Cleaning method, etching method, method for manufacturing semiconductor device, and etching system

Abstract

The present invention provides: a cleaning method capable of removing at least a portion of a F- and Ge-containing substance; an etching method capable of reducing deposition of etching residues; a method for manufacturing a semiconductor device using the cleaning method and the etching method, and an etching system capable of reducing deposition of etching residues. The present invention relates to a cleaning method in which at least a portion of a F- and Ge-containing substance that is positioned on the surface of an object to be cleaned and contains fluorine atoms and germanium atoms is removed using a solution containing at least one of an acidic substance or an alkaline substance.

Description

Washing method, etching method, method for manufacturing semiconductor device, and etching system

[0001] The present disclosure relates to a washing method, an etching method, a method for manufacturing a semiconductor device, and an etching system.

[0002] As a technique for etching SiGe, a technique using ClF ４ , ２ ,

[0005] , ３ , ５ ,

[0006] , ７ , ２ , , , ６ , ５ gas or the like is known (Patent Documents 1 to 3).

[0003] Japanese Unexamined Patent Application Publication No. 2019-201102, Japanese Unexamined Patent Application Publication No. 2022-191045, Japanese Unexamined Patent Application Publication No. 2019-129313

[0004] As a result of the study by the present inventors, when etching a film containing germanium using IF ７ 、IF ５ 、BrF ５ 、BrF ３ 、MoF ６ 、GeF ２ 、GeF ４ and / or ClF, it has been newly clarified that an etching residue (for example, a F-containing and Ge-containing substance containing fluorine atoms and germanium atoms) is deposited on the wafer after etching. There is a concern that the etching residue may affect the characteristics of the semiconductor device.

[0005] The present disclosure aims to solve the above problems and provide a washing method capable of removing at least a part of the F-containing and Ge-containing substance, an etching method capable of reducing the deposition of etching residues, a method for manufacturing a semiconductor device using these methods, and an etching system capable of reducing the deposition of etching residues.

[0006] As a result of intensive studies, the present inventors have found that at least a part of the F-containing and Ge-containing substance containing fluorine atoms and germanium atoms can be removed by a solution containing at least one of an acidic substance and an alkaline substance, and have completed the present disclosure. Furthermore, as a result of intensive studies, the present inventors have found that when etching a film containing germanium, IF ７ 、IF ５ 、BrF ５ 、BrF ３ 、MoF ６ 、GeF ２ 、GeF４ We have found that even when using at least one gas selected from the group consisting of and ClF, the deposition of etching residue can be reduced by washing with a solution containing at least one of an acidic substance and an alkaline substance, and have completed this disclosure.

[0007] In other words, (1) of this disclosure relates to a cleaning method for removing at least a portion of a F-containing Ge substance containing fluorine atoms and germanium atoms located on the surface of an object to be cleaned, using a solution containing at least one of an acidic substance and an alkaline substance.

[0008] (2) of this disclosure states that the acidic substance is hydrogen fluoride, nitric acid, hydrogen peroxide, phosphoric acid, hydrochloric acid, hydrofluoric acid, sulfuric acid, oxalic acid, R １１ -COOH(R) １１ This is a monovalent hydrocarbon group which may have a hydrogen atom or a halogen atom. ), R １２ -SO ３ H(R) １２ The cleaning method according to (1) of this disclosure is a monovalent hydrocarbon group which may have a chlorine atom, a fluorine atom, or a halogen atom, and is at least one selected from the group consisting of ammonium chloride, ammonium sulfate, ammonium nitrate, aluminum chloride, aluminum sulfate, aluminum nitrate, and acidic ammonium fluoride.

[0009] The present disclosure (3) relates to the cleaning method according to the present disclosure (1), wherein the acidic substance is at least one selected from the group consisting of hydrogen fluoride, hydrofluoric acid, nitric acid, phosphoric acid, and hydrogen peroxide.

[0010] This disclosure (4) relates to the cleaning method according to this disclosure (1), wherein the acidic substance is at least one selected from the group consisting of hydrogen fluoride and nitric acid.

[0011] This disclosure (5) relates to a cleaning method according to any one of items (1) to (4) of this disclosure, wherein the alkaline substance is at least one selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, alkali metal phosphates, alkali metal acetates, alkaline earth metal hydroxides, alkaline earth metal carbonates, alkaline earth metal phosphates, alkaline earth metal acetates, ammonia, tetramethylammonium hydroxide, and compounds represented by the following general formula (1). (In general formula (1), N is a nitrogen atom. R １ This is a hydrocarbon group that may have a ring, heteroatom, or halogen atom with 1 to 10 carbon atoms. ２ , R ３ This is a hydrocarbon group which may have a hydrogen atom or a ring, heteroatom, or halogen atom having 1 to 10 carbon atoms. However, if the hydrocarbon group has 3 or more carbon atoms, it may have a branched chain structure or a cyclic structure. The heteroatom of the hydrocarbon group is a nitrogen atom, oxygen atom, sulfur atom, or phosphorus atom. Furthermore, R １ and R ２ If both are hydrocarbon groups having 1 or more carbon atoms, R １ and R ２ They may be directly bonded to form a cyclic structure. Furthermore, R １ or R ２ When R is directly bonded by a double bond to form a cyclic structure, ３ Aromatic rings may be formed even without the presence of R. １ , R ２ and R ３ (These may be the same hydrocarbon group or different hydrocarbon groups.)

[0012] This disclosure (6) relates to a cleaning method according to any one of items (1) to (4) of this disclosure, wherein the alkaline substance is at least one selected from the group consisting of alkali metal hydroxides and ammonia.

[0013] This disclosure (7) relates to a cleaning method according to any one of paragraphs (1) to (4) of this disclosure, wherein the alkaline substance is an alkali metal hydroxide.

[0014] This disclosure (8) relates to a cleaning method according to any one of paragraphs (1) to (4) of this disclosure, wherein the alkaline substance is at least one selected from the group consisting of sodium hydroxide and ammonia.

[0015] This disclosure (9) relates to a cleaning method according to any one of paragraphs (1) to (4) of this disclosure, wherein the alkaline substance is sodium hydroxide.

[0016] This disclosure (10) relates to a washing method according to any one of items (1) to (9) of this disclosure, wherein the solvent contained in the solution is at least one selected from the group consisting of water, hydrocarbons, esters, ethers, ketones, halogen-containing solvents, sulfoxide solvents, alcohols, derivatives of polyhydric alcohols, and nitrogen-containing compound solvents.

[0017] This disclosure (11) relates to a washing method according to any one of items (1) to (9) of this disclosure, wherein the solvent contained in the solution is water.

[0018] This disclosure (12) is IF ７ , IF ５ , BrF ５ , BrF ３ MoF ６ GeF ２ GeF ４ The present invention relates to an etching method comprising: a dry etching step of etching a germanium-containing film to be etched on a substrate with at least one gas selected from the group consisting of and ClF; and a cleaning step of cleaning the substrate obtained by the dry etching step with a solution containing at least one of an acidic substance and an alkaline substance.

[0019] The present disclosure (13) states that the acidic substance is hydrogen fluoride, nitric acid, hydrogen peroxide, phosphoric acid, hydrochloric acid, hydrofluoric acid, sulfuric acid, oxalic acid, R １１ -COOH(R) １１ This is a monovalent hydrocarbon group which may have a hydrogen atom or a halogen atom. ), R １２ -SO ３ H(R) １２The etching method according to this disclosure (12) is a monovalent hydrocarbon group which may have a chlorine atom, a fluorine atom, or a halogen atom, and is at least one selected from the group consisting of ammonium chloride, ammonium sulfate, ammonium nitrate, aluminum chloride, aluminum sulfate, aluminum nitrate, and acidic ammonium fluoride.

[0020] This disclosure (14) relates to the etching method according to this disclosure (12), wherein the acidic substance is at least one selected from the group consisting of hydrogen fluoride, hydrofluoric acid, nitric acid, phosphoric acid, and hydrogen peroxide.

[0021] This disclosure (15) relates to the etching method according to this disclosure (12), wherein the acidic substance is at least one selected from the group consisting of hydrogen fluoride and nitric acid.

[0022] This disclosure (16) relates to an etching method according to any one of items (12) to (15) of this disclosure, wherein the alkaline substance is at least one selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, alkali metal phosphates, alkali metal acetates, alkaline earth metal hydroxides, alkaline earth metal carbonates, alkaline earth metal phosphates, alkaline earth metal acetates, ammonia, tetramethylammonium hydroxide, and compounds represented by the following general formula (1). (In general formula (1), N is a nitrogen atom. R １ This is a hydrocarbon group that may have a ring, heteroatom, or halogen atom with 1 to 10 carbon atoms. ２ , R ３ This is a hydrocarbon group which may have a hydrogen atom or a ring, heteroatom, or halogen atom having 1 to 10 carbon atoms. However, if the hydrocarbon group has 3 or more carbon atoms, it may have a branched chain structure or a cyclic structure. The heteroatom of the hydrocarbon group is a nitrogen atom, oxygen atom, sulfur atom, or phosphorus atom. Furthermore, R １ and R ２ If both are hydrocarbon groups having 1 or more carbon atoms, R １ and R ２ They may be directly bonded to form a cyclic structure. Furthermore, R １ or R ２When R is directly bonded by a double bond to form a cyclic structure, ３ Aromatic rings may be formed even without the presence of R. １ , R ２ and R ３ (These may be the same hydrocarbon group or different hydrocarbon groups.)

[0023] This disclosure (17) relates to an etching method according to any one of paragraphs (12) to (15) of this disclosure, wherein the alkaline substance is at least one selected from the group consisting of alkali metal hydroxides and ammonia.

[0024] This disclosure (18) relates to an etching method according to any one of paragraphs (12) to (15) of this disclosure, wherein the alkaline substance is an alkali metal hydroxide.

[0025] This disclosure (19) relates to an etching method according to any one of paragraphs (12) to (15) of this disclosure, wherein the alkaline substance is at least one selected from the group consisting of sodium hydroxide and ammonia.

[0026] This disclosure (20) relates to an etching method according to any one of items (12) to (15) of this disclosure, wherein the alkaline substance is sodium hydroxide.

[0027] This disclosure (21) relates to an etching method according to any one of items (12) to (20) of this disclosure, wherein the solvent contained in the solution is at least one selected from the group consisting of water, hydrocarbons, esters, ethers, ketones, halogen-containing solvents, sulfoxide solvents, alcohols, derivatives of polyhydric alcohols, and nitrogen-containing compound solvents.

[0028] This disclosure (22) relates to an etching method according to any one of these disclosures (12) to (20), wherein the solvent contained in the solution is water.

[0029] This disclosure (23) states that the gas is IF ７ The present invention relates to the etching method described in any one of paragraphs (12) to (22).

[0030] This disclosure (24) relates to a method for manufacturing a semiconductor device, which includes a step using the cleaning method described in any one of paragraphs (1) to (11) of this disclosure or the etching method described in any one of paragraphs (12) to (23) of this disclosure.

[0031] This disclosure (25) provides a platform on which to place the object to be processed, and an IF for the object to be processed. ７ , IF ５ , BrF ５ , BrF ３ MoF ６ GeF ２ GeF ４ The present invention relates to an etching system comprising a gas supply unit that supplies at least one gas selected from the group consisting of and ClF, and a cleaning unit that brings a solution containing at least one of an acidic substance and an alkaline substance into contact with the object to be processed.

[0032] The cleaning method of this disclosure is a cleaning method that removes at least a portion of the F-containing Ge substance, which contains fluorine atoms and germanium atoms, located on the surface of the object to be cleaned, using a solution containing at least one of an acidic substance and an alkaline substance, and thus at least a portion of the F-containing Ge substance can be removed.

[0033] The etching method disclosed herein is IF ７ , IF ５ , BrF ５ , BrF ３ MoF ６ GeF ２ GeF ４ The etching method includes a dry etching step in which a germanium-containing film to be etched on a substrate is etched with at least one gas selected from the group consisting of and ClF, and a cleaning step in which the substrate obtained by the dry etching step is washed with a solution containing at least one of an acidic substance and an alkaline substance, thereby reducing the accumulation of etching residue.

[0034] The semiconductor device manufacturing method of this disclosure includes a step using the cleaning method or etching method of this disclosure. Therefore, it is possible to remove at least a portion of the F-containing Ge material or reduce the deposition of etching residue, thereby enabling the manufacture of high-quality semiconductor devices.

[0035] The etching system disclosed herein comprises a platform on which an object to be processed is placed, and an IF (Integrated Focusing) on ​​the object to be processed. ７ , IF ５ , BrF ５ , BrF ３ MoF ６ GeF ２ GeF ４ The system includes a gas supply unit that supplies at least one gas selected from the group consisting of and ClF, and a cleaning unit that brings a solution containing at least one of an acidic substance and an alkaline substance into contact with the object to be treated, thereby reducing the accumulation of etching residue.

[0036] Figure 1 is a schematic diagram showing an example of the etching apparatus of this disclosure. Figure 2 is a schematic diagram showing an example of the etching system of this disclosure.

[0037] The present disclosure will be described in detail below, but the description of the constituent elements described below is an example of an embodiment of the present disclosure and is not limited to these specific contents. It can be implemented in various ways within the scope of its gist.

[0038] In this specification, the notation "X to Y" in descriptions of numerical ranges means "X or greater and Y or less" unless otherwise specified. For example, "1 to 5 mass%" means "1 mass% or greater and 5 mass% or less".

[0039] <Cleaning Method> The cleaning method of this disclosure removes at least a portion of the F-containing Ge substance, which contains fluorine atoms and germanium atoms, located on the surface of the object to be cleaned, using a solution containing at least one of an acidic substance and an alkaline substance. This makes it possible to remove at least a portion of the F-containing Ge substance.

[0040] The reason why the above effects are obtained is not entirely clear, but it is presumed to be due to the following mechanism: By bringing a solution containing at least one of an acidic substance and an alkaline substance into contact with the F-containing Ge substance located on the surface of the object to be cleaned, the F-containing Ge substance located on the surface of the object to be cleaned reacts with the acidic substance and / or alkaline substance, and the reaction product dissolves in the solution, making it possible to remove at least a portion of the F-containing Ge substance located on the surface of the object to be cleaned.

[0041] <<Object to be cleaned>> The F-containing Ge substance located on the surface of the object to be cleaned, which contains fluorine atoms and germanium atoms, is not particularly limited as long as it contains fluorine atoms and germanium atoms. These may be used alone or in combination of two or more. In particular, IF ７ , IF ５ , BrF ５ , BrF ３ MoF ６ GeF ２ GeF ４ Preferably, the etching residue generated on the wafer after etching using ClF is a fluorine-containing Ge substance containing fluorine atoms and germanium atoms.

[0042] In 100% by mass of a fluorine-containing germanium-containing substance, the content of fluorine atoms is preferably 0.1 to 99.9% by mass. In 100% by mass of a fluorine-containing germanium-containing substance, the content of germanium atoms is preferably 0.1 to 99.9% by mass. In 100% by mass of a fluorine-containing germanium-containing substance, the total content of fluorine atoms and germanium atoms is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 99% by mass or more, and may be 100% by mass. In this specification, the content of each element (atom) in the substance is measured by X-ray photoelectron spectroscopy (XPS, ULVAC-PHI, PHI5000 VersaProbeII).

[0043] Examples of the object to be cleaned include a silicon substrate, a compound semiconductor substrate, a quartz substrate, and a glass substrate. On the surface of the object to be cleaned, in addition to the above-described F- and Ge-containing substance, a silicon film, a silicon oxide film, a silicon nitride film, a metal wiring film other than the above metals, etc. may be formed.

[0044] As long as the F- and Ge-containing substance is located on the surface of the object to be cleaned, its form of existence is not particularly limited, and it may be chemically bonded to the surface of the object to be cleaned, physically adsorbed on the surface of the object to be cleaned, or simply attached (lying) on the surface of the object to be cleaned.

[0045] The method for forming the F- and Ge-containing substance on the surface of the object to be cleaned is not particularly limited, and examples thereof include a chemical vapor deposition (CVD) method and a sputtering method. Also, IF ７ 、IF ５ 、BrF ５ 、BrF ３ 、MoF ６ 、GeF ２ 、GeF ４ and / or ClF is used to etch a film containing germanium on the substrate, whereby it is preferable to form an F- and Ge-containing substance as an etching residue on the wafer. Also, the shape of the F- and Ge-containing substance is not particularly limited, and examples thereof include a film shape, a particle shape, a lump shape, a layered shape in which a plurality of films, particles, etc. are deposited, etc. Further, when the maximum length of the F- and Ge-containing substance in the direction perpendicular to the surface of the object to be cleaned is defined as the thickness, the thickness of the F- and Ge-containing substance is not particularly limited, but for example, it can be set to a thickness of 0.1 nm or more and 1 μm or less. When the shape of the F- and Ge-containing substance is a layer in which a plurality of films, particles, etc. are deposited, the thickness of the layer is set to the above thickness.

[0046] In this specification, F-containing Ge material on the surface of the object to be cleaned is confirmed by observing a cross-section of the object to be cleaned, such as a wafer, with a scanning electron microscope (SEM, HITACHI SU-8000). Furthermore, removal of the F-containing Ge material is determined by calculating the area (%) covered by the F-containing Ge material before and after removal, with the observation area (area) set as 100%. Removal is considered successful when the removal rate using the following formula is 10% or more. Preferably, it is 50% or more, and more preferably 70% or more. (Area before removal (%) - Area after removal (%)) / (Area before removal (%)) × 100

[0047] The cleaning method of this disclosure uses a solution containing at least one of an acidic substance and an alkaline substance.

[0048] <<Solutions containing at least one of an acidic substance and an alkaline substance>> In a neutral solution with a pH of 7.0, neither an acidic nor an alkaline substance is present, or both are in a state of neutralization, and therefore cannot react with F-containing Ge substances. However, in alkaline solutions with a pH greater than 7.0 and acidic solutions with a pH less than 7.0, the alkaline substance or the acidic substance can react with F-containing Ge substances, respectively. Therefore, solutions containing at least one of an acidic substance and an alkaline substance are not particularly limited as long as they do not have a pH of 7.0. In this specification, pH means pH measured at 25°C.

[0049] If the solution is an alkaline solution with a pH greater than 7.0, the pH of the solution is preferably 11 or higher, more preferably 12 or higher, even more preferably 13 or higher, with no particular upper limit, but for example, 14 or lower. On the other hand, if the solution is an acidic solution with a pH less than 7.0, the pH of the solution is preferably 6 or lower, more preferably 5 or lower, even more preferably 4 or lower, and particularly preferably 2 or lower, with no particular lower limit, but for example, 0 or higher.

[0050] Acidic substances are not particularly limited as long as their pH is less than 7.0 when dissolved in water. Examples of acidic substances include hydrogen fluoride, nitric acid, hydrogen peroxide, phosphoric acid, hydrochloric acid, hydrofluoric acid, sulfuric acid, oxalic acid, R１１ -COOH (R １１ is a monovalent hydrocarbon group which may have a hydrogen atom or a halogen atom.), R １２ -SO ３ H (R １２ is a monovalent hydrocarbon group which may have a chlorine atom, a fluorine atom or a halogen atom.), ammonium chloride, ammonium sulfate, ammonium nitrate, aluminum chloride, aluminum sulfate, aluminum nitrate, acidic ammonium fluoride, etc. may be mentioned. These may be used alone or in combination of two or more kinds.

[0051] R １１ 、R １２ The carbon number of the monovalent hydrocarbon group which may have a halogen atom of R

[0052] 、R １１ 、R １２ is preferably 1 to 10, more preferably 1 to 5. Examples of the monovalent hydrocarbon group which may have a halogen atom of R

[0053] 、R １１ 、R １２ include, for example, an alkyl group, an alkenyl group, an alkynyl group, etc. Among them, an alkyl group is preferable. Some or all of the hydrogens constituting these groups may be substituted with a halogen atom.

[0053] R １１ 、R １２ Examples of the alkyl group of R

[0054] 、R １１ 、R １２ include, for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, etc. Among them, a methyl group is preferable. The alkyl group may be linear or branched when the carbon number is 3 or more. The propyl group means an n-propyl group or an isopropyl group, the butyl group means an n-butyl group, a sec-butyl group or a tert-butyl group, and the same applies to other groups which may be linear or branched.

[0054] R １１ 、R １２ Examples of the alkenyl group of R

[0055] R １１ , R １２ Examples of alkynyl groups include ethynyl groups and propagyl groups, which may be linear or branched if they have four or more carbon atoms.

[0056] Examples of halogen atoms in hydrocarbon groups that may have halogen atoms include chlorine atoms, bromine atoms, and iodine atoms. These may be used individually or in combination of two or more. Among these, chlorine atoms and bromine atoms are preferred, and bromine atoms are more preferred. Examples of hydrocarbon groups having halogen atoms (preferably alkyl halogenated groups) include trifluoromethyl groups and difluoromethyl groups.

[0057] R １１ It is preferable that it is a monovalent hydrocarbon group which may have a hydrogen atom and a halogen atom. １２ It is preferable that this is a monovalent hydrocarbon group which may have a chlorine atom, a fluorine atom, or a halogen atom.

[0058] R １１ Examples of -COOH include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, pentadecyl acid, palmitic acid, palmitoleic acid, margaric acid, stearic acid, oleic acid, vaccenic acid, linoleic acid, linolenic acid, arachidic acid, behenic acid, lignoceric acid, and nervonic acid. These may be used individually or in combination of two or more. Among these, formic acid and acetic acid are preferred.

[0059] R １２ -SO ３ Examples of H include methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, trifluoromethanesulfonic acid, and difluoromethanesulfonic acid. These may be used individually or in combination of two or more. Among these, methanesulfonic acid and trifluoromethanesulfonic acid are preferred.

[0060] Preferred acidic substances include hydrogen fluoride, hydrofluoric acid, nitric acid, phosphoric acid, and hydrogen peroxide, with hydrogen fluoride and nitric acid being more preferred.

[0061] The alkaline substance is not particularly limited as long as it has a pH greater than 7.0 when dissolved in water. Examples of alkaline substances include alkali metal hydroxides, alkali metal carbonates, alkali metal phosphates, alkali metal acetates, alkaline earth metal hydroxides, alkaline earth metal carbonates, alkaline earth metal phosphates, alkaline earth metal acetates, ammonia, tetramethylammonium hydroxide, and compounds shown in the general formula (1) below. These may be used individually or in combination of two or more. (In general formula (1), N is a nitrogen atom. R １ This is a hydrocarbon group that may have a ring, heteroatom, or halogen atom with 1 to 10 carbon atoms. ２ , R ３ This is a hydrocarbon group which may have a hydrogen atom or a ring, heteroatom, or halogen atom having 1 to 10 carbon atoms. However, if the hydrocarbon group has 3 or more carbon atoms, it may have a branched chain structure or a cyclic structure. The heteroatom of the hydrocarbon group is a nitrogen atom, oxygen atom, sulfur atom, or phosphorus atom. Furthermore, R １ and R ２ If both are hydrocarbon groups having 1 or more carbon atoms, R １ and R ２ They may be directly bonded to form a cyclic structure. Furthermore, R １ or R ２ When R is directly bonded by a double bond to form a cyclic structure, ３ Aromatic rings may be formed even without the presence of R. １ , R ２ and R ３ (These may be the same hydrocarbon group or different hydrocarbon groups.)

[0062] Examples of alkali metals include lithium, sodium, potassium, rubidium, cesium, and francium. These may be used individually or in combination of two or more. Among these, lithium, sodium, and potassium are preferred, with sodium and potassium being more preferred.

[0063] Examples of alkaline earth metals include beryllium, magnesium, calcium, strontium, barium, and radium. These may be used individually or in combination of two or more. Among these, magnesium, calcium, and barium are preferred, with magnesium and calcium being more preferred.

[0064] Among alkali metal hydroxides, alkali metal carbonates, alkali metal phosphates, alkali metal acetates, alkaline earth metal hydroxides, alkaline earth metal carbonates, alkaline earth metal phosphates, and alkaline earth metal acetates, alkali metal hydroxides and alkaline earth metal hydroxides are preferred, and alkali metal hydroxides are more preferred.

[0065] Examples of alkali metal hydroxides, alkali metal carbonates, alkali metal phosphates, alkali metal acetates, alkaline earth metal hydroxides, alkaline earth metal carbonates, alkaline earth metal phosphates, and alkaline earth metal acetates include sodium hydroxide, sodium carbonate, trisodium phosphate, sodium acetate, potassium hydroxide, potassium carbonate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, tripotassium phosphate, potassium acetate, magnesium hydroxide, magnesium carbonate, magnesium phosphate, magnesium acetate, calcium hydroxide, calcium carbonate, calcium phosphate, calcium acetate, barium hydroxide, barium carbonate, barium phosphate, and barium acetate. These may be used individually or in combination of two or more. Among these, sodium hydroxide, potassium hydroxide, and calcium hydroxide are preferred, sodium hydroxide and potassium hydroxide are more preferred, and sodium hydroxide is even more preferred.

[0066] R in general formula (1) １ Examples include methyl groups, ethyl groups, propyl groups, and butyl groups, and some of the hydrogen atoms constituting these organic groups may be substituted with halogens such as fluorine and chlorine. R in general formula (1) ２ and R ３Examples of these include hydrogen atoms, methyl groups, ethyl groups, propyl groups, and butyl groups, and some or all of the hydrogen atoms constituting these organic groups may be substituted with halogens such as fluorine and chlorine. The organic amine represented by the general formula (1) above may also be a heterocyclic amine having a five-membered ring structure or a six-membered ring structure.

[0067] Examples of compounds represented by general formula (1) (organic amine compounds) include monomethylamine, dimethylamine, trimethylamine, dimethylethylamine, diethylmethylamine, monoethylamine, diethylamine, triethylamine, mononormal propylamine, dinormal propylamine, monoisopropylamine, diisopropylamine, monobutylamine, dibutylamine, monotertiary butylamine, ditertiary butylamine, pyrrolidine, piperidine, piperazine, pyridine, and pyrazine. Other specific examples include compounds in which some or all of the C-H bonds of the above compounds are replaced by C-F bonds (trifluoromethylamine, 1,1,1-trifluorodimethylamine, perfluorodimethylamine, 2,2,2-trifluoroethylamine, perfluoroethylamine, bis(2,2,2-trifluoroethyl)amine, perfluorodiethylamine, and 3-fluoropyridine). These may be used individually or in combination of two or more. Among these, monomethylamine, dimethylamine, trimethylamine, monoethylamine, triethylamine, monopropylamine, isopropylamine, 1,1,1-trifluorodimethylamine, 2,2,2-trifluoroethylamine, and bis(2,2,2-trifluoroethyl)amine are preferred due to their easy availability.

[0068] As alkaline substances, alkali metal hydroxides and ammonia are preferred, and alkali metal hydroxides are more preferred. Here, as alkali metal hydroxides, sodium hydroxide and potassium hydroxide are preferred, and sodium hydroxide is more preferred.

[0069] As stated above, the solution containing at least one of an acidic substance and an alkaline substance is not particularly limited as long as the pH is not 7.0. Therefore, as long as the pH of the solution is not 7.0, an acidic substance and an alkaline substance may be used in combination. On the other hand, for the reason that the effects of this disclosure can be obtained efficiently, it is preferable that the solution contains only one of either an acidic substance or an alkaline substance.

[0070] Examples of solvents contained in the solution include water, hydrocarbons, esters, ethers, ketones, halogenated solvents, sulfoxide solvents, alcohols, derivatives of polyhydric alcohols, and nitrogen-containing compound solvents. These may be used individually or in combination of two or more. Among these, water and alcohols are preferred, and water is more preferred.

[0071] Examples of hydrocarbons include toluene, benzene, xylene, hexane, heptane, and octane. Examples of esters include ethyl acetate, propyl acetate, butyl acetate, and ethyl acetoacetate. Examples of ethers include diethyl ether, dipropyl ether, dibutyl ether, tetrahydrofuran, and dioxane. Examples of ketones include acetone, acetylacetone, methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, cyclohexanone, and isophorone. Examples of halogen-containing solvents include perfluorocarbons such as perfluorooctane, perfluorononane, perfluorocyclopentane, perfluorocyclohexane, and hexafluorobenzene; hydrofluorocarbons such as 1,1,1,3,3-pentafluorobutane, octafluorocyclopentane, 2,3-dihydrodecafluoropentane, and Zeolora H (manufactured by Nippon Zeon); methyl perfluoroisobutyl ether, methyl perfluorobutyl ether, ethyl perfluorobutyl ether, ethyl perfluoroisobutyl ether, Asahiclean AE-3000 (manufactured by AGC), Novec HFE-7100, Novec Examples of hydrofluoroethers include HFE-7200, Novec7300, Novec7600 (all manufactured by 3M), chlorocarbons such as tetrachloromethane, hydrochlorocarbons such as chloroform, chlorofluorocarbons such as dichlorodifluoromethane, hydrochlorofluorocarbons such as 1,1-dichloro-2,2,3,3,3-pentafluoropropane, 1,3-dichloro-1,1,2,2,3-pentafluoropropane, 1-chloro-3,3,3-trifluoropropene, 1,2-dichloro-3,3,3-trifluoropropene, perfluoroethers, and perfluoropolyethers. Examples of sulfoxide solvents include dimethyl sulfoxide. Examples of alcohols include methanol, ethanol, propanol, butanol, ethylene glycol, 1,3-propanediol, and isopropyl alcohol.Examples of polyhydric alcohol derivatives include diethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, diethylene glycol diacetate, triethylene glycol dimethyl ether, ethylene glycol diacetate, ethylene glycol diethyl ether, and ethylene glycol dimethyl ether. Examples of nitrogen-containing compound solvents include formamide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, diethylamine, triethylamine, and pyridine.

[0072] The content (concentration) of the acidic substance in 100% by mass of the solution is preferably 1 to 50% by mass, more preferably 1 to 10% by mass, and even more preferably 1 to 5% by mass.

[0073] The content (concentration) of the alkaline substance in 100% by mass of the above solution is preferably 1 to 50% by mass, more preferably 1 to 10% by mass, and even more preferably 1 to 5% by mass.

[0074] The aforementioned solution may contain other components besides acidic and alkaline substances. Examples of other components include neutral substances. These may be used individually or in combination of two or more, except when only a neutral substance is present.

[0075] The total content of acidic substances, alkaline substances, and solvents in 100% by mass of the aforementioned solution is preferably 50% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, particularly preferably 95% by mass or more, most preferably 98% by mass or more, and may also be 100% by mass.

[0076] In the cleaning method of this disclosure, at least a portion of the F-containing Ge substance located on the surface of the object to be cleaned is removed by the solution. Specifically, the F-containing Ge substance located on the surface of the object to be cleaned may be brought into contact with a solution containing at least one of an acidic substance and an alkaline substance.

[0077] The method for bringing the solution into contact with the F-containing Ge substance located on the surface of the object to be cleaned is not particularly limited, and examples include immersing the object to be cleaned in the solution, spraying the solution onto the object to be cleaned, or introducing the solution into an etching apparatus in which the object to be cleaned is installed. These methods may be batch or continuous. Among these, immersing the object to be cleaned in the solution is preferred.

[0078] It is also preferable to rotate the object to be cleaned while bringing it into contact with the solution. Rotation improves the contact efficiency between the solution and the F-containing Ge substance, and therefore tends to allow for more efficient removal of the F-containing Ge substance.

[0079] The temperature of the solution when it is brought into contact with the F-containing Ge substance located on the surface of the object to be cleaned is not particularly limited, but is preferably 25 to 100°C, more preferably 25 to 50°C. The contact time is also not particularly limited, but is preferably 10 to 600 seconds, more preferably 10 to 300 seconds.

[0080] It is also preferable to perform a degassing operation on the solution before bringing it into contact with the F-containing Ge substance located on the surface of the object to be cleaned. This tends to allow for more accurate removal of the F-containing Ge substance.

[0081] There are no particular restrictions on the degassing operation, but examples include a method of degassing the gas in the solution by bubbling with an inert gas (bubbling method), a method of filling the solution into a container such as a pressure vessel and degassing the inside of the container using a vacuum pump (vacuum degassing method), a method of degassing the solution by heating it (heating degassing method), and a method of degassing the gas in the liquid by gas permeation through a permeable membrane (membrane degassing method).

[0082] The cleaning process may be carried out after the solution has been brought into contact with the F-containing Ge substance located on the surface of the object to be cleaned.

[0083] In the cleaning process, it is preferable to first immerse the object to be cleaned in a solvent to remove the solution adhering to its surface. The solvent is the same as the solvent contained in the solution, including preferred embodiments. Next, it is preferable to immerse the object to be cleaned in an organic solvent to shorten the drying time. Examples of organic solvents include the solvents described in the section on the solvent contained in the solution. Among these, alcohols are preferred.

[0084] After the washing process, a drying process may be performed. The drying method, temperature, and time are not particularly limited.

[0085] <Etching Method> The etching method of this disclosure is IF ７ , IF ５ , BrF ５ , BrF ３ MoF ６ GeF ２ GeF ４ The etching method includes a dry etching step of etching a germanium-containing film to be etched on a substrate with at least one gas selected from the group consisting of and ClF, and a cleaning step of cleaning the substrate obtained by the dry etching step with a solution containing at least one of an acidic substance and an alkaline substance. This reduces the accumulation of etching residue.

[0086] The reason why the aforementioned effects are obtained is not entirely clear, but it is presumed to be due to the following mechanism: IF ７ , IF ５ , BrF ５ , BrF ３ MoF ６ GeF ２ GeF ４ At least one gas selected from the group consisting of and ClF (also referred to as the first gas) is ClF ３It has lower oxidizing properties and also lower reactivity with germanium-containing films, offering advantages in controlling the etching rate. However, when etching a germanium-containing film using the first gas, due to its low reactivity with the germanium-containing film, etching residue containing Ge (for example, an F-containing Ge substance containing fluorine atoms and germanium atoms) is deposited on the wafer after etching. In this disclosure, the etching residue can be removed and the deposition of etching residue can be reduced by cleaning the substrate on which the etching residue has accumulated with a solution containing at least one of an acidic substance and an alkaline substance.

[0087] <<Etched Film>> The etched film containing germanium is not particularly limited as long as it contains germanium, and examples include germanium films, germanium oxide films, germanium nitride films, germanium oxynitride films, and films containing at least Si and Ge. Furthermore, germanium may form an alloy with other metals. These may be used alone or in combination of two or more. Among these, films containing at least Si and Ge are preferred, and silicon germanium is more preferred.

[0088] In the etched film containing germanium, the Ge content is preferably 1% by mass or more, more preferably 5% by mass or more, and there is no particular upper limit; it may be 100% by mass, but for example, it is 99% by mass or less. In this specification, the content of each element in the film is measured by X-ray photoelectron spectroscopy (XPS, ULVAC-PHI, PHI5000 VersaProbeII).

[0089] A film containing at least Si and Ge is silicon germanium (SiGe, where SiGe does not indicate the stoichiometric ratio of each element, but refers to a film containing silicon atoms and germanium atoms. For example, SiGe (Si １－ｘ Ge ｘ A film is an example, where x is 0.01 to 0.99, but may also be 0.05 to 0.5.

[0090] In the etching method of this disclosure, examples of the workpiece include a silicon substrate, a compound semiconductor substrate, a quartz substrate, and a glass substrate. In addition to the etched film described above, a silicon film, a silicon oxide film, a silicon nitride film, or a metal wiring film other than the metals described above may be formed on the surface of the workpiece.

[0091] The method for forming the etchable film on the surface of the object to be treated is not particularly limited, but examples include chemical vapor deposition (CVD) and sputtering. The thickness of the etchable film is also not particularly limited, but for example, it can be between 0.1 nm and 1 μm.

[0092] In the etching method disclosed herein, IF ７ , IF ５ , BrF ５ , BrF ３ MoF ６ GeF ２ GeF ４ At least one gas (first gas) selected from the group consisting of and ClF is used.

[0093] <<IF ７ , IF ５ , BrF ５ , BrF ３ MoF ６ GeF ２ GeF ４ At least one gas (first gas) selected from the group consisting of and ClF >> IF ７ , IF ５ , BrF ５ , BrF ３ MoF ６ GeF ２ GeF ４ As at least one gas (first gas) selected from the group consisting of and ClF, is IF ７ , IF ５ ClF, MoF ６ Preferably, it is at least one gas selected from the group consisting of IF ７ , IF ５ It is more preferable that it be at least one gas selected from the group consisting of ClF, and IF ７It is even more preferable that this is the case. The first gas may be used alone, or two or more may be used in combination.

[0094] IF ７ , IF ５ , BrF ５ , BrF ３ MoF ６ GeF ２ GeF ４ The gas containing at least one gas (first gas) selected from the group consisting of and ClF is not particularly limited as long as it contains the first gas, but may also contain inert gases and the like.

[0095] Examples of inert gases include Ar and N. ２ Examples include He, Ne, and Kr. These may be used individually or in combination of two or more.

[0096] In a gas containing the first gas, the content of the first gas can be, for example, 10 to 100 volume percent in 100 volume percent of the gas. In this case, the content of the inert gas can be, for example, 0 to 90 volume percent in a gas containing the first gas. In this specification, the content of each gas component is measured, for example, by infrared spectroscopy.

[0097] In 100% by volume of the gas containing the first gas, the total content of the first gas and the inert gas is preferably 80% by volume or more, more preferably 90% by volume or more, even more preferably 95% by volume or more, and particularly preferably 98% by volume or more, and may be 100% by volume.

[0098] In the etching method of this disclosure, it is preferable to bring the first gas into contact with the film to be etched in a non-plasma environment without creating a plasma state. This is because, if the object to be processed is a semiconductor device substrate, contact with a plasma gas may cause electrical damage to the substrate due to the plasma gas.

[0099] The etching temperature is preferably 0 to 300°C, more preferably 10°C or higher, particularly preferably 20°C or higher, and most preferably 25°C or higher, for the reason that the film to be etched can be etched more effectively. For the reason that damage to the film to be etched can be reduced, it is more preferably 250°C or lower, even more preferably 200°C or lower, and particularly preferably 150°C or lower. Note that the etching temperature is the temperature of the substrate (film to be etched) when processed in the dry etching process, and is equal to the temperature of the stage if the substrate is placed on a stage.

[0100] In the etching method of this disclosure, it is preferable to exclude the following: "an etching method comprising: a step of storing a substrate having recesses formed by side walls that are germanium-containing films in a processing container; an etching step of supplying an etching gas containing a first fluorine-containing gas and a second fluorine-containing gas into the processing container and etching the first side walls and the second side walls; and a shape control step included in the etching step, which controls the shape of the side walls after etching by adjusting the partial pressure of the first fluorine-containing gas in the processing container or the ratio of the flow rate of the second fluorine-containing gas to the first fluorine-containing gas supplied into the processing container."

[0101] [Dry Etching Method (Dry Etching Process)] The following describes a dry etching process in which a gas containing "the first gas" is brought into contact with the film to be etched. In the dry etching process, a gas A containing at least the first gas is brought into contact with the film to be etched.

[0102] In the dry etching process, etching can be performed using a first gas.

[0103] The first gas contained in gas A is as described above, including in preferred embodiments.

[0104] In gas A, the partial pressure of the first gas is preferably 0.1 to 10 Pa, more preferably 0.1 to 9.0 Pa, even more preferably 0.1 to 5.0 Pa, and particularly preferably 0.1 to 2.0 Pa. Furthermore, from the viewpoint of increasing the etching rate, the partial pressure of the first gas in gas A may be 0.3 Pa or higher, 0.4 Pa or higher, or 0.8 Pa or higher. The partial pressure of the first gas is IF ７ Partial voltage, IF ５ Partial pressure of BrF ５ Partial pressure of BrF ３ Partial pressure, MoF ６ Partial pressure of GeF ２ Partial pressure of GeF ４ This refers to the sum of the partial pressures of and . The same applies to other similar descriptions. In this specification, the partial pressure of each gas component is measured by a pressure gauge. Specifically, the total pressure is measured by a pressure gauge, and the partial pressure of each gas component is calculated from the flow rate ratio of the gas components being introduced.

[0105] Gas A is not particularly limited as long as it contains the first gas, but it may also contain other gases such as inert gases. The inert gases are as described above.

[0106] In 100% by volume of gas A, the content of the first gas can be, for example, 10 to 100% by volume. In this case, in 100% by volume of gas A, the content of the inert gas can be, for example, 0 to 90% by volume.

[0107] In 100% by volume of gas A, the total content of the first gas and the inert gas is preferably 80% by volume or more, more preferably 90% by volume or more, even more preferably 95% by volume or more, and particularly preferably 98% by volume or more, and may be 100% by volume.

[0108] In the dry etching process, it is preferable to place the workpiece inside a processing vessel and perform the etching. In the dry etching process, it is preferable to bring gas A into contact with the film to be etched, and then to reduce the pressure inside the processing vessel. This is because it is possible to remove by-products generated during etching. Reduced pressure means that the pressure inside the processing vessel is lower than the pressure during etching, and is generally 0.133 kPa or less.

[0109] In the dry etching process, it is preferable to bring gas A into contact with the film to be etched, and then replace the inside of the processing container with an inert gas. This is because it is possible to remove by-products generated during etching. Alternatively, the dry etching process may involve first reducing the pressure inside the processing container, and then replacing the inside of the processing container with an inert gas.

[0110] (Dry etching process using an etching apparatus) The dry etching process can be realized, for example, by using the etching apparatus shown in Figure 1. Figure 1 is a schematic diagram of the etching apparatus used in the embodiment of this disclosure. Below, the dry etching process will be specifically described using the etching apparatus of Figure 1 as an example. The etching apparatus of this disclosure includes a mounting table on which the workpiece to be processed is placed, and an IF ７ , IF ５ , BrF ５ , BrF ３ MoF ６ GeF ２ GeF ４ The etching apparatus comprises a first gas supply unit that supplies at least one gas (first gas) selected from the group consisting of and ClF. The etching apparatus of this disclosure may further comprise an inert gas supply unit that supplies an inert gas.

[0111] In the etching apparatus of this disclosure, it is preferable to exclude the following: "an etching apparatus comprising: a processing container for storing a substrate having recesses formed by side walls that are germanium-containing films; an etching gas supply unit for supplying etching gases containing a first fluorine-containing gas and a second fluorine-containing gas into the processing container for etching the side walls; and an adjustment unit for adjusting the partial pressure of the first fluorine-containing gas in the processing container during etching, or adjusting the flow rate ratio of the second fluorine-containing gas to the first fluorine-containing gas supplied into the processing container, in order to control the shape of the side walls after etching."

[0112] In the dry etching process, gas A containing a first gas (also simply referred to as the first gas) is brought into contact with the film to be etched. First, the workpiece 10 on which the germanium-containing etched film has been formed is placed on the mounting section 111 in the processing container 110. Next, the processing container 110, piping 121, piping 141 and 142, piping 151 and 152, liquid nitrogen trap 194, and piping 191 are evacuated to a predetermined pressure using a vacuum pump 193, and then the workpiece 10 is heated using a heating means 190.

[0113] When the object to be processed 10 reaches a predetermined temperature, the first gas supply unit 140 supplies the first gas to the piping 121 at a predetermined flow rate. The first gas supply unit 140 adjusts the supply amount using valves V1 and V2 and flow rate adjustment means MFC2 to supply the first gas to the piping 121 from piping 141 and 142.

[0114] Alternatively, inert gas may be supplied to the piping 121 from the inert gas supply unit 150 at a predetermined flow rate. The inert gas supply unit 150 adjusts the supply amount using valves V3 and V4 and flow rate adjustment means MFC3 to supply inert gas from piping 151 and 152 to piping 121.

[0115] In Figure 1, PI1 and PI2 are pressure gauges, and their readings are used to control each flow rate adjustment means and each valve.

[0116] The first gas is mixed with an inert gas in a predetermined composition as needed and supplied to the processing container 110. While introducing the mixed gas into the processing container 110, the pressure inside the processing container 110 is controlled to a predetermined level. Etching is performed by bringing the gas into contact with the film to be etched, which contains germanium, for a predetermined time. In this dry etching process, etching is possible without a plasma state, and gas excitation with plasma or the like is not required during etching. The gas flow rate can be appropriately set based on the volume and pressure of the processing container.

[0117] In addition, etching accompanied by a plasma state refers to a process in which, for example, a gas of about 0.01 to 1.33 kPa is introduced into the reactor, and high-frequency power is applied to an external coil or counter electrode to generate a low-temperature gas plasma in the reactor, and etching is performed by activating chemical species such as ions and radicals that are formed within it. In the dry etching process of this disclosure, the gas is brought into contact without the formation of a plasma state, and dry etching can be performed without generating the gas plasma described above.

[0118] After etching is complete, heating by the heating means 190 is stopped and the temperature is lowered, and the vacuum pump 193 is stopped and the vacuum is released by replacing it with an inert gas. As described above, the dry etching method using the etching apparatus can be used to etch a film containing germanium.

[0119] (Etching conditions in the dry etching process) In the dry etching process, the temperature of the film to be etched is the same as the temperature during etching as described above. The surface temperature of the workpiece is substantially equal to the temperature of the film to be etched, but during the etching reaction, the surface temperature of the workpiece and the temperature of the film to be etched may rise due to the heat of the reaction. In this disclosure, it is preferable that at least the temperature during etching, i.e., the temperature inside the processing container or the temperature of the mounting section on which the workpiece is placed, is within the above temperature range.

[0120] Furthermore, the pressure inside the processing vessel during etching is not particularly limited, but is usually between 0.1 Pa and 101.3 kPa. It is preferable to perform etching within the preferred partial pressure range described in the [Dry Etching Method (Dry Etching Process)].

[0121] The etching process time is not particularly limited, but considering the efficiency of the semiconductor device manufacturing process, it is preferably within 60 minutes. Here, the etching process time refers to the time from introducing gas into the processing container in which the workpiece is placed until the mixed gas in the processing container is exhausted by a vacuum pump or the like to complete the etching process.

[0122] [Cleaning Step] In the etching method of the present disclosure, after performing a dry etching step, a cleaning step is performed in which the substrate obtained by the dry etching step is cleaned with a solution containing at least one of an acidic substance and an alkaline substance.

[0123] The cleaning process can be carried out by the cleaning method of this disclosure described above.

[0124] The etching method of this disclosure is not particularly limited in that it includes a dry etching step and a cleaning step performed after the dry etching step, and may further include other steps. Of course, the etching method of this disclosure may include other steps between the dry etching step and the cleaning step.

[0125] <Method for Manufacturing Semiconductor Devices> The cleaning method of the present disclosure described above can remove at least a portion of the F-containing Ge substance, and can therefore be used to clean the substrate surface and remove etching residue, making it suitably applicable to the manufacturing process of semiconductor devices. Furthermore, the etching method of the present disclosure described above can be used as an etching method for forming a predetermined pattern on a germanium-containing film of a semiconductor device. By etching a germanium-containing film on a substrate using the etching method of the present disclosure, a semiconductor device can be manufactured.

[0126] Therefore, the method for manufacturing a semiconductor device of the present disclosure includes a step using the cleaning method or etching method of the present disclosure.

[0127] The method for manufacturing a semiconductor device according to the present disclosure is characterized by including a step of applying the cleaning method according to the present disclosure to an F-containing Ge substance located on the surface of a substrate that is to be cleaned, thereby removing at least a portion of the F-containing Ge substance. The step of applying the cleaning method according to the present disclosure to remove at least a portion of the F-containing Ge substance can be carried out by the cleaning method according to the present disclosure as described above.

[0128] Furthermore, the method for manufacturing a semiconductor device according to this disclosure is characterized by including a step of etching a germanium-containing film on a substrate by applying the etching method according to this disclosure. The step of etching the film can be carried out by the etching method according to this disclosure as described above.

[0129] <Etching System> The etching method of this disclosure can be realized, for example, by using the etching system described below. Such an etching system is also one of the disclosures. The etching system of this disclosure comprises a mounting table on which the workpiece is placed, and an IF (Integrated Focus) on the workpiece. ７ , IF ５ , BrF ５ , BrF ３ MoF ６ GeF ２ GeF ４ The system includes a gas supply unit that supplies at least one gas selected from the group consisting of and ClF, and a cleaning unit that brings a solution containing at least one of an acidic substance and an alkaline substance into contact with the workpiece. More specifically, for example, the etching system of the present disclosure includes a mounting table on which the workpiece is placed, and an IF (Internal Fluid) solution that brings the workpiece into contact with the workpiece. ７ , IF ５ , BrF ５ , BrF ３ MoF ６ GeF ２ GeF ４ A dry etching apparatus comprising: a gas supply unit that supplies at least one gas selected from the group consisting of and ClF; and a cleaning apparatus comprising a cleaning unit that brings a solution containing at least one of an acidic substance and an alkaline substance into contact with an object to be treated. The dry etching apparatus comprising the etching system of this disclosure may further comprise an inert gas supply unit that supplies an inert gas into the chamber.

[0130] The dry etching apparatus is as described in (Dry etching process using etching apparatus).

[0131] The cleaning apparatus is not particularly limited as long as it includes a cleaning unit that brings a solution containing at least one of an acidic substance and an alkaline substance into contact with the object to be treated. The specific configuration of the cleaning apparatus can be appropriately set according to the form in which it is implemented. For example, the cleaning apparatus may include a storage unit (e.g., a tank) (not shown) for storing the solution and a cleaning unit (e.g., a tank separate from the storage unit's tank) (not shown) for bringing the solution into contact with the object to be treated.

[0132] When immersing an object to be cleaned in the solution, the solution stored in the storage unit is supplied to the cleaning unit, and the object to be cleaned is immersed in the solution in the cleaning unit where the solution has been supplied.

[0133] Furthermore, when spraying the solution onto an object to be cleaned, the object to be cleaned should be placed on the cleaning unit, and the solution stored in the storage unit should be sprayed onto the placed object.

[0134] Furthermore, as described above, the solution may be introduced into an etching apparatus on which the object to be cleaned is placed. In this case, it is not necessarily required to provide a dry etching apparatus and a cleaning apparatus separately, and the dry etching apparatus may also serve as the cleaning apparatus. For example, the solution stored in the storage section may be supplied to a chamber in the etching apparatus, and the solution may be brought into contact with the object to be processed within the chamber. In this case, the chamber corresponds to the cleaning section. In such an embodiment, the etching system of the present disclosure comprises a mounting table on which the object to be processed is placed, and an IF (Integrated Focus) to the object to be processed. ７ , IF ５ , BrF ５ , BrF ３ MoF ６ GeF ２ GeF ４ The dry etching apparatus comprises a gas supply unit that supplies at least one gas selected from the group consisting of and ClF, and a cleaning unit that brings a solution containing at least one of an acidic substance and an alkaline substance into contact with the object to be treated.

[0135] Figure 2 is a schematic diagram illustrating an etching system according to one embodiment of the present disclosure. As shown in Figure 2, the etching system 300 comprises an etching apparatus 100 and a cleaning apparatus 200. The chamber of the etching apparatus 100 and the chamber of the cleaning apparatus 200 are connected while being separated by a gate valve, and substrates may be transported between the chambers without contact with the outside air.

[0136] Examples of the present disclosure, along with comparative examples, are listed below, but the present disclosure is not limited to these examples. In the examples and comparative examples, the gases used in the first step are as shown in each table, and each gas is not diluted with an inert gas or the like (it does not contain any components other than those listed in the table), and in the gas used in the first step in Table 1, the content of the gases listed in Table 1 in the gas is 100% by volume.

[0137] [Example 1] IF ７ A cylinder filled with [a substance] and an aluminum etching chamber were connected using SUS304 metal piping to form an etching apparatus. The first step, dry etching, was carried out using the etching apparatus shown in Figure 1. First, a silicon germanium wafer (SiO on Si) ２ A film with a 100 nm thin layer of material deposited on top of it, and then a 1000 nm layer of SiGe deposited on top of that (with a Si to Ge composition ratio of 7:3), was introduced into the etching chamber and the stage temperature was set to 25°C. The temperature of the substrate (wafer) is the same as the stage temperature, which is the temperature of the mounting platform, and is essentially equal to the temperature of the film to be etched. Next, IF ７ The flow rate was set to 10 sccm and circulated into the chamber. The pressure inside the chamber was adjusted using a pressure regulating valve to maintain a pressure of 0.5 Pa. IF ７ After circulating the gas for 100 seconds, the gas flow was stopped. Note that the IF in the gas... ７ The content was 100% by volume. Afterward, the silicon germanium wafer was removed from the chamber. As a second step, the silicon germanium wafer processed in the first step was immersed in a 0.1% by mass HF aqueous solution (25°C) for 1 minute to remove etching residue. Then, to wash away the HF aqueous solution adhering to the wafer, it was immersed in ultrapure water for 1 minute, and then in IPA (isopropyl alcohol) for 1 minute, followed by N ２ The IPA was removed by spraying it onto the wafer. Observation of the wafer's cross-section with a scanning electron microscope (SEM, Hitachi SU-8000) confirmed that the Ge compound residue deposited on the silicon germanium wafer had disappeared. Thus, IF ７We confirmed that the Ge compound residue generated on the wafer after etching using [the specified method] can be removed by immersing it in an HF aqueous solution.

[0138] [Examples 2-18] The first step was carried out in the same procedure as in Example 1, except that the pressure was changed as shown in Table 1. The second step was also carried out in the same procedure as in Example 1, except that the concentration and type of solution were changed as shown in Table 1.

[0139] [Comparative Example 1] Etching was performed using the same apparatus as in Example 1. First, the first step was performed in the same manner as in Example 1. Then, the silicon germanium wafer was removed from the chamber and the cross-section of the wafer was observed using a scanning electron microscope (SEM, HITACHI SU-8000). Also, the SiO underlay of the SiGe film was observed. ２ We confirmed that particulate matter was deposited on the film. Analysis of the particulate matter using XPS (X-ray photoelectron spectroscopy) revealed that the peak originating from the Ge-Si bond had disappeared, confirming that the particulate matter was not SiGe. On the other hand, a new peak originating from the Ge-F bond appeared, indicating that the particulate etching residue was a fluorine-containing Ge compound (a Ge-containing substance containing fluorine and germanium atoms (57% germanium atom content and 43% fluorine atom content)).

[0140] [Comparative Examples 2-5] The procedure was the same as in Comparative Example 1, except that the pressure and temperature of the first step were changed as shown in Table 1.

[0141] [Comparative Example 6] The procedure was the same as in Example 1, except that the solution in the second step of Example 1 was changed to water.

[0142] [Comparative Examples 7-10] The procedure was the same as in Comparative Example 6, except that the pressure and temperature of the first step were changed as shown in Table 1.

[0143] The pH of the HF aqueous solution (HFaq) used in the above experiment was 1. ３ The pH of the aqueous solution (HNO3aq) is 1. ３ PO ４ The pH of the aqueous solution (H3PO4aq) is 2. ２ O２ The pH of an aqueous solution (H₂O₂aq) is 5, the pH of an aqueous NaOH solution (NaOHaq) is 13, NH ３ The pH of the aqueous solution (NH4OHaq) was 12.

[0144] (Evaluation of Etching Residue) For Examples 1 to 18 and Comparative Examples 6 to 10, after the second step was completed, the cross-section of the wafer was observed using a scanning electron microscope (SEM, HITACHI SU-8000). The observation area was set to 100%, and the percentage of that area covered by the residue was calculated. For Comparative Examples 1 to 5, the same observation was performed after the first step was completed, and the residue was calculated. (Calculation of Etching Residue Removal Rate) Using the etching residue values ​​obtained above, Comparative Examples 1 to 5 were designated as "before cleaning," and Examples 1 to 18 and Comparative Examples 6 to 10 as "after cleaning," and the removal rate was calculated based on the following formula using the corresponding pre-cleaning and post-cleaning values. <Formula> (Area before removal (%) - Area after removal (%)) / (Area before removal (%)) × 100 <After removal; Before removal> - Examples 1, 4, 7, 10, 13, 16, Comparative Example 6; Comparative Example 1 - Examples 2, 5, 8, 11, 14, 17, Comparative Example 7; Comparative Example 2 - Examples 3, 6, 9, 12, 15, 18, Comparative Example 8; Comparative Example 3 - Comparative Example 9; Comparative Example 4 - Comparative Example 10; Comparative Example 5

[0145]

[0146] Experimental data is omitted, but ClF ３ When used, no residue was observed, IF ７ Residue was only observed when using [specific method / tool]. The generation of etching residue was due to [specific method / tool]. ７ , IF ５ , BrF ５ , BrF ３ MoF ６ GeF ２ GeF ４ Furthermore, this is a phenomenon specific to ClF and has been newly confirmed by the inventors.

[0147] From Table 1, IF ７When SiGe was etched using [a specific method], it was confirmed that the residue (for example, a F-containing Ge substance containing fluorine and germanium atoms) was reduced by contacting it with a solution containing at least one of an acidic substance and an alkaline substance. On the other hand, as shown in Comparative Examples 6 to 10, it was found that the etching residue was not removed by contact with water alone.

[0148] From the above, it was found that in the cleaning method of the example, in which at least a portion of the F-containing Ge substance containing fluorine atoms and germanium atoms located on the surface of the object to be cleaned is removed by a solution containing at least one of an acidic substance and an alkaline substance, at least a portion of the F-containing Ge substance can be removed. Furthermore, IF ７ , IF ５ , BrF ５ , BrF ３ MoF ６ GeF ２ GeF ４ In the etching method of the example, which includes a dry etching step of etching a germanium-containing film to be etched on a substrate with at least one gas selected from the group consisting of and ClF, and a cleaning step of cleaning the substrate obtained by the dry etching step with a solution containing at least one of an acidic substance and an alkaline substance, it was found that the deposition of etching residue can be reduced.

[0149] 10 Workpiece 100 Etching apparatus 110 Processing container 111 Mounting section 121 Piping 140 First gas supply section 141, 142 Piping 150 Inert gas supply section 151, 152 Piping 190 Heating means 191, 192 Piping 193 Vacuum pump 194 Liquid nitrogen trap 200 Cleaning apparatus 300 Etching system MFC2, MFC3 Flow rate adjustment means PI1, PI2 Pressure gauges V1, V2, V3, V4, V5, V6 Valves

Claims

1. A cleaning method for removing at least a portion of a fluorine-containing and germanium-containing substance located on the surface of an object to be cleaned, using a solution containing at least one of an acidic substance and an alkaline substance.

2. The acidic substance is hydrogen fluoride, nitric acid, hydrogen peroxide, phosphoric acid, hydrochloric acid, hydrofluoric acid, sulfuric acid, oxalic acid, R １１ -COOH(R) １１ This is a monovalent hydrocarbon group which may have a hydrogen atom or a halogen atom. ), R １２ -SO ３ H(R) １２ The cleaning method according to claim 1, wherein is a monovalent hydrocarbon group which may have a chlorine atom, a fluorine atom, or a halogen atom, and is at least one selected from the group consisting of ammonium chloride, ammonium sulfate, ammonium nitrate, aluminum chloride, aluminum sulfate, aluminum nitrate, and acidic ammonium fluoride.

3. The cleaning method according to claim 1, wherein the acidic substance is at least one selected from the group consisting of hydrogen fluoride, hydrofluoric acid, nitric acid, phosphoric acid, and hydrogen peroxide.

4. The cleaning method according to claim 1, wherein the acidic substance is at least one selected from the group consisting of hydrogen fluoride and nitric acid.

5. The cleaning method according to claim 1, wherein the alkaline substance is at least one selected from the group consisting of hydroxides of alkali metals, carbonates of alkali metals, phosphates of alkali metals, acetates of alkali metals, hydroxides of alkaline earth metals, carbonates of alkaline earth metals, phosphates of alkaline earth metals, acetates of alkaline earth metals, ammonia, tetramethylammonium hydroxide, and a compound represented by the following general formula (1). (In general formula (1), N is a nitrogen atom. R １ is a hydrocarbon group which may have a ring having 1 to 10 carbon atoms, a hetero atom, or a halogen atom. R ２ , R ３ is a hydrogen atom or a hydrocarbon group which may have a ring having 1 to 10 carbon atoms, a hetero atom, or a halogen atom. However, when the hydrocarbon group has 3 or more carbon atoms, it may have a branched-chain structure or a cyclic structure. The hetero atom of the hydrocarbon group is a nitrogen atom, an oxygen atom, a sulfur atom, or a phosphorus atom. Further, when both R １ and R ２ are hydrocarbon groups having 1 or more carbon atoms, R １ and R ２ may be directly bonded to form a cyclic structure. Further, when R １ or R ２ is directly bonded by a double bond to form a cyclic structure, an aromatic ring may be formed without the presence of R ３ . Also, R １ , R ２ and R ３ may be the same hydrocarbon group or different hydrocarbon groups.) 6. The cleaning method according to claim 1, wherein the alkaline substance is at least one selected from the group consisting of alkali metal hydroxides and ammonia.

7. The cleaning method according to claim 1, wherein the alkaline substance is an alkali metal hydroxide.

8. The cleaning method according to claim 1, wherein the alkaline substance is at least one selected from the group consisting of sodium hydroxide and ammonia.

9. The cleaning method according to claim 1, wherein the alkaline substance is sodium hydroxide.

10. The washing method according to claim 1, wherein the solvent contained in the solution is at least one selected from the group consisting of water, hydrocarbons, esters, ethers, ketones, halogen-containing solvents, sulfoxide solvents, alcohols, derivatives of polyhydric alcohols, and nitrogen-containing compound solvents.

11. The washing method according to claim 1, wherein the solvent contained in the solution is water.

12. IF ７ , IF ５ , BrF ５ , BrF ３ MoF ６ GeF ２ GeF ４ An etching method comprising: a dry etching step of etching a germanium-containing film to be etched on a substrate with at least one gas selected from the group consisting of and ClF; and a cleaning step of cleaning the substrate obtained by the dry etching step with a solution containing at least one of an acidic substance and an alkaline substance.

13. The acidic substance is hydrogen fluoride, nitric acid, hydrogen peroxide, phosphoric acid, hydrochloric acid, hydrofluoric acid, sulfuric acid, oxalic acid, R １１ -COOH(R) １１ This is a monovalent hydrocarbon group which may have a hydrogen atom or a halogen atom. ), R １２ -SO ３ H(R) １２ The etching method according to claim 12, wherein is a monovalent hydrocarbon group which may have a chlorine atom, a fluorine atom, or a halogen atom, and is at least one selected from the group consisting of ammonium chloride, ammonium sulfate, ammonium nitrate, aluminum chloride, aluminum sulfate, aluminum nitrate, and acidic ammonium fluoride.

14. The etching method according to claim 12, wherein the acidic substance is at least one selected from the group consisting of hydrogen fluoride, hydrofluoric acid, nitric acid, phosphoric acid, and hydrogen peroxide.

15. The etching method according to claim 12, wherein the acidic substance is at least one selected from the group consisting of hydrogen fluoride and nitric acid.

16. The etching method according to claim 12, wherein the alkaline substance is at least one selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, alkali metal phosphates, alkali metal acetates, alkaline earth metal hydroxides, alkaline earth metal carbonates, alkaline earth metal phosphates, alkaline earth metal acetates, ammonia, tetramethylammonium hydroxide, and compounds represented by the following general formula (1). (In general formula (1), N is a nitrogen atom. R １ This is a hydrocarbon group that may have a ring, heteroatom, or halogen atom with 1 to 10 carbon atoms. ２ , R ３ This is a hydrocarbon group which may have a hydrogen atom or a ring, heteroatom, or halogen atom having 1 to 10 carbon atoms. However, if the hydrocarbon group has 3 or more carbon atoms, it may have a branched chain structure or a cyclic structure. The heteroatom of the hydrocarbon group is a nitrogen atom, oxygen atom, sulfur atom, or phosphorus atom. Furthermore, R １ and R ２ If both are hydrocarbon groups having 1 or more carbon atoms, R １ and R ２ They may be directly bonded to form a cyclic structure. Furthermore, R １ or R ２ When R is directly bonded by a double bond to form a cyclic structure, ３ Aromatic rings may be formed even without the presence of R. １ , R ２ and R ３ (These may be the same hydrocarbon group or different hydrocarbon groups.) 17. The etching method according to claim 12, wherein the alkaline substance is at least one selected from the group consisting of alkali metal hydroxides and ammonia.

18. The etching method according to claim 12, wherein the alkaline substance is an alkali metal hydroxide.

19. The etching method according to claim 12, wherein the alkaline substance is at least one selected from the group consisting of sodium hydroxide and ammonia.

20. The etching method according to claim 12, wherein the alkaline substance is sodium hydroxide.

21. The etching method according to claim 12, wherein the solvent contained in the solution is at least one selected from the group consisting of water, hydrocarbons, esters, ethers, ketones, halogen-containing solvents, sulfoxide solvents, alcohols, derivatives of polyhydric alcohols, and nitrogen-containing compound solvents.

22. The etching method according to claim 12, wherein the solvent contained in the solution is water.

23. The aforementioned gas is IF ７ The etching method according to claim 12.

24. A method for manufacturing a semiconductor device, comprising a step using the cleaning method described in any one of claims 1 to 11 or the etching method described in any one of claims 12 to 23.

25. A platform on which the object to be processed is placed, and an IF (Internal Fault Line) to the object to be processed. ７ , IF ５ , BrF ５ , BrF ３ MoF ６ GeF ２ GeF ４ An etching system comprising: a gas supply unit that supplies at least one gas selected from the group consisting of and ClF; and a cleaning unit that brings a solution containing at least one of an acidic substance and an alkaline substance into contact with an object to be treated.

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