Substrate processing liquid, substrate processing method, and substrate processing apparatus

Abstract

The present invention provides a substrate processing liquid for etching silicon oxide on a substrate, the substrate processing liquid containing (a) hydrogen fluoride and (b) a monoalkylamine or a monoalkylamine salt. The amount of the hydrogen fluoride is 10 wt% or less, the amount of the monoalkylamine or monoalkylamine salt is 0.0001 wt% to 0.1 wt%, and the monoalkylamine or monoalkylamine salt has a linear alkyl group having 12 to 14 carbon atoms. The substrate processing liquid can efficiently form a narrow space by etching.

Description

Substrate processing solution, substrate processing method, and substrate processing apparatus

[0001] The present disclosure relates to a substrate processing liquid, a substrate processing method, and a substrate processing apparatus.

[0002] In the manufacturing process of electronic components, a substrate is etched with a substrate processing solution to form a desired pattern.

[0003] Japanese Patent Application Laid-Open No. 2021-48369

[0004] A. Okuyama, et al., Solid State Phenomena,(2014),Vol.219,pp115-118

[0005] As patterns become finer, etching may be required to form narrow spaces (for example, patterns in the nanoscale region).

[0006] However, when a conventional substrate processing liquid is used to form a narrow space, the etching rate tends to be low, making it difficult to form the narrow space efficiently.

[0007] The present disclosure aims to provide a substrate processing solution that can efficiently form a narrow space by etching.The present disclosure also aims to provide a substrate processing method that can efficiently form a narrow space by etching.The present disclosure also aims to provide a substrate processing apparatus that can efficiently form a narrow space by etching.

[0008] The present disclosure includes the following aspects: [Item 1] A substrate processing solution for etching silicon oxide on a substrate, the substrate processing solution comprising: (a) hydrogen fluoride, and (b) a monoalkylamine or a monoalkylamine salt, wherein the amount of hydrogen fluoride is 10% by weight or less, and the amount of the monoalkylamine or monoalkylamine salt is 0.0001 to 0.1% by weight, and the monoalkylamine or monoalkylamine salt has a linear alkyl group having 12 to 14 carbon atoms. [Item 2] The substrate processing solution according to Item 1, wherein the monoalkylamine is dodecylamine or tetradecylamine. [Item 3] The substrate processing solution according to Item 1, wherein the monoalkylamine salt is dodecylamine hydrochloride or dodecylamine acetate. [Item 4] The substrate processing solution according to Item 1, consisting of (a) hydrogen fluoride, (b) the monoalkylamine or monoalkylamine salt, and (c) water. [Item 5] The substrate processing solution according to item 1, wherein the amount of the hydrogen fluoride is 0.5 to 7 wt %, the amount of the monoalkylamine is 0.0001 to 0.03 wt %, and the amount of the monoalkylamine salt is 0.001 to 0.05 wt %. [Item 6] A substrate processing method comprising: bringing a substrate processing solution into contact with a portion to be removed provided on a substrate to etch at least a portion of the portion to be removed, and forming a narrow space on the substrate by etching at least a portion of the portion to be removed, wherein the substrate processing solution contains: (a) hydrogen fluoride, and (b) a monoalkylamine or a monoalkylamine salt, wherein the amount of the hydrogen fluoride is 10 wt % or less, the amount of the monoalkylamine or the monoalkylamine salt is 0.0001 to 0.1 wt %, and the monoalkylamine or the monoalkylamine salt has a linear alkyl group having 12 to 14 carbon atoms. [Item 7] The substrate processing method according to Item 6, wherein the narrow space formed by the etching is a recess having an opening, and the shortest distance of the opening is 50 nm or less. [Item 8] The substrate processing method according to Item 7, wherein the depth of the recess is 30 nm or more.[Item 9] The substrate processing method according to Item 6, wherein the substrate has a semiconductor layer laminated on the portion to be removed, and the substrate processing solution etches at least a part of the portion to be removed between the substrate and the semiconductor layer to form the narrow space between the substrate and the semiconductor layer. [Item 10] The substrate processing method according to Item 6, wherein the monoalkylamine is dodecylamine or tetradecylamine. [Item 11] The substrate processing method according to Item 6, wherein the monoalkylamine salt is dodecylamine hydrochloride or dodecylamine acetate. [Item 12] A substrate processing apparatus according to Item 12, comprising: a processing section that brings a substrate processing liquid into contact with a portion to be removed provided on the substrate to etch at least a portion of the portion to be removed and form a narrow space on the substrate, wherein the substrate processing liquid contains: (a) hydrogen fluoride, and (b) a monoalkylamine or a monoalkylamine salt, wherein the amount of the hydrogen fluoride is 10% by weight or less, the amount of the monoalkylamine or the monoalkylamine salt is 0.0001 to 0.1% by weight, and the monoalkylamine or the monoalkylamine salt has a linear alkyl group having 12 to 14 carbon atoms. [Item 13] The substrate processing apparatus according to Item 12, wherein the processing section comprises: a substrate holding section that holds the substrate in a horizontal position, and a processing liquid supply section that supplies the substrate processing liquid to an upper surface of the substrate held by the substrate holding section. [Item 14] The substrate processing apparatus according to Item 12, wherein the processing section includes: a processing tank that stores the substrate processing liquid; a holding section that collectively holds the plurality of substrates in an upright position; and a lifting mechanism that raises and lowers the holding section relative to the processing tank to immerse the plurality of substrates in the substrate processing liquid or lifts them out of the substrate processing liquid.

[0009] The substrate processing solution of the present disclosure can efficiently form a narrow space by etching. The substrate processing method of the present disclosure can efficiently form a narrow space by etching. The substrate processing apparatus of the present disclosure can efficiently form a narrow space by etching.

[0010] FIG. 1A is a diagram illustrating a state before an etching process in a substrate processing method according to an embodiment of the present disclosure. FIG. 1B is a diagram illustrating a state after an etching process in a substrate processing method according to an embodiment of the present disclosure. FIG. 1C is a diagram illustrating an example of a method for processing a substrate, from FIG. 1A to FIG. 1B. FIG. 2A is a diagram illustrating a state of a surface layer portion of a main surface of a substrate before an etching process in a substrate processing method according to an embodiment of the present disclosure. FIG. 2B is a diagram illustrating a state of a surface layer portion of a main surface of a substrate after an etching process in a substrate processing method according to an embodiment of the present disclosure. FIG. 3 is a diagram schematically illustrating a configuration of a substrate processing apparatus according to an embodiment of the present disclosure. FIG. 4 is a block diagram illustrating an electrical configuration of the substrate processing apparatus illustrated in FIG. 3. FIG. 5 is a process diagram illustrating a first processing example of a cleaning process performed by the substrate processing apparatus illustrated in FIG. 3. FIG. 6 is a diagram illustrating changes in substrate rotation speed in each process included in the processing example of FIG. 5. FIG. 7 is a process diagram illustrating a second processing example of a cleaning process performed by the substrate processing apparatus illustrated in FIG. 3. FIG. 8A is a diagram illustrating the second processing example of FIG. 7. FIG. 8B is a diagram illustrating a process performed subsequent to FIG. 8A. FIG. 8C is a diagram showing a process performed subsequent to FIG. 8B . FIG. 8D is a diagram showing a process performed subsequent to FIG. 8C . FIG. 8E is a diagram showing a process performed subsequent to FIG. 8D . FIG. 9A is a diagram showing an in-plane distribution of an etching rate in a processing liquid puddle step. FIG. 9B is a diagram showing an in-plane distribution of an etching rate in a puddle rinse step. FIG. 10 is a process diagram showing a third process example of a cleaning process performed by the substrate processing apparatus shown in FIG. 3 . FIG. 11 is a process diagram showing a fourth process example of a cleaning process performed by the substrate processing apparatus shown in FIG. 3 . FIG. 12A is a diagram showing a first modified example of the present invention. FIG. 12B is a diagram showing a second modified example of the present invention. FIG. 12C is a diagram showing a third modified example of the present invention. FIG. 13 is a diagram showing a fourth modified example of the present invention. FIG. 14 is a vertical cross-sectional view of the substrate processing apparatus 301 according to the first embodiment taken along a plane parallel to the substrate W1. FIG. 15 is a vertical cross-sectional view of the substrate processing apparatus 301 according to the first embodiment taken along line A-A in FIG. 14 . FIG. 16 is a diagram showing the operation of the substrate processing apparatus 301 according to the first embodiment. FIG. 17 is a diagram showing the operation of the substrate processing apparatus 301 according to the first embodiment.FIG. 18 is a diagram showing the operation of the substrate processing apparatus 301 according to the first embodiment. FIG. 19 is a diagram showing a processing liquid supply system 340b of a substrate processing apparatus according to the second embodiment. FIG. 20A is a diagram showing a state in which a cylinder collapses due to uneven water residue R occurring between cylindrical capacitors. FIG. 20B is a diagram showing a state in which a cylinder collapses due to uneven water residue R occurring between cylindrical capacitors. FIG. 21A is a diagram showing a state in which cylinder collapse is suppressed when uneven water residue R does not occur between cylindrical capacitors. FIG. 21B is a diagram showing a state in which cylinder collapse is suppressed when uneven water residue R does not occur between cylindrical capacitors.

[0011] The substrate processing solution, the substrate processing method, and the substrate processing apparatus of the present disclosure will be described in more detail below. Although the description will be made with reference to the drawings as needed, the various elements in the drawings are merely shown schematically and as examples to facilitate understanding of the contents of the present disclosure, and the appearance and / or dimensional ratios may differ from those of the actual objects.

[0012] The various numerical ranges mentioned in this specification are intended to include the lower and upper limits themselves. That is, for example, a numerical range of 1 to 10 can be interpreted as including the lower limit of "1" and the upper limit of "10."

[0013] <Substrate Processing Liquid> The substrate processing liquid of the present disclosure is a substrate processing liquid for etching silicon oxide on a substrate, the substrate processing liquid comprising: (a) hydrogen fluoride; and (b) a monoalkylamine or a monoalkylamine salt, wherein the amount of hydrogen fluoride is 10 wt % or less, and the amount of the monoalkylamine or monoalkylamine salt is 0.0001 to 0.1 wt %, and the monoalkylamine or monoalkylamine salt has a linear alkyl group having 12 to 14 carbon atoms. By including the above components, the substrate processing liquid of the present disclosure can efficiently form a narrow space by etching.

[0014] Etching can sometimes form narrow spaces. For example, narrow spaces can be formed by removing silicon oxide or the like provided on a substrate by etching. When etching in a nanoscale region due to the miniaturization of electronic components, the opening of the narrow space formed can be on the nano-order, such as 50 nm. When forming such narrow spaces on the nano-order by etching, the etching rate can be slow with conventional substrate processing solutions. Although a predetermined etching can be achieved by extending the processing time, the increased processing time reduces throughput. In addition, this can cause changes in the shape of structures other than the removed portion, which can result in a decrease in yield because the desired structure cannot be obtained.

[0015] As a result of extensive research, the inventors of the present application have newly discovered that, when forming a narrow space, the etching rate is less likely to decrease by using a substrate processing solution having the above-described configuration. The substrate processing solution having the above-described configuration is less likely to decrease in etching rate when forming a narrow space, and can efficiently form a narrow space.

[0016] In one embodiment, the substrate processing solution of the present disclosure comprises (a) hydrogen fluoride, (b) a monoalkylamine or a monoalkylamine salt, and (c) water. In other words, the substrate processing solution of the present disclosure may comprise hydrofluoric acid and a monoalkylamine or a monoalkylamine salt. In such an embodiment, the narrow spaces are more easily formed by etching.

[0017] The substrate processing solution of the present disclosure can be used to etch silicon oxide.

[0018] [Surface tension] The surface tension of the substrate processing solution of the present disclosure may be 35 mN / m or less. The surface tension of the substrate processing solution of the present disclosure may be 30 mN / m or less, 25 mN / m or less, 20 mN / m or less, 18 mN / m or less, or 15 mN / m or less, or 5 mN / m or more, 10 mN / m or more, 12 mN / m or more, 15 mN / m or more, or 17 mN / m or more. When the surface tension of the substrate processing solution is within the above range, narrow spaces can be more efficiently formed by etching.

[0019] [Hydrogen Fluoride] The substrate processing solution of the present disclosure contains hydrogen fluoride.

[0020] [Amount of Hydrogen Fluoride] The amount of hydrogen fluoride in the substrate processing solution is 10% by weight or less. The amount of hydrogen fluoride in the substrate processing solution may be 10% by weight or less, 9% by weight or less, 8% by weight or less, 7% by weight or less, 6% by weight or less, or 5% by weight or less, or may be 0.1% by weight or more, 0.5% by weight or more, 1% by weight or more, 2% by weight or more, 3% by weight or more, 4% by weight or more, or 5% by weight or more. In one embodiment, the amount of hydrogen fluoride in the substrate processing solution may be 0.5 to 7% by weight or less.

[0021] When the substrate processing solution of the present disclosure is an aqueous solution, the amount of hydrogen fluoride may be considered as the concentration of hydrofluoric acid.

[0022] [Monoalkylamine] The substrate processing solution of the present disclosure may contain a monoalkylamine having a linear alkyl group having 12 to 14 carbon atoms.

[0023] [Number of Carbon Atoms in Alkylamine] The alkylamine has a linear alkyl group having 12 to 14 carbon atoms. The alkylamine may have a linear alkyl group having 12 or more or 13 or more carbon atoms, or may have a linear alkyl group having 14 or less or 13 or less carbon atoms.

[0024] The alkylamine may be at least one selected from the group consisting of dodecylamine, tridecylamine, and tetradecylamine. From the viewpoint of more efficiently forming a narrow space by etching, dodecylamine or tetradecylamine is preferred.

[0025] [Amount of Alkylamine] The amount of alkylamine in the substrate processing solution is 0.0001 to 0.1 wt %. The amount of monoalkylamine in the substrate processing solution may be 0.0001 wt % or more, 0.0005 wt % or more, 0.001 wt % or more, 0.003 wt % or more, 0.005 wt % or more, 0.007 wt % or more, 0.010 wt % or more, 0.013 wt % or more, or 0.015 wt % or more, and may be 0.1 wt % or less, 0.05 wt % or less, 0.03 wt % or less, 0.02 wt % or less, 0.015 wt % or less, or 0.01 wt % or less. In one embodiment, the amount of monoalkylamine may be 0.0001 to 0.03 wt %.

[0026] [Alkylamine Salt] The substrate processing solution according to the present disclosure may contain an alkylamine salt having a linear alkyl group having 12 to 14 carbon atoms. The alkylamine salt may be a hydrochloride, acetate, nitrate, or phosphate, and may be a hydrochloride or acetate from the viewpoint of more efficiently forming a narrow space by etching.

[0027] [Number of Carbon Atoms in Alkylamine Salt] The alkylamine salt has a linear alkyl group having 12 to 14 carbon atoms. The alkylamine salt may have a linear alkyl group having 12 or more or 13 or more carbon atoms, or may have a linear alkyl group having 14 or less or 13 or less carbon atoms.

[0028] The alkylamine salt may be at least one selected from the group consisting of dodecylamine salt, tridecylamine salt, and tetradecylamine salt. From the viewpoint of more efficiently forming a narrow space by etching, dodecylamine salt or tetradecylamine salt may be preferable.

[0029] From the viewpoint of forming a narrow space more efficiently by etching, the alkylamine salt may be dodecylamine acetate or dodecylamine hydrochloride.

[0030] [Amount of Monoalkylamine Salt] The amount of the monoalkylamine salt in the substrate processing solution is 0.0001 to 0.1 wt %. The amount of the monoalkylamine salt in the substrate processing solution may be 0.0001 wt % or more, 0.0005 wt % or more, 0.001 wt % or more, 0.003 wt % or more, 0.005 wt % or more, 0.007 wt % or more, 0.010 wt % or more, 0.013 wt % or more, or 0.015 wt % or more, and may be 0.1 wt % or less, 0.05 wt % or less, 0.03 wt % or less, 0.02 wt % or less, 0.015 wt % or less, or 0.01 wt % or less. In one embodiment, the amount of the monoalkylamine salt may be 0.001 to 0.05 wt %.

[0031] [Liquid Medium] The substrate processing solution of the present disclosure may contain a liquid medium. The liquid medium may be water, an organic solvent, or a mixture of water and an organic solvent. The substrate processing solution of the present disclosure is preferably an aqueous solution.

[0032] Examples of the organic solvent may be an alcohol-based solvent, a glycol-based solvent having two or more hydroxy groups, etc. Examples of the alcohol-based solvent and the glycol-based solvent having two or more hydroxy groups may include methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butyl alcohol, tert-butyl alcohol, cyclohexanol, ethylene glycol, and propylene glycol.

[0033] [Amount of Liquid Medium] The amount of the liquid medium may be 1 part by weight or more, 3 parts by weight or more, 5 parts by weight or more, 10 parts by weight or more, 20 parts by weight or more, 30 parts by weight or more, 40 parts by weight or more, or 50 parts by weight or more, relative to 1 part by weight of hydrogen fluoride, and may be 1,000 parts by weight or less, 500 parts by weight or less, 200 parts by weight or less, 175 parts by weight or less, 150 parts by weight or less, 125 parts by weight or less, 100 parts by weight or less, 80 parts by weight or less, 60 parts by weight or less, 40 parts by weight or less, 20 parts by weight or less, or 10 parts by weight or less.

[0034] In one embodiment, the amount of the liquid medium may be such that the hydrogen fluoride contained in the substrate processing solution of the present disclosure has a predetermined concentration.

[0035] [Other Components] The substrate processing solution of the present disclosure may contain components other than the above-described components, such as ammonium salts, alkylammonium salts, acids, and surfactants.

[0036] The ammonium salt includes ammonium ion NH ４ ＋ The general formula (NH ４ ＋ ) ｎ X ｎ - Ammonium fluoride NH ４ F (cation: NH ４ ＋ , anion F － ) Ammonium chloride NH ４ Cl (cation: NH ４ ＋ , anion Cl － ) Ammonium iodide NH ４ I (cation: NH ４ ＋, anion I － ), ammonium sulfide ((NH ４ ) ２ SO ４ ), sulfides such as ammonium acetate (CH ３ COONH ４ ) and other acetates.

[0037] The alkylammonium salts include those represented by the general formula (NR ４ ＋ ) ｎ X ｎ quaternary ammonium salts represented by R ３ tertiary amines represented by N, R ２ Secondary amines represented by NH, RNH ２ (R is an alkyl or aryl group), for example, tetramethylammonium fluoride [(CH ３ ) ４ N]F tetraethylammonium fluoride [(CH ３ CH ２ ) ４ N]F tetrabutylammonium fluoride [(CH ３ CH ２ CH ２ CH ２ ) ４ N]F tetramethylammonium chloride [(CH ３ ) ４ N]Cl tetraethylammonium chloride [(CH ３ CH ２ ) ４ N]Cl tetrabutylammonium chloride [(CH ３ CH ２ CH ２ CH ２ ) ４ N]Cl tetramethylammonium iodide [(CH ３ ) ４ N]I tetraethylammonium iodide [(CH ３ CH ２ ) ４ N]I tetrabutylammonium iodide [(CH ３ CH ２ CH２ CH ２ ) ４ N]I 2 , hydrogen sulfates such as tetrabutylammonium hydrogen sulfate, acetates such as tetramethylammonium acetate, hydroxides such as tetraethylammonium hydroxide, perchlorates such as tetrabutylammonium perchlorate, and the like.

[0038] Examples of the acid include hydrochloric acid, sulfuric acid, nitric acid, acetic acid, phosphoric acid, hydrogen peroxide, and citric acid.

[0039] Examples of surfactants include anionic surfactants (such as sodium dodecyl sulfate), cationic surfactants (such as cetyltrimethylammonium chloride), and nonionic surfactants (such as polyoxyalkylene alkyl ether).

[0040] [Amount of Other Components] The amount of each of the other components or the total amount thereof may be, relative to 100 parts by weight of hydrogen fluoride, 0.1 parts by weight or more, 1 part by weight or more, 3 parts by weight or more, 5 parts by weight or more, 10 parts by weight or more, 15 parts by weight or more, 20 parts by weight or more, 50 parts by weight or more, 75 parts by weight or more, or 100 parts by weight or more, and may be 500 parts by weight or less, 300 parts by weight or less, 200 parts by weight or less, 100 parts by weight or less, 50 parts by weight or less, 40 parts by weight or less, 30 parts by weight or less, 20 parts by weight or less, 10 parts by weight or less, or 5 parts by weight or less.

[0041] <Substrate Processing Method> A substrate processing method according to the present disclosure includes bringing a substrate processing solution into contact with a portion to be removed provided on a substrate to etch at least a portion of the portion to be removed, and forming a narrow space on the substrate by etching at least a portion of the portion to be removed, wherein the substrate processing solution contains: (a) hydrogen fluoride; and (b) a monoalkylamine or a monoalkylamine salt, wherein the amount of hydrogen fluoride is 10% by weight or less, and the amount of the monoalkylamine or monoalkylamine salt is 0.0001 to 0.1% by weight, and the monoalkylamine or monoalkylamine salt has a linear alkyl group having 12 to 14 carbon atoms. Due to the above characteristics, the substrate processing method according to the present disclosure can efficiently form a narrow space by etching.

[0042] [Substrate Processing Solution] The substrate processing solution used in the substrate processing method of the present disclosure comprises: (a) hydrogen fluoride; and (b) a monoalkylamine or a monoalkylamine salt, wherein the amount of hydrogen fluoride is 10 wt % or less; the amount of the monoalkylamine or the monoalkylamine salt is 0.0001 to 0.1 wt %, and the monoalkylamine or the monoalkylamine salt has a linear alkyl group having 12 to 14 carbon atoms.

[0043] The substrate processing liquid used in the substrate processing method of the present disclosure may be the substrate processing liquid of the present disclosure.

[0044] [Substrate] The substrate is a substrate used in the fields of semiconductor devices, liquid crystal display devices, etc., and may be, for example, a silicon substrate.

[0045] [Removal target portion] The removal target portion is a portion that can be removed by the substrate processing solution of the present disclosure. For example, the removal target portion is a portion that reacts with the substrate processing solution of the present disclosure and is removed. Examples of the removal target portion include silicon oxide, silicon nitride, etc.

[0046] The portion to be removed is provided on a substrate. The portion to be removed can be provided, for example, by subjecting the surface of the substrate to an oxidation treatment, a nitriding treatment, or the like. The oxidation treatment may be thermal oxidation, plasma CVD, or the like. The nitriding treatment may be thermal CVD, in which a mixed gas of chlorosilane and ammonia is supplied onto a substrate heated to 700°C or higher to form a film, or plasma CVD, in which activated species obtained by exciting a mixed gas of silane and ammonia with plasma are supplied onto a substrate heated to 350°C or higher to form a film.

[0047] In one embodiment, the portion to be removed may be silicon oxide.

[0048] [Thickness of the portion to be removed] The thickness of the portion to be removed may be 0.1 nm or more, 0.5 nm or more, 1.0 nm or more, 2.0 nm or more, 3.0 nm or more, 5.0 nm or more, 7.0 nm or more, 10.0 nm or more, 15.0 nm or more, 20.0 nm or more, 25.0 nm or more, or 30.0 nm or more, or may be 100 nm or less, 80.0 nm or less, 60.0 nm or less, 50.0 nm or less, 45.0 nm or less, 40.0 nm or less, 35.0 nm or less, 30.0 nm or less, 25.0 nm or less, 20.0 nm or less, 15.0 nm or less, 10.0 nm or less, or 5.0 nm or less.

[0049] [Narrow Space] In the present disclosure, a narrow space is a location formed on a substrate by etching at least a portion of a portion to be removed on the substrate. A narrow space refers to a location with a narrow opening surrounded by opposing and close walls. The opposing walls may extend while maintaining a certain interval or distance between them. The appearance of the narrow space is not particularly limited, but may be elongated overall, or may be slit-like or pinhole-like.

[0050] [Aspects of Recesses] In one embodiment, the narrow spaces formed by etching are recesses having openings, and the shortest distance of the openings may be 50 nm or less.

[0051] [H. Shortest distance of opening] The shortest distance H of the opening of the recess may be 0.1 nm or more, 0.5 nm or more, 1.0 nm or more, 2.0 nm or more, 3.0 nm or more, 5.0 nm or more, 7.0 nm or more, 10.0 nm or more, 15.0 nm or more, 20.0 nm or more, 25.0 nm or more, or 30.0 nm or more, or may be 100 nm or less, 80.0 nm or less, 60.0 nm or less, 50.0 nm or less, 45.0 nm or less, 40.0 nm or less, 35.0 nm or less, 30.0 nm or less, 25.0 nm or less, 20.0 nm or less, 15.0 nm or less, 10.0 nm or less, or 5.0 nm or less.

[0052] [D. Depth of Recesses] The depth D of the recesses may be 30 nm or more, 50 nm or more, 100 nm or more, 150 nm or more, 200 nm or more, 250 nm or more, 300 nm or more, 400 nm or more, or 500 nm or more, or may be 1000 nm or less, 800 nm or less, 600 nm or less, or 500 nm or less. The depth of the recesses means the length from the opening of the recesses to the bottom of the recesses.

[0053] [Specific Example of Substrate Processing Method] A specific example of the substrate processing method of the present disclosure will be described below.

[0054] 1A and 1B show a substrate processing method according to one embodiment of the present disclosure. Fig. 1A shows a stack W. In Fig. 1A, a substrate W1, a portion W2 to be removed, and a semiconductor layer W3 are stacked in this order.

[0055] A semiconductor layer W3 is provided on a substrate W1 and stacked on a portion to be removed W2 (FIG. 1A), and the substrate processing solution etches at least a part of the portion to be removed W2 between the substrate W1 and the semiconductor layer W3 to form a narrow space W6 between the substrate W1 and the semiconductor layer W3 (FIG. 1B). The semiconductor layer W3 may be a polysilicon film.

[0056] In Fig. 1B, the narrow space W6 is a recess with an opening. The shortest distance of the opening is represented by H, and the depth of the narrow space is represented by D. In Fig. 1B, the direction of the shortest distance H of the opening is the stacking direction. In Fig. 1B, the direction of the depth of the narrow space is the extension direction of the main surface of the portion to be removed W2 or a direction perpendicular to the stacking direction.

[0057] 1C shows an example of processing from FIG. 1A to FIG. 1B by removing the portion to be removed W2 by etching. In the stacked structure W shown in FIG. 1C, the portion to be removed W2 is formed on the upper surface of the substrate W1. Furthermore, a semiconductor layer W3 is stacked on the portion to be removed W2. This semiconductor layer W3 has a plurality of through holes W4, each having an inner diameter of 60 nm, for example.

[0058] When diluted hydrofluoric acid (DHF) is supplied to the surface of the laminate W configured in this way, the diluted hydrofluoric acid is supplied to the removal target portion W2 through the through-holes W4, and the etchant (HF ２ - ) etches the exposed region W5 of the portion to be removed W2 facing the through-hole W4, and as time passes, the etchant (HF ２ - ) penetrates into the minute region W7 sandwiched between the substrate W1 and the semiconductor layer W3, thereby causing etching of the minute region W7 to proceed.

[0059] In FIG. 1C, W1 may correspond to the silicon substrate, W2 may correspond to the thermal oxide layer, and W3 may correspond to the polysilicon layer.

[0060] Conventionally, when the narrow space W6 is formed by etching the removal target portion W2 with a substrate processing liquid, the etching rate can decrease as the narrow space W6 becomes narrower (for example, as the opening of the narrow space W6 becomes smaller or the narrow space W6 becomes deeper). When a nanoscale narrow space is formed by etching, the etching rate can decrease significantly if the opening is 50 nm or less.

[0061] 1B , the portion to be removed W2 between the substrate W1 and the semiconductor layer W3 is removed to form a narrow space W6 whose opening has a shortest distance H. As shown in FIG. 1B , if the shortest distance H of the opening of the narrow space W6 is 50 nm or less, the etching rate may decrease significantly. Furthermore, if the narrow space W6 continues to be formed in the direction of the depth D (i.e., in the direction in which the depth D increases along the extending direction of the main surface of the substrate W1) while maintaining the shortest distance H, the efficiency of forming the narrow space may decrease significantly at the reduced etching rate.

[0062] In the substrate processing method of the present disclosure, when the substrate processing solution of the present disclosure is used to form a narrow space by etching, the etching rate is likely to be higher than in the past, and therefore the substrate processing method of the present disclosure can efficiently form a narrow space.

[0063] [Embodiment for Removing a Portion to be Removed in a Trench] In one embodiment, the substrate processing method of the present disclosure can be applied to a recessing process. The recessing process is a process for recessing the surface of an insulator layer or metal layer embedded in a trench toward the bottom of the trench, and requires etching the insulator layer or metal layer with high uniformity across the entire upper surface of the substrate. Note that the insulator layer or metal layer to be etched corresponds to the portion to be removed in the substrate processing method of the present disclosure.

[0064] The following describes the changes in the surface layer of the upper surface of the substrate during the recessing process.

[0065] 2A and 2B are schematic diagrams illustrating an example of changes in the surface layer 110 of the substrate W1 due to etching processing, with Fig. 2A showing the state of the surface layer 110 of the substrate W1 before etching processing, and Fig. 2B showing the state of the surface layer 110 of the substrate W1 after etching processing.

[0066] 2A, a surface layer 110 on the upper surface of the substrate W1 to be etched is formed with, for example, a semiconductor layer 112 having a plurality of trenches 111 formed therein, and a plurality of insulator layers 113 embedded in the plurality of trenches 111, respectively. The semiconductor layer 112 is, for example, a semiconductor layer made of polysilicon or the like. The insulator layer 113 is, for example, a silicon oxide (SiO ２ ) or titanium nitride (TiN). Silicon oxide is, for example, an element isolation layer for electrically isolating devices formed on the upper surface of the substrate W1 from one another.

[0067] The depth direction DD1 of the trench 111 is also the thickness direction TD of the substrate W1 (the direction normal to the main surface of the substrate W1). The trench 111 has a depth Dp1 of, for example, 10 nm or more and 10,000 nm or less. The trench 111 has a width w1 of 10 nm or more and 100 nm or less as viewed from the depth direction DD1 of the trench 111.

[0068] The trench 111 is, for example, linear. The width W1 of the linear trench 111 refers to the size of the trench 111 in the direction in which the trench 111 extends and in the direction perpendicular to the thickness direction TD of the substrate W1.

[0069] The trench 111 does not necessarily have to be linear, and may be circular in plan view (as viewed from the normal direction to the main surface of the substrate W1). When the trench 111 is circular, the width W1 corresponds to the diameter of the trench 111. The multiple trenches 111 may be completely separated by the semiconductor layer 112, or the insulator layers 113 in the trenches 111 may be connected to each other.

[0070] 2B, the etching process partially removes the insulator layer 113, and the surface of the insulator layer 113 retreats toward the bottom of the trench 111. When the recess process is an isolation layer recess process (STI oxide film recess process), the insulator layer 113 is silicon oxide.

[0071] <Substrate Processing Apparatus> A substrate processing apparatus according to the present disclosure includes a processing unit that brings a substrate processing solution into contact with a portion to be removed provided on a substrate, thereby etching at least a portion of the portion to be removed and forming a narrow space on the substrate, wherein the substrate processing solution includes: (a) hydrogen fluoride, and (b) a monoalkylamine or a monoalkylamine salt, wherein the amount of hydrogen fluoride is 10% by weight or less, and the amount of the monoalkylamine or monoalkylamine salt is 0.0001 to 0.1% by weight, and the monoalkylamine or monoalkylamine salt has a linear alkyl group having 12 to 14 carbon atoms. By including the above configuration, the substrate processing apparatus according to the present disclosure can efficiently form a narrow space by etching.

[0072] [Substrate Processing Liquid] The substrate processing liquid used in the substrate processing apparatus of the present disclosure contains: (a) hydrogen fluoride; and (b) a monoalkylamine or a monoalkylamine salt, wherein the amount of hydrogen fluoride is 10 wt % or less; the amount of the monoalkylamine or the monoalkylamine salt is 0.0001 to 0.1 wt %, and the monoalkylamine or the monoalkylamine salt has a linear alkyl group having 12 to 14 carbon atoms.

[0073] The substrate processing liquid used in the substrate processing apparatus of the present disclosure may be the substrate processing liquid of the present disclosure.

[0074] [Processing Section] In the processing section, a substrate processing solution is brought into contact with a portion to be removed provided on the substrate, and at least a part of the portion to be removed is etched to form a narrow space on the substrate. The narrow space is as described above.

[0075] The substrate processing apparatus of the present disclosure may be configured as a single wafer or batch type. Single wafer and batch type substrate processing apparatuses are described below.

[0076] <Single-Wafer Type Substrate Processing Apparatus> The single-wafer type refers to a method in which substrates are processed one by one.

[0077] In a single-wafer type embodiment, the processing section includes a substrate holding section that holds the substrate in a horizontal position, and a processing liquid supply section that supplies a substrate processing liquid to an upper surface of the substrate held by the substrate holding section.

[0078] 3 is a diagram schematically illustrating the configuration of a substrate processing apparatus 201 according to an embodiment of the present disclosure. The substrate processing apparatus 201 is a single-wafer processing apparatus for performing substrate processing (specifically, cleaning processing) on ​​the surface (surface to be processed) of a substrate W1 such as a semiconductor wafer.

[0079] The substrate processing apparatus 201 includes a processing chamber 202 partitioned by a partition wall (not shown), a substrate holding unit 203 that holds and rotates a substrate W1, and a processing liquid supply unit 204 that supplies a processing liquid to the surface (top surface) of the substrate W1 held by the substrate holding unit 203.

[0080] In addition to the above configuration, the substrate processing apparatus 201 further includes a rinse liquid supply unit 205 (the rinse liquid supply unit is also referred to as a rinse liquid supply means) for supplying DIW (deionized water) as an example of a rinse liquid to the upper surface of the substrate W1 held by the substrate holding unit 203, and an organic solvent supply unit 206 (the organic solvent supply unit is also referred to as an organic solvent supply means) for supplying isopropyl alcohol (IPA) liquid as an example of an organic solvent having low surface tension.

[0081] [203. Substrate Holding Unit] The substrate holding unit 203 may be, for example, a clamping type, such as a spin chuck. Specifically, the substrate holding unit 203 includes a spin motor 207 (the spin motor is also referred to as a substrate rotation unit), a spin shaft (not shown) integrated with the drive shaft of the spin motor 207, a disk-shaped spin base 208 attached substantially horizontally to the upper end of the spin shaft, and a plurality of clamping members 209 provided at substantially equiangular intervals at multiple locations on the periphery of the spin base 208. The clamping members 209 clamp the substrate W1 in a substantially horizontal position. When the spin motor 207 is driven in this state, the spin base 208 is rotated by its driving force about a predetermined rotation axis (vertical axis) A1, and together with the spin base 208, the substrate W1 is rotated about the rotation axis A1 while maintaining a substantially horizontal position.

[0082] The substrate holding unit 203 is not limited to a clamping type, and may be, for example, a vacuum suction type that holds the substrate W1 in a horizontal position by vacuum suctioning the back surface (lower surface) of the substrate W1, and then rotates the held substrate W1 around the rotation axis A1 in that state, thereby rotating the held substrate W1.

[0083] [204. Processing Liquid Supply Unit] The processing liquid supply unit 204 (processing liquid supply unit also referred to as processing liquid nozzle) is, for example, a straight nozzle that discharges the processing liquid in a continuous flow state, and is fixedly disposed above the substrate holding unit 203 with its discharge port facing the vicinity of the center of rotation of the upper surface of the substrate W1. A processing liquid supply pipe 213 through which the processing liquid is supplied from a processing liquid supply source is connected to the processing liquid supply unit 204. A processing liquid valve 214 (processing liquid valve also referred to as processing liquid supply means) for switching between supplying and stopping the supply of the processing liquid from the processing liquid supply unit 204 is interposed in the middle of the processing liquid supply pipe 213. Examples of the processing liquid include, in addition to the substrate processing liquid disclosed herein, dilute hydrofluoric acid (DHF), concentrated hydrofluoric acid (concHF), hydrofluoric nitric acid (hydrofluoric acid and nitric acid (HNO ３ ) or ammonium fluoride, etc., are used.

[0084] The processing liquid supply unit 204 is, for example, a straight nozzle that discharges the processing liquid in the form of a continuous flow, and has a basic form as a scan nozzle that can change the supply position of the processing liquid on the upper surface of the substrate W1.

[0085] The processing liquid supply unit 204 is supported at the tip of a first arm 240 that extends substantially horizontally above the substrate holding unit 203. The base end of the first arm 240 is fixed to the upper end of a first arm support shaft 241 that extends substantially vertically to the side of the substrate holding unit 203. A first arm swinging mechanism 242 consisting of a motor or the like is coupled to this first arm support shaft 241. By swinging the first arm 240 by the first arm swinging mechanism 242, the processing liquid supply unit 204 can be moved between above the center of rotation of the substrate W1 held by the substrate holding unit 203 (on the rotation axis A1) and a home position provided at a position to the side of the substrate holding unit 203.

[0086] [205. Rinse Liquid Supply Unit] The rinse liquid supply unit 205 (the rinse liquid supply unit is also referred to as a rinse liquid nozzle) is, for example, a straight nozzle that ejects DIW in a continuous flow state, and has a basic form as a scan nozzle that can change the supply position of DIW on the upper surface of the substrate W1.

[0087] The rinsing liquid supply unit 205 is supported at the tip of a second arm 210 that extends substantially horizontally above the substrate holding unit 203. The base end of the second arm 210 is fixed to the upper end of a second arm support shaft 211 that extends substantially vertically to the side of the substrate holding unit 203. A second arm swinging mechanism 212 consisting of a motor or the like is coupled to this second arm support shaft 211. By swinging the second arm 210 by the second arm swinging mechanism 212, the rinsing liquid supply unit 205 can be moved between above the center of rotation of the substrate W1 held by the substrate holding unit 203 (on the rotation axis A1) and a home position provided to the side of the substrate holding unit 203.

[0088] A rinse liquid supply pipe 215, through which DIW is supplied from a DIW supply source, is connected to the rinse liquid supply unit 205. A rinse liquid valve 216 (the rinse liquid valve is also referred to as a rinse liquid supply means) for switching between supplying and stopping the supply of DIW from the rinse liquid supply unit 205 is provided midway along the rinse liquid supply pipe 215.

[0089] [206. Organic Solvent Supply Unit] The organic solvent supply unit 206 (also referred to as an organic solvent nozzle) is, for example, a straight nozzle that discharges IPA liquid in the form of a continuous stream, and is fixedly disposed above the substrate holding unit 203 with its discharge port facing toward the vicinity of the center of rotation of the upper surface of the substrate W1. An organic solvent supply pipe 218, through which IPA liquid is supplied from an IPA liquid supply source, is connected to the organic solvent supply unit 206. An organic solvent valve 219 is provided midway through the organic solvent supply pipe 218 to switch between supplying and stopping the supply of IPA liquid from the organic solvent supply unit 206.

[0090] It should be noted that the organic solvent supply units 206 do not need to be fixedly positioned relative to the substrate holding unit 203, and may, for example, be attached to an arm that can swing in a horizontal plane above the substrate holding unit 203, and the swinging of this arm scans the landing position of the organic solvent on the upper surface of the substrate W1, in the form of a so-called scanning nozzle.

[0091] FIG. 4 is a block diagram showing the electrical configuration of the substrate processing apparatus 201. As shown in FIG.

[0092] [220. Control Device] The substrate processing apparatus 201 is equipped with a control device 220 (the control device is also referred to as a control means) configured to include a microcomputer. The control device 220 controls the operations of the spin motor 207, the first and second arm swing mechanisms 242, 212, etc. in accordance with a predetermined program. Furthermore, the control device 220 controls the opening and closing operations of the processing liquid valve 214, the rinse liquid valve 216, the organic solvent valve 219, etc.

[0093] [Processing Example] Hereinafter, a processing example using the substrate processing apparatus of the present disclosure will be described.

[0094] Fig. 5 is a process chart showing a first example of substrate processing performed by the substrate processing apparatus 201. Fig. 6 is a diagram showing changes in the rotation speed of the substrate W1 in each step included in the substrate processing.

[0095] A first processing example of substrate processing using the substrate processing apparatus of the present disclosure will be described with reference to FIGS.

[0096] (First Processing Example) As a first processing example of the substrate processing, oxide film etching for removing an oxide film formed on the surface of the substrate W1 (the surface on which a device is to be formed) will be described.

[0097] - Substrate Placement Process During substrate processing, a transfer robot (not shown) is controlled to load an unprocessed substrate W1 into the processing chamber 202 (see FIG. 3) (step S1). Examples of this substrate W1 include a silicon wafer having an oxide film formed on its surface, and the substrate W1 exemplified in the substrate processing method of the present disclosure. The substrate W1 may be a large substrate (e.g., a circular substrate with an outer diameter of 200 mm or 300 mm). The substrate W1 is transferred to the substrate holder 203 with its front surface facing upward. At this time, the processing liquid supply unit 204 and the rinse liquid supply unit 205 are each positioned in their home positions so as not to interfere with the loading of the substrate W1.

[0098] Etching Process Once the substrate W1 is held by the substrate holder 203, the control device 220 starts the treatment liquid coating process (step S2). Specifically, the control device 220 controls the spin motor 207 to start rotating the substrate W1 and increase the rotational speed of the substrate W1 to a relatively high rotation speed (e.g., 600 to 1200 rpm). Concurrently, the control device 220 controls the first arm swing mechanism 242 to move the treatment liquid supply unit 204 above the substrate W1 and position the treatment liquid supply unit 204 on the rotation center (rotation axis A1) of the substrate W1. Once the treatment liquid supply unit 204 is positioned on the rotation center of the substrate W1, the control device 220 opens the treatment liquid valve 214 to discharge the treatment liquid from the treatment liquid supply unit 204 toward the center of the upper surface of the substrate W1. The discharge flow rate of the treatment liquid from the treatment liquid supply unit 204 at this time is set to, for example, 2.0 (liters / minute). The processing liquid supplied from the processing liquid supply unit 204 to the center of the substrate W1 is spread by centrifugal force, and the entire surface of the substrate W1 is covered with a liquid film of the processing liquid. Then, processing with the processing liquid begins over the entire surface of the substrate W1.

[0099] After a predetermined time has elapsed and the entire surface of the substrate W1 is covered with a film of the processing liquid, the control device 220 initiates a processing liquid puddle process (step S3) in which a puddle-shaped film of the processing liquid is formed and maintained on the upper surface of the substrate W1. Specifically, the control device 220 controls the spin motor 207 to quickly decelerate the rotation speed of the substrate W1 to a rotation speed (e.g., about 10 rpm) lower than that during the processing liquid covering process (step S2). The discharge flow rate of the processing liquid from the processing liquid supply unit 204 is maintained at 2.0 (liters / minute). Due to the reduction in the rotation speed of the substrate W1, the processing liquid supplied from the processing liquid supply unit 204 is pooled on the surface of the substrate W1 without being splashed on the surface of the substrate W1, forming a puddle-shaped film of the processing liquid.

[0100] The rotation speed of the substrate W1 during the formation of the puddle-shaped liquid film is not limited to the above-mentioned values, and may be set to any rotation speed that allows the processing liquid to form a puddle-shaped mound, or the rotation speed of the substrate W1 may be set to zero, i.e., the substrate W1 may be stationary. That is, the rotation speed of the substrate W1 is set to a speed (puddle speed) at which the centrifugal force acting on the processing liquid film on the surface of the substrate W1 is smaller than the surface tension acting between the processing liquid and the surface of the substrate W1, or at which the centrifugal force and the surface tension are approximately equal to each other.

[0101] The entire upper surface of the substrate W1 is treated with the treatment liquid by this film of treatment liquid. Furthermore, because the rotation speed of the substrate W1 is maintained at the paddle speed, the treatment liquid discharged from the substrate W1 is suppressed or prevented from hitting peripheral components and bouncing back toward the substrate W1. When a predetermined treatment liquid treatment time has elapsed since the start of discharge of the treatment liquid, the control device 220 closes the treatment liquid valve 214 to stop the discharge of the treatment liquid from the treatment liquid supply unit 204, and controls the first arm swing mechanism 242 to return the treatment liquid supply unit 204 to its home position after the discharge of the treatment liquid has stopped. When an etching liquid such as dilute hydrofluoric acid, concentrated hydrofluoric acid, nitric acid hydrofluoric acid, or ammonium fluoride is used as the treatment liquid, the surface of the substrate W1 becomes hydrophobic after treatment with the treatment liquid.

[0102] - Rinse Step Next, the control device 220 starts a puddle rinse step (step S4) in which the processing liquid on the upper surface of the substrate W1 is replaced with a rinse liquid (DIW). At the time of starting the puddle rinse step (step S4), the control device 220 maintains the substrate rotation speed in the processing liquid puddle step (S3). The control device 220 also controls the second arm swing mechanism 212 to move the rinse liquid supply unit 205 above the substrate W1 and position the rinse liquid supply unit 205 on the center of rotation of the substrate W1.

[0103] When the rinse liquid supply unit 205 is positioned above the rotation center of the substrate W1, the control device 220 opens the rinse liquid valve 216 to discharge DIW from the rinse liquid supply unit 205 toward the center of the upper surface of the substrate W1. The discharge flow rate of DIW from the rinse liquid supply unit 205 at this time is set to, for example, 2.0 (liters / minute). Since the rotation speed of the substrate W1 is maintained at the paddle speed during the period from the processing liquid puddle step (step S3) to the puddle rinse step (step S4), the upper surface of the substrate W1 is kept entirely covered with a puddle-shaped liquid film of the processing liquid throughout that period, preventing the upper surface of the substrate W1 from being exposed.

[0104] When DIW is further supplied from the rinse liquid supply unit 205 toward the center of the liquid film, the liquid film of the processing liquid on the substrate W1 is gradually pushed outward from the center of the substrate W1, discharged from the peripheral edge of the substrate W1, and replaced with DIW. After a predetermined time has passed, the entire liquid film of the processing liquid on the substrate W1 is replaced by DIW, and a puddle-shaped liquid film of DIW is formed over the entire upper surface of the substrate W1. This liquid film of DIW washes away the processing liquid adhering to the entire upper surface of the substrate W1.

[0105] The substrate rotation speed in the paddle rinse step (step S4) is set to a paddle speed (e.g., 10 rpm). Because the centrifugal force acting on the processing liquid and DIW on the substrate W1 is small, the amount of processing liquid and DIW splashing out from the periphery of the substrate W1 is suppressed. Because the substrate W1 is rotated at the paddle speed, a paddle-shaped film of DIW is maintained on the top surface of the substrate W1 throughout the paddle rinse step (step S4). This reliably prevents the surface of the substrate W1 from being exposed during the paddle rinse step (step S4).

[0106] When a predetermined rinsing process time has elapsed since the start of DIW discharge, the control device 220 closes the rinse liquid valve 216 to stop the discharge of DIW from the rinse liquid supply unit 205, and controls the second arm swing mechanism 212 to return the rinse liquid supply unit 205 to its home position after the DIW discharge has stopped.

[0107] - Replacement Step Next, the control device 220 starts the IPA liquid replacement step (low surface tension liquid replacement step; step S5). Specifically, while maintaining the rotation speed of the substrate W1 at a paddle speed (e.g., 10 rpm), the control device 220 opens the organic solvent valve 219 to discharge IPA liquid from the organic solvent supply unit 206 toward the vicinity of the rotation center of the substrate W1. The discharge flow rate of the IPA liquid from the organic solvent supply unit 206 at this time is set to, for example, 0.1 (liters / minute). The IPA liquid is supplied to the upper surface of the substrate W1, thereby gradually replacing the DIW contained in the DIW liquid film on the upper surface of the substrate W1 with the IPA liquid. As a result, a paddle-shaped liquid film of IPA liquid is formed on the upper surface of the substrate W1, covering the entire upper surface of the substrate W1.

[0108] When a predetermined IPA puddle time has elapsed since the start of the IPA liquid discharge, the control device 220 controls the spin motor 207 to accelerate the substrate W1 in stages from the puddle speed to a high rotation speed while continuing the discharge of the IPA liquid. After the substrate W1 reaches the high rotation speed, the control device 220 closes the organic solvent valve 219 to stop the discharge of the IPA liquid from the organic solvent supply unit 206, on the condition that the IPA processing time has elapsed since the start of the IPA liquid discharge.

[0109] - Drying Step When the discharge of the IPA liquid is stopped, the control device 220 executes the drying step (step S6). That is, the control device 220 maintains the rotation speed of the substrate W1 at a high rotation speed (for example, 600 to 1200 rpm). As a result, the IPA liquid adhering to the substrate W1 is shaken off, and the substrate W1 is dried. When the drying step (S6) is performed for a predetermined drying time, the control device 220 drives the spin motor 207 to stop the rotation of the substrate holder 203 (rotation of the substrate W1) (step S7). This completes the substrate processing for one substrate W1, and the processed substrate W1 is unloaded from the processing chamber 202 by the transport robot (step S8).

[0110] As described above, in the first processing example, the upper surface of the substrate W1 is continuously covered with a puddle-shaped liquid film throughout the period from the processing liquid puddle step (step S3) to the beginning of the IPA substitution step (step S5), and the upper surface of the substrate W1 is not exposed, thereby making it possible to protect the upper surface of the substrate W1 from contamination by particles.

[0111] 7 is a process diagram showing a second processing example of the substrate processing performed by the substrate processing apparatus 201. FIGS. 8A to 8E are diagrams showing the second processing example of the substrate processing performed by the substrate processing apparatus 201.

[0112] The second processing example of substrate processing shown in Fig. 7 differs from the first processing example of substrate processing shown in Fig. 5 in that a pre-wetting step (pre-supply step, step S13) is performed prior to the execution of the processing liquid puddle step (step S14). Hereinafter, the second processing example of substrate processing will be described with reference to Figs. 3, 4, and 7 to 8E, focusing on the differences from the first processing example. Note that, as with the first processing example, the second processing example will be described using oxide film etching as an example to remove an oxide film formed on the surface of a substrate W1 (a large circular substrate with an outer diameter of 200 mm or 300 mm) made of a silicon wafer.

[0113] In substrate processing, the transfer robot is controlled to load the unprocessed substrate W1 into the processing chamber 202 (see FIG. 3), and the substrate W1 is transferred to the substrate holder 203 with its surface facing upward (step S11). After the substrate W1 is held by the substrate holder 203, the spin motor 207 is controlled to start rotating the substrate W1 (step S12).

[0114] Pre-wet Step Next, the control device 220 executes the pre-wet step (step S13). The pre-wet step (S13) is a step of forming and maintaining a puddle-shaped liquid film of DIW covering the upper surface of the substrate W1. When the rotation speed of the substrate W1 reaches the puddle speed, the control device 220 controls the second arm swing mechanism 212 to move the rinse liquid supply unit 205 above the substrate W1 and position the rinse liquid supply unit 205 on the rotation center (rotation axis A1) of the substrate W1. Furthermore, when the rinse liquid supply unit 205 is positioned on the rotation center of the substrate W1, the rinse liquid valve 216 is opened to discharge DIW from the rinse liquid supply unit 205 toward the center of the upper surface of the substrate W1. The discharge flow rate of DIW from the rinse liquid supply unit 205 at this time is set to, for example, 2.0 (liters / minute). The DIW supplied to the center of the upper surface of the substrate W1 lands there and is pushed by the following DIW to spread outward over the substrate W1. Furthermore, since the rotation speed of the substrate W1 is the puddle speed and the centrifugal force acting on the DIW on the substrate W1 is smaller than the surface tension acting between the DIW and the surface of the substrate W1, the DIW supplied to the substrate W1 remains as a puddle on the substrate W1 without scattering around the substrate W1. Therefore, as shown in FIG. 8A , a puddle-shaped film 225 of DIW is formed over the entire upper surface of the substrate W1.

[0115] When a predetermined pre-wet time has elapsed since the start of DIW discharge, the control device 220 closes the rinse liquid valve 216 to stop the discharge of DIW from the rinse liquid supply unit 205, and controls the second arm swing mechanism 212 to return the rinse liquid supply unit 205 to its home position after the DIW discharge has stopped.

[0116] Etching Process Next, the control device 220 starts the processing liquid puddle process (step S14). Specifically, the control device 220 controls the first arm swing mechanism 242 to move the processing liquid supply unit 204 above the substrate W1 and position the processing liquid supply unit 204 above the center of rotation of the substrate W1. Once the processing liquid supply unit 204 is positioned above the center of rotation of the substrate W1, the control device 220 opens the processing liquid valve 214 to discharge the processing liquid from the processing liquid supply unit 204 toward the center of the upper surface of the substrate W1. The discharge flow rate of the processing liquid from the processing liquid supply unit 204 at this time is set to, for example, 2.0 (liters / minute). At the start of the processing liquid puddle process (S14), a DIW liquid film 225 is held in a puddle shape on the upper surface of the substrate W1, as shown in FIG. 8A. The processing liquid is supplied from the processing liquid supply unit 204 to the center of this DIW liquid film 225, as shown in FIG. 8B. As a result, the DIW liquid film 225 on the substrate W1 is replaced with the processing liquid sequentially, starting from the center of the substrate W1. Thereafter, the rinse liquid film 225 on the substrate W1 is entirely replaced with the processing liquid, and a puddle-shaped processing liquid film 230 is formed over the entire upper surface of the substrate W1, as shown in Fig. 8C. Because the rotation speed of the substrate W1 is maintained at the puddle speed (e.g., 10 rpm), the processing liquid discharged from the substrate W1 is suppressed or prevented from hitting peripheral members and bouncing back toward the substrate W1.

[0117] When a predetermined processing liquid processing time has elapsed since the start of discharge of the processing liquid, the control device 220 closes the processing liquid valve 214 to stop discharge of the processing liquid from the processing liquid supply unit 204, and controls the first arm swing mechanism 242 to return the processing liquid supply unit 204 to its home position after the discharge of the processing liquid has stopped. When dilute hydrofluoric acid, concentrated hydrofluoric acid, nitric hydrofluoric acid, ammonium fluoride, or the like is used as the processing liquid, the surface of the substrate W1 becomes hydrophobic after processing with the processing liquid.

[0118] Rinse Step Next, the control device 220 starts the puddle rinse step (step S15) in which the puddle-shaped processing liquid film 230 retained on the upper surface of the substrate W1 is replaced with DIW. At the time of starting the puddle rinse step (step S15), the control device 220 maintains the substrate rotation speed in the processing liquid puddle step (step S14). The control device 220 controls the second arm swing mechanism 212 to move the rinse liquid supply unit 205 above the substrate W1 and position the rinse liquid supply unit 205 over the rotation center of the substrate W1. Once the rinse liquid supply unit 205 is positioned over the rotation center of the substrate W1, the control device 220 also opens the rinse liquid valve 216 to discharge DIW from the rinse liquid supply unit 205 toward the center of the upper surface of the substrate W1. The discharge flow rate of DIW from the rinse liquid supply unit 205 at this time is set to, for example, 2.0 (liters / minute). During the period transitioning from the processing liquid puddle process (step S14) to the puddle rinse process (step S15), the rotation speed of the substrate W1 is maintained at the puddle speed, so that the entire upper surface of the substrate W1 remains covered by a puddle-shaped liquid film 230 of processing liquid throughout that period, thereby preventing the upper surface of the substrate W1 from being exposed.

[0119] 8D, when DIW is further supplied from the rinse liquid supply unit 205 toward the center of the liquid film, the liquid film 230 of the processing liquid on the substrate W1 is gradually pushed outward from the center of the substrate W1, discharged from the peripheral edge of the substrate W1, and replaced with DIW. After a predetermined time has elapsed, the entire liquid film 230 of the processing liquid on the substrate W1 is replaced by DIW, and a puddle-shaped liquid film 225 of DIW is formed over the entire upper surface of the substrate W1, as shown in FIG. 8E. This liquid film 225 of DIW washes away the processing liquid adhering to the entire upper surface of the substrate W1.

[0120] The substrate rotation speed in the paddle rinse step (step S15) is set to a paddle speed (e.g., 10 rpm). Because the centrifugal force acting on the processing liquid and DIW on the substrate W1 is small, the amount of processing liquid and DIW splashing outward from the periphery of the substrate W1 is suppressed. Because the substrate W1 is rotated at the paddle speed, a paddle-shaped DIW film 225 is maintained on the top surface of the substrate W1 throughout the paddle rinse step (step S15). This reliably prevents the surface of the substrate W1 from being exposed during the paddle rinse step (step S15).

[0121] When a predetermined rinsing process time (e.g., approximately 30 seconds) has elapsed since the start of DIW discharge, the control device 220 closes the rinse liquid valve 216 to stop the discharge of DIW from the rinse liquid supply unit 205, and controls the second arm swinging mechanism 212 to return the rinse liquid supply unit 205 to its home position after the DIW discharge has stopped.

[0122] - Replacement process and drying process After that, the control device 220 sequentially executes an IPA liquid replacement process (low surface tension liquid replacement process; step S16) and a drying process (step S17), and then the control device 220 stops the rotation of the substrate holding part 203 (rotation of the substrate W1) (step S18).

[0123] Steps S16 and S17 are equivalent to steps S5 and S6 of the first processing example shown in Fig. 5. This completes the substrate processing for one substrate W1, and the processed substrate W1 is unloaded from the processing chamber 202 by the transport robot (step S19).

[0124] 9A shows the in-plane distribution of the etching rate in the processing liquid puddle step (S14). FIG. 9B shows the in-plane distribution of the etching rate in the puddle rinse step (S15). As described above, in the second processing example, a pre-wet step (S13) is performed one step before the processing liquid puddle step (S14) to form a DIW liquid film 225 on the surface of the substrate W1. In the processing liquid puddle step (S14), as shown in FIG. 8B , the DIW is replaced with the processing liquid gradually from the center of the DIW liquid film 225 toward the periphery. Therefore, the replacement rate of the DIW with the processing liquid gradually decreases from the center toward the periphery of the substrate W1. As a result, as shown in FIG. 9A , the etching rate in the processing liquid puddle step (S14) gradually decreases from the center of rotation of the substrate W1 toward the edge.

[0125] 8D, the processing liquid is replaced with DIW in the processing liquid film 230 from the center toward the periphery, so that the replacement rate of the processing liquid with DIW gradually decreases from the center toward the periphery of the substrate W1. As a result, the etching rate in the puddle rinse step (S15) gradually increases from the center toward the edge of the substrate W1, as shown in FIG. 9B, which is the opposite of that in the processing liquid puddle step (S14).

[0126] In this way, by combining the two steps (S14, S15) with different etching characteristics, the etching characteristics of the two steps are offset. As a result, the difference in etching rate between the center and the peripheral edge of the substrate W1 is reduced. As a whole, the substrate processing (etching process) including both the processing liquid puddle step (S14) and the puddle rinse step (S15) can maintain in-plane uniformity of the etching rate, and the upper surface (front surface) of the substrate W1 can be uniformly etched.

[0127] 10 is a process diagram showing a third processing example of substrate processing performed by the substrate processing apparatus 201. The third processing example shown in FIG. 10 differs from the first processing example shown in FIG. 5 and the second processing example shown in FIG. 7 in that the supply position of DIW from the rinsing liquid supply unit 205 on the substrate W1 is scanned during the paddle rinse process (S4, S15). Specifically, from the start to the end of the paddle rinse process (S4, S15), the control device 220 controls the second arm swing mechanism 212 to move the rinsing liquid supply unit 205 along the top surface of the substrate W1. In this case, for example, a half scan (reciprocating) method is employed in which the supply position of DIW from the rinsing liquid supply unit 205 on the substrate W1 is scanned reciprocally between the center of rotation of the substrate W1 and the peripheral edge of the substrate W1.

[0128] In the puddle rinse steps (S4, S15), the supply position of the DIW on the substrate W1 is scanned, thereby agitating the liquid film (a mixed liquid film of the processing liquid and the DIW) on the upper surface of the substrate W1, thereby improving the efficiency of replacing the processing liquid with the DIW. As a result, the rinsing efficiency can be improved in the puddle rinse steps (S4, S15). Furthermore, as shown in parentheses in FIG. 10 , the supply position of the processing liquid from the processing liquid supply unit 204 on the substrate W1 may be scanned during the processing liquid puddle steps (S3, S14). Specifically, from the start to the end of the processing liquid puddle steps (S3, S14), the control device 220 controls the first arm swinging mechanism 242 to move the processing liquid supply unit 204 along the upper surface of the substrate W1. In this case, for example, a half scan (reciprocating) method is employed in which the supply position of the processing liquid from the processing liquid supply unit 204 on the substrate W1 reciprocates between the rotation center of the substrate W1 and the peripheral edge of the substrate W1.

[0129] In the processing liquid puddle process (S3, S14), the supply position of the processing liquid on the substrate W1 is scanned, so that the liquid film of the processing liquid on the upper surface of the substrate W1 is agitated and fresh processing liquid immediately after being ejected from the processing liquid supply unit 204 comes into contact with the upper surface of the substrate, thereby improving the processing efficiency of the processing liquid (etching efficiency if the processing liquid is an etching liquid as described above) in the processing liquid puddle process (S3, S14).

[0130] 11 is a process diagram showing a fourth processing example of substrate processing performed by the substrate processing apparatus 201. In this fourth processing example, during a certain period of time during which the paddle rinse process (S4, S15) is performed, the supply position of DIW from the rinse liquid supply unit 205 on the substrate W1 is stationary at the center of rotation of the substrate W1, and after the certain period has elapsed, the supply position of DIW on the substrate W1 is scanned back and forth between the center of rotation of the substrate W1 and the peripheral edge of the substrate W1, as in the third processing example.

[0131] 11 , during a certain period during which the processing liquid puddle step (S3, S14) is performed, the supply position of the processing liquid from the processing liquid supply unit 204 on the substrate W1 may be stationary at the center of rotation of the substrate W1, and after the certain period has elapsed, the supply position of the processing liquid on the substrate W1 may be scanned back and forth between the center of rotation of the substrate W1 and the peripheral edge of the substrate W1, as in the third processing example.

[0132] In the fourth processing example, the supply position of the DIW or processing liquid may be scanned first, and then the supply position of the DIW or processing liquid may be stationary and positioned on the center of rotation of the substrate W1.

[0133] As described above, according to this embodiment, in the processing liquid puddle steps (S3, S14), a liquid film of processing liquid covering the upper surface of the substrate W1 is maintained. Following completion of the processing liquid puddle steps (S3, S14), the liquid film of processing liquid maintained on the upper surface of the substrate W1 is replaced with DIW. This rinse liquid replacement maintains a liquid film of DIW covering the upper surface of the substrate W1, and this rinse liquid film washes away the processing liquid adhering to the upper surface of the substrate W1 (puddle rinse steps S4, S15). Because the liquid film of processing liquid maintained on the substrate W1 is replaced with DIW and a liquid film of DIW is formed on the upper surface of the substrate W1, the upper surface of the substrate W1 is not exposed during the transition from the processing liquid process to the rinse process. This allows the processing liquid process and the rinse process to be performed on the upper surface of the substrate W1 without going through a process that exposes the upper surface of the substrate W1.

[0134] Furthermore, the rotation speed of the substrate W1 is maintained at the paddle speed (e.g., 10 rpm) throughout the entire treatment period. This suppresses or prevents the treatment liquid discharged from the substrate W1 from hitting peripheral components and bouncing back toward the substrate W1. This suppresses or prevents particles contained in the bouncing back treatment liquid from adhering to the substrate W1. This increases the cleanliness of the substrate W1.

[0135] While one embodiment of the single-wafer processing substrate processing apparatus has been described above, other embodiments are also possible. For example, in the above embodiment, the supply of the rinse liquid (DIW) in the puddle rinse step (S4, S15) is performed using only the rinse liquid supply unit 205. However, the supply method of the rinse liquid (DIW) shown in FIGS. 12A to 12C and 13 may also be adopted.

[0136] 12A , a nozzle 271 for supplying DIW to the center of the substrate W1 is provided in addition to the rinse liquid supply unit 205. The nozzle 271 is, for example, a straight nozzle that discharges DIW as a rinse liquid in a continuous stream and is fixedly disposed above the substrate holder 203 (see FIG. 3 ) with its discharge port facing the peripheral edge of the substrate W1. DIW is supplied to the nozzle 271 from a DIW supply source. During the puddle rinse step (S4, S15), not only is DIW supplied from the rinse liquid supply unit 205 to the central part of the substrate W1, but also DIW from the nozzle 271 is supplied to the peripheral edge of the substrate W1. Therefore, an increase in the flow rate of DIW supplied to the substrate W1 is achieved during the puddle rinse step (S4, S15).

[0137] 12A , the modified example of FIG. 12B differs from the modified example of FIG. 12A in that a nozzle 282 having the above-described scanning configuration and discharging DIW is provided instead of the nozzle 271. DIW is supplied to each nozzle 282 from a DIW supply source. Prior to the execution of the paddle rinse step (S4, S15), the nozzle 282 is positioned so that its discharge port faces the peripheral edge of the substrate W1. During the execution of the paddle rinse step (S4, S15), as in the case of FIG. 12A , not only is DIW supplied from the rinse liquid supply unit 205 to the center of the substrate W1, but also DIW from the nozzle 282 (the nozzle is also referred to as a rinse liquid supply unit) is supplied to the peripheral edge of the substrate W1.

[0138] 12A in that a nozzle 291 having the above-described scan nozzle configuration and two outlets 292 and 293 is provided instead of the rinse liquid supply unit 205. The outlets 292 and 293 are each provided facing downward. DIW is supplied to the nozzle 291 from a DIW supply source via a valve (not shown), and when the valve is open, the DIW is each discharged downward from the outlets 292 and 293.

[0139] In the modification shown in Figure 13, a ceiling nozzle 2101 disposed on the ceiling wall of the processing chamber 202 (see Figure 3) is used to supply DIW to the surface of the substrate W1 during the puddle rinse process (S4, S15). This ceiling nozzle 2101 ejects DIW as cleaning water onto an arm that swingably supports the nozzle and a shielding member that shields the space above the surface of the substrate W1 from its surroundings. The ceiling nozzle 2101 is, for example, a straight nozzle that ejects DIW in a continuous stream and is fixedly disposed above the substrate holder 203 (see Figure 3) with its ejection port facing near the center of rotation of the substrate W1. DIW is supplied to the ceiling nozzle 2101 from a DIW supply source.

[0140] When the puddle rinse process (S4, S15) is started, the discharge of DIW from the ceiling nozzle 2101 is started while the discharge rate of DIW from the rinse liquid supply unit 205 is maintained at the same flow rate as before. As a result, during the puddle rinse process (S4, S15), not only the DIW from the rinse liquid supply unit 205 but also the DIW from the ceiling nozzle 2101 is supplied to the center of the substrate W1. Therefore, an increase in the flow rate of DIW supplied to the substrate W1 is realized during the puddle rinse process (S4, S15).

[0141] 12A to 12C and 13 show modified examples of the supply method of the rinsing liquid (DIW) in the puddle rinse step (S4, S15), but the modified examples shown in FIGS. 12A to 12C and 13 can also be used for the supply of the processing liquid in the processing liquid puddle step (S3, S14). In the first and second processing examples, the transition from the processing liquid puddle step (S3, S14) to the puddle rinse step (S4, S15) involves first returning the processing liquid supply unit 204 to its home position, and then moving the rinsing liquid supply unit 205 from its home position to a position facing the substrate W1. Therefore, the supply of liquid to the surface of the substrate W1 is temporarily stopped. However, when the rinse liquid supply unit 205 and the processing liquid supply unit 204 are attached to the same second arm 210, the supply of the rinse liquid from the rinse liquid supply unit 205 can be started immediately after the processing liquid supply unit 204 stops supplying the processing liquid. In this case, the liquid continues to be supplied to the liquid film of the processing liquid on the upper surface of the substrate, so that exposure of the upper surface of the substrate W1 can be more reliably prevented during the transition from the processing liquid puddle step (steps S3, S14) to the puddle rinse step (steps S4, S15).

[0142] In the third and fourth processing examples, a half scan is used to scan the supply position of the DIW or processing liquid on the substrate W1, but a full scan (variable scan) may be used to move the substrate W1 between one peripheral edge and another peripheral edge located on either side of the rotation center of the substrate W1. Furthermore, the scan may not be a reciprocating scan in which the DIW or processing liquid is supplied while the substrate W1 is moving back and forth, but may be a one-way scan in which the DIW or processing liquid is supplied from the processing liquid supply unit 204 only while the substrate W1 is moving in one direction.

[0143] In addition, in the above-described processing examples, it has been described that the processing liquid supply unit 204 and the rinse liquid supply unit 205 both have a scan nozzle configuration, but the processing liquid supply unit 204 or the rinse liquid supply unit 205 may be fixedly disposed relative to the substrate holding unit 203. In addition, it has been described that the puddle speed of the substrate W1 in the processing liquid puddle step (S3, S14) and the puddle speed of the substrate W1 in the puddle rinse step (S4, S15) are equal to each other, but these puddle speeds may be different from each other.

[0144] In the above-described processing examples, the processing liquid puddle steps (S3, S14) are performed throughout the entire processing period of the processing liquid treatment on the substrate W1, but the processing liquid puddle steps (S3, S14) only need to be performed at least at the end of the processing liquid treatment, and do not necessarily need to be performed throughout the entire processing period. In addition, the pre-wet step (S13) is described as rotating the substrate W1 at a puddle speed to maintain a puddle-like film of DIW over the entire upper surface of the substrate W1, but in the pre-wet step (S13), it is sufficient that a film of DIW is maintained on the surface of the substrate W1, and for example, DIW may be supplied to the upper surface of the substrate W1 at a high flow rate and the substrate W1 may be rotated at a relatively high rotation speed (higher than the puddle speed).

[0145] The above description uses DIW as a rinse liquid. However, the rinse liquid is not limited to DIW. Carbonated water, electrolytic ionized water, ozone water, diluted hydrochloric acid water (e.g., about 10 to 100 ppm), reduced water (hydrogen water), etc. can also be used as a rinse liquid. Furthermore, in addition to IPA, organic solvents with low surface tension such as methyl alcohol, ethyl alcohol, acetone, and HFE (hydrofluoroether) can also be used.

[0146] Furthermore, the substrate processing apparatus 201 of the present disclosure can be widely used for post-rinse processing, not limited to post-rinse processing during substrate processing to remove a silicon oxide film from the surface of the substrate W1. However, the effects of the present disclosure are particularly pronounced when the surface of the substrate W1 is hydrophobic. Examples of processing for a substrate W1 with a hydrophobic surface include a process for removing a silicon oxide film and a process for removing a resist.

[0147] In addition, various design modifications can be made within the scope of the claims.

[0148] <Batch-Type Substrate Processing Apparatus> The batch-type substrate processing apparatus is a processing method in which a plurality of substrates are processed at the same time. An embodiment of the batch-type substrate processing apparatus will be described below.

[0149] First Embodiment In the first embodiment, the substrate processing apparatus of the present disclosure is applied to a batch-type substrate processing apparatus. Fig. 14 is a longitudinal cross-sectional view of a substrate processing apparatus 301 according to the first embodiment, taken along a plane parallel to the substrate W1. Fig. 14 also shows the configuration of piping and a control system. Fig. 15 is a longitudinal cross-sectional view of the substrate processing apparatus 301 taken along the line A-A in Fig. 14.

[0150] This substrate processing apparatus 301 is an apparatus that processes a substrate W1 with a processing liquid, then performs surface substrate processing with a rinse liquid to remove the processing liquid, and then dries the substrate W1 with IPA, which is an organic solvent, and is mainly equipped with a chamber 310, a processing bath 320, a lifter 330, a processing liquid supply system 340a, a gas supply system 350, a drainage system 360, an exhaust system 370, and a control unit 380. The substrate W1 can be any substrate disclosed herein.

[0151] [310. Chamber] The chamber 310 is a housing that houses the processing bath 320, the lifter 330, the gas supply nozzle 351, etc. The upper part 311 of the chamber 310 can be opened and closed by a sliding opening and closing mechanism (not shown). When the upper part 311 is open, the substrate W1 can be loaded and unloaded through the open part, and when the upper part 311 is closed, the interior can be made into an airtight space.

[0152] [320. Processing Tank] The processing tank 320 is a container for storing a processing liquid such as a rinse liquid. Two processing liquid discharge nozzles 321 are provided near the bottom of the processing tank 320. The two processing liquid discharge nozzles 321 are provided facing both sides of the substrate W1 immersed in the processing tank 320, and the processing liquid is discharged from the processing liquid discharge nozzles 321 obliquely upward into the processing tank 320 as indicated by arrow AR1 in FIG. 14 . The top of the processing tank 320 is open, and an outer tank 322 is provided at the upper end of the outer surface. The processing liquid discharged from the processing liquid discharge nozzles 321 flows upward inside the processing tank 320 and overflows from the opening at the top into the outer tank 322.

[0153] [330. Lifter] The lifter 330 is a mechanism for holding and raising and lowering multiple substrates W1, and includes a lifter head 331, a holding plate 332, and three holding rods 333. The holding rods 333, which are fixed between the lifter head 331 and the holding plate 332, have multiple holding grooves (not shown), and the multiple substrates W1 are collectively held in an upright position on the holding grooves. Furthermore, a lifter drive unit 334, which includes a servo motor, a timing belt, etc., is connected to the lifter 330. When the lifter drive unit 334 is operated, the lifter 330 rises and falls, and the multiple substrates W1 rise and fall as indicated by arrow AR2 between an immersion position L (position indicated by a virtual line in FIG. 14 ) in the processing bath 320 and a lifting position H1 (position indicated by a solid line in FIG. 14 ) above the processing bath 320 in the chamber 310. By raising the lifter 330 to the lifted position H1 and opening the upper portion 311 of the chamber 310, the substrate W1 can be transferred between the lifter 330 and a substrate transport robot outside the apparatus.

[0154] [340a. Processing Liquid Supply System] The processing liquid supply system 340a is a piping system for supplying a processing liquid and a rinsing liquid to the processing liquid discharge nozzle 321. The piping system for supplying the rinsing liquid to the processing liquid discharge nozzle 321 includes a pure water supply source 341, a pure water valve 342, and a pipe 343, and further includes a gas dissolver 344, a carbon dioxide supply source 345, a gas valve 346, and a pipe 347. The piping system for supplying the processing liquid to the processing liquid discharge nozzle 321 includes a processing liquid supply source 3401, a processing liquid valve 3402, and a pipe 3403.

[0155] A pipe 343 having a pure water valve 342 inserted therein extends from the pure water supply source 341 and is connected to the processing liquid discharge nozzle 321. A gas dissolver 344 is inserted in the pipe 343 downstream of the pure water valve 342. On the other hand, a pipe 347 having a gas valve 346 inserted therein extends from the carbon dioxide supply source 345 and is connected to the gas dissolver 344.

[0156] A pipe 3403 having a processing liquid valve 3402 inserted therein extends from the processing liquid supply source 3401. The pipe 3403 joins with the pipe 343 downstream of the gas dissolver 344. However, the pipe 3403 may also join with the pipe 343 upstream of the gas dissolver 344. Although only one processing liquid supply source 3401 is shown here, multiple types of processing liquid supply sources may be provided.

[0157] In this configuration, when the pure water valve 342 is opened, pure water supplied from the pure water supply source 341 flows into the gas dissolver 344. When the gas valve 346 is opened, carbon dioxide is supplied to the gas dissolver 344. The gas dissolver 344 pressurizes and dissolves the supplied carbon dioxide in pure water flowing in through the pipe 343 to produce a rinse liquid. This rinse liquid obtained by dissolving carbon dioxide in pure water (hereinafter referred to as "carbon dioxide-dissolved rinse liquid rC") is supplied to the processing liquid discharge nozzle 321 through the pipe 343. Note that the configuration for obtaining the carbon dioxide-dissolved rinse liquid rC in the processing tank 320 is not limited to the configuration in which the gas dissolver 344 is inserted in the pipe 343 through which pure water flows. For example, a carbon dioxide supply port may be formed in the processing tank 320 and a carbon dioxide supply source 345 may be connected to the gas dissolver 344. In this case, carbon dioxide is blown into the pure water stored in the processing tank 320 to obtain the carbon dioxide-dissolved rinse liquid rC in the processing tank 320.

[0158] Furthermore, in this configuration, when the processing liquid valve 3402 is opened, the processing liquid supplied from the processing liquid supply source 3401 is supplied to the processing liquid discharge nozzle 321 through the pipe 3403 and the pipe 343. The processing liquid supplied from the processing liquid supply source 3401 is a processing liquid for cleaning the substrate W1. In addition to the processing liquid disclosed herein, the processing liquid may be, for example, APM (Ammonia-Hydrogen Peroxide Mixture), HPM (Hydrochloric acid-Hydrogen Peroxide Mixture), FPM (Hydrofluoric acid-Hydrogen Peroxide Mixture), DHF (Diluted Hydrofluoric Acid), O ３ / DIW (ozone water) or the like may be used selectively as appropriate depending on the type of film to be formed on the substrate W1.

[0159] [350. Gas Supply System] Gas supply system 350 is a piping system for supplying nitrogen gas and IPA gas into chamber 310. It includes gas supply nozzles 351 provided on both sides of the upper portion of chamber 310 to supply predetermined gases diagonally downward, an IPA supply source 352, an IPA valve 353, a nitrogen supply source 354, a nitrogen valve 355, and pipes 356 and 357. Pipe 356, into which IPA valve 353 is inserted, extends from IPA supply source 352, and pipe 357, into which nitrogen valve 355 is inserted, extends from nitrogen supply source 354. Pipe 357 merges with pipe 356 downstream of IPA valve 353. After the merger, pipe 356 is connected to gas supply nozzle 351. In this configuration, when IPA valve 353 is opened, IPA gas is discharged from gas supply nozzle 351, and the IPA gas is supplied into chamber 310. Furthermore, when the nitrogen valve 355 is opened, nitrogen gas is discharged from the gas supply nozzle 351 and supplied into the chamber 310 .

[0160] [360. Drainage System] Drainage system 360 is a piping system for draining the processing liquid in processing tank 320, and includes pipes 362 and 363 and a drainage valve 361. Pipe 362, into which drainage valve 361 is inserted, is connected to the bottom of processing tank 320. Pipe 363 is also connected to outer tank 322. In this configuration, when drainage valve 361 is opened, the processing liquid in processing tank 320 is quickly drained to the drainage line through pipe 362. Furthermore, processing liquid that has overflowed from processing tank 320 to outer tank 322 is drained to the drainage line through pipe 363.

[0161] [370. Exhaust System] Exhaust system 370 is a piping system for exhausting the atmosphere inside chamber 310, and includes exhaust valve 371, exhaust pump 372 which is a pressure reduction pump, and piping 373. Exhaust valve 371 and exhaust pump 372 are inserted into piping 373 which is connected to the inside of chamber 310. In this configuration, when exhaust valve 371 is opened and exhaust pump 372 is driven, the atmosphere inside chamber 310 is exhausted. Furthermore, when the inside of chamber 310 is an airtight space, the inside of chamber 310 is depressurized.

[0162] [380. Control Unit] The control unit 380 is electrically connected to the lifter driving unit 334, the pure water valve 342, the processing liquid valve 3402, the gas valve 346, the gas dissolving unit 344, the IPA valve 353, the nitrogen valve 355, the drain valve 361, the exhaust valve 371, the exhaust pump 372, etc., and controls the operation of these components.

[0163] The processing operation of the first embodiment will be described below.

[0164] 16 to 18 are diagrams showing the substrate processing apparatus 301 at various stages of the processing operation, with Fig. 16 showing the stage of surface substrate processing with a rinse liquid, Fig. 17 showing the stage of lifting the substrate W1 from the processing bath 320 after the substrate processing with the rinse liquid, and Fig. 18 showing the stage of drying processing using IPA, an organic solvent. The operation of the substrate processing apparatus 301 progresses by the control unit 380 controlling the lifter driving unit 334, the pure water valve 342, the processing liquid valve 3402, the gas valve 346, the gas dissolver 344, the IPA valve 353, the nitrogen valve 355, the drain valve 361, the exhaust valve 371, the exhaust pump 372, etc.

[0165] - Substrate placement process First, the lifter 330 receives a plurality of substrates W1 from a transport robot (not shown), thereby starting surface processing of the substrates W1 in the substrate processing apparatus 301. These substrates W1 may be the substrates disclosed herein, and fine patterns for forming electronic circuits may be formed on the surfaces of these substrates W1. The surfaces of these patterns may also be metal.

[0166] Next, the lifter 330 descends while holding the plurality of substrates W1 together, and the upper part 311 of the chamber 310 is closed. At this time, the nitrogen valve 355 (see FIG. 14) is open, and nitrogen gas is supplied from the gas supply nozzle 351. That is, the inside of the chamber 310 is placed in a nitrogen atmosphere. Subsequent surface substrate processing of the substrates W1 with the processing liquid and rinse liquid proceeds in a nitrogen atmosphere.

[0167] - Etching process When the plurality of substrates W1 reach the immersion position L shown in Figure 16, the lifter 330 stops while fixing and holding the plurality of substrates W1. At this time, the processing liquid valve 3402 (see Figure 14) is open, and the processing liquid is stored in the processing bath 320. Furthermore, the processing liquid continues to be supplied and discharged from the processing liquid discharge nozzle 321, and the processing liquid continues to overflow into the outer bath 322 from the opening at the top of the processing bath 320. In other words, the plurality of substrates W1 are fixed and held in a state immersed in the processing liquid stored in the processing bath 320. Note that the supply of the processing liquid to the processing bath 320 may be started when the plurality of substrates W1 are fixed and held at the immersion position L.

[0168] While maintaining a state in which a plurality of substrates W1 are immersed in the processing liquid stored in the processing bath 320, the processing liquid is continuously supplied into the processing bath 320 from the processing liquid discharge nozzle 321, thereby performing front surface substrate processing of the substrates W1 with the processing liquid. When substrate processing is performed with a plurality of types of processing liquid, the various processing liquids are supplied in a predetermined order into the processing bath 320. When front surface substrate processing of the substrates W1 with the processing liquid is completed, the drain valve 361 (see FIG. 14 ) is opened to drain the processing liquid stored in the processing bath 320.

[0169] - Rinse Step After the processing liquid in the processing tank 320 has been drained, the pure water valve 342 (see FIG. 14) and the gas valve 346 (see FIG. 14) are opened, and the carbon dioxide-dissolved rinse liquid rC is supplied into the processing tank 320 from the processing liquid discharge nozzle 321. That is, as shown in FIG. 16, while maintaining the plurality of substrates W1 at the immersion position L, the carbon dioxide-dissolved rinse liquid rC is stored in the processing tank 320, and further, the carbon dioxide-dissolved rinse liquid rC is allowed to continue overflowing from the opening at the top of the processing tank 320 into the outer tank 322. However, the carbon dioxide concentration of the carbon dioxide-dissolved rinse liquid rC is, for example, 300 ppm.

[0170] The surface of the substrate W1 is treated with the rinse liquid by continuously supplying the carbon dioxide-dissolved rinse liquid rC into the treatment tank 320 while maintaining a state in which a plurality of substrates W1 are immersed in the carbon dioxide-dissolved rinse liquid rC stored in the treatment tank 320. However, dissolving carbon dioxide does not reduce the rinsing ability of pure water, and the treatment liquid is removed, so that the rinse liquid has the same cleaning effect as pure water.

[0171] - Replacement Step When the surface substrate processing of the substrates W1 with the rinse liquid is completed, the lifter 330 rises while holding the plurality of substrates W1 together, as shown in Fig. 17. At this time, the nitrogen valve 355 (see Fig. 14) is closed, and the IPA valve 353 (see Fig. 14) is opened, so that IPA gas is supplied from the gas supply nozzle 351 instead of nitrogen gas. That is, the nitrogen gas atmosphere inside the chamber 310 is replaced with an IPA gas atmosphere.

[0172] When the lifter 330 lifts the substrate W1 from the carbon dioxide-dissolved rinse liquid rC stored in the processing bath 320 into an IPA gas atmosphere, IPA condenses on the surface portion P of the substrate W1 that emerges above the liquid surface. In other words, the carbon dioxide-dissolved rinse liquid rC adhering to the surface portion P is replaced with IPA.

[0173] According to the inventor's research, when pure water containing dissolved carbon dioxide is used as the rinse liquid, the amount of rinse liquid remaining between fine patterns formed on the substrate when the substrate is removed after processing with the rinse liquid is smaller than when pure water is used as the rinse liquid. It has also been confirmed that uneven residue of the rinse liquid is less likely to occur. Therefore, in this embodiment, in which carbon dioxide-dissolved rinse liquid rC is used as the rinse liquid, the amount of carbon dioxide-dissolved rinse liquid rC remaining between patterns formed on the surface portion P is smaller than when pure water is used as the rinse liquid, and uneven residue of the rinse liquid is also less likely to occur.

[0174] Alternatively, instead of lifting up the substrate W1, the liquid level in the processing bath 320 may be lowered to raise the substrate W1 relatively above the liquid level of the carbon dioxide-dissolved rinse liquid rC and expose it to the IPA atmosphere. That is, while the substrate W1 is held at the immersion position L, the drain valve 361 (see FIG. 14 ) may be opened to drain the carbon dioxide-dissolved rinse liquid rC from the processing bath 320, and after the substrate W1 is exposed, the substrate W1 may be lifted up by the lifter 330. In this case, too, the amount of rinse liquid remaining between patterns on the surface of the substrate W1 exposed from the rinse liquid is smaller than when pure water is used as the rinse liquid.

[0175] 18, the lifter 330 stops while holding the substrates W1 in place. Then, with the exhaust valve 371 (see FIG. 14) open, the exhaust pump 372 is driven to exhaust the atmosphere in the chamber 310, thereby reducing the pressure inside the chamber 310.

[0176] When the pressure inside the chamber 310 is reduced, the IPA condensed on the surface of the substrate W1 held at the lifting position H1 is rapidly vaporized, and the surface of the substrate W1 is dried.

[0177] Here, uneven liquid residue between patterns when the wafer is lifted from the rinse liquid, for example, uneven residue of rinse liquid between cylindrical capacitors, is less likely to occur, so the cylinders are less likely to collapse during the drying process.

[0178] That is, when the substrate W1 is lifted from the carbon dioxide-dissolved rinse solution rC, uneven liquid residue as shown in FIG. 20A is unlikely to occur between the cylindrical capacitors C1, C2, and C3 formed on the substrate W1, resulting in the state shown in FIG. 21A. Therefore, the forces f1 and f2 due to surface tension are reduced, and the combined force F, biased in a specific direction, is also unlikely to occur. Therefore, as shown in FIG. 21B, the cylinders do not collapse during the drying process. According to the inventor's research, when pure water was used as the rinse solution, approximately 20 cylindrical capacitors collapsed per chip. However, by using pure water with carbon dioxide dissolved therein as the rinse solution, the number of cylinder collapses per chip was confirmed to be reduced to approximately one. In other words, by using the carbon dioxide-dissolved rinse solution rC as the rinse solution, it can be said that cylinder collapse is reduced by approximately 95%.

[0179] Furthermore, since the amount of rinse solution remaining in the trench capacitor when it was removed from the rinse solution was small, poor drying in the trench was unlikely to occur, meaning that problems caused by residual water R between patterns during the drying process were unlikely to occur.

[0180] When the drying process is completed, the lifter 330 transfers the substrate W1 held at the lifting position H1 to a transport robot (not shown). This completes the surface treatment operation of the substrate W1 in the substrate processing apparatus 301.

[0181] Second Embodiment Similar to the first embodiment, the second embodiment is an embodiment in which the substrate processing apparatus of the present disclosure is applied to a batch-type substrate processing apparatus. Fig. 19 is a diagram showing a processing liquid supply system 340b of the substrate processing apparatus according to the second embodiment. However, the same components as those in the processing liquid supply system 340a of the substrate processing apparatus 301 according to the first embodiment are denoted by the same reference numerals.

[0182] The substrate processing apparatus according to the second embodiment is an apparatus that processes the substrate W1 with a processing liquid, then performs final substrate processing with a rinse liquid to remove the processing liquid, and then dries the substrate using IPA, an organic solvent. However, it differs from the substrate processing apparatus 301 in that it performs final substrate processing using a rinse liquid obtained by dissolving hydrogen in pure water.

[0183] [340b. Processing Liquid Supply System] The configuration of the substrate processing apparatus according to the second embodiment is substantially the same as that of the substrate processing apparatus 301 according to the first embodiment. However, it differs from the substrate processing apparatus 301 in that it includes a processing liquid supply system 340b shown in FIG. 19 as a piping system for supplying a rinsing liquid to the processing liquid discharge nozzle 321. The processing liquid supply system 340b has substantially the same configuration as the processing liquid supply system 340a in the substrate processing apparatus 301, but includes a hydrogen supply source 395 instead of the carbon dioxide supply source 345.

[0184] In the processing liquid supply system 340b configured as described above, when the pure water valve 342 is opened, pure water supplied from the pure water supply source 341 flows into the gas dissolver 344. When the gas valve 346 is opened, hydrogen is supplied to the gas dissolver 344. The gas dissolver 344 generates a rinse liquid by pressurizing and dissolving the supplied hydrogen in the pure water that flows in through a pipe 343. This rinse liquid (hereinafter referred to as "hydrogen-dissolved rinse liquid rH") obtained by dissolving hydrogen in pure water is supplied to the processing liquid discharge nozzle 321 through the pipe 343. Of the various modifications described in the first embodiment, those that are not inconsistent with the configuration of the second embodiment are also applied to the second embodiment.

[0185] The processing operation of the second embodiment will be described below.

[0186] <Substrate Processing Operation> The substrate processing operation of the substrate processing apparatus according to the second embodiment is substantially the same as that of the substrate processing apparatus 301 according to the first embodiment. However, it differs from the substrate processing apparatus 301 in that a hydrogen-dissolved rinse solution rH is used as the rinse solution instead of a carbon dioxide-dissolved rinse solution rC. However, the hydrogen concentration of the hydrogen-dissolved rinse solution rH used as the rinse solution is, for example, 1 ppm.

[0187] In addition, even in the surface substrate treatment using the hydrogen-dissolved rinse solution rH, the rinsing ability of pure water is not reduced by dissolving hydrogen, and the same cleaning effect as pure water can be obtained as a rinse solution to remove the treatment solution.

[0188] Furthermore, according to the inventor's research, when pure water containing dissolved hydrogen is used as the rinse liquid, the amount of rinse liquid remaining between fine patterns formed on the substrate when the substrate is lifted after processing with the rinse liquid is confirmed to be less than when pure water is used as the rinse liquid. It has also been confirmed that uneven residue of the rinse liquid is less likely to occur. Therefore, in this embodiment, in which hydrogen-dissolved rinse liquid rH is used as the rinse liquid, the amount of hydrogen-dissolved rinse liquid rH remaining between patterns formed on the surface portion of the substrate W1 lifted from the rinse liquid is less than when pure water is used as the rinse liquid, and uneven residue of the rinse liquid is also less likely to occur. As a result, problems caused by water residue R between patterns, such as cylinder collapse and insufficient drying in trenches, are less likely to occur during the drying process.

[0189] <Others> In the above embodiments, IPA gas is used as the organic solvent gas for drying. However, instead of IPA gas, other gases such as alcohols may be used as the organic solvent gas for drying.

[0190] Furthermore, the first and second embodiments are so-called one-bath type substrate processing apparatuses in which both processing liquid processing and final substrate processing using a rinse liquid are performed in a single processing tank, but the technology disclosed herein can also be applied to so-called multi-tank type substrate processing apparatuses in which processing liquid processing and final substrate processing using a rinse liquid are performed in different processing tanks.

[0191] The substrate processing solution, substrate processing method, and substrate processing apparatus of the present disclosure have been described above, but these are merely typical examples. Therefore, those skilled in the art will easily understand that the substrate processing solution, substrate processing method, and substrate processing apparatus of the present disclosure are not limited to these examples, and that various embodiments are possible.

[0192] The present disclosure will be described in detail below with reference to examples, but the present disclosure is not limited to these examples.

[0193] <Test Method> The test procedure is as follows.

[0194] [Thermal-SiO ２ Measurement of etching rate] Thermal-SiO ２ In measuring the etching rate, the blanket and the narrow space were prepared as follows.

[0195] [Blanket] Thermal-SiO2 with a thickness of about 500 nm is applied to the top surface of the substrate. ２ A blanket wafer was prepared in which the above-mentioned etching process was carried out for 3 minutes using an evaluation chemical solution (chemical solution temperature: 25° C.) according to the examples and comparative examples described below.

[0196] Next, Thermal-SiO ２ The etching amount of the blanket was measured using an optical film thickness measuring device (Nanospec II, manufactured by Onto Innovation Inc.). ２ The etching rate of the thermal-SiO blanket was calculated according to the following formula: ２ Etching rate (nm / min) = etching amount (nm) / etching time (min)

[0197] [Narrow Space] The structure shown in FIG. 1C is used to remove a portion (silicon thermal oxide film (Thermal-SiO ２ Substrates with different film thicknesses of 10 nm, 5 nm, and 3 nm were prepared. These substrates were subjected to an etching treatment for 3 minutes using the evaluation chemicals (chemical temperature: 25° C.) according to the examples and comparative examples described below.

[0198] Next, the etching amount of the part to be removed shown in FIG. 1C was measured by observation using a scanning electron microscope (JEOL Ltd., JSM-7800F, etc.), and the thermal-SiO ２ The etching rate of the thermal-SiO in the narrow space was calculated according to the following formula. ２Etching rate (nm / min) = measured etching amount (nm) / etching time (min)

[0199] [Thermal-SiO ２ Calculation of etching rate ratio] Thermal-SiO ２ The etching rate ratio was calculated according to the following formula: Thermal-SiO ２ Etching rate ratio = Thermal-SiO in narrow spaces ２ Etching rate / Blanket Thermal-SiO ２ Etching Rate

[0200] [Improvement Rate] The improvement rate was calculated using Thermal-SiO ２ The etching rate ratio was used as a reference value and the improvement rate was calculated according to the following formula: Improvement rate (%) = (Thermal-SiO ２ Etching rate ratio / reference value)×100−100 If the improvement rate was 10% or more, it was judged as passing, and if the improvement rate was less than 10%, it was judged as failing.

[0201] The chemicals used in the evaluation solutions in the Examples and Comparative Examples were as follows: 50% hydrofluoric acid (manufactured by Stella Chemifa Co., Ltd., concentration 50% by weight) 40% ammonium fluoride (manufactured by Stella Chemifa Co., Ltd., concentration 40% by weight) Monoalkylamine and monoalkylamine salt (both manufactured by Tokyo Chemical Industry Co., Ltd.) These chemicals were used to prepare solutions to the concentrations shown in Tables 1 to 3, and the evaluation solutions described in Examples 1 to 13 and Comparative Examples 1 to 4 were obtained. However, unless otherwise specified, the scope of the present invention is not limited to the chemicals, blending amounts, preparation procedures, etc. described in these Examples.

[0202]

[0203]

[0204]

[0205] As can be seen from Tables 1 to 3, Examples 1 to 13 had an improvement rate of 10% or more, which is acceptable, and the substrate processing solution of the present disclosure was able to efficiently form a narrow space.

[0206] 110 Surface layer portion 111 Trench 112 Semiconductor layer 113 Insulator layer W Stacked body, stacked structure W1 Substrate W2 Portion to be removed W3 Semiconductor layer W4 Through hole W5 Exposed region W6 Narrow space W7 Microscopic region H Shortest distance D Depth DD1 Depth direction of trench TD Thickness direction of substrate Dp1 Trench depth w1 Trench width 201 Substrate processing apparatus 202 Processing chamber 203 Substrate holder 204 Processing liquid supply unit 205 Rinse liquid supply unit 206 Organic solvent supply unit 207 Spin motor 208 Spin base 209 Clamping member 210 Second arm 211 Second arm support shaft 212 Second arm swinging mechanism 213 Processing liquid supply pipe 214 Processing liquid valve 215 Rinse liquid supply pipe 216 Rinse liquid valve 218 Organic solvent supply pipe 219 Organic solvent valve 220 Control device 225 Liquid film 230 Liquid film 240 First arm 241 First arm support shaft 242 First arm swing mechanism 271 Nozzle 282 Nozzle 291 Nozzle 292 Discharge outlet 293 Discharge outlet 2101 Ceiling nozzle A1 Rotation axis 301 Substrate processing apparatus 310 Chamber 311 Upper part 320 Processing bath 321 Processing liquid discharge nozzle 322 Outer bath 330 Lifter 331 Lifter head 332 Holding plate 333 Holding rod 334 Lifter drive unit 340a Processing liquid supply system 340b Processing liquid supply system 341 Pure water supply source 342 Pure water valve 343 Piping 344 Gas dissolver 345 Carbon dioxide supply source 346 Gas valve 347 Piping 350 Gas supply system 351 Gas supply nozzle 352 IPA supply source 353 IPA valve 354 Nitrogen supply source 355 Nitrogen valve 356 Piping 357 Piping 360 Drainage system 361 Drainage valve 362 Piping 363 Piping 370 Exhaust system 371 Exhaust valve 372 Exhaust pump 373 Piping 380 Control unit 395 Hydrogen supply source 3401 Processing liquid supply source 3402 Processing liquid valve 3403 Piping AR1 Direction in which processing liquid is discharged AR2 Direction in which it moves up and down rC Carbon dioxide dissolved rinse liquid P Surface portion L Immersion position H1 Pull-up position C1 Cylindrical capacitor C2 Cylindrical capacitor C3 Cylindrical capacitor f1 Forces due to surface tensionf2 Force due to surface tension F Force biased in a specific direction R Remaining water

Claims

1. A substrate processing solution for etching silicon oxide on a substrate, the substrate processing solution comprising: (a) hydrogen fluoride; and (b) a monoalkylamine or a monoalkylamine salt, wherein the amount of the hydrogen fluoride is 10% by weight or less; the amount of the monoalkylamine or the monoalkylamine salt is 0.0001 to 0.1% by weight; and the monoalkylamine or the monoalkylamine salt has a linear alkyl group having 12 to 14 carbon atoms.

2. The substrate processing solution according to claim 1, wherein the monoalkylamine is dodecylamine or tetradecylamine.

3. The substrate processing solution according to claim 1, wherein the monoalkylamine salt is dodecylamine hydrochloride or dodecylamine acetate.

4. The substrate processing solution according to claim 1, comprising (a) hydrogen fluoride, (b) monoalkylamine or monoalkylamine salt, and (c) water.

5. The substrate processing solution according to claim 1, wherein the amount of said hydrogen fluoride is 0.5 to 7 wt %, the amount of said monoalkylamine is 0.0001 to 0.03 wt %, and the amount of said monoalkylamine salt is 0.001 to 0.05 wt %.

6. A substrate processing method comprising: bringing a substrate processing solution into contact with a portion to be removed provided on a substrate, thereby etching at least a part of the portion to be removed; and forming a narrow space on the substrate by etching at least a part of the portion to be removed, wherein the substrate processing solution contains: (a) hydrogen fluoride, and (b) a monoalkylamine or a monoalkylamine salt, the amount of the hydrogen fluoride is 10% by weight or less, the amount of the monoalkylamine or the monoalkylamine salt is 0.0001 to 0.1% by weight, and the monoalkylamine or the monoalkylamine salt has a linear alkyl group having 12 to 14 carbon atoms.

7. The substrate processing method according to claim 6, wherein the narrow space formed by etching is a recess having an opening, the shortest distance of which is 50 nm or less.

8. The substrate processing method according to claim 7, wherein the recess has a depth of 30 nm or more.

9. The substrate processing method according to claim 6, wherein a semiconductor layer is provided on the substrate and stacked on the portion to be removed, and the substrate processing solution etches at least a part of the portion to be removed between the substrate and the semiconductor layer to form the narrow space between the substrate and the semiconductor layer.

10. The substrate processing method according to claim 6, wherein the monoalkylamine is dodecylamine or tetradecylamine.

11. The substrate processing method according to claim 6, wherein the monoalkylamine salt is dodecylamine hydrochloride or dodecylamine acetate.

12. A substrate processing apparatus comprising: a processing section that brings a substrate processing solution into contact with a portion to be removed provided on the substrate, thereby etching at least a part of the portion to be removed and forming a narrow space on the substrate; wherein the substrate processing solution contains: (a) hydrogen fluoride, and (b) a monoalkylamine or a monoalkylamine salt; the amount of the hydrogen fluoride is 10% by weight or less; the amount of the monoalkylamine or the monoalkylamine salt is 0.0001 to 0.1% by weight; and the monoalkylamine or the monoalkylamine salt has a linear alkyl group having 12 to 14 carbon atoms.

13. The substrate processing apparatus according to claim 12, wherein the processing section includes: a substrate holding section that holds the substrate in a horizontal position; and a processing liquid supply section that supplies the substrate processing liquid to an upper surface of the substrate held by the substrate holding section.

14. The substrate processing apparatus of claim 12, wherein the processing section includes: a processing tank for storing the substrate processing liquid; a holding section for holding a plurality of the substrates in an upright position together; and a lifting mechanism for raising and lowering the holding section relative to the processing tank to immerse the plurality of substrates in the substrate processing liquid or to lift them out of the substrate processing liquid.

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