Etching liquid, etching method, and method for manufacturing semiconductor device

Abstract

This etching liquid contains an alkaline compound (A) and at least one compound (B) selected from the group consisting of thiol compounds (B1) and nonionic surfactants (B2) represented by formula (1), and satisfies ER110 / ER100≥0.5. Said ER110 represents the etching rate for the 110 plane of silicon crystals and said ER100 represents the etching rate for the 100 plane of silicon crystals.　(1): R1XO-(CmH2mO)n-R2. In the formula, R1 represents an alkyl group having 7 or more carbon atoms, R2 represents a hydrogen atom or an alkyl group, X represents a single bond or a phenylene group, m represents an integer of 1-6, and n represents 4-25.　This etching method comprises etching a structural body including silicon by using the etching liquid. This method for manufacturing a semiconductor device comprises a step for etching a structural body including silicon by using the etching liquid.　The present invention provides an etching liquid having excellent selective solubility for the 110 plane of silicon crystals with respect to the 100 plane of silicon crystals. Further, it is possible to provide an etching method and a method for manufacturing a semiconductor device, in which the etching liquid is used.

Description

Etching solution, etching method, and semiconductor device manufacturing method

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

[0002] In accordance with Moore's Law, the miniaturization of integrated circuits is progressing. In recent years, in addition to reducing the size of conventional planar transistors, studies have been conducted to further miniaturize and integrate transistors by changing the structure from planar to three-dimensional, such as fin transistors (fin field effect transistors) and gate-all-around transistors (GAA field effect transistors). As a transistor structure that is expected to enable further miniaturization, vertical field effect transistors (VFETs) are being studied, which change the structure from conventional planar transistors to vertical, allowing for further miniaturization and improved performance.

[0003] In a GAA FET, a nanosheet or nanowire channel is covered with a gate electrode, increasing the contact area between the channel and the gate electrode, thereby improving the transistor performance per unit area.

[0004] VFETs have a structure in which nanosheet or nanowire-like channels are stacked vertically, and the area of ​​the standard cell layout is smaller than that of planar transistors (HFETs), thereby improving the transistor performance per unit area.

[0005] To form a GAA FET or a VFET, an etching solution that dissolves silicon is required in the etching process. For example, Patent Documents 1 and 2 disclose etching solutions that contain alkaline compounds as etching solutions that dissolve silicon.

[0006] JP 2017-108122 A JP 2021-136429 A

[0007] However, the etching solutions disclosed in Patent Documents 1 and 2 are inferior in selective dissolution of the 110 plane of silicon crystal relative to the 100 plane of silicon crystal.

[0008] In particular, in recent years, there has been a strong demand for miniaturization of FETs, and it is necessary to control etching of silicon according to its plane orientation in narrow gaps of a few tens of nanometers. FETs, which are structured perpendicular to the 100 plane of silicon crystals, require etching from the horizontal direction to form nano-shapes, so an etching solution with excellent selective solubility for the 110 plane of silicon crystals is required. In particular, selective solubility according to plane orientation is not easy to control because the surface is composed of the same elements.

[0009] The present invention has been made in view of these problems, and an object of the present invention is to provide an etching solution that exhibits excellent selective dissolution of the 110 plane of a silicon crystal relative to the 100 plane of a silicon crystal. Another object of the present invention is to provide an etching method, a method for manufacturing a semiconductor device, a method for manufacturing a vertical transistor, and a method for manufacturing a gate-all-around transistor using the etching solution. Conventionally, methods for manufacturing color filters used in liquid crystal displays and the like have been known, including pigment dispersion methods, dyeing methods, electrodeposition methods, and printing methods. Among these, the pigment dispersion method, which has excellent average properties in terms of spectral characteristics, durability, pattern shape, accuracy, and the like, is the most widely adopted.

[0010] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an etching solution that has excellent selective dissolution of the 110 plane of a silicon crystal relative to the 100 plane of a silicon crystal. Another object of the present invention is to provide an etching method using the etching solution, a method for manufacturing a semiconductor device, a method for manufacturing a vertical transistor, and a method for manufacturing a gate-all-around transistor.

[0011] [1] An ER coating composition comprising an alkaline compound (A), and at least one compound (B) selected from the group consisting of a thiol compound (B1) and a nonionic surfactant (B2) represented by the following formula (1), １１０ / ER １００ The etching solution has an ER of ≥ 0.5. １１０ is the etching rate for the 110 plane of the silicon crystal, and the ER １００is the etching rate for the 100 plane of the silicon crystal. １ XO-(C ｍ H ２ｍ O) ｎ -R ２ (1) In the formula, R １ is an alkyl group having 7 or more carbon atoms, and R ２represents a hydrogen atom or an alkyl group, X represents a single bond or a phenylene group, m represents an integer of 1 to 6, and n represents a number of 4 to 25. [2] The etching solution according to [1], wherein the alkaline compound (A) contains at least one compound selected from the group consisting of a quaternary ammonium hydroxide compound, potassium hydroxide, and calcium hydroxide. [3] The etching solution according to [1] or [2], wherein the thiol compound (B1) contains a compound having a hydrocarbon group and a thiol group. [4] The etching solution according to any one of [1] to [3], wherein the thiol compound (B1) comprises at least one compound selected from the group consisting of thioglycerol, thioglycolic acid, ethanolamine thioglycolate, 8-mercaptooctanoic acid, 1-octanethiol, 1-undecanethiol, 1-dodecanethiol, 11-mercapto-1-undecanol, 11-mercaptoundecanoic acid, 16-mercaptohexadecanoic acid, 4,4'-dithiodibutyric acid, bis(2-hydroxyethyl)disulfide, and didodecanedisulfide. [5] The etching solution according to any one of [1] to [4], wherein X in formula (1) is a phenylene group. [6] The etching solution according to any one of [1] to [5], further comprising water. [7] The etching solution according to [6], wherein the content of water in 100% by mass of the etching solution is 60% by mass or more. [8] The etching solution according to any one of [1] to [7], wherein the content of the compound (B) in 100% by mass of the etching solution is 0.1% by mass to 39.99% by mass. [9] The etching solution according to any one of [1] to [8], wherein the content of the compound (B) in 100% by mass of the etching solution is 0.01% by mass to 5% by mass.

[10] The etching solution according to any one of [1] to [9], wherein the ratio of the mass of the thiol compound (B1) to the mass of the alkaline compound (A) is 0.001 to 2.

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

[10] , wherein the etching solution is used as an etching solution for dissolving silicon.

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

[11] , wherein the 110th plane of a silicon crystal is dissolved relative to the 100th plane of a silicon crystal.

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

[12] , wherein the silicon is single crystal silicon.

[14] An etching method for etching a silicon-containing structure using the etching solution according to any one of [1] to

[13] .

[15] A method for manufacturing a semiconductor device, comprising the step of etching a silicon-containing structure using the etching solution according to any one of [1] to

[13] .

[16] A method for manufacturing a vertical transistor, comprising the step of etching a silicon-containing structure using the etching solution according to any one of [1] to

[13] .

[17] A method for manufacturing a gate-all-around transistor, comprising the step of etching a silicon-containing structure using the etching solution according to any one of [1] to

[13] .

[18] A method for etching a silicon-containing structure, comprising the step of selectively etching the 110 plane of a silicon crystal relative to the 100 plane of the silicon crystal using an etching solution containing an alkaline compound (A) and at least one compound (B) selected from the group consisting of a thiol compound (B1) and a nonionic surfactant (B2) represented by the following formula (2): R. １ XO-(C ｍ H ２ｍ O) ｎ -R ２ (2) In the formula, R １ is an alkyl group having one or more carbon atoms, and R ２ is a hydrogen atom or an alkyl group, X is a single bond or a phenylene group, m is an integer of 1 to 6, and n is 4 to 25.

[19] A method for manufacturing a semiconductor device, comprising a step of selectively etching the 110 plane of a silicon crystal relative to the 100 plane of the silicon crystal using an etching solution containing an alkaline compound (A) and at least one compound (B) selected from the group consisting of a thiol compound (B1) and a nonionic surfactant (B2) represented by the following formula (2): R １ XO-(C ｍ H ２ｍ O) ｎ -R ２ (2) In the formula, R １ is an alkyl group having one or more carbon atoms, and R ２represents a hydrogen atom or an alkyl group; X represents a single bond or a phenylene group; m represents an integer of 1 to 6; and n represents an integer of 4 to 25.

[0012] The etching solution of the present invention has excellent selective solubility in the 110 plane of a silicon crystal relative to the 100 plane of a silicon crystal. The etching method of the present invention, the semiconductor device manufacturing method of the present invention, the vertical transistor manufacturing method of the present invention, and the gate-all-around transistor manufacturing method of the present invention have excellent selective solubility in the 110 plane of a silicon crystal relative to the 100 plane of a silicon crystal in the etching step, and therefore can perform highly accurate etching and produce desired products with a high yield.

[0013] The present invention will be described in detail below, but the present invention is not limited to the following embodiments and can be practiced with various modifications within the scope of the gist. In this specification, when the expression "to" is used, it is used as an expression including the numerical values ​​or physical property values ​​before and after it.

[0014] The etching solution of the present invention contains an alkaline compound (A) (hereinafter sometimes referred to as "component (A)"), and at least one compound (B) (hereinafter sometimes referred to as "component (B)") selected from the group consisting of a thiol compound (B1) (hereinafter sometimes referred to as "component (B1)") and a nonionic surfactant (B2) (hereinafter sometimes referred to as "component (B2)") represented by the following formula (1), and thereby has excellent selective solubility of the 110 face of a silicon crystal relative to the 100 face of a silicon crystal. The etching solution of the present invention preferably further contains water (hereinafter sometimes referred to as "component (C)"). R １ XO-(C ｍ H ２ｍ O) ｎ -R ２ (1) In the formula, R １ is an alkyl group having 7 or more carbon atoms, and R ２is a hydrogen atom or an alkyl group, X is a single bond or a phenylene group, m is an integer of 1 to 6, and n is 4 to 25. The reason why the etching solution of the present invention has excellent selective solubility for the 110 plane of a silicon crystal relative to the 100 plane of a silicon crystal is thought to be as follows. When silicon crystal is etched using the etching solution of the present invention, component (A) dissolves the silicon, and component (B) adsorbs and protects Siδ+ on the surface of the silicon crystal via covalent bonds. Component (B) more easily adsorbs and protects the surface of the silicon crystal for the 100 plane than for the 110 plane. As a result, it is thought that the etching solution of the present invention has excellent selective solubility for the 110 plane of a silicon crystal relative to the 100 plane of a silicon crystal.

[0015] (Component (A)) The component (A) is an alkaline compound (A). When the etching liquid of the present invention contains the alkaline compound (A), it has excellent silicon solubility.

[0016] Examples of component (A) include organic alkali compounds such as quaternary ammonium hydroxide compounds, such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, and tetrabutylammonium hydroxide; and inorganic alkali compounds such as metal hydroxides, such as sodium hydroxide, potassium hydroxide, and calcium hydroxide. These components (A) may be used alone or in combination of two or more. Among these components (A), quaternary ammonium hydroxide compounds, potassium hydroxide, and calcium hydroxide are preferred because they have a low content of sodium, which is likely to affect transistor performance; quaternary ammonium hydroxide compounds are more preferred, and tetramethylammonium hydroxide and tetrabutylammonium hydroxide are even more preferred.

[0017] The content of component (A) is preferably 0.1 mass% or more, more preferably 0.2 mass% or more, and even more preferably 0.5 mass% or more, based on 100 mass% of the etching solution, because of its excellent solubility in silicon. The content of component (A) is preferably 39.99 mass% or less, more preferably 34.95 mass% or less, and even more preferably 29.92 mass% or less, based on 100 mass% of the etching solution, because of its excellent solubility in water.

[0018] (Component (B)) Component (B) is at least one compound (B) selected from the group consisting of a thiol compound (B1) and a nonionic surfactant (B2). When the etching solution of the present invention contains component (B), it exhibits excellent selective adsorption of the 100-facet of silicon crystal.

[0019] (Component (B1)) Component (B1) is a thiol compound (B1). The thiol compound (B1) in the present invention may be one that decomposes in the etching solution to generate a thiol compound, and therefore, a compound that decomposes in the etching solution to generate a thiol compound, such as a disulfide compound, also falls under the category of component (B1) according to the present invention. In other words, the etching solution of the present invention may contain a disulfide compound as component (B1).

[0020] Component (B1) is preferably a compound having a hydrocarbon group and a thiol group, and more preferably a hydrophobic compound having a hydrocarbon group and a thiol group, because this has excellent adsorption stability on the silicon crystal surface.

[0021] Examples of component (B1) include thioglycerol, thioglycolic acid, ethanolamine thioglycolate, 8-mercaptooctanoic acid, 1-octanethiol, 1-undecanethiol, 1-dodecanethiol, 11-mercapto-1-undecanol, 11-mercaptoundecanoic acid, 16-mercaptohexadecanoic acid, 4,4'-dithiodibutyric acid, bis(2-hydroxyethyl)disulfide, didodecanedisulfide, etc. These components (B1) may be used alone or in combination of two or more. Among these components (B1), thioglycerol, thioglycolic acid, ethanolamine thioglycolate, 1-octanethiol, 1-undecanethiol, 1-dodecanethiol, 11-mercapto-1-undecanol, 11-mercaptoundecanoic acid, and 16-mercaptohexadecanoic acid are preferred, as they have excellent solubility in water; thioglycerol, thioglycolic acid, ethanolamine thioglycolate, 11-mercaptoundecanoic acid, and 16-mercaptohexadecanoic acid are more preferred, and 11-mercaptoundecanoic acid and 16-mercaptohexadecanoic acid are even more preferred.

[0022] (Component (B2)) Component (B2) is a nonionic surfactant (B) represented by the following formula (1): R １ XO-(C ｍ H ２ｍ O) ｎ -R ２ (1) In the formula, R １ is an alkyl group having 7 or more carbon atoms, and R ２ represents a hydrogen atom or an alkyl group; X represents a single bond or a phenylene group; m represents an integer of 1 to 6; and n represents an integer of 4 to 25.

[0023] R １ is an alkyl group having 7 or more carbon atoms, and is preferably an alkyl group having 7 to 12 carbon atoms because it has excellent hydrophobic adsorption to the silicon surface at the hydrogen terminal. ２is a hydrogen atom or an alkyl group, preferably a hydrogen atom or a methyl group, with a hydrogen atom being more preferred, as these provide excellent solubility in water. X is a single bond or a phenylene group, preferably a phenylene group, as these provide excellent adsorption stability on silicon surfaces. m is an integer of 1 to 6, preferably 1 to 3, as these provide excellent solubility in water. n is an integer of 4 to 25, preferably 8 to 25, as these provide excellent solubility in water and excellent adsorption stability on silicon surfaces.

[0024] Examples of component (B2) include octylphenol ethoxylate, polyethylene glycol mono-4-nonylphenyl ether, and polyoxyethylene lauryl ether. These components (B2) may be used alone or in combination of two or more. Among these components (B2), octylphenol ethoxylate, polyethylene glycol mono-4-nonylphenyl ether, and polyoxyethylene lauryl ether are preferred because of their excellent hydrophobic adsorption to the silicon surface at the hydrogen terminal, with octylphenol ethoxylate and polyethylene glycol mono-4-nonylphenyl ether being more preferred, and octylphenol ethoxylate being even more preferred.

[0025] The content of component (B) is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.08% by mass or more, based on 100% by mass of the etching solution, because it has excellent selective adsorption of the 100-plane of silicon crystals. The content of component (B) is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 2% by mass or less, based on 100% by mass of the etching solution, because it has excellent solubility in water. On the other hand, when component (B2) is used, the content may be 0.0001% by mass or more, or 0.0002% by mass or more, or 0.0003% by mass or more, based on 100% by mass of the etching solution, because it has excellent selective adsorption of the 100-plane of silicon crystals. Furthermore, when component (B2) is used, the content may be 0.001% by mass or less, or 0.0009% by mass or less, or 0.0008% by mass or less, based on 100% by mass of the etching solution, from the viewpoint of preventing foaming.

[0026] (Component (C)) The etching solution of the present invention preferably contains water (component (C)) in addition to the components (A) and (B).

[0027] The content of component (C) is preferably 60% by mass or more, more preferably 65% ​​by mass or more, and even more preferably 70% by mass or more, based on 100% by mass of the etching solution, because the etching solution is easy to produce and the solubility of components (A) and (B) is excellent. The content of component (C) is preferably 99.5% by mass or less, more preferably 98% by mass or less, and even more preferably 95% by mass or less, based on 100% by mass of the etching solution, because the solubility of silicon is excellent.

[0028] (Other Components) The etching solution of the present invention may contain other components in addition to component (A), component (B), and component (C) as long as the effects of the present invention are not impaired. However, the etching solution may not contain any components other than component (A), component (B), and component (C). For example, the content of the other components may be 0.001% by mass or less in 100% by mass of the etching solution. In other cases, the etching solution may be substantially free of other components. An etching solution that is substantially free of other components means that the content of the other components in 100% by mass of the etching solution is 0% by mass to 0.00001% by mass. Examples of other components that may be contained include chelating agents, water-miscible solvents, oxidizing agents, cationic surfactants, and anionic surfactants.

[0029] The etching solution of the present invention contains a chelating agent, which exerts a chelating effect of adsorption to each crystal face of silicon.

[0030] Examples of chelating agents include amine compounds, amino acids, and organic acids. These chelating agents may be used alone or in combination of two or more. Among these chelating agents, amine compounds, amino acids, and organic acids are preferred because of their excellent chelating effect, and amine compounds are more preferred.

[0031] Examples of the amine compound include ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraaminehexaacetic acid, diethylenetriaminepentakis(methylphosphonic acid), ethylenediamine-N,N'-bis[2-(2-hydroxyphenyl)acetic acid], N,N'-bis(3-aminopropane)ethylenediamine, N-methyl-1,3-diaminopropane, 2-aminoethanol, N-methyldiethanolamine, 2-amino-2-methyl-1-propanol, etc. These amine compounds may be used alone or in combination of two or more. Among these amine compounds, ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraaminehexaacetic acid, diethylenetriaminepentakis(methylphosphonic acid), ethylenediamine-N,N'-bis[2-(2-hydroxyphenyl)acetic acid], N,N'-bis(3-aminopropane)ethylenediamine, N-methyl-1,3-diaminopropane, 2-aminoethanol, N-methyldiethanolamine, and 2-amino-2-methyl-1-propanol are preferred because of their excellent chelating effect, and ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraaminehexaacetic acid, diethylenetriaminepentakis(methylphosphonic acid), and ethylenediamine-N,N'-bis[2-(2-hydroxyphenyl)acetic acid] are more preferred.

[0032] Examples of amino acids include glycine, arginine, histidine, and (2-dihydroxyethyl)glycine. These amino acids may be used alone or in combination of two or more. Among these amino acids, glycine, arginine, histidine, and (2-dihydroxyethyl)glycine are preferred, and (2-dihydroxyethyl)glycine is more preferred, due to their excellent chelating effect.

[0033] Examples of organic acids include oxalic acid, citric acid, tartaric acid, malic acid, and 2-phosphonobutane-1,2,4-tricarboxylic acid. These organic acids may be used alone or in combination of two or more. Among these organic acids, oxalic acid, citric acid, tartaric acid, malic acid, and 2-phosphonobutane-1,2,4-tricarboxylic acid are preferred because of their excellent chelating effect, and citric acid and 2-phosphonobutane-1,2,4-tricarboxylic acid are more preferred.

[0034] When the etching solution of the present invention contains a chelating agent, the content of the chelating agent is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, and even more preferably 0.01% by mass or more, relative to 100% by mass of the etching solution, because the chelating effect is excellent. When the etching solution of the present invention contains a chelating agent, the content of the chelating agent is preferably 25% by mass or less, more preferably 10% by mass or less, and even more preferably 6% by mass or less, relative to 100% by mass of the etching solution, because the solubility in water is excellent.

[0035] The etching solution of the present invention contains a water-miscible solvent, which has the effect of making a hydrophobic substance that is not miscible with water miscible with water.

[0036] The water-miscible solvent may be any solvent that has excellent solubility in water, and may have a solubility parameter (SP value) of 7.0 (cal / cm ３ ) １／２ A solvent of 9.0 (cal / cm ３ ) １／２ The above solvents are more preferred.

[0037] Examples of water-miscible solvents include polar protic solvents such as isopropanol, ethylene glycol, propylene glycol, methanol, ethanol, propanol, butanol, glycerol, and 2-(2-aminoethoxyethanol); polar aprotic solvents such as acetone, dimethyl sulfoxide, N,N-dimethylformamide, N-methylpyrrolidone, and acetonitrile; and nonpolar solvents such as hexane, benzene, toluene, and diethyl ether. These water-miscible solvents may be used alone or in combination of two or more.

[0038] When the etching liquid of the present invention contains a water-miscible solvent, the content of the water-miscible solvent is preferably 5% by mass or less, more preferably 1% by mass or less, based on 100% by mass of the etching liquid, and most preferably does not contain a water-miscible solvent.

[0039] (Mass Ratio of Each Component) The mass ratio of component (B) to component (A) in the etching solution of the present invention (mass of component (B) / mass of component (A), hereinafter referred to as "(B) / (A)") is preferably 0.001 to 2, more preferably 0.003 to 2, even more preferably 0.005 to 1, and even more preferably 0.01 to 0.5, because this provides an excellent balance between the solubility of silicon and the selective adsorption of the (100) face of silicon crystal.

[0040] When the etching solution of the present invention contains component (C), the mass ratio of component (A) to component (C) (mass of component (A) / mass of component (C), hereinafter referred to as "(A) / (C)") is preferably 0.001 to 0.7, more preferably 0.003 to 0.6, and even more preferably 0.005 to 0.5, in view of excellent silicon solubility.

[0041] When the etching solution of the present invention contains component (C), the mass ratio of component (B) to component (C) (mass of component (B) / mass of component (C), hereinafter referred to as "(B) / (C)") is preferably 0.0001 to 0.08, more preferably 0.0005 to 0.03, and even more preferably 0.001 to 0.01, because this provides excellent selective adsorption of the 100 face of silicon crystal.

[0042] (Method for Producing Etching Solution) The method for producing the etching solution of the present invention is not particularly limited, and the etching solution can be produced by mixing component (A), component (B), and, if necessary, component (C), and other components. The order of mixing is not particularly limited, and all of the components may be mixed at once, or some of the components may be mixed in advance and then the remaining components may be mixed.

[0043] (Physical Properties of Etching Solution) The pH of the etching solution of the present invention is preferably 8 to 14, more preferably 9 to 14, and even more preferably 10 to 14, in view of excellent silicon solubility.

[0044] The oxygen concentration of the etching solution of the present invention is preferably 10 ppm by mass or less, more preferably 5 ppm by mass or less, and even more preferably 1 ppm by mass or less, in order to suppress complete oxidation of silicon.

[0045] Etching rate ER for the 110 plane of silicon crystal １１０ is preferably 1 nm / min or more, more preferably 1.5 nm / min or more, and even more preferably 2 nm / min or more, because this provides excellent efficiency in forming nano-shapes in the horizontal direction.

[0046] Etching rate ER for the 100 plane of silicon crystal １００ is preferably 50 nm / min or less, more preferably 30 nm / min or less, and even more preferably 10 nm / min or less, because this provides excellent efficiency in forming nano-shapes in the horizontal direction.

[0047] Etching rate ER for the 111 plane of silicon crystal １１１ is excellent in forming a flat facet of the 110 plane of the silicon crystal, so that the rate is preferably 0.5 nm / min or more, more preferably 1.0 nm / min or more, and even more preferably 1.5 nm / min or more.

[0048] Preferential solubility of the 110 face of silicon crystal relative to the 100 face of silicon crystal (ER １１０ / ER １００ ) is 0.5 or more, preferably 0.6 to 10, more preferably 0.7 to 7, and even more preferably 0.8 to 5, because the melt processability of the silicon crystal in the horizontal direction is excellent.

[0049] Preferential solubility of the 111 plane of silicon crystal relative to the 110 plane of silicon crystal (ER １１１ / ER １１０ ) is preferably 0.2 or more, more preferably 0.3 to 5, and even more preferably 0.4 to 3, since this results in excellent flatness of the (110) plane of the silicon crystal.

[0050] In this specification, the etching rate and selective solubility are measured by the method described in the examples below.

[0051] (Subject to be etched by etching solution) The etching solution of the present invention has excellent selective solubility for the 110 face of a silicon crystal relative to the 100 face of a silicon crystal, and is therefore suitable as an etching solution for dissolving silicon, and is particularly suitable as an etching solution for dissolving the 110 face of a silicon crystal relative to the 100 face of a silicon crystal.

[0052] The silicon to be etched is preferably single crystal silicon because it has a crystal plane orientation. Single crystal silicon can be produced by a known method, and may be produced by cutting out a single crystal ingot or by epitaxial growth.

[0053] (Etching Method) The etching method of the present invention is a method of etching a silicon-containing structure using the etching solution of the present invention.

[0054] In another embodiment, the etching method of the present invention is a method for etching a silicon-containing structure, and includes a step of selectively etching the 110 plane of a silicon crystal relative to the 100 plane of the silicon crystal using an etching solution containing an alkaline compound (A) and at least one compound (B) selected from the group consisting of a thiol compound (B1) and a nonionic surfactant (B2) represented by the following formula (2): １ XO-(C ｍ H ２ｍ O) ｎ -R ２ (2) In the formula, R １ is an alkyl group having one or more carbon atoms, and R ２ represents a hydrogen atom or an alkyl group; X represents a single bond or a phenylene group; m represents an integer of 1 to 6; and n represents an integer of 4 to 25.

[0055] The silicon in the silicon-containing structure has a crystal plane orientation, and is therefore preferably single-crystal silicon. Single-crystal silicon can be produced by a known method, and may be produced by cutting out a single-crystal ingot or by epitaxial growth.

[0056] The silicon-containing structure may also contain a material other than silicon, such as silicon germanium, silicon oxide, silicon nitride, or silicon carbonitride.

[0057] The etching method may be a known method, such as a batch method or a single wafer method.

[0058] The temperature during etching is preferably 15° C. or higher, more preferably 20° C. or higher, since this can improve the etching rate. The temperature during etching is preferably 100° C. or lower, more preferably 80° C. or lower, since this can suppress damage to the substrate and provide excellent etching stability. The temperature during etching corresponds to the temperature of the etching solution during etching.

[0059] (Uses) The etching solution of the present invention is suitable as an etching solution for dissolving silicon, because it has excellent selective solubility for the 110 plane of a silicon crystal relative to the 100 plane of a silicon crystal, and is particularly suitable as an etching solution for dissolving the 110 plane of a silicon crystal relative to the 100 plane of a silicon crystal. Therefore, the etching solution of the present invention is suitable for etching semiconductor devices having silicon-containing structures, and is more suitable for vertical transistors having silicon-containing structures and gate-all-around transistors having silicon-containing structures, and is particularly suitable for vertical transistors having silicon-containing structures.

[0060] (Method for Manufacturing a Semiconductor Device) The method for manufacturing a semiconductor device of the present invention includes the step of etching a silicon-containing structure using the etching solution of the present invention.

[0061] In another embodiment, the method for producing a semiconductor device of the present invention includes a step of selectively etching the 110 plane of a silicon crystal relative to the 100 plane of the silicon crystal using an etching solution containing an alkaline compound (A) and at least one compound (B) selected from the group consisting of a thiol compound (B1) and a nonionic surfactant (B2) represented by the following formula (2): １ XO-(C ｍH ２ｍ O) ｎ -R ２ (2) In the formula, R １ is an alkyl group having one or more carbon atoms, and R ２ represents a hydrogen atom or an alkyl group; X represents a single bond or a phenylene group; m represents an integer of 1 to 6; and n represents an integer of 4 to 25.

[0062] The present invention will be explained in more detail below using examples, but the present invention is not limited to the description of the following examples as long as it does not deviate from the gist of the invention.

[0063] (Raw Materials) The following were used as raw materials for producing the etching solutions in the Examples and Comparative Examples. Component (A-1): potassium hydroxide Component (A-2): tetramethylammonium hydroxide Component (B-1): 11-mercaptoundecanoic acid Component (B-2): Triton X-100 (trade name, manufactured by Merck Ltd., octylphenol ethoxylate) Component (B-3): polyethylene glycol mono-4-nonylphenyl ether (n = approximately 18) Component (B-4): diethylene glycol monobutyl ether

[0064] (Preferential solubility of the 110 plane of silicon crystal relative to the 100 plane of silicon crystal) A silicon substrate having silicon crystals with a plane orientation of the 110 plane and the 100 plane was immersed in a 0.5 mass % aqueous solution of hydrofluoric acid for 3 minutes, and then rinsed with ultrapure water. Thereafter, the back surface of the silicon substrate was masked, and the silicon substrate was immersed in the etching solution obtained in the Examples and Comparative Examples at 60°C for 10 to 60 minutes. The film thickness of the silicon substrate before and after immersion was measured with a spectral interference film thickness meter, and the selective solubility of the 110 plane of silicon crystal relative to the 100 plane of silicon crystal was calculated using the following formulas (1) to (3). ER １１０ [nm / min] = (film thickness of silicon substrate before immersion [nm] - film thickness of silicon substrate after immersion [nm]) ÷ (immersion time [min]) (1) ER １００ [nm / min] = (film thickness of silicon substrate before immersion [nm] - film thickness of silicon substrate after immersion [nm]) ÷ (immersion time [min]) (2) Selective solubility = ER １１０ [nm / min]÷ER１００ [nm / min] (3)

[0065] (Preferential solubility of the 111 plane of silicon crystal relative to the 110 plane of silicon crystal) A silicon substrate having silicon crystals with a plane orientation of 111 and 110 was immersed in a 0.5 mass % aqueous solution of hydrofluoric acid for 3 minutes, and then rinsed with ultrapure water. The back surface of the silicon substrate was then masked, and the silicon substrate was immersed in the etching solutions obtained in the Examples and Comparative Examples at 60°C for 10 to 60 minutes. The film thickness of the silicon substrate before and after immersion was measured with a spectral interference film thickness meter, and the selective solubility of the 111 plane of silicon crystal relative to the 110 plane of silicon crystal was calculated using the following equations (4) to (6). ER １１１ [nm / min] = (film thickness of silicon substrate before immersion [nm] - film thickness of silicon substrate after immersion [nm]) ÷ (immersion time [min]) (4) ER １１０ [nm / min] = (film thickness of silicon substrate before immersion [nm] - film thickness of silicon substrate after immersion [nm]) ÷ (immersion time [min]) (5) Selective solubility = ER １１１ [nm / min]÷ER １１０ [nm / min] (6)

[0066] [Example 1-1] The components were mixed so that, based on 100 mass %, the component (A-1) was 0.56 mass %, the component (B-1) was 0.10 mass %, and water was the remainder, and the components were bubbled with nitrogen gas for 5 minutes to obtain an etching solution. The evaluation results of the obtained etching solution are shown in Table 1.

[0067] Example 1-2 Etching solutions were obtained in the same manner as in Example 1-1, except that the types and contents of the components of the etching solution were changed as shown in Table 1. The evaluation results of the obtained etching solutions are shown in Table 1.

[0068] Comparative Example 1-1 Etching solutions were obtained in the same manner as in Example 1-1, except that the types and contents of the components of the etching solution were changed as shown in Table 1. The evaluation results of the obtained etching solutions are shown in Table 1.

[0069] Comparative Example 1-2 An etching solution was obtained in the same manner as in Example 1-1, except that the types and contents of the components of the etching solution were changed as shown in Table 1. The evaluation results of the obtained etching solution are shown in Table 1.

[0070]

[0071] [Example 2-1] An etching solution was obtained by mixing the components so that, based on 100 mass% of the etching solution, the component (A-1) was 0.56 mass%, the component (B-2) was 0.10 mass%, and water was the remainder. The evaluation results of the obtained etching solution are shown in Table 2.

[0072] An etching solution was obtained in the same manner as in Example 2-1, except that nitrogen gas was bubbled for 5 minutes after mixing the components. The evaluation results of the obtained etching solution are shown in Table 2.

[0073] Example 2-3 Etching solutions were obtained in the same manner as in Example 2-1, except that the types and contents of the components of the etching solution were changed as shown in Table 2. The evaluation results of the obtained etching solutions are shown in Table 2.

[0074] [Example 2-4] Etching solutions were obtained in the same manner as in Example 2-2, except that the types and contents of the components of the etching solution were changed as shown in Table 2. The evaluation results of the obtained etching solutions are shown in Table 2.

[0075] Example 2-5 Etching solutions were obtained in the same manner as in Example 2-1, except that the types and contents of the components of the etching solution were changed as shown in Table 2. The evaluation results of the obtained etching solutions are shown in Table 2.

[0076] [Example 2-6] Etching solutions were obtained in the same manner as in Example 2-2, except that the types and contents of the components of the etching solution were changed as shown in Table 2. The evaluation results of the obtained etching solutions are shown in Table 2.

[0077] Example 2-7 Etching solutions were obtained in the same manner as in Example 2-1, except that the types and contents of the components of the etching solution were changed as shown in Table 2. The evaluation results of the obtained etching solutions are shown in Table 2.

[0078] [Example 2-8] Etching solutions were obtained in the same manner as in Example 2-2, except that the types and contents of the components of the etching solution were changed as shown in Table 2. The evaluation results of the obtained etching solutions are shown in Table 2.

[0079] Comparative Example 2-1 Etching solutions were obtained in the same manner as in Example 1, except that the types and contents of the components of the etching solution were changed as shown in Table 2. The evaluation results of the obtained etching solutions are shown in Table 2.

[0080] Comparative Example 2-2 An etching solution was obtained in the same manner as in Example 2-2, except that the types and contents of the components of the etching solution were changed as shown in Table 2. The evaluation results of the obtained etching solution are shown in Table 2.

[0081]

[0082] As can be seen from Tables 1 and 2, the etching solutions obtained in the Examples were excellent in selective solubility of the 110 plane of the silicon crystal relative to the 100 plane of the silicon crystal, and also showed improved selective solubility of the 111 plane of the silicon crystal relative to the 110 plane of the silicon crystal. On the other hand, the etching solutions obtained in the Comparative Examples were inferior in selective solubility of the 110 plane of the silicon crystal relative to the 100 plane of the silicon crystal and in selective solubility of the 111 plane of the silicon crystal relative to the 110 plane of the silicon crystal.

[0083] The etching solution of the present invention is suitable as an etching solution for dissolving silicon, because it has excellent selective solubility for the 110 plane of a silicon crystal relative to the 100 plane of a silicon crystal, and is particularly suitable as an etching solution for dissolving the 110 plane of a silicon crystal relative to the 100 plane of a silicon crystal. Therefore, the etching solution of the present invention is suitable for etching semiconductor devices having silicon-containing structures, and is more suitable for vertical transistors having silicon-containing structures and gate-all-around transistors having silicon-containing structures, and is particularly suitable for vertical transistors having silicon-containing structures.

Claims

1. An ER coating composition comprising an alkaline compound (A), and at least one compound (B) selected from the group consisting of a thiol compound (B1) and a nonionic surfactant (B2) represented by the following formula (1), １１０ / ER １００ ≧0.

5. １１０ is the etching rate for the 110 plane of the silicon crystal, and the ER １００ is the etching rate for the 100 plane of the silicon crystal.) R １ XO-(C ｍ H ２ｍ O) ｎ -R ２ (1) (wherein, R １ is an alkyl group having 7 or more carbon atoms; R ２ is a hydrogen atom or an alkyl group, X is a single bond or a phenylene group, m is an integer of 1 to 6, and n is an integer of 4 to 25.

2. The etching solution according to claim 1, wherein the alkaline compound (A) comprises at least one compound selected from the group consisting of quaternary ammonium hydroxide compounds, potassium hydroxide and calcium hydroxide.

3. The etching solution according to claim 1, wherein the thiol compound (B1) comprises a compound having a hydrocarbon group and a thiol group.

4. The etching solution according to claim 1, wherein the thiol compound (B1) comprises at least one compound selected from the group consisting of thioglycerol, thioglycolic acid, ethanolamine thioglycolate, 8-mercaptooctanoic acid, 1-octanethiol, 1-undecanethiol, 1-dodecanethiol, 11-mercapto-1-undecanol, 11-mercaptoundecanoic acid, 16-mercaptohexadecanoic acid, 4,4'-dithiodibutyric acid, bis(2-hydroxyethyl)disulfide, and didodecanedisulfide.

5. The etching solution according to claim 1, wherein X in the formula (1) is a phenylene group.

6. The etching solution of claim 1, further comprising water.

7. The etching solution according to claim 6, wherein the water content in 100% by mass of the etching solution is 60% by mass or more.

8. The etching solution according to claim 1, wherein the content of the alkaline compound (A) in 100% by mass of the etching solution is 0.1% by mass to 39.99% by mass.

9. The etching solution according to claim 1, wherein the content of the compound (B) in 100% by mass of the etching solution is 0.01% by mass to 5% by mass.

10. The etching solution according to claim 1, wherein the ratio of the mass of said compound (B) to the mass of said alkaline compound (A) is 0.001 to 2.

11. The etching solution according to claim 1, which is used as an etching solution for dissolving silicon.

12. The etching solution according to claim 1, which dissolves the 110 faces of silicon crystals relative to the 100 faces of silicon crystals.

13. The etching solution of claim 1, wherein the silicon is single crystal silicon.

14. An etching method comprising etching a silicon-containing structure using the etching solution according to any one of claims 1 to 13.

15. A method for manufacturing a semiconductor device, comprising the step of etching a silicon-containing structure using the etching solution according to any one of claims 1 to 13.

16. A method for manufacturing a vertical transistor, comprising the step of etching a silicon-containing structure using the etching solution according to any one of claims 1 to 13.

17. A method for manufacturing a gate-all-around transistor, comprising the step of etching a silicon-containing structure with the etching solution according to any one of claims 1 to 13.

18. A method for etching a silicon-containing structure, comprising the step of selectively etching the 110 plane of a silicon crystal relative to the 100 plane of a silicon crystal using an etching solution containing an alkaline compound (A) and at least one compound (B) selected from the group consisting of a thiol compound (B1) and a nonionic surfactant (B2) represented by the following formula (2). １ XO-(C ｍ H ２ｍ O) ｎ -R ２ (2) (wherein, R １ is an alkyl group having one or more carbon atoms; R ２ is a hydrogen atom or an alkyl group, X is a single bond or a phenylene group, m is an integer of 1 to 6, and n is an integer of 4 to 25.

19. A method for manufacturing a semiconductor device, comprising the step of selectively etching the 110 plane of a silicon crystal relative to the 100 plane of the silicon crystal, using an etching solution containing an alkaline compound (A) and at least one compound (B) selected from the group consisting of a thiol compound (B1) and a nonionic surfactant (B2) represented by the following formula (2). １ XO-(C ｍ H ２ｍ O) ｎ -R ２ (2) (wherein, R １ is an alkyl group having one or more carbon atoms; R ２ is a hydrogen atom or an alkyl group, X is a single bond or a phenylene group, m is an integer of 1 to 6, and n is an integer of 4 to 25.

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