under basic conditions, protons are lost from the silanol groups, resulting in the formation of (—SiO ― ), the surface of the silicon oxide has more negative charges, which makes it easier for the cationic surfactant contained in the composition to adsorb to the silicon oxide surface, potentially increasing the silicon / silicon oxide etching selectivity.

[0083] The silicon etching rate of the composition according to the present invention is not particularly limited, but is preferably 50 Å / min or more, more preferably 80 to 500 Å / min, even more preferably 120 to 400 Å / min, and particularly preferably 150 to 300 Å / min. A silicon etching rate of 50 Å / min or more is preferred because it provides excellent production efficiency. The silicon etching rate can be calculated from the amount etched per 30 seconds measured using the method in the Examples.

[0084] The etching rate of silicon oxide of the composition according to the present invention is not particularly limited, but is preferably 30×10 －３ Å / min or less, and preferably 10×10 －３ More preferably, it is 1×10 Å / min or less. －３ The etching rate of silicon oxide is particularly preferably 1×10 Å / min or less. －６ Å / min or more, 1×10 －５ Å / min or more.

[0085] The silicon / silicon oxide etching selectivity of the composition according to the present invention is not particularly limited, but is preferably 10,000 or more, more preferably 20,000 or more, even more preferably 40,000 or more, particularly preferably 100,000 or more, and may be 200,000 or more, 220,000 or more, or 250,000 or more. The upper limit of the silicon / silicon oxide etching selectivity is not particularly limited, but is, for example, 1,000,000 or less or 800,000 or less. In this specification, "silicon / silicon oxide etching selectivity" means the ratio of the silicon etching rate (Å / min) to the silicon oxide etching rate (Å / min) (silicon etching rate / silicon oxide etching rate).

[0086] [Uses] The composition according to the present invention is suitable for use in the manufacture of semiconductor substrates. The structure of the semiconductor substrate is not particularly limited, and may be any of MOS, bipolar, and BiCMOS types. The semiconductor substrate can also be used in semiconductor devices such as diodes, solar cells, DRAMs, flash memory logic, sensors, actuators, and converters.

[0087] <Method for manufacturing a semiconductor substrate> According to one aspect of the present invention, there is provided a method for manufacturing a semiconductor substrate, which includes a silicon etching step of contacting a semiconductor substrate including a silicon region containing silicon and a silicon oxide region containing silicon oxide with the composition described above.

[0088] Examples of silicon include, but are not limited to, polysilicon, amorphous silicon, and single-crystal silicon. In this case, polysilicon or amorphous silicon is preferred, and polysilicon is more preferred. In this specification, "silicon" refers to a compound containing 80 at% or more, preferably 90 at% or more, and more preferably 95 to 100 at% silicon (Si) atoms. In this case, the silicon may further contain at least one atom selected from the group consisting of phosphorus (P), boron (B), and arsenic (As). In this specification, the atomic content (at%) in a compound can be determined by measuring the atomic content of the target atom using ion sputtering by X-ray photoelectron spectroscopy (XPS). For example, when measuring the atomic content of silicon (Si) atoms in silicon, the atomic content of silicon (Si) atoms near the surface of the silicon may be lower than the interior of the material due to oxidation or carbon contamination. Therefore, the surface of the silicon is etched by ion sputtering until the atomic content of silicon (Si) atoms becomes constant, and the atomic content of silicon (Si) atoms inside the silicon exposed by ion sputtering can be measured.

[0089] Furthermore, silicon oxide is not particularly limited, but examples include silicon oxide, tetraethoxysilane (TEOS), borophosphosilicate glass (BPSG), borosilicate glass (BSG), phosphosilicate glass (PSG), etc. In this specification, "silicon oxide" means a compound containing a total of 60 at% or more, preferably 70 at% or more, and more preferably 75 to 100 at% of silicon (Si) atoms and oxygen (O) atoms, and containing less than 50 at%, preferably 40 at% or less, and more preferably 15 to 35 at% of silicon (Si) atoms.

[0090] Here, the configuration of the semiconductor substrate is not particularly limited as long as it includes a silicon region containing silicon and a silicon oxide region containing silicon oxide in the manufacturing process, and may be any of a MOS type, a bipolar type, and a BiCMOS type. Among these, the configuration of the semiconductor substrate is preferably a MOS type. For example, a MOSFET shown in FIG. 1 is an example of a semiconductor substrate including a silicon region containing silicon and a silicon oxide region containing silicon oxide.

[0091] FIG. 1 is a schematic diagram of a semiconductor substrate (before etching) during the gate-last MOSFET manufacturing process. The semiconductor substrate (before etching) 10 includes a silicon substrate 11 on which a sacrificial insulating film (silicon oxide region) 12 made of silicon oxide, a sacrificial gate electrode (silicon region) 13 made of polysilicon, and insulating sidewalls 14 are formed. The silicon substrate 11 also includes an isolation film 15 that defines a MOS region. The silicon substrate 11 also includes an extension region 16 formed by impurity implantation and high-temperature annealing, a source / drain region 17 formed by impurity implantation and high-temperature annealing, and a silicide region 18 formed by silicidation. An insulating film 19 is formed on the silicon substrate 11 in regions other than the sacrificial insulating film (silicon oxide region) 12, the sacrificial gate electrode (silicon region) 13, and the insulating sidewalls 14. Such a semiconductor substrate can be manufactured by any known technique.

[0092] In one embodiment, silicon in a silicon region containing silicon is etched by contacting a semiconductor substrate with a composition according to the present invention. For example, by treating a semiconductor substrate (before etching) 10 shown in FIG. 1 with a composition according to the present invention, a sacrificial gate electrode (silicon region) 13 made of polysilicon is selectively etched. During this process, the sacrificial insulating film (silicon oxide region) 12 made of silicon oxide is hardly etched. Even when the sacrificial gate electrode (silicon region) 13 made of polysilicon is etched, the sacrificial insulating film (silicon oxide region) 12 remains, so that, for example, the contact surface between the silicon substrate 11 and the sacrificial insulating film (silicon oxide region) 12 shown in FIG. 1 is not corroded.

[0093] The contact method in the silicon etching step is not particularly limited, and the semiconductor substrate may be immersed in the composition, or the composition may be sprayed onto the semiconductor substrate, or may be dropped (single wafer spin treatment, etc.). In this case, the immersion may be repeated two or more times, the spraying may be repeated two or more times, or the dropping may be repeated two or more times, or immersion, spraying, and dropping may be combined.

[0094] The contact temperature in the silicon etching step is not particularly limited, but is preferably 0 to 90°C, more preferably 15 to 80°C, and even more preferably 20 to 70°C.

[0095] The contact time in the silicon etching step is not particularly limited, but is preferably 10 seconds to 3 hours, more preferably 10 seconds to 1 hour, even more preferably 10 seconds to 45 minutes, and particularly preferably 20 seconds to 5 minutes.

[0096] In one embodiment, the method for manufacturing a semiconductor substrate may further include a silicon oxide etching step of contacting a semiconductor substrate including a silicon oxide region containing silicon oxide with an etching solution. For example, in a semiconductor substrate from which a sacrificial gate electrode (silicon region) has been removed, the sacrificial insulating film (silicon oxide region) is removed using an etching solution. This exposes, for example, the silicon substrate surface. Note that a portion of the sacrificial insulating film (silicon oxide region) may be left.

[0097] The etching solution used in the silicon oxide etching step is not particularly limited, but examples thereof include a mixture of hydrofluoric acid (HF) and nitric acid, a hydrofluoric acid solution, an acidic ammonium fluoride aqueous solution, and an ammonium fluoride aqueous solution.

[0098] The contact method in the silicon oxide etching step is not particularly limited, and the semiconductor substrate may be immersed in the etching solution, or the etching solution may be sprayed onto the semiconductor substrate, or may be dropped (single wafer spin treatment, etc.). In this case, the immersion may be repeated two or more times, the spraying may be repeated two or more times, or the dropping may be repeated two or more times, or immersion, spraying, and dropping may be combined.

[0099] The contact temperature in the silicon oxide etching step is not particularly limited, but is preferably 0 to 90°C, more preferably 15 to 80°C, and even more preferably 20 to 70°C.

[0100] The contact time in the silicon oxide etching step is not particularly limited, but is preferably 10 seconds to 3 hours, more preferably 10 seconds to 1 hour, even more preferably 10 seconds to 45 minutes, and particularly preferably 20 seconds to 5 minutes.

[0101] In one embodiment, the method for manufacturing a semiconductor substrate may further include a step of forming a high dielectric constant (High-k) insulator and a step of forming a metal gate. For example, a MOSFET can be manufactured by forming a high dielectric constant (High-k) insulator and then forming a metal gate on a semiconductor substrate from which the sacrificial insulating film (silicon oxide region) and the sacrificial gate electrode (silicon region) have been removed.

[0102] The high dielectric constant (High-k) insulator is not particularly limited, but examples thereof include hafnium silicate, zirconium silicate, hafnium oxide, zirconia, lanthanum oxide, tantalum oxide, and aluminum oxide. These high dielectric constant (High-k) insulators may be used alone or in combination of two or more. In this specification, "high dielectric constant" means a relative dielectric constant of 4 or more, preferably 10 or more, and more preferably 20 or more.

[0103] The film formation method in the step of forming a high dielectric constant (High-k) insulator is not particularly limited, and examples thereof include atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), etc. These methods may be used alone or in combination of two or more.

[0104] The metal gate is not particularly limited, but examples thereof include tantalum, tantalum nitride, tantalum nitride silicide, tantalum carbide, tantalum oxide, niobium, tungsten, tungsten nitride, ruthenium oxide, titanium nitride, molybdenum, molybdenum nitride, titanium aluminum, etc. These metal gates may be used alone or in combination of two or more.

[0105] The film formation method in the step of forming the metal gate is not particularly limited, and examples thereof include atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), etc. These methods may be used alone or in combination of two or more.

[0106] <Method for Etching a Semiconductor Substrate> According to one aspect of the present invention, there is provided a method for etching a semiconductor substrate. The method for etching a semiconductor substrate includes a silicon etching step of contacting a semiconductor substrate including a silicon region containing silicon and a silicon oxide region containing silicon oxide with the composition described above. Specific examples of the method for etching a semiconductor substrate are the same as those described above.

[0107] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0108] Example 1: A composition was prepared by mixing tetramethylammonium hydroxide (TMAH), benzyldimethyltetradecylammonium chloride (BDMTDA), and water. The contents of TMAH and BDMTDA were 1.5% by mass and 0.02% by mass, respectively, based on the total mass of the composition. The pH of the composition was measured and found to be 13.4.

[0109] [Example 2] A composition was produced in the same manner as in Example 1, except that benzyldimethylhexadecylammonium chloride (BDMHDA) was used instead of BDMTDA. The pH of the composition was measured in the same manner as in Example 1 and was found to be 13.4.

[0110] [Example 3] A composition was produced in the same manner as in Example 1, except that benzyldimethylhexadecylammonium chloride (BDMHDA) was used instead of BDMTDA and the content of BDMHDA was changed to 0.005% by mass. The pH of the composition was measured in the same manner as in Example 1 and was found to be 13.4.

[0111] Example 4 A composition was produced in the same manner as in Example 1, except that 1-hexadecyl-3-methylimidazolium chloride monohydrate (HDMI) was used instead of BDMTDA. The pH of the composition was measured in the same manner as in Example 1 and was found to be 13.4.

[0112] Example 5 A composition was produced in the same manner as in Example 1, except that 1-hexadecyl-3-methylimidazolium chloride monohydrate (HDMI) was used instead of BDMTDA and the HDMI content was changed to 0.05% by mass. The pH of the composition was measured in the same manner as in Example 1 and was found to be 13.4.

[0113] Example 6 A composition was produced in the same manner as in Example 1, except that 1-dodecyl-3-methylimidazolium chloride (DMI) was used instead of BDMTDA. The pH of the composition was measured in the same manner as in Example 1 and was found to be 13.4.

[0114] Example 7 A composition was produced in the same manner as in Example 1, except that 1-dodecyl-3-methylimidazolium chloride (DMI) was used instead of BDMTDA and the DMI content was changed to 0.05% by mass. The pH of the composition was measured in the same manner as in Example 1 and was found to be 13.4.

[0115] [Example 8] A composition was produced in the same manner as in Example 1, except that tetraethylammonium hydroxide (TEAH) was used instead of TMAH and the content of TEAH was changed to 2 mass%. The pH of the composition was measured in the same manner as in Example 1 and was found to be 13.3.

[0116] [Example 9] A composition was produced in the same manner as in Example 1, except that ethylene glycol (EG) was further added so that the content was 70 mass%. The water content in the composition was 28.48 mass%. The pH of the composition was measured in the same manner as in Example 1 and was found to be 12.9.

[0117] Example 10 A composition was produced in the same manner as in Example 1, except that benzyldimethylhexadecylammonium chloride (BDMHDA) was used instead of BDMTDA and monoethanolamine (MEA) was further added so that the content was 30% by mass. The water content in the composition was 68.48% by mass. The pH of the composition was measured in the same manner as in Example 1 and was found to be 13.9.

[0118] [Example 11] A composition was produced in the same manner as in Example 1, except that benzyldimethylhexadecylammonium chloride (BDMHDA) was used instead of BDMTDA and monoethanolamine (MEA) was further added so that the content was 60 mass%. The water content in the composition was 38.48 mass%. The pH of the composition was measured in the same manner as in Example 1 and was found to be 14.9.

[0119] [Example 12] A composition was produced in the same manner as in Example 1, except that isopropyl alcohol (IPA) was further added so that the content was 10 mass%. The water content in the composition was 88.48 mass%. The pH of the composition was measured in the same manner as in Example 1 and was found to be 13.6.

[0120] [Example 13] A composition was produced in the same manner as in Example 1, except that benzyldimethylhexadecylammonium chloride (BDMHDA) was used instead of BDMTDA and dimethyl sulfoxide (DMSO) was further added so that the content was 50% by mass. The water content in the composition was 48.48% by mass. The pH of the composition was measured in the same manner as in Example 1 and was found to be 15.4.

[0121] [Comparative Example 1] A composition was produced in the same manner as in Example 1, except that benzyldimethyltetradecylammonium chloride (BDMTDA) was not added. The water content in the composition was 98.5 mass%. The pH of the composition was measured in the same manner as in Example 1 and was found to be 13.6.

[0122] [Comparative Example 2] A composition was produced in the same manner as in Example 8, except that benzyldimethyltetradecylammonium chloride (BDMTDA) was not added. The water content in the composition was 98% by mass. The pH of the composition was measured in the same manner as in Example 1 and was found to be 13.3.

[0123] [Comparative Example 3] A composition was produced in the same manner as in Comparative Example 1, except that ethylene glycol (EG) was further added so that the content was 70 mass%. The water content in the composition was 28.5 mass%. The pH of the composition was measured in the same manner as in Example 1 and was found to be 12.9.

[0124] [Comparative Example 4] A composition was produced in the same manner as in Comparative Example 1, except that monoethanolamine (MEA) was further added so that the content was 30 mass%. The water content in the composition was 68.5 mass%. The pH of the composition was measured in the same manner as in Example 1 and was found to be 13.8.

[0125] [Comparative Example 5] A composition was produced in the same manner as in Comparative Example 1, except that isopropyl alcohol (IPA) was further added so that the content was 10 mass %. The water content in the composition was 88.5 mass %. The pH of the composition was measured in the same manner as in Example 1 and was found to be 13.6.

[0126] [Comparative Example 6] A composition was produced in the same manner as in Comparative Example 1, except that dimethyl sulfoxide (DMSO) was further added so that the content was 50 mass %. The water content in the composition was 48.5 mass %. The pH of the composition was measured in the same manner as in Example 1 and was found to be 15.4.

[0127] [Comparative Example 7] A composition was produced in the same manner as in Comparative Example 1, except that the TMAH content was changed to 2% by mass and hexadecyltrimethylammonium bromide (HDTMA) was further added so that the TMAH content became 1% by mass. The water content in the composition was 97% by mass. The pH of the composition was measured in the same manner as in Example 1 and was found to be 13.5.

[0128] The compositions prepared in Examples 1 to 13 and Comparative Examples 1 to 7 are shown in Table 1 below.

[0129]

[0130] The structural formulas of the cationic surfactants used in the examples and comparative examples are as follows:

[0131]

[0132] [Evaluation] The compositions produced in Examples 1 to 13 and Comparative Examples 1 to 7 were subjected to various evaluations.

[0133] (Amount of etching of polysilicon (Poly-Si) film) Thermal oxide film (SiO ２ ) having a silicon substrate (SiO ２ A polysilicon film (thickness: 600 Å) was formed on the silicon substrate (thickness: 1000 Å) by low pressure plasma CVD.

[0134] 1 cm x 1 cm (immersion treatment area: 1 cm ２The polysilicon film-formed sample was immersed in 10 mL of 1% hydrofluoric acid (DHF) at 23° C. for 5 minutes to remove the oxide film from the surface of the polysilicon film. The film thickness of the polysilicon film-formed sample before immersion in 1% hydrofluoric acid (DHF) was measured using a spectroscopic ellipsometer UVISEL Plus (manufactured by HORIBA, Ltd.).

[0135] Polysilicon film samples were immersed in 10 g of the compositions produced in Examples 1 to 13 and Comparative Examples 1 to 7 at 60° C. for 30 seconds. The film thickness of the polysilicon film sample after the immersion treatment was measured in the same manner as above.

[0136] The etching amount of the polysilicon film per 30 seconds was calculated by calculating the difference in film thickness between the polysilicon film sample before immersion in 1% hydrofluoric acid (DHF) and the polysilicon film sample after treatment with the composition. The results are shown in Table 2 below.

[0137] (Amount of etching of silicon oxide (th-Ox) film) A silicon oxide film was formed to a thickness of 1000 Å by thermal oxidation of a silicon wafer, and the film was etched to a thickness of 1 cm x 1 cm (immersion treatment area: 1 cm ２ ) to prepare silicon oxide film samples.

[0138] The film thickness of the silicon oxide film sample was measured using a spectroscopic ellipsometer UVISEL Plus (manufactured by Horiba, Ltd.).

[0139] The silicon oxide film-formed samples were immersed in 10 g of the compositions produced in Examples 1 to 13 and Comparative Examples 1 to 7 for 120 minutes at 60° C. The film thickness of the silicon oxide film-formed samples after the immersion treatment was measured in the same manner as above.

[0140] The amount of silicon oxide (th-Ox) film etched per 120 minutes was determined by calculating the difference in film thickness between before and after the treatment. The results are shown in Table 2 below.

[0141] (Polysilicon / Silicon Oxide Etching Selectivity) The etching rates of polysilicon and silicon oxide were calculated by dividing the etching amounts of the polysilicon (Poly-Si) film and the silicon oxide (th-Ox) film for the compositions produced in Examples 1 to 13 and Comparative Examples 1 to 7 by the immersion time. Next, the etching rate of polysilicon was divided by the etching rate of silicon oxide to calculate the etching selectivity of polysilicon (Poly-Si) / silicon oxide (th-Ox). The units for the etching rates of the polysilicon film and the silicon oxide (th-Ox) film were unified to "Å / min" for the calculations. The results obtained are shown in Table 2 below.

[0142]

[0143] The results in Table 2 show that the compositions of Examples 1 to 13 selectively etched polysilicon.

[0144] REFERENCE SIGNS LIST 10 Semiconductor substrate (before etching) 11 Silicon substrate 12 Sacrificial insulating film (silicon oxide region) 13 Sacrificial gate electrode (silicon region) 14 Insulating sidewall 15 Element isolation film 16 Extension region 17 Source / drain 18 Silicide region 19 Insulating film

Claims

1. a quaternary ammonium compound; at least one cationic surfactant selected from the group consisting of aryl group-containing cationic surfactants and heteroaryl group-containing cationic surfactants; A composition comprising:

2. The aryl group-containing cationic surfactant is represented by the following formula (1): 【Chemistry 1】 [In the formula, R １ is a substituted or unsubstituted alkyl group having 10 to 30 carbon atoms, R ２ are each independently a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, A is a single bond or a substituted or unsubstituted alkylene having 1 to 6 carbon atoms; Ar is a substituted or unsubstituted aryl group having 6 to 30 carbon atoms; X － is a halide, hydroxide, sulfate, hydrogen sulfate, sulfite, thiosulfate, nitrate, phosphate, monohydrogen phosphate, dihydrogen phosphate, carbonate, bicarbonate, or carboxylate. The composition of claim 1 ,

3. R １ The composition according to claim 2, wherein is a substituted or unsubstituted alkyl group having 10 to 15 carbon atoms.

4. The heteroaryl group-containing cationic surfactant is represented by the following formula (2) or (3): 【Chemistry 2】 [In the formula, R ３ is a substituted or unsubstituted alkyl group having 10 to 30 carbon atoms, R ４ is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, R ５ are each independently a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, X － is a halide, hydroxide, sulfate, hydrogen sulfate, sulfite, thiosulfate, nitrate, phosphate, monohydrogen phosphate, dihydrogen phosphate, carbonate, bicarbonate, or carboxylate. The composition of claim 1 ,

5. R ３ The composition according to claim 4, wherein is a substituted or unsubstituted alkyl group having 14 to 20 carbon atoms.

6. The composition of claim 1 further comprising an organic solvent.

7. 7. The composition of claim 6, wherein the organic solvent comprises at least one selected from the group consisting of alkanolamines, aprotic polar solvents, monoalcohols, and polyhydric alcohols.

8. The composition of claim 1 , wherein the quaternary ammonium compound comprises tetramethylammonium hydroxide (TMAH).

9. A method for producing a semiconductor substrate, comprising a silicon etching step of contacting a semiconductor substrate including a silicon region containing silicon and a silicon oxide region containing silicon oxide with the composition according to any one of claims 1 to 8.

10. A method for etching a semiconductor substrate, comprising a silicon etching step of contacting a semiconductor substrate including a silicon region containing silicon and a silicon oxide region containing silicon oxide with the composition according to any one of claims 1 to 8.

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